JPS62109106A - Flow rate controller - Google Patents

Abstract

PURPOSE:To control the total flow rate value within a proper range by totalizing the flow rate values of each filter device controlled so that the even flow rate passes for calculation of the total flow rate value and controlling this total value toward the set constant value. CONSTITUTION:A total flow rate computing element 16 adds the flow rate values shown by the flow rate signals S5a-S5c in response to these signals given from the flow rate detectors 4a-4c for calculation of the total flow rate value and delivers the total flow rate signal St showing the result of said calculation. An additional 2nd controller 12 keeps the balance between the signal St and the total flow rate set value signal S15 showing the total flow rate value set previously and then supplies the operating output signals all at once to the 1st controllers 6a-6c in the form of the even flow rate designating signal S14. Thus the control valves 7a-7c of separation paths 2a-2c are controlled so that the total flow rate value of the fluids to be processed which are evenly allocated and pass through those paths 2a-2c are equal to the set total flow rate value.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a flow rate control device that controls the flow rate of a fluid to be processed through a filtration device at a fixed value, and in particular, the present invention relates to a flow rate control device that controls the flow rate of a fluid to be processed through a filtration device at a fixed value, and particularly to The present invention relates to an improvement in a control system that controls the total value of each of the equal flow rates to a constant value in a device through which a fluid to be treated passes.

<Prior art> In filtration processing equipment, especially those that perform precoat processing, when multiple equipment is operated in parallel to handle large flow rates, the flow rate passing through each equipment is different. If this occurs, the equipment with a high flow rate will be subject to concentrated accumulation of contaminants, and the usable life of the filter material in that equipment will be extremely shortened, resulting in the need to replace the filter material for the entire equipment. This has the disadvantage that the work increases.

In order to eliminate this inconvenience, it is necessary to equalize the flow rate of the fluid to be treated that passes through multiple filtration devices operated in parallel, and to equally distribute the burden of filtration processing in each device. However, as a result, the usable period of the filter medium used in the device is extended as a whole.

The configuration of the conventional device with such fluid equalization is the second
As shown in the figure.

The main inflow channel 1 is divided into three branch channels 2a, 2b, and 2c.

Filtration processing devices 3a, 3b, and 3c precoated with a filter material are inserted into each of them.

Branch flow path 2a on the outlet side of each filtration processing device 3a, 3b, 3c
, 2b and 2c each have three flow rate detectors 4d.
, 4b, 4c are provided, and each flow rate detector has a
Wenzhou signal lines 5a, 5b, and 5c extend to process signal terminals of three direct-acting controllers 6a, 8b, and Be (hereinafter referred to as first controllers), respectively. moreover,
The branch channels 2a, 2b, 2c are connected to the flow rate detectors 4a, 4.
Control valves 7a, 7b, and 7c are provided subsequent to the control valves b and 4c, and the control valves are connected to the first controller 6.
Valve operation signal lines 8a, 8b, and 8c extend from the operation output signal terminals a, eb, and 6c, respectively. The valve operation signal lines 6a, 6b, and 8c are respectively connected to each input terminal of a signal comparator 9, and the comparator is followed by a signal inverter 10, and from the output terminal of the inverter, , a maximum valve opening signal line 11 extends to a process signal terminal of a reverse-acting controller 12 (hereinafter referred to as a second controller).

On the other hand, the operation output signal terminal of the second controller 12 is connected to the
Equal flow rate designation signal lines 14a, 14b,
14C1, and the set value signal terminal of the controller 12 is connected to the maximum valve opening set value signal line 13.
It is connected to a voltage setting device (not shown), such as a digital voltage setting device, through the terminal.

The branch channels 2a, 2b, and 2c are combined into a main outlet channel 15 behind each of the control valves 7a, 7b, and 7c provided therein. Note that in the above configuration example, the control valves 7a,
As 7b and 7c, the valve opening degree is driven to decrease in response to the increasing tendency of the valve operation signal.

