# US 7,607,356 B2 · Pirani vacuum gauge

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- Number: US 7,607,356 B2
- Document ID: US7607356B2
- Status: Granted
- Kind: B2
- Application number: 11/630,868
- Filed: 2005-11-07
- Published: 2008-05-22
- Granted: 2009-10-27
- Earliest claimed: 2004-11-24
- Assignees: Ulvac, Inc.
- Inventors: Takeshi Miyashita; Naoki Takahashi
- Web page: https://patentgrep.com/patent/US7607356B2

## CPC

- G01L 21/12: measuring changes in electric resistance of measuring members, e.g. of filaments; Vacuum gauges of the Pirani type
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

A Pirani vacuum gauge in which dependency of temperature of a filament on variation of gas pressure is raised and the gas pressure can be measured with high accuracy. The Pirani vacuum gauge includes a cylindrical body 2 in which the interior communicates with a space to be measured for pressure; a filament 1 enclosed in the cylindrical body 2; and a pipe 7 surrounding the filament 1 in the cylindrical body, the least distance between the facing inner walls of the pipe being equal to less than 6 mm and the pipe 7 covering more than 80% of the length of the filament 1.

## Claims

### Claim 1

A Pirani vacuum gauge comprising:
a cylindrical body in which the interior communicates with a space to be measured for pressure;
a filament included in said cylindrical,
a pipe surrounding said filament in said cylindrical body whereby said filament passes through a central axis of said pipe, the least distance between facing inner walls of said pipe being equal to less than 4 mm and said pipe covering more than 80% of the length of said filament; and a filament support included in said cylindrical body and supporting one end of said filament.

### Claim 2 (depends on 1)

A Pirani vacuum gauge according to claim 1 in which said pipe is thermally conductive.

### Claim 3 (depends on 2)

A Pirani vacuum gauge according to claim 2 in which a temperature sensor is attached onto said pipe whereby a pressure indicating value of said gauge is corrected on the basis of the output of said temperature sensor.

### Claim 4 (depends on 3)

A Pirani vacuum gauge according to claim 3 in which said filament is comprised of platinum and said pipe is comprised of stainless.

### Claim 5 (depends on 3)

A Pirani vacuum gauge according to claim 3 in which said filament is comprised of platinum and said pipe is comprised of nickel.

### Claim 6 (depends on 2)

A Pirani vacuum gauge according to claim 2 in which said filament is comprised of platinum and said pipe is comprised of stainless.

### Claim 7 (depends on 2)

A Pirani vacuum gauge according to claim 2 in which said filament is comprised of platinum and said pipe is comprised of nickel.

### Claim 8 (depends on 1)

A Pirani vacuum gauge according to claim 1 in which a temperature sensor is attached onto said pipe whereby a pressure indicating value of said gauge is corrected on the basis of the output of said temperature sensor.

### Claim 9 (depends on 1)

A Pirani vacuum gauge according to claim 1 in which said filament is comprised of platinum and said pipe is comprised of stainless.

### Claim 10 (depends on 1)

A Pirani vacuum gauge according to claim 1 in which said filament is comprised of platinum and said pipe is comprised of nickel.