Thermal mass flow controller with pressure compensation and control method

Abstract

The application discloses a thermal mass flow controller with pressure compensation and a control method. The thermal mass flow controller comprises a main passage assembly, a monitoring assembly, a flow limiting assembly and a control assembly. The main passage assembly comprises a shunt passage communicated with the monitoring assembly and a flow limiting passage connected with the flow limiting assembly. The control assembly is electrically connected with the monitoring assembly and the flow limiting assembly. The monitoring assembly further comprises a pressure sensor. The pressure sensor is installed at an air inlet of the shunt passage. The pressure sensor is used for acquiring a pressure value of the shunt passage and transmitting the pressure value to the control assembly. The present application solves the problems that the existing equipment cannot control the flow due to the influence of pressure fluctuation and the problems that the flow overshoot or lag easily occurs due to the lack of a rapid pressure response mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid control, in particular to a thermal mass flow controller with pressure compensation and a control method. BACKGROUND

[0002] In the field of semiconductor equipment, experimental instruments, etc., the thermal mass flow controller is the core equipment to realize the accurate introduction of reaction gas. Its core working logic is: through a specific detection unit to monitor the medium flow in real time, and then control the opening and closing state of the valve according to the monitoring result, so as to adjust the medium flow introduced into the equipment and ensure the stability of the subsequent reaction or experiment process. At present, the mainstream thermal mass flow controller generally adopts a shunt detection method to simplify flow calculation, and combines the thermal sensing principle to realize flow monitoring, and cooperates with the dynamic adjustment of the valve, which can meet the basic demand of flow control in most conventional scenes, and is widely used in industrial production and scientific research experiments.

[0003] However, the existing gas mass flow controller still has some defects. On the one hand, the existing equipment only relies on the flow detection signal to adjust the valve action when controlling the flow, without fully considering the influence of pressure fluctuation in the medium passage: when the pressure in the passage fluctuates greatly, even if the valve maintains the preset opening and closing ratio, the pressure change may drive the valve to act abnormally, resulting in out-of-control medium flow and difficulty in maintaining stable flow output; on the other hand, the control logic of the existing equipment is mostly based on the flow detection result as a single feedback basis, lacking a rapid response and cooperative control mechanism for pressure change. When the pressure changes suddenly, the valve cannot adjust the action in advance according to the pressure change, which is prone to flow overshoot or adjustment lag, and it is difficult to meet the scene demand of high flow control precision and response speed in semiconductor equipment, experimental instruments, etc. SUMMARY

[0004] The purpose of the present application is to provide a thermal mass flow controller with pressure compensation and a control method to solve the problem of out-of-control flow caused by not considering the influence of pressure fluctuation in the existing equipment, and the problem of flow overshoot or lag due to lack of pressure rapid response mechanism.

[0005] One scheme of the present application provides a thermal mass flow controller with pressure compensation, which comprises a main passage assembly, a monitoring assembly, a flow limiting assembly and a control assembly. The main passage assembly comprises a shunt passage communicated with the monitoring assembly, and a flow limiting passage connected with the flow limiting assembly. The control assembly is electrically connected with the monitoring assembly and the flow limiting assembly.

[0006] The monitoring assembly further comprises a pressure sensor installed at the gas inlet of the shunt passage. The pressure sensor is used to obtain the pressure value of the shunt passage and transmit it to the control assembly.

[0007] The monitoring assembly is configured to acquire the flow value of the medium in the shunt passage and the pressure value of the shunt passage in real time and transmit to the control assembly; the control assembly is configured to acquire the flow value and the pressure value and control the flow limiting stroke of the flow limiting assembly according to the flow value and the pressure value; and the flow limiting assembly is configured to limit the flow of the medium in the flow limiting passage.

[0008] In one of the schemes, a main control shell is further arranged on the shunt passage, and a driving shell is further arranged outside the flow limiting assembly.

[0009] The control assembly comprises a signal processing module and a driving module, the signal processing module and the monitoring assembly are arranged in the main control shell, and the driving module is arranged in the driving shell; the signal processing module is configured to control the forward current or the reverse current of the driving module according to the flow value and the pressure value, and the driving module is configured to generate a forward magnetic field or a reverse magnetic field according to the forward current or the reverse current to control the flow limiting stroke of the flow limiting assembly.

[0010] In one of the schemes, the driving shell comprises a limiting groove for arranging the flow limiting assembly, and an annular cavity is arranged around the limiting groove, the flow limiting assembly is movably arranged in the limiting groove, and the driving module comprises a coil, the coil is wound around the annular cavity.

[0011] In one of the schemes, the monitoring assembly comprises a monitoring base, the monitoring base is arranged on the shunt passage, the monitoring base is provided with an upstream interface and a downstream interface, the upstream interface and the downstream interface are communicated through a monitoring pipeline, the monitoring pipeline is arranged with a flow sensor, and the flow sensor is electrically connected with the signal processing module.

[0012] In one of the schemes, the shunt passage comprises a first passage and a second passage separated by a separation part, the first passage is communicated with the upstream interface through a first branch, and the second passage is communicated with the downstream interface through a second branch.

[0013] In one of the schemes, the flow limiting passage comprises an upstream passage and a downstream passage separated by the flow limiting assembly, the upstream passage is communicated with the second passage, the flow limiting assembly is abutted at the outlet of the upstream passage, and the downstream passage is communicated with the limiting groove.

[0014] The flow limiting assembly comprises a first magnetic block fixedly installed at the top of the limiting groove and a second magnetic block movably connected in the limiting groove, the bottom of the second magnetic block is movably connected with a magnetic conducting block, a branch block is arranged in the upstream passage, a flow limiting branch is formed in the branch block, the magnetic conducting block is located at the outlet of the flow limiting branch and abuts against the branch block with a preset opening degree, and the preset opening degree is a flow gap formed between the magnetic conducting block and the branch block.

[0015] In one of the schemes, an elastic member is further arranged between the second magnetic block and the magnetic conducting block, and the elastic member is used to provide an elastic force for resetting the magnetic conducting block and abutting against the branch block with the preset opening degree when the coil is powered off, and to assist in stabilizing the flow limiting stroke of the magnetic conducting block when pressure fluctuation occurs.

[0016] One of the schemes of the present application further provides a thermal mass flow control method with pressure compensation, which applies the thermal mass flow controller with pressure compensation as described above, and comprises the following steps.

