TW201508432A - Rinsing fluid flow control system and control method thereof - Google Patents

Abstract

The present invention discloses a rinsing fluid flow control system. The system comprises a main line and a plurality of branches. In one embodiment, the main line is provided with a control valve, a pressure sensor, a controller and an I/P converter. The rinsing fluid flows through the control valve. The pressure sensor measures pressure of the rinsing fluid flowing through the control valve and outputs a pressure value. The controller receives the pressure value outputted by the pressure sensor and compares the pressure value with a target pressure value. A current signal is generated and sent according to a comparison result. The I/P converter receives the current signal outputted by the controller and delivers compressed air having correspondingly pressure to the control valve so that the pressure value of the rinsing fluid flowing through the control valve measured by the pressure sensor equals to the target pressure value. Each branch is provided with a flow switch for measuring a flow rate of the rinsing fluid and a pin valve for regulating the flow rate of the rinsing fluid. By means of regulating the pin valve of each branch, the flow rate of the rinsing fluid of each branch can equal to a target flow rate. The present invention further discloses a rinsing fluid flow control method.

Description

Cleaning liquid flow control system and control method

The invention relates to a semiconductor device manufacturing process, in particular to a cleaning liquid flow control system and a control method, which can accurately and stably control the flow rate of the cleaning liquid.

In the semiconductor device manufacturing process, the wafer is easily contaminated, and micro-contaminants such as particles attached to the surface of the wafer, organic residues, metal impurities, and wafer surface oxides can cause great damage to the performance of the semiconductor device. And as the feature size of semiconductor devices becomes smaller and smaller, the harmfulness of pollutants will become larger and larger, and almost every step of the process may introduce pollution. Therefore, in order to obtain high quality semiconductor devices, cleaning wafers is very necessary and critical. With the rapid development of semiconductor technology, at present, there are various cleaning methods, among which, wet cleaning is a cleaning method widely used in wafer surface cleaning processes. Wet cleaning typically uses cleaning fluids such as ultrapure water or chemicals of different compositions to clean the wafer surface. The cleaning fluid is typically supplied to a cleaning chamber where the wafer is cleaned.

In order to ensure the cleaning effect and improve the quality of the semiconductor device, the flow rate of the cleaning liquid supplied to the cleaning chamber needs to be accurately and stably controlled, that is, the cleaning liquid maintains a stable flow rate during transportation. Conventional cleaning fluid flow control systems include several control valves. In general, Each of the cleaning fluid delivery channels connected to the cleaning chamber has a control valve that controls the flow of cleaning fluid within the channels. Although the system can accurately and stably control the flow rate of the cleaning liquid in each channel, when there are several cleaning liquid delivery channels, a corresponding number of control valves are required. Since the control valve is expensive, the entire system is produced. The cost is high, and at the same time, the size of the control valve is large, which requires a large space, which is inconvenient for the design and installation of the entire system.

Therefore, simplifying system design and reducing system cost will be a breakthrough in the field of semiconductor cleaning technology under the premise of ensuring stable and controllable cleaning fluid supply.

It is an object of the present invention to provide a cleaning fluid flow control system that is low in cost and simple in construction.

In order to achieve the above object, a cleaning fluid flow control system provided by the present invention comprises a main trunk road and a plurality of branches, wherein the main trunk road is provided with a control valve, a pressure sensor, a controller and an I/P converter, each A flow switch and a needle valve are provided on one road. The cleaning fluid flows through the control valve; the pressure sensor measures the pressure of the cleaning fluid flowing through the control valve and outputs the pressure value; the controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, according to the comparison As a result, a current signal is generated and transmitted. If the pressure value is greater than the target pressure value, the controller sends a smaller current signal. If the pressure value is less than the target pressure value, the controller sends a larger current signal; the I/P converter Receiving a current signal output by the controller and delivering compressed air having a corresponding pressure to the control valve, the I/P converter receiving a smaller power output from the controller When the signal is flowing, the I/P converter reduces the pressure of the compressed air supplied to the control valve to reduce the pressure of the cleaning fluid flowing through the control valve, so that the pressure of the cleaning fluid flowing through the control valve is equal to the target pressure value, I/P conversion When the receiver receives a large current signal output by the controller, the I/P converter increases the pressure of the compressed air supplied to the control valve to increase the pressure of the cleaning fluid flowing through the control valve, so that the cleaning fluid flowing through the control valve The pressure value is equal to the target pressure value. The flow switch measures the flow rate of the cleaning fluid flowing into the working chamber; the needle valve regulates the flow rate of the cleaning fluid flowing into the working chamber to the target flow rate.

