- How to Adjust a 2-Stage Pump
- Setting the Pump Compensator and System Relief Valve
- When and How to Adjust a Load-sensing Hydraulic Pump
- Cat 312, Adjusting Hydraulic Pump Pressure?
- increase pressure on electric hydraulic pump???
How to Adjust a 2-Stage PumpTwo-stage hydraulic pumps are used in hydraulic systems, and allow for the passage of a substance through the pump and to other devices installed in the system. You can adjust the various working aspects of the pump, including pressure settings and accuracy of the valve, by making minor adjustments with common household tools. Adjust the hydraulic gauge by locating the adjustment screw on the back of the gauge. Use a flathead screwdriver to turn the screw. Turning the screw allows you to adjust the screw needle, turning it to zero when needed. Adjust the pressure switch, located behind the hydraulic gauge, by using a wrench to loosen the lock-nut on the switch, then turning the adjusting screw. This switch can be adjusted to stop the pump when it reaches a given pressure setting. Turning the screw counterclockwise will decrease the pressure switch setting. Adjust the pressure regulating valve, located next to the pressure switch, by using a wrench to loosen the lock-nut on the switch, then turning the adjusting screw clockwise to increase the pressure setting. The switch should be adjusted to ensure a pressure differential of about psi. This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us. Step 1 Adjust the hydraulic gauge by locating the adjustment screw on the back of the gauge. Step 2 Adjust the pressure switch, located behind the hydraulic gauge, by using a wrench to loosen the lock-nut on the switch, then turning the adjusting screw. Items you will need Flathead screwdriver Wrench. About the Author This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.
Setting the Pump Compensator and System Relief Valve
Hydraulic relief valves limit the maximum system pressure to protect system components. The valves also limit the maximum output force of the hydraulic system. Although they have a number of variations, all valves work by balancing the hydraulic force with an adjustable spring force. Heat is created whenever the relief valve opens in response to a predetermined pressure. A correctly adjusted relief valve will enable the system to operate as designed while controlling the amount of heat generated. Refer to the machine drawings to determine which circuit requires adjustment. Locate the relief valve for the circuit. Relief valves are always piped in parallel to the pump and are normally as close to the pump as possible. Locate and remove the hydraulic hose or hoses on the system side of the relief valve. Cap off the hose and valve with the correct JIC caps or plugs as required. Do not cap off the return or tank side of the relief valve. Capping off or plugging unused hoses and fittings prevents the loss of hydraulic fluid and the introduction of contaminates into the system. Using any other method of capping or plugging a hose other than with the proper JIC plug or cap is unsafe and should never be attempted. This deadheads the hydraulic circuit in order to isolate the system to just the pump and relief valve. Connect a 5, psi pressure gauge between the relief valve and the pump. Most equipment will have a port already installed for this purpose. If no port is already installed, then use the correct adapter to install the gauge. Loosen the pressure relief valve adjustment all the way out. The relief valve will normally have a locking hex nut and either an Allen head adjuster or hand wheel adjuster. Start the equipment and activate the hydraulic circuit. The pressure reading on the gauge should be close to zero. Adjust the relief valve by turning the adjuster clockwise until the reading on the gauge builds to the pressure indicated on the machine drawings. This is what is known as the valve "cracking" pressure, which is the pressure at which the relief valve starts to open. Tighten the adjuster lock nut securely, being careful not to disturb the valve setting. Shut down the machinery and allow the pressure to bleed off. Remove the JIC plugs and caps, and reconnect any hoses that were removed in Step 2. Start the machinery, and test the relief valve by actuating the circuit.
When and How to Adjust a Load-sensing Hydraulic Pump
In order for the hydraulic system to run as efficiently as possible, two critical settings are the pump compensator and the system relief valve. Of all of the adjustments that we find made incorrectly, these two are the most common. Often the pressure setting of the pump compensator has been increased, sometimes above the setting of the relief valve. When this happens, the system will overheat badly. We have sometimes even seen heat exchangers added to a system for no other reason than because, at some point, someone turned the compensator above the relief valve. In order to set them properly, they must be set together. The first step is to determine the best pressure at which to set the valves. If we are fortunate, we have designer specifications available. Whenever we do have designer specifications and no modifications have been made to the machine that would change the requirements, we should adhere to the specs. Otherwise we must determine the pressure required to move the heaviest load the machine will ever be required to move. We do this by placing the machine under its greatest load and increasing the pressure until the load moves. When doing this, we must open any system flow controls and isolate any accumulators. Flow controls and accumulators can add resistance to the machine which will affect pressure readings. This is to ensure that the relief valve is set above its cracking pressure to avoid dumping across it, wasting energy and generating heat while moving heavy loads. With the system shut down, isolate the power supply so that the only flow path for fluid from the pump is through the system relief valve. Most well-designed systems have a manual hand valve immediately downstream of the power supply for just this purpose. Turn the relief valve adjustment counterclockwise to a very low setting. Do not turn it past the point where you no longer feel spring tension — many of them will back all of the way out! Turn the compensator fully clockwise. This will make the pump behave as a fixed displacement pump, delivering maximum flow at all times so that the pump will not de-stroke while you are setting the relief valve. Power up the system and you should have oil dumping across the relief valve at a very low pressure. For this example, increase the relief valve setting to PSI. Once the relief valve is set, reduce the compensator setting to PSI and your pressures are set. On a very few machines, the — PSI spread between the relief valve and the compensator settings will not be enough to overcome the cracking pressure of the relief valve. If, once the settings are made you find that the relief valve is getting hot, the relief valve setting must be increased until fluid no longer dumps across it. The most effective way to do this is to install a flow meter in the relief valve tank line and increase the setting until the flow meter reads 0 GPM. If you have no flow meter or if the relief valve tank line is not exposed, a laser temperature gun or an infrared camera can be used to determine if the relief valve is dumping. Call Us Today gpm gpmhydraulic. Search for:. Why do I Need One?
Cat 312, Adjusting Hydraulic Pump Pressure?