[0017] S1: obtaining a pressure value at the inlet of the shunt passage through the pressure sensor and obtaining a flow value of the medium in the shunt passage through the flow sensor;

[0018] S2: receiving the pressure value by the pressure compensation submodule of the signal processing module, calculating a pressure fluctuation amount, and generating a compensation signal in combination with the elastic force parameter of the elastic member;

[0019] S3: receiving the compensation signal by the driving module, adjusting the current of the coil according to the compensation signal, so as to balance the influence of pressure fluctuation on the flow limiting stroke of the magnetic conducting block and realize preliminary control of the flow of the medium in the flow limiting passage.

[0020] In one of the schemes, after step S3, the following steps are further included.

[0021] S4: receiving the flow value by the closed loop adjustment submodule of the signal processing module, and comparing the deviation of the flow value from a target flow value;

[0022] S5: correcting the compensation signal output by the pressure compensation submodule according to the deviation by the closed loop adjustment submodule, so that the current output by the driving module is double adapted to the deviation and the pressure fluctuation amount;

[0023] S6: adjusting the current of the coil according to the corrected compensation signal by the driving module, so as to accurately control the flow limiting stroke of the magnetic conducting block and realize closed loop control of the flow of the medium in the flow limiting passage.

[0024] In one of the schemes, in step S2, the following steps are further included.

[0025] S21: receiving the pressure value by a dynamic response submodule of the signal processing module, and analyzing a change rate of the pressure value;

[0026] S22: setting a current adjustment gradient of the coil according to the change rate of the pressure value by the dynamic response submodule;

[0027] S23: adjusting the current of the coil according to the current adjustment gradient by the driving module, so that the action speed of the magnetic conducting block matches the change rate of the pressure value.

[0028] Beneficial effects:

[0029] The pressure sensor and the flow sensor are arranged to synchronously collect the pressure value and the flow value of the shunt passage, a compensation signal is generated by the control assembly in combination with a pressure fluctuation amount and an elastic force parameter of the elastic member, a dynamic response submodule sets a current adjustment gradient according to a pressure change rate, a driving flow limiting component adjusts a flow limiting stroke of a magnetic conducting block, accurate compensation and rapid response to pressure fluctuation are achieved, interference of pressure fluctuation of the shunt passage on flow of the flow limiting passage is reduced, pressure compensation response time is shortened, and problems of flow overshoot, under-adjustment and lag are avoided, so that the flow of the medium is stably set in a target setting range.

[0030] The signal processing module and the monitoring component are integrated in the main control shell, and the driving module is independently arranged in the driving shell, so as to provide a dustproof and anti-interference protection space for the signal processing module, avoid electromagnetic interference generated during coil operation from affecting the collection accuracy of pressure and flow signals, and further improve the accuracy of flow control.

[0031] The elastic member and the electromagnetic drive are cooperated, automatic reset of the magnetic conducting block during power-off of the coil is realized, the minimum safety opening of the flow limiting branch is maintained, and the risk of process interruption caused by medium flow interruption after power-off is avoided.

[0032] The control method of the application forms the standardized flow control logic by step-by-step execution of processes such as pressure collection, compensation signal generation, current gradient adjustment, closed-loop correction, etc., facilitates integration of core components through a special control circuit board, and further reduces the hardware design complexity and production cost of the equipment; additionally, the overall automatic control is realized through preset regulation and control rules and algorithm programs, reduces manual intervention, and improves the stability and reliability of the equipment operation. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0034] Figure 1 It is a schematic diagram of the overall structure of one embodiment of the thermal mass flow controller with pressure compensation of the application;

[0035] Figure 2 It is a front view of one embodiment of the thermal mass flow controller with pressure compensation of the application;

[0036] Figure 3 It is a left view of one embodiment of the thermal mass flow controller with pressure compensation of the application;

[0037] Figure 4 It is a top view of one embodiment of the thermal mass flow controller with pressure compensation of the application;

[0038] Figure 5 It is a sectional view of one embodiment of the thermal mass flow controller with pressure compensation of the application;

[0039] Figure 6 It is Figure 5 It is a schematic diagram of the flow trajectory of the flowing medium in one embodiment;

[0040] Figure 7 It is a flowchart of the thermal mass flow control method with pressure compensation of the application.

[0041] Wherein, 1, main passage assembly; 11, shunt passage; 111, first passage; 112, second passage; 113, first branch; 114, second branch; 115, separation part; 12, flow limiting passage; 121, upstream passage; 122, downstream passage; 2, monitoring assembly; 21, pressure sensor; 22, monitoring base; 221, upstream interface; 222, downstream interface; 3, flow limiting assembly; 31, first magnetic block; 32, second magnetic block; 33, magnetic conducting block; 34, branch stopper; 35, flow limiting branch; 4, main control shell; 5, driving shell; 51, limiting groove; 52, annular air slot. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0043] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0044] In addition, if the embodiments of the present application involve descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0045] Please refer to Figures 1-7In one of the embodiments of the present application, a thermal mass flow controller with pressure compensation is provided, which comprises a main passage assembly 1, a monitoring assembly 2, a flow limiting assembly 3, and a control assembly. The main passage assembly 1 comprises a shunt passage 11 connected with the monitoring assembly 2, and a flow limiting passage 12 connected with the flow limiting assembly 3. The control assembly is electrically connected with the monitoring assembly 2 and the flow limiting assembly 3.

[0046] The monitoring assembly 2 further comprises a pressure sensor 21 installed at the gas inlet of the shunt passage 11. The pressure sensor 21 is used to obtain the pressure value of the shunt passage 11 and transmit it to the control assembly.

[0047] The monitoring assembly 2 is used to obtain the flow value of the medium in the shunt passage 11 and the pressure value of the shunt passage 11 in real time and transmit them to the control assembly. The control assembly is used to obtain the flow value and the pressure value, and control the flow limiting stroke of the flow limiting assembly 3 according to the flow value and the pressure value. The flow limiting assembly 3 is used to limit the flow of the medium in the flow limiting passage 12.

[0048] It should be noted that in actual work process, the monitoring assembly 2 first collects the pressure value of the gas inlet of the shunt passage 11 and the flow value of the medium in the shunt passage 11 through the pressure sensor 21 and the flow sensor (not shown) respectively, and synchronously transmits the two groups of data to the control assembly. After receiving the data, the control assembly will cooperatively analyze and logically operate the data according to the preset control rule, to generate a control signal for controlling the flow limiting stroke of the flow limiting assembly 3. Then the flow limiting assembly 3 receives the control signal and changes its flow limiting stroke according to the control signal, to adjust the medium flow state of the flow limiting passage 12, and finally realize stable control of the medium flow. The specific cooperative working principle of each assembly is described in detail in the following step description of the corresponding control method, and is not repeated here.

