Multi-loop flow control system and method of regulation

Abstract

The application discloses a kind of multi-loop flow control system and adjusting method, system includes main pipe, bypass pressure stabilizing branch and multiple test branch;The bypass pressure stabilizing branch and multiple test branch are parallelly connected with the main pipe, and the bypass pressure stabilizing branch is located between the main pipe and the multiple test branch;The bypass pressure stabilizing branch and the main pipe form pre-stabilized pressure loop, pressure control valve is arranged on the bypass pressure stabilizing branch, and the pressure of the pre-stabilized pressure loop is stabilized by the pressure control valve.By the multi-loop flow control system and adjusting method disclosed in the application, the stability of the system can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-channel flow control, in particular to a multi-loop flow control system and a regulating method. BACKGROUND

[0002] For the processes of electrolytic cell and fuel cell activation screening and durability test, a large number of material tests need to be carried out at the same time, and the use of single system is low in efficiency, and the use of multi-channel test system can greatly improve the test development efficiency. Multiple test pieces are tested in the same system, and each test piece has different operating conditions and different demand flow control.

[0003] On the one hand, the existing electrolytic cell multi-channel system uses busbars for natural shunt control, and the flow distribution is relatively fixed, and the flow distribution uniformity is affected by the test piece, so that the flow of each channel cannot be accurately controlled. On the other hand, the existing electrolytic cell multi-channel system uses channel regulating valves for channel flow regulation, but each channel will interfere with each other during adjustment, resulting in coupling of each channel flow regulation, and stable flow control of each channel cannot be achieved.

[0004] The prior art, patent No. CN110822778A, a kind of test platform with multi-channel pressure flow constant water cooling system and its application method, uses frequency conversion water pump to control loop pressure, and then stabilizes main road pressure, and each branch PID is passed to each branch ball valve opening degree Branch flow regulation. However, the main road pressure and branch flow control exist coupling in the control, and each branch cannot realize rapid flow regulation. SUMMARY

[0005] The technical problem to be solved by the present application is to solve the problem of unstable flow control of each channel in the existing electrolytic cell multi-channel system.

[0006] To solve the above technical problems, the present application provides the following technical scheme:

[0007] A multi-loop flow control system, comprising a main pipeline 100, a bypass pressure stabilizing branch 200 and a plurality of test branches 300; the bypass pressure stabilizing branch 200 and the plurality of test branches 300 are connected in parallel with the main pipeline 100, and the bypass pressure stabilizing branch 200 is located between the main pipeline 100 and the plurality of test branches 300;

[0008] The bypass pressure stabilizing branch 200 and the main pipeline 100 form a front pressure stabilizing loop I, and a pressure control valve 210 is arranged on the bypass pressure stabilizing branch 200, so that the pressure of the front pressure stabilizing loop I is stabilized by the pressure control valve 210.

[0009] Advantages: By designing a bypass pressure stabilizing branch, the control pressure control valve's adjustment ratio is wide, which can quickly self-adjust in a wide range of flow changes, absorb the flow changes during the adjustment of each test branch flow, maintain the stability of the test branch inlet pressure, avoid mutual interference between channels, reduce the coupling of flow regulation, improve the system stability and control accuracy.

[0010] In an embodiment of the present application, the main pipeline 100 comprises a circulating water tank 110, and a circulating water pump 120 and a main pipeline flow meter 130 connected in sequence with the outlet of the circulating water tank 110.

[0011] In an embodiment of the present application, the outlet pipe section of the main pipeline flow meter 130 branches, one branch being connected with the bypass pressure stabilizing branch 200, and the other branch being connected with a plurality of test branches 300; the main pipeline 100 further comprises a pressure test device 140, which is located on the pipe section before the outlet pipe section of the main pipeline flow meter 130 branches.

[0012] In an embodiment of the present application, the inlet port 2162 of the pressure control valve 210 is connected with the outlet pipe section of the main pipeline flow meter 130, the outlet port 2172 of the pressure control valve 210 is connected with the inlet of the circulating water tank 110, and the air inlet port 2121 of the pressure control valve 210 is connected with an air source.

