JPS5855033A - Gas mixing device - Google Patents

Abstract

PURPOSE:To obtain a gas mixing device of high mixing accuracy, by installing a differential pressure regulating valve in the piping and regulating and controlling a difference in passage resistance of plural gases by this differential pressure regulating valve. CONSTITUTION:To mix plural different gases, piping consisting of a pressure reducing valve 1, a flow meter 2, a differential pressure regulating valve 3 and a flow regulating valve 4 is made for a gas A, and similar piping 5-8 is made for a gas B. Respective pipe ends of downstream side are connected to the inlet side of a mixer 9, and a buffer tank 11 is connected to the outlet side through a valve 10 provided with speed control. As a difference in passage resistance between the two gases can be regulated and controlled by the differential pressure regulating valves 3, 7, a difference of mixing ratio setting value can be prevented and good mixing accuracy can be maintained at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a relatively inexpensive gas mixer for mixing a plurality of different gases, which achieves mixing accuracy without being affected by fluctuations in the amount of mixed gas used. IMPROVED GAS MIXING APPARATUS.

Conventionally, the mixing accuracy was strictly Kl! As a relatively inexpensive gas mixer that is not required, the tortoise shown in Fig. 1 is generally used. Fig. 1 is a general system diagram of a rounding system for mixing two types of gas. Now, when A gas and B gas are mixed at a certain ratio
) Adjusted to a constant pressure from K.

It passes through the flow needle (2) and reaches the mixer (9) with the flow rate adjusted by the flow rate adjustment valve (4). On the other hand, B gas is similarly adjusted to the same pressure as A gas by the pressure reducing valve (5), and the flow rate needle (6)
The flow rate is adjusted by a flow rate adjustment valve (8) K so that the mixing ratio becomes X, and the flow rate is reached at a mixer (9). Mixer (9
) The mixed gas mixed in the tank is supplied through the solenoid valve (2). This buffer tank I buffers fluctuations in the usage amount of the mixed gas, and when the flow rate fluctuates, it is attached to the buffer tank and controls the flow rate by opening and closing a solenoid valve (2) using a pressure switch.

However, in the above operation system, if the flow rate adjustment valves (4) and (8) are adjusted so that the mixture ratio at a specified point of a certain mixture pressure becomes X, the amount of mixed gas used increases or decreases, and the mixture pressure fluctuates. In some cases, the mixing ratio X deviates from the set value. This is due to the flow path resistance between the main KA gas pressure reducing valve (11) and the flow rate regulating valve (4), and the flow path resistance between the B gas pressure reducing valve (6) and the flow rate regulating valve (8).
This is caused by a difference in flow path resistance between the two.

In addition, since the solenoid valve (2) opens and closes instantaneously when controlling the gas flow rate, rapid pressure fluctuations occur on the upstream side of the solenoid valve, which has a negative impact on the lifespan of the equipment, and also has a negative effect on the structure of the solenoid valve. Not being pressured by Aya.

It is prone to leakage and therefore gas concentration fluctuations.

In order to eliminate this drawback, the present invention proposes a nine-gas mixing device in which the difference in flow path resistance between %A gas and B gas is adjusted and controlled using a differential pressure regulating valve to improve mixing accuracy.

That is, the present invention provides a pressure reducing valve, a flow rate needle, a differential pressure regulating valve,
A plurality of pipes with flow rate adjustment valves are connected in parallel to the inlet side of the tank, and the buffer is controlled via a speed control valve powered by the mixed gas pressure of the buffer tank or any gas pressure on the inlet side. The gist is that the tank was connected to the output side of the mixer.

Next, as an embodiment of the present invention, an apparatus for mixing two gases, A gas and B gas, will be described with reference to the drawings.

