Flow sharing Pre/Post compensated valve...C M Y CM MY CY CMY K Flow sharing pre and post compensated valve Nowadays the constant evolution of mobile hydraulics towards energy saving

C M Y CM MY CY CMY K

Flow sharingPre/Post compensated valve


FUNCTIONAL ADVANTAGES OFFERED BYTHE EX FAMILY

PATENTED SYSTEM All the control valves belonging to the EX family work according to a principle designed by Hydrocontrol’s R&Ddepartment and covered by patents EP1860327 (A1) EP1860327 (B1) US2008282691 (A1) and US7581487 (B2). The valve LS signal is managedaccording to innovative procedures which are an absolute first in the flow sharing world, ensuring: • elimination of any LS signal bleed off, which canbe observed in most systems currently available commercially, and is often the cause of poor compensation accuracy, slow response and excessivesensitivity to operating conditions. • LS signal picking downstream from the local compensator: this will make signal detection ‘neater’’ improvingcontrol efficiency and accuracy. This Hydrocontrol patent has been widely tested on a variety of applications, with excellent results.

RESPONSE RATE The EX control valves’ strength resides in their quick, prompt response - achieved thanks to the functional advantagesbuilt into our patented system. Even the most critical applications such as excavator bucket shacking and the swift dynamics of forestry machinery– usually hard to achieve on flow sharing systems – can be successfully implemented by using EX family products. ACCURACY ANDSTABILITY The unique technical characteristics of the Hydrocontrol patent allow for outstanding flow control and compensation precision,not likely to be affected even by the most diverse operating conditions. Simultaneous functions are never mutually influenced, not even in the presenceof the same load factors (an aspect best highlighted in crawler machinery travelling). System stability itself is greatly benefited by the EX design; thesystem - also in combination with traditional overcenter valves - appears well balanced and able to effectively reduce oscillation and dynamic instability.

EFFICIENCY In addition to the well known advantages typically offered by flow sharing systems – which, associated with a variable pump,will dramatically reduce the machine operating consumption – the EX family introduces a number of interesting options, including pressure relief onthe LS signal to further increase energy saving and guarantee top efficiency levels. FLEXIBILITY The EX family control valves can be easilyadjusted to a variety of application fields, thanks to the wide range of available options and different types of available control systems.

COMPACT DIMENSIONS The carefully designed features and integrated electrohydraulic control ensure a highly compact, optimisedlayout. Integrated end plates are available in the final working section, adding to the system’s dimensional and functional efficiency.

PRIORITY The EX family allow to install side by side pre-compensated sections with post-compensated section. This feauture allow to establish a priority in the way the oil is directed and incresethe number of application where the EX family can be applied solving technical difficulties that beforerequired external components. Both Inlets and Outlets remain common for the pre and post compensatedsections making the assembling of the valve particularly convenient.


Flow sharing pre and post compensated valve

Nowadays the constant evolution of mobile hydraulics towards energy saving solutions finds the right answer in load-sensing technology. More workperformance, ease of use and controllability, improved safety and high energy efficiency are some of the winning features of these systems. The load-induced pressure downstream of an orifice is sensed from the pump and the flow is adjusted to maintain a constant pressure drop across the orificegetting a load independent flow. The orifice is typically a directional control valve with proportional flow characteristics. In hydraulic systems subjectto wide fluctuations in flow and pressure, load-sensing circuits can save substantial amounts of input power.

POST-COMPENSATED SYSTEMS


A special precompensated version has been developed, by applying the technology used for post-compensated EX versions. The characteristics of precompensated valves are well known in themarket, given the popularity of this technology. Starting from a common inlet section, it is possible toobtain both the anti-saturation (Flow sharing) EX version and a pre-compensated Load Sensing EXversion. Two versions can also be mixed together in the same valve in order to obtain priority circuits.

