Backflow prevention devices
First Claim
1. In a backflow prevention device including at least one spring operated check valve communicatingly interconnected with an inlet pipe and an outlet pipe, said check valve controlling fluid flow from said inlet pipe to said outlet pipe and preventing backflow from said outlet pipe into said inlet pipe, the improvement comprising means affixed about the circumference of said spring for shielding said spring in said check valve from transverse flow disturbances caused by said fluid flow to reduce pressure loss in said valve at rated flow and to eliminate clatter of said spring resulting from collision of adjacent turns of said spring caused by fluid flow through the spring windings, said shielding means having a length greater than about 40% of the extended length of said spring when said valve is in its closed condition, and means for limiting the movement of said check valve such that said shielding means extends over less than about 90% of the extended length of said spring when said valve is in its fully opened condition.
1 Assignment
0 Petitions
Accused Products
Abstract
A backflow prevention device is disclosed which includes a spring operated check valve and a shielding member for protection of the spring from transverse fluid flow disturbances. The shielding member is preferably cylindrical in shape and surrounds the spring longitudinally about 40% to 90% of the extended spring length.
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Citations
11 Claims
- 1. In a backflow prevention device including at least one spring operated check valve communicatingly interconnected with an inlet pipe and an outlet pipe, said check valve controlling fluid flow from said inlet pipe to said outlet pipe and preventing backflow from said outlet pipe into said inlet pipe, the improvement comprising means affixed about the circumference of said spring for shielding said spring in said check valve from transverse flow disturbances caused by said fluid flow to reduce pressure loss in said valve at rated flow and to eliminate clatter of said spring resulting from collision of adjacent turns of said spring caused by fluid flow through the spring windings, said shielding means having a length greater than about 40% of the extended length of said spring when said valve is in its closed condition, and means for limiting the movement of said check valve such that said shielding means extends over less than about 90% of the extended length of said spring when said valve is in its fully opened condition.
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7. A check valve for a backflow prevention device comprising:
- a valve housing;
a spring operated poppet type valve assembly within said housing;
a means for shielding said spring from transverse flow disturbances caused by the flow of fluid through said valve, said shielding means having a length of at least about 40% of the extended length of said spring when said valve is in its closed condition, said shielding means guiding said fluid flow about said spring whereby pressure loss in said valve at rated flow is reduced and clatter of said spring caused by fluid flow is eliminated; and
a means for limiting the movement of said poppet type valve such that said shielding means extends over less than about 90% of the extended length of said spring when said valve is in its fully opened condition. - View Dependent Claims (8, 9, 10, 11)
- a valve housing;
Specification