Piston ring, reciprocating compressor, method for selecting piston ring and method for evaluating life of piston ring

Patent metadata

Field	Value
Publication number	US-11441682-B2
Application number	US-202016837538-A
Country	US
Kind code	B2
Filing date	Apr 1, 2020
Priority date	Apr 26, 2019
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

A piston ring is used for a reciprocating compressor. In the piston ring, polytetrafluoroethylene and polyetheretherketone or polyimide account for 50% or more by mass in total. The piston ring does not contain polyphenylene sulfide. The piston ring has a tensile strength within a range of more than 15 MPa and less than 100 MPa.

First claim

The invention claimed is:

1. A piston ring used for a reciprocating compressor, wherein
polytetrafluoroethylene, and one selected from polyetheretherketone and polyimide account for 50% or more by mass in total,
the piston ring does not contain polyphenylene sulfide,
the piston ring has a tensile strength within a range of more than 15 MPa and less than 100 MPa.

2. The piston ring according to claim 1 , having a tensile strength of 55 MPa or less.

3. A reciprocating compressor configured to pressurize hydrogen gas to a predetermined pressure in a hydrogen station, the reciprocating compressor comprising:
a cylinder provided with a compression chamber into which hydrogen gas is sucked;
a piston that is disposed in the cylinder and is reciprocated in the cylinder to change a volume of the compression chamber; and
the piston ring according to claim 1 , being attached to an outer peripheral portion of the piston to seal a gap between the outer peripheral portion of the piston and an inner wall surface of the cylinder.

4. A reciprocating compressor configured to pressurize hydrogen gas to a predetermined pressure in a hydrogen station, the reciprocating compressor comprising:
a cylinder provided with a compression chamber into which hydrogen gas is sucked;
a piston that is disposed in the cylinder and is reciprocated in the cylinder to change a volume of the compression chamber; and
the piston ring according to claim 2 , being attached to an outer peripheral portion of the piston to seal a gap between the outer peripheral portion of the piston and an inner wall surface of the cylinder.

5. A method for selecting a piston ring used for a reciprocating compressor, the method comprising the step of:
selecting a piston ring in which polytetrafluoroethylene, and one selected from polyetheretherketone and polyimide account for 50% or more by mass in total, polyphenylene sulfide is not contained and a tensile strength is within a range of more than 15 MPa and less than 100 MPa, as a piston ring to be attached to an outer peripheral portion of a piston.

6. A method for evaluating life of a piston ring used in a reciprocating compressor, the method comprising the steps of:
investigating a correlation between an operating time of the reciprocating compressor and pressure in a space in which pressure can rise due to leakage of compressed hydrogen gas through a gap between the piston ring and a cylinder;
determining the operation time when the pressure in the space reaches a predetermined threshold based on the correlation; and
evaluating the determined operation time as the life of the piston ring.

Assignees

• Kobe Steel Ltd

Inventors

• Ootsuka Tomohiro
• Kanei Naofumi

Classifications

• F04B39/0005

  adaptations of pistons · CPC title

• F16J9/28 Primary

  of non-metals · CPC title

• F16J9/26 Primary

  characterised by the use of particular materials · CPC title

• F04B53/143

  Sealing provided on the piston · CPC title

• F04B39/00

  Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00 · CPC title