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Big Hermet Pressure Switches

Big Hermet pressure switches are robust field-mounted instruments. The pressure sensing assembly is identical to a conventional Static “O” Ring type. The main difference is that the switching element assembly is hermetically sealed in a steel capsule. Switching elements are SPDT or DPDT.

Basic Big Hermet pressure switches with standard wetted parts are normally suitable for air, oil, water and non-corrosive process applications in hazardous locations and hostile environments

Big Hermet Pressure Switches use the BA housing as a standard and are normally suitable for a variety of process applications in hazardous locations and hostile environments because the electrical switching elements are hermetically sealed in a steel capsule that is UL Listed, CSA Certified and SAA Approved. However, to be completely UL Listed/CSA Certified, the BL housing has to be used.

These switches utilize a Piston-Spring combination to determine the adjustable ranges. 

Configuration choices are available for:

  1. Housing - Either BA or BL
  2. Switching Element - for different AC/DC ratings and dead bands
  3. Diaphragm and O-Ring - for different process medium compatibilities
  4. Pressure port - for different process mediums and process connection sizes
  5. Accessories - For miscellaneous such as Certificates, Special Coatings, Additional Tests

Specific application requirements can normally be met by selecting optional components, such as switching elements, diaphragm systems and pressure ports.

Pressure range: from 20 in. wc vac. to 4000 psi in varying ranges and different configurations
Available O-Ring Material: 

  • Viton
  • Viton GLT
  • Kalrez*
  • Aflas
  • Buna-N
  • Neoprene EPR

Also available in a Fire-Safe/Welded Diaphragm System and TCP Teflon-Coated Polyimide Diaphragm.

For more information on the details and options available, please download Big Hermet Pressure Switches (Form CAT455)