Mass flow controller

Abstract

The invention discloses a mass flow controller which comprises a Y-shaped pipe body, a flow sensor and an adjusting valve, the Y-shaped pipe body comprises a first pipeline, a second pipeline used for inputting fluid and a third pipeline used for outputting fluid, and the detection end of the flow sensor is located in the second pipeline; the adjusting valve comprises a valve cage fixedly connected into the first pipeline, a valve cage cover covering the valve cage, a valve element connected into the valve cage in a sliding mode, a push rod rotationally connected to the valve cage cover and a rotation driving mechanism fixedly connected to the valve cage cover, and the rotation driving mechanism is connected with the push rod through a worm and gear speed reducer. The push rod is connected with the valve element through a lead screw structure. The end of the valve cage is provided with a flow channel used for communicating the second pipeline with the third pipeline. The flow sensor and the rotation driving mechanism are electrically connected with a control module. According to the mass flow controller, a fluid flowing channel with higher liquidity and streamline can be formed so as to reduce fluid noise under the high-flow-speed application working condition, and the size of the mass flow controller can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid mass flow measurement and control, and in particular relates to a mass flow controller. Background Art

[0002] A mass flow controller is a device used to accurately measure and control the mass flow of gas or liquid. It not only has the function of a mass flow meter, but more importantly, it can automatically control the gas flow rate and keep the flow rate at the set value even if the system pressure fluctuates or the ambient temperature changes.

[0003] The application scenarios of mass flow controllers include electronic process equipment for diffusion, oxidation, molecular beam epitaxy, CVD, plasma etching, sputtering and ion implantation, as well as vacuum coating equipment, optical fiber melting equipment, micro-reaction devices, gas mixing and distribution systems and capillary measurement gas chromatographs.

[0004] Among them, the mass flow controller usually includes a tube body and a regulating valve vertically arranged on the tube body. The flow path of the fluid near the regulating valve is generally S-shaped, and its flow direction varies greatly, which makes the fluid noise larger under high flow rate application conditions; in addition, the regulating valve is distributed in a direction perpendicular to the tube body, and the space it occupies in this direction is larger, which makes the mass flow controller occupy a larger space in the direction perpendicular to the tube body. Summary of the invention

[0005] In order to overcome the defects of the prior art, the present invention provides a mass flow controller capable of reducing fluid noise and volume.

[0006] The object of the present invention is achieved through the following technical solutions: A mass flow controller comprising: A Y-shaped tube body, the Y-shaped tube body comprising a first pipe, a second pipe for inputting fluid, and a third pipe for outputting fluid; A flow sensor, wherein a detection end of the flow sensor is located in the second pipeline; A regulating valve, the regulating valve comprises a valve cage fixedly connected in a first pipeline, a valve cage cover arranged on the valve cage, a valve core slidably connected in the valve cage, a push rod rotatably connected to the valve cage cover, and a rotation driving mechanism fixedly connected to the valve cage cover, the axis of the valve cage, the axis of the valve core and the axis of the push rod all coincide with the axis of the first pipeline, the rotation center line of the rotation driving mechanism is perpendicular to the axis of the first pipeline, the rotation driving mechanism is connected to the push rod through a worm gear reducer, the push rod is connected to the valve core through a screw structure, and a flow channel for connecting the second pipeline and the third pipeline is provided at the end of the valve cage, wherein when the rotation driving mechanism is in operation, the valve core gradually adjusts the opening of the flow channel; A control module is electrically connected to the flow sensor and the rotation drive mechanism.

[0007] The beneficial effects of adopting the above technical solution are as follows: in the Y-shaped tube body, the second pipe, the flow channel and the third pipe can form a fluid flow channel with better fluidity and streamline, so as to reduce the fluid noise under high flow rate application conditions; at the same time, the first pipe is inclined toward the main fluid flow pipes such as the second pipe or the third pipe, that is, the regulating valve is closer to the main fluid flow pipe, so that the mass flow controller occupies less space in the direction perpendicular to the main fluid flow pipe, thereby making the components on the mass flow controller more concentrated; in addition, the rotation drive mechanism only drives the push rod to rotate, and then drives the valve core to adjust the opening of the flow channel through the screw structure, without driving the push rod to move axially, which further avoids occupying additional space in the direction perpendicular to the main fluid flow pipe, and because the worm gear reducer can amplify the torque, the power of the rotation drive mechanism is related to its own volume, so a smaller rotation drive mechanism can be selected here, which is beneficial to reduce the volume of the mass flow controller.

[0008] Furthermore, the control module and the flow sensor are both fixedly connected to the second pipeline and on the same side as the regulating valve.

[0009] The beneficial effect of adopting the above technical solution is that the control module, flow sensor, regulating valve and other components on the mass flow controller are arranged more centrally to facilitate installation and packaging.

[0010] Furthermore, the mass flow controller comprises a stainless steel housing for encapsulating the control module, the flow sensor and the regulating valve on the Y-shaped tube body.

