# US 12,760,727 B2 · Reciprocating pump

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- Number: US 12,760,727 B2
- Document ID: US12760727B2
- Status: Granted
- Kind: B2
- Application number: 19/150,029
- Filed: 2023-01-25
- Published: 2026-01-29
- Granted: 2026-10-13
- Earliest claimed: 2023-01-25
- Assignees: Ebara Corporation
- Applicants: Ebara Corporation
- Inventors: Hoechun Kim; Shuichiro Honda; Tetsuji Kasatani
- Web page: https://patentgrep.com/patent/US12760727B2

## CPC

- F04B 53/143: {Sealing provided on the piston}
- F04B 15/08: the liquids having low boiling points
- F04B 53/12: arranged in or on pistons
- F04B 2015/081: {Liquefied gases}
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)

## Abstract

The reciprocating pump includes a cylinder having an inflow chamber, a reset chamber, an intermediate chamber, and a pressurizing chamber therein, a piston located in the cylinder, a first seal, a second seal, and a third seal arranged in a gap between an inner surface of the cylinder and an outer surface of the piston, a suction check valve coupled to a suction port, an inlet check valve and an outlet check valve disposed in a piston passage, a discharge check valve coupled to a discharge port, and a leakage discharge check valve coupled to a leakage discharge port of the cylinder. The piston has a communication passage that provides a fluid communication between the piston passage and the intermediate chamber.

## Claims

### Claim 1

A reciprocating pump for delivering liquefied gas, comprising:
a cylinder having an inflow chamber, a reset chamber, an intermediate chamber, and a pressurizing chamber therein;
a piston located in the cylinder;
a first seal, a second seal, and a third seal arranged in a gap between an inner surface of the cylinder and an outer surface of the piston;
a suction check valve coupled to a suction port of the cylinder;
an inlet check valve and an outlet check valve disposed in a piston passage extending through the piston;
a discharge check valve coupled to a discharge port of the cylinder; and
a leakage discharge check valve coupled to a leakage discharge port of the cylinder,
wherein the leakage discharge port communicates with the reset chamber,
the inflow chamber and the reset chamber are partitioned by the first seal,
the reset chamber and the intermediate chamber are partitioned by the second seal,
the intermediate chamber and the pressurizing chamber are partitioned by the third seal, and
the piston has a communication passage that provides a fluid communication between the piston passage and the intermediate chamber.

### Claim 2 (depends on 1)

The reciprocating pump according to claim 1, further comprising a shaft seal device configured to seal a gap between a piston rod coupled to the piston and the cylinder.

### Claim 3 (depends on 1)

The reciprocating pump according to claim 1, wherein a diameter of the inflow chamber is larger than a diameter of the pressurizing chamber.

### Claim 4 (depends on 1)

The reciprocating pump according to claim 1, wherein the inflow chamber, the reset chamber, the intermediate chamber, and the pressurizing chamber are arranged in an order of the inflow chamber, the reset chamber, the intermediate chamber, and the pressurizing chamber along a longitudinal direction of the cylinder.