5161 5165.output

* GB785568 (A)

Description: GB785568 (A) ? 1957-10-30

Improvements in or relating to frequency divider circuits

Description of GB785568 (A)

A high quality text as facsimile in your desired language may be available amongst the following family members:

DE1034217 (B) DE1034217 (B) less Translate this text into Tooltip

[79][(1)__Select language] Translate this text into

The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION 785,568 Date of Application and filing Complete Specification Sept 16, 1955. No 26561/55. Application made in United States of America on Sept 17, 1954. Complete Specification Published Oct 30, 1957. Index at Acceptance:-Class 40 ( 6), G( 1 G: 2 A), P( 1 F: 1 M 3: 1 U: 2 A: 2 D: 4 R). International Classification: -H 03 k. COMPLETE SPECIFICATION Improvements in or relating to Frequency Divider Circuits We, WESTERN ELECTRIC COMPANY, INCORPORATED, of 195, Broadway, New York City, New York State, United States of America, a corporation of the State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by

the following statement:This invention relates to electrical circuits for effecting frequency division. In electronic computers and similar electrical information systems, a source of base or clock frequency is often provided This clock frequency serves to define the time intervals of the information digits and to synchronize the various operations of the system Additionally, however, it is necessary to provide a number of control signals In serial digital computers repetitive operations are often performed at a submultiple of the basic clock signal or frequency The initiation and synchronization of various computer operations accordingly depends on the availability of these single pulses occurring cyclically at predetermined intervals These intervals may be of the order of once every ten, hundred, thousand, or even millions of cycles of the clock frequency The generation of cyclically occurring pulses at a frequency which is a submultiple of the clock frequency has been termed frequency division. It is a general object of this invention to provide improved circuits for frequency division. According to the invention there is provided a frequency divider circuit comprising means for transmitting a single pulse at intervals of N digits of a clock frequency, an adder circuit, means for applying the single pulses to the adder circuit, means connecting the output of said adder circuit to the input thereof, said connecting means having a delay of n/k digits, where k is any positive number, and gate means for transmitting an output pulse only on occurrence of a pulse from said transmitting means and from said adder circuit on lPrice 3 s 6 d l accumulation of a predetermined number of pulses in said connecting means. In one specific embodiment of this invention, a large frequency division is attainable by employing two stages of frequency division. The first stage comprises a delay line register in which a single pulse is stored and circulated, apearing at the output once every a digits or cycles of the clock frequency The frequency division of the first stage is l/n of the clock frequency The second stage comprises a binary half adder with a delay line having an accumulation of N digits 'of the clock frequency and a gating circuit The single digit transmitted by the first stage circuit is counted by the second stage circuit until the half-adder delay line is full, at which time the gating circuit is enabled and a single pulse applied to the output lead The frequency division of the second stage is 1/2 N of the clock frequency and thus the overall frequency division is 1/(n) ( 2 a) of the clock frequency. Generally in such computers N digits would define the word or information message.

Accordingly, we can consider that the first stage of frequency division divides the clock frequency to the word frequency and the second stage of frequency division affords an output control pulse at some submultiple of the word frequency. The first stage division may be attained advantageously by a number of delay line register circuits, the various delay lines providing different delays The number of digits delay of the various lines should be relative primes or products thereof with respect to each other The outputs of the various single circuits are applied to an AND logic gate so that a pulse is transmitted to the second stage of frequency division only on the occurrence of outputs at all the angle circuits in the first stage. If it is desired to trigger the first stage of frequency division by a train of pulses at the clock frequency, rather than by a single initiating pulse, the first stage division may be attained advantageously by a number of delay 785,568 lines connected between the output and one input of an inhibitor circuit, the train of clock pulses being applied to the other input of the inhibitor circuit. Additionally, the second stage of frequency division may include circuitry for repeating the single output pulse for exactly one half the cycle between output pulses, when it is desired to obtain a sinusoidal or other cyclical wave of the lower frequency. The frequency divider may also have preset therein a number so that the frequency division attained by the second stage circuit is 1/l 2 u-(preset number)l of the zword frequency As the preset number may be any number from 0 to 27 the second stage of frequency division can attain any desired division of the word frequency As the input pulses to the second stage of frequency division need not in all cases define word frequency or word repetition rate, we can state that by presetting a number in a frequency divider circuit in accordance with this invention, any frequency division of the input pulses may be obtained provided that the frequency of the input pulses is smaller than the clock frequency which defines the digit intervals of the circuit. A complete understanding of this invention may be gained from consideration of the following detailed description and the accompanying drawings, in which:Fig 1 is a simplified block diagram of one specific illustrative embodiment of a two stage frequency divider in accordance with this invention; Fig 2 is a more detailed block diagram of the embodiment of Fig 1; Fig 3 is a pulse-time chart depicting the occurrence of pulses at various points in the emobdiment of Fig 2; Fig 4 a is a block diagram of the embodiment of Fig 2 modified to include the amplifiers and inherent delays therein; Fig 4 b is a schematic diagram of the embodiment of Fig 4 a; Fig 5 is a

block diagram of another specific illustrative embodiment of a first stage frequency divider in accordance with this invention; Fig 6 is a block diagram of another specific illustrative embodiment of this invention wherein the second stage of frequency division is preset; Fig 7 is a block digram of another specific ilustrative embodiment of this invention wherein the output is not a single pulse but a train of pulses occurring for one half the period of the output frequency of the second stage circuit; Fig 8 is a pulse-time chart depicting the occurrence of pulses at various points in the embodiment of Fig 7; and Fig 9 is a block diagram of another specific embodiment of a first stage frequeaczy divider in accordance with this invention. Turning now to the drawing, the illustrative embodiment of the invention depicted in Fig 1 accords a frequency division oi substantially 1/(n) ( 2 '1), where it is any digit A single pulse is applied, from a single pulse generator 70 10, to a delay line register frequency divider 11, which provides a recurrent output pulse once every n E digit This output 's arpl-td to a second stage of frequency division including an adder circuit 12, which may be either a 75 full or half-adder circuit The adder output is connected through an N digit delay line 13 back to the input of the adder circuit When the N digit delay line 13 is filled, i e, when sufficient digits have been added so that the 80 ouput of the adder is a succession of N pulses, a gate 14 is enabled and a single output pulse appears on an output lead 16 The adder circuit is also reset to begin the next cycle of frequency division on receipt of a pulse from 85 the first stage frequency divider 11. Accordingly, in the general combination of the specific embodiment of the invention there is a first stage of frequency division, attained by the employment of a delay line register 90 circuit, and a second stage of frequency division, attained by the employment of circuitry for the accumulation of pulses from the first stage Fig 2 depicts one specific embodiment, in block diagram form, of the embodiment of 95 the invention of Fig 1; an understanding of this embodiment can be gained from a consideration of its operation together with the pulse-time chart of Fig 3 In this embodiment it is assumed that n= 4 and that the desired 100 frequency division is 1/( 4) ( 21) or 1/64 of the clock frequency which may be of the order of 3 megacycles. In Fig 3 are depicted the pulses occurring at different points in the circuit of Fig 2 dur 105 ing the operation of that circuit; the points are labelled It, b, c, d, e, f, g, h, k, and i and will be further identified in the description of the circuit The base or clock frequency is also shown on Fig 3, although it does not appear 110 explicitly in Fig 2 However, it is to be understood that clock signals are applied to various components, such as amplifiers, within the