[0049] In this embodiment, the pressure value and the flow value of the shunt passage 11 are synchronously collected by the monitoring assembly 2 and transmitted to the control assembly, so that the control assembly can generate a control signal in combination with the two parameters, and then the flow limiting assembly 3 adjusts the flow limiting stroke according to the signal. Compared with the control method relying only on the flow signal, this method can effectively avoid the interference of pressure fluctuation of the shunt passage 11 on the medium flow of the flow limiting passage 12, reduce the flow out of control problem caused by pressure change, and further improve the stability of the medium flow in the flow controller.

[0050] In one of the embodiments, a main control housing 4 installed on the shunt passage 11 and a drive housing 5 installed outside the flow limiting assembly 3 are further included.

[0051] The control component includes a signal processing module and a drive module. The signal processing module and the monitoring component 2 are installed in the main control housing 4, and the drive module is installed in the drive housing 5. The signal processing module is used to control the forward current or reverse current of the drive module according to the flow rate value and the pressure value. The drive module is used to generate a positive magnetic field or a reverse magnetic field according to the forward current or the reverse current to control the current limiting stroke of the current limiting component 3.

[0052] It should be noted that in the actual design process, the signal processing module in the control component is integrated on a dedicated control circuit board. This circuit board integrates core components including a microprocessor, signal processing chip, and driver circuit. The microprocessor can be an MSP430 model, and the signal processing chip includes an instrumentation amplifier chip (AD620 model), an arithmetic multiplier chip (AD633 model), and an A / D converter. The conversion chip can be AD7705BR, and the H-bridge circuit in the drive circuit can be TB6612, DRV8833, L298N, etc. The function of the signal processing module is mainly realized by the microprocessor and supporting algorithm program on the circuit board, which is responsible for the calculation and analysis of pressure and flow signals. The drive module itself includes a coil (not shown), which relies on the drive circuit on the circuit board to convert the control signal output by the signal processing module into a current signal that can drive the coil (not shown) to move. Both the monitoring component 2 and the pressure sensor 21 need to be electrically connected to the circuit board. The drive module itself needs to be wound around the outside of the current limiting component 3 to realize its function. Therefore, ideally, a connection structure for fixing the circuit board can be set in the main control housing 4, and the corresponding components of the monitoring component 2 used to collect pressure and flow values ​​can be set in the main control housing 4. Then, the drive module that needs to be wound around the outside of the current limiting component 3 can be set separately in the drive housing 5.

[0053] It should be noted that in actual use, the drive module can be energized in both directions. By changing the direction of the current, the polarity of the magnetic field can be changed, thereby switching between the attractive and repulsive forces on the current limiting component 3. In addition, by adjusting the magnitude of the current, the direction and force of the current limiting component 3 can be flexibly controlled, thereby precisely controlling the current limiting stroke of the current limiting component 3, that is, achieving precise control of the current limiting stroke of the magnetic block 33 described below. Specifically, when the pressure of the diversion path 11 fluctuates, the pressure sensor 21 transmits the pressure signal to the signal processing module. The signal processing module calculates the direction and intensity of the compensation current according to the preset algorithm and outputs the corresponding control signal to the drive module, so that the coil (not shown) carries a positive or reverse control current, thereby generating a magnetic field of different polarities. The magnetic field acts on the magnetic components in the current limiting component 3, directly driving the magnetic block 33 to produce a displacement change.

[0054] In this embodiment, by the partition design of the main control shell 4 and the drive shell 5, the signal processing module and each component in the monitoring assembly 2 can be installed into the main control shell 4, which provides a dustproof and anti-interference protection space for the signal processing module and the monitoring assembly 2, thereby avoiding the electromagnetic interference effect of the coil (not shown) itself on the signal processing module when working. In addition, through the mechanism of bidirectional current driving, the displacement of the magnetic conducting block 33 can be adjusted in real time according to the pressure fluctuation direction, thereby shortening the pressure compensation response time and improving the overall dynamic stability.

[0055] In one embodiment, the drive shell 5 includes a limiting groove 51 for installing the flow limiting assembly 3, and an annular cavity arranged around the limiting groove 51. The flow limiting assembly 3 is movably installed in the limiting groove 51. The drive module includes a coil (not shown), and the coil (not shown) is arranged in the annular cavity.

[0056] It should be noted that in the actual design process, the electromagnetic driving function of the drive module is not only realized by the coil (not shown), but also can use an electromagnetic iron or other similar magnetic components with controllable magnetic field generation capability as an alternative solution. For example, the electromagnetic iron is designed in a cylindrical shape, which can be placed inside the annular cavity. As long as it can adjust the magnetic field strength or polarity through electrical signals to drive the flow limiting assembly 3 to realize the adjustment of the flow limiting stroke.

[0057] It should be additionally noted that the limiting groove 51 refers to a groove structure with a fixed shape arranged inside the drive shell 5, which can be realized by a rectangular or cylindrical groove, used to accommodate the flow limiting assembly 3 and provide guidance and constraint for the linear motion of the flow limiting assembly 3. The annular cavity refers to a continuous annular space formed around the outer wall of the limiting groove 51, which can be realized by a mechanically processed annular channel, used to accommodate the coil (not shown) and form a closed magnetic field loop. The coil (not shown) refers to a spiral winding made of conductive material, which can be made of copper wire or aluminum wire, used to generate a magnetic field to drive the flow limiting assembly 3 to act when energized.

[0058] Specifically, the flow limiting assembly 3 is constrained to move linearly inside the limiting groove 51, and the side wall of the limiting groove 51 and the flow limiting assembly 3 are in clearance fit, which allows the flow limiting assembly 3 to move freely in the axial direction and limits its radial deviation through mechanical contact; the annular layout of the annular cavity enables the coil (not shown) to form a uniformly distributed magnetic field along the movement direction of the flow limiting assembly 3, and when the coil (not shown) is energized, the magnetic field force acts along the axial direction of the flow limiting assembly 3, pushing the flow limiting assembly 3 to move in the limiting groove 51; during the movement of the flow limiting assembly 3, the guiding effect of the limiting groove 51 can avoid non-axial displacement caused by pressure fluctuation, and the magnetic field coverage range of the annular cavity can ensure that the flow limiting assembly 3 is always driven by a stable magnetic field within the full stroke range.

[0059] In this embodiment, through the cooperative design of the annular cavity and the limiting groove 51, the magnetic field generated by the coil (not shown) can completely surround the flow limiting assembly 3, and the magnetic field force is uniformly distributed in the axial direction, avoiding the problem of unbalanced driving force caused by uneven magnetic field layout; in addition, the lateral deviation caused by pressure fluctuation can be offset through the guiding constraint of the limiting groove 51, avoiding the flow control error caused by the deviation of the movement trajectory of the flow limiting assembly 3.

