HMX4 Mercury filled flanged – HART – ATEX – SIL2 – PLd



  • The HMX4 series of Gefran, are pressure transmitters for use in High-temperature environments and specifically designed for melt pressure measurement and available only to be used in large-scale fixed installations or in large-scale stationary industrial tools, typically extruders, or for laboratory B2B equipment for R&D purposes according to the European Directive 2011/65/EU.
  • The HMX4 series of Gefran is flanged pressure transmitters with HART communication protocol for use in high-temperature environments with explosive atmosphere presence.
  • The main characteristic of this series is the capability to read the temperature of the media up to 400°C.
  • The constructive principle is based on the hydraulic transmission of the pressure.
  • The fluid-filled system assures temperature stability.
  • The physical measure is transformed into an electrical measure by means of strain-gauge technology.
  • The SIL2 and PL d approvals make the product suitable for use in the Functional Safety applications, particularly in the process plants for the production of polymers, where it is an essential requirement.


  • Pressure ranges from: 0-17 to 0-2000 bar/0-250 to 0-30000 psi
  • Thick film extensimetric measurement principle
  • Accuracy: < ±0.25% FS (H); < ±0.5% FS (M)
  • SIL2 and PL d approvals for Functional Safety
  • ATEX certification for potentially explosive atmospheres
  • Flanged version
  • Protection level: IP66 (6-pin connector)
  • 1/2-20UNF, M18x1.5 standard threads; other types available on request
  • Standard diaphragm is 15-5 PH stainless steel with GTP+ coating
  • 17-7 PH corrugated stainless steel diaphragm with GTP+ coating for ranges below 100 bar-1500 psi
  • Other diaphragm types available on request