HydraForce Insider Blog

5 Things to Consider When Applying Proportional Valves

Posted by David Price on Tue, Jul 05, 2011 @ 12:07 PM

Here at HydraForce our Technical Services department typically receives multiple question daily regarding our Proportional Valves.  Common questions include, "What is the proper dither frequency for a particular proportional valve?' and "What coil should I use with this type of system?".  Following these five simple rules when applying  proportional valves  will prevent field failures, reduce valve instability, and ensure that your system performs as desired without having to reach out to a tech service representative.


 

1. Applying dither to a valve reduces actuator friction and reduces hysteresis.  A good rule of thumb is to use 70 -250 Hz dither frequency on all SP, ZL, and PV valves (flow and directional control valves), and 200-300 Hz dither frequency on TS Valves (proportional pressure control valves). Otherwise, at lower frequencies the actuator will follow the dither signal and the valve output will appear unstable.

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Tags: proportional valves, Directional Control Valves, pressure control valve, proportional flow control valve, proportional pressure control valve, Proportional Directional Control Valves

Cartridge Valves Combining Multiple Functions into a Single Cavity

Posted by David Price on Wed, Apr 20, 2011 @ 15:04 PM

A cartridge valve’s function is represented with an ISO standard hydraulic symbol that characterizes the function that the valve performs.  In our many product pages, you can find many unusual valves with very peculiar and complex hydraulic symbols that appear to contain an entire small hydraulic circuit.  In this post I will discuss the principle beyond combining cartridge valves and provide a few practical examples that may help you save money when you are designing a hydraulic circuit.

 

The idea to develop Multifunction Valves came from our engineers noticing that particular combinations of valves were used over and over again in standard hydraulic circuits.  For example, a 2-way, 2-position SP proportional valve is typically paired with a pressure compensator to provide pressure compensated flow control.  This particular example drove the development of the PV Proportional Flow Control family of valves, which include the flow control and pressure compensator inside the same cartridge.  There are many other multi-function options, including the SPCL, SVCL, SVRV, EPFR, FRRV, and others).

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Tags: cartridge valves, benefits of cartridge valves, Directional Control Valves, proportional flow control valve, hydraulic circuit, manifold design

Proper use of an Orifice in a Hydraulic Integrated Circuit

Posted by David Price on Wed, Mar 09, 2011 @ 12:03 PM

The proper performance of a hydraulic system is usually attributed to major components such as the motor, pump and valves. However, there is another unsung component that contributes equally to a system's overall performance: the orifice. In most traditional main hydraulic valves, orifices are built into the casting or dismounting components mold by the component’s constructors. In a cartridge valve manifold (otherwise known as a hydraulic integrated circuit), you start with a blank sheet of paper. Therefore, it is important to know where and when an orifice can change the performance of your system.

The orifice is one of the most versatile components that we can add in our hydraulic circuit. The orifice can be used to limit the amount of oil in one part of our system, to bleed a pressure line to tank, or to transform a nervous and aggressive circuit into an efficient and highly controlled one. Often times the orifice has to simultaneously manage a very small amount of oil, control a dynamic flow rate and dump a system’s compensator. In many applications -- especially for hydrostatic transmissions -- it is important to control the dynamic pressure of the system to avoid pressure spikes and pressure ripple.

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Tags: Load Sensing, pressure control valve, proportional flow control valve, combine pressure control valve and flow regulator, hydraulic integrated circuit, Orifices