[0060] In one of the embodiments, the monitoring assembly 2 comprises a monitoring base 22 installed on the shunt passage 11, the monitoring base 22 is provided with an upstream interface 221 and a downstream interface 222, the upstream interface 221 and the downstream interface 222 are communicated through a monitoring pipeline, the monitoring pipeline is installed with a flow sensor (not shown), and the flow sensor (not shown) is electrically connected with the signal processing module.

[0061] In one of the embodiments, the shunt passage 11 comprises a first passage 111 and a second passage 112 separated by a separation part 115, the first passage 111 is communicated with the upstream interface 221 through a first branch 113, and the second passage 112 is communicated with the downstream interface 222 through a second branch 114.

[0062] In one of the embodiments, the flow limiting passage 12 comprises an upstream passage 121 and a downstream passage 122 separated by the flow limiting assembly 3, the upstream passage 121 is communicated with the second passage 112, the flow limiting assembly 3 abuts at the outlet of the upstream passage 121, and the downstream passage 122 is communicated with the limiting groove 51;

[0063] The flow limiting assembly 3 comprises a first magnetic block 31 fixedly installed on the top of the limiting groove 51 and a second magnetic block 32 movably connected in the limiting groove 51, the bottom of the second magnetic block 32 movably connected with a magnetic conducting block 33, a branch block 34 is arranged in the upstream passage 121, a flow limiting branch 35 is arranged in the branch block 34, the magnetic conducting block 33 is located at the outlet of the flow limiting branch 35 and abuts against the branch block 34 with a preset opening degree, and the preset opening degree is a flow gap formed between the magnetic conducting block 33 and the branch block 34.

[0064] In one embodiment, an elastic member (not shown) is further arranged between the second magnetic block 32 and the magnetic conducting block 33, and the elastic member (not shown) is used to provide elastic force for resetting the magnetic conducting block 33 and abutting against the branch block 34 with the preset opening degree when the coil (not shown) is powered off, and to assist in stabilizing the flow limiting stroke of the magnetic conducting block 33 when pressure fluctuation occurs.

[0065] It should be noted that in actual use, the monitoring base 22 is integrated on the outer surface of the shunt passage 11 through mechanical connection, the upstream interface 221 is communicated with the high-pressure side of the shunt passage 11 through the first branch 113, the downstream interface 222 is communicated with the low-pressure side of the shunt passage 11 through the second branch 114, when the medium flows through the shunt passage 11, part of the medium enters the monitoring pipeline through the first branch 113, flows through the flow sensor (not shown) and returns to the shunt passage 11 through the second branch 114, the flow sensor (not shown) calculates the flow value by measuring the temperature change of the flowing medium and directly transmits the electric signal to the signal processing module; the independent arrangement of the monitoring pipeline can isolate the flow detection process from the pressure fluctuation of the main passage, so as to avoid the influence of pressure fluctuation on the measurement accuracy of the sensor.

[0066] It should be additionally noted that in actual use, the first passage 111 and the second passage 112 are formed by arranging the separation part 115 inside the shunt passage 11 to be physically isolated, so that the pressure detection and the flow detection are respectively completed in the independent flow channels, the pressure sensor 21 can directly obtain the inlet pressure value of the inlet which is not disturbed by the downstream pressure fluctuation in the first passage 111, and the monitoring pipeline is connected to the downstream interface 222 to form a closed loop detection circuit through the second branch 114, so that the flow sensor (not shown) can measure the medium flow after the adjustment of the shunt passage 11 through the circuit, since the first passage 111 and the second passage 112 are completely isolated by the separation part 115, the upstream pressure fluctuation only acts on the first passage 111, and the flow detection process is independently carried out in the monitoring pipeline, so that the pressure fluctuation can be prevented from being transmitted to the area where the flow sensor (not shown) is located through the common flow channel.

[0067] It should be noted that the flow limiting component 3 refers to a linkage mechanism composed of magnetic elements and magnetic conductive components, which can specifically adopt a neodymium iron boron permanent magnet as the first magnetic block 31 and a soft magnetic alloy material as the second magnetic block 32 to realize displacement transmission through the attractive force or repulsive force between the magnetic poles; the branch stop block 34 refers to a flow limiting structure arranged in the upstream passage 121, which can specifically adopt a corrosion-resistant metal to be processed into a component with a tapered through hole, and the contact area between the magnetic conductive block 33 and the edge of the tapered through hole is changed to adjust the medium flow; the flow limiting branch 35 refers to a fluid passage penetrating through the branch stop block 34, which can specifically adopt a precision drill hole with a diameter of 0.5-2 mm to realize; the magnetic conductive block 33 refers to a flow limiting execution component with magnetic response characteristics, which can specifically be made of iron-nickel alloy;

[0068] The elastic member (not shown) refers to a mechanical structure with elastic deformation capability, which can specifically be implemented by using a coil spring, a disc spring or an elastic gasket, and the elastic force parameters can be matched and designed according to the pressure fluctuation range, which is used to drive the magnetic conductive block 33 to reset in the power-off state and to absorb mechanical impact energy through deformation when the pressure fluctuates; the movable connection of the magnetic conductive block 33 is to form a movable contact relationship between the magnetic conductive block 33 and the outlet of the flow limiting branch 35, which can specifically be implemented by using a sliding guide rail or a low-friction bearing, and is used to adjust the opening of the flow limiting branch 35 under the joint action of electromagnetic drive and elastic force of the elastic member (not shown), i.e., to control the flow limiting stroke; the branch stop block 34 refers to a limiting structure fixed in the flow limiting passage 12, which can specifically be provided with a stepped through hole or an annular groove to form a sealing contact surface with the magnetic conductive block 33 and to limit the leakage of the medium in the non-working state;