EX PRECOMPENSATED VALVES


A2 B2A1 B1

T1

SPECIAL FEATURES

LS Relief on Post-compensated section

Another feature not commonly found in flow sharing systems is thepossibility to have a Load Sense relief on the single sections.The purpouse to use a Load Sense relief instead of a standard shockrelief is to improve the efficiency loss and save energy in the system.When a standard shock relief is used, the full flow across the reliefwill be directed to tank, if the pressure system exceeds the one settedon the particular relief.By using a Load Sense relief we avoid this and only a very minimalpart of oil will be directed to tank in the same condition with greatadvantage for the all system. By saving oil from going to tank, moreoil will be available for simultaneous operation and this will improvethe efficiency and performance of the system.In the EX family we have the possibility to install a Load Sense reliefon a post compensated section.The pressure limitation generated by the local Load Sense reliefapplies to both section ports, A and B.When using a Load Sense relief in a post compensated section, fewthings need to be kept in mind as general rules and because of thiswe suggest you to contact our technical department for more informationabout the correct way to do this application.

LS Relief on Pre-compensated section

The purpouse to use a Load Sense relief instead of a standard shockrelief is to improve the efficiency loss and save energy in the system.When a standard shock relief is used, the full flow across the relief willbe directed to tank, if the pressure system exceeds the one setted onthe particular relief.By using a Load Sense relief we avoid this and only a very minimalpart of oil will be directed to tank in the same condition with greatadvantage for the all system. By saving oil from going to tank, moreoil will be available for simultaneous operation and this will improvethe efficiency and performance of the system.A typical case showcasing the advantages offered by this design isthe grab function in loading cranes, or any other feature requiring thatapplied pressure be maintained, without affecting the speed of othersimultaneous movements.The Load Sense relief can be easily installed as a retrofit too.


A1 B1 A2 B2

T1


SPECIAL FEATURES

Flow control device on thelocal compensator

The local compensator of a section can be equipped with a specialknob which can be operated to adjust the maximum flow delivered bythe section concerned.This device acts by limiting the working stroke of the local compensatorand is operated when a single section is actuated.

This feature is highly appreciated because it ensures a certain degreeof operating flexibility - especially for those machines which must beequipped with different accessories (tractors and farming applicationsin general being a typical example).

The flow control device can be easily installed as a retrofit kit, too.

Flow inhibiting device

The EX family offers a unique patented function to implement machinecontrol logics: in the presence of mechanical and hydraulic controls,too, it is possible to inhibit certain features, by preventing localcompensator opening.This feature is implemented via a special kit to be used on dedicatedbodies. The compensator opening pilot can be drained to the returnline via either a solenoid valve or a hydraulically piloted valve.Using a single piloting valve located on the end plate allows severalsections to be simultaneously inhibited.The control valve sections 2 and 3 shown in the diagram exclusivelywork in the presence of Pp piloting. Section 1, by contrast, is alwaysactive.


Parallel connection of severalvalves

Thanks to an interesting construction design, it is possible to obtainparallel connection of several control valves without that the flowsharing function efficiency and simultaneity of movement being affected.The circuit available either for fixed or variable pump, requires P, Tand LS signal connection according to the following diagram.

This solution is especially successful in the loading crane or forestrycrane industries for single pump circuits.

High pressure carry over function

The Carry Over function is yet another unique option offered by theEX family.In fixed pump circuits, two control valves connected in succession canbe used to ensure flow through both valves’ inlet compensators. Thisspecial design is obtained by using a special inlet cover on thefirst valve.

This circuit is ideally suitable for trailer-equipped machines,since the connection between the two control valves isachieved by simply using one pipe for P and one pipe forT (no additional LS signal connections are necessary).