In order to achieve the above object, another cleaning fluid flow control system provided by the present invention includes a main trunk road and a plurality of branches, wherein the main trunk road is provided with a control valve, a pressure sensor, a controller and a U/P converter. Flow switches and needle valves are provided on each road. The cleaning fluid flows through the control valve; the pressure sensor measures the pressure of the cleaning fluid flowing through the control valve and outputs the pressure value; the controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, according to the comparison As a result, a voltage signal is generated and transmitted. If the pressure value is greater than the target pressure value, the controller sends a smaller voltage signal. If the pressure value is less than the target pressure value, the controller sends a larger voltage signal; the U/P converter Receiving a voltage signal output by the controller and delivering compressed air having a corresponding pressure to the control valve. When the U/P converter receives a small voltage signal output by the controller, the U/P converter reduces the pressure of the compressed air supplied to the control valve. To reduce the pressure of the cleaning fluid flowing through the control valve, so that the pressure of the cleaning fluid flowing through the control valve is equal to the target pressure value, and the U/P converter receives a large voltage signal output by the controller, the U/P converter Increasing the pressure of the compressed air supplied to the control valve to increase the pressure of the cleaning fluid flowing through the control valve, so that the flow The pressure value of the cleaning fluid passing through the control valve is equal to the target pressure value. The flow switch measures the flow rate of the cleaning fluid flowing into the working chamber; the needle valve regulates the flow rate of the cleaning fluid flowing into the working chamber to the target flow rate.

Another object of the present invention is to provide a cleaning liquid flow control method, comprising the steps of: providing a control valve, a pressure sensor, an I/P converter and a controller to form a PID closed-loop control system; and a pressure sensor measuring flow control The pressure of the cleaning fluid of the valve outputs a pressure value; the controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, and generates and sends a current signal according to the comparison result, if the pressure value is greater than the target pressure value The controller sends a small current signal. If the pressure value is less than the target pressure value, the controller sends a larger current signal; the I/P converter receives the current signal output by the controller and delivers a corresponding pressure to the control valve. Compressed air, when the I/P converter receives a small current signal from the controller, the I/P converter reduces the pressure of the compressed air supplied to the control valve to reduce the pressure of the cleaning fluid flowing through the control valve, so that the flow The pressure value of the cleaning fluid of the control valve is equal to the target pressure value, and the I/P converter increases the delivery to the control when the I/P converter receives a large current signal output by the controller. Compressing air pressure to increase the pressure of the cleaning fluid flowing through the control valve, so that the pressure of the cleaning fluid flowing through the control valve is equal to the target pressure value; measuring the flow rate of the cleaning fluid flowing into the working chamber; and adjusting the cleaning fluid flowing into the working chamber The flow rate to the target flow rate.

Another object of the present invention is to provide another cleaning liquid flow control method, comprising the steps of: providing a control valve, a pressure sensor, a U/P converter and a controller to form a PID closed loop control system; and the pressure sensor measuring the flow through Controlling the pressure of the cleaning fluid of the valve and outputting the pressure value; the controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, and generates and sends a voltage signal according to the comparison result, if the pressure value is greater than the target pressure Value, the controller sends a smaller voltage signal, if the pressure value is less than the target pressure value, the controller sends a larger voltage signal; the U/P converter receives the voltage signal output by the controller and sends the corresponding signal to the control valve Compressed air of pressure, when the U/P converter receives a small voltage signal from the controller, the U/P converter reduces the pressure of the compressed air supplied to the control valve to reduce the pressure of the cleaning fluid flowing through the control valve, causing the flow The pressure value of the cleaning fluid passing through the control valve is equal to the target pressure value. When the U/P converter receives a large voltage signal from the controller, the U/P converter increases the delivery control. The valve compresses the pressure of the air to increase the pressure of the cleaning fluid flowing through the control valve such that the pressure of the cleaning fluid flowing through the control valve is equal to the target pressure value; the flow rate of the cleaning fluid flowing into the working chamber is measured; and the cleaning into the working chamber is regulated. The flow rate of the liquid to the target flow rate.

In summary, the cleaning fluid flow control system and the control method of the present invention utilize only one control valve, one pressure sensor, one I/P converter or U/P converter and one controller to constitute a PID closed-loop control system adjustment control The pressure of the cleaning fluid in the valve causes the pressure of the cleaning fluid flowing through the control valve to be equal to the target pressure value. The cleaning fluid flowing through the control valve and the pressure sensor is divided into a plurality of branches, and each branch uses a needle valve and a flow switch to adjust the flow rate of the cleaning liquid in the branch to the target flow rate. Take, for example, a three-branch cleaning fluid flow control system that utilizes a control valve, a pressure sensor, an I/P converter or U/P converter, a controller, three needle valves, and Three flow switches supply a precise and steady flow of cleaning fluid to the working chamber. The traditional cleaning fluid flow control system requires three control valves, three pressure sensors, three I/P converters or three U/P converters, three controllers and three flow meters. In contrast, the cleaning fluid flow control system of the present invention can save two control valves, two pressure sensors, two I/P converters or U/P converters, two controllers, and the invention adopts Flow switches are also less expensive than conventional flow meters. Therefore, the cost of the present invention can be greatly reduced, and the structure of the present invention is simple.

10‧‧‧Control valve

20‧‧‧ Pressure Sensor

30‧‧‧I/P converter

30’‧‧‧U/P converter

40‧‧‧ Controller

50‧‧‧needle valve

60‧‧‧Flow switch

70‧‧‧Working chamber

80‧‧‧ switch valve

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a first embodiment of a cleaning fluid flow control system of the present invention.

Figure 2 is a block diagram of a second embodiment of the cleaning fluid flow control system of the present invention.

