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Pressure & Vacuum Relief Valves

Features & Benefits
  • Compact size – lightweight, easy to handle and install
  • Optimised design – high performance and flow capacity
  • Superior air-cushioned sealing – no measurable leakage below 90% of set pressures and <1SCFH at 90% of set pressure
  • Low leakage – meets requirements of API Std 2000 and EN ISO 23800
  • Cost effective – minimum product loss and maintenance
  • Superior quality – designed and tested in the UK
  • Versatile – wide range of design/venting options and pressure/vacuum settings
  • Flexibility – wide range of materials, sizes, alternative connection types and proximity switches available
  • Excellent service – pre and post-sales technical support
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Principles of Operation

Elmac Technologies’ Pressure & Vacuum Relief Valves (PVRV), also known as Breather Valves and Conservation Vents, have weight-loaded or spring-loaded pallets. Flow through the Pressure & Vacuum Relief Valve is controlled by the weight of the pallet or the spring force acting on the pallet to keep the device closed.

Once the pressure or vacuum in the tank reaches the pallet closing force, the pallet will start to lift off the seat and allow flow through the PVRV Valve.

Due to their air-cushioned sealing technology, Elmac Pressure & Vacuum Relief Valves prevent emission losses until very close to the set pressure and prevent air intake until very close to the set vacuum.

The geometry of the PVRV Valves has been developed in order to optimise overall performance in terms of high flow capacity, set pressure, sealing and re-sealing.

The modular nature of Elmac’s Pressure & Vacuum Relief Valves means they can be tailored to meet specific customer requirements: whether this is pressure or vacuum protection only; or with the addition of vapours and gases either piped away or vented to atmosphere.

A weatherhood protects the pressure vent port and a mesh screen is fitted to prevent intrusion of foreign matter into the safety valve.

Standards Compliance

Elmac’s products comply with all relevant industry standards including ATEX & ISO 16852 (Flame Arresters); API 2000/ISO 28300 & NFPA30 (Venting & Storage of Combustible Vapours & Liquids) and possible BLEVE (fire engulfment) incidents. In addition, Elmac is accredited to the following international standards: ISO 9001 (Total Quality Management), ISO 14001 (Environmental Management) and OHSAS 18001 (Occupational Health & Safety).

Enviromental Management Quality Management EX CE

Technical Specifications

Set Pressurembar(g)2~692~6969~103469~1034
Set Vacuummbar(g)-2~-43-43~-480-43~-480-2~-43
psi (g)-0.03 ~ -0.62-0.62 ~ -6.96-0.62 ~ -6.96-0.03 ~ -0.62
Nominal BoreLW*H
RV1, RV10S
W* indicates width, which is not marked in figures. M: Weight is approximate for Series RV1 Valves. Does not include pallet weights.
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