JPH09155180A - Fluid mixing device - Google Patents

Abstract

(57) [Summary] [Purpose] Automatically responds to changes and fluctuations in the flow rate used at the end, can continuously supply fluids with a predetermined mixing ratio, and keeps the pressure in the mixing channel within a certain range. A compact and simple fluid mixing device that can be controlled in a simple manner. [Structure] In a fluid mixer, in addition to a kind of constant value control obtained by controlling a flow meter, an automatic valve, a ratio setting device, and a controller installed in each fluid flow passage, a rear flow passage at a merging portion In addition, a pressure conversion mechanism, mixed fluid flow meter, and pressure adjustment valve are attached, and while controlling the mixing ratio, signals from the mixed fluid flow meter and pressure conversion mechanism automatically respond to fluctuations and changes in the used flow rate. In addition, the pressure in the mixing channel is controlled within a certain range, and the mixed fluid having a predetermined concentration is supplied.

Description

Detailed Description of the Invention

[0001]

[Industrial application] In multiple fluid mixing devices, in general industrial instruments, combinations of controllers and automatic valves, etc., do not change the controller settings one after another in order to secure the required flow rate. Automatically responds to changes in the flow rate used at the end,
A compact and simple fluid mixing device that can continuously supply fluid with a fixed mixing ratio.

[0002]

2. Description of the Related Art In a conventional mixing apparatus, the flow rate obtained by controlling with a flow meter, an automatic valve, a controller, and a ratio setting device installed in each flow path of fluid as shown in FIG. Was there. Therefore, in this conventional mixing device, it is considered to be a kind of constant flow rate control in which the ratio is adjusted. Therefore, when changing the usage flow rate at the terminal, the supply amount must be changed while maintaining the ratio control, and in this case, the setting of the controller is operated. Moreover, if the consumption flow rate changes again and again even after the resetting, it is necessary to set again each time and reset the setting according to the used flow rate each time.

[0003]

Even when the mixed fluid is used at one place, the flow rate used may be changed depending on the situation. Furthermore, when the mixed fluid is branched and used in various places, the amount of the mixed fluid to be supplied cannot always be a constant amount. Even in such a case, instead of changing the set value of the controller to change the supply flow rate one by one according to the usage amount at the terminal, the control system once set is reset even when the usage flow rate at the terminal is changed. It is intended to supply the mixed fluid with high accuracy without setting.

[0004]

[Means for Solving the Problems] In order to achieve the above purpose,
In addition to the conventional flow control system, a pressure detection mechanism was provided, and a pressure control valve that also functions as a buffer in the subsequent flow and a flow meter for measuring the flow rate of the mixed fluid were attached. Each fluid is connected to a supply source to supply the fluid. At this time, if the mixing flow rate is zero in each flow path,
The signal from the flowmeter for mixed fluid is zero, the signal sent to each controller is also zero, and the automatic valve is still closed and there is no mixed fluid in the mixing passage, so the pressure in the mixing passage is also It is zero. In this case, even if an attempt is made to flow a flow rate to the end, the pressure in the mixing channel is zero, and since there is no mixed fluid in the channel, it is impossible to permanently flow the required flow rate. Here, a pressure detection mechanism is also required to open the automatic valve first and supply the fluid. If the pressure in the flow path of the mixed fluid is less than or equal to the set value (including zero), a signal to send a constant flow rate to the controller is provided by the pressure detection mechanism and the calculation unit regardless of the flow rate used at the end. If it is set, the automatic valve will be opened even at the beginning of operation or when the pressure of the mixed fluid drops, and the flow rate until the pressure of all the space parts including the mixed fluid flow path and various equipment reaches the set pressure. Then, the flow path becomes more than the set pressure. In such a state where there is pressure in the mixed fluid flow channel, when the flow of the fluid is started by the valve of the supply destination, etc., the fluid will flow out from the mixed fluid flow channel, and the mixed fluid flow meter will output a signal of the flowing amount. It will be sent to the controller.
As a result, as soon as the circuit starts operating, its signal becomes an input to the ratio setter, and while maintaining the ratio, it is possible to adjust and supply a flow rate commensurate with the total required flow rate.

