JPH0527851A - Control method for relation between flow rate and pressure - Google Patents

Abstract

PURPOSE:To provide the control method for relation between the flow rate and the pressure for automatically controlling both the flow rate and the pressure. CONSTITUTION:A flow rate instruction controller 4, a pressure instruction controller 6, a flow rate control valve 5, and a pressure control valve 7 are provided in a fluid path of a fluid processor 3. Then the target value is compared with the present value is regard of both the flow rate and the pressure. Based on the result of comparison, the relevant control valve is actuated in an opening amount set previously. Then the valve actuated in an opening amount set previously. Then the valve opening/closing direction is reversed every time the result of comparison is reversed. Furthermore the valve opening amount is reduced down to the half of the unreversed value in geometrical progression and approximated to the target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device which requires both flow rate and pressure control, such as a food liquid (eg beer) which requires pressure control at the same time as flow rate control in order to prevent foaming or bumping in the liquid. In a sterilization manufacturing apparatus, the present invention relates to a method for controlling the other of the flow rate and the pressure to be constant even if one of them changes.

[0002]

2. Description of the Related Art In the above sterilization manufacturing apparatus, it is necessary to keep pressure and other conditions constant even if the flow rate changes. However, if the flow rate is changed, the pressure changes without permission. Therefore, while watching the pressure gauge and the flow meter, the valves at the inlet and the outlet of the heat exchanger were manually and repeatedly adjusted.

[0003]

However, the conventional method of manually operating the inlet and outlet valves of the heat exchanger has poor workability and is very troublesome. Note that automatic control for adjusting only one of the flow rate and the pressure to a set value is generally performed, and there are many control devices. However, in the conventional automatic control system, if the flow rate is changed, the pressure also changes, so
It was difficult to automatically control both the flow rate and the pressure.

The present invention has been proposed in view of the above problems of the prior art, and an object of the present invention is to make it possible to automatically control the other constant even if one of the flow rate and the pressure changes. Another object of the present invention is to provide a related control method of flow rate and pressure.

[0005]

In order to achieve the above object, the present invention provides a flow rate indicating controller and a pressure indicating controller in a fluid path of a fluid processing apparatus which requires control of both flow rate and pressure. A control valve and a pressure control valve are provided, and for the flow rate and pressure, the respective instruction controllers are used to compare the current value with the target value, and the control valve is activated according to the preset opening and closing degree according to the result. When the magnitude relationship is reversed during the process, the opening / closing direction of the control valve is reversed, and the opening / closing degree of the control valve is controlled to be 1/2 of the opening / closing degree immediately before the magnitude relationship is reversed. Is.

[0006]

Function: Even if one of the flow rate and the pressure changes, the other is automatically controlled to be constant as follows. That is, every time the magnitude relationship between the target value and the current value reverses, the valve opening is set to 1
/ 2, the valve opening and closing direction is reduced in a geometric progression, and the valve opening and closing direction is reversed, so that the target value can be reached within a short time. ..

[0007]

1 is a schematic configuration diagram of the entire apparatus showing a first embodiment of the present invention, in which (1) is a supply tank for a liquid to be treated, (2) is a supply pump, and (3) is heat. A fluid processing device such as an exchanger, (4) a flow rate control controller, (5) a flow rate control valve, (6) a pressure control controller, (7) a pressure control valve,
(8) shows bypass piping.

The supply tank (1) for the fluid to be processed contains the fluid to be processed such as food liquid.

The flow path of the processing liquid to the fluid processing device (3) such as a heat exchanger is not shown.

A spiral pump or the like is used as the supply pump (2) and is connected by piping so as to supply the processed fluid from the processed fluid supply tank (1) to the fluid processing apparatus (3).

The fluid treatment device (3) is a device for heating, cooling, sterilizing, or otherwise treating the fluid to be treated, and for example, even if either the flow rate or the pressure of the fluid to be treated changes. It is suitable for use in an apparatus that requires constant control of the other.

The flow rate instruction controller (4) is installed in the fluid pipe path on the inlet side of the fluid treatment device (3), and controls the flow rate of the fluid to be treated supplied from the supply pump (2) to the fluid treatment device (3). The function of setting and instructing the flow rate as the target value is detected and displayed, the detected value is compared with the target value, and the flow rate control valve (5) is operated according to the preset opening and closing degree according to the result, When the magnitude relationship reverses, the opening / closing direction of the flow rate control valve (5) is reversed, and the opening / closing degree at that time is controlled to be 1/2 of the opening / closing degree immediately before the magnitude relationship reverses. A device having a function of iteratively controlling within the tolerance of the target value is used.

As the flow rate control valve (5), a diaphragm valve or the like is used which is capable of continuously adjusting the valve opening degree in the range of 0 to 100 (%) according to a command from the flow rate instruction controller (4). The flow rate control valve (5) is connected to the fluid treatment device (3).
It is installed in a bypass pipe (8) branched from the middle of the fluid pipe path on the inlet side of the. Bypass piping (8)
This is for returning a part of the fluid to be processed supplied from the supply pump (2) to the supply tank (1). By adjusting the return amount by the flow rate control valve (5), the fluid processing device ( It controls the amount supplied to 3).

