Commercial Pressure Switches
Class 9013, Type F and Type G - Technical Overview
Operating Points (Settings)
Every pressure switch has two operating points; one on rising pressure and one of falling pressure. The operating point on rising pressure is referred to as the TRIP POINT or cut out for pumps and compressors and the operating point on falling pressure is referred to as the RESET POINT or cut in for pumps and compressors. These operating points are called the SETTINGS of the switch.
- TRIP POINT (rising pressure)
- RESET POINT (falling pressure)
The differential is the difference in pressure between the trip point (cut-out) and the reset point (cut-in). It can be adjustable or nonadjustable (fixed).
Example: Cut-in 30 psi
Cut-out 50 psi
Differential 20 psi (50-30 psi)
The range is the pressure limits within which the operating points (settings) can be adjusted. The range of the Class 9013 pressure switch is referenced to the operating point on rising pressure (trip point). The differential subtracts from the trip point setting. During the normal operating cycle, system pressure should never exceed the upper limit of the range when using a diaphragm actuated switch. This will greatly reduce the life of the diaphragm.
Maximum Allowable Pressure
Maximum allowable pressure is the pressure to which a switch can be subjected without causing a change in operating characteristics, shift in settings, or damage to the device. Pressure surges may occur in a system during the start up of a machine or from valve operation. Surges are not normally detrimental to the life of a switch if the surge is within the maximum allowable pressure rating of the switch. Diaphragm actuated switches should not be subjected to more than 10 surges per day. More frequent surges will greatly reduce the life of the diaphragm.