• HYDAC Combinationvalves
    several functions in one cartridge

  • HYDAC Combinationvalves
    several functions in one cartridge


Compact design as the goal

A design with minimum space requirements and a variety of functions are frequently sought in a number of applications, especially in the mobile sector. To meet this customer requirement for a compact design that also allows different functions, HYDAC has developed various combination valves.



Integration of functions in HYDAC valve technology – Our combination valves offer a compact design

With these new combination valves, HYDAC has succeeded in creating compact designs. The integration of multiple functions in a single valve has made it possible to save space and weight. HYDAC combination valves therefore fulfil very different functions:



WKDRM08140Y- A compact quick change function through the combination of 3 valves in a single cartridge

A quick change function generally consists of a separate 4/2 way valve to initiate cylinder movement, a pressure reducing valve to prevent damage to the mechanics in the case that the locking bolt locks in and a bypass non-return valve to securely release the locking bolt. 

Our combination valve, the WKDRM08140Y, combines these three valves in a single cartridge and, due to this, it has a clear advantage in terms of both cost and the space required for installation. When de-energized, the valve produces pressure that is regulated to extend or halt the locking bolt. The pressure level can be set mechanically on the valve. If the valve is energized, the entire system pressure is routed to the cylinder port on the opposite side and the locking bolt can be retracted with greater force. 

The oil flowing back from the cylinder is routed freely to the tank. Our combining of the functions in a single valve provides a securely locked bolt position when the valve is de-energized and it also provides for a mechanically adjustable locking pressure. In short, our combination valve provides optimal pressure conditions for tool change, e.g. in the case of telescopic handlers.

DB10PY - combination valve for compact pressure release

Numerous applications, such as those for pressure release or shutting down parts of a hydraulic circuit, require a combination of adjustable pressure relief valves and normally open (fail-safe) 2/2-way poppet valves as bypass.

Our combination valve DB10PY integrates these two functions in one cartridge and thus allows an exceedingly compact design along with numerous advantages such as lower space, weight and installation space requirements. The simple application of a supply voltage is sufficient for controlling this valve.

Thanks to the modular system of the HYDAC valve technology, the combination valve is available in different nominal sizes (from 8 to 16), for different ranges of volume flow (from 60 to 300 l/min) and in different design options:

  • With proportional control and independently adjustable maximum and minimum pressures - PDB...PY
  • With inverse characteristics and adjustable maximum pressure - PDB...PZ-31

 ➔ All the designs are also available as a pilot-operated pressure control function


PWK10121WS - combination valve for lifting / lowering functions

It is often difficult to lower plunger cylinders without a load at a desired speed since there is normally low pressure on the control valve. Today's solutions therefore need several valves ➔ high Δp


The direct-acting, proportional spool valve PWK10121WS combines a 2/2-way needle valve with a fixed maximum flow valve. The maximum volume flow is monitored by integrating a metering orifice and, when the maximum value is reached, is limited independently by means of the valve. Since the volume flows through only one valve, Δp for lowering is reduced, thus enabling plunger cylinders to also be lowered without a load at the desired speed. 

The integration of functions therefore allows the plunger cylinders to be lowered quickly and load-free without an additional flow valve or the use of a pressure compensator. The maximum flow rate can be adjusted individually here. The PWK10121WS also has a continuous Q-I curve since there is no change in the flow force between the flow valve and the proportional valve.


All in all, the combination valve PWK10121WS is an ideal valve for lowering plunger cylinders without a load.

DWM12121ZD - Circulation pressure compensator with integrated pressure limiting for a precise flow control

Circulation pressure compensators are generally used for load pressure compensation in flow control. Besides a pressure compensator, an additional pressure relief valve until was necessary until now. The direct-acting circulation pressure compensator DWM12121ZD in a slide design already features an integrated pressure limiting function and therefore has lower space, weight and cost requirements. 

The pressure compensator’s job is to maintain a set flow rate independently of any pressure fluctuations. As a control valve in combination with an integrated spring, it maintains the pressure drop across a measuring throttle at a uniform level. The pressure compensator is used in connection with a needle valve for a 3-way flow valve and is often used as a "load-sensing" valve for pressure-independent flow control.

The DWM12121ZD therefore offers excellent stability across the entire pressure and volume flow range and a high degree of functional reliability due to the integrated stroke limitation. It is available for various control pressure differentials and with various options, e.g. with hydrodynamic damping or internal, constant unloading of the load-sensing line.

The DWM12121ZD is available in several different designs:

  • With magnetically switchable pressure limiting - DWM12121ZMD
  • De-energised with high pressure and energised with low pressure - DWM12121ZMD(Z)


➔ All these designs are also available with proportional control



All in all, HYDAC combination valves offer:


  • an exceedingly compact solution
  • lower space, weight and installation space requirements
  • the use of a standard inline connection housing
  • a flexible adjustment based on specific customer needs
  • a variety of additional options for valve selection


  ➔ the correct combination valve for your applications !


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