Masoneilan 173 Series

The Masoneilan 173 Series are spring loaded, direct-operated, pressure relieving or back-pressure regulators designed for steam, gas and liquid service.  They are available in ½” through 2” (DN15 through DN50) body sizes. These regulators are designed for continuous, rugged industrial use to provide years of reliable service.

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General features:

  • Flow to close design
  • Available with ISA Face to face dimensions
  • From 5 to 9 different CV’s for each size to assure high accuracy in regulation
  • Metal or Sot Seat
  • Internal pressure sensing (external on request)
  • Wide range of actuators according to the requested regulation range
  • Elastomeric or metal diaphragms
  • Fully sealed construction available (suitable for dangerous medium; ATEX compliant)


General Data


Pressure Relieving / Back-Pressure


Steam, Gas, Liquids


½” to 2” (DN15-DN50)


Ratings & Connections :

Screwed : NPT ½” through 2” (CN15-DN50)

Flanged : ASME CL150-CL600

Material : Carbon Steel, Stainless Steel, Other Alloys


Plug Type : Disc

Seat : Integral

Material : Stainless Steel (std.), others on request

Capacity : Cv ratings from 0.031 up to 32

Diaphragm Materials 

Polychloroprene, EPDM, FKM, Stainless Steel