Absolute and Gauge Pressure

Absolute and Gauge Pressure

Absolute and gauge pressure measurement covers continuous transmitters and pressure switches that track liquids, gases, and steam in a wide range of services. Gauge measurement references atmospheric pressure, while absolute measurement references a sealed vacuum; choosing between them determines whether barometric variation is ignored or measured. Cerabar transmitters and Ceraphant switches span these duties and are also commonly applied for pressure-based level indication in hygienic food applications, with devices offered with hygienic approvals as well as SIL and explosion-protection options.

Endress+Hauser offerings in this category are built around sensor cells and isolation concepts that match the process. In a silicon-cell design, operating pressure deflects a process-isolating diaphragm; a fill fluid transfers the force to a resistance bridge, and the resulting voltage change is evaluated by the electronics. Diaphragm seals and alternative cell materials extend compatibility where direct exposure would compromise reliability or maintainability.

Pressure switches provide discrete action for interlocks and alarms. The switch opens or closes an electrical PNP contact at a defined set pressure, and a 4–20 mA output is also available for integration into analog control and diagnostics. On-device LEDs and a digital display support local function checks, while PC-based operation/visualization supports standardized configuration workflows.

Performance advantages come from fitting the sensing technology to the envelope. Silicon-cell devices target high process pressures (up to 700 bar) with small flush-mount process connections, overload resistance, and minimized thermal effects. Diaphragm-seal versions broaden material and connection choices and cover process temperatures from –70 to +400 °C, enabling high-temperature services and difficult media while maintaining measurement stability.

Typical applications include pump and compressor protection, filter/strainer monitoring, reactor and vessel pressure control, steam and utility distribution, and vacuum/pressure steps in batch operations. Devices in this category are available with hygienic approvals and with options for functional safety and hazardous areas, supporting consistent deployment across regulated and safety-relevant services.

George E. Booth Co., an exclusive authorized representative of sales and service for Endress+Hauser.