[0005]

[Operation] Even if the usage flow rate changes at the terminal, it is not necessary to change the setting value of the controller in order to flow the supply flow rate according to the usage amount. , It is possible to automatically supply a highly accurate mixed fluid.

[0006]

[Example] As a condition of this example, nitrogen and hydrogen were used as fluids. Hereinafter, the present invention will be described in detail based on the embodiments shown in FIGS. 1 and 2. As the calculation output condition of the calculation unit 8,
When the pressure in the mixing flow path 10 is out of the set pressure range, the output of the mixed fluid flow meter 4, the magnitude of the pressure of the pressure switch 5 and the calculation unit 8 output from the calculation unit 8 as follows. When the pressure is less than or equal to the lower limit: A signal with a fixed value added to the signal of the mixed fluid flow meter 4 Between the lower and upper limits: A signal of the same magnitude as the output of the mixed fluid flow meter 4 The pressure exceeds the upper limit Time: A signal obtained by subtracting a constant value from the signal of the mixed fluid flow meter 4. The mixing ratio of nitrogen gas and hydrogen depends on the setting of the ratio setter 7.

Under the above conditions, in FIG. 1, each inlet is connected to the supply gas source and the outlet is connected to the exhaust duct, and the manual valves 14 and 1 are connected.
4b is opened and gas is supplied. Pressure switch 12, 12b
Since the pressure is higher than the setting, the power of the mixing device can be turned on. Turn on the power with the manual valve 11 at the outlet of the mixing device closed, and then turn on the start switch to shut off the shutoff valves 13, 1.
Open 3b. At this time, the flow rate of the mixing flow passage 10 is zero together with the pressure, and the arithmetic circuit 8 receives the lower limit signal of the pressure switch 5, further sends the signal to the controller 3 through the ratio setter, and then to the controller 3b. The valves 2 and 2b are fully opened and the fluid starts to flow. At this time, whether the mixed fluid flow meter 4 senses the flow rate and enters the operating state with both the flow rate signal and the addition signal or operates with the added signal by the pressure switch 4 determines whether the mixing flow path 10 of this device is used. It depends on the piping capacity up to the valve 11 including the control response speed of the control system. However, since the pipe capacity is usually small and the response of the control system is fast, when the mixed gas immediately reaches the valve 11 and the pressure in the mixing passage 10 also rises instantly and exceeds the lower limit of the setting, the pressure switch 5 is reset and the mixed fluid is used. Since the signal from the flow meter 4 is zero, the signal from the calculation unit 8 to the controller 3 is also zero, and the flow rate of each flow path is adjusted to zero by the controllers 3 and 3b.

Then, when the valve 11 is opened to supply the fluid to the end, the fluid begins to flow and the mixed gas flow meter 4 naturally generates a signal corresponding to the flow rate. The signal is mixed by the calculator 8 and the pressure switch 5. The pressure position of the flow path 10 is judged, and the flow rate is started to be supplied by the amount of signal corresponding to the pressure position. If the pressure in the mixing passage 10 becomes smaller than the lower limit value of the pressure switch 5 due to some disturbance, accuracy of the flow meter, or deviation of control while the gas is being continuously supplied. The controller 8 judges this and sends a signal obtained by adding a constant signal to the signal from the mixed fluid flow meter 4 to the controller 3 to perform an operation to increase the supply flow rate by an extra amount by the increase of the signal. Eventually, when the pressure in the mixing flow path 10 is restored by the addition of the flow rate and the pressure returns to within the set value, the addition instruction by the pressure switch 5 is canceled, and the signal given from the calculation unit 8 to the controller 3 is Flow rate signal only, controller 3, 3b
Performs an adjusting operation in proportion to the mixed flow rate value.

