Proportional Valve w/ Integral Piloting Saves Cost
Product Announcement from HydraForce, Inc.
New Patented Solenoid-Operated On/Off or Proportional Valves with Integral Piloting or Load-Signaling Capability can Reduce Manifold Space Claim.
Patented SVCL and SPCL series valves "U.S. Patent #7,921,880" from Hydraforce offer the unique capability of providing integral piloting and load-signaling in a single solenoid-operated on/off or proportional cartridge valve. The new SPCL16-30, SPCL16-32, and SPCL16-40 are rated to 40 gpm / 150 lpm, and were designed to help reduce manifold space claim, cost, and material.
This is an efficient, compact and cost effective solution for directional
control and load-holding applications. Patents were recently awarded for these
unique and innovative new valves, allowing us to offer the most effective
solution to our customer. The SVCL and SPCL products are now released in both
10-size and 16-size variations. While the 10-size valves use the common VC10-3 cavity profile with a modified pre-drill as shown in the catalog, the SPCL16-30. SPCL16-32, and SPCL16-40 use the VC16-3SPCL and VC16-4SPCL cavities.
Rated operating pressure for all SPCL and SVCL valves is
3625 psi / 250 bar while the load-holding port number 1 is capable of 5000 psi /350 bar maximum pressure and is qualified to 4:1 burst pressure per ANSI test specifications. The SVCL and SPCL valves use HydraForce D-Series and E-Series coils with various connector options. E-Series environmental coils are reated IP69K.
They have been extensively tested and approved under severe mobile machinery application conditions. Coil test and option details are available at: www.hydraforce.com/Electro/Electcon.htm
SVCL10-30 and SVCL10-32 valves are low leakage, on/off solenoid operated poppet valves with an integral load-sensing check valve. External load-sensing shuttle valves are eliminated, allowing for a smaller, lower-cost installation. In the de-energized position, the sensing port is isolated from the load, preventing load drift and enabling the load-sense signal to be externally vented to zero when the system is inactive.
SPCL10-30 and SPCL16-30 valves are electrically-proportional, low-leakage poppet valves with integral load-sensing check valve capability. The proportional poppet design allows for accurate electro-hydraulic system control for a wide range of load sensing applications.
SPCL10-32 and SPCL16-32 valves are electrically-proportional, low-leakage valves with an integral piloting port. The piloting feature can be used in counterbalance circuits providing both superior load-holding, as well as accurate flow regulation.
SPCL16-40 valves are electrically-proportional, low-leakage poppet valves with two integral load-sensing check valves. The proportional poppet design allows for accurate electro-hydraulic system control for a wide range of load sensing applications.
SVCL and SPCL Valve Performance
• System Operating Pressure: 3625 psi / 250 bar
• Holding Pressure: 5000 psi / 350 bar at Port 1
10-size valves: 15 gpm / 57 lpm
16-size valves: 40 gpm / 152 lpm
@ 175 psi / 12 bar differential for SVCL10-30 and SVCL10-32
@ 225 psi / 15.5 bar differential for SPCL10-30 and SPCL10-32
@ 300 psi / 20.7 bar differential for SPCL16-30 and SPCL16-40
Leakage: 5 dpm between ports 1 and 3, or ports 1 and 4 for the SPCL16-40
15 dpm at port 2, or ports 2 and 3 of the SPCL16-40
• Manual Overrides: J, Y, and
M options are available for SPCL10-30 and SPCL10-32
M option is available for SVCL10-30 and SVCL10-32
Cavity: VC10-3B for the SPCL10-30 and 32, and the SVCL10-30 and
VC160-3SPCL for the SPCL16-30 and SPCL16-32
VC160-4SPCL for the SPCL16-40
To See Application Examples, please visit: spcl.notlong.com
Low Leakage Directional Control Circuit
This circuit shows a low leakage directional control circuit with a multiple load sense configuration using the SPCL16-40 style valve. In this circuit we've eliminated the need for four separate load sense check valves and two separate load drop check valves. The SPCL16-40 provides proportional control of the inlet and outlet flow of the double acting cylinder. In both cases the highest load sense signal supplied through the highest pressure pilot line is used to provide compensated flow to either end of the cylinder while simultaneously preventing cylinder drift.
