# US 10,309,810 B2 · Pressure type flowmeter

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- Number: US 10,309,810 B2
- Document ID: US10309810B2
- Status: Granted
- Kind: B2
- Application number: 15/814,041
- Filed: 2017-11-15
- Published: 2018-05-17
- Granted: 2019-06-04
- Earliest claimed: 2016-11-17
- Assignees: HORIBA STEC, Co., Ltd.
- Applicants: HORIBA STEC, Co., Ltd.
- Inventors: Takehisa Hataita; Hideaki Miyamoto
- Web page: https://patentgrep.com/patent/US10309810B2

## CPC

- G01F 1/383: {with electrical or electro-mechanical indication}
- G01F 1/36: the pressure or differential pressure being created by the use of flow constriction
- G01L 9/0072: {using variations in capacitance}
- G01L 13/06: using electric or magnetic pressure-sensitive elements
- G01L 15/00: Devices or apparatus for measuring two or more fluid pressure values simultaneously
- G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## Abstract

In order to solve a problem occurring in a capacitance type pressure sensor adapted to measure absolute pressure, and thereby reduce error, a pressure type flowmeter includes a fluid resistance part in a flow path through which fluid flows and measures a flow rate by detecting the upstream and downstream pressures of the fluid resistance part. Respective pressure sensors for detecting the upstream and downstream pressures are configured to be gauge pressure sensors. Each of the gauge pressure sensors is a capacitance type pressure sensor adapted to measure gauge pressure by detecting a change in the capacitance between a diaphragm displaceable by pressure and a fixed electrode and has a main body part that supports the fixed electrode and the diaphragm and forms a space between them. Further, the internal space is adapted to communicatively connect to the outside through a communicative connection part.

## Claims

### Claim 1

A pressure type flowmeter adapted to include a fluid resistance part in a flow path through which fluid flows and measure a flow rate by detecting upstream side pressure and downstream side pressure of the fluid resistance part, wherein
an upstream pressure sensor for detecting the upstream side pressure and a downstream pressure sensor for detecting the downstream side pressure are capacitance type pressure sensors each of which is adapted to measure gauge pressure by detecting a change in capacitance between a diaphragm displaceable by pressure and a fixed electrode and has a main body part that supports the fixed electrode and the diaphragm and forms an internal space between them, and
the internal space of each pressure sensor is opened to an atmosphere through a communicative connection part.

### Claim 2 (depends on 1)

The pressure type flowmeter according to claim 1, wherein
for each pressure sensor, the communicative connection part is formed in the main body part.

### Claim 3 (depends on 1)

The pressure type flowmeter according to claim 1, wherein for each pressure sensor:
the main body part and the diaphragm are joined together, and
an unjoined part is formed in a part between the main body part and the diaphragm, and the unjoined part forms the communicative connection part.

### Claim 4 (depends on 1)

The pressure type flowmeter according to claim 1, wherein
for each pressure sensor, a groove is formed in a diaphragm joining surface of the main body part, and the groove forms the communicative connection part.

### Claim 5 (depends on 1)

The pressure type flowmeter according to claim 1, wherein
the internal space of the upstream pressure sensor and the internal space of the downstream pressure sensor connect to a common external space through the respective communicative connection parts to thereby be opened to the atmosphere.