HomeCompany ProfileHistoryProductsContact Us

Valves and Switches

    
0 – 700 Bar VPR
Pressure relief valves are used when the system pressure (force of the connected hydraulic cylinder) should not exceed a certain value.

These precision adjustable valves can be set to any pressure valve between 0 and 700 bar by means of a turning knob.

After achieving the set pressure value, the excess oil is guided back to the reservoir (pressureless).

Pressure relief valves are supplied with the necessary fittings and 0.5m return hose.
  
  
Pressure Switch
0 – 700 Bar VPS
This precision adjustable pressure switch can be set to any pressure value between 0 and 700 bar by means of a turning knob. When the set pressure value is reached, an electrical alternating contact is activated.
   
This signal can be used:
  • For automatic pressure limiting
  • To report a certain pressure value
  • As an automatic motor on/off switch with “pressure guard” power packs
   
As soon as the pressure has reached the set value, a micro-switch (alternating contact) is activated. Should the pressure drop, the micro-switch starts the pump again in order to rebuild the pressure.
  
  
Solenoid Directional Valves
700 Bar, Including Pressure Set Valve VEP
 
Application/Function
Solenoid operated valves are used to control the connected hydraulic cylinder by means of a pendant remote control or further electrical
controls like pressure switches or limit switches.
   
Control Principle
All solenoid valves have 3 positions:
   - advance – stop – retract -
   
In neutral position (stop) the valves switch to “pressureless circuit” so that the oil flow is guided back to the reservoir while the connected cylinder is safely held under pressure.

Normally solenoid valves are mounted directly onto power packs but can also be remote mounted by using hydraulic piping.
   
Design
  • Long life “direct controlled” ball seal valves with leak-free “load hold function” in neutral position. The solenoids guarantee a very quick reaction of the valves so that cylinders can be controlled millimeterwise. The valves are suitable for continuous operation (100% on/off duration).
   
Modular Design
The modular principle allows special valve configuations e.g. control of multiple cylinder systems or specific control sequences.
  
Pressure Adjustment
All solenoid valves are equipped with a precision adjustable pressure set valve which allows the system pressure (force of cylinder) to be limited to any value from 0 to 700 bar.
   
Pressure Gauge
A glycerine damped pressure gauge GGY – 631 is standard with solenoid valves. 0 – 1000 bar, Ø 63mm. These can be calibrated in tons if required.
   
Mounting Flange
The valve flanges are designed in a way that valves (with pressure connector) can easily be mounted onto Yale power packs.
  
  

Safety Check Valves
700 Bar - VSM
These safety-check valves are used for those applications where pressure drops (e.g. holding of a lifted load) must be avoided. Depending on the location in an hydraulic circuit these valves can have different functions. The model VS – 11 can be directly screwed into the oil port of a hydraulic cylinder and works at this location as a “hose break fuse”. The design of the VSM – 21 ensures that the pressure is held precisely and that pressure drops caused by operating the directional valve are avoided.
   
Operation
After closing the relief valve (hand wheel) the cylinder can be advanced via the by-pass. In direction to the cylinder the valves always have free flow. The built-in check valve ensures that a pressurised cylinder (e.g. a lifted load) is held precisely in stop position. A smooth lowering speed can be adjusted by opening the throttle valve (hand wheel) in order to relieve the pressure.

A safety pressure valve protects the cylinder from being overloaded by external loading.
   
Selection Advice
If the valve is to be screwed directly into a hydraulic cylinder, please order VSM – 11. If the valve is to be combined with the directional valve of a power pack please order VSM – 21.
  
  

Throttle- / Shut-Off Valves
700 Bar - VHM
These valves are used to shut-off hydraulic lines especially in multiple
cylinder systems. The needle valve VHM – 1 also allows you to throttle an
oil flow especially within lifting applications.
   
  

Directional Valves
700 Bar – Manually Operated
VHP - VHH
These directional valves control the oil flow in combination with hydraulic
power packs (YHH – 4/4 with hand pumps).

All valves have 3 lever positions to control movement of the connected hydraulic cylinder:
   
1. Left : cylinder advance
2. Middle : cylinder neutral (Pressureless circuit)
3. Right : cylinder retracts
   
In the middle position (hold) the piston of the cylinder stops and the oil flow is guided in a circuit back to the reservoir (“P” to “T”). The valves can be flanged directly onto power packs or remote connected by using hydraulic piping. “P” and “T” are connected to the bottom of the valve base.

In addition all valves are equipped with a second pressure oil port “P” at the back of the valve base. This port can easily be used to connect a pressure gauge and a pressure relief valve (e.g. VPR – 1).

The oil port “T” shall always be connected to the reservoir without any back pressure.
   
FULL SPECIFICATIONS AVAILABLE FROM :
CMCO Material Handling (Pty) Ltd

TEL: International: (+ 27 31) 700 4388 or in South Africa: (031) 700 4388
FAX: International: (+ 27 31) 700 4512 or in South Africa: (031) 700 4512

Postal Address: P O Box 15557, Westmead, 3608, South Africa

Or E-Mail us on: sales@cmcosa.co.za
   

 
Copyright by CMCO Material Handling (Pty) Ltd.