[0069] Specifically, the upstream passage 121 and the second passage 112 form a medium conveying channel, when the pressure fluctuation causes the pressure in the upstream passage 121 to abnormally rise, the medium impact force acts on the branch stop block 34, at this time the signal processing module outputs corresponding control signals to the control module, so that the coil (not shown) is energized according to the predetermined current direction and generates a magnetic field, at this time the fixedly installed first magnetic block 31 and the movable second magnetic block 32 form a closed magnetic circuit, the second magnetic block 32 is displaced upward under the action of the reverse magnetic field generated by the driving module, the magnetic conductive block 33 is separated from the outlet of the flow limiting branch 35 of the branch stop block 34, the elastic member (not shown) is compressed and stores energy in the displacement process of the second magnetic block 32, at the same time, the opening of the flow limiting branch 35 is increased to make the excess medium quickly flow to the downstream passage 122; when the pressure recovers to be stable, the elastic member (not shown) releases the stored energy to push the magnetic conductive block 33 to reset, and the magnetic conductive block 33 re-establishes the preset opening abutment with the branch stop block 34; in this process, the axial displacement amount of the magnetic conductive block 33 is accurately controlled through the dynamic balance of the magnetic force and the elastic force, so that the opening adjustment of the flow limiting branch 35 can not only offset the influence of pressure fluctuation, but also maintain the set value of the medium flow;

[0070] When the coil (not shown) is powered off, the elastic force of the elastic member (not shown) pushes the magnetic conducting block 33 to move towards the branch stop block 34, until the two maintain a preset opening, at which time the current limiting branch 35 is at the minimum safe opening; when pressure fluctuation occurs in the passage, the medium pressure acts on the surface of the magnetic conducting block 33, causing it to displace, at which time the elastic member (not shown) offsets the impact force generated by the pressure fluctuation by compression or stretching deformation, maintaining the positional stability of the magnetic conducting block 33; during electromagnetic driving, the magnetic field force generated by the coil (not shown) and the elastic force of the elastic member (not shown) form a dynamic balance, and when the pressure fluctuation causes the magnetic conducting block 33 to deviate from the target position, the deformation amount of the elastic member (not shown) changes to generate a reverse force, assisting the electromagnetic drive to quickly correct the current limiting stroke of the magnetic conducting block 33.

[0071] In this embodiment, the first passage 111 and the second passage 112 are formed by the partition 115, which can limit pressure fluctuations in the first passage 111 and maintain a stable flow detection environment in the monitoring passage and the second passage 112, avoiding cross interference of pressure fluctuations on flow measurement; the two-stage current limiting structure formed by the branch stop block 34 and the magnetic conducting block 33 can disperse the pressure fluctuation energy to the current limiting branch 35 for discharge, thereby avoiding the flow fluctuation in the main passage assembly 1; the mechanical buffering characteristics of the elastic member (not shown) can convert the pressure fluctuation energy into elastic potential energy to reduce the displacement deviation of the magnetic conducting block 33, and the reset function of the elastic member (not shown) can eliminate the risk of valve failure caused by the disappearance of the magnetic field in the powered-off state.

[0072] One embodiment of the present application also provides a thermal mass flow control method with pressure compensation, which applies the thermal mass flow controller with pressure compensation as described above, and includes the following steps:

[0073] S1: Obtain the pressure value at the inlet of the shunt passage 11 through the pressure sensor 21, and obtain the flow value of the medium in the shunt passage 11 through the flow sensor (not shown);

[0074] S2: Receive the pressure value through the pressure compensation submodule of the signal processing module, calculate the pressure fluctuation amount, and generate a compensation signal in combination with the elastic force parameter of the elastic member (not shown);

[0075] S3: Receive the compensation signal through the driving module, adjust the current of the coil (not shown) according to the compensation signal, to balance the influence of pressure fluctuation on the current limiting stroke of the magnetic conducting block 33, and realize preliminary control of the medium flow in the current limiting passage 12.

[0076] It should be noted that the pressure sensor 21 refers to a device for detecting the pressure of the medium at the inlet of the shunt passage 11, which can be realized by a piezoelectric or capacitive sensor, and its function is to sense the change of the inlet pressure in real time and provide raw data for pressure compensation; the flow sensor (not shown) refers to a device for measuring the flow of the medium in the shunt passage 11, which can be realized by a thermal or ultrasonic sensor, and its function is to monitor the flow change synchronously and provide a feedback signal for closed-loop control; the pressure compensation sub-module refers to the algorithm unit embedded in the signal processing module, which can be realized by a digital signal processor or a microcontroller, and its function is to combine the pressure fluctuation with the mechanical parameters of the elastic element (not shown) to generate a control signal with feedforward compensation function; the elastic force parameter of the elastic element (not shown) refers to the restoring force characteristic generated by the spring or elastomer during deformation, which can be represented by a pre-set stiffness coefficient or experimental calibration data, and its function is to provide a reverse correction reference for the mechanical displacement caused by pressure fluctuation; the driving module refers to the power output unit for controlling the current of the coil (not shown), which can be realized by an H-bridge circuit or a PWM modulation circuit, and its function is to receive the compensation signal output by the signal processing module and convert it into an adjustable current signal to control the current flowing through the coil (not shown) and generate an electromagnetic field to drive the magnetic block 33 to adjust the flow limiting stroke; the coil (not shown) current refers to the current intensity flowing through the electromagnetic coil (not shown), which can be controlled by adjusting the voltage or duty cycle, and its function is to change the position of the magnetic block by changing the magnetic field, thereby offsetting the influence of pressure fluctuation on the flow limiting component 3.

[0077] Specifically, the pressure sensor 21 is arranged at the inlet of the shunt passage 11, which can capture the change of the medium pressure in real time. Taking the sudden increase of the pressure at the inlet of the shunt passage 11 as an example, the pressure sensor 21 will transmit the fluctuation signal to the signal processing module, the pressure compensation sub-module in the signal processing module will quantitatively calculate the pressure fluctuation, and combine the pre-set stiffness parameter of the elastic element (not shown) to generate a compensation signal containing the dynamic response of the mechanical system. After the compensation signal is received by the driving module, the driving module will adjust the intensity and direction of the coil (not shown) current to change the attractive force or repulsive force of the electromagnetic field on the magnetic block, when the pressure increases suddenly and causes the displacement of the magnetic block 33, the driving module increases the coil (not shown) current to enhance the reverse magnetic field, forcing the magnetic block 33 to return to the pre-set position, thereby maintaining the flow stability of the flow limiting passage 12.

[0078] In this embodiment, through the cooperative monitoring of the pressure sensor 21 and the flow sensor (not shown), combined with the dynamic compensation of the elastic force parameters of the elastic member (not shown) to the pressure fluctuation, the position of the magnetic conducting block 33 can be corrected in the reverse direction through electromagnetic driving at the moment of pressure mutation, thereby suppressing the interference of the pressure fluctuation on the flow limiting stroke, avoiding the abnormal displacement of the magnetic conducting block 33 caused by the change of the medium thrust, and maintaining the stability of the flow of the flow limiting passage 12. In addition, through the combination of feedforward compensation and closed-loop regulation, the driving current can be adapted to the pressure fluctuation and the flow deviation at the same time, thereby improving the overall dynamic response speed and control accuracy.