The bottom most load sense port (port 3) provides load pressure signal to the compensator. The use of a compensator allows each SPCL to provide a consistent amount of flow to each function independent of load induced pressure. Using this circuit configuration, a return side directional element is eliminated without loss of cylinder stability, and the return flow provides a load sense signal to the compensator, ensuring load stability. This circuit provides separate meter-in flow control which optimizes the pressure drop and controllability of any given function. This circuit can be further modified to provide meter-in flow control and meter-out pressure control.
Pump-Unloading Directional Control Circuit
The SVCLxx-30 or SPCLxx-30 can be used in load sensing circuits as a
directional control, and for signaling system demand to either a pump unloading
element or a load sensing pump compensator. The circuit drawing above shows a
pump-unloading directional control circuit where the SPCLxx-30 regulates input
flow to the cylinder, SPxx-20 valves regulate return flow to tank, and the EPFR
provides excess flow unloading. Flow not required by the cylinder is vented to
tank at load pressure (plus spring value) rather than relief valve pressure,
improving system efficiency and reducing heat.
The RV08-29 relief valve is used to set maximum system operating pressure. When the valve setting is reached, pilot flow is vented allowing the EPFR to bypass pump flow to tank. The small RV08-29 is used in place of a separate high-flow relief, allowing an economical and compact package configuration. The RV08-29 is designed to provide stable performance in low-flow pilot circuits.
The SPCL and the EPFR are both part of HydraForce's family of multi-function valves which integrate two functions into a single cavity. The EPFR integrates a venting flow regulator into the bypass compensator. The flow regulator brings the sense line to zero when there is no demand at the cylinder, accelerating the compensator response speed. The flow regulator is pressure-compensated so that the vent flow does not increase at higher pressures, assuring high overall efficiencies.
Single Acting Cylinder Application
In a single acting cylinder application, the SPCLxx-30 is used to control
flow for raising the cylinder. In addition it provides the load-sense signal to
the ECR valve for excess flow unloading. The SPxx-20 proportional solenoid valve
controls lowering flow, while the ECxx-34 provides load compensation.
The SPCLxx-30 as well as the SPxx-20 are poppet-style valves, preventing load drift when holding the cylinder under pressure. The ECxx-34 includes a poppet sealed pilot stage, also preventing load drift, while assuring that the lowering speed is accurately regulated independent of the weight supported by the cylinder.
The ECR is another HydraForce multi-function valve. The ECR acts as a bypass compensator, unloading flow not required by the cylinder, to the tank. The valve incorporates a built-in relief valve to set maximum system operating pressure, eliminating the need for an external valve and
additional cavity drilling.
Directional Bridge Circuit
This shows a directional bridge circuit configuration using the SPCLxx-32
style valve. In this version the check valve in the integral sensing line is
eliminated, allowing the load pressure to be used as a piloting
The SPCLxx-32 provides proportional control of the inlet flow to the motor. A pressure signal, supplied by the pilot line of the SPCL, is required in order to open the counterbalance valve thus allowing the motor function. Using this circuit configuration, a return side directional element is eliminated, without loss of motor control. Return flow from the motor passes directly to tank, eliminating back-pressure, minimizing circuit components, improving overall efficiency, and significantly reducing cost versus a conventional directional control system.
The addition of a check valve allows the higher of two pressure signals to be used as a load sensing pressure. In these applications, please note that sealed pilot operated check valves and pressure compensated pumps should not be used in conjunction because the result would effectively eliminate the system's pilot pressure bleed path. This causes pressure to build in the pilot lines, prevents the pilot operated check valves from closing, and gives the working lines an open path to tank. Additionally, when using pilot operated checks in a load sense configuration, the spring bias must be set higher than the load sense pressure to ensure proper operation of the valve.
Disclaimer: Nothing in this document constitutes an implied warranty of merchantability or of fitness for a particular purpose. The information contained in this document is provided for technical illustration purposes only and may not be used as a statement of suitability for use in any particular application. Each application is unique and prospective purchasers should conduct their own tests and studies to determine the fitness of HydraForce's products for their particular purposes and specific applications.