Pressure responsive valve

A drip preventing valve adapted for installation in a conduit (2,5) between a pump discharge outlet and a nozzle (3), comprising:

• a. a first pipe fitting (6,14) having an open end and an opposite end adapted for connection to said conduit;
• b. a second pipe fitting (10) extending within said open end of the first fitting and cooperating with said first fitting to define a chamber, said second fitting having an inner end with a valve port (10a) encircled by a valve seat (10b), and an outer end attachable to said conduit for fluid communication therewith;
• c. closed, flexible-walled, gas-filled cell means (11,15) within the chamber, said cell means being a single cell (11) formed of a section of flexible tubing flattened and sealed at its ends;
• and
• d. means in the chamber opposite the seat and limiting the movement of the cell means in a direction away from the seat, said cell means having an unstressed dimension in said direction greater than the distance between the seat and said movement limiting means, so that when the pressure within the cell means is at least equal to the pressure in the chamber, the cell means engages the seat and closes the valve port, said cell means being compressed when the pressure in the chamber is greater than the pressure in the cell means to decrease said dimension of the cell means and open the valve port.