circuit, as more clearly seen in the circuit schematic of Fig 4 The pulses occur dur 115 ing the positive cycles of the clock frequency and in synchronism therewith; the clock frequency thus defines the digit intervals of the circuit. The initiating pulse from the single pulse 120 generator 10 is applied to the first stage frequency divider 11; the initiating pulse occurs at point a and the output of the first stage frequency divider 11, which occurs at point b, is a train of pulses, one pulse appearing for each 125 four cycles of the clock frequency as we have assumed, in this embodiment, that n= 4 The train of pulses b is applied through an OR circuit 18 to a half-adder circuit 19 A half adder is a circuit, known in the art, which has 130 785,568 an output on a first lead if one of two but not both, inputs is present and an output on a second lead if both inputs are present The first of these outputs, usually referred to as the sum output, appears at point c and the second, usually referred to as the carry output, at point e The sum output at c are trains of pulses representing successive binary digits from 1 to 2 ", which in this embodiment is from 1 to 16. To facilitate an understanding of the time chart of Fig 3 the decimal equivalent of each binary number is indicated on the drawing. The pulses appear in the four digit time slots or intervals defined by the clock frequency. For larger values of N there would of course be more time slots defined between successive pulses at point b and the outputs at point c would include binary nlumbers 'cf a larger number of digts. The pulses appearing at point c are passed through a delay line 21, which advantageously has N digits of delay, and then applied as the second input, at point d, to the halfadder circuit 19 The input at point d is thus the output at point c delayed by four digits of the clock frequency In the overall system four digits would probably represent one word or information message unit When a pulse at b and a pulse at d coincide, the output of the half-adder 19 is a pulse at point e, instead of at point c; this pulse at point e is a carry pulse and is passed through one digit of delay, by a delay line 22, to the OR circuit 18 The delayed pulse from point e applied to the OR circuit 18 appears at point f. We can thus now state the conditions for operation of the half-adder circuit 19; these are: an output appears at c if there is an input at d or an input at b or f, or b and f but not if there is an input at a and b or f; and an output appears at e if there is an input at d and an input at b or f. When the output at c is a train of pulses corresponding to the capacity of the delay line 21, a pulse is to be gated to the output lead 16 This gating is attained by a pair of AND circuits 24 and 25

and a one digit delay line 26 The output at point c is applied as one input to the AND circuit 24; the other input, at point g, is from an OR circuit 28, one input of which is from point b and the other input of which is from point k The output of the AND circuit, at point h, is delayed one digit by the delay line 26 and applied, at point k, as one input of the AND circuit 25, the other input of which is from point b. The gate circuit 14, referred to in the description of the block diagram of Fig 1, can be seen in the diagram of Fig 2 to include the OR circuit 28, AND circuits 24 and 25, and the one digit delay line 26 This circuit is a memory circuit which is triggered during the first digit interval, by a pulse from point b through OR circuit 28, if there is an output at c and which circulates a pulse as long as there is an output at c for each digit interval If this occurs, the pulse is gated to the output lead 16, during the first digit interval of the next number, by a pulse from b applied to AND circuit 25 This circuit thus requires that 70 each digit interval be filled before a pulse can be gated to the output lead As this only occurs, for the case of n= 4, when the binary half-adder has counted up to 2 ', i e, 16, an output pulse is gated only once every sixteen 75 words or once for every sixteen input pulses which in turn are applied once each word or once each four digits of the clock frequency. In the block diagram of Fig 2, to facilitate the explanation of the logical components of 80 this embodiment of the invention, ideal circuit elements have been assumed in which no amplification of pulses is required and all delay incurred in the circuit occurs in the delay lines, the other circuit elements not introducing any 85 delay In fact, however, amplification is required and the other elements do introduce delay so that the delay lines depicted in Fig 2 must be modified and compensatory delay lines added to take account of this introduced delay 90 and keep the circuit components in synchronism Fig 4 a is a revised block diagram in which the amplifiers and compensatory delay lines have been added and the delay of the previously mentioned delay lines modified to 95 take account of the delay inherent in the amplifiers The delay introduced by the amplifiers is, at the clock frequency employed in this embodiment, substantially one quarter digit, and amplifiers 30 are positioned in the first 100 stage frequency divider 11, the half-adder circuit 19, between delay line 21 and the halfadder 19, between delay line 26 and AND circuit 25 and in the output lead 16 Accordingly, the delay of lines 22 and 26 is reduced by one 105 quarter digit and of delay line 21 by three quarters digit; the delay loop of delay line 21 includes two amplifiers 30 and the compensatory delay line 38 referred to below, so that the total delay of the loop is 4 digits Half 110 digit compensating delay lines 32 are included in the paths from the first

stage frequency divider 11 to the OR circuit 28 and the AND circuit 25; delay lines 32 delay pulses from circuit 11 the equivalent of the delay of the 115 pulses to the other input leads of these circuits, which delay is introduced by the two amplifiers through which these other pulses pass. The binary half-adder may advantageously 120 comprise an OR circuit 35, and AND circuit 36, and an inhibitor 37, together with a pair of amplifiers 30 and a one-quarter digit compensatory delay line 38. The first stage frequency divider may com 125 prise a delay line register As seen in Fie 4 a, the circuit comprises an OR circuit 40, an amplifier 30, a delay line 41, and a compensatory delay line 42 Delay line 41 serves to introduce N digits of delay to pulses from the -130 OR circuit output back to the OR circuit input In this specific embodiment the delay line 41 has one and three-quarter digits of physical delay but is terminated in a short circuit so that pulses of opposite polarity are reflected back to the input; accordingly, a positive pulse is applied to the delay line 42 three and onehalf digits later The total delay between the output and input of the OR circuit 40 is thus four digits, comprising the one-quarter digit introduced by the amplifier 30, the three and one-half digits introduced by the delay line 41 and the one-quarter by the delay line 42. Advantageously, the negative pulse from the amplifier 30 which is reflected by the delay line 41, as a positive pulse, is not applied to delay line 42 due to the interposition therebetween of a diode 43, seen in Fig 4 b. The amplifier circuits may advantageously be of the transistor regenerative type A suitable circuit which is depicted in the amplifier for the divider 11 in Fig 4 b, includes an output transformer having its primary winding connected to the collector of the transistor and at least a pair of secondary windings, one of which is a feedback winding and the other of which an output winding for positive output pulses If a negative output pulse is desired, as in the amplifier 30 of the divider 11 and the amplifier 30 connected to the inhibitor 37 in the half-adder 19, a third output winding is provided and wound in the opposite direction to produce a negative pulse. The clock frequency is advantageously applied to the emitter of the transistor, as shown in Fig 4 b In this specific embodiment a four phase clock is employed, the phases being identified on the drawing as A, B, C, and D, and being one-quarter digit or 90 degrees of the clock frequency apart The clock frequency in this embodiment is three megacycles and the delays of the various delay lines in Fig 4 b are noted in microseconds in the drawing.