The pressure instruction controller (6) is installed in the fluid piping path on the outlet side of the fluid treatment device (3) and gives an instruction to set the pressure of the fluid to be treated passing through the fluid treatment device (3) as a target value. Function and the current value of pressure are detected and displayed, and the detected value is compared with the target value. Depending on the result, the pressure control valve (7) is operated at preset opening and closing degrees, and if the magnitude relationship reverses during the operation. , The pressure control valve (7) is opened and closed in the reverse direction, and the opening and closing degree at that time is controlled to be 1/2 of the opening and closing degree immediately before the reverse of the magnitude relationship, and this is repeated to set the target value. What has a function to control within the allowable value of is used.

As the pressure control valve (7), a diaphragm valve or the like is used which is capable of continuously adjusting the valve opening degree in the range of 0 to 100 (%) according to an instruction from the pressure instruction controller (6). The pressure control valve (7) is set in the middle of the fluid piping path on the outlet side of the fluid treatment device (3) and downstream of the installation position of the pressure instruction controller (6).

The first embodiment of the present invention is constructed as described above, and its operation will be described below.

Now, set the flow rate and pressure to target values, respectively.
Open and close once for each control valve (5) (7)
Also set. And, for example, if you change the flow rate
The automatic control so that the pressure remains constant.
This will be described with reference to FIG. In this case, the target value is P₀And the current value is
P₁, Then compare these, P₁If is large
The pressure control valve (7) is opened, and if it is small, it is closed.
This operation amount is set to a preset opening / closing degree (for example, 5%).
It In the case of FIG. 2, P₁Is a large pressure control valve
Open (7) by the preset opening / closing degree (5% in the above example).
To operate. The pressure after this opening operation is P₂Was
And this P₂And P₀To compare. And P₂Is P₀Than
Since it is large, the pressure control valve (7) has a preset opening / closing degree.
(5% in the above example) is further opened. This second time
Pressure after opening is P₃And this P₃Is P₀Than
If it is still large, open the third time under the same conditions as above.
Let the work be done. However, in the case of FIG.₃Is P₀Less than
Therefore, the magnitude relationship is reversed and the so-called target value is exceeded.
It's a burran. When this happens, this time
Reverse the opening / closing direction of the pressure control valve (7) to close it.
I will However, the degree of opening and closing during the closing operation in this case is reversed.
Half of the previous opening and closing degree. The pressure after this closing operation is P_Four
And this P_FourAnd P₀Compare the size relationship with
Of P_FourIs P₀If it is within the allowable value of, the adjusting operation ends.
But P^FourIs P⁰Is not within the allowable value of ₀Bigger than
If so, compared to the last time, the magnitude relationship has reversed again.
It Therefore, this time, the pressure is further reduced by 1/2 of the previous opening / closing degree.
The force control valve (7) is opened. In this way, the goal
Whenever the magnitude relationship between the current value and the value reverses, the valve opening
Controlling to 1/2 of valve opening before reverse rotation and adjusting width by 1/2
By decreasing it, you can keep it within the tolerance of the target value.
It is designed to be as close as possible in a short time. The figure
In the example of 2, P_FourIs P₀Smaller than the target value
Sometimes it is not within the allowable value of₃Or
Et al P_FourValve opening at the time of the first reverse rotation to
/ 2) close the pressure control valve (7) with the same valve opening
It is a thing.

In the above description of the operation, the case where the pressure is automatically controlled to be constant with respect to the change of the flow rate has been described. Conversely, the operation of automatically controlling the flow rate to be constant with respect to the change of the pressure is exactly the same.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the bypass pipe (8) is omitted, and the flow control valve (5) is installed in the fluid pipe path on the inlet side of the fluid treatment device (3).
Is similar to that of the first embodiment, and its operation is also similar to that of the first embodiment.

[0020]

According to the present invention, it is possible to control both the flow rate and the pressure automatically and in a short time for a fluid processing apparatus that requires control of both the flow rate and the pressure, thus improving workability. To do.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an entire apparatus showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of control of pressure and valve opening according to the present invention.

FIG. 3 is a schematic configuration diagram of an entire apparatus showing a second embodiment of the present invention.

[Explanation of symbols]

 1 Supply Tank 2 Supply Pump 3 Fluid Processing Device 4 Flow Rate Control Controller 5 Flow Control Valve 6 Pressure Control Controller 7 Pressure Control Valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location G05D 16/20 D 7314-3H (72) Inventor Teruhisa Kiyose 3-848 Morofuku, Daito City, Osaka Prefecture No. (72) Inventor Masayuki Harada 536-30 Minamikasa-cho, Kusatsu City, Shiga Prefecture (72) Inventor ▲ Maki ▼ Kaoru 1-10-14 Awaza, Nishi-ku, Osaka City, Osaka Prefecture Sanko Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A flow rate indicating controller and a pressure indicating controller, a flow rate adjusting valve and a pressure adjusting valve are provided in a fluid path of a fluid processing apparatus that requires control of both flow rate and pressure. Regarding the flow rate and pressure, each instruction controller compares the magnitude of the current value with each of the target values, and depending on the result, the corresponding control valve is operated for each preset opening / closing degree, and if the magnitude relationship reverses midway. , Reverse the opening / closing direction of the corresponding control valve, and control the opening / closing degree of the corresponding control valve to be 1/2 of the opening / closing degree immediately before the reversal of the magnitude relationship, and repeat this to allow the target value. A related control method of flow rate and pressure characterized by controlling within a value.