# US 5,704,768 A · Motor pump family of centrifugal pumps

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,704,768 A
- Document ID: US5704768A
- Status: Granted
- Kind: A
- Application number: 08/713,958
- Filed: 1996-09-12
- Granted: 1998-01-06
- Earliest claimed: 1993-10-13
- Assignees: Ebara Corporation
- Inventors: Makoto Kobayashi; Masakazu Yamamoto; Yoshio Miyake
- Web page: https://patentgrep.com/patent/US5704768A

## CPC

- F04D 1/00: Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps (adapted for pumping specific fluids F04D7/00; priming or boosting F04D9/00)
- F04D 13/14: the pumps being all of centrifugal type {(deviation valves F04D15/0016)}
- F04D 1/06: Multi-stage pumps (F04D1/02, F04D13/10 take precedence)
- F04D 15/0072: {Installation or systems with two or more pumps, wherein the flow path through the stages can be changed, e.g. series-parallel}
- F04D 29/4266: {made of sheet metal}
- F04D 29/628: {especially adapted for liquid pumps}
- F05B 2230/601: using limited numbers of standard modules which can be adapted by machining
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G

## Abstract

A motor pump group has a plurality of centrifugal pumps of the same nominal port diameter including a plurality of impellers having stepwise greater outside diameters for stepwise higher pump heads, and a plurality of respective motors for actuating the pumps. The pump heads are classified into a low head section and a high head section. The low head section is handled by a single-stage impeller, and the high head section is handled by multi-stage impellers. The centrifugal pumps have respective pressed-sheet pump casings. The outside diameters of the impellers are not required to be increased in the high head section, and the outside diameters of the pump casings fall in a relatively small range.

## Claims

### Claim 1

A family of pumps of different pump heads and different nominal ratios of flow rates at the same speed, comprising:
a plurality of pump casings;
a plurality of motors; and
a plurality of impellers of different outer diameters, said plurality of impellers being mounted to output shafts of said plurality of motors and being positioned in said plurality of pump casings to produce said family of pumps in which at least one of said impellers is mounted to the output shaft of each of said motors of said family of pumps,
wherein a nominal ratio K of the flow rates of said pumps of said family of pumps at substantially the same rotational speed is about 1.6 and the nominal ratio of the pump heads thereof is about K.sup.1/2.