Each of the OR and AND logic circuits advantageously comprises a pair of diode elements, such as varistors, biassed to enable passage therethrough of only positive pulses in the forward direction as is known in the art Each of the delay lines may comprise inductive members and capacitances, as is also known in the art One particular type of delay line that may be employed comprises coils wound on an insulating rod with button condensers connected between a turn of each coil and ground; such a delay line is shown at page 214 of the book " Components Handbook ", J F. Blackburn, Ed (M I T Radiation Laboratory Series, Volume 17, 1949). In the above discussion it has been assumed that the delay in the first divider stage is n digits and that the accumulation in the second divider stage is also N digits; this accumulation in the second stage is the delay between the sum output of the half-adder circuit and the input thereto and is indicated by element 13 in Fig 1 It represents the storage or accumulation capacity of the second stage of frequency division However, it can be seen that these two periods of delay need not be the same but may be related to each other by a constant k, which may be any positive integer The frequency division attainable for the possible combination is then:Delay of Delay of Resultant divider 11 line 13 Frequency Division n N 1/(n) ( 2 ") kn N 1/(kn) ( 2 a) If N is a large number it may be difficult and unwieldy to employ a single short-circuited delay line in the delay line register of the first 80 stage of frequency division Two such circuits, as depicted in Fig 5, may be employed together with an AND gate 45, the upper circuit including a short-circuited delay line 4 ly having a physical delay of y/2 digits and thus 85 introducing a delay of y digits into the circuit and the lower circuit including a short-circuited delay line 41 x having a physical delay of x/2 digits and thus introduced a delay of x digits into the circuit; the amplifiers 30 are 9 o here asumed to introduce no delay If x and y are relative primes, then the resultant frequency division is 1/(x)(y) of the base frequency However, whether they are relatively prime or not, the resultant frequency division 95 is equal to the least common multiple of the individual delays In this manner very large frequency divisions are attainable in the first stage; in one embodiment six such circuits having individual fre 100 quency divisions of 1/19; 1/17; 1/15; 1/14; 1/13; and 1/11 were employed and the resultant frequency division was 1/( 19) ( 17) ( 15) ( 14) ( 13) ( 11) or 1/9,699,690 of the clock frequency This is a frequency 105 division of the order of 107 to 1; in one specific embodiment wherein the clock frequency was thre megacycles, an output pulse was provided once every 3 23 seconds It should be noted that the six circuits employed include 110 the numbers containing all the primes less than 20, since 14 and

15 factor as 2 x 7 and 3 x 5. Fig 6 is a block diagram presentation, again assuming ideal circuit elements, of another specific illustrative embodiment of this inven 115 tion In the embodiment of this invention depicted in block diagram form in Fig 2 very large frequency divisions are possible, but not all desired frequency divisions are attainable. This is because the frequency division is 1/(n) 120 ( 2 n) the clock frequency: In the embo iment depicted in Fig 6 all possible frequency divisions of the word frequency or of the input to the second state circuit may be attained by presetting a number A into the second stage 125 frequency divider so that the frequency division attainable is 1/(n) ( 2 "-A) the clock frequency. 785,568 785,568 In the embodiment of Fig 6 the initiating pulse from the single pulse generator 10 is applied to the first stage frequency divided 11 and also, through an OR circuit 50 to a number or word generator 51 As will be recalled from Fig 3, the first pulse output from the frequency divider 11 is delayed by one word interval after the application of the initial pulse During that first word interval the word or number placed in the word generator is preset into the second stage frequency divider. The word generator may be of any known configuration, but depicted in the drawing comprising (n-1) one digit delay lines 53 each connected through a diode 54 and an manually operable switch 55 to a common lead 56 The initial pulse is passed through the delay lines in succession and appears on the common lead 56 in those digit slots for which the switches 55 are closed. This number is then present into the halfadder 19 of the second stage frequency divider through an OR circuit 186, similar to the OR circuit 18 of the prior embodiment, during the word interval before the application of the first pulse from the first stage frequency divider 11. The second stage frequency divider then accumulates pulses in the delay line 21 as described before, but the accumulation will be finished A pulses earlier due to the number A having been preset into the circuit The output pulse appearing on the output lead 16 is fed back through the OR circuit 50 to the number generator 51 to preset the number A into the second stage frequency divider at the beginning of the second cycle of operation and is also applied to an inhibitor circuit 58 to inhibit the pulse from the first stage frequency divider 11 while the number A is being preset into the second stage circuit A may be any number from 0 to 2 "-1. As mentioned above the block diagram of Fig 6 only depicts the logic elements and assumes them to be perfectly lossless and delayless Actually each delay line 53 would have associated therewith a

transistor amplifier and, if the clock frequency is three megacycles be of only 3/4 digit delay to compensate for the one-quarter digit delay of the transistor amplifier. For some applications it is desired not to have a single output pulse from the frequency divider but a train of pulses occurring for onehalf the cycle of the output frequency of the circuit This is particularly the case if it is desirede Fto pass the pulses through a low pass filter to'reconstruct a low frequency sine wave. Anothe P illustrative embodiment of this invention is depicted in Fig 7 wherein the output is a train of pulses occurring once every digit for the first half of the cycle of the low frequency output of the second stage frequency divider. These pulses provide essentially a square wave which, when passed through a low pass filter, can give the desired sine wave. An understanding of the operation of this embodiment can be gained from a consideration of the time-phase chart of Fig 8 The circuit depicted in Fig 7 includes the elements of the embodiment of Fig 2 and a portion of 70 the time chart of Fig 3, applicable to both embodiments, is repeated in the time chart of Fig 8 It should be noted, however, that the first line of the time chart of Fig 8 is the pulse output at point 1 This pulse is applied 75 directly to one input of a memory cell comnprising an OR circuit 60, a one digit delay line 61, and an inhibiting circuit 62 The pulse immediately appears at the output point q of the memory 80 cell and circulates in the memory cell, reappearing at q at each digit time or cycle of the clock frequency The memory cell thus serves initially as a continuous pulse source. To stop this pulse train by turning off the 85 memory cell after theone-halfcyclehaspassed, an inhibiting pulse is applied to the inhibitor 62 at precisely the middle of the cycle. This inhibiting pulse is derived from a gate circuit comprising the one digit delay line 26, 90 an inhibitor 64, a one digit delay Ine 65, and an AND circuit 66 The one digit delay line 26 and the inhibitor 64 serve as a selector circuit letting only the last pulse of a train, appearing at point h, appear at point m, delayed 95 by one digit The pulse at point m is passed through the one digit delay line 65 and applied, at point o, to one input of the AND circuit 66 As will be recalled, a pulse train appears at point h only if a pulse occurs at c 100 in synchronism with a pulse at b Thus only those pulse trains corresponding to numbers having a pulse in the first digit interval enter this gating circuit Additionally the other input of the AND circuit 66 is also the pulse 105 from point b Therefore the output of the AND circuit 66, at point p, is a pulse at the start of a word or number interval when the prior number, at point c, had a pulse at the

first digit space and sufficient digits so that the 110 last digit, delayed by two digit intervals, occurs at the first digit interval of the next number. The time chart of Fig 8 shows that this occurs only after the number " 7 " has been counted by the half-adder 19, so that a pulse only 115 appears at p at the start of the eighth number interval This however, is precisely the halfcycle point of the output of the frequency divider in this embodiment The pulse at p is applied to the inhibiting lead of the inhibi 120 tor 62 to turn off the memory cell and stop the train of digit pulses appearing at point q. In the above-described embodiments it has been assumed that the first stage of frequency division is triggered on application thereto of 125 a single initiating stage of frequency division to which is applied, from a clock frequency source 70, a train of clock pulses These pulses are applied to an inhibitor circuit 71 on one input lead 72 thereof; the first pulse applied 130 785,568 appears also on the output lead 73 and is applied to the second stage of frequency division as described above. The output pulse, however, is also applied to the inputs of N parallel delay lines 75 having delays of from 1 digit time of the clock frequency to (n-1) digit times, inclusive The outputs of the delay lines 75 are all applied to the other input lead 76 of the inhibitor circuit 71 and prevent the appearance on the output lead 73 of a pulse for the next (n-1) digit times in accordance with the known manner of operation of inhibitor circuits Accordingly a pulse appears at the output lead 73 of the first stage of frequency division only once every N cycles of the clock frequency, and the circuit accordingly attains a frequency division of n/i. The delay lines 75 connected in parallel are, in effect, a pulse train generator Other types of pulse train generators may be connected between the output lead 73 of the inhibitor circuit 71 and the input lead 76 thereof. In Fig 9 idealized circuit elements havagain been assumed It is to be understood, however, that amplifiers, having certain inherent delays, would be utilized If these amplifiers are clocked, as disclosed in the prior figures, at the clock frequency of the circuit, then the initiating signal applied from source at each cycle of the clock frequency need not comprise a train of pulses but may actually be a direct current voltage.

