C-Valve Sizing Guide

Clarkson C-Valve Sizing Guide

Sizing Guide for the Clarkson C-Valve, the Only Slurry Throttling Valve

C-Valve Described The C-Valve consists of an elastomer sleeve, available in various materials, surrounded by an elastomer muscle, inside a cast ductile iron body housing. To throttle the slurry flow, the muscle is compressed inward by hydraulic pressure, reducing the orifice size of the sleeve in a 360-degree squeeze. As it constricts, a round and concentric aperture is maintained across the entire throttling range, from wide open to 50% reduction in diameter. This equates to a 75% reduction in open area or up to 90% reduction of maximum flow. Its closure pattern provides modified linear control. Various sleeves are available to suit applications in size and media The standard C-Valve sleeve orifice is full port in the wide-open condition; however, many times a reduced port is better suited to the application. Optional reduced-port sleeves are available to change the size of the orifice. They are inexpensive, easily installed and give the user the flexibility of varying the valve size to meet changing conditions. Additionally, in applications where the exact process conditions are not initially known, a smaller bore reducing sleeve valve can be installed to correct inadvertent oversizing. See page 2 for optional sleeve sizes.The sizing information contained within is intended to allow the user to determine the proper combination of valve and sleeve size to meet the process requirements.

Table of Contents:Title Introduction Method Example 1, Lime Feed Control Example 2, Pumping System, Flow Control Example 3, Static Head Thickener Underflow Nomograph for Friction Loss Representative Equivalent Lengths in Pipe Diameters Pulp Determinations Nomographic Chart for Maximum Velocity Typical Slurry Pump Performance Curves Sizing Curves, 1 - 12 C-Valve Sizing Input Data Pipe Elevation and Configuration Diagram Page 2 2 3 4 6 9 10 11 12 13 14 23 24

Tyco reserves the right to change product design and specifications without notice. Copyright 2001 by Tyco International Ltd.

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Clarkson C-Valve Sizing GuideIntroduction

Introduction

Method

The data presented in the sizing curve section follows standard conventions of the control valve industry. All of the values pertain to the performance of the C-Valve in water at 60F [15.6C], and in the given pipeline size. The C-Valve is designed to operate from full open to 75% port area reduction, or a reduction of 50% in the port diameter. This will be referred to as Operating Range in the sizing curves. There are several combinations of valve/sleeves that can be operated over a wider range. The C-Valves round port remains circular from full open to a 50% reduction in diameter. In general, the valve characteristic for a C-Valve is linear or modified linear. There are some combinations of valve/sleeve that deviate from this pattern. The Cv curves presented later in this publication illustrate the flow characteristic for all C-Valves. The sleeve is the replaceable elastomeric wear component of the C-Valve. A wide variety of elastomers are available for many applications. Generally, the elastomers are selected depending on three main considerations, abrasion, chemical, and temperature resistance. Other considerations are the process pressure, and the type of control desired. Wear and permanent set, in the elastomeric sleeve of the C-Valve, can change the flow characteristics from the original conditions. The controller can be readjusted if required to compensate, or if desired, the valve sleeve can be replaced to attain the original design start point. Another important factor in slurry flow control is fluid flow velocity. This velocity is very dependent on the settling velocity. This is the minimum velocity required to keep the solid particles from settling to the bottom of the pipe/valve. The graph on Page 12 may be used to estimate this velocity.

The basic sizing method used to determine the required C-Valve flow coefficient is the standard Cv equation: Where: Cv Cv = Q (K) (S.G./ P)

- System flow coefficient

Q - Volumetric flowrate (volume/time); gpm K - Unit correction factor (pressure/gal/min) to make Cv dimensionless (K=1 for gpm & psi units)

P - pressure drop across the valve installation (pressure); psidS.G. - Slurry specific gravity (dimensionless)

The C-Valve that most closely matches the required Cv range of the process is then chosen . In the examples shown on the following pages, all calculations are carried out in U.S. customary units; therefore, K will be omitted in the following examples. For initial data and final results, the metric equivalent is shown in brackets [ ].

