Model 981.27

Diaphragm In-Line Seals

For Flange Connections, Flange Type

Selected documents
Sales contact

WIKA Instrumentation Taiwan Ltd.

+886 3 420 6052
+886 3 490 0080


  • For direct, permanent installation in pipelines
  • For flowing, pure and aggressive media 
  • Chemical process industry
  • Petrochemical industry

Special Features

  • Completely round, no corners and edges, European Patent No. 0629846
  • For direct installation between two flanges
  • Wide choice of special materials


Process connection
for flanges following EN 1092-1 / ASME B 16.5
DN 25, 40, 50, 80, 100 or 1", 2", 3", 4"
Nominal size: see drawing and tables (DN)
Sealing face, Form B1 or ASME RF 125 ... 250 AA

Pressure rating
PN 16/40 or Class 150/300

Pressure ranges
preferably mounted to pressure gauges NS 63, 100, 160 or pressure transmitters, Pressure ranges 0 ... 0.6 to 0 ... 40 bar

Body and material of wetted parts
Stainless steel (AISI 316L)

Measuring instrument connection
Pressure gauge or transmitter directly welded, process pressure transmitter with threaded adapter


Process connection

  • Larger nominal sizes
  • Other flange connections on request
  • Sealing faces per EN 1092-1, form B2 or per ASME B 16.5, RF 125 AA, 500 AA, RFSF; EN 1092-1 groove and tongue; projection and recess; ASME B 16.5 snap ring groove form RJF (limited for special materials, please request)
  • Flame arrester approved for Zone 0

Material of wetted parts

  • Staniless steel 1.4571, 1.4435, 1.4541, Monel, Hastelloy B3, C4, C22, C276, tantalum
  • PFA coating max. +260 °C
  • ECTFE (Halar®) coating max. +150 °C

Measuring instrument connection

  • Capillary, when ordering please specify: length of capillary
  • Cooling tower (for directly mounted gauge when fluid temperature > +140 °C)


  • Custom lengths between 1 and 15 m
  • Soft polyethylene or PTFE armour
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