* Sitemap * Accessibility * Legal notice * Terms of use

* Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785569 (A)

Description: GB785569 (A) ? 1957-10-30

Improvements in rotary feeders for positive pressure pneumatic conveyorsystems


COMPLETE SPECIFICATION. Improvements in Rotary Feeders for Positive Pressure Pneumatic Conveyor Systems. We, HENRY SIMON LIMITED, a British Company, of Bird Hall Lane, Cheadle Heath, Stockport, Cheshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to rotary feeders as used in positive pressure pneumatic conveying equipment for the transference of pulverulent material from hoppers, separators or processing machines to ducts along which the material is to be conveyed pneumatically and is particularly directed to the sealing means whereby pressure loss at rotor shaft seal housings is prevented. In rotary feeders, rotor shaft housing pressure retaining seals of various types suitable for internal pressure retention during the feeding of most types of pulverulent materials are well known but there is a group of such materials, for instance sugar or portland cement, which when in contact with the sliding surfaces of relatively moving elements cause considerable increase in the friction generated at such surfaces, giving rise in the case of rotary feeders, where operational pressure tends to force the material into the sealing means, to rapid deterioration, seizure and destruction of said known types of pressure retaining seals and consequent pressure loss and material leakage from the system.

The object of the present invention is to provide in positive pressure pneumatic conveying equipment for the conveyance of sugar, portland cement and like materials, rotary feeders having at each rotor shaft seal housing an improved form of sealing means which will avoid the above disadvantages. The invention consists in a rotary feeder pneumatic pressure conveying equipment in which the ends of the rotor shaft pass through sealing means in the end walls of the rotor casing, each end wall having therein beyond the - aperture through which the shaft passes a recess or cavity into which material which may pass through said aperture can accumulate, the wall of the recess or cavity opposite to the apertured wall comprising a resilient washer having a part thereof which surrounds and extends axially along the shaft into the recess or cavity, so that such material will press upon said part and ensure its intimate sealing contact with the shaft. There may be beyond each resilient washer, a sealing washer to prevent the ingress from exterior sources of oil, water or other liquid or solid material which could adversely affect the sealing function of the resilient washer, the said sealing washer being protected from the material in the cavity by the action of the resilient washer. The invention further consists in a rotary feeder as aforesaid in which the resilient washer which forms a wall, of each recess or cavity around the shaft comprises a part of cylindrical shape which extends coaxially along and in sealing contact with the shaft and a part of radial disc like form which is clamped to the end wall by an assembly comprising a gland plate, a metal ring, a sealing washer which makes intimate contact with the shaft, and a further metal ring, the assembly being secured in place by bolts and nuts. Referring to the accompanying explanatory drawings:- Figure 1 is a longitudinal sectional elevation on the line A B of Figure 2 and Figure 2 a cross-sectional view on the line C D of Figure I showing a rotary feeder with retaining seals for the rotor shaft constructed in one convenient form in accordance with this invention Figure 3 is a detail sectional view drawn to a larger scale than Figure 1 showing one of the retaining seals for the rotor Shaft. The rotor comprises a shaft a having strips b secured in longitudinal slots in the shaft and flexible blades c secured to the strips b. The rotor revolves in a casing d which has an inlet branch at e for the material to be delivered by the rotor. There are pockets f between the blades c and such pockets carry the material from the inlet branch at e to the lower portion of the casing d, when the pockets in succession come into alignment with inlet and outlet branches g and h

respectively, the branch g introducing compressed air to the pockets in succession which blows the contents of the pockets into the branch h which is connected to the conveying system. The aperture dl in the casirig is for releasing the air pressure in each pocket before it arrives at the filling position beneath the feed branch e. The rotor shaft ends i pass through coaxial holes j in the walls of the casing, these holes leaving a generous clearance around the shaft The walls are relatively thin and tapered at the said holes Z and the holes lead to coaxial recesses or cavities k in the walls around the shaft. The wall of each recess or cavity k opposite to that containing the hole j is provided by a resilient washer m made of leather or like material having a tubular part which extends coaxially around the shaft and a part which extends radially around the shaft. The tubular part makes intimate contact with the shaft and the complete washer is held in place by an assembly, comprising a gland plate n, a metal ring a a resilient compressed washer p which may be made of felt and which makes intimate contact with the surface of the shaft end t, and a further metal ring q. The assembly is secured in place by bolts and nuts in the usual manner. In operation, a small quantity of the material passes from the pockets between the blades c through the holes j around the shaft ends i into the recesses or cavities k, which results in the production in each recess or cavity of a ring of the material which presses upon the part of the washer m which surrounds and makes intimate contact with the shaft and ensures that such part of the washer makes sealing contact with the shaft and effectively prevents infiltration of such material into the felt or like washer p and the cylindrical surface of such washer p around the shaft. The material in each cavity k in addition to holding the part of the washer nt which is coaxially around the shaft in intimate contact with the latter also provides for the washer m a protective barrier due to the fact that the material in contact with the stationary walls of the cavity adheres firmly thereto and the material in contact with the rotating shaft i adheres to the surface thereof and rotates with it, inducing within the rest of the material in the cavity a confused particle motion and providing a resistance to the ingress of additional material to the cavity, thus protecting the washer nt from the effects of undue pressure. Such material remains confined in the recess or cavity and does not change. What we claim is : - 1. A rotary feeder for pneumatic pressure conveying equipment in which the ends of the rotor shaft pass through sealing means in the end walls of the rotor casing, each end wall having therein beyond the

aperture through which the shaft passes, a recess or cavity into which material which may pass through said aperture can accumulate, the wall of the recess or cavity opposite to the apertured wall comprising a resilient washer having a part thereof which surrounds and extends axially along the shaft into the recess or cavity, so that such material will press upon said part and ensures its intimate sealing contact with the shaft. 2. In a rotary feeder as claimed in Claim 1, the provision beyond each resilient washer of a sealing washer which makes intimate contact with the shaft and is protected from the material by the action of said resilient washer. 3. A rotary feeder as claimed in Claim 1 or 2, in which the resilient washer which forms a wall of each recess or cavity around the shaft comprises a part of cylindrical shape which extends coaxially along and in sealing contact with the shaft and a part of radial disc like form which is clamped to the end wall by an assembly, comprising a gland plate, a metal ring, a sealing washer which makes intimate contact with the shaft and a further metal ring, the assembly being secured in place by bolts and nuts. 4. The improved rotary feeder for pneumatic pressure conveying equipment substantially as described and as illustrated.

