HMI Back Pressure Check Valves protect the contents of a pressure tank. These back pressure check valves should be installed as near to the tank as possible to achieve the greatest protection. The back pressure check valve is normally closed but will open when flow into the tank overcomes the valves spring. In this event, the valve will remain open so long as the flow is not stopped or the direction of flow is reversed. If the line flowing into the tank ruptures, then the back pressure check valve closes preventing the tanks contents from being released.

If the flow is in both directions, into and out of the vessel, the HMI Excess Flow Check Valve should be used. HMI Back Pressure Check Valves can also be used in other piping systems to limit the flow to one direction.

HMI Back Pressure Check Valves flow only a negligible amount under what the properly sized flow line will allow. To keep your cost down, exact flows are generally not determined or stated for these valves. However, if the exact flow and cracking pressure is required, we can supply a valve meeting your individual requirements.

Installation & Testing:

Although HMI Back Pressure Check Valves are designed and manufactured for trouble free service, HMI recommends that these valves be installed by qualified personnel and that periodic inspections be carried out to insure the valve is in proper operating condition. The frequency of these inspections should be determined by the customers preventive maintenance schedule. HMI recommends inspections of all safety valves at intervals not exceeding one year.

Cautions & Warnings:

Improper installation could cause serious damage to equipment and in some cases could cause serious injury or death, i.e., valve being installed with the flow in the wrong direction.

Back