If the pressure in the mixing channel 10 becomes larger than the upper limit set value of the pressure switch 5, the arithmetic unit 8 judges that and outputs a signal obtained by subtracting a constant value from the signal from the mixed fluid flow meter 4. The signals are sent to the controller 3, and the controllers 3 and 3b operate so as to subtract the supply flow rate by the subtraction of the signal. Eventually, when the pressure returns to within the set value due to the decrease in the supply flow rate, the subtraction command by the pressure switch 5 is canceled, and the calculation unit 8
The signal given from the controller to the controller 3 is only the flow rate signal of the mixed flow rate, and the controllers 3 and 3b perform the adjusting operation in proportion to the mixed flow rate value. This operation is repeated thereafter, but normally, the pressure in the mixing flow path portion remains within the set range, and the ratio of the output of the mixed fluid flow meter 4 to the output from the arithmetic operation portion 8 is a stable operation of 1.

When the pressure in the mixing channel is out of the set pressure range, the magnitude of the addition and subtraction signals depends on the magnitude of the flow rate change at the end and the magnitude of the disturbance.
In this case, the magnitude of the addition and subtraction signals can be arbitrarily changed by the resistance operation in the arithmetic unit.

Calculation output condition of the calculation unit 8 The lower limit 1 and 2 are provided on the pressure switch, and when the pressure exceeds the set range, the calculation unit 8 is used to set the ratio and the controller 3
When sending a constant multiple of the mixing flow rate to. The lower limit 2 which is set to the lower limit is further provided in the switch part of the pressure detection mechanism 5, and when the pressure of the mixing flow path is equal to or lower than the lower limit 2 of the pressure detection mechanism 5, a fixed amount of simulated flow rate signal is given to the controller 3. When the lower limit of the pressure detection mechanism 5 is 1 or less and the lower limit of the pressure detection mechanism 5 is 2 or more, a signal of a constant multiple of the signal of the mixed fluid flow meter 4 is given to the controller 3,
When the pressure is within the set range, the signal from the mixed fluid flow meter 4 is given directly to the controller 3. When the pressure exceeds the upper limit, a signal of less than 1 time is given to the controller 3 to give a control response. You can speed it up. However, depending on the form of selection of constants and the policy, the control circuit itself causes a kind of oscillation, and it is necessary to pay attention to the balance with the response speed considering the compressibility in the piping capacity and gas body. Therefore, whether to use the quantitative increase / decrease method or the constant multiple increase / decrease method depends on the response characteristics of the control circuit and the response characteristics brought about by the pipe capacity and the compressibility of gas. (The amount of increase and the setting of the magnification depend on the response speed of each circuit.)

In the case of FIG. 2, it is assumed that the pressure regulator is not provided immediately after the merging portion, but the automatic flow rate adjusting device and the pressure adjusting device are provided on the end use side. In this case, if there is no automatic flow rate adjusting device or pressure adjusting device on the end use side, the use place is limited to one place. If the mixed fluid is used in various ways, an automatic flow rate adjusting device or a pressure adjusting device is necessary, including a buffering meaning.

When a mixed gas flow meter for measuring volumetric flow rate is used in a gas body, the true value is obtained, although the mixed fluid flow meter 4 is controlled so as to follow unless the pressure and temperature are automatically corrected. It depends on the pressure fluctuations at the mounting positions of the flowmeters 1 and 1b. In this case, it is desirable to employ a hot-wire gas mass flow meter or a mass flow meter similar thereto as a method.

In the invention described in claim 3, when controlled by using industrial instruments, controllers, automatic valves and the like as in claims 1, 2, 3, the response delay naturally occurs. As a countermeasure for this case, the response delay due to the flow rate control was alleviated by the buffering operation using the compression of gas.

According to the invention described in claim 4, in claim 3, the buffer tank is used depending on the compression effect of the gas body, but in the liquid, the compression coefficient is small. Since this cannot be expected, a buffer tank that uses a diaphragm in a part of the tank and applies the compressibility of gas across the membrane is useful.

According to the invention described in claim 5, according to claims 1 and 2, the flow rate flowing in the same pipeline is the same regardless of the position of the pipeline measured. .

[0017]

As is clear from the above description, it is not a simple constant value, quantitative control mixed fluid supply device such as a conventional flow meter, pressure adjusting valve, controller, etc. A fluid mixing device capable of automatically responding and supplying a mixed fluid of a predetermined concentration has become possible.

[0018]

[Brief description of the drawings]

FIG. 1 is a mixing device in which a pressure detection mechanism for maintaining the pressure of mixed fluid is provided between a mixed fluid flow meter and a pressure control valve.