[0013] In an embodiment of the present application, the air source pressure Px and the circuit pressure P0 of the pre-stabilizing circuit I act on the two sides of the diaphragm 218 of the pressure control valve 210, respectively, and the air source pressure Px and the circuit pressure P0 are in pressure balance state.

[0014] In an embodiment of the present application, each of the test branches 300 comprises a branch regulating valve 310 connected with the outlet of the main pipeline flow meter 130, and a branch flow meter 320 connected with the outlet of the branch regulating valve 310; the outlet of the branch flow meter 320 is connected with the inlet of the circulating water tank 110.

[0015] In an embodiment of the present application, the multi-circuit flow control system further comprises a controller 400, which comprises a plurality of branch PID control modules 410, a bypass branch control module 420 and a main pipeline control module 430;

[0016] The plurality of branch PID control modules 410 are respectively connected in communication with the branch regulating valves 310 and the branch flow meters 320 on the plurality of test branches 300, and adjust the valve opening degree of the branch regulating valves 310 on each branch;

[0017] The bypass branch control module 420 is in communication connection with the pressure control valve 210, and adjusts the adjustment ratio width of the pressure control valve 210;

[0018] The main pipeline control module 430 is in communication connection with the circulating water pump 120 and the main pipeline flow meter 130, and adjusts the rotating speed of the circulating water pump 120.

[0019] In an embodiment of the present application, when the system flow is coarsely adjusted, the valve flow of the pressure control valve 210 and the branch adjustment valve 310 is:

[0020] ;

[0021] In the formula, represents the valve flow through the valve body, represents the valve port flow area, represents the flow coefficient, represents the pressure difference before and after the valve port, represents the liquid density;

[0022] The bypass branch control module 420 and the plurality of branch PID control modules 410 adjust the adjustment ratio width of the pressure control valve 210 and the valve opening of the branch adjustment valve 310 according to the valve flow.

[0023] In an embodiment of the present application, when the branch PID control module 410 precisely controls the flow on each test branch, the flow on each test branch is obtained by the following formula:

[0024] ;

[0025] In the formula, represents the flow value on the current branch, represents the proportional coefficient, represents the integral coefficient, represents the differential coefficient, represents the deviation between the preset value and the control amount, represents the current data, represents the last data, represents k =0, ……, n the summation error of

[0026] According to the flow on each test branch, the valve opening of the branch adjustment valve 310 on each test branch is adjusted.

[0027] A regulating method of the multi-loop flow control system according to the above-mentioned, comprising:

[0028] When the system is running in stable working condition, the pre-valve and post-valve pressures of the pressure control valve 210 and the branch regulating valve 310 on each test branch are stable, the regulating ratio of the pressure control valve 210 is wide, and the valve opening of the branch regulating valve 310 on each test branch is adjusted;

[0029] When part of the test branches switches working condition, the branch regulating valve 310 is adjusted to regulate the flow according to the demand, at this time, the total flow capacity of each test branch changes, the gas source pressure Px of the pressure control valve 210 is adjusted, so that the gas source pressure Px and the loop pressure P0 of the pre-stabilized loop I are in pressure balance state, the changed flow during the working condition switching is absorbed, and the inlet pressure of each test branch is ensured to be stable.

[0030] Compared with the prior art, the beneficial effects of the present application are: the total loop pressure is controlled through the bypass stabilized branch, the flow of each branch is controlled through the branch regulating valve of each test branch and the feedback of the branch flow meter. The stable main pipe pressure reduces the influence of each test loop on the system during the adjustment process, avoids the coupling in the flow control, and stabilizes the total pipe pressure, thereby stabilizing the inlet pressure of the branch regulating valve of the test branch and improving the flow regulation accuracy of the test branch. Each test branch has an independent branch regulating valve and flow meter for PID closed-loop control, and the single-channel flow accurate control can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a multi-loop flow control system schematic diagram of an embodiment of the present application.

[0032] Figure 2 It is a pressure control valve schematic diagram of an embodiment of the present application.

[0033] Figure 3 It is a controller schematic diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to facilitate those skilled in the art to understand the technical scheme of the present application, the technical scheme of the present application will be further described in conjunction with the drawings of the specification.

