Model 14040 Welded Diaphragm Seal

About the Model 14040 Welded Diaphragm Seal. The Marsh Bellofram Model 14040 Welded Diaphragm Seal offers a special diaphragm-to-upper design that allows the upper housing to be removed with the instrument still in place, without losing liquid fill. The same interlocking feature as the 14000 is used in the model 14040 to ensure precise alignment of the upper to the lower housing. Units are available in threaded connections for pressures ranging from vacuum to 2500 psi. Fill/bleed port screw in the upper housing is standard with an optional flush connection also available. Marsh recommends the use of diaphragm seals such as the Model 14040 Welded Diaphragm Seal to extend instrumentation service life and reduce downtime and maintenance costs, by protecting instrumentation from corrosion, clogging, freezing, or pulsation damage. Units are filled and calibrated to gauges only.



  • Welded diaphragm-to-upper interlocking design
  • Fill/bleed port screw as standard
  • Filled and calibrated for gauges only


  • Pressure gauge requirements from vacuum to 2500 psi
  • Corrosive installations
  • Installations where removal of the diaphragm seal is a service requirement