The A20 Series (2 inch/51 mm dial) and the A25 Series (2-1/2 inch/64 mm dial) Swichgage instruments are diaphragm-actuated, pressure-indicating gages with built-in electrical switches for tripping alarms and/or shutdown devices.
Ranges are available from 0-30 psi (207 kPa) [2.0 bar] through 0-300 psi (2.1 MPa) [20 bar].
These rugged, instruments are face sealed from the environment by the unique combination of a polycarbonate case and lens, a polished stainless steel bezel and O-ring seals. Tese gages are sealed from the external environment. Accuracy and protection from moderate overpressure is assured by a unique, unitized diaphragm chamber. A built-in pulsation dampener helps eliminate pointer flutter and is removable for cleaning.
For series A25P, the gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts have self-cleaning motion to ensure electrical continuity.
Model A20PE has internal snap-acting SPDT switches for three wire control and can be wired to make or to break a circuit.
Gage-only models, without switches (Murphygage instrument) are also available.
A20/A25 Series applications include: engines/equipment in oil field for lube oil pressure, water pump pressure, hydraulic pressure, air pressure, etc.
A25P Series Swichgage
The gage pointer makes with an adjustable contact to complete a pilot duty circuit.
A20PE Swichgage
A20PE (was A20EO). Features internal snap-acting SPDT switches, instead of the single pole/pointer contacts. When the switch closes on falling pressure, it becomes set, as pressure rises the switch resets (refer to wiring diagram).
A20PG Murphygage instrument
Gage without contact(s)