[0011] The beneficial effect of adopting the above technical solution is that the stainless steel shell can centrally package the control module, flow sensor and regulating valve on the Y-shaped tube body to improve the explosion-proof performance of the mass flow controller and enable the mass flow controller to be used in explosion-proof places.

[0012] Furthermore, a display screen is arranged on the control module, and a tempered glass window is arranged on the stainless steel housing, and the position of the tempered glass window matches the position of the display screen.

[0013] The beneficial effects of adopting the above technical solution are: the relevant parameters of the mass flow controller can be displayed on the display screen, that is, the relevant parameters of the mass flow controller can be viewed through the tempered glass window, and the parameters can be conveniently set using an infrared hand operator; in addition, the tempered glass window can also meet explosion-proof requirements.

[0014] Furthermore, the flow sensor is a thermal flow sensor.

[0015] The beneficial effects of adopting the above technical solution are: the thermal flow sensor has a wider measurement range and higher measurement accuracy, so that the mass flow controller can collect data more accurately.

[0016] Furthermore, the rotation driving mechanism is a stepping motor.

[0017] The beneficial effect of adopting the above technical solution is that the stepper motor can accurately control the rotation angle, which is conducive to accurately controlling the opening of the flow channel through the valve core, so that the mass flow controller can be executed more accurately.

[0018] Furthermore, the worm gear reducer comprises a worm wheel and a worm that mesh with each other, the worm is coaxially fixedly connected to the output end of the rotation drive mechanism, and the worm wheel is coaxially fixedly connected to the push rod.

[0019] The beneficial effect of adopting the above technical solution is that the rotary drive mechanism drives the worm to rotate, thereby driving the worm wheel meshing with the worm to rotate, thereby driving the push rod to rotate.

[0020] Furthermore, the push rod is rotatably connected to the valve cage cover via a bearing, and a bearing cover for axially limiting the bearing is fixedly connected to the valve cage cover.

[0021] The beneficial effect of adopting the above technical solution is that the push rod can be arranged in this way so as to rotate more smoothly on the valve cage cover by means of the bearing, and the bearing cover can limit the bearing axially on the valve cage cover.

[0022] Furthermore, the screw structure includes a screw nut clamped in the valve core and an external thread arranged at one end of the push rod, and the external thread matches the internal thread of the screw nut; a nut cover for axially limiting the screw nut is fixedly connected to the end of the valve core close to the valve cage cover, and a polygonal column is arranged at the end of the nut cover away from the valve core, and a polygonal hole slidably connected to the polygonal column is arranged at the end of the valve cage cover close to the valve core.

[0023] The beneficial effects of adopting the above technical solution are: one end of the push rod with an external thread can be used as a lead screw, and since the lead screw nut is clamped in the valve core, and the valve cage cover can limit the rotation of the valve core by limiting the rotation of the nut cover, when the push rod rotates, the lead screw nut can drive the valve core to slide in the axial direction to adjust the flow channel opening. Furthermore, a first seal is arranged between the flow sensor and the second pipeline; and / or a second seal is arranged between the valve cage and the first pipeline; and / or a third seal is arranged between the valve cage cover and the valve cage; and / or a fourth seal is arranged between the valve core and the valve cage; and / or a fifth seal is arranged between the push rod and the valve cage cover.

[0024] The beneficial effects of adopting the above technical scheme are as follows: the first seal can seal the gap between the flow sensor and the second pipeline to prevent the fluid from leaking outward from the gap between the flow sensor and the second pipeline; the second seal can seal the gap between the valve cage and the first pipeline to prevent the fluid from leaking outward from the gap between the valve cage and the first pipeline; the third seal can seal the gap between the valve cage cover and the valve cage to prevent the fluid from leaking outward through the gap between the valve core and the valve cage and the gap between the valve cage cover and the valve cage in sequence; the fourth seal can seal the gap between the valve core and the valve cage to prevent the fluid from flowing through the gap between the valve core and the valve cage to the gap between the valve cage cover and the valve cage or the gap between the push rod and the valve cage cover; the fifth seal can seal the gap between the push rod and the valve cage cover to prevent the fluid from leaking outward through the gap between the push rod and the valve cage cover; in addition, by adopting these sealing measures, the explosion-proof performance of the mass flow controller can be further improved on the basis of improving the mass flow controller.

