# US 7,997,088 B2 · Hybrid spool valve for multi-port pulse tube

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- Number: US 7,997,088 B2
- Document ID: US7997088B2
- Status: Granted
- Kind: B2
- Application number: 11/719,697
- Filed: 2005-01-13
- Published: 2009-06-18
- Granted: 2011-08-16
- Earliest claimed: 2005-01-13
- Assignees: Sumitomo Heavy Industries, Ltd.; SHI-APD Cryogenics, Inc.
- Inventors: Ralph C. Longsworth
- Web page: https://patentgrep.com/patent/US7997088B2

## CPC

- F25B 9/145: {pulse-tube cycle}
- F16K 31/041: {for rotating valves (F16K31/055 takes precedence)}
- F25B 9/10: with several cooling stages
- F25B 2309/002: with parallel working cold producing expansion devices in one circuit
- F25B 2309/006: using a distributing valve of the rotary type
- F25B 2309/1408: Pulse-tube cycles with pulse tube having U-turn or L-turn type geometrical arrangements
- F25B 2309/1411: Pulse-tube cycles characterised by control details, e.g. tuning, phase shifting or general control
- F25B 2309/14181: the valves being of the rotary type
- F25B 2309/14241: Pulse tubes with basic schematic including an orifice reservoir multiple inlet pulse tube
- F25B 2309/1427: Control of a pulse tube
- Y10T 137/87032: Rotary concentric valves
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)}
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The problems of reducing the torque required to turn the valve, eliminating wear dust, and extending the life of the valves in Gifford McMahon (G-M) type multi-port pulse tube refrigerators are solved by using a rotary spool valve having radial clearance to control flow to and from the regenerator, and using face seal ports on the end of the spool to control flow to and from the pulse tubes.

## Claims

### Claim 1

A multi-ported rotary spool valve for a G-M pulse tube refrigerator, comprising:
a close fitting rotating spool mounted inside a fixed sleeve having multiple radial ports; and
an end face on said rotating spool including a flat face in sliding contact with the flat face of a valve plate having multiple axial ports, wherein
said sliding contact being maintained by virtue of a gas pressure being higher on an end of the spool opposite the ports than an average pressure on an end of the spool with the ports, and
gas flows to a regenerator of said pulse tube through said radial ports and gas flows to a warm end of one or more pulse tubes through said axial ports.

### Claim 2 (depends on 1)

The rotary spool valve of claim 1 where two or more cooling cycles are executed during each revolution of the spool.

### Claim 3 (depends on 1)

The rotary spool valve of claim 1 where the G-M type pulse tube refrigerator is a two stage, four valve type pulse tube.

### Claim 4 (depends on 1)

The rotary spool valve of claim 1 where high pressure ports for flow to pulse tubes are located on one track and low pressure ports for flow from the pulse tubes are located on a second track.

### Claim 5 (depends on 3)

The rotary spool valve of claim 3 where timing for flow to a second stage of the two stage is different than timing for flow to a first stage of the two stage.

### Claim 6 (depends on 1)

The rotary spool valve of claim 1 where the spool, sleeve, and valve plate are ceramic.

### Claim 7 (depends on 6)

The rotary spool valve of claim 6 where the ceramic is alumina.

### Claim 8 (depends on 1)

The rotary spool valve of claim 1 where the average radial clearance between the rotating spool and stationary sleeve is greater than 0 and less than 5 microns.