Available Sleeve Sizes Valve Size Full Port Reduced Port 1 1x 1x 1x 1x 1x 1x 1 .75 .50 .38 .25 .19 1.50 1.5 x 1.5 1.5 x 1 2x1 3 x 1.50 2 2 2 3 6 x x x x 2 1.50 2 3 3 3 3 4 8 x x x x 3 2.5 2 4 4 4x4 4x3 6x4 6 6x6 6x5 8x6 8 8x8 8x7

Elastomer Sleeve

Sleeve Retainer Elastomer Muscle Ductile Iron Body


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Clarkson C-Valve Sizing GuideExample 1

Example 1, Line Feed Control

Problem: Determine the best C-Valve size and check the flow velocity based on the following data provided from a valve data sheet:

LINE SIZE: 8" Sch. 40 steel pipe [203 mm] FLUID/SLURRY: Lime slurry SPECIFIC GRAVITY MIXTURE (S.G.): 1.15 MAXIMUM FLOWRATE: 2000 gpm [454 m3/hr] NORMAL FLOWRATE: 1500 gpm [341 m3/hr] MINIMUM FLOWRATE: 900 gpm [204 m3/hr] DIFFERENTIAL PRESSURE AT FLOWRATE:

MAXIMUM: 27 psid @ minimum flow [186.2 KPa] NORMAL: 15 psid @ normal flow [103.4 KPa] MINIMUM: 8 psid @ maximum flow [55.2 KPa]

Solution: 1. Calculate the Cv from the equation Cv = (Q) (S.G. / P)

At maximum flowrate and minimum differential pressure, Cv = 2000 (1.15/8) = 758

At normal flowrate and differential pressure, Cv = 1500 (1.15/15) = 415

At minimum flow rate and maximum differential pressure, Cv = 900 (1.15/27) = 186

2. From the Cv chart for an 8" pipeline (Page 21), the 6" CValve with the 6 x 4 reduced port sleeve and a Cv range of about 110 to 1000 is selected. This selection allows for flowrate adjustment in both higher and lower flow ranges. Adjustment could be done with a full port 6 x 6 or reduced port 6 x 5 or 6 x 3 sleeves, without replacing the entire valve. 3. From the nomograph on page 9, the flow velocities in the 8" line are 5.7, 9.5, and 13 ft./sec. [1.74,2.9, 3.96 m/s]. These are all reasonable velocities for a fine particle slurry.


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Example 2, Pumping System Flow Control

Problem: Determine the best pump speed, and valve sizing, to control the system flowrate from 800 to 1400 gallons per minute (gpm). System Parameters:

For the elbows: Le = (20) 0.5 ft. = 10 ft. [3.05 m] 4 elbows = 40 ft. [12.2 m]

Adding these equivalent lengths to the 220 feet [67 meters] of actual 6" pipeline gives the total equivalent pipeline length (TEL) of 273 feet [83.2 m]. From the nomograph on page 9 and a C value of 100 for steel pipe, the following friction loss (f) values can be determined:

TOTAL PIPELINE LENGTH = 220 FT. [67.1 m] 6" SCH 40 STEEL PIPE [152 mm] 2-6, 150# GATE VALVES [152 mm @ 1034 KPa] 4-90 DEGREE LONG RADIUS ELBOWS NET STATIC LIFT REQUIRED = 30 FT. [9.14 m] SPECIFIC GRAVITY OF FLUID = 1.0 TEMPERATURE = 70F. [21.1C] AVAILABLE PUMP, 6 X 4 X 13.5 slurry pump

Solution: In order to draw the system curve and pump performance curves on a flowrate vs. head chart, the following is required: Total equivalent pipeline length

Friction losses at each flowrate Pump performance data

At 300 gpm, f = 1.2 ft. per 100 ft. [0.37 m/30.5 m] of pipeline length. At 600 gpm, f = 4.4 ft./100 ft. [1.34 m/30.5 m] of pipeline length. At 900 gpm, f = 9.5 ft./100 ft. [2.9 m/30.5 m] of pipeline length. At 1200 gpm, f = 16 ft./100 ft. [4.9 m/30.5 m] of pipeline length. At 1500 gpm, f = 22 ft./100 ft. [6.7 m/30.5 m] of pipeline length. At 1800 gpm, f = 34 ft./100 ft. [10.4 m/30/5 m] of pipeline length.

