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Diaphragm Seal - High Accuracy Threaded Diaphragm Seals



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High Accuracy and High Displacement Threaded Diaphragm Seals are ideal for applications where high sensitivity or large fluid displacement is key to proper instrument performance. Designed with a diaphragm welded to the upper housing, the lower housing is detachable from the seal body allowing for easy cleanout of the process cavity without losing system fill. The High Accuracy Threaded Diaphragm Seal is most commonly mounted to Smart Transmitters (Gauge, Differential, and Absolute pressure), low pressure capsule gauges, mechanical DP gauges, and mechanical pressure switches.

  • Extra Large 4.1″ Diaphragm for Maximum Sensitivity
  • Wide Variety of Wetted Material Options
  • 100% Helium Leak Tested Diaphragm Welds
  • Easy Cleanout Design with Multiple Flush Port Options


Diaphragm 316/316L SS, Hast C-276, Tantalum, Monel A400, Nickel 201, or Others
Lower Housing 316/316L SS, Hast C-276, Monel A400, Alloy 20, Hast B, 304/304L SS, or Others
Gasket Klinger C-4401, PTFE Durlon 9600, Grafoil or Virgin PTFE
Upper Housing 316/316L SS, 304/304L SS, Monel A400, or Titanium
Process Temperature Limits PTFE Gasket: -110/400ºF Klinger Gasket: -110/500ºF Grafoil Gasket: -40/750ºF
Ambient Temperature Limits Determined by the pressure instrument.
Minimum Recommended Span 2.5” & 3.5” Gauges: 30” H2O 4”, 4.5”, & 6” Gauges: 30” H2O Transmitter (Gauge Pressure): 15” H2O Transmitter (Differential Pressure): 15” H2Od Differential Pressure Gauge (D40/42 Only): 100” H2Od
Weight 12 lbs. Note: weight is approximate.
Maximum Working Pressure at 100ºF:

W71 Bolts Grade 8: 1,500 psi

W71 Bolts 316SS: 750 psi

W7N Bolts Grade 8: 4,000 psi

W7N Bolts 316SS: 2,000 psi

Data Sheet

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Installation Instructions

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