ATMOSPHERIC RELIEF VALVES


  atmospheric relief valves

ASVIN manufactures atmospheric relief valves, pressure safety valves and safety devices for oil and gas, petrochemical and chemical industries, pipelines, thermal and nuclear power plants, sugar refineries and pulp mills .ASVIN range of products is manufactured in accordance with ASME, API and ISO standards and therefore can meet most of worldwide customers requirements. They can be supplied with IBR or any other third party inspection also. Specifically ASVIN can design and manufacture special valves to meet special customer requirements. The company is committed to compliance with legislation and has an established environment and health and safety policy. An ongoing commitment to customer care is met through the process of continuous improvement and the further development of our systems and processes towards meeting ISO 9001:2000.

ASVIN Atmospheric Relief Valve

ASVIN make water sealed soft seated atmospheric relief valves are primarily designed to provide emergency service automatic protection for turbine and condenser equipment. This rugged valve for large flow and low pressure relief has been especially designed for trouble free operation, low maintenance and premium tightness performance.

Although ASVIN soft seated atmospheric relief valve was intended for steam condenser and turbine applications, it has been found suitable for various applications on gas and vapours, where its soft seat tightness performance and large flow capacity matched the service requirements.

Pressure Range and Settings of atmospheric relief valves

MBP water sealed soft seated atmospheric relief valves are dead weight loaded up to 0.7 psig (50 mbar) and spring loaded up to 15 psig (1 bar). Set pressure tolerance is ± 5 % of set pressure in all cases.

Body       Square angle type, flanged inlet/outlet, vertical inlet, horizontal outlet .

Sizes       6” to 36”. Larger sizes and special designs on application.

Flanges   Standard is ASME l50 lbs. Others standards are also available.

Waterseal

ASVIN atmospheric relief valves are provided with a water seal around the disc. This water seal is designed to prevent any hydrostatic head build-up on the valve disc. The water seal is provided with two threaded connections for water supply and overflow. It is recommended to supply the water seal with a constant stream of water to compensate for evaporation.

Gauge glass on valve to monitor water level 

Available on request.

Materials

Standard construction is cast carbon steel (SA 216 Gr WCB)/ Boiler Grade carbon steel. Other materials are available, such as stainless steel

Construction  Trim materials

To provide trouble free operation over long periods, the moving parts of the trim are stainless steel.

Seating surfaces

Lower seat is carbon steel with stainless steel overlay (SS 304). Disc seat is elastomer bonded. Various elastomer types are available : Fluorocarbon as a standard, silicone, nitrile, ethylene-propylene, neoprene if specified. The soft material is bonded in a groove machined onto the lower face of the disc by a high temperature: high pressure moulding process. The soft material adheres perfectly to the disc metal. Elastomer has been chosen for its hardness to provide long, tight and trouble free operation without soft surface damaging.

Disc lift

To avoid long simmer and disc vibration at low lift, the design of the disc is provided with an angle reaction hood to get significant lift even at low over pressure. This design also assures a mechanical protection of seating surface when handling the disc

Lifting lever

All ASVIN atmospheric relief valves are fitted with a lift lever. The design of the lifting device is such that the disc reseats automatically when the lifting force is released.

Operation

ASVIN soft seated atmospheric relief valves are bubble tight at full vacuum (- 80 mbar). All valves are tested before despatch. At set pressure, valves will lift gradually as the over pressure increases and the opening will be sudden due to the specially designed shape of the disc. Valves will reseat tightly below set pressure and remain tight in service. The valve disc should be lifted regularly (once every six months) using the lifting lever to check valve operation

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