The total equivalent pipeline length is the sum of the actual pipeline length, and the equivalent lengths of all valves and fittings. From Crane Technical Paper #410 (Page 10) the equivalent length expressed in pipe diameters L/D), for the gate valve is 13 and for the long radius 90-degree elbow is 20. Multiplying these L/D numbers, by the pipe diameter (D) in feet, yields the equivalent length (Le) of pipe for each fitting.

Keep in mind that each of the values for f must be multiplied by 2.73 (number of 100 foot intervals in the system) to plot the actual friction head. Example: @ 300 gpm, f = 1.2 (ft./100 ft.) (2.73) = 3.28 ft. Graph #1 (Page 5) is drawn in the following way:

For the gate valves: Le = (L/D) D = (13) 0.5 ft. = 6.5 ft. [1.98 m] 2 valves = 13 ft. [3.96 m]

First, a horizontal line is drawn at 30 feet of water head to show the static head the pump must deliver to raise the level as required between the two tanks (see Figure 1, above).


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Next, the friction (f) values, at each flowrate, are plotted, using the static head line as the zero line. Then the pump performance data (see pump chart included on Page 13) are drawn onto the graph. Use 1550, and 1750 rpm as examples. Vertical lines are then drawn at the desired flowrate values of 800 and 1400 gpm [182 and 318 m3/hr].

Where: Q S.G.

-

Flowrate in gpm Slurry specific gravity (dimensionless)

P

-

pressure drop across the valve installation (pressure); psid

From this equation, the required minimum Cv at 800 gpm [182 m3/hr], and 43.3 psid [298 KPa], is 122; the maximum Cv at 1400 gpm [318 m3/hr] and 15 psid [103.4KPa] is 361. Notice that the maximum Cv is calculated from maximum flowrate and minimum pressure drop, while the minimum Cv is from the minimum flowrate and maximum pressure drop. From the Cv chart for the 6" (Page 20) pipe size, five possible valve/sleeve combinations cover this range of Cv. They are the 4 x 4, 6 x 4, and the 6, 4, 3 all with 3" port. The 4 x 3 is chosen for the following reasons: A) The reduced port sleeve allows better control since the curve has no flat spot that is normally seen in the full port sleeves. B) The 4" valve can be refitted with both larger and smaller ports if adjustment is desirable. C) Though the 6" valve with a 3" reduced port will also control in this application, there is no port smaller than 3" available in a 6" valve. D) Initial cost favors using the smallest valve size possible.

From the Graph #1, the difference in ft. of water between the pump curve and the system friction curve at each desired flowrate is the required pressure drop to be imposed by the C-Valve.

At 1550 rpm, and 800 gpm, the required pressure drop ( P) = 100 ft (0.433) psi/ft. water = 43.3 psid [198 KPa]. At 1550 rpm, and 1400 gpm, P = (35 ft.) (0.433 psi/ft. water) = 15 psid [103.4 KPa]. At 1750 rpm, and 800 gpm, P= (140 ft.) (0.433 psi/ft. water) = 61 psid [420.6 KPa]. At 1750 rpm, and 1400 gpm, P= (75 ft.) (0.433 psi/ft. water) = 33.5 psid [231 KPa].