* GB785570 (A)

Description: GB785570 (A) ? 1957-10-30

Functional fluids

Description of GB785570 (A) Translate this text into Tooltip



PATENT SPECIFICATION 785,570 i) Date of Application and filing Complete Specification Sept 22, 1955. No 27068/55. Application made in United States of America on Sept 23, 1954. Complete Specification Published Oct 30, 1957. Index at Acceptance: -Class 69 ( 2), P 12. International Classification: -FO 3 c. COMPLETE SPECIFICATION Functional Fluids We, MONSANTO CHEMICAL COMPANY, a corporation organised under the laws of the State of Delaware, United States of America, of 1700, South Second Street, City of St. Louis, State of Missouri, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to functional fluid compositions and more specifically to hydraulic mineral oil compositions having particularly useful viscosity-temperature relationships These compositions are especially suited for use in aircraft hydraulic systems, and similar uses where hydraulic fluids are required to have outstanding low temperature viscosity properties. According to the present invention there is provided a functional fluid comprising (a) a mineral base oil having a pour point not higher than -70 F, a flash point not lower than 1800 F, and a viscosity not greater than 12 centipoises at 1000 F and (b) a copolymer of (i) at least one alkyl acrylate having 8 to 10 carbon atoms in the alkyl group and (ii) methyl and/or ethyl acrylate, the copolymer having an average of from 5 5 to 7 carbon atoms in the alkyl groups and a molecular weight such that the specific viscosity at 770 F of a 2 % by weight solution thereof in toluene is from 0 4 to 1 2, the copolymer being present in an amount sufficient to give a composition having a viscosity of at least 8 centipoises at 1300 F but not greater than 700 centipoises at -40 F. The mineral base oil utilized in the functional fluids of this invention are light mineral oils well known to be useful as functional fluid, and particularly hydraulic oil, bases However, in order to respond effectively to the viscosity index improving additives used in accordance with the present invention the base oil used must be one having a pour point not higher than -70 F, and preferably lower than -75 F, a flash point not lower than 1800 F, and preferably higher than 2000 F, lPrice 3 s 6 J l and a viscosity not greater than 12 centipoises, and preferably less than 10 centipoises, at 50 1000 F. The alkyl acrylate interpolymers must meet three requirements in order

to be satisfactory viscosity index improvers for use in the compositions of this invention: ( 1) they must be 55 derived from at least two different acrylate monomers, each of which is selected with respect to the number of carbon atoms in the alkyl group; ( 2) the relative proportions of the acrylate monomers used in producing the 60 copolymers employed must be such that the average number of carbon atoms in the alkyl groups in the resulting copolymer falls within narrow limits; and ( 3) the molecular weight must be relatively low and within a specified 65 range. ( 1) ACRYLATE MONOMERS The alkyl acrylate copolymers used in accordance with the prpesent invention must be derived from at least one monomeric alkyl 70 acrylate which contains 8, 9 or 10 carbon atoms in the alkyl group and from methyl and/or ethyl acrylate The monomers containing 8, 9 or 10 carbon atoms in the alkyl group may be either n-alikyl acrylates or 75 branched-chain alkyl acrylates or a mixture thereof Examples of suitable acrylates are n-oetyl acrylate, n-nonyi acrylate, n-decyl acrylate, 2-ethylhexyl acrylate, 1,1,3,3-tetramethylbutyl acrylate, 1,3,5-trimethylhexyl 80 acrylate, 2,2,4,4-tetramethylpentyl acrylate and 2,4,6-trimethylheptyl acrylate. ( 2) MONOMER PROPORTIONS The relative proportions of the monomers to be copolymerised should be such that the average number of carbon atoms in the alkyl grouhs in the copolymer will be between 5 5 and 7 0, and preferably between 60 and 6 8. It is contemplated that a mixture of monomers within each group may be used instead of a single individual In such a case, the mixture is considered as a single monomer having a number of carbon atoms in the alkyl group equal to the molar average of the various components of the mixture Thus, if a mixture of acrylic esters made from a mixture of C 8 and C 1, alcohols is to be used, and the mixture contains the C 8 and CID esters in a mol ratio of 2: 1, the mixture would be considered as an acrylic monomer containing 8 67 carbon atoms in the alkyl groups. Examples of suitable acrylic monomer mixtures for polymerization to form copolymers for use in the compositions of this invention are as follows: 85 % by weight of 2-ethylhexyl acrylate and 15 % by weight of ethyl acrylate; % by -weight of ii-cctyl acrylate and 10 ' by weight of methyl acrylate; 80 % by weight of 2-ethylhexyl acrylate and 20 % by weight of ethyl acrylate; 80 % by weight of an acrylic ester of an " oxo " alcohol derived from an isobutylene dimer and 20 % by weight of ethyl acrylate; 85 % by -w eig'ht of itr-decyl acrylate and 15 % by weight of methyl acrylate; 40 % by weight of r-octyl acrylaue, 40 % by weight of wz-decyl acrylae and 20 % by weight of ethyl acrylate. ( 3) MOLECULAR WEIGHT It is extremely difficult to determine the true molecular weight of a polymer, however, the viscosity of a standard

quantity of any polymer in a solvent is a function of the molecular weight of the polymer Consequently, for the purposes of the present invention, the molecular weights of the copolymers used herein will be specified in terms of the specific viscosity at 770 F of toluene solutions containing 2 % by weight of the polymer The molecular weights of the alkyl acrylate copolymers utilized in the compositions of the present invention should be such that the specific viscosity of the aforementioned solutions is from 0 4 to 1 2 and preferably between 0 6 and O 95. The copolymers of the aforesaid alkyl acrylates are usually utilized in the compositions of the invention in concentrations between 3 and %, by weight, and preferably between 5 and % by weight, the exact concentration depending to some extent upon the particular base oil with which the copolymers are to be incorporated -The concentration of the copolymer should be sufficient to give the resulting functional fluid a viscosity of at -least 8 centipoises, and preferably at least 10 centipoises, at 1300 F; however, the concentration should be no higher than that required to give the functional fluid composition a viscosity of 700 centipoises, and preferably 600 centipoises, at -40 F. The following examples illustrate the nature of the present invention and the manner in which it may be carried into effect. EXAMPLE 1 A mixture of 85 grams of 2-ethylhexyl acrylate, 15 3 grams of ethyl acrylate and 1 grams of a refined mineral hydraulic oil base having a viscosity of 3 68 centipoises at 1003 F and 1 35 centipoises at 210 ' F, a pour point below -75 F and a flash point above 2000 F was placed in a glass flask equipped with a stirrer Air was removed from the flask by flushing out with nitrogen and polymerization was nitiated by the addition o 005 grams of benzoyl peroxide After 2.5 hours, a further 0 2 grams of benzoyl peroxide was added The reaction was allowed to proceed for an additional 3 5 hours when a yield of 982 % of copolymer was obtained. The reaction temperature was maintained at 1940 F throughout the reaction by controlled water cooling The molecular weight of the resulting polymer was such that a 2 % by weight solution thereof in toluene had a spccific viscosity of 0 92. 18.7 grams of the foregoing reaction product (including the mineral oil solvent) was mixed with an additional 81 3 grams of the same mineral oil to give a functional fluid composition containing 7 5 % by weight of poiymer in the oil The composition had a viscosity or 99 centipoises at 130 W F and 525 centipoises at -40 F The viscosity index thereof was 229 as compared with an index o O 98.8 for the base oil witnout the acrylate -copolymer viscosity index improver.