Figure 3 is a flow chart showing a first embodiment of the cleaning liquid flow control method of the present invention.

Figure 4 is a flow chart showing a second embodiment of the cleaning liquid flow control method of the present invention.

Fig. 5 is a graph showing the flow rate of the cleaning liquid controlled by the cleaning liquid flow rate control method of the present invention.

In order to explain the technical content, structural features, objects and effects of the present invention in detail, the embodiments will be described in detail below with reference to the accompanying drawings.

Referring to Figure 1, a first embodiment of a cleaning fluid flow control system of the present invention is illustrated. The cleaning fluid flow control system of the present invention includes a main trunk circuit, and a control valve 10, a pressure sensor 20, a controller 40 and an I/P converter 30 are disposed on the main trunk. Control valve 10, pressure sensor 20, controller 40 and I/P converter 30 form a PID closed loop control system. The pressure sensor 20 measures the pressure of the cleaning liquid flowing through the control valve 10 and outputs a pressure electric signal. After receiving the pressure electrical signal output by the pressure sensor 20, the controller 40 generates and transmits a corresponding current signal to the I/P converter 30. The I/P converter 30 receives the current signal output from the controller 40 and then supplies compressed air having a corresponding pressure to the control valve 10, thereby adjusting the pressure of the cleaning liquid in the control valve 10. Through the automatic adjustment of the PID closed-loop control system, the pressure of the cleaning fluid flowing through the control valve 10 and the pressure sensor 20 can be maintained at a set value.

Referring to Figure 2, a second embodiment of the cleaning fluid flow control system of the present invention is illustrated. The cleaning fluid flow control system of the present invention comprises a main trunk circuit, and a control valve 10, a pressure sensor 20, a controller 40 and a U/P converter 30' are disposed on the main trunk. Control valve 10, pressure sensor 20, controller 40 and U/P converter 30' form a PID closed loop control system. The pressure sensor 20 measures the pressure of the cleaning liquid flowing through the control valve 10. And output a pressure electric signal. After receiving the pressure electrical signal output by the pressure sensor 20, the controller 40 generates and transmits a corresponding voltage signal to the U/P converter 30'. The U/P converter 30' receives the voltage signal output from the controller 40 and then delivers compressed air having a corresponding pressure to the control valve 10, thereby adjusting the pressure of the cleaning liquid in the control valve 10. Through the automatic adjustment of the PID closed-loop control system, the pressure of the cleaning fluid flowing through the control valve 10 and the pressure sensor 20 can be maintained at a set value.

Please continue to refer to Figures 1 and 2. The cleaning fluid flowing through the control valve 10 and the pressure sensor 20 can be divided into a plurality of branches according to different process requirements, for example, in the first embodiment and the second embodiment, flowing through the control valve 10 and the pressure sensor 20 The cleaning fluid is divided into three branches, each of which includes a needle valve 50, a flow switch 60, and a working chamber 70. The cleaning fluid of each branch flows through the needle valve 50 and the flow switch 60 and flows into the working chamber 70 for cleaning the wafer. A flow switch 60 in each branch measures the flow rate of the cleaning fluid in the branch. The needle valve 50 adjusts the flow rate of the cleaning liquid in the branch according to the flow rate measured by the flow switch 60 until the flow rate of the cleaning liquid in the branch reaches the flow rate required by the process, and the needle valve 50 may be a manual valve. Preferably, each branch further includes an on-off valve 80 for allowing or preventing the flow of cleaning fluid into the working chamber 70.

According to a first embodiment of the cleaning fluid flow control system of the present invention, the working principle of the cleaning fluid flow control system of the present invention is briefly described below. The pressure sensor 20 instantaneously measures the pressure of the cleaning fluid flowing through the control valve 10 and transmits the measured pressure value to the controller 40. The controller 40 receives the pressure value and compares the pressure value with a preset target pressure value. If Pc>Pt, the controller 40 sends a smaller current signal to the I/P converter 30, and the I/P conversion The receiver 30 receives the smaller current signal output from the controller 40 and then reduces the pressure of the compressed air supplied to the control valve 10 to reduce the pressure of the cleaning fluid flowing through the control valve 10 such that the pressure of the cleaning fluid flowing through the control valve 10 is equal to Target pressure value; if Pc < Pt, the controller 40 sends a larger current signal to the I/P converter 30, and the I/P converter 30 receives the larger current signal output by the controller 40 and increases the delivery to the control. The valve 10 compresses the pressure of the air to increase the pressure of the cleaning fluid flowing through the control valve 10 such that the pressure of the cleaning fluid flowing through the control valve 10 is equal to the target pressure value; if Pc = Pt, the current value in each branch is The flow rate of the cleaning solution is compared with a target flow rate. If Fc=Ft, the adjustment of the cleaning fluid pressure and flow rate is completed, and the system will maintain a steady state; if Fc>Ft, the needle valve 50 in the corresponding branch needs to be adjusted. Small, thereby reducing the flow rate of the cleaning liquid in the corresponding branch, so that Fc=Ft, at the same time, the pressure of the cleaning liquid flowing through the control valve 10 is increased, thereby causing Pc>Pt, and the controller 40 sends a smaller one. The current signal is sent to the I/P converter 30, and the I/P converter 30 receives The smaller current signal output by the controller 40 then reduces the pressure of the compressed air supplied to the control valve 10 to reduce the pressure of the cleaning fluid flowing through the control valve 10 such that the pressure of the cleaning fluid flowing through the control valve 10 is equal to the target pressure value. If Fc < Ft, the needle valve 50 in the corresponding branch needs to be adjusted to increase the flow rate of the cleaning liquid in the corresponding branch so that Fc = Ft, and at the same time, the pressure of the cleaning liquid flowing through the control valve 10 Lowering, resulting in Pc < Pt, the controller 40 sends a larger current signal to the I/P converter 30, and the I/P converter 30 receives the larger current signal output by the controller 40 and increases the delivery to the control valve. The pressure of the compressed air is increased to increase the pressure of the cleaning liquid flowing through the control valve 10 such that the pressure of the cleaning liquid flowing through the control valve 10 is equal to the target pressure value. Where Pc is The measured pressure of the cleaning fluid flowing through the control valve 10, Pt is the target pressure value of the cleaning fluid flowing through the control valve 10, Fc is the instantaneously measured flow rate of the cleaning fluid in the branch, and Ft is the cleaning in the branch. The target flow rate of the liquid.

