PRESSURE TYPE FLOW RATE CONTROL DEVICE

• US 20120298220A1
• Filed: 05/30/2012
• Published: 11/29/2012
• Est. Priority Date: 12/01/2009
• Status: Active Grant

• Current Assignee: Fujikin Incorporated
• Original Assignee: Fujikin Incorporated
• Inventors: NAGASE, Masaaki, DOHI, Ryousuke, IKEDA, Nobukazu, NISHINO, Kouji, HIDAKA, Atsushi
• Granted Patent: US 9,574,917 B2
• Time in Patent Office: Days
• US Class Current: 137/468
• CPC Class Codes: G01F 1/363 with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 15/024 involving digital counting
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10T 137/7737 Thermal responsive
• CPC Class Codes: Y10T 137/776 Control by pressures across flow line valve
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

A pressure type flow rate control device provides flow rate control for gas at 100-500° C. with an error not more than 1.0% F.S. The pressure type flow rate control device includes a valve body with a fluid passage, a valve portion interposed in the passage, a valve drive unit driving the valve portion to open/close the passage, a restriction mechanism on the downstream side of the valve portion in the passage, a temperature detector detecting gas temperature between the valve portion and restriction mechanism, a pressure detector detecting gas pressure between the valve portion and restriction mechanism, and an arithmetic control device controlling flow rate of gas in the restriction mechanism based on values detected by the temperature detector and the pressure detector, wherein the temperature detector is inserted in an attachment hole of the valve body at a position just above an outlet side fluid passage.

Claims

1. A pressure type flow rate control device comprising:

(a) a valve body in which a fluid passage is formed;

(b) a valve portion interposed in the fluid passage;

(c) a valve drive unit operably connected to drive the valve portion, wherein the valve drive unit opens and closes the fluid passage by driving the valve portion;

(d) a restriction mechanism provided on the downstream side of the valve portion in the fluid passage;

(e) a temperature detector disposed to detect a gas temperature between the valve portion and the restriction mechanism;

(f) a pressure detector disposed to detect a gas pressure between the valve portion and the restriction mechanism; and

(g) an arithmetic control device that arithmetically controls a flow rate of a gas distributed in the restriction mechanism based on detected values of temperature and pressure detected by the temperature detector and the pressure detector, respectively, and the arithmetic control device controls the valve drive unit, wherein

the temperature detector is inserted in an attachment hole opened inward from an upper surface side of the valve body at a position just above an outlet side fluid passage between the valve portion and the restriction mechanism.

2. The pressure type flow rate control device according to claim 1, wherein the temperature detector is a thermistor temperature detector, and the arithmetic control device includes

i. a detected value correcting element that corrects an error of a temperature detected value detected by the thermistor temperature detector;

and

ii. a pressure correcting element that corrects a pressure value detected by the pressure detector based on the corrected value corrected by the detected value correcting element.

3. The pressure type flow rate control device according to claim 2, wherein the detected value correcting element corrects an error of a gas temperature detected by the thermistor temperature detector based on temperature characteristics relating to detected temperatures detected by the thermistor temperature detector.

4. The pressure type flow rate control device according to claim 3, wherein the temperature characteristics are related by an approximation equation obtained from two or more different temperatures.

5. The pressure type flow rate control device according to claim 4, wherein the approximation equation is the following Equation,

Y=aX+b 

 

(Equation

     1),

wherein Y is a temperature corresponding to a-detected temperature detected by the thermistor temperature detector, X is a temperature corresponding to a gas measured temperature measured by a thermocouple or a platinum resistance temperature detector, and a and b are constants determined for each individual thermistor temperature detector.

6. The pressure type flow rate control device according to claim 5, wherein in Equation 1, the assumption of Y=X in the range of 20 to 26°

C. is utilized to calculate the constants a and b.

7. The pressure type flow rate control device according to claim 1, wherein the valve body comprises

i. a valve main body;

ii. a fluid inlet side connecting portion having a fluid inlet side joint fixed to one side surface of the valve main body; and

iii. a fluid outlet side connecting portion having a fluid outlet side joint fixed to the other side surface of the valve main body, and the valve main body is configured so that a filter holding portion is provided at a position opposed to the fluid inlet side connecting portion of the valve main body, and a restriction mechanism holding portion is provided at a position opposed to the fluid outlet side connecting portion of the valve main body.

8. The pressure type flow rate control device according to claim 1, further comprising:

(h) a heater for heating that is provided on an outer side surface of the valve body for keeping temperature of a gas distributed in the fluid passage at a set temperature.

9. The pressure type flow rate control device according to claim 8, wherein the heater is a tabular heater or a jacket heater that heats the valve body to 50°

C. to 500°

C.

10. The pressure type flow rate control device according to claim 1, wherein the attachment hole for the temperature detector is provided just above the outlet side fluid passage and has a predetermined depth, and a distance between a bottom surface of the attachment hole and an upper wall surface of the outlet side fluid passage is 0.1 to 5.0 mm.

11. The pressure type flow rate control device according to claim 1, wherein the pressure type flow rate control device has flow rate control accuracy in which flow rate error becomes 1.0% F.S. or less in a gas temperature range of 50°

C. to 500°

C.

12. The pressure type flow rate control device according to claim 1, wherein the valve drive unit is a multilayer piezoelectric element, and a cylinder holder that holds the valve drive unit is attached to the valve body, and the temperature detector is fixed to the valve body by placing a spacer above the temperature detector inserted in the attachment hole and pressing and fixing an upper surface of the spacer by a flange portion provided on the cylinder holder.

13. The pressure type flow rate control device according to claim 1, wherein the pressure detector and the temperature detector are configured separately from the valve body, and are combined with the valve body.

14. The pressure type flow rate control device according to claim 1, wherein the temperature detector is a thermistor temperature detector, a platinum resistance temperature detector, or a thermocouple.