| Applications Mechanical pressure switches, also known as hydro-electric pressure monitors, are used to connect or disconnect electric circuits. A pressure switch can serve as a control unit and as an optical or acoustic monitor or indicator. Barksdale pressure switches are chiefly used in hydraulic systems for monitoring minimum pressures, such as protecting pumps from dry operation or as protection for oil lubrication systems. They can also be used for monitoring maximum pressures, such as automatic switch-off or warning device before a pressure relief valve reaches its limit pressure (fig. 1). Another application for Barksdale pressure switches is the control of storage loading processes. After the storage capacity is reached (Pmax) the flow is stopped and the pump shuts down. When the storage pressure drops below a defined minimum value (Pmin), the pump is automatically started again. The switch hysteresis (Pmax - Pmin) can be freely selected with two pressure switches and one solenoid valve manufacturer (fig. 2). Within certain pressure ranges the storage process can be controlled with only one pressure switcr^ the KD1 compact pressure switch which Barksdale specifically designed for this application. The pressure set points Pmax and Pmin are factory set according to your requirements. Life Span and Accuracy The life span and accuracy of pressure switches depend on the frequency and peaks of pressure changes, the number of load cycles and temperature inf|uences Highest accuracy is achieved above 70 %s the longest life span below 30 % of the performance range ^ 3^ The best combination of life span and accuracy is, however, between 30% and 70% of the performance range. Contact Materials Barksdale pressure switches have silver contact microswitche^ On request we also supply microswitches with gold-plated contacts Gold-plated are almost exclusively used on microswitches that are only exposed to low electrical loads. Fig. 4 depicts the standard values for the use of silver or gold-plated contacts. We would gladly assist you in the selection of the material best suited for your application. Summary: The product of current and voltage should not exceed 0^2 VA. Recommended values: current should range at < 400 mA and voltage at < 30 V If operated on alternating current the above values are peak values. Contact Protection The micno switches (MS) used in the pressure switches are normally suitable for both direct and alternating current operation. Inductive, capacitive and lamp loads may, however, considerably reduce the life span of a micro switch and, under extreme circumstances, even damage the contacts. |