 | Hydraulic systems typically have operating pressures ranging from several hundred psig upwards to 2000 or 3000 psig. It can be important to measure small pressure drops that occur throughout the hydraulic flow loop. As hydraulic fluid flows through fittings, filters, control valves, etc, small pressure drops occur that cause energy losses. Testing prototype hydraulic systems can mean measuring these small pressure drops so that the efficiency of the system can be optimized. |
 | The key to measuring small pressure drops in a hydraulic system is to use a differential pressure transducer that is capable of withstanding high system pressures while measuring low differential pressures. The DP transducer is plumbed across a fitting, for example, so that the + port is on the upstream side and the – port is on the downstream side. As the hydraulic fluid flows through the fitting, the pressure drop, perhaps just a few psi, is measured by the transducer. The upstream pressure could be 3000 psig, for example, and the downstream pressure 2996 psig. The pressure drop of 4 psi across the fitting will be accurately measured by a transducer whose full scale is, say, 5 psid. The transducer can withstand the roughly 3000 psig system pressure while measuring the small differential pressure that results from fluid flowing through the fitting. This pressure drop can be correlated to pump flow rates to help evaluate total system efficiency. |