In a conventional device such as a "bipod", the fluid to be treated is pumped into the main inflow channel 1 by a water supply pump (not shown), and is sent to the filtration processing device 3a, through the branch channels 2a, 2b, and 2c. 3b, 3c to remove contaminants in the fluid to be treated, the treated fluid passes through flow rate detectors 4a, 4b, 4c and control valves 7a, 7b, 7c, respectively. Although it flows out from the main outflow path 15,
At this time, to explain one branch flow path 2a, a flow rate signal S5a representing the flow rate of the processed fluid passing through the flow rate detection rji4a is sent to the first controller 6a.
This signal S5a is input as a process signal to
In response to this, the first controller 6a increases or decreases in proportion to the difference between the signal S5a and the equal flow rate designation signal 514, which will be described later, which is supplied to its set value signal terminal, and when the difference is eliminated. A valve operation signal S8a that remains at the value at is output from the operation output signal terminal. In response to this signal S8a, control valve 7a maintains the valve opening indicated by signal S8a and controls the flow rate of fluid passing therethrough.

Therefore, if for some reason the flow Ul of the branch channel 2a
S shows a decreasing tendency, and the flow rate signal S from the flow rate detector 4a
5a also shows a decreasing tendency, if the equal flow rate designation signal S14 supplied to the set value signal terminal of the first controller 6d is fixed and considered, the signal t'fs14 (set value signal ), the flow rate signal 55a (process signal) decreases, so the valve operation signal S8a decreases, and the control valve 7d receiving this decreases its valve opening degree. Such a decreasing tendency of the valve operation signal S8a prompts an increase in the valve opening degree of the control valve 7a and increases the flow rate of the branch flow path 2a, whereby the flow rate signal S5a is fixed at this stage of the explanation. The above flow rate increase trend continues until equilibrium is reached with respect to the equal flow rate signal 514, and the valve operation signal S at the equilibrium point
The control valve 7a is controlled to the valve opening degree corresponding to 8a. Thus, by the control action of the first controllers 8a, 6b, and 6c, the flow rates of the branch channels 2a, 2b, and 2C are the only flow rates designated by the common equal flow rate designation signal 514 of each first controller. Since the fixed price is controlled toward the target price, the flow rates in the branch channels 2a, 2b, and 2C are always equal.

Further, assuming that the filtration processing device 3a is more contaminated than the other filtration processing devices 3b and 3c, the differential pressure in the filtration processing device 3a is higher than that of the other filtration processing devices 3b and 3c.
Therefore, the flow rate of the branch channel 2a tends to be the smallest among the branch channels.

However, since the flow rates in each of the branch channels 2d, 2b, and 2C become equal to each other due to the above-mentioned constant (1"l i'l) control, since such flow rates pass through the branch channel 2a, In this case, the valve opening degree of the control valve f7a is controlled to be larger than that of the other control valves 7b and 7C.The valve opening degree of the control valve 7a controlled in this way is substantially The indicated valve operation signal S8a is further supplied to a signal comparator 9, and this signal comparator 9 is supplied with flow rate signals arranged in the same manner as described above for the branch channels 2b and 2c behind the filtration processing devices 3b and 3C, respectively. Valve operation signal S8b from the first controllers 6b, 6c in a configuration including detectors 4b, 4c, first controllers 8b, 8c, and control valves 7b, 7c
, S 8c are also supplied, and among these valve operation signals S 8a, S 8b, and S 8c, the one with the smallest value is compared and selected and outputted from there. By the way, in this embodiment, since the minimum valve operation signal represents the maximum valve opening degree, the signal comparator 9 detects the maximum valve opening degree among the control valves 7a, 7b, and 7c according to the above operation description. The valve operation signal S8a supplied to the valve opening having the valve opening degree is compared and selected.

The direction of change of the output signal from the comparator 9 is reversed by the subsequent signal inverter IO, and the maximum valve opening signal S
ll is supplied to the process signal terminal of the second controller 12.

Then, the second controller 12 increases or decreases in inverse proportion to the difference between the maximum valve opening setting value signal 313 and the former maximum valve opening signal 311 supplied to the setting value signal terminal, and the difference increases or decreases. The equal flow rate designation signal S14, which remains at the value at the time of cancellation, is simultaneously supplied to the set value signal terminals of each of the first controllers 6a, 6b, and 6c. That is, in the second controller 12, the valve opening of the control valve 7a, which is represented by the maximum valve opening signal Sll, is represented by the maximum valve opening setting value signal 313, which is manually set by a voltage setting device (not shown). The change in the equal flow rate designation signal S14 continues until the valve opening is balanced with respect to the valve opening.