Since the Clarkson C-Valve is not recommended for pressure drops of greater than 50 psid [344.7 KPa], the pump speed of 1550 is chosen. The maximum calculated pressure drop is only 43.3 psid [298 KPa]. Higher pressure drop can cause cavitation damage. To calculate the required valve flow coefficient (Cv), the equation is: Cv = (Q)(S.G./ P)


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Example 3: Static Head Thickener Underflow

Problem: Determine the proper C-Valve size and select the pipeline size for the following thickener underflow system: THICKENER TONNAGE: 7,000-10,000 tons/day (tpd) [6,350 9,072 metric ton/day] DESIRED UNDERFLOW SOLIDS CONCENTRATION: 50% by weight (wt.) SPECIFIC GRAVITY SOLIDS: 2.60 PIPELINE LENGTH: 160 ft. [48.77 m] REQUIRED FITTINGS: 2 -90 deg. long radius elbow 1 -Clarkson knife gate shut-off valve TOTAL STATIC HEAD: 25 ft. [7.62 m] Solution: 1. Determine the flow rate in U.S. gallons per minute (gpm) and the slurry specific gravity (S.G.) at the desired 50% solids by weight. (Use Nomograph or associated formula, Page 11). From the formula for converting tons per hour (tph) to gpm at 50% solids the flowrate in gpm is: Flowrate = (4.02) (tph) ([% water/% solid] + 1/S.G. solid). Flowrate (At 7500 tpd) = (4.02)(7500/24) ([.5/.5 + 1/2.60]) = 1739 gpm [395 m3/hr]. At 10000 tpd Flowrate = 2319 gpm [527 m3/hr]. The slurry S.G. can be determined from the same bulletin, using the S.G. of the solids (2.60) and 50% solids by wt. in the pipeline. The S.G. of the slurry is 1.44. 2. The appropriate pipeline size is determined with the following assumptions: Two equal sized lines are both running at all times with a third for backup. Alternate, one larger line is running at all times, and one line is for backup. The carrying velocity is about 8 feet per second [2.44 m/s] (assuming the solid particles will settle at approximately 7 ft. per sec. [2.13 m/s]). This will minimize pipeline sanding.

From the nomograph on page 9: The velocity (v) in the two 611 sch. 40 steel pipelines, at 1739/2 or (870) gpm is v = 9.8 ft./sec. [3.0 m/s]; at 2319/2 or (1160) gpm is v = 13 ft./sec. [4.0 m/s]; The velocity in the two 811 sch. 40 steel pipelines at the flowrate of 1739/2 or (870) gpm is v = 5.8 ft./sec. [1.8 m/s]; At 2319/2 or (1160) gpm is v = 7.6 ft./sec. [2.3 m/s]; Using only one 10 sch. 40 steel pipeline, the velocity at 1739 gpm is v=7.2 ft./sec. [2.2 m/s]; At 2319 gpm, v = 9.4 ft./sec. [2.9 m/s]. 3. Determine the equivalent length of pipe (Le) in order to calculate the friction head loss due to the flow velocity. The valves and fittings can be described as an equivalent length of the same size pipe. For example from the Crane Technical Paper #410 (page 10), a 90 degree long radius (90) elbow has an equivalent length expressed in length/diameter (L/D) = 20. This means multiplying the pipe diameter in feet x 20 yields the equivalent fitting length (Le). For each 6 (0. 5 ft.), 90 elbow, the Le = (0.5) (20) = 10 ft. [3.05 m]. For each 8 (0.667 ft) 90 elbow, the Le = (0.667) (20) = 13.33 ft [4.06 m]. For 10 (0.833 ft.) 90 elbow, the Le = (0.833) (20) = 16.7 or 17 ft. [5.18 m]. Since the Clarkson knife gate valve is full port, its effect on pipeline length can be neglected. The actual pipeline length is 160 ft. Add the equivalent fitting length to get the total equivalent line length (TEL). For the 6" line, TEL = 160 ft. + (2) 10 ft. = 180 ft. [54.86 m]. For the 8 line, TEL = 160 ft. + (2) 13.33 ft. = 187 ft. [57 m]. For the 10" line, TEL = 160 ft. + (2) 17 ft. = 194 ft. [59.13 m]. Using the friction Loss Nomograph, page 9, the friction loss (f) for each line size and at each flow volume can be