[0035] The terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0036] Please refer to Figure 1As shown, the application provides a multi-circuit flow control system, which comprises a main pipe 100, a bypass pressure stabilizing branch 200 and a plurality of test branches 300. The bypass pressure stabilizing branch 200 and the plurality of test branches 300 are connected in parallel with the main pipe 100, and the bypass pressure stabilizing branch 200 is located between the main pipe 100 and the plurality of test branches 300. The bypass pressure stabilizing branch 200 and the main pipe 100 form a front pressure stabilizing circuit I, and a pressure control valve 210 is arranged on the bypass pressure stabilizing branch 200 to stabilize the pressure of the front pressure stabilizing circuit I.

[0037] As shown, Figure 1 In an embodiment of the application, the main pipe 100 comprises a circulating water tank 110, a circulating water pump 120 and a main pipe flow meter 130 connected in sequence with the outlet of the circulating water tank 110. The outlet pipe section of the main pipe flow meter 130 is bifurcated, one branch being connected with the bypass pressure stabilizing branch 200 and the other branch being connected with the plurality of test branches 300. The main pipe 100 further comprises a pressure test device 140 arranged on the pipe section before the bifurcation of the outlet pipe section of the main pipe flow meter 130. The circulating water pump 120 is a variable frequency water pump, and the pressure test device 140 is used to detect the inlet pressure of each bypass pressure stabilizing branch 200 and each test branch 300. The pressure test device 140 can also be arranged in multiple numbers, respectively located before and after the valve port of the pressure control valve 210 and each test branch regulating valve 310. Specifically, the pressure control valve 210 is a pressure sensor.

[0038] As shown, Figure 1 and Figure 2As shown, in an embodiment of the present application, the pressure control valve 210 is arranged at the outlet section of the main pipeline flow meter 130, for controlling the inlet pressure of each test branch. The pressure control valve 210 comprises a housing 211, a first cavity 212 and a second cavity 213 are arranged in the housing 211, and a connecting wall 214 is shared between the first cavity 212 and the second cavity 213. A partition wall 215 is arranged in the second cavity 213, for dividing the second cavity 213 into a first sub-cavity 216 and a second sub-cavity 217. An air inlet 2121 is arranged on the first cavity 212, a plurality of first communication ports 2161 are arranged on the connecting wall 214 at the first cavity 212 section, and an inlet port 2162 is further arranged on the first cavity 212. A plurality of second communication ports 2171 are arranged on the connecting wall 214 at the second cavity 213 section, and an outlet port 2172 is further arranged on the second cavity 213. The inlet port 2162 is connected with the outlet pipe section of the main pipeline flow meter 130, and the outlet port 2172 is connected with the inlet of the circulating water tank 110. The pressure control valve 210 further comprises a diaphragm 218, which is arranged in the first cavity 212. The air inlet 2121 of the pressure control valve 210 is connected with the gas source pipe, and the gas source pressure Px and the loop pressure P0 of the pre-stabilized pressure loop I act on the two sides of the diaphragm 218 of the pressure control valve 210 respectively, and the gas source pressure Px and the loop pressure P0 are in pressure balance state. The inlet port 2162, the diaphragm 218, the plurality of first communication ports 2161, the plurality of second communication ports 2171 and the outlet port 2172 form a flow channel. The pressure control valve 210 is for example a diaphragm type back pressure valve or a differential pressure type back pressure valve.

[0039] Referring to Figure 1 As shown, in an embodiment of the present application, each test branch 300 is independent of each other and is connected in parallel with the main pipeline 100, and is configured according to the system demand quantity. Each test branch 300 comprises a branch regulating valve 310 connected with the outlet pipe of the main pipeline flow meter 130, and a branch flow meter 320 connected with the outlet pipe of the branch regulating valve 310, and the outlet of the branch flow meter 320 is connected with the inlet pipe of the circulating water tank 110. The measured member 500 is located between the outlet section of the branch flow meter 320 and the inlet of the circulating water tank 110.