Then, in this way, the flow rate of each distribution path 2a, 2b, 2c is controlled by additional value toward the new flow rate target value specified by the changed uniform flow rate designation signal Sf4. Each first controller 6a, 6b, 6c is activated.

In this way, the flow rate of the fluid to be treated that equally passes through the filtration processing devices 3a, 3b, and 3c is determined by the valve opening degree of the control valve that controls Ii of the filtration processing device whose differential pressure is the largest. Maximum valve opening setting value signal S13 to controller 12 of No. 2
Under the condition that the valve opening is equal to the value set by
This value is determined as the flow rate value passing through the control valve with the maximum valve opening.

<Problems to be Solved by the Invention> However, in such conventional devices, the flow of the fluid to be treated that passes through the filtration devices inserted in each branch channel is always equalized, and the flow of the fluid in each filtration device is Although the burden of filtration processing is distributed evenly, the valve opening of the control valve with the largest valve opening among the control valves installed in each branch channel is controlled to a fixed value toward the set value. Therefore, the flow rate value of the fluid passing through the control valve with the largest valve opening, in other words, the absolute value of the flow rate of the fluid to be treated passing through each filtration treatment device, and in other words, Regarding the overall evaluation of the flow rate of the treated fluid passing through each filtration treatment device,
The value varies depending on the status of the supply system such as the water pump that pumps the water into the main inflow channel, the structure of the S filtration device, the degree of contamination of the filter material, and other load conditions. However, the absolute value of the flow rate itself could not be controlled at all.Furthermore, filtration processing equipment, especially those that have been subjected to pre-coating processing, have relatively strict restrictions on the flow rate that passes through them. Proper use Iif, N
Since the radius R is quite limited, it cannot be controlled at all by the conventional device described above, so an excessive or insufficient flow rate of the fluid to be treated passes through the filtration treatment device. This was often the case. As a result, if too much flow is allowed to pass through, contaminants may leak from the filtration equipment, while if too little flow is allowed to pass, processing time becomes longer and work efficiency is reduced. There was a problem with the decline.

Furthermore, the lf of the fluid to be treated passing through each filtration treatment device
The fact that the absolute values of T and ff are not controlled means that the total flow rate value, which is the sum of them, is also not controlled, so the total flow value often increases to an excessive value. As a result, there was a problem that cavitation was caused in the water pump.

Means for Solving the Problems This invention solves the problems of leakage of contaminants and reduction in work efficiency caused by inappropriate flow values in each filtration processing device based on the above-mentioned conventional technology, and furthermore, solves the problems of each filtration processing device. In view of the problem of cavitation in water supply pumps caused by an increase in the total flow rate of each processing bag, each filtration device is controlled so that an equal flow rate passes through each filtration device operated in parallel. By summing the flow values at and calculating the total flow value, and controlling the total flow rate toward the total Iiii set value,
The flow rate value of the fluid to be treated in each filtration treatment device, and by extension, their total value, is controlled within an appropriate range, thereby preventing leakage of contaminants from the filtration treatment device, low work efficiency, and furthermore, water pump This problem is solved by completely preventing the occurrence of cavidion.

As shown in FIG. 1, the structure of the present invention is such that the flow rate of the fluid to be treated in each of the filtration devices 3a, 3b, 3c that are operated in parallel in a plurality of branch channels 2a, 2b, 2c is When equalizing the flow rate, an equal flow rate designation signal S14 is simultaneously supplied to the first controllers Eia, 6b, and 8c for each of the control valves 7a, 7b, and 7c, and in response,
These controllers 8a, 6b, and 6c each receive a common equal flow rate designation signal 514 (set value signal) and a flow rate signal S from the flow rate detectors 4c, 4b, and 4c in each branch flow path.
5a, S5b, and 55c (process signals), and control the valve opening degree of each control valve using the output signals S8a, S8b, and 58c (manipulation output signals), so that the fluids to be treated can have equal flow rates. In the control system in which the flow rate passes through each filtration processing device, the total flow rate calculator 16 attached thereto responds to each flow rate signal S5a, S5b, S5c from each flow rate detector 4a, 4b, 4c, The flow rate values represented by these signals are added to calculate the total flow rate value, and a total flow rate signal St representing the calculation result is output, and the attached second controller 12
This total flow rate signal St (process signal) is balanced with a total flow rate set value signal 515 (set value signal) representing a preset total flow rate set value, and the manipulated output signal is converted into an equal flow rate designation signal 514 (set value signal). It acts to supply the first controllers 6a, 8b, 6c all at once as a value signal), and as a result, it is evenly distributed and sent to each branch channel 2a, 6c.
The total flow rate value of the treated fluid passing through 2b and 2c is
Each branch flow path 2a, so that the set total flow rate setting value is achieved.
The control valves 7a, 7b, 7c in 2b, 2c are controlled.

