JPH084101Y2 - Gas mixing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a gas mixing device, and more particularly to a gas mixing device for mixing two kinds of gases to obtain a gas having a predetermined mixing ratio.

[Outline of device]

The flow rate of each of the two kinds of gas is detected by a flow meter provided in each of the two kinds of gas supply pipes, and the concentration of the gas is calculated from the detected values by a calculation means. By adjusting the flow rate adjusting valves provided in the respective gas supply paths by the control means including the comparator and the operational amplifier, the flow rates are adjusted so that the flow rate ratio of the two kinds of gas matches the target concentration. In this way, the concentration of the mixed gas can be finely adjusted and the offset from the set concentration is prevented from occurring.

[Conventional technology]

For example, in order to obtain a mixed gas by mixing hydrogen gas and nitrogen gas, a gas mixing device using a capillary flow rate ratio mixing method is provided. This device adopts a capillary type flow ratio mixing method to generate a mixed gas at a constant ratio, and it is possible to change the supply amount of the mixed gas without changing the mixing ratio of hydrogen and nitrogen. I am allowed to do it.

[Problems to be solved by the invention]

In the conventional gas mixing device, the resolution is about 2% because the gas is mixed by a mechanical method.
However, there is a drawback that the mixed gas concentration cannot be finely adjusted. Further, since the control of the concentration of the mixed gas is an open loop control, when a pressure fluctuation or a flow rate change occurs, the concentration of the mixed gas is offset from the set concentration at a constant rate and a deviation occurs in the concentration of the mixed gas. Furthermore, because mechanical control is performed, there is the drawback that daily usage reports, monthly totals, data collection and storage of flow rates and mixing ratios cannot be collected, and gas usage cannot be managed. is there.

The present invention has been made in view of such problems, and it is possible to finely adjust the concentration of a mixed gas, no offset occurs in the gas concentration, and the amount of gas used is easily controlled. It is an object of the present invention to provide a gas mixing device designed to be obtained.

[Means for solving problems]

The present invention relates to a device for mixing two kinds of gas to obtain a gas having a predetermined mixing ratio, wherein a flow rate adjusting valve connected to each of the two kinds of gas supply paths and a supply path of the two kinds of gas are provided. A flowmeter connected to each of the two, and the detection values of the flowmeters of the two types of gas are input, calculation means for calculating the concentration of the mixed gas, the target value of the concentration and the concentration calculated by the calculation means. And a control means for controlling the flow rate adjusting valves of the two types of gas so as to perform mutually opposite operations according to the output of the comparator. The present invention relates to a gas mixing device provided.

[Action]

Therefore, the flow rates of the two kinds of gases flowing in the respective supply paths are detected by the corresponding flow meters, and the concentration of the mixed gas is calculated by the calculation means to which the detected values of these flow meters are input. Then, the density of the calculation result is compared with the target value in the comparator, and the comparator generates an output according to the deviation. Therefore, according to the output of this comparator, the control means controls the flow rate adjusting valves of the two kinds of gas so that the flow rate adjusting valves of the two kinds of gas are opposite to each other, so that the concentration of the mixed gas is controlled to match the target value by the closed loop control. It

〔Example〕

The drawing shows a gas mixing apparatus according to an embodiment of the present invention. This mixing apparatus relates to an apparatus for mixing nitrogen gas and oxygen gas to obtain a mixed gas having an oxygen concentration of a predetermined value. This equipment is a nitrogen gas supply pipe 11
And an oxygen gas supply pipe 12. These supply pipes 1
A nitrogen gas inlet 13 and an oxygen gas inlet 14 are connected to the upstream end portions of 1 and 12, respectively. Further, the downstream sides of these supply pipes 11 and 12 are joined to the mixed gas take-out pipe 15 side, and a mixed gas outlet 16 is provided at the end of the take-out pipe 15. A flow rate adjusting valve 17 and a flow meter 18 are connected to the nitrogen gas supply pipe 11. On the other hand, the oxygen gas supply pipe 12 has a flow rate adjusting valve.
19 and a flow meter 20 are attached.

The flowmeters 18, 20 attached to the nitrogen gas supply pipe 11 and the oxygen gas supply pipe 12, respectively, are connected to a calculator 23. The calculator 23 is adapted to calculate the concentration of the mixed gas obtained by mixing the two kinds of gas. A recorder 24 is connected to the arithmetic unit 23. This recorder 24 is a recording paper
With 25, for example, the concentration of the mixed gas is recorded. The output of the computing unit 23 is supplied to the comparator 26. The comparator 26 compares the output of the computing unit 23 with the target value. The output of the comparator 26 is amplified by the operational amplifier 27. The operational amplifier 27 controls the regulating valves 17 and 19 connected to the supply pipes 11 and 12, respectively.