FIG. 2 is a mixing device in which a pressure conversion mechanism is attached to a downstream portion of the mixed fluid so as to maintain a supply pressure required at an end portion.

FIG. 3 Conventional mixing device

[Explanation of symbols]

1.1b ... Flowmeter 2.2b ... Automatic valve 3.3b Controller ... Mixed fluid flowmeter 5 ... Mixed fluid pressure conversion mechanism (pressure switch) 6 ... Pressure adjusting valve 7 ... … Ratio setter 8 ・ ・ ・ Calculator 9 ・ ・ ・ Merging section 10 ・ ・ ・ Mixing channel 11 ・ ・ ・ Manual shutoff valve 12 ・ 12b …… Pressure conversion mechanism (pressure switch) 13 ・ 13b …… Shutoff valve 14 ・ 14b …… Manual valve

Claims (5)

[Claims] 1. An apparatus for mixing a plurality of fluids at a predetermined mixing ratio and continuously supplying the mixed fluids to an end portion, the apparatus being connected to a supply source of each fluid and having a flow rate commensurate with a mixing flow rate. Installed a flow meter used for control to supply based on the output signal of the mixed fluid flow meter installed in the rear, an automatic valve, a calculation unit, a ratio setter, and a controller that can set the flow rate with an external signal. Each of the flow channels has been formed, and has a confluence portion of the flow channels for mixing the fluids, behind the confluence portion, a mixture flow meter for measuring the mixing flow rate is arranged, A pressure regulating valve is arranged in the downstream of the flowmeter for the mixture, and a pressure detection mechanism is provided between the flowmeter for the mixture and the pressure regulating valve in order to maintain the input pressure necessary for the function of the pressure regulating valve. , And the signal of the pressure detection mechanism is output as an input of the arithmetic unit as upper and lower limit pressure switches, The calculation unit that receives the signals from the combined flowmeter and pressure switch outputs the signal with the calculation result as the input to the controller, and the controller outputs the signal when the supply flow rate or the pressure is excessive or insufficient, or at the end. A device that follows the change when the flow rate is changed and supplies the fluid at a specified mixing ratio and controls the pressure in the mixing flow path part within a certain range. 2. A device for mixing a plurality of fluids at a predetermined mixing ratio and continuously supplying the mixed fluids to the end portion, which is connected to a supply source of each fluid and has a flow rate commensurate with the mixing flow rate. Installed a flow meter used for control to supply based on the output signal of the mixed fluid flow meter installed in the rear, an automatic valve, a calculation unit, a ratio setter, and a controller that can set the flow rate with an external signal. Each of the flow paths has a flow path and has a confluence part of the flow paths for mixing the fluids, and a mixture flow meter for measuring the mixing flow rate is arranged behind the confluence part, and the mixing is performed. In order to maintain the required supply pressure in the wake of the body flow meter, a pressure detection mechanism is arranged, and the signal of the pressure detection mechanism is output as an input of the calculation unit as a pressure switch of the upper and lower limits, and for the mixture The calculation unit that receives signals from the flowmeter and pressure switch inputs the calculation results to the controller Is to, it outputs a signal that controllers,
When there is an excess or deficiency in the supply flow rate and pressure due to the above signal or when the flow rate at the end is changed, the change is followed and the fluid is supplied at a specified mixing ratio and the pressure in the mixing flow path part is controlled within a certain range. Device to do. 3. A buffer storage tank immediately after the joining part, which is sufficient to compensate for the response delay of the control of the flow meter, the automatic valve, and the controller, which occurs during the correction operation for the correction due to the fluctuation of the flow rate at the end. The fluid mixing device according to claim 1 or 2, wherein the fluid mixing device is arranged in the. 4. The buffer tank according to claim 3, wherein the buffer tank is a diaphragm type or has a buffer device that can be expected to be effective to the same degree. For the liquid tank, the buffer tank according to claim 1, 2, or 3. A fluid mixing device as described. 5. The mixing device, wherein a flow meter for measuring a mixed fluid is installed behind a pressure regulating valve in a mixing flow path section,
The fluid mixing device according to claim 1, 3, or 4.