Dry hydrant check valve

An above-ground dry hydrant, comprising:

• (a) an unpressurized hydrant pipe having a submerged end located within a body of water and an unsubmerged end located elevationally above a surface of said body of water;
• and
• (b) a valve mounted to the pipe which is operable to (1) open and permit a flow of water therethrough from said body in response to a demand negative pressure applied to the pipe at said unsubmerged end, and (2) impede a reverse flow of water therethrough in a direction extending towards said body to thereby enable said pipe to be filled with water;
• wherein said valve is a check valve wherein said check valve assembly includes:
• (i) a valve support plate formed with plural openings to permit fluid flow therethrough from said body of water;
• and
• (ii) a valve seal mounted to said valve support plate on a side thereof facing toward said submerged end, said valve seal being arranged to (1) at least substantially entirely cover said plural openings under the action of said reverse flow of fluid entering said pipe from said unsubmerged end, and (2) be deflected into and open position to permit flow of water through said openings from said body;
• said dry hydrant further comprising a vent valve mounted to said pipe adjacent said unsubmerged end thereof and which is opened to vent air within said pipe as the air is displaced by said reverse flow when said pipe is being filled, wherein said vent valve is connected to coupling adapter having one end attached to said submerged end of said pipe and an opposite end to which a hose is attached to selectively pump said reverse flow of water into said pipe or to apply said demand pressure thereto.

An above-ground dry hydrant, comprising:

• (a) an unpressurized hydrant pipe having a submerged end located within a body of water and an unsubmerged end located elevationally above a surface of said body of water;
• and
• (b) a valve mounted to the pipe and which is operable to (1) open and permit a flow of water therethrough from said body in response to a demand negative pressure applied to the pipe at said unsubmerged end, and (2) impede a reverse flow of water therethrough in a direction extending towards said body to thereby enable said pipe to be filled with water;
• said dry hydrant further comprising a vent valve mounted to said pipe adjacent said unsubmerged end thereof and which is opened to vent air within said pipe as the air is displaced by said reverse flow when said pipe is being filled.

An above-ground dry hydrant, comprising:

• (a) an unpressurized hydrant pipe having a submerged end located within a body of water and an unsubmerged end located elevationally above a surface of said body of water;
• and
• (b) a valve mounted to the pipe and which is operable to (1) open and permit a flow of water therethrough from said body in response to a demand negative pressure applied to the pipe at said unsubmerged end, and (2) impede a reverse flow of water therethrough in a direction extending towards said body to thereby enable said pipe to be filled with water;
• wherein said valve is a check valve;
• said dry hydrant further comprising an underwater strainer installed at said submerged end, wherein said check valve is located within said submerged end adjacent said strainer, said dry hydrant further comprising a bypass valve arrangement including a bypass passage having opposite ends respectively connected to said pipe on opposite sides of said check valve which is main check valve, one said end of said bypass passage being in communication with said strainer, and a bypass check valve mounted within said bypass passage and which is operable to open, under a predetermined reverse flow pressure, to permit back-flushing of said strainer while said main check valve remains closed.

A method of using an above-ground dry hydrant having an unpressurized hydrant pipe having a submerged end located within a body of water having a surface level and an unsubmerged end located elevationally above said body of water, comprising the step of:

• (a) filling said pipe with fluid to displace air therewithin;
• (b) preventing said fluid from entering said body through said submerged end by placement of a check valve within said hydrant pipe;
• (c) applying a demand pressure to the pipe proximate said unsubmerged end thereof to begin drawing water through said pipe from said body;
• (d) removing said demand pressure when drawing of the water is completely finished;
• and
• (e) draining the fluid in said pipe to approximately the same elevation as said surface level of said body of water.

A method of using an above-ground dry hydrant having an unpressurized hydrant pipe having a submerged end located within a body of water and an unsubmerged end located elevationally above said body of water, comprising the steps of:

• (a) filling said pipe with fluid to displace air therewithin;
• and
• (b) applying a demand pressure to the pipe proximate said unsubmerged end thereof to begin drawing water through said pipe from said body;
• and
• comprising the further step of periodically back-flushing a strainer connected to said submerged end, wherein a check valve is disposed in said submerged end upstream and adjacent said strainer to prevent filling fluid from entering said body of water during filling, and wherein said back-flushing occurs by directing the reverse flow of fluid around said check valve through a bypass passage and opening a bypass check valve in said bypass passage with a sufficient reverse flow back-flushing pressure which is greater than a predetermined pressure.