According to a second embodiment of the cleaning fluid flow control system of the present invention, the working principle of the cleaning fluid flow control system of the present invention is briefly described below. The pressure sensor 20 instantaneously measures the pressure of the cleaning fluid flowing through the control valve 10 and transmits the measured pressure value to the controller 40. The controller 40 receives the pressure value and compares the pressure value with a preset target pressure value. If Pc>Pt, the controller 40 sends a smaller voltage signal to the U/P converter 30', U/P conversion. The receiver 30' receives the smaller voltage signal output by the controller 40 and then reduces the pressure of the compressed air supplied to the control valve 10 to reduce the pressure of the cleaning fluid flowing through the control valve 10 so that the pressure of the cleaning fluid flowing through the control valve 10 Equal to the target pressure value; if Pc < Pt, the controller 40 sends a larger voltage signal to the U/P converter 30', and the U/P converter 30' receives the larger voltage signal output by the controller 40 and then increases. The pressure supplied to the control valve 10 compresses the air to increase the pressure of the cleaning fluid flowing through the control valve 10 such that the pressure of the cleaning fluid flowing through the control valve 10 is equal to the target pressure value; if Pc = Pt, each will be The current flow rate of the cleaning fluid in the road is compared with a target flow rate. If Fc=Ft, the adjustment of the pressure and flow rate of the cleaning fluid is completed, and the system will maintain a steady state; if Fc>Ft, the needle in the corresponding branch is required. The valve 50 is adjusted to reduce the flow of the cleaning fluid in the corresponding branch Fc = Ft, at the same time, the pressure of the cleaning fluid flowing through the control valve 10 is increased, resulting in Pc > Pt, and the controller 40 sends a smaller voltage signal to the U/P converter 30', U/ The P converter 30' receives the smaller voltage signal output by the controller 40 and then reduces the input. The pressure of the compressed air is sent to the control valve 10 to reduce the pressure of the cleaning liquid flowing through the control valve 10, so that the pressure value of the cleaning liquid flowing through the control valve 10 is equal to the target pressure value; if Fc < Ft, the corresponding branch is required The needle valve 50 is adjusted to increase the flow rate of the cleaning liquid in the corresponding branch so that Fc=Ft, and at the same time, the pressure of the cleaning liquid flowing through the control valve 10 is lowered, thereby causing Pc<Pt, and the controller 40 transmits A larger voltage signal is applied to the U/P converter 30'. The U/P converter 30' receives the larger voltage signal output by the controller 40 and increases the pressure of the compressed air supplied to the control valve 10 to increase the flow. The pressure of the cleaning liquid of the control valve 10 is such that the pressure value of the cleaning liquid flowing through the control valve 10 is equal to the target pressure value. Wherein, Pc is the instantaneously measured pressure of the cleaning fluid flowing through the control valve 10, Pt is the target pressure value of the cleaning fluid flowing through the control valve 10, and Fc is the instantaneously measured flow rate of the cleaning fluid in the branch, Ft is The target flow rate of the cleaning fluid in the branch.

