400-401 All-Welded Diaphragm Seals from Ashcroft

400-401 All-Welded Diaphragm Seals from Ashcroft
The Ashcroft® 400 and 401 all-welded diaphragm seals protect pressure measuring instruments. Used to ensure process compatibility, they are also applied when process media exhibit high temperature, pulsation or the potential to clog an instrument connection. An ideal selection for applications requiring minimal potential leak paths.


400-401 All-Welded Diaphragm Seals Features:

  • Select diaphragm and lower housing materials
  • All-welded construction
  • Carbon steel rings (standard); 300 stainless steel rings (optional)
  • Pressure rated up to 4,400 psi; optional high-pressure rings to 9,000 psi (type 401: 5,000 psi )
  • Flush port (type 401) provides easy cleaning / flushing for process media prone to clogging



400-401 All-Welded Diaphragm Seals Applications:

  • Process Market:
    • Oil and Gas
    • Chemical and Petrochemical
    • Refineries
    • Water and Wastewater
  • Process Applications:
    • Oil and Gas Fracking
    • NACE Compliant Processes (Sour Gas Separation)
    • Biogas and Biodiesel



400-401 All-Welded Diaphragm Seals Specifications:

Process Connection Size
  • 1/4 to 1 NPT Male
  • 1⁄4 to 1 1⁄2 NPT Female
Instrument Connection¼ or ½ NPT Female
Pressure RatingUp to 4,400 psi, 9,000 psi (OPT.)
Added Tolerance±0.5% typical
Connection Style
  • 400: Threaded
  • 401: Threaded with flushing port


Download Ashcroft 400-401 All-Welded Diaphragm Seals Datasheet


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