Model 3700

Description:

The Model 3700 manhole and emergency pressure vents provide emergency pressure relief beyond that furnished by the normal pressure vent for atmospheric and low pressure tanks, as well as providing a convenient access for tank cleaning, inspection and repair. Emergency relief valves provide relief from excessive internal pressure which may be caused by an abnormal condition, such as ruptured internal heating coils or an external fire. The Model 3700 does not provide vacuum relief and therefore vacuum relief must be supplied by the normal operating vent. For vacuum relief see Valve Concepts Models 3100, 3200, 3300 and 3600 series vents.

Available Sizes

• 16" (DN400)
• 18" (DN450)
• 20" (DN500)
• 24" (DN600)

End Connections

Flanged

Features

• Easy Inspection & Maintenance:The Model 3700 vent is a rugged design andmade to last. It is light weight for easy handling, inspection and maintenance. The easy removal of the pallet assembly allows unobstructed access into the tank for inspection and repairs.
• Set Point Pressure:Ranges between 0.79 and 21.81 oz/in², depending on pallet material and line size.
• Air Cushion Pallet Design:Standard diaphragm material is FEP TFE. The FEP TFE diaphragm, the thickness of which is based on the vent size and the customer specified set point, forms around the seat to provide a tight seal due to the air cushion pallet design. Also available in FKM, EPDM and Buna-N.
• Low-Leak Design:All units are tested to Valve Concepts, Inc. high standard for low leakage and set point accuracy prior to shipment. A certified test certificate is included with each vent verifying the set point accuracy. Seat leakage meets or exceeds API Standard 2000.

Technique

The manhole/emergency vent pallet provides an effective vapor-tight seal when the tank is not under emergency conditions. If the tank outbreathing requirements exceeds the capability of the normal pressure relief vent, under emergency conditions, the pallet will raise to allow vapor to escape, preventing damage to the tank due to excess pressure. The manhole/emergency vent pallet is bottom guided so that when the excess pressure is relieved the pallet will reseat to again provide a vapor-tight seal.