Referring to FIG. 3, a first cleaning liquid flow control method according to the present invention is disclosed. The method includes the following steps: S1, setting a target pressure value of the cleaning liquid flowing through the control valve 10; S2, and a cleaning liquid flow having a certain pressure. Through the control valve 10, the pressure of the cleaning liquid approaches the target pressure value; S3, the pressure sensor 20 immediately measures the pressure of the cleaning liquid flowing through the control valve 10, and transmits the measured pressure value to the controller 40; S4, control The controller 40 receives the pressure value and compares the pressure value with the target pressure value. If Pc=Pt, the step S5 is performed; if Pc>Pt, the controller 40 sends a smaller current signal to the I/P converter 30, I. The /P converter 30 receives the smaller current signal output by the controller 40 and then reduces the delivery to the control valve 10 Compressing air pressure to reduce the pressure of the cleaning fluid flowing through the control valve 10, and returning to step S3; if Pc < Pt, the controller 40 sends a larger current signal to the I/P converter 30, the I/P converter 30 receives the larger current signal outputted by the controller 40, increases the pressure of the compressed air supplied to the control valve 10 to increase the pressure of the cleaning fluid flowing through the control valve 10, and returns to step S3, wherein Pc is instantaneously measured. The pressure of the cleaning liquid flowing through the control valve 10, Pt is the target pressure value of the cleaning liquid flowing through the control valve 10; S5, comparing the current flow rate of the cleaning liquid in each branch with a target flow rate, if Fc =Ft, then the adjustment of the cleaning fluid pressure and flow rate is completed, the system will maintain a steady state; if Fc>Ft, the needle valve 50 in the corresponding branch is adjusted to be small, thereby reducing the flow rate of the cleaning liquid in the corresponding branch, and At the same time, the pressure of the cleaning liquid flowing through the control valve 10 is increased, thereby causing Pc>Pt, and the process returns to step S3; if Fc<Ft, the needle valve 50 in the corresponding branch is adjusted to be larger, thereby increasing the corresponding branch. The flow rate of the cleaning liquid in the road, and at the same time, the cleaning liquid flowing through the control valve 10 Pressure reduction, resulting in Pc <Pt, return to step S3 at this time, wherein, the cleaning liquid is the Fc immediate branch flow rate measured, the washing liquid is Ft branch target flow rate.

Considering that in the actual process, the machining process of the working chambers 70 of the branches is not necessarily synchronized, which means that the switching valves 80 of a certain branch or a certain number of branches will open or close with time. At the moment when each branch switch valve 80 is opened or closed, a sudden change in the flow rate and pressure of the cleaning fluid on the total dry road, and fluctuations in the pressure and flow rate of the cleaning fluid of the other branches are caused. In addition, the number of open switching valves 80, that is, the number of open branches, also causes the pressure of the cleaning fluid flowing through the pressure sensor 20 on the total dry road. Differently, since the flow rate of the cleaning liquid of each branch changes, the flow rate and pressure of the cleaning liquid on the total dry road change accordingly. For example, the number of open roads is increased from one way to two. If the flow rate of the cleaning liquid per channel is 2 lpm, then the flow rate of the cleaning liquid on the total dry road increases from 2 lpm to 4 lpm, in order to increase the supply of cleaning liquid, I The /P converter 30 needs to increase the pressure of the compressed air supplied to the control valve 10; meanwhile, the flow rate of the cleaning liquid of the second branch rises from 0 lpm for a period of time after the opening and closing valve 80 of the second branch is opened. It takes a certain time to reach 2lpm, during which the flow of the cleaning fluid is unstable, and the unstable state generally lasts for a few seconds. During this time period, the pressure and flow of the cleaning fluid of the main trunk road and each branch will fluctuate. At this time, PID adjustment is performed, it is difficult to achieve the desired control effect, and even the I/P converter 30 is increased. The control valve 10 compresses the fluctuations in the pressure of the air, which eventually causes the flow of the other branches to fluctuate.

In order to solve the above problem, the cleaning liquid flow control method of the present invention further includes the following steps before performing steps S1 to S5: first, setting the pressure of the compressed air supplied from the I/P converter 30 to the control valve 10 according to the number of open branches. The value, the number of ways in which the branch is open, and the one-to-one correspondence between the pressure value of the compressed air supplied from the I/P converter 30 to the control valve 10 can be obtained in advance by an experimental method; then, the I/P conversion is performed while opening the branches. The device 30 delivers the compressed air having the set pressure value to the control valve 10 for a period of time until the change in the pressure and flow rate of the cleaning liquid on the total dry road due to the switch of the branch tends to be stable, and then PID adjustment is performed, so that The pressure value of the cleaning liquid flowing through the control valve 10 is equal to the target pressure value.

In the process of executing steps S1 to S5, if it is necessary to change the number of ways in which the branch is open, the flow returns to the step "Set the pressure value of the compressed air supplied to the control valve 10 by the I/P converter 30 in accordance with the number of open branches".

