SMALL-SIZED PUMP DEVICE AND ELECTRIC WATER HEATING POT

摘要

PROBLEM TO BE SOLVED: To make liquid be discharged efficiently, prevent cavitation, and make the liquid flow backward surely and smoothly. SOLUTION: A small pump device 1 is provided with an introducing part 10 for introducing liquid, a discharging part 11 for discharging the liquid introduced from the introducing part 10, and a liquid passage 12 for connecting the introducing part 10 to the discharging part 12. In the device, two sets of pumping mechanisms each consisting of a screw pump 13 having a lead screw 16 within a straight part of the liquid passage 12 and a centrifugal pump 14 having an impeller 17 are arranged on the same axis. The inside diameter in the straight part differs from place to place.