Ashcroft 740-741 High-Displacement Diaphragm Seals

The Ashcroft® 740 and 741 high-displacement diaphragm seals or isolation devices are used with low-ranged instruments or high static pressure dp gauges with low differential pressure. Used to ensure material compatibility, they are also applied when process media exhibits high temperature, pulsation or the potential to clog an instrument connection. An ideal product for satisfying low pressure measurement needs.

Key Features:

  • Wide selection of diaphragm and lower housing materials
  • Enlarged welded diaphragm; high displacement allows high sensitivity to
    pressure fluctuations
  • Flush port (type 741) provides easy cleaning / flushing due to process
    media prone to clogging


  • Style:
    Type 740: threaded
    Type 741: threaded with flushing port
  • Low pressure range capability; 30" IWC to 750 psi
  • Process size: 1/4" to 1" NPT female
  • Rated up to 750 psi

The 740 and 741 high-displacement diaphragm seals are ideal where low volume measurement and process protection are essential:

Process Market:

  • Oil and Gas
  • Refineries
  • Chemical and Petrochemical
  • Water and Wastewater

Process Applications:

  • Oil and Gas Fracking
  • NACE Compliant Processes (Sour Gas Separation)
  • Biogas and Biodiesel

Please Contact Us for more detail