<Example> An example of the present invention will be described below based on FIG.

From each flow rate detector 4a, 4b, 4c to each first controller 8a.

The flow rate signal lines 5a, 5b, 5c extending to each process signal terminal 6b, 6c are each branched into one branch in the middle and connected to each input signal terminal of a total flow rate computing unit 16, and the output signal of the computing unit 16 is connected to each input signal terminal. The terminal extends to a process signal terminal of the second controller 12.

The setting signal terminal of the second controller 12 is connected to the output terminal of the total flow rate setting device 17, which is composed of a potentiometer or the like and outputs a total flow rate set value signal S15 representing the total flow rate set value according to the setting operation, Furthermore, the controller 12
The operation output signal terminals of the controllers are commonly connected to each set value signal terminal of each of the first controllers 8a, 8b, and 8c through a total flow signal line 11. The other components are the same as those indicated by the same reference numerals in FIG.

In such a configuration, assuming that the uniform flow rate designation signal S14, which is the operation output signal from the second controller 12, is fixed, each of the first controllers 8a, 6b.

Regarding 6c, based on FIG. Flow rate signals S5a from the devices 4a, 4b, 4c,
List price control for balancing s5b, s5c (process signals) is performed separately by the first controllers 6a, 6b, 6c, and as a result, each branch flow path 2a, 2b
, 2c, the flow rate of the fluid to be treated is equal to the uniform flow rate designation signal 5
Ii, expressed as 14, is equalized as %.Now, if we supply the total flow signal St from the total flow calculator 16 to the set value signal terminal of the second controller 12, we will consider: First, the total flow rate calculator 16 has its input terminals supplied with flow rate signals S5a, S5b, S5c from the respective flow rate detectors 4a, 4b, 4c,
The flow values represented by these signals are added here to obtain a total flow signal St representing the total flow value as a result of the addition.Next, this total flow signal St is received as a process signal. second controller 1
2 performs fixed value control so that the total flow rate signal St matches the total flow rate set value signal S15 supplied as a set value signal from the total flow rate setting device 17, and the equalization signal that is the operation output signal at that time Each of the first controllers 8a, 6b, 6 described above uses the flow rate designation signal S14 as a set value signal.
Supply all at once to c.

For example, for some reason, the total flow rate calculator 16
When the total flow rate signal St increases and becomes larger than the preset total flow rate set value signal 515,
In the second controller 12 to which these signals are supplied,
Since the process signal becomes larger than the set value signal, the second controller 12 of the reverse operation type decreases the equal flow rate designation signal S14, which is its operation output signal, in response.

Then, each of the first controllers 6a, 8b, 8c corresponds to each flow rate detector 4a, 4b.

4C to balance the flow signals S5a, S5b, S5c against the aforementioned reduced common equal flow designation signal S14, i.e. each control valve 7a, 7b, 7
It operates to reduce the opening degree of the valve c, and each branch flow path 2a, 2
b, reducing the flow rate of the fluid to be treated passing through the filtration devices 3a, 3b, 3c in 2c;

This flow rate decreasing tendency is detected by the flow rate detector 4a.

Flow signals S5a, S5b, S5 from 4b, 4c
c, and as a result, the total flow rate signal St from the total flow rate calculator 16 decreases, and the decreasing tendency of the Ii amount continues until this total flow rate signal St is balanced with the total flow rate set value signal 515.

Furthermore, for some reason, the total li and the clear signal St are
Contrary to the above explanation, if this decreases and becomes smaller than the total flow set value signal S15, the second controller 12
increases the equal flow rate designation signal 314, and in response to this, each of the first controllers Ga, 6b, 8c increases the flow rate of the fluid to be treated in each of the branch channels 2a, 2b, 2c. Each control valve? Valve opening 1 for a, 7b, 7c
It operates to raise i.