Referring to FIG. 4, a second method for controlling the flow rate of the cleaning liquid of the present invention is disclosed. The method includes the following steps: S10, setting a target pressure value of the cleaning liquid flowing through the control valve 10; S20, and a cleaning liquid flow having a certain pressure. Through the control valve 10, the pressure of the cleaning fluid is close to the target pressure value; S30, the pressure sensor 20 immediately measures the pressure of the cleaning fluid flowing through the control valve 10, and transmits the measured pressure value to the controller 40; S40, control The controller 40 receives the pressure value and compares the pressure value with the target pressure value. If Pc=Pt, the step S50 is performed; if Pc>Pt, the controller 40 sends a smaller voltage signal to the U/P converter 30'. The U/P converter 30' receives the smaller voltage signal output by the controller 40 and then reduces the pressure of the compressed air supplied to the control valve 10 to reduce the pressure of the cleaning fluid flowing through the control valve 10, and returns to step S30; if Pc< Pt, the controller 40 sends a large voltage signal to the U/P converter 30', and the U/P converter 30' receives the larger voltage signal output by the controller 40 and increases the compressed air supplied to the control valve 10. Pressure to increase the pressure of the cleaning fluid flowing through the control valve 10 And return to step S30, wherein Pc is the instantaneously measured pressure of the cleaning fluid flowing through the control valve 10, Pt is the target pressure value of the cleaning fluid flowing through the control valve 10; S50, the current value in each branch The flow rate of the cleaning solution is compared with a target flow rate. If Fc=Ft, the adjustment of the cleaning fluid pressure and flow rate is completed, and the system will maintain a steady state; if Fc>Ft, the needle in the corresponding branch will be maintained. The valve 50 is adjusted to be small, thereby reducing the flow rate of the cleaning liquid in the corresponding branch, and at the same time, the pressure of the cleaning liquid flowing through the control valve 10 is increased, thereby causing Pc>Pt, and returning to step S30; if Fc<Ft , the needle valve 50 in the corresponding branch is adjusted to increase the flow rate of the cleaning liquid in the corresponding branch, and at the same time, the pressure of the cleaning liquid flowing through the control valve 10 is lowered, thereby causing Pc<Pt, and returning at this time Step S30, wherein Fc is the flow rate of the cleaning liquid in the branch measured immediately, and Ft is the target flow rate of the cleaning liquid in the branch.

Similar to the first cleaning liquid flow control method, the method further includes the following steps before performing steps S10 to S50: first, the U/P converter 30' is configured to be supplied to the control valve 10 according to the number of open branches. The pressure value of the air, the number of open paths of the branch, and the one-to-one correspondence between the pressure value of the compressed air supplied from the U/P converter 30' to the control valve 10 can be obtained by an experimental method in advance; then, the branches are opened simultaneously. The U/P converter 30' delivers compressed air having a set pressure value to the control valve 10 for a period of time until the change in the pressure flow rate of the cleaning liquid on the total dry road due to the switch of the branch tends to be stable, and then, proceeds The PID is adjusted such that the pressure value of the cleaning fluid flowing through the control valve 10 is equal to the target pressure value.

In the process of executing steps S10 to S50, if it is necessary to change the number of ways in which the branch is opened, the returning step "sets the pressure value of the compressed air supplied to the control valve 10 by the U/P converter 30' according to the number of open branches".

Please refer to FIG. 5. FIG. 5 is a graph of controlling the flow rate of the cleaning liquid by using the cleaning liquid flow control method of the present invention. In Fig. 5, a broken line C1 indicates a target pressure value, and a broken line C2 indicates an actual pressure value. In area A, indicating the place Some of the 9-way on-off valves 80 are closed. In the area B, the on-off valves 80 indicating the 1-way to the 9-way are gradually opened in sequence, and the PID adjustment is started at the same time. The broken line at the top of the area B indicates the current sent by the controller 40 to the I/P converter, and the 9-way on-off valve can be seen. During the sequential opening of 80, the current sent by the controller 40 to the I/P converter is gradually increased. In area C, it is indicated that all of the nine-way on-off valves 80 have all been opened. As can be seen from FIG. 5, when the 1-way to 9-way on-off valve 80 is gradually opened, the pressure value of the cleaning liquid flowing through the control valve 10 is always consistent with the target pressure value through the PID adjustment, and the cleaning is performed in each branch. The flow rate of the liquid is maintained at the target flow rate.

It can be seen from the above that the cleaning liquid flow control system and the control method of the present invention can supply the cleaning fluid of the precise and stable flow rate to the working chamber 70 through the automatic adjustment of the PID closed-loop control system. Even if the upstream cleaning fluid supply is unstable, it is still possible to supply the working chamber 70 with a precise and stable flow of cleaning fluid under the automatic adjustment of the PID closed-loop control system. In addition, when the on-off valve 80 in one or several branches is opened or closed, the flow rate of the cleaning fluid in the other branches is not affected by the automatic adjustment of the PID closed-loop control system.

The cleaning fluid flow control system and control method of the present invention constitutes a PID closed-loop control system by using only one control valve 10, one pressure sensor 20, one I/P converter 30 or U/P converter 30' and one controller 40. The pressure of the cleaning liquid in the control valve 10 is adjusted. Each branch of the system utilizes a needle valve 50 and a flow switch 60 to regulate the flow rate of the cleaning fluid in the branch. Taking a cleaning fluid flow control system with three branches as an example, the system utilizes a control valve 10, a pressure sensor 20, and an I/P converter. A 30 or U/P converter 30', a controller 40, three needle valves 50 and three flow switches 60 supply a precise and steady flow of cleaning fluid to the working chamber 70. The conventional cleaning fluid flow control system requires three control valves 10, three pressure sensors 20, three I/P converters 30 or three U/P converters 30', three controllers 40 and three. Flow meters. In contrast, the cleaning fluid flow control system of the present invention can save two control valves 10, two pressure sensors 20, two I/P converters 30 or U/P converters 30', and two controllers 40. Moreover, the flow switch 60 employed in the present invention is also less expensive than the conventionally employed flow meter. Therefore, the cost of the present invention can be greatly reduced, and the structure of the present invention is simple.