EXAMPLE 2 A mixture ot 157 7 grams of 2-ethylhexyl acrylate, 18 2 grams of ethyl acrylate and 263 grams of a mineral oil having the same pro 95 perties as that used in Example 1 was prepared, and 183 1 grams of the mixture was placed in a glass reaction flask equipped with a stirrer Air was removed from the flask with a current of nitrogen and the polymerization 100 initiated by the addition of 0 037 grams of benzoyl peroxide, an additional 0 051 grams of benzoyl peroxide was dissolved in 1 ml of benzene and mixed with the remainder of the monomer-oil mixture After 30 minutes, 105 gradual addition of the remaining monomeroil-catalyst mixture was begun at the rate of 2.6 mil per minute and continued until all of the mixture had been added to the reaction flask After 5 hours an additional O 044 grams 110 of benzoyl peroxide was added to the reaction mass After an additional 1 75 hours, the polymerization had been completed and a substantially 100 % yield of acrylate copolymer obtained The reaction temperature had been 115 maintained at 1760 F throughout the entire reaction by controlled water cooling The molecular weight of the resulting acrylate copolymer was such that a 2 %Do by weight solution thereof in toluene had a specific viscosity 120 of 0 91. 7.5 grams of the foregoing reaction product (including the mineral oil solvent) was mixed with an additional 42 5 grams of the same mineral oil to give a functional fluid composi 125 tion containing 6 %o by weight of polymer in the base oil The composition had a viscosity 785,570 785,570 of 8 25 centipoises at 1300 F and 360 centipoises at -40 F The viscosity index thereof was 245 2 as compared with an index of 98 8 for the bae oil without the acrylate copolymer viscosity index improver.

* Sitemap * Accessibility * Legal notice * Terms of use * Last updated: 08.04.2015 * Worldwide Database * 5.8.23.4; 93p

* GB785571 (A)

Description: GB785571 (A) ? 1957-10-30

Improvements in or relating to pit props


PATENT SPECIFICATION Date of Application and filing Complete Specification: Oct 4, 1955. &g I No 28209155. Application made in Germany on Oct 18, 1954. Complete Specification Published: Oct 30, 1957. Index at acceptance:-Class 20 ( 2), E 2 D 3 C. International Classification -E 2 lld. COMPLETE SPECIFICATION Improvements in or relating to Pit Props We, 'GUTEHOFFNUNGSHUTTE STERIKRADE ARTIENGESELLSCHAFT, of Lipperfeld 1, Oberhausen, Rhld, Germany, a German Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to a pit prop of the type comprising an outer prop member, an inner prop member of trough section slidably received in said outer prop member, and a clamp comprising a clamp frame affixed to the outer prop member, a clamping cam member extending into said trough section and being carried by said clamp frame for pivotal movement in the longitudinal direction' of the prop, and a jaw for transmitting clamping force from said clamping cam member to said inner prop member, the clamping cam member being adapted to be carried along by a downward movement of said inner prop member relative to said outer prop member in such a manner that the clamping force of said clamping cam member is increased, In yieldable pit props it has proved suitable to construct the clamp so that the clamping force exercised by the clamp does not remain constant during the lowering of the upper prop member but increases to Ma predetermined limiting value This can be achieved by means of a clamping cam member which is carried in the clamp for pivotal movement in the longitudinal directioni of the prop and which is carried along by the subsiding inner prop member to increase the clamping force, which is transmitted by a clamping jaw. To limit the increase 'of the clamping force a stop is provided which will retain said clamping cam member when the predetermined limiting value has been reached. In props having a laterally 'open, hollow section member, e g a trough section, which is superior to an entirely closed section because it

has a larger number of friction faces available, the clamping cam member extends M Price 3 s 6 d J laterally into the prop member Previously a special bracket or support was provided in the lower prop member as a stop for the 50 clampiing cam member. It is an object of the invention to improve these prior props so that the clamping cam member will be supported at the end of its downward movement even without a special 55 stop, bracket or the like in the lower prop member so that the clamping force of the clamp cannot increase beyond the predetermined limiting value as the upper prop member subsides 60 This object is achieved according to the invention thereby that the clamping cam member consists of a two-aimed lever, which is supported on a bottom portion of the clamp frame Ai line with the wall of the outer prop 65 mflember and which has an outer lever arm extending into the clamp and adapted to engage the clamp frame. In its abutting position the clamping cam member is supported on the clamp frame 70 above and below As a result a clamping wedge, pivotally supporting the clamping cam, is relieved of forces acting in the longitudinal direction of the prop The ratio of the two lever arms of the clamping cam member may 75 be selected so that the abutment forces to be absorbed by the outer lever arm are as small as possible. The accompanying drawings show some illustrative embodiments and explain further 80 details of the invention. Fig 1 is a longitudinal sectional view of a prop according to the invention. Fig 2 is a transverse sectional view taken on line I Il-I of Fig 1 85 Fig 3 shows the clamping cam member in its initial position, Fig 4 is a modified form of the clamping cam member, and Fig 5 is a transverse cross section of an 90 other construction thereof. According to Figs 1-3 the inner prop member 1 'and the outer prop member 2 are channel sections open on the side facing the 5,571 2,785,571 clamp The clamp frame 3 surrounds the outer prop member 2 and is affixed to the same, e.g 'by welding A clamping wedge 4 is inserted in the clamp frame and bears on the outside on an abutment 5 whereas it engages a clamping cam member 6 on the inside The clamping wedge 4 is cylindrically rounded on both longitudinal sides the abutment 5 and the engaging surface of the clamping cam member 6 in engagement with the wedge 4 being shaped accordingly, so that the clamping wedge 4 and clamping cam member 6 can be inclined and adjust themselves relative to each other. The clamping cam member represents a two-armed lever, whose inner lever arm has a rounded head 6 a engaging the bearing socket of a clamping jaw 7 The latter is fitted between the flanges of the inner prop member 1 and clamps the latter against the outer prop member 2 The outer lever arm 6 b of the clamping cam member extends into the

clamp frame 3 The clamping cam member has a base portion 6 c, which is supported on the bottom of the lock frame 3 in line with the outer prop wall 2 so that the supporting force of the clamping cam member is effective as far as possible only as a compressive force in the wall of the outer prop member 2, not as a bending moment in the lock frame 3. Before the inner prop member 1 begins to subside under the rock load to be carried, the clamping cam member 6 has approximately the position shown in Fig 3 In that position the outer lever arm 16 b of the clamping cam member is spaced from the upper wall of the clamping frame 3 As the inner prop member subsides it carries the clamping or friction jaw 7 along to swing the clamping cam member in the anticlockwise sense. During that shifting of the clam-ping cam member the clamping or friction jaw 7 is pressed with increasing force against the inner prop member 1 Finally the clamping cam member reaches the position shown in Fig 1 during the subsiding of the inner prop member In that position the outer lever arm 6 b of the clamping cam member bears on the clamp frame 3 to prevent a further downward swing of its inner lever arm and a further downward movement of the clamping or friction jaw 7. In this end position the clamping cam member 6 bears on the clamp frame with its inner lever arm 6 b as well as with its base part 6 c, against the load acting vertically downwards on the head 6 a of its inner lever arm. It is important in practice that this final position of the clamping cam member 6 shown in Fig -1 is determined as exactly as possible in dependence on the maximum value admissible for the clamping force of the clamp in each case. To adjust this limiting value the final position of the clamping cam member may be varied if desired, by shims disposed under the base part 6 c and/or over the outer lever arm 6 b. A spring 8, which is inserted in a recess 9 of the clamping jaw 7 and bears on the one 70 hand on the clamping jaws 7 and, on the other hand on a disc 10 is provided to lift the clamping jaw 7 and to return the clamping cam member into its initial position automatically after the wdge 4 has been loosened The disc 75 is affixed, if desired in an adjustable manner, by means of a bolt 11 to a supporting arm 12, which limits the upward stroke of the clamping jaw 7 so as to fix its upper end position The stroke of the jaw 7 could 80 -be varied by adjusting the bolt 12 The return spring 8 may be omitted, if desired, Hand a returning force may be exercised by giving the clamping cam member an overweight on the lever arm opposite to the clamping wedge 85 According to -Fig 4 a sliding jaw 6 c may Abe provided as a support for the base part of the clamping cam member 6 That sliding jaw can