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determined. For standard steel pipe C = 1 00. With the 6" line (assuming 1/2 the total flow in each of 2 lines): At 870 gpm the loss is 9.2 ft./100 ft. of pipe (180 ft.), or f = 17 ft. [5.18 m]. At 1160 gpm the loss is 15.5 ft/100 ft. (180 ft.), or f = 28 ft. [8.53 m]. With the 8" line (again at 1/2 total flow): At 870 gpm the loss is 2.3 ft./100 ft. (187 ft.), or f = 4.3 ft. [1.31 m]. At 1160 gpm the loss is 4.0 ft./100 ft. (187 ft.), or f = 7.5 ft. [2.29 m]. With the 10" line (with, full flow in one line): At 1739 gpm the loss is 2.8 ft./100 ft. (194 ft), or f = 5.4 ft. [1.65 m]. At 2319 gpm the loss is 4.8 ft./100 ft. (194 ft.), or f = 9.3 ft. [2.83 m]. 4. Plot the elevation head (h) and the friction loss (f) curves, for each line size, on a linear graph of head vs. flow (Graph #2). Because the friction loss at the maximum flowrate condition of 1160 gpm is greater than the available static head, the 6" line cannot carry the maximum required flowrate (see detail A on Graph #2). Graph #3 (Page 10) is a replot of the same data eliminating the 6" line. This graph shows the friction that the CValve will need to add to the system at each flowrate to control the flow. This is the vertical distance (in ft.) at each required flowrate value, from the static elevation head line to the friction curve for each pipeline.

For the 8" line: The pressure drop at 870 gpm is 20.8 ft. or 9 psid [62 KPaD]. At 1160 gpm, the pressure drop is 18.1 ft. or 7.9 psid [54.5 KPaD]. For the 10" line: The pressure drop at 1739 gpm is 19.6 ft. or 8.5 psid [58.6 KPaD]. At 2319 gpm, the pressure drop is 15.5 ft. or 6.7 psid [46.2 KPaD]. 5. To calculate the valve Cv required, at each flow condition, use the equation: Cv In general, Cv (max) and, Cv (min) For the 8" line: Cv (max) Cv (min) = = 1160 870 (1.44/7 .9) = 495 (1.44/9.0) = 348 = Q (min) [S.G./ P(max.)] = Q (max) [S.G./ P(min.)] = (Q)(S.G./ P)

For the 10" line: Cv (max) Cv (min) = = 2319 1739 (1.44/6.7) = 1075 (1.44/8.5) = 716TVCRN-0207 Page 7



6. Since all the required information to select the pipeline size and the C-Valve size has been determined, the next step is to go to the Cv curves for each pipeline size and select the proper valve and port size. The following criteria should be considered: A. Choose a valve/port combination that does not approach either end of the Cv curve, i.e. mid-range on the curve. B. The velocity should be greater than 7 and less than 15 feet/sec. [greater than 2.1 and less than 4.6 m/s] if possible, to minimize pipeline sanding and wear. C. Initial cost favors using the smallest valve. D. One larger system may cost less than two smaller systems. E. For future expansion, it may be desirable to select a large valve. Based on all the above considerations, a reasonable selection would be the single 10" pipeline size and the 8" C-Valve with the 8 x 6 reduced port sleeve. This combination has a minimum Cv of 324 and a maximum Cv of 2450, which covers the required data range. If the flow requirements change, we can readily install either an 8 x 4 reduced port, or an 8 x 8 full port sleeve.

