SELF-PRIMING PUMP

PROBLEM TO BE SOLVED: To provide a self-priming pump capable of eliminating necessity for increasing mold size of a casing cover above predetermined size even when requiring screw type sewage, drainage, and priming joints. SOLUTION: This self-priming pump is provided with an electric motor 1, a casing 3 provided with an impeller 6 fixed to a rotary shaft 2 of the electric motor 1, an impeller chamber for storing the impeller 6, a discharge passage through which water flowing out from the impeller chamber passes, and a feeding-out tank part for receiving flowing out water, a gas water separation chamber communicating with the feeding-out tank part, a water tank part for storing priming water to feed a part of water flowing out into the impeller chamber, and the casing cover 4 arranging the priming joint 14 for letting priming water flow in on a side face. The drainage joint 13 arranged to drain water remaining in a pump chamber when the pump is not used is provided in the casing 3. COPYRIGHT: (C)2006,JPO&NCIPI