In summary, the cleaning liquid flow control system and the control method of the present invention have been specifically and specifically disclosed by the above-described embodiments and related drawings, so that those skilled in the art can implement them. The above-mentioned embodiments are only intended to illustrate the invention, and are not intended to limit the invention. The scope of the invention should be defined by the scope of the invention. Changes in the number of elements described herein or substitution of equivalent elements are still within the scope of the invention.

10‧‧‧Control valve

20‧‧‧ Pressure Sensor

30‧‧‧I/P converter

40‧‧‧ Controller

50‧‧‧needle valve

60‧‧‧Flow switch

70‧‧‧Working chamber

80‧‧‧ switch valve

Claims (16)

A cleaning fluid flow control system includes: a total trunk road and a plurality of branches, wherein the total trunk road is provided with: a control valve through which the cleaning fluid flows; and a pressure sensor that flows through the control valve The pressure of the cleaning liquid outputs a pressure value; the controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, and generates and sends a current signal according to the comparison result, if the pressure value is greater than the target a pressure value, the controller sends a smaller current signal, if the pressure value is less than the target pressure value, the controller sends a larger current signal; an I/P converter receives the current output by the controller Transmitting and delivering compressed air having a corresponding pressure to the control valve, the I/P converter reducing the delivery to the control valve when the I/P converter receives a smaller current signal output by the controller Compressing air pressure to reduce pressure of the cleaning fluid flowing through the control valve such that a pressure value of the cleaning fluid flowing through the control valve is equal to a target pressure value, the I/P converter receiving the controller When a larger current signal is emitted, the I/P converter increases the pressure of the compressed air supplied to the control valve to increase the pressure of the cleaning fluid flowing through the control valve such that it flows through the control valve The pressure of the cleaning liquid is equal to the target pressure value; each branch is provided with: a flow switch for measuring the flow rate of the cleaning liquid flowing into the working chamber; and a needle valve for adjusting the flow rate of the cleaning liquid flowing into the working chamber to the target flow rate. The cleaning liquid flow control system according to claim 1, wherein the cleaning liquid flowing through the control valve and the pressure sensor is divided into a plurality of Branch road. The cleaning liquid flow control system according to claim 2, wherein if the pressure of the cleaning fluid flowing through the control valve measured by the pressure sensor is equal to a target pressure value, each branch is The current flow rate of the cleaning fluid is compared to a target flow rate. If the current flow rate of the cleaning fluid is equal to the target flow rate, the adjustment of the cleaning fluid pressure and flow rate is completed. The cleaning liquid flow control system according to claim 2, wherein if the pressure of the cleaning fluid flowing through the control valve measured by the pressure sensor is equal to a target pressure value, each branch is The current flow rate of the cleaning liquid is compared with a target flow rate. If the current flow rate of the cleaning liquid is greater than the target flow rate, the needle valve in the corresponding branch is adjusted to be smaller, thereby reducing the flow rate of the cleaning liquid in the corresponding branch, so that the corresponding branch The flow rate of the cleaning liquid in the road is equal to the target flow rate; if the current flow rate of the cleaning liquid is less than the target flow rate, the needle valve in the corresponding branch is adjusted to increase the flow rate of the cleaning liquid in the corresponding branch, so that the cleaning in the corresponding branch is performed. The flow rate of the liquid is equal to the target flow rate. The cleaning liquid flow control system according to claim 1, wherein the switching valve is further provided on each of the branches for allowing or preventing the cleaning liquid from flowing into the working chamber. The cleaning fluid flow control system according to claim 1, wherein the control valve, the pressure sensor, the I/P converter, and the controller constitute a PID closed-loop control system. A cleaning fluid flow control system includes: a total trunk road and a plurality of branches, wherein the total trunk road is provided with: a control valve through which the cleaning fluid flows; and a pressure sensor that flows through the control valve The pressure of the cleaning liquid outputs a pressure value; the controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, and generates and sends a voltage signal according to the comparison result, if the pressure value is greater than the target a pressure value, the controller sends a smaller voltage signal, if the pressure value is less than the target pressure value, the controller sends a larger voltage signal; the U/P converter receives the voltage output by the controller Transmitting and delivering compressed air having a corresponding pressure to the control valve, the U/P converter reducing delivery to the control valve when the U/P converter receives a smaller voltage signal output by the controller Compressing air pressure to reduce a pressure of the cleaning fluid flowing through the control valve such that a pressure value of the cleaning fluid flowing through the control valve is equal to a target pressure value, the U/P converter receiving the controller The U/P converter increases the pressure of the compressed air supplied to the control valve to increase the pressure of the cleaning fluid flowing through the control valve such that it flows through the control valve The pressure of the cleaning liquid is equal to the target pressure value; each branch is provided with: a flow switch for measuring the flow rate of the cleaning liquid flowing into the working chamber; and a needle valve for adjusting the flow rate of the cleaning liquid flowing into the working chamber to the target flow rate. The cleaning liquid flow control system according to claim 7, characterized in that the cleaning liquid flowing through the control valve and the pressure sensor is divided into a plurality of branches. The cleaning liquid flow control system according to claim 8, characterized in that, if the pressure of the cleaning liquid flowing through the control