JPH0449687Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mass flow controller that controls fluid flow rate.

[Conventional technology]

A mass flow controller generally includes a flow measurement channel having a sensor section for detecting the fluid flow rate between a fluid inlet and a fluid outlet formed on a metal base, and a fluid control valve for controlling the fluid flow rate. However, since there are a wide variety of types of gas flowing through the mass flow controller, the flow path may become clogged due to impurities contained in the flowing gas.

If a blockage occurs in the flow path within the base, the mass flow controller must be inspected, cleaned, repaired, or replaced with another one, but this may result in the flow of gas that is harmful to the human body. Therefore, during the inspection, etc., the gas in the flow path is purged in advance with an inert purge gas such as nitrogen gas.

FIG. 3 shows a means for performing purging in a conventional mass flow controller, and FIG. A purge flow path 34 is provided, and when the mass flow controller 32 becomes clogged, a purge valve 33 is opened to allow purge gas from a purge gas source 35 to flow into the purge flow path 34.

B in the same figure shows the mass flow controller 32.
Three-way valves 36 and 36 are provided on the upstream and downstream sides of the
In addition, the three-way valves 36 and 36 are connected by a purge passage 34, and the operation is the same as that shown in A above.

In addition, in Figure C, on-off valves 37, 37 are provided on the upstream and downstream sides of the mass flow controller 32, and a rotor-type flowmeter 39 with a needle valve 38 is provided between the on-off valves 37, 37 to control the purge flow. It is shown that the gas flow rate flowing through the passage 34 can be monitored.

Note that 40 and 41 are stop valves.

[Problem that the invention attempts to solve]

However, in any of the means shown in FIGS. 3A, B, and C, the purge flow path 34 is provided outside the mass flow controller 32, and the purge valve 33, three-way valves 36, 36, on-off valves 37, 37 Since it is provided separately from the mass flow controller 32, the piping system becomes large-scale and costs are high.

Furthermore, even if the purge valve 33 and the like are opened to flow the purge gas into the purge channel 34, the harmful gas remaining in the mass flow controller 32 cannot be completely purged, and the mass flow controller 32 cannot be completely purged. During replacement, the harmful gas was released into the atmosphere, creating a safety problem. In order to solve this problem, for example, as shown in FIG. It is conceivable to suck it out, but the configuration would be complicated and the cost would be high.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to provide a mass flow controller that is highly safe and inexpensive without requiring complicated piping.

[Means for solving problems]

In order to achieve the above-mentioned object, the mass flow controller according to the present invention includes a purge main flow whose one end is connected between a fluid inlet and a flow rate measurement channel, and the other end is connected between a fluid control valve and a fluid outlet. forming a purge flow path in the base body, the communication path having one end connected between the flow rate measurement flow path and the fluid control valve and the other end connected to the purge main flow path;
The present invention is characterized in that purge control valves are provided on the upstream and downstream sides of the connection point of the main purge channel with the communication path and in the communication path, respectively.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 and FIG. 2 are a diagram showing the flow path configuration in the mass flow controller MFC according to the present invention, and a perspective view showing the external shape, respectively.

In FIGS. 1 and 2, reference numeral 1 denotes a base body consisting of two block bodies 1A and 1B. Block 1
A fluid inlet 2 is formed on one side of A, and a fluid outlet 3 is formed on the other side. Numerals 4 and 6 are joint members attached to the fluid inlet 2 and the fluid outlet 3, respectively.

Between a fluid inlet 2 and a fluid outlet 3 formed in the block body 1A, a flow rate measuring channel 7 having a sensor section 6 for detecting the fluid flow rate and a fluid control valve 8 for controlling the fluid flow rate are provided. A flow rate control channel 9 having a flow rate control channel 9 is formed. Then, the flow rate measurement channel 7
consists of a sensor flow path 10 and a bypass flow path 11 that are connected in parallel to each other, and the sensor section 6 is provided in the sensor flow path 10. Note that A and B are a branch point and a confluence point of the sensor flow path and the bypass flow path 11, respectively. Further, 12 is a block body which is connected to the block body 1A by appropriate means, and the sensor flow path 10 is formed within the block body 12.

A purge passage 15 consisting of a main purging passage 13 and a communication passage 14 is formed in the block body 1B, which is connected to the block body 1A by, for example, a screw. The main purge channel 13 is provided such that one end 13a thereof is connected between the fluid inlet 2 and the branch point A, and the other end 13b is connected between the fluid control valve 8 and the fluid outlet 3. ing. Further, the communication passage 14 is provided such that one end 14a thereof is connected between the merging point B and the fluid control valve 8, and the other end 14b is connected to the main flow passage 13 for purging.