slide on the bottom of the clamp frame 3 during the movements of the clamp 90 ing cam member The upper side of the sliding jaw is formed as a bearing socket so that the clamping cam member can adjust itself on the sliding jaw with the least constraint. A second sliding jaw 6 b corresponding to the 95 base sliding jaw, may be provided as an abutment for the outer lever arm of the clamping cam member The upper sliding jaw may be arranged to provide an overweight for the clamping cam member in such a manner that 100 the clamping cam member wvill; re-erect itself automatically when the clamping wedge 4 is loosened Since the base part 6 c is more heavily loaded than the engaging end of the lever arm 6 b the upper sliding jaw is less essential 105 than the lower one. The constructions illustrated and described are only exemplary embodiments of the invention, which is not restricted to these specific constructions Numerous modifications are pos 110 sible within the scope of the invention For instance, the outer prop member 2 could be a closed tube section It is only essential for the invention that the inner prop member is an open hollow section A trough section in 115 the sense of the invention, is any section open on one side, e g a channel section, I-section or V-section. An I-section may be considered as composed of two channels For this reason the 120 Invention can also be applied to it, as is showan in Fig 5 The clamping cam member 6 engages on one side the section web, which bears on the other side against an abutment 13 incorporated in the clamp frame 3 Such a 125 special abutment would not be necessary, e g, for a channel section.


* GB785572 (A)

Description: GB785572 (A) ? 1957-10-30

A method and apparatus for continuously applying a protective coating to

metal coated strip


A high quality text as facsimile in your desired language may be available amongst the following family members:

BE542953 (A) FR1147439 (A) BE542953 (A) FR1147439 (A) less Translate this text into Tooltip



PATENT SPECIFICATION 785,572 Date of Application and filing Complete Specification Oct 18, 1955. No 29673/55. Application made in United States of America on March 23, 1955. Complete Specification Published Oct 30, 1957. Index at Acceptance:-Classes 2 ( 5), R 1 C( 6: 7: 8: 12: 16); 2 ( 6), P 1 A, P 1 C( 5: 6 B: 8 B: 8 C: 13 A: 14 A: 14 B: 20 B: 20 C), PID(IB: 5); 39 ( 3), H( 2 D 1 B: 3 C); and 140, K 3 D. International Classification: -B 05 CO 8 f, g H 05 b. COMPLETE SPECIFICATION A method and Apparatus for Continuously Applying a Protective Coating to Metal Coated Strip We, WHEELING STEEL CORPORATION, a Corporation organised under the laws of the State of Delaware, United States of America, of Wheeling, West Virginia, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to continuously applying a protective coating to metal-coated strip It relates to an improvement in the continuous application of a protective coating to metal-coated strip whereby the efficiency of the operation is greatly improved and a superior and more uniform product is produced. While our invention is applicable to the continuous application of a

protective coating to metal strip coated with various metals such as spelter (galvanized), terne, tin, aluminium, etc, our invention has perhaps found its most common use in the continuous application of a protective coating to galvanized steel strip, and for purposes of explanation and illustration the invention will be described in connection with the continuous application of a protective coating to galvanized steel strip. It is known to those skilled in the art that galvanized steel is subject to a non-uniform discoloration sometimes called " wet storage stain " which occurs when galvanized steel is stored in wet or damp condition or in humid atmosphere To obviate wet storage stain it has heretofore been proposed to apply to galvanised steel a protective coating which is applied in liquid form and subsequently dried. Th, protective coating may be a plastic or non-plastic material or a mixture thereof which is applied in a very thin coating or film It may be dried simply by evaporation of solvent or by polymerization, or both if the protective coating material contains both polymerizable and non-polymerizable materials Examples of materials which may be used for the formation of a protective coating on metal-coated strip are: THERMOPLASTIC. Per cent. Formula No 1 by weight Polyvinyl butyral 4 65 Polymerized rosin 4 65 Isobutyl alcohol 4 78 Acetone 5 69 Isopropanol ( 99 %) 79 44 Water 32 Phosphoric acid ( 85 %); 32 Chromium trioxide 15 00 Formula No 2 Polyvinyl butyral 8 84 Isobutyl alcohol 3 99 Acetone 9 82 Ethyl alcohol 75 86 Water 61 Phosphoric acid ( 85 %) 61 Chromium trioxide 27 00 Formula No 3 Polymerized rosin 5 00 Ethyl alcohol 82 93 Polyvinyl butyral 4 42 Isobutyl alcohol 2 00 Acetone 4 90 Water 30 Phosphoric acid ( 85 %) 30 Chromium trioxide 15 00 THERMOPLASTIC AND THERMOSETTING (PREDOMINANTLY THERMOSETTING). Formula No 4 Polyvinyl butyral 3 75 Phenolic resin 2125 Isopropanol ( 99 %) 7125 Isobutyl alcohol 3 75 00 THERMOPLASTIC AND THERMOSETTING (PREDOMINANTLY THERMOPLASTIC). Formula No 5 Phenolic resin 2 5 Isopropanol ( 99 %) 5 6 Butyl alcohol 4 Isobutyl alcohol 4 O Toluol 1 4 Polyvinyl butyral 8 O Acetone 8 8 Ethyl alcohol 68 1 Water 5 Phosphoric acid ( 85 %,o) 5 Chromium trioxide 2 100 0 THERMOSETTING. Formula No 6 Phenolic resin 25 O Isopropanol ( 99 %) 56 25 Butyl alcohol 3 75 Toluol 15 00 10000 Difficulty has heretofore been experienced in the continuous application of a protective coating to metal-coated strip due to the necessity of rendering the protective coating material substantially dry before it is contacted by any portion of the apparatus following the protective coating material applying means If the protective coating material is contacted by any

portion of the apparatus while it is wet the uniformity of the protective coating is interfered with and inferior product is produced It is desirable to effect the application of the protective coating material in a high speed continuous operation and in order to dry the protective coating material before it is contacted by any portion of the apparatus following the protective coating material applying means it is necessary either to pass the strip through a great distance while it is being dried and before it is contacted by any portion of the apparatus following the protective coating material applying means, which is highly undesirable, or to apply a great amount of heat. But a continuous protective coating applying line, like any other continuous line, is subject to slowdowns and stoppages, and when slowdowns and stoppages occur there is danger that the heat applied to dry the protective coating material may burn the protective coating material or indeed even melt the metal coating on the strip. We have devised a method and apparatus overcoming the disadvantages of prior methods and apparatus for continuously applying a protective coating to metal-coated strip We have found that superior results are obtained by drying the protective coating material by electric induction heating Not only is electric induction heating highly efficient but it is subject to instant and close control which adapts it particularly for use in a continuous line for applying a protective coating to metalcoated strip The magnitude of electric induc 65 tion heating can be altered instantly so that when the strip slows down or stops the heat applied to the strip may be simultaneously proportionately reduced or shut off entirely That may be accomplished by a suitable rheostat in 70 the electric induction heating circuit The rheostat may be manually or automatically operated The operation of the rheostat may be controlled in relation either to the temperature of the protective coating material being dried 75 or to the speed of advance of the strip since the speed and temperature bear direct relation to each other We find it desirable to couple the rheostat to a variable speed line drive motor for advancing the strip so that the magnitude 80 of the electric induction heating is maintained proportional to the speed of the motor and hence to the speed of advance of the strip. Alternatively the rheostat may be operated from a thermocouple or other heat sensitive 85 device reflecting the temperature of the protective coating material being dried Thus we maintain at all times the proper magnitude of drying heat so that when the strip slows down or stops the protective coating is not burned 90 and the metal coating on the strip is not melted It is not possible to maintain such a control using any other method of applying heat to dry the protective

