The pilot valves main function is to operate larger valves from a remote location requiring less force.
Pilot valves control a reduced flow feed while sending it to another valve, that typically controls a high pressure/high flow feed. Furthermore pilot valves are useful because they allow a small and easily operated feed to control a much higher pressure/higher flow feed. Consequently enabling ease of use that would otherwise require a much larger force to operate. This is also useful when a solenoid is used to operate the high pressure/high flow valve. Finally the valve is made up of sections, each of which contains two 3-way pressure reducing signal ports. In addition up to 6 sections can be stacked into the same valve to give a total of 12 signal ports. The cast-iron valve housing and a hardened, precision-ground steel reducer-valve spool ensures a long service life with minimal internal leaks. Finally special low-friction seals give effective protection against external leakage as well.
Pilot Valves Essential Characteristics
- Small dimensions enable simple, compact installation.
- Robust, simple design gives great reliability and easy servicing.
- Low, well-adapted lever forces and short lever strokes give good operating comfort.
- Lever forces can be specified per control-pressure port to give function specific actuation resistance.
- Low hysteresis gives consistent machine-function response to valve actuation.
- Good metering properties enable gentle, proportional control.
- Very wide range of control-pressure characteristics enables control of machine functions to be application-optimized.
- Wide range of control devices and accessories gives great flexibility in system design.
- Valve can be installed in arm rests of operator’s seat and fitted with site-suited lever to give very ergonomic control station.
- Quality materials and great precision in manufacturing, assembly and testing assure a quality product with low internal leakage and long service life.
- Total compatibility with Parker directional valves gives predictable and harmonious system characteristics.
- The data given is applicable at an oil temperature of 50 ºC (122 °F) and viscosity of 30 mm2/s (cSt) using mineral base oil according to DIN 51524.
- Supply pressure (pump pressure)……….max. 100 bar (1450 psi)
- Recommended supply pressure……….15 bar (218 psi) higher than max. control pressure
- Control pressure………max. 75 bar (1090 psi).
- Breakaway pressure……….min. 1 bar (14.5 psi), max. 16 bar (232 psi)
- Return-line pressure……….max. 3 bar (44 psi)
- Control flow……….max. 15 LPM (4 US GPM)
- Hysteresis……….max. 0.5 bar (7.3 PSI)
- Best performance is obtained using mineral-base oil of high quality and cleanness in the hydraulic system.
HLP hydraulic fluids (DIN 51524), automatic-gearbox oil type A and API CD engine oils can be used. Synthetic, fire resistant and environmentally friendly fluids can also be used. Please contact Ryan Hydraulic Service for further information about hydraulic fluids.
- Viscosity, function range……….10-5000 mm2/s (cSt)
- Viscosity, working range……….10-380 mm2/s (cSt)
- Filtration should be arranged so that the Target Contamination Class 16/13 according to ISO 4406 is not exceeded.
- Min. ambient temperature……….–40ºC (-40°F)
- Max. ambient temperature……….+60ºC (140°F)
- Min. oil temperature……….–20ºC (-4°F)
- Max. oil temperature……….+70ºC (166 °F)
- Temperature change……….max. 100°C/s., max. 212°F/s
- From pump connection to tank connection with the spool in neutral position and a supply pressure of 40 bar (580 psi) max. cm3/min……….(1.22 in3)per control-pressure port