In the above configuration, the flow rate of nitrogen gas in the nitrogen gas supply pipe 11 is detected by the flow meter 18. The flow rate of oxygen gas flowing through the oxygen gas supply pipe 12 is detected by the flow meter 20. Then, the detection values of these flow meters 18, 20 are supplied to the calculator 23, which measures the oxygen concentration in the mixed gas. Then, the oxygen gas concentration calculated by the calculator 23 is compared with the target value by the comparator 26. If the mixed gas concentration is the same as the target value,
The operational amplifier 27 produces no output, and the flow control valve 1
7 and 19 do not change.

However, when the density value calculated by the calculator 23 is different from the target value given to the comparator 26, the comparator 26 generates an output according to the deviation. The output of the comparator 26 is amplified by the operational amplifier 27, and the linear solenoids of the flow rate adjusting valves 17 and 19 are operated to adjust the opening of the flow rate adjusting valves 17 and 19. That is, the calculator 23 calculates the concentration based on the signals from the flowmeters 18 and 20, and the control valves 17 and 19 are adjusted according to the calculated signals. Will be exactly the same as the set value.

When the flow rate adjusting valve 17 of the nitrogen gas supply pipe 11 does not exist, the supply amount of nitrogen gas cannot be set to 0 and 100%
You cannot get oxygen gas. Therefore, the flow rate adjusting valve 17 which is in the opposite operation to the flow rate adjusting valve 19 on the oxygen gas side is connected to the nitrogen gas supply pipe 11, and by completely shutting off the nitrogen gas by this flow rate adjusting valve 17, the oxygen concentration is increased.
I try to get 100% gas.

According to such a gas mixing device, since the resolution is high, it is possible to finely adjust the mixed gas concentration. That is, it is possible to maintain the accuracy with a resolution of 0.05% or less. In addition, the concentration can be lowered to the limit, which saves gas. Furthermore, since it is closed loop control, deviation from the set concentration does not occur. Moreover, since the actual flow rate is monitored by the flow meters 18 and 20 and the concentration is measured by the calculator 23, it becomes possible to record the usage state of the gas, for example, by the recorder 24 or the like. Can be easily managed.

[Effect of device]

As described above, according to the present invention, the flow rate adjusting valve and the flow meter are respectively connected to the two kinds of gas supply paths, and the detected values of the flow meters of the above two kinds of gas are input to the calculating means to thereby calculate the concentration of the mixed gas. Is calculated and the target value of the concentration is compared with the concentration calculated by the calculating means, and an output corresponding to the deviation is generated by the comparator, and the flow rates of the two kinds of gas are adjusted according to the output of the comparator. The valves are controlled by the control means so that the valves operate in opposite directions.

Therefore, the gas concentration can be controlled in a closed loop, the concentration of the mixed gas can be adjusted with high accuracy, and the deviation of the gas concentration from the target value can be prevented.

Further, the output of the comparator according to the deviation controls the flow rate adjusting valves of the two kinds of gas so that the control means performs the opposite operations to each other, so that the sum of the flow rates of the two kinds of gas is constant. It is possible to adjust the concentration.

Further, by changing the target value of the concentration preset in the comparator, it becomes possible to arbitrarily change the mixing ratio of the two kinds of gases, and thereby the concentration of the mixed gas can be arbitrarily adjusted. become.

[Brief description of drawings]

FIG. 1 is a block diagram showing a gas mixing device according to an embodiment of the present invention. The names of the main parts in the drawings are as follows. 11 …… Nitrogen gas supply pipe 12 …… Oxygen gas supply pipe 15 …… Mixed gas extraction pipe 17 …… Flow rate adjustment valve 18 …… Flowmeter 19 …… Flow rate adjustment valve 20 …… Flowmeter 23 …… Computer 26… … Comparator 27 …… Operational amplifier

Claims (1)

[Scope of utility model registration request] 1. An apparatus for mixing two types of gas to obtain a gas having a predetermined mixing ratio, wherein a flow rate adjusting valve maintained in each of the two types of gas supply paths, and supply of the two types of gas Flowmeters that are respectively maintained in the path, and the detection values of the flowmeters of the two types of gas are input, calculation means for calculating the concentration of the mixed gas, and the target value of the concentration and the calculation means Comparing with the concentration, a comparator for generating an output according to the deviation, and a control means for controlling the flow rate adjusting valves of the two types of gas so as to perform reverse operations to each other according to the output of the comparator, Gas mixing device equipped with each.