valve measured by the pressure sensor is equal to the target pressure value, each branch is The current flow rate of the cleaning fluid is compared to a target flow rate. If the current flow rate of the cleaning fluid is equal to the target flow rate, the adjustment of the cleaning fluid pressure and flow rate is completed. The cleaning liquid flow control system according to claim 8, characterized in that, if the pressure of the cleaning liquid flowing through the control valve measured by the pressure sensor is equal to the target pressure value, each branch is The current flow rate of the cleaning liquid is compared with a target flow rate. If the current flow rate of the cleaning liquid is greater than the target flow rate, the needle valve in the corresponding branch is adjusted to be smaller, thereby reducing the flow rate of the cleaning liquid in the corresponding branch, so that the corresponding branch The flow rate of the cleaning liquid in the road is equal to the target flow rate; if the current flow rate of the cleaning liquid is less than the target flow rate, the needle valve in the corresponding branch is adjusted to increase the flow rate of the cleaning liquid in the corresponding branch, so that the cleaning in the corresponding branch is performed. The flow rate of the liquid is equal to the target flow rate. The cleaning liquid flow control system according to claim 7, characterized in that: on each of the branches, an on-off valve is further provided for allowing or preventing the cleaning liquid from flowing into the working chamber. The cleaning fluid flow control system according to claim 7, characterized in that the control valve, the pressure sensor, the U/P converter and the controller constitute a PID closed-loop control system. A cleaning fluid flow control method includes the following steps: Providing a control valve, a pressure sensor, an I/P converter and a controller to form a PID closed loop control system; using the pressure sensor to measure a pressure of a cleaning fluid flowing through the control valve and outputting a pressure value; The controller receives the pressure value output by the pressure sensor and compares the pressure value with the target pressure value, generates and sends a current signal according to the comparison result, and if the pressure value is greater than the target pressure value, the controller sends a smaller Current signal, if the pressure value is less than the target pressure value, the controller sends a larger current signal; receiving, by the I/P converter, a current signal output by the controller and delivering the control signal to the control valve Compressed air of a corresponding pressure, the I/P converter reducing a pressure of the compressed air supplied to the control valve to reduce a flow through when the I/P converter receives a smaller current signal output by the controller The pressure of the cleaning fluid of the control valve is such that the pressure value of the cleaning fluid flowing through the control valve is equal to the target pressure value, and the I/P converter receives a large current signal output by the controller. The I/P converter increases a pressure of the compressed air supplied to the control valve to increase a pressure of the cleaning liquid flowing through the control valve such that a pressure value of the cleaning liquid flowing through the control valve is equal to a target pressure value; The flow rate of the cleaning liquid flowing into the working chamber is measured; the flow rate of the cleaning liquid flowing into the working chamber is adjusted to the target flow rate. The cleaning liquid flow rate control method according to claim 13, further comprising the steps of: setting a pressure value of the compressed air supplied to the control valve by the I/P converter according to the number of open branches; opening the branches At the same time, the I/P converter is sent to the control valve with settings. The compressed air of the pressure value is maintained for a period of time until the pressure of the cleaning liquid flowing through the control valve tends to be stable, and then PID adjustment is performed so that the pressure value of the cleaning liquid flowing through the control valve is equal to the target pressure value. A cleaning fluid flow control method includes the steps of: providing a control valve, a pressure sensor, a U/P converter, and a controller to form a PID closed-loop control system; and measuring, by the pressure sensor, a cleaning flow through the control valve Pressing the pressure of the liquid and outputting the pressure value; receiving, by the controller, the pressure value output by the pressure sensor and comparing the pressure value with the target pressure value, generating and transmitting a voltage signal according to the comparison result, if the pressure value is greater than the target a pressure value, the controller sends a smaller voltage signal, if the pressure value is less than the target pressure value, the controller sends a larger voltage signal; receiving the controller output by using the U/P converter a voltage signal and delivering compressed air having a corresponding pressure to the control valve, the U/P converter reducing the delivery to the small voltage signal output by the controller Controlling the pressure of the compressed air to reduce the pressure of the cleaning fluid flowing through the control valve such that the pressure of the cleaning fluid flowing through the control valve is equal to the target pressure value, and the U/P converter is connected When the controller outputs a large voltage signal, the U/P converter increases the pressure of the compressed air supplied to the control valve to increase the pressure of the cleaning fluid flowing through the control valve, so that the flow The pressure value of the cleaning fluid of the control valve is equal to the target pressure value; the flow rate of the cleaning fluid flowing into the working chamber is measured; and the flow rate of the cleaning fluid flowing into the working chamber is adjusted to the target flow rate. The cleaning liquid flow control method according to claim 15, further comprising the steps of: setting a pressure value of the compressed air supplied to the control valve by the U/P converter according to the number of open branches; opening the branches At the same time, the U/P converter supplies the compressed air having the set pressure value to the control valve for a period of time until the pressure of the cleaning liquid flowing through the control valve tends to be stable, and then PID adjustment is performed to make the cleaning through the control valve The pressure value of the liquid is equal to the target pressure value.