Flow rate control apparatus, flow rate control method, and program recording medium

• US 10,545,514 B2
• Filed: 07/30/2018
• Issued: 01/28/2020
• Est. Priority Date: 07/31/2017
• Status: Active Grant

• Current Assignee: Horiba STEC, Co., Ltd. (Horiba Limited)
• Original Assignee: Horiba STEC, Co., Ltd. (Horiba Limited)
• Inventors: Yasuda, Tadahiro, White, Bill, Lowery, Patrick, Gundlach, Maximilian, Owens, Ryan
• Primary Examiner(s): Le, Minh Q
• Application Number:
  US16/048,750
• Publication Number:
  US 20190033896A1
• Time in Patent Office: 547 Days
• Field of Search: 1374875, 137 9, 137 12, 137488
• CPC Class Codes: G01F 1/363 with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 15/005 Valves valves in general F16K
• CPC Class Codes: G01F 22/02 involving measurement of pressure
• CPC Class Codes: G01F 25/10 of flowmeters
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37371 Flow
• CPC Class Codes: G05D 7/0647 the plurality of throttling means being arranged in series
• CPC Class Codes: G05D 7/0664 the plurality of throttling means being arranged for the control of a plurality of diverging flows from a single flow G05D7/0652 takes precedence; ratio control G05D11/13

Abstract

Provided is a flow rate control apparatus that includes a flow restrictor, a downstream side valve, a downstream side pressure sensor, first and second flow rate calculators, and a flow rate controller. The downstream side valve is disposed downstream of the flow restrictor in a flow path. The downstream side pressure sensor measures a pressure between the flow restrictor and the downstream side valve. The first flow rate calculator calculates a first flow rate of fluid flowing through the flow restrictor. The second flow rate calculator calculates a second flow rate of fluid flowing out of the downstream side valve on the basis of the first flow rate and the temporal variation in downstream side pressure measured by the downstream side pressure sensor. The flow rate controller controls the downstream side valve on the basis of a set flow rate and the second flow rate.

Claims

1. A flow rate control apparatus comprising:

a flow restrictor disposed in a flow path;

a downstream side valve disposed downstream of the flow restrictor;

a downstream side pressure sensor to measure a pressure in a volume of the flow path between the flow restrictor and the downstream side valve;

a first flow rate calculator to calculate a first flow rate of fluid flowing through the flow restrictor;

a second flow rate calculator to calculate a second flow rate of fluid flowing out of the downstream side valve on a basis of the first flow rate and a temporal variation in a downstream side pressure measured by the downstream side pressure sensor; and

a flow rate controller to control the downstream side valve on a basis of a set flow rate and the second flow rate.

2. The flow rate control apparatus according to claim 1, wherein the second flow rate calculator comprises:

a variation calculation section to calculate the temporal variation in downstream side pressure, and

a flow rate computing section to calculate the second flow rate on a basis of a difference between the first flow rate and a converted flow rate calculated from a temporal variation in downstream side pressure.

3. The flow rate control apparatus according to claim 1, further comprising:

an upstream side valve disposed upstream of the flow restrictor;

an upstream side pressure sensor to measure a pressure in a volume of the flow path between the upstream side valve and the flow restrictor; and

a pressure controller to control the upstream side valve on a basis of a set pressure and an upstream side pressure measured by the upstream side pressure sensor.

4. The flow rate control apparatus according to claim 3, wherein the first flow rate calculator is designed to calculate the first flow rate of fluid flowing through the flow restrictor on a basis of the upstream side pressure and the downstream side pressure.

5. The flow rate control apparatus according to claim 1, further comprising:

a diagnosis section to diagnose a presence or absence of abnormality by comparing the first flow rate and the second flow rate in a state in which the downstream side valve is closed.

6. The flow rate control apparatus according to claim 1, further comprising:

a flow rate detection mechanism to output a detection signal according to the first flow rate of fluid flowing through the flow restrictor,

wherein the first flow rate calculator is designed to calculate the first flow rate on a basis of a detection signal outputted from the flow rate detection mechanism.

7. A flow rate control method using a flow rate control apparatus comprising a flow restrictor disposed in a flow path, a downstream side valve disposed downstream of the flow restrictor, and a downstream side pressure sensor to measure a pressure in a volume of the flow path between the flow restrictor and the downstream side valve,

the flow rate control method comprising:

a first flow rate calculation step of calculating a first flow rate of fluid flowing through the flow restrictor;

a second flow rate calculation step of calculating a second flow rate of fluid flowing out of the downstream side valve on a basis of the first flow rate and a temporal variation in a downstream side pressure measured by the downstream side pressure sensor; and

a flow rate control step of controlling the downstream side valve on a basis of a set flow rate and the second flow rate.

8. A program recording medium having recorded therein a program used for a flow rate control apparatus comprising a flow restrictor disposed in a flow path, a downstream side valve disposed downstream of the flow restrictor, and a downstream side pressure sensor to measure a pressure in a volume of the flow path between the flow restrictor and the downstream side valve,

the program recording medium causing a computer to function as

a first flow rate calculator to calculate a first flow rate of fluid flowing through the flow restrictor;

a second flow rate calculator to calculate a second flow rate of fluid flowing out of the downstream side valve on a basis of the first flow rate and the temporal variation in a downstream side pressure measured by the downstream side pressure sensor; and

a flow rate controller to control the downstream side valve on a basis of a set flow rate and the second flow rate.