Excess Flow Valves for Flange Mounting in Container Service A3500 Series and A4500 Series


Designed for mounting in flanged tank connections with internal threads in the bottom of a container. They may be used in filling, withdrawal or vapor equalizing application. They provide high flow capacity with low pressure drop to minimize pump inlet line cavitation.

If a riser pipe to the vapor space is used with these excess flow valves, the minimum inside diameter of the riser pipe must be at least two times the valve thread size in order not to restrict flow to the side inlet ports.

Flange mounted excess flow valves are readily accessible for servicing and completely enclosed and protected in event of fire. Because there is no direct connection between external piping and the valve, stresses imposed on piping will not affect the excess flow valve.


  • Precision machined.
  • Generous flow channels provide low pressure drop minimizing cavitation in pump suction lines.
  • Cotter pin prevents loss of spring retainer due to vibration in service.
  • Stainless steel spring provides consistent closing flow and long service life.

Materials A2137 Series

Body Cadmium Plated Steel
Seat Disc Cadmium Plated Steel
Stem Stainless Steel
Spring Stainless Steel
Guide Cadmium Plated Steel

Flanged Installation In Container

NOTE: The opening in the tank flange should be machined with a ¼”-45° chamfer at the outer edge. The thread should be tapped one or two turns large as checked by a plug gauge. This and the undersize thread on the valve should permit the valve to be installed so that its outer face is at least flush with the outer edge of the flange.

The valve is screwed into this opening by fitting a ¼” flat metal piece into the slot and turning until hand tight. A lubricant may be used, but a luting compound is not necessary since this joint does not have to be gas tight.

If any difficulty is experienced in “making up” the valve to fit flush, as indicated, the thread in the tank flange can be tapped.

Design and construction of tank and flange must be in accordance with the appropriate section of the ASME Pressure Vessel Code.