[0079] In one embodiment, after step S3, further comprising:

[0080] S4: receiving the flow value through the closed-loop regulation submodule of the signal processing module, and comparing the deviation of the flow value from the target flow;

[0081] S5: correcting the compensation signal output by the pressure compensation submodule according to the deviation through the closed-loop regulation submodule, so that the current output by the driving module is adapted to the deviation and the pressure fluctuation;

[0082] S6: adjusting the current of the coil (not shown) through the driving module according to the corrected compensation signal, accurately controlling the flow limiting stroke of the magnetic conducting block 33, and realizing closed-loop control of the medium flow in the flow limiting passage 12.

[0083] It should be noted that the closed-loop regulation submodule refers to a feedback control unit for receiving the measured data of the flow sensor (not shown) and dynamically comparing it with the preset target flow. Specifically, it can be realized by using an embedded PID controller combined with a deviation operation circuit. Its function is to convert the flow deviation into a correction parameter of the compensation signal. Wherein, the compensation signal correction refers to the operation process of superimposing or proportionally fusing the initial compensation signal output by the pressure compensation submodule and the flow deviation. Specifically, it can be realized by using the weighting algorithm module in the digital signal processor. Its function is to make the driving current contain the double regulation parameters of pressure fluctuation compensation and flow deviation correction. Wherein, the double adaptation refers to the fact that the current value output by the driving module needs to match the compensation demand caused by the pressure fluctuation and the correction demand caused by the flow deviation at the same time. Specifically, it can be realized by using a multivariable feedback control model combined with a current modulation circuit. Its function is to ensure that the flow limiting stroke of the magnetic conducting block 33 can respond to both the pressure change and the flow deviation.

[0084] Specifically, after the initial pressure compensation control is completed, the flow sensor (not shown) continuously collects the real-time flow value in the shunt passage 11 and transmits it to the closed-loop adjustment submodule. The closed-loop adjustment submodule compares the real-time flow value with the preset target flow, calculates the positive or negative deviation, and generates a correction coefficient through proportional integral operation, which acts on the initial compensation signal output by the pressure compensation submodule to form a superimposed comprehensive compensation signal. After the driving module receives the comprehensive compensation signal, it adjusts the amplitude and direction of the coil (not shown) current according to the pressure fluctuation compensation parameters and flow deviation correction parameters contained therein. The magnetic field generated by the change of the coil (not shown) current acts on the magnetic conductive block 33, causing its flow limiting stroke to offset the influence of pressure fluctuation and eliminate flow accumulation deviation, and finally achieving closed-loop stable control of the medium flow in the flow limiting passage 12.

[0085] In this embodiment, the pressure fluctuation and flow deviation are cooperatively offset by double signal adaptation. When the pressure in the shunt passage 11 suddenly changes, the closed-loop adjustment mechanism can quickly identify the flow deviation and correct the compensation signal, and then accurately control the action of the driving module according to the corrected compensation signal, avoiding over-adjustment or response lag of the magnetic conductive block 33 caused by pressure impact, and ensuring that the medium flow in the flow limiting passage 12 is stable within the target set range.

[0086] In one embodiment, in step S2, further comprising:

[0087] S21: receiving the pressure value by the dynamic response submodule of the signal processing module, and analyzing the change rate of the pressure value;

[0088] S22: setting the current adjustment gradient of the coil (not shown) by the dynamic response submodule according to the change rate of the pressure value;

[0089] S23: adjusting the current of the coil (not shown) by the driving module according to the current adjustment gradient, so that the action speed of the magnetic conductive block 33 matches the change rate of the pressure value.

[0090] It should be noted that the dynamic response submodule refers to an operation unit for real-time analysis of pressure data change trend, which can be realized by a microprocessor combined with a differential algorithm, and is used for capturing the dynamic characteristics of pressure fluctuation; wherein the change rate of the pressure value refers to the amplitude of pressure change per unit time, which can be obtained by calculating the first derivative of the continuous sampling data of the pressure sensor 21, and is used to represent the severity of pressure fluctuation; wherein the current adjustment gradient refers to the step setting value of the driving current change, which can be realized by a preset gradient mapping table, and the corresponding current adjustment amplitude is matched according to different intervals of the pressure change rate; wherein the action speed of the magnetic conducting block 33 refers to the response rate of the displacement of the magnetic conducting block 33 in the flow limiting component 3, which can be realized by the dynamic balance of the magnetic field strength of the coil (not shown) and the reaction force of the elastic member (not shown), and is used to adjust the medium flow of the flow limiting passage 12.

[0091] Specifically, after receiving the continuous sampling data of the pressure sensor 21, the dynamic response submodule can calculate the change rate of the pressure value in real time through differential operation, and the change rate is divided into multiple intervals, such as a pressure sudden change interval and a slow change interval, each interval corresponds to a different current adjustment gradient. When the pressure change rate is in the sudden change interval, the dynamic response submodule calls a large gradient parameter, the driving module adjusts the magnetic field strength of the coil (not shown) with a large current step to make the magnetic conducting block 33 produce rapid displacement to offset the flow disturbance caused by the pressure sudden change. When the pressure change rate is in the slow change interval, the dynamic response submodule calls a small gradient parameter, the driving module adjusts the magnetic field strength with a fine current step to make the magnetic conducting block 33 follow the pressure fluctuation trend at a gentle speed. Through the gradient current adjustment mechanism, the action speed of the magnetic conducting block 33 dynamically matches the pressure fluctuation rate. When the pressure fluctuates rapidly, the large gradient current adjustment is used to quickly stabilize the flow. When the pressure changes slowly, the small gradient current adjustment is used to finely control the flow.

[0092] In this embodiment, by introducing the pressure change rate analysis mechanism, the correlation between the pressure fluctuation trend and the valve response speed is established, so that the magnetic conducting block 33 adopts differentiated action speed under different pressure fluctuation scenarios, thereby effectively eliminating the flow overshoot caused by pressure sudden change or the regulation lag caused by slow change.

[0093] The complete working principle of the application will be described below taking the rapid abnormal rise of the pressure at the inlet of the shunt passage as an example.