[0040] Referring to Figure 1 and Figure 3As shown, in an embodiment of the present application, the multi-loop flow control system further comprises a controller 400, which comprises a plurality of branch PID control modules 410, a bypass branch control module 420 and a main pipe control module 430. The plurality of branch PID control modules 410 are respectively connected with the branch regulating valves 310 and the branch flow meters 320 on the plurality of test branches 300, and adjust the valve opening degree of the branch regulating valves 310 on each branch. The bypass branch control module 420 is connected with the pressure control valve 210, and adjusts the regulating ratio width of the pressure control valve 210. The main pipe control module 430 is connected with the circulating water pump 120 and the main pipe flow meter 130, and adjusts the rotating speed of the circulating water pump 120. The branch PID control modules 410, the bypass branch control module 420 and the main pipe control module 430 can control the pressure control valve 210, the branch regulating valves 310 and the circulating water pump 120 through the flow feedback measured by the main pipe flow meter 130 and the branch flow meters 320, so as to perform flow regulation.

[0041] Please refer to Figures 1 to 3 As shown, in an embodiment of the present application, when the system flow is coarsely regulated, the valve flow of the pressure control valve 210 and the branch regulating valves 310 is:

[0042] ;

[0043] In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density.

[0044] The bypass branch control module 420 and the plurality of branch PID control modules 410 adjust the regulating ratio width of the pressure control valve 210 and the valve opening degree of the branch regulating valves 310 according to the valve flow.

[0045] When the branch PID control modules 410 accurately control the flow on each test branch, the flow on each test branch is obtained through the following formula:

[0046] ;

[0047] In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. In the formula, Q represents the valve flow, A represents the flow area of the valve port, K represents the flow coefficient, ΔP represents the pressure difference before and after the valve port, and ρ represents the liquid density. the last time, k =0,...., n the summation error.

[0048] According to the flow on each test branch, the valve opening of the branch regulating valve 310 on each test branch is adjusted. When the flow tested by the branch flow meter 320 on each test branch deviates from the set flow, or flow adjustment is performed, the valve opening of the adjustment branch regulating valve is controlled through PID proportional, integral, and differential operations, and further flow adjustment of the test branch is performed.

[0049] Referring to Figures 1 to 3 The present application also provides a regulating method of a multi-circuit flow control system, which comprises: when the system operates in a stable working condition, the pre-valve and post-valve pressures of the pressure control valve 210 and the branch regulating valve 310 on each test branch are stable, the regulating ratio of the pressure control valve 210 is wide, and the valve opening of the branch regulating valve 310 on each test branch is maintained.

[0050] When part of the test branches switch working conditions, the test branch adjusts the branch regulating valve 310 according to demand for flow adjustment, at this time, the total flow capacity of each test branch changes, the gas source pressure Px of the pressure control valve 210 is adjusted, so that the gas source pressure Px and the circuit pressure P0 of the pre-stabilizing circuit I are in pressure balance, the changing flow during the change of working conditions is absorbed, and the inlet pressure of each test branch is ensured to be stable.

[0051] If the inlet pressure of each test branch is not controlled, when part of the test branches switch working conditions, the test branch adjusts the branch regulating valve 310 according to demand for flow adjustment, at this time, the total flow capacity of each test branch changes, under the condition that there is no pressure control valve 210, the inlet pressure of each test branch changes, which leads to the change of the flow of each test branch, the branch PID control module 410 of each test branch controls the adjustment of the test branch flow, the branch regulating valve 310 adjusts the opening, and the target flow is maintained. Due to the large number of test branches, each test branch will be influenced and coupled in the flow adjustment, which leads to the oscillation of system flow and pressure regulation, and it is difficult to realize stable control of the flow.

[0052] ​It is apparent for a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Consequently, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than the above description, and it is therefore intended that all changes and modifications that fall within the meaning and range of equivalency of the claims be embraced therein, no matter

[0053] The above-described embodiments are merely exemplary and are not intended to limit the scope of the present application, and it is apparent for a person skilled in the art that various modifications and improvements can be made thereto without departing from the spirit of the present application, and such modifications and improvements are intended to fall within the scope of the present application.

