Dwyer Instruments has released the Series AT-A3000, an ATEX/IECEx-approved photohelic pressure switch/gauge.
“The flameproof-approved Series AT-A3000 ATEX/IECEx-approved photohelic pressure switch/gauge functions as versatile, highly repeatable pressure switch combined with a precise pressure gauge employing the time-proven Magnehelic gauge design,” says Dwyer.
The device measures and controls positive, negative or differential pressures of air and compatible gases. Two photo-transistor actuated, DPDT relays are included for low/high limit control.
Set-point indicators are controlled by knobs located on the gauge face (accessible opening case after de-energising instrument). Set-points can be interlocked to provide variable dead band which Dwyer says is ideal for control of fans, dampers, etc.
“Gauge reading is continuous and unaffected by switch operation, even during loss of electrical power,” says Dwyer. “Flameproof enclosures are available in aluminium with a glass window, which allows for viewing of set-point needles and process pressure.”