[0094] In the initial state, the application is in a stable working state, the medium in the shunt passage 11 is transported at a preset flow rate, in the flow limiting passage 12, the upstream passage 121 is in communication with the second passage 112, the magnetic conducting block 33 is in a preset flow limiting stroke under the action of the elastic member (not shown), and is in abutment with the branch block 34 at a preset opening, the pressure sensor 21 and the flow sensor (not shown) of the monitoring assembly 2 continuously collect the pressure value and the flow value of the shunt passage 11, and the signal processing module in the control assembly continuously operates, wherein the pressure compensation submodule continuously generates a compensation signal for maintaining the magnetic conducting block 33 at a position corresponding to the preset flow limiting stroke based on the current pressure value and the parameters of the elastic member (not shown), and the closed-loop adjustment submodule continuously compares the real-time flow with the preset flow, and if there is a slight deviation, the compensation signal is immediately corrected to allow the magnetic conducting block 33 to slightly displace back to the position corresponding to the preset flow limiting stroke through a slight change in the magnetic field force;

[0095] When the pressure at the inlet of the shunt passage 11 rapidly and abnormally rises, the pressure sensor 21 in the first passage 111 captures the situation of the sudden rise in pressure in real time and continuously calculates the pressure fluctuation amount, and transmits the pressure fluctuation signal to the signal processing module in the main control housing 4 in real time; synchronously, the dynamic response submodule of the signal processing module synchronously receives the continuous sampling data of the pressure sensor 21, calculates the change rate of the pressure value in real time through differential operation, compares the preset pressure change rate interval, determines that the current pressure is in the preset sudden change interval range, immediately calls the preset large gradient current adjustment parameter, and directly transmits the gradient parameter to the pressure compensation submodule; and the flow rate of the medium in the shunt passage 11 increases under the action of the suddenly rising pressure, part of the medium in the second passage 112 enters the monitoring pipeline through the first branch 113, and when flowing through the flow sensor (not shown), the sensor detects the real-time flow value by measuring the temperature change of the medium, and synchronously transmits the real-time flow value to the signal processing module;

[0096] After the signal processing module receives the data of the pressure fluctuation amount and the real-time flow value, the pressure compensation submodule cooperates to calculate the compensation current through a preset algorithm based on the pressure fluctuation amount and the elastic force parameters of the elastic member (not shown):

[0097]

[0098] Wherein is the force area of the magnetic conducting block, is the initial elastic force, is the magnetic field force generated by each ampere of current, is the pressure fluctuation amount; and by the pressure thrust on the magnetic conducting block can be calculated, since the magnetic field needs to overcome the pressure thrust on the magnetic conducting block together with the initial elastic force to displace the magnetic conducting block upward, therefore, the relationship formula between the magnetic field force and the current is combined wherein is the magnetic field force generated by the coil after energization, is the compensation current of the coil, is the electromagnetic conversion coefficient of the coil, The physical meaning of "1 Newton of magnetic field force generated by the coil per 1 Ampere of current" can be obtained to derive the calculation formula of the compensation current. The pressure compensation sub-module generates an initial compensation signal corresponding to the compensation current and transmits it to the driving module.

[0099] The driving module receives the initial compensation signal and quickly adjusts the current of the coil (not shown) through the H-bridge circuit on the circuit board. The coil (not shown) generates a magnetic field after energization, and the magnetic field acts on the current limiting component 3. At this time, the first magnetic block 31 fixed at the top of the limiting groove 51 and the second magnetic block 32 form a repulsive force, which pushes the second magnetic block 32 to displace axially upward along the limiting groove 51. When the second magnetic block 32 displaces upward, the bottom-connected magnetic conductive block 33 is synchronously separated from the branch block 34, to the adjusted current limiting stroke, the opening degree of the current limiting branch 35 increases, and the elastic member (not shown) is compressed, completing energy storage. After the opening degree increases, the excess medium generated by the sudden rise in pressure in the upstream passage 121 is quickly discharged to the downstream passage 122 through the current limiting branch 35, and the flow of the shunt passage 11 gradually decreases, preliminarily offsetting the influence of pressure fluctuation.

[0100] Synchronously, the flow sensor (not shown) continuously collects the flow data of the shunt passage 11 and transmits it to the closed-loop adjustment sub-module. The closed-loop adjustment sub-module compares the preset flow and the flow data of the shunt passage 11 and calculates the current deviation. The closed-loop adjustment sub-module generates a correction coefficient through a PID algorithm, corrects the initial compensation signal, generates a correction compensation signal corresponding to the preset limiting stroke of the magnetic conductive block 33, and transmits it to the driving module.

[0101] The driving module receives the correction compensation signal and quickly adjusts the current of the coil (not shown) through the H-bridge circuit on the circuit board, adjusting the current of the coil (not shown) to the correction compensation current value corresponding to the correction compensation signal. After the current of the coil (not shown) is corrected, the magnetic field force decreases, and the elastic member (not shown) pushes the second magnetic block 32 and the magnetic conductive block 33 to slightly displace downward, and the opening degree of the current limiting branch 35 is reduced to the initial preset position. At this time, the medium discharge flow is reduced, and the main flow of the shunt passage 11 restores to the preset flow.

[0102] When the pressure at the inlet of the shunt passage 11 recovers, the application restores the initial state.

[0103] Advantages:

[0104] This invention achieves precise compensation and rapid response to pressure fluctuations by setting pressure sensor 21 and flow sensor (not shown) to synchronously collect pressure and flow values ​​of diversion path 11. The control component combines the pressure fluctuation amount with the elastic force parameter of elastic element (not shown) to generate a compensation signal. With the help of dynamic response submodule, the current adjustment gradient is set according to the pressure change rate, which drives the current limiting component 3 to adjust the current limiting stroke of magnetic block 33. This reduces the interference of pressure fluctuation in diversion path 11 on the medium flow of limiting path 12, shortens the pressure compensation response time, avoids flow overshoot, undershoot and lag problems, and keeps the medium flow stable within the target set range.

[0105] The present invention also integrates the signal processing module and monitoring component 2 into the main control housing 4 and independently sets the drive module in the drive housing 5 through the partitioned design of the main control housing 4 and the drive housing 5. This provides a dustproof and anti-interference protection space for the signal processing module, avoids the electromagnetic interference generated when the coil (not shown) is working from affecting the acquisition accuracy of pressure and flow signals, and further improves the accuracy of flow control. In addition, by setting a partition 115 in the branch flow path 11 to form an independent first path 111 and a second path 112, the pressure detection and flow detection are completed in physically isolated flow channels, preventing upstream pressure fluctuations from being transmitted to the area where the flow sensor (not shown) is located through the common flow channel, and ensuring the stability and accuracy of flow measurement data.