As shown in Fig. 2, A gas led from an air storage device such as a cylinder is passed through a pressure reducing valve (1), a flow meter (2), and a differential pressure regulating valve (3).
), a flow rate adjustment valve (4), and B gas is sent through a pipe having a pressure reducing valve (5), a flow rate needle (6), a differential pressure adjustment valve (7), and a flow rate adjustment valve (4). , each downstream tube end is connected to the inlet side of the mixer (91). A buffer tank (2) is connected to the outlet side of the mixer (9) via a valve with speed control. The speed control valve (to) is powered by the mixed gas pressure in the Bazza tank α or any gas pressure on the inlet side, and opens and closes according to fluctuations in the amount of mixed gas flowing out from the buffer tank O, and is a ball valve. use.

Now, the operation for mixing A gas and B gas at texture ratio X will be explained. A gas is adjusted to a constant pressure by the pressure reducing valve (1), passes through the flow meter (2) and the differential pressure adjustment valve (3), and the flow rate is adjusted by the flow rate adjustment valve (4), and then the mixer (9
). - The 10,000 B gas is similarly adjusted to the same pressure as the A gas by the pressure reducing valve (5), passes through the flow rate needle (6), the differential pressure regulating valve (7), and the mixture ratio is adjusted by the flow regulating valve (8) K. Adjust the flow rate so that it reaches X and reach mixer (1) K.

Both gases are mixed in the mixer (9) and supplied to the tank 7 (b) through a speed control valve 0.

A buffer tank buffers fluctuations in the amount of mixed gas used.
As the flow rate decreases, a nine-pressure switch installed in the buffer tank operates to open and close the valve (2) to control the flow rate as the mixed gas pressure within the buffer tank changes.

Relationship between mixed gas pressure and mixed gas flow rate 4c')tn.

Tests were conducted using the conventional device shown in FIG. 1 (indicated by the broken line) and the inventive device shown in FIG. 2 (indicated by the 9M! line). The result is K as shown in Figure 3.

No difference was found between the two.

Furthermore, the results of a test regarding the relationship between mixed gas pressure and mixing accuracy are shown in FIG. When using the conventional device shown by the broken line, it can be seen that when the mixed gas pressure fluctuates from the set point, the texture ratio changes and (ii) the gold precision decreases by 8 to 10%. On the other hand, in the case of using the inventive device shown by the solid line, even if the mixed gas pressure fluctuates, the change in the mixing ratio is small and the mixing accuracy is limited to a change of about 1 to 2 centimeters.

This invention, like Kamiayu, has a differential pressure regulating valve installed in the piping, which eliminates deviations in the mixing ratio set value due to deviations in flow path resistance and maintains good mixing accuracy at all times. In addition, a ball valve can be used as the speed control valve, and the leakage that occurs with solenoid valves does not occur.

[Brief explanation of drawings]

Figure 1 is a piping diagram of a conventional general gas mixing device. Fig. 2 is a piping diagram of an embodiment of the present invention, Fig. 3 is a chart showing the relationship between the mixed gas pressure and mixed gas flow rate of the conventional device (1m diameter) and the invented device (actual II), and Fig. 4 The same line is a chart showing the relationship between mixed gas pressure and mixing accuracy. In the figure, %1.5...pressure reducing valve, 2.6...flow meter, 3.
7...Differential pressure regulating valve, 4.8...Flow rate regulating valve, 9...
·mixer. lO...Valve with speed control, '11-/'
7A tank, 12... Solenoid valve. Applicant Kyodo Sanso Co., Ltd. Agent 1) Yoshihisa j7゛;;
°11j Figure 1 Figure 2 Figure 3 Figure 4 Suitable gas pressure? ! .

Claims (1)

[Claims] Multiple pipes with pressure reducing valves, flow needles, differential pressure regulating valves, and flow regulating valves are connected in parallel to the inlet side of the mixer, and the mixed gas pressure in the buffer tank or any gas pressure on the inlet side is used as the power source. Connect the buffer tank to the outlet side of the mixer through a valve with speed control to the nine gas mixing device.