STANDARD WORKING CONDITION

Operating temperature range

Kinematic viscosity range

Max contamination level

Recommended filtration level

-20°C / +80°C

10 ÷ 300 cSt

9 (NAS 1638) - 20/18/15 (ISO 4406:1999)

β10 > 75 (ISO 16889:2008)

All information and diagrams refer to a mineral base oil VG46 at 50°C temperature (32 cSt kinematicviscosity)

GENERAL SPECIFICATION

Load Sensing post compensated flow sharing valve:

� Open Center with inlet compensator(fixed displacement pump)

� Closed Center (variable displacement pump)

EX34

1 - 10

7

34

130

80

350

10

EX38

1 - 10

7

38

150

100

350

10

EX54

1 - 10

9

54

300

250

350

10

EX72

1 - 8

11

72

450

350

350

10

TYPE

Working section number

Spool stroke (mm)

Spool pitch (mm)

RATED FLOW

Pump flow rate (l/min)

A/B port flow rate (l/min)*

RATED PRESSURE

Working pressure inlet port P (bar)

BACK PRESSURE (max)

Max pressure outlet port T (bar)

EX46

1 - 10

8

46

220

180

350

10

(*) Compensator with 14 bar Δp


OPTION CHART

EX34

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EX38

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EX54

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EX72

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TYPE

LS Signal pressure relief valve

Pump pressure relief valve

LS Signal dump valve (electric 12/24 Vdc)

Pump dump valve (electric 12/24 Vdc)

SPOOLS TYPE

Single acting

Double acting

Float spool

SPOOL ACTUATION

Hydraulic actuation

Lever actuation

Without lever

Cloche control

Proportional electrohydraulic actuation 12-24 Vdc (*)

ON/OFF electrohydraulic actuation 12-24 Vdc (*)

CAN BUS interface actuation

SPOOL RETURN ACTION

Return spring

Mechanical detent kit

Hydraulic load limit

Pneumatic control

Spools displacement sensor (HLPS)

PORT RELIEF VALVE

Antishock valve

Anticavitation valve

Antishock and anticavitation valve

Plug

EX46

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(*) We recommend to keep the T line for the electrohydraulic cartridges separeted from the T line of the valve.


Flow Sharing valve for 130 l/min inlet flow rate:suitable for mini-excavators up to 5 t, truck-mounted cranes up to 10 tm, small and medium-sized agricoltural (harvesting) machinery andwork elevator lifting platforms.


challengeby hydrocontrolFlow sharing pre and post compensated valve


Flow Sharing valve for 150 l/min inlet flowrate: suitable for applications includingtruck-mounted cranes up to 25 tm, forestrycranes, tractors and mini-excavators upto 6 t.




46Flow Sharing valve for 220 l/min inlet flowrate. Common applications for thiscontrol valve are telehandlers, midi-excavators, medium and large sizedbackhoe loaders, forestry cranesand crane trucks.

0 40 80 120 160 200 240

280

210

140

70

0 25 50 75 100 125 150

200

150

100

50


STANDARDTHREADS

EX46 G 1

G 3/4

1” 5/16 - 12 UNF SAE 12

1” 1/16 - UNF SAE 12



Flow Sharing valve for 300 l/min inlet flowrate. The most common application for thiscontrol valve are excavators, wheeledloaders, rough terrain cranes, drillingmachines, mobile cranes, mining andoff-shore equipment.

300

60

120

180

240

300

50 100 150 200 250


STANDARDTHREAD

EX54

UN-UNF (ISO-725)(ISO 11926-1)

1” 5/8 12 UNF SAE 20

1” 5/8 12 UNF SAE 20

1” 5/16 12 UNF SAE 16


1”1/4MA - 1”1/4UNC

3/4” MA - 3/4 UNC


Flow Sharing valve for 450 l/min inlet flowrate. Suitable applications include drillingmachines, wheeled loaders, telescopingcranes, marine cranes, mining and off-shoreequipment.




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Flow sharing Pre/Post compensated valve...C M Y CM MY CY CMY K Flow sharing pre and post compensated valve Nowadays the constant evolution of mobile hydraulics towards energy saving