Model 8700

Description:

The Model 8700 emergency pressure/vacuum vents provide emergency pressure and vacuum 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 vacuum relief allows the intake of air necessary to maintain the tank pressure within the permissible vacuum limit to avoid damage to the tank.

Available Sizes

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

End Connections

Flanged

Features

• Easy Inspection and Maintenance: The Model 8700 vent is a rugged design and made to last. It is light weight for easy handling, inspection and maintenance. The easy removal of the weather hood allows unobstructed access to the tank for tank entry, inspection and repairs.
• Maintains Accurate Settings: Minimum pressure setting for Aluminum to 1.5 oz/in². Minimum pressure setting for Carbon Steel and Stainless Steel to 2.39 oz/in². Maximum pressure setting for Aluminum to 1 psig. The minimum vacuum setting available is 0.2 oz/in² and the maximum vacuum setting is 4 oz/in².
• 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 and the seat leakage meets or exceeds API Standard 2000.

Technique

The 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 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.