Setting up your backpressure regulator so that it remains stable during all transient conditions such as pump swaps or filter change-outs is extremely important to the overall reliability of your pump or compressor. Today let’s discuss a method of getting a backpressure regulator “dialed-in”.
One thing to keep in mind in selecting a backpressure regulator is that in most cases it’s difficult to find a “One size fits all” solution. In most cases an off-the shelf unit will require some tuning to match it with your system dynamics.
If a backpressure regulator’s speed of response is too fast during a sudden demand change (e.g. turning ON the back-up pump) the regulator might open too much dropping the oil system pressure and causing system instability. In order to adjust the speed of response a restriction such as an orifice plate or needle valve can be placed in the sensing line. The restriction will slow or dampen the opening response speed; however, if the restriction becomes too narrow then the regulator’s response in the reverse or closing direction can become too slow. One way to avoid this delayed response is to install a check valve around the needle valve allowing for oil to evacuate from the actuator quickly in the reverse direction ensuring the proper closing speed. A flow control valve with integrated check valve can be obtained from various tubing valve suppliers.
For more information on oil system solutions check out Lubrication and Seal Oil Systems - Common Problems and Practical Solutions, a white paper presented at the 22nd Annual Turbomachinery Symposium
To see a backpressure regulator in action CLICK HERE and experience the Fisher MR98 with External Pressure Registration.