coating material. We produce a superior and unprecedentedly 95 uniform product in a highly efficient and economical manner. We provide a method of continuously applying a protective coating to metal-coated strip comprising advancing thb strip, during such 100 advance applying to the strip a protective coating material which is in liquid form as applied and thereafter and while the strip continues to advance heat treating the protective coating material by electric induction heating and 105 thereby rendering the protective coating material substantially dry before it is contacted by any portion of the apparatus following the protective coating material applying means. We control the magnitude of the electric induc 110 tion heating in accordance with the speed of advance of the strip to insure rendering the protective coating material substantially dry before it is contacted by any portion of the apparatus following the protective coating 115 material applying means without deleterious overheating. We prefer to continuously treat strip by continuously advancing the strip through a metal coating station and a; that station applying 120 metal coating material to the strip, as the strip continues its advance applying to the metalcoated strip a protective coating material which is in liquid form as applied, thereafter and while the strip continues to advance heat treat 125 ing the protective coating material by electric induction heating and thereby rendering the -2 785,572 785,572 protective coating material substantially dry before it is contacted by any portion of the apparatus following the protective coating material applying means and controlling the magnitude of the electric induction heating in accordance with the speed of advance of the strip to insure rendering the protective coating material substantially dry before it is contacted by any portion of the apparatus following the protective coating material applying means without deleterious overheating, although we may apply the protective coating material to strip which has previously been galvanized or coated with other metal and coiled Continuous lines for applying metal coatings to strip, notably steel strip galvanizing lines, have recently attained unprecedentedly high speeds The only practicable way of applying to strip in a single continuous line a metal coating and a protective coating over the metal coating without intermediate coiling of the strip is by the use of electric induction heating for drying the protective coating material It is preferable that the control of the magnitude of the electric induction heating be effected automatically as explained above but it is possible to effect the control manually if desired. The protective coating material is preferably applied by rollers The

applying rollers may receive liquid coating material from other rollers partly immersed in liquid coating material similarly to the application of ink to the form in a printing press We have found that the protective coating material can be applied more evenly and its thickness more closely controlled when applying rollers are used than when the protective coating material is otherwise applied The protective coating material is applied in an extremely thin coating or film and the requisite uniformity of such a thin coating, particularly in a high speed line, can be most effectively maintained through application of the protective coating material to the strip by rollers. Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof and a present preferred method of practicing the same proceeds. In the accompanying drawing we have shown a present preferred embodiment of the invention and have illustrated a present preferred method of practicing the same in which the single figure is a diagram illustrating one form of apparatus for carrying out our invention and one method of practicing the invention which may be employed. The strip being pcoated is designated by reference numeral 2 The drawing illustrates a continuous metal-coating and protective coating line which will be deemed to be a continuous steel strip galvanizing and protective coating line All of the elements of the apparatus are shown purely diagrammatically as their detailed construction will be understood by those skilled in the art. The strip passes downwardly about a roll 3 immersed in molten spelter 4 in a galvanizing pot 5 The strip moves horizontally in the gal 70 vanizing pot and then about a roll 6 and up out of the molten spelter 4 between exit rolls 7 The galvanized strip in its upward movement passes through a cooling duct 8 It thereafter passes about a roll 9 and thence hori 75 zontally through another cooling duct 10 to another roll 11 The galvanized strip at the proper temperature for application of the liquid protective coating material passes downwardly from the roll 11 between protective go coating material applying rollers 12 which receive liquid protective coating material from rollers 13 partly immersed in baths 14 of liquid protective coating material at opposite sides of the strip It should be explained that although 85 the liquid protective coating material is shown as being applied to the strip as the strip moves vertically downwardly such material may be applied to the strip while the strip is moving upwardly or horizontally or in any other direc 90 tion We prefer to apply the liquid protective coating material to the strip while the strip moves downwardly because application in that manner facilitates control of

the thickness of the coatings applied to the opposite sides of 95 the strip When the strip is moving horizontally the control of the thickness of the coatings applied to the top and bottom surfaces thereof so that such coatings will be of equal thickness is much more difficult 100 The coating material applying rollers 12 are preferably driven at a peripheral speed which is at all times equal to the speed of advance of the strip This results in the proper thickness of protective coating material being 105 applied to each face of the strip at all times during the operation even though the strip may slow down or stop from time to time. From the liquid coating material applying means the strip moves straight downwardly 110 as shown and is dried before the protective coating material is contacted by any portion of the apparatus following the rollers 12 The strip with the liquid protective coating material thereon passes through an electric induction 115 heating coil 15 which applies to the strip through induction as known to those skilled in the art heat which in our process is effective for drying the protective coating material and for polymerizing any portion of the protective 120 coating material which may be polymerizable. From the electric induction heating coil 15 the strip passes downwardly and is sprayed by water sprays 16 and passes about a roll 17 partly immersed in a bath of water 18 in a 125 water tank 19 The strip thence passes between squeegee rolls 20 and through a drier 21 and about driving rolls 22 which supply the motive power for advancing the strip through (the apparatus The strip thence passes to a shear 130 785,572 to be sheared into sheets or to a reel for coiling The rolls 22 are driven by the previously mentioned variable speed line drive motor (not shown). The speed of the variable speed line drive motor which drives the rolls 22 is at all times proportional to the speed of advance of the strip The circuit for the electric induction heating coil 15 includes a high frequency generator 23 which may be driven by any suitable source of power and whose field winding is designated diagrammatically at 24 The field winding 24 of the high frequency generator 23 is in series with a suitable power source designated generally by reference numeral 25 and a rheostat designated generally by reference numeral 26 which has a resistance element 26 a and a movable contactor 26 b The movable contactor 26 b of the rheostat 26 may be moved along the resistance element 26 a by means controlled by the speed of turning of the variable speed line drive motor which drives the rolls 22 The operative connection between the variable speed line drive motor and the movable contactor of the rheostat is designated generally by reference numeral 27 and may comprise mechanism well known to those skilled in the art so that it is unnecessary to illustrate and

describe in detail such mechanism. The rheostat controls the magnitude of current in the induction coils in proportion to the speed of the strip The same result may be accomplished by controlling the rheostat by the temperature of the strip between the induction coils The rheostat may be operated manually instead of automatically. Thus when the strip slows down or stops the current to the induction coils is reduced or shut off, the effect on the strip being instantaneous, which is not true with any other type of heating In a heating chamber even though the source of heat may be shut off the strip is still subject to the established temperature in the chamber until the chamber has time to cool Our method is foolproof; the protective coating is not burned and the metal coating is not melted A product of high quality and unprecedented uniformity is produced.


Law

5161 5165.output