Each of the first 34m meters 8a, 8b, and 6c is an operation output signal that changes from time to time to control the planting of the total flow rate signal St toward the total flow rate set value signal S15 at the second controller 12. For the common uniform flow rate designation signal S14, each flow rate detector 4a, 4b, 4c
Each from? In order to separately control the m signals S5a, S5b, and S5c, each branch flow path 2a, 2b, 2c is used.
The valve opening degree of each of the control valves 4a, 4b, 4c is adjusted to the total flow rate setting value for each filtration processing device 3a, 3b, 3c for each branch channel 2a, 2b, 2c. The fluid to be treated is passed through the flow rate value obtained by equally dividing the equal total flow rate value into the number of branch channels.

Effect> As described above, according to the present invention, the flow rate signal from each flow rate detector in each branch flow path is guided to the total flow rate calculator, where the total flow rate value is calculated, and the total value representing this value is calculated. An operation in which the flow rate signal is supplied as a process signal to a second controller, and the second controller outputs the total meteor signal to control the total flow rate set value signal with respect to a preset total flow set value signal. The equal flow rate designation signal, which is an output signal, is sent to each first controller of each flow rate detector in each branch channel to a set value,
In order to control each flow rate signal from each flow rate detector at the same time with respect to a common uniform flow rate designation signal, this first controller controls the valves of the control valves for each branch flow path. By adopting a configuration that adjusts the opening degree, the filtration processing device in each branch channel is uniformly filled with the fluid to be treated at each flow rate such that the total flow ja value matches the preset total flow rate setting value. Since the absolute flow rate of the fluid passing through each filtration device can be kept within the appropriate flow rate range, leakage of contaminants due to excessive flow rate can be prevented. Not only can you completely prevent a decrease in work efficiency caused by low flow rates or insufficient flow rates, but you can also control the total flow rate of the treated fluid that passes through multiple filtration devices to an appropriate value, so you can avoid excessive total flow rates. This provides an excellent effect of reliably preventing the occurrence of gearing of the water supply pump due to this.

Furthermore, by summing each flow rate value represented by the flow rate signal from each flow rate detector for each branch flow path using a total flow rate calculator to calculate the total flow rate value, the total flow rate can be calculated directly. Since there is no need to measure the flow rate, it is possible to avoid installing a flow meter for large flow rates, and there is also the advantage that the cost can be reduced accordingly.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a circuit diagram showing a conventional device. 1... as inflow channels 22a, 22b, 22c,... branch channels 3a, 3b, 3
C1...Overtreatment device 4a, 4b, 4c,...Wenzhou detection path 6a, 6b, 6c,...First controller 7a, 7b, 7
c, . . . control valve 12 . . . second, il! 1-section meter 15...Main outlet path 16...Total flow rate calculator 17...Total flow rate setting value S5a, S5b, S5c,...Flow rate signal S
t...Total flow rate signal

Claims (1)

[Scope of Claims] A plurality of filtration processing devices 3a, 3b, 3c inserted in a plurality of branch channels 2a, 2b, 2c through which the fluid to be treated passes, and provided in each branch channel 2a, 2b, 2c, The flow rate of the fluid passing through each branch channel is measured, and the measurement result is sent to the flow rate signal S5.
Flow rate detectors 4a, 4b, and 4c that output output flow rate detectors 4a, 4b, and 4c are provided as a, S5b, and S5c, respectively, and the valves are provided in each of the branch channels 2a, 2b, and 2c, and respond to each valve operation signal S8a, S8b, and S8c. A control valve 7 that increases/decreases the opening degree and controls the flow rate of fluid passing through each branch channel.
a, 7b, 7c, and a valve operation signal S8a as an operation output signal by balancing the flow rate signals S5a, S5b, S5c as process signals with the equal flow rate designation signal S14 as a set value signal,
In a flow rate control device having a first controller 6a, 6b, 6c that supplies S8b, S8c to each control valve 7a, 7b, 7c, a flow rate signal S5a from each flow rate detector 4a, 4b, 4c,
A total flow rate calculator 16 that calculates a total flow value by summing each flow rate value represented by S5b and S5c, and outputs the calculation result as a total flow rate signal St; The total flow rate signal St as a process signal is balanced against the flow rate set value signal S15, and the equal flow rate designation signal S14 as an operation output signal is used as a set value signal for each of the first controllers 6a, 6b, and 6c. A flow rate control device that is equipped with a second controller 12 that supplies all at once.