A communication path 14 of the main flow path 13 for purging is provided.
Purge control valves 16 and 1 are provided on the upstream and downstream sides of the connection point 14b and in the communication passage 14, respectively.
7 and 18 are provided. 16a, 17a, 18a
are the purge control valves 16, 17, 18, respectively.
This is an adjustment member for adjusting the opening degree of the opening.

19 is a gas source containing gas to be supplied; 20
is a purge gas source containing an inert purge gas such as nitrogen gas, and 21 and 22 are stop valves. 23 is an upstream pipe, and 24 is a downstream pipe connected to a downstream device such as a semiconductor manufacturing device or an analyzer.

In the above configuration, the base body 1 is composed of two block bodies 1A and 1B;
Needless to say, it may be constructed from two blocks. Further, in the above configuration, the sensor flow path 10 and the bypass flow path 1 are connected in parallel to each other.
1 forms a flow rate measurement channel 7,
The flow rate measurement channel 7 may be configured by only the sensor channel 10. Such a device is used for applications where the fluid flow rate is relatively small.

Next, the mass flow controller with the above configuration
The operation of MFC will be explained.

When clogging occurs in the flow rate control channel 9 including the fluid control valve 8, the purge control valves 17 and 18
The inside of the mass flow controller MFC may be purged by opening the valve, closing the stop valve 21, opening the stop valve 22, and flowing the purge gas. In addition, in the above, purge control 1
By appropriately adjusting the opening degree of either or both of 7 and 18, the necessary gas flow rate can be adjusted, and the flow rate at that time can be confirmed in the sensor section 6, so that the downstream The gas of the gas source 19 required by the side equipment can be supplied.

In addition, when clogging occurs in the sensor flow path 10 and the bypass flow path 11, the purge control valve 16,
17 in the open state and flow the purge gas in the same manner as above to control the mass flow controller.
Just purge inside MFC.

Furthermore, if the location of the clogging is unknown, all purge control valves 16, 17, and 18 may be opened to allow the purge gas to flow.

[Effects of the invention] As explained above, the mass flow controller according to the invention has one end connected between the fluid inlet and the flow rate measurement channel, and the other end connected between the fluid control valve and the fluid outlet. A purge flow path is formed in the base body, comprising a purge main flow path and a communicating path, one end of which is connected between the flow rate measurement flow path and the fluid control valve, and the other end of which is connected to the purge main flow path. However, since purge control valves are provided on the upstream and downstream sides of the connection point between the main purge channel and the communicating path, as well as in the communicating path, complicated external piping is not required and the piping system is compact. And it's cheap.
Further, by appropriately opening and closing the purge control valve depending on the location where the clogging occurs, harmful gases remaining inside can be reliably and completely purged, improving safety. Furthermore, even if the fluid control valve becomes clogged, a predetermined gas can be supplied to the downstream device by appropriately opening and closing the purge control valve.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention, Figure 1 is a diagram showing the flow path configuration, Figure 2 is a perspective view, and Figures A, B, and C are for explaining the prior art. This is the diagram. DESCRIPTION OF SYMBOLS 1...Base body, 2...Fluid inlet, 3...Fluid outlet, 6...Sensor part, 7...Flow rate measurement channel, 8...
...Fluid control valve, 9...Flow rate control channel, 13...Purge main channel, 14...Communication path, 14b...Connection point, 15...Purge channel, 16, 17, 18...
...Purge control valve, MFC...Mass flow controller.

Claims (1)

[Scope of utility model registration request] Between the fluid inlet and fluid outlet formed in the base,
A mass flow controller including a flow rate measurement channel having a sensor section for detecting a fluid flow rate and a flow rate control channel having a fluid control valve for controlling the fluid flow rate, wherein one end is connected to the fluid inlet and the flow rate measurement channel. a main purge channel connected between the flow path and the other end connected between the fluid control valve and the fluid outlet, and one end connected between the flow rate measurement flow path and the fluid control valve. A purge flow path including a communication path whose other end is connected to the main purge flow path is formed in the base body, and the purge flow path is formed in the base body, and the purge flow path is formed on the upstream and downstream sides of the connection point of the main purge flow path with the communication path, and A mass flow controller characterized in that each communication passage is provided with a purge control valve.