PRV Rim Vent

PRV Rim Vent

Maxwell PRV Rim Vent (Pressure Relieve)

The Maxwell PRV Rim Vents are installed on tanks equipped with a rim seal system that creates a vapor pocket, such as a mechanical shoe seal or double wiper seal system.

The rim vent is connected to the rim vapor space by a pipe and releases any excess pressure or vacuum that is present. The rim vapor space is bounded by the floating deck rim, the primary-seal shoe, the liquid surface, and the primary-seal fabric.

Rim vents usually consist of weighted pallets that rest on the gasketed surface.


Commonly the given rules are that for single deck internal floating roofs a Pressure Relieve or Pressure Vacuum Relieve valve might be needed, for double deck floating roofs and spider decks having a low sinking depth a Pressure Relive valve only will be sufficient.


Maxwell Rim Vent sizes are custom calculated to meet each individual tank within the requirements of both regulations and customer wishes.


The most commonly used Maxwell Rim Vents are:

• PRV Rim vent (Pressure Relieve Valve) from 2” up to 14”, with a recommended pressure setting of (+) 2,2-2,5 mbar