Motor pump, pump unit, and method of balancing impeller of motor pump

Patent metadata

Field	Value
Publication number	US-2024167478-A1
Application number	US-202218282747-A
Country	US
Kind code	A1
Filing date	Jan 5, 2022
Priority date	Mar 24, 2021
Publication date	May 23, 2024
Grant date	—

Abstract

The present invention relates to a motor pump, a pump unit, and a method of balancing an impeller of the motor pump. The motor pump includes an impeller (1), a rotor (2), a stator (3), and a bearing (5). The rotor (2) and the bearing (5) are arranged in a suction side region (Ra) of the impeller (1).

First claim

1 . A motor pump, comprising:
an impeller; a rotor fixed to the impeller; a stator arranged radially outward of the rotor; and a bearing supporting the impeller, the bearing being arranged outside a flow path of the impeller, wherein the rotor and the bearing are arranged in a suction side region of the impeller.

2 . The motor pump according to claim 1 , wherein the motor pump comprises a return vane arranged on a back side of the impeller.

3 . The motor pump according to claim 1 , wherein the motor pump comprises a thrust load reduction structure provided on a back surface of the impeller.

4 . The motor pump according to claim 3 , wherein the thrust load reduction structure comprises a plurality of back vanes attached to the back surface of the impeller.

5 . The motor pump according to claim 3 , wherein the thrust load reduction structure is a plurality of notch structures extending toward a center side of the impeller.

6 . The motor pump according to claim 1 , wherein the bearing is a sliding bearing, the sliding bearing comprising:
a rotary side bearing body attached to the impeller; and a stationary side bearing body arranged on a suction side of the rotary side bearing body.

7 . The motor pump according to claim 1 , wherein at least one of the impeller and the bearing is constructed from a lightweight material.

8 . The motor pump according to claim 1 , wherein the impeller is a centrifugal impeller comprising a side plate with a suction portion formed in a central portion of the side plate, and the side plate is arranged opposite a main plate, and
wherein the side plate has an annular protrusion extending from an outer edge portion of the side plate toward the suction portion, and the rotor is fixed to the protrusion.

9 . The motor pump according to claim 1 , wherein the motor pump comprises a suction casing arranged on the suction side of the impeller, and
wherein the suction side region is a region between the suction casing and the impeller.

10 . A pump unit, comprising:
a plurality of motor pumps according to claim 1 , and an inverter configured to control an operation of each of the motor pumps.

11 . The pump unit according to claim 10 , wherein the motor pumps are arranged in series.

12 . The pump unit according to claim 10 , wherein the motor pumps are arranged in parallel.

13 . A method of balancing an impeller of a motor pump according to claim 1 , comprising:
a process of forming a through hole in a center of the impeller; a process of inserting a balancing jig into the through hole, and rotating the impeller together with the balancing jig; and a process of determining a center of gravity of the impeller while rotating the impeller to adjust the center of gravity.

14 . The method of balancing according to claim 13 , wherein the method of balancing comprises a process of pulling out the balancing jig and then inserting a center cap into the through hole.

15 . A method of balancing an impeller of a motor pump according to claim 1 , comprising:
a process of inserting a balancing jig into a rotary side bearing body attached to the impeller, and rotating the impeller together with the balancing jig; and a process of determining a center of gravity of the impeller while rotating the impeller to adjust the center of gravity.

16 . A method of balancing an impeller of a motor pump according to claim 1 , comprising:
a process of forming a plurality of weight insertion holes along a circumferential direction of the rotor; a process of determining a center of gravity of the impeller; and a process of inserting a weight into at least one of the weight insertion holes to adjust the center of gravity.

17 . A method of balancing an impeller of a motor pump according to claim 1 , comprising:
a process of determining a center of gravity of the impeller; and a process of removing excess weight that causes a shift in the center of gravity of the impeller.

18 . A pump unit, comprising:
a plurality of motor pumps; and a control device configured to operate the motor pumps at variable speeds, wherein each of the motor pumps comprises:
an impeller;
a rotor fixed to the impeller;
a stator arranged radially outward of the rotor; and
a bearing supporting the impeller, the bearing being arranged outside a flow path of the impeller,
wherein the rotor and the bearing are arranged in a suction side region of the impeller.

19 . The pump unit according to claim 18 , wherein the motor pumps are connected in series, and
wherein the control device configured to:
calculate a lower current limit value based on an assumed current value during a normal operation of the motor pump;
compare a measured current value during a current operation of the motor pump with the lower limit current value; and
determine that an abnormality has occurred in at least one of the motor pumps in a case in which the measured current value is lower than the lower limit current value.

20 . The pump unit according to claim 19 , wherein the measured current value corresponds to a starting current value at a time of starting the motor pump.

21 . The pump unit according to claim 19 , wherein the measured current value corresponds to an operating current value during a steady operation of the motor pump.

22 . The pump unit according to claim 21 , wherein the control device is configured to determine the assumed current value based on at least one of a rated current value and an allowable current value of the motor pump.

23 . The pump unit according to claim 21 , wherein the control device is configured to determine the assumed current value based on a flow rate on a discharge side of the motor pump.

24 . The pump unit according to claim 21 , wherein the control device is configured to determine the assumed current value based on a pressure on a discharge side of the motor pump.

25 . The pump unit according to claim 19 , wherein the lower current limit value is determined based on the number of motor pumps.

26 . The pump unit according to claim 18 , wherein the motor pumps are connected in parallel, and
wherein the control device is configured to shift a startup timing of each of the motor pumps.

27 . The pump unit according to claim 26 , wherein the control device is configured to start a motor pump adjacent to the started motor pump after starting one of the motor pumps.

28 . A pump unit, comprising:
a plurality of motor pumps according to claim 1 ; and a plurality of inverters configured to control an operation of the motor pumps, wherein each of the inverters is configured to control the operation of each of motor pumps.

29 . A motor pump, comprising:
an impeller; a rotor fixed to the impeller; a stator arranged radially outward of the rotor; and a bearing supporting the impeller, the bearing being arranged outside a flow path of the impeller, wherein the rotor and the bearing are arranged in a suction side region of the impeller, wherein the impeller is a centrifugal impeller comprising a side plate with a suction portion formed in a central portion of the side plate, and the side plate is arranged opposite a main plate, and wherein the side plate has an annular protrusion being arranged radially inward of an outer edge portion of the side plate, and the rotor is fi

Assignees

• Ebara Corp

Inventors

• Konishi Yasutaka
• Kawasaki Hiroyuki

Classifications

• F04D15/0088

  Testing machines · CPC title

• F04D13/0606

  Canned motor pumps · CPC title

• F04D13/0646

  the hollow pump or motor shaft being the conduit for the working fluid · CPC title

• F04D13/06 Primary

  the pump being electrically driven · CPC title

• F04D1/08

  the stages being situated concentrically · CPC title