[0106] The present invention also achieves automatic reset of the magnetic block 33 when the coil (not shown) is de-energized by the coordinated cooperation of the elastic element (not shown) and the electromagnetic drive, so that the current limiting branch 35 maintains the minimum safe opening and avoids the risk of process interruption caused by the interruption of medium flow after power failure; in addition, when the pressure fluctuates, the elastic element (not shown) can absorb the mechanical impact energy through deformation, help stabilize the current limiting stroke of the magnetic block 33, reduce the displacement deviation of the magnetic block 33 caused by sudden pressure changes, and improve the safety and stability of equipment operation;

[0107] The control method of this invention forms a standardized flow control logic by executing pressure acquisition, compensation signal generation, current gradient adjustment, and closed-loop correction in steps. This facilitates the integration of core components through a dedicated control circuit board, thereby reducing the hardware design complexity and production cost of the equipment. In addition, the overall automated control is achieved through preset regulation rules and algorithm programs, reducing manual intervention and improving the stability and reliability of equipment operation.

[0108] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A thermal mass flow controller with pressure compensation, characterized in that, It includes a main path component, a monitoring component, a current limiting component, and a control component. The main path component includes a branch path connected to the monitoring component and a current limiting path connected to the current limiting component. The control component is electrically connected to the monitoring component and the current limiting component. The monitoring component also includes a pressure sensor installed at the air inlet of the diversion path. The pressure sensor is used to acquire the pressure value of the diversion path and transmit it to the control component. It also includes a main control housing installed on the diversion path and a drive housing installed outside the current limiting component. The control component includes a signal processing module and a drive module. The signal processing module and the monitoring component are installed in the main control housing, and the drive module is installed in the drive housing to avoid electromagnetic interference generated when the drive module is working from affecting the acquisition accuracy of pressure and flow signals. The diversion path includes a first path and a second path separated by a partition. The first path is used to cooperate with a pressure sensor to collect pressure values, and the second path is used to cooperate with a flow sensor to collect flow values, so that pressure detection and flow detection are completed in physically isolated flow channels, preventing upstream pressure fluctuations from being transmitted to the area where the flow sensor is located through a shared flow channel. The monitoring component is used to acquire the flow rate and pressure value of the medium in the diversion path in real time and transmit them to the control component; the control component is used to acquire the flow rate and pressure value, and control the current limiting stroke of the current limiting component according to the flow rate and pressure value; the current limiting component is used to limit the flow rate of the medium in the diversion path; specifically, the pressure value is received by the dynamic response submodule of the signal processing module, and the rate of change of the pressure value is analyzed; the current adjustment gradient of the coil is set by the dynamic response submodule according to the rate of change of the pressure value; the current of the coil is adjusted by the drive module according to the current adjustment gradient, so that the action speed of the magnetic block matches the rate of change of the pressure value; The drive module receives a compensation signal and adjusts the current of the coil according to the compensation signal to balance the influence of pressure fluctuations on the current-limiting stroke of the magnetic block, thereby achieving preliminary control of the medium flow rate in the current-limiting path.

2. The thermal mass flow controller with pressure compensation according to claim 1, characterized in that, The signal processing module is used to control the forward or reverse current of the drive module according to the flow rate and the pressure value. The drive module is used to generate a positive or reverse magnetic field according to the forward or reverse current to control the current limiting stroke of the current limiting component.

3. A thermal mass flow controller with pressure compensation according to claim 2, characterized in that, The drive housing includes a limiting groove for mounting the current limiting component and an annular cavity surrounding the limiting groove. The current limiting component is movably mounted in the limiting groove. The drive module includes a coil wound in the annular cavity.

4. A thermal mass flow controller with pressure compensation according to claim 3, characterized in that, The monitoring component includes a monitoring base installed on the distribution channel. The monitoring base has an upstream interface and a downstream interface, which are connected by a monitoring pipeline. A flow sensor is installed on the monitoring pipeline and is electrically connected to the signal processing module.

5. A thermal mass flow controller with pressure compensation according to claim 3, characterized in that, The flow-limiting path includes an upstream path and a downstream path separated by a flow-limiting component. The upstream path is connected to the second path. The flow-limiting component abuts against the outlet of the upstream path. The downstream path is connected to the limiting groove. The current limiting component includes a first magnetic block fixedly installed on the top of the limiting groove and a second magnetic block movably connected in the limiting groove. A magnetic guide block is movably connected to the bottom of the second magnetic block. A branch block is provided in the upstream passage. A current limiting branch is opened in the branch block. The magnetic guide block is located at the outlet of the current limiting branch and abuts against the branch block at a preset opening degree. The preset opening degree is the flow gap formed between the magnetic guide block and the branch block.

6. A thermal mass flow controller with pressure compensation according to claim 5, characterized in that, An elastic element is also provided between the second magnetic block and the magnetically conductive block. The elastic element is used to provide a spring force to reset the magnetically conductive block and maintain the preset opening against the branch block when the coil is de-energized, and to help stabilize the current-limiting stroke of the magnetically conductive block when pressure fluctuations occur.

7. A method for controlling thermal mass flow with pressure compensation, applied to the thermal mass flow controller with pressure compensation as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Obtain the pressure value at the air inlet of the diversion channel through the pressure sensor, and obtain the flow rate value of the medium in the diversion channel through the flow sensor; S2: The pressure value is received by the pressure compensation submodule of the signal processing module, the pressure fluctuation is calculated, and a compensation signal is generated in combination with the elastic force parameters of the elastic element, including: S21: The pressure value is received by the dynamic response submodule of the signal processing module, and the rate of change of the pressure value is analyzed; S22: The current adjustment gradient of the coil is set by the dynamic response submodule according to the rate of change of the pressure value; S23: The current of the coil is adjusted by the drive module according to the current adjustment gradient, so that the action speed of the magnetic block matches the rate of change of the pressure value. S3: Receive the compensation signal through the drive module, and adjust the current of the coil according to the compensation signal to balance the influence of pressure fluctuation on the current limiting stroke of the magnetic block, thereby achieving preliminary control of the medium flow in the current limiting path.

8. The thermal mass flow control method with pressure compensation according to claim 7, characterized in that, Following step S3, the following is also included: S4: Receive the flow rate value through the closed-loop adjustment submodule of the signal processing module, and compare the deviation of the flow rate value with the target flow rate; S5: The closed-loop adjustment submodule corrects the compensation signal output by the pressure compensation submodule according to the deviation, so that the current output by the drive module is doubly adapted to the deviation and the pressure fluctuation. S6: The drive module adjusts the current of the coil according to the corrected compensation signal to precisely control the current-limiting stroke of the magnetic block, thereby achieving closed-loop control of the medium flow rate in the current-limiting path.

Images