Note: This example is calculated on the basis of water, even though the actual media will be 50% solid slurry. The effect of slurry varies greatly depending on many variables such as: material properties, particle size distribution, temperature, viscosity, etc. The slurry will likely cause an increase in the effective static head, and also an increase in the friction head loss. Since both these values increase, we can sometimes neglect them. If a more precise calculation is required, the actual slurry should be tested in a scale model piping system to determine the actual rheological properties


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Clarkson C-Valve Sizing GuideNomograph for Friction Loss


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Clarkson C-Valve Sizing GuideRepresentative Equivalent Length in Pipe Diameters


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Clarkson C-Valve Sizing GuidePulp Determinations


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Clarkson C-Valve Sizing GuideSlurry Transport Using Centrifugal Pumps


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Clarkson C-Valve Sizing GuideTypical Slurry Pump Performance Curves


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Clarkson C-Valve Sizing GuideSizing Curves

The following pages contain the valve flow coefficient (Cv) curves for most practical combinations of pipe size and valve sizes. Where the valve body is smaller than the pipe size, the effect of reducer friction has been included in the Cv curve value. After the pipe size and the Cv range of the system have been determined, select the valve and sleeve combination that fits closest to the middle of the valve operating range. The flow characteristic of the C-Valve product line ranges between linear and modified linear. A linear characteristic can be obtained by the use of a reduced port sleeve. The reduced port sleeve develops a partial restriction to flow when in the wide-open position. Each incremental change in the valve position produces proportional change in flow, The full port sleeve produces a modified linear characteristic in which the first 10 to 40 percent of valve closure produces a small change in flow; then approaches, linear behavior upon further closure. The lag in flow control is greatest when the port size is equal to the pipe size and is desirable only when large turn

down ratios are required. The Cv curves represent the performance of each valve and sleeve combination up to the point of incipient cavitation. The valve is capable of intermittent operation in the cavitating condition and at differential pressures up to 50 psid [344 KPaD]. Continuous cavitation should be avoided as this leads to shorter sleeve life, higher pumping costs, and less accurate flow control. Ideally, the piping system should be designed so that the differential pressure across the valve is minimized, particularly in larger valves. This can be accomplished by applying the proper size pump to the system and avoiding very long pipe runs. Usually, more than one valve and sleeve combination will fit the sizing criteria above. The valve choice will then be based on cost, desired flow characteristic, anticipated system throughput changes, and accuracy of initial sizing data. A large valve will cost more than the next smaller size valve with equal flow capacity. The larger valve may offer more flexibility in flowrates, more desirable flow control, and longer sleeve life.


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Clarkson C-Valve Sizing GuideCv 1 Pipe Size


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Clarkson C-Valve Sizing GuideCv 1.5 Pipe Size


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Clarkson C-Valve Sizing GuideC-Valve Sizing Input Data

In order to properly size your C-Valve application, contact the factory for assistance. The sections below are provided as a guide and format to be used to collect to the required information for correct sizing for your application. Customer Information Your name Company Phone E-mail Address City Zip Code Description 90 deg EL 45 Deg EL Other EL Tee Reducers Valves Pipe Length Misc. Application Data Process Conditions Pipe & Fitting Schedule Size Qty Discharge Qty Suction

Fax

State Country

General

Body

Actuator/ Positioner Signal Conditioner Pump Data (1)

Tag No. Service Line Size, SCH. Function Body Size End Connection & Rating Body Material Sleeve Material Type of Actuator Air Supply - PSIG Input Range Action Type Dir. Rev. Input Signal Output Signal Manufacturer Model Speed (RPM) Suction Discharge Impeller Net Static Head

Accessories

Fluid/Slurry Units (GPM, TPD, M3/Hr) Qty. Min. Qty. Max. Qty. Normal @ F.T. Normal Inlet Pressure Maximum Inlet Pressure Delta P Normal Delta P Shutoff (2) Specific Gravity Mixture Specific Gravity Solids Normal Temp. Deg F Maximum Temp. Deg F % Solids Cv Normal Cv Maximum Filter Regulator Gauge Other

Notes: 1. Pump performance curves may be provided in lieu of these items. This blank space provided for piping diagram.

2. Depends on system and sleeve

www.tycovalves.comThe data presented in this bulletin is for general information only. Manufacturer is not responsible for acceptability of these products in relation to system requirements. Patents and Patents Pending in U.S. and foreign countries. All rights reserves. Printed in U.S.A. Tyco reserves the right to change product design and specifications without notice. Copyright 2001.


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C-Valve Sizing Guide