The Shand & Jurs 94210 Emergency Vent and Manhole Cover is an economical solution to emergency venting requirements where intermediate pressure settings are required.
The design of Model 94210 employs a flexible diaphragm affording a tight seal between the pallet and the corrosion resistant seat below set pressure. This also assures low leakage. The diaphragm is intended for normal ambient temperature storage. Special diaphragms for tanks storing products other than oils and gasoline are available.
When set pressure is achieved, the pallet starts to lift. Flow efficiency rises rapidly to approximately 60% of a perfect orifice at 40% excess of the set pressure. At higher overpressure the flow efficiency approximates 75%.
For tank venting or examination, the entire hinged cover may be lifted open in a matter of seconds, offering clear passage through the unobstructed opening. Since no gasket replacement or unbolting is necessary, this vent eliminates the expensive manpower needed to put conventional emergency vents back in operation.
Pallet construction permits a wide variety of pressure settings. See specifications for various pressure settings of all vent sizes.
Standard design is available in 8″, 10″, 12″, 16″, 18″, 20″, 24″, 30″ and 36″ sizes. The Standard Mounting Flange is 150lb. ANSI Flat Face. The body has three lifting ears that are used to raise and position the unit. This helps to protect the internal diaphragm during installation. Lifting ears are not available on 8″, 10″ and 12″ sizes. The 20″ and 24″ vents can be provided with flat face flanges to fit API 650 Roof Manholes. Special construction types are also available.
Shand & Jurs “Expanda-Seal” option is available on all pressure pallet assemblies. This feature significantly reduces leakage. The ballooning effect of the Teflon diaphragm effectively seals the valve.