In-Line Pressure and Vacuum Relief Vent


In-Line Pressure / Vacuum Conservation Vent is used to conserve costly vapors and to protect a tank or vessel from damage caused by excessive pressure or vacuum accumulations during normal operation. This vent is particularly suited for mounting inside tank house installations. Outlet pipes can direct vapors to some appropriate area for discharge. Locating the vent inside the building facilitates maintenance and eliminates hazardous roof top inspections.


  • Certified flow curves validating flow characteristics of unit
  • Certified test report verifying specified settings and leakage performance
  • “Air-cushion” pallet design for low leakage performance of no more than 1 SCFH at 90% of the set pressure
  • Pallet assembly guides and center pallet stem guide to ensure proper alignment of pallet assembly on the seat and smooth lifting and reseating action
  • Automatic condensate drainage design to mitigate freezing, binding and clogging
  • Swing-bolt design facilitating inspection and easy maintenance
  • Serialized unit and associated weights for easy identification and traceability
  • Sizes: 2” (DN 50), 3” (DN 80) and 4” (DN 100)
  • Connections: Outlet connection has standard NPT threads. Inlet connection mates with 125# / 150# ANSI and DIN PN 16.
  • Materials: Aluminum, Ductile Iron and Stainless Steel
  • Standard Setting Range*: Pressure: 1 – 26 oz/in2 | 4.31- 112.04 mbar
  • Standard Setting Range*: Vacuum: 1 oz/in2 | 4.31 mbar

*Settings vary by size

  • Connections: Other drilling patterns available upon request.
  • Diaphragm Materials: FEP, Viton®, Buna N, EPDM, Neoprene; other materials available upon request
  • Material certifications for castings
  • Special Coatings: PROSHIELD™, FEP and Kynar®
  • Clamp-on “Steam-Jacketing”


Viton® is a Registered Trademark of E. I. DuPont de Nemours & Co., Inc.
Kynar® is a Registered Trademark of Arkema, Inc.