Automatic centrifugal pump primer

Claim 1

In an automatic primer for a centrifugal pump, the primer having a float chamber serially inserted between the pump and a source of vacuum pressure, the float chamber having an outlet port, the improved primer structure comprising, a float member, a valve actuated by the float member for preventing outward flow through the outlet port, an actuator rod connected at one end thereof to the valve, the opposite end of the rod being connected to the float member for moving the valve to a closed position in response to predetermined float displacement, a second float chamber communicating with the outlet port, a float valve means disposed in the second chamber, a second outlet port associated with the second chamber, the float valve means closing the second outlet port in response to the presence of liquid in the second chamber, the float valve means serving to prevent fluid flow to the source of vacuum pressure should the float-member-actuated valve fail, a check valve communicating with the second outlet port for preventing vacuum flow from the vacuum source in the event that the vacuum pressure of the source is exceeded by the vacuum pressure in the first mentioned float chamber, a vent hole formed in the first-mentioned float chamber, a flap valve normally sealing the hole, and actuator means connected to the float member for opening the flap valve when liquid enters the first-mentioned float chamber and elevates the float member, opening of the flap valve permitting inlet of air into the chamber thereby eliminating the vacuum therein and allowing any liquid buildup to return to the centrifugal pump and automatically restoring the float chambers to ready-prime condition, said actuator rod including spring means associated therewith to bias the valve connected thereto away from closed position thereby preventing the vacuum source from holding the float-member-actuated valve in closed position when liquid in the first float chamber is removed.