Claims

1. A multi-loop flow control system, characterized in that, It includes the main pipeline (100), the bypass voltage stabilizing branch (200), and multiple test branches (300); the bypass voltage stabilizing branch (200) and the multiple test branches (300) are all connected in parallel with the main pipeline (100). The main pipeline (100) includes a circulating water tank (110), a circulating water pump (120) and a main pipeline flow meter (130) connected in sequence to the outlet of the circulating water tank (110); the outlet pipe of the main pipeline flow meter (130) branches, one branch is connected to the bypass pressure stabilizing branch (200), and the other branch is connected to multiple test branches (300); and the bypass pressure stabilizing branch (200) is located between the main pipeline (100) and the multiple test branches (300); The bypass stabilizing branch (200) and the main branch (100) form a pre-stabilizing circuit (I). A pressure control valve (210) is installed on the bypass stabilizing branch (200) to stabilize the pressure of the pre-stabilizing circuit (I). The pressure control valve (210) is a diaphragm back pressure valve. When some test branches switch operating conditions, the branch regulating valve (310) is adjusted as needed to regulate the flow. At this time, the total flow capacity of each test branch changes. The air source pressure (Px) of the pressure control valve (210) is adjusted so that the air source pressure (Px) and the loop pressure (P0) of the pre-stabilized pressure circuit (I) are in a pressure balance state, absorbing the flow changes during the change of operating conditions and ensuring the stability of the inlet pressure of each test branch. The inlet (2162) of the pressure control valve (210) is connected to the outlet section of the main pipeline flow meter (130), the outlet (2172) of the pressure control valve (210) is connected to the inlet of the circulating water tank (110), and the air inlet (2121) of the pressure control valve (210) is connected to the air source pipe. The gas source pressure (Px) and the circuit pressure (P0) of the pre-stabilized pressure circuit (I) act on the two sides of the diaphragm (218) of the pressure control valve (210), and the gas source pressure (Px) and the circuit pressure (P0) are in a pressure balance state. Each test branch (300) includes a branch regulating valve (310) connected to the outlet of the main branch flow meter (130), and a branch flow meter (320) connected to the outlet of the branch regulating valve (310); the outlet of the branch flow meter (320) is connected to the inlet of the circulating water tank (110).

2. The multi-loop flow control system according to claim 1, characterized in that, The main pipeline (100) also includes a pressure testing device (140) located on the pipeline section before the branch of the outlet section of the main pipeline flow meter (130).

3. The multi-loop flow control system according to claim 1, characterized in that, The multi-loop flow control system also includes a controller (400), which includes multiple branch PID control modules (410), bypass branch control modules (420) and main pipeline control modules (430). Multiple branch PID control modules (410) are connected to the branch regulating valves (310) and branch flow meters (320) on multiple test branches (300) respectively, and adjust the valve opening of the branch regulating valves (310) on each branch. The bypass branch control module (420) is communicatively connected to the pressure control valve (210) to adjust the adjustment ratio of the pressure control valve (210); The main pipeline control module (430) is communicatively connected to the circulating water pump (120) and the main pipeline flow meter (130) to adjust the speed of the circulating water pump (120).

4. The multi-loop flow control system according to claim 3, characterized in that, When coarsely adjusting the system flow rate, the valve flow rates through the pressure control valve (210) and the branch regulating valve (310) are as follows: ； In the formula, This is expressed as the valve flow rate through the valve body. This is expressed as the flow area at the valve orifice. Represented as flow coefficient, This is expressed as the pressure difference across the valve orifice. Expressed as liquid density; The bypass branch control module (420) and multiple branch PID control modules (410) adjust the regulating ratio of the pressure control valve (210) and the valve opening of the branch regulating valve (310) according to the valve flow.

5. A method for adjusting a multi-loop flow control system according to any one of claims 1-4, characterized in that, include: When the system is running under stable conditions, the pressure before and after the pressure control valve (210) and the branch regulating valve (310) on each test branch are stable, maintaining the adjustment ratio of the pressure control valve (210) and the valve opening of the branch regulating valve (310) on each test branch.

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