Pressure switches now certified for hazardous areas

A range of compact, low cost pressure switches are now available that are ATEX-certified for use in Zone 0, Zone 1 and Zone 2 gaseous atmospheres.

The new 901 range of ATEX-certified pressure switches, from Aldermaston-based sensor specialist Impress Sensors, are ideal for monitoring overpressure, vacuum or differential pressure of both liquid and gaseous substances, including aggressive media, in hazardous environments. The switches can be used to monitor fluid levels and filters, as well as excessive or inadequate pressure and pressure differentials in closed systems.

The explosion-proof pressure switches are ideal for a range of explosive atmosphere environments, including nuclear, oil and gas, chemicals, pharmaceuticals, sewerage and food processing.

The switches are available in a factory-set version, in which the pressure setting and switching differential are set by the manufacturer, or an adjustable version, the 901 Prescal, where the customer uses a scaled adjustment knob to alter the trip and reset pressure, without having to use a screwdriver.

A wide range of switch options are available, including pressure connections in various materials, shapes and sizes. Customers can also select from a diverse range of materials for seals and diaphragms. All switches are intrinsically safe and have been categorised as Temperature Class T4 and Explosion Group IIB or IIC.

Sam Drury, Sales Director at Impress Sensors & Systems comments: “Some of our customers need to monitor pressures in potentially explosive atmospheres. In the chemicals sector, for example, air mixtures and ignitable gases are commonplace and can cause explosions if a source of ignition is present. Therefore, industrial instrumentation devices such as pressure switches need to be protected accordingly. We are delighted to be able to offer these ATEX-certified sensors to the UK.”

The factory-set 901 switch can be set according to the customer’s specification at a fixed value between 5mbar and 12bar in the positive pressure range and between –5mbar and –900mbar in the negative pressure range. With the 901 Prescal switch, the switching pressure can be controlled using an adjustment knob. For process connections there is a choice of plastic or metal hose connectors or threaded connections, including BSP, NPT and metric standards.