[0025] The beneficial effects of the present invention are: In the Y-shaped tube body, the second pipe, the flow channel and the third pipe can form a fluid flow channel with better flow and streamline, so as to reduce the fluid noise under high flow rate application conditions; at the same time, the first pipe is inclined toward the main fluid flow pipes such as the second pipe or the third pipe, that is, the regulating valve is closer to the main fluid flow pipe, so that the mass flow controller occupies less space in the direction perpendicular to the main fluid flow pipe, thereby making the components on the mass flow controller more concentrated; in addition, the rotary drive mechanism only drives the push rod to rotate, and then drives the valve core to adjust the opening of the flow channel through the screw structure, without driving the push rod to move axially, which further avoids occupying additional space in the direction perpendicular to the main fluid flow pipe, and because the worm gear reducer can amplify the torque, the power of the rotary drive mechanism is related to its own volume, so a smaller rotary drive mechanism can be selected here, which is beneficial to reduce the volume of the mass flow controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein: Figure 1 Shows a schematic diagram of the structure of the present invention; Figure 2 Shows Figure 1 A top view of Figure 3 Shows Figure 1 Left view of Figure 4 Shows Figure 3 Sectional view at AA in the middle; Figure 5 A circuit schematic diagram of the circuit board assembly of the present invention is shown; In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0027] Reference numerals: 1-Y-type tube body, 101-first pipeline, 102-second pipeline, 103-third pipeline, 2-stainless steel shell, 3-electrical connector, 4-tempered glass window, 5-flow sensor, 6-valve cage, 7-valve core, 8-screw nut, 9-nut cover, 10-valve cage cover, 11-push rod, 12-bearing, 13-bearing cover, 14-rotation drive mechanism, 15-bracket, 16-worm, 17-worm gear, 18-display screen, 19-first pressure plate, 20-printed circuit board, 21-second pressure plate, 22-first seal, 23-fifth seal, 24-third seal, 25-second seal, 26-fourth seal. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] The present invention provides a mass flow controller, such as Figure 1 and Figure 4 As shown, it includes: A Y-shaped tube body 1, the Y-shaped tube body 1 comprises a first pipe 101, a second pipe 102 for inputting fluid, and a third pipe 103 for outputting fluid; A flow sensor 5, wherein a detection end of the flow sensor 5 is located in the second pipe 102; A regulating valve, the regulating valve comprises a valve cage 6 fixedly connected in a first pipeline 101, a valve cage cover 10 covered on the valve cage 6, a valve core 7 slidably connected in the valve cage 6, a push rod 11 rotatably connected to the valve cage cover 10, and a rotation driving mechanism 14 fixedly connected to the valve cage cover 10, the axis of the valve cage 6, the axis of the valve core 7 and the axis of the push rod 11 all coincide with the axis of the first pipeline 101, the rotation center line of the rotation driving mechanism 14 is perpendicular to the axis of the first pipeline 101, the rotation driving mechanism 14 is connected to the push rod 11 through a worm gear reducer, the push rod 11 is connected to the valve core 7 through a screw structure, and a flow channel for connecting the second pipeline 102 and the third pipeline 103 is provided at the end of the valve cage 6, wherein when the rotation driving mechanism 14 is in operation, the valve core 7 gradually adjusts the opening of the flow channel; A control module is electrically connected to the flow sensor 5 and the rotation drive mechanism 14 .

[0030] It can be understood that, in the Y-shaped tube body 1, the second pipe 102, the flow channel and the third pipe 103 can form a fluid flow channel with better flow and streamline, so as to reduce the fluid noise under high flow rate application conditions; at the same time, the first pipe 101 is inclined toward the main fluid flow pipes such as the second pipe 102 or the third pipe 103, that is, the regulating valve is closer to the main fluid flow pipe, so that the mass flow controller occupies less space in the direction perpendicular to the main fluid flow pipe, thereby making the various components on the mass flow controller more concentrated; in addition, the rotation drive mechanism 14 only drives the push rod 11 to rotate, and then drives the valve core 7 to adjust the opening of the flow channel through the screw structure, without driving the push rod 11 to move axially, which further avoids occupying additional space in the direction perpendicular to the main fluid flow pipe, and because the worm gear reducer can amplify the torque, the power of the rotation drive mechanism 14 is related to its own volume, so a smaller rotation drive mechanism 14 can be selected here, which is conducive to reducing the volume of the mass flow controller.

[0031] It should be noted that the valve cage 6 and the valve cage cover 10 are connected to the first pipe 101 by screws, the valve cage cover 10 is screwed to the bracket 15, and the bracket 15 is screwed to the rotation drive mechanism 14; in addition, the end and end side of the valve cage 6 are provided with holes connected to the internal cavity of the valve cage 6, these holes and the internal cavity of the valve cage 6 together constitute a flow channel, and a sealing ring is installed at the end of the valve cage 6 to close the flow channel when the valve core 7 is pressed against the sealing ring.

[0032] In one embodiment, the control module and the flow sensor 5 are both fixedly connected to the second pipeline 102 and are on the same side as the regulating valve.

[0033] It is understandable that this arrangement allows the control module, flow sensor 5, regulating valve and other components on the mass flow controller to be more centralized, so as to facilitate installation and packaging.

[0034] In one embodiment, Figure 1-4 As shown, the mass flow controller includes a stainless steel housing 2 for encapsulating a control module, a flow sensor 5 and a regulating valve on a Y-shaped tube body 1; wherein the stainless steel housing 2 is screwed to the Y-shaped tube body 1.

[0035] It is understandable that the stainless steel housing 2 can centrally package the control module, the flow sensor 5 and the regulating valve on the Y-shaped tube body 1 to improve the explosion-proof performance of the mass flow controller and enable the mass flow controller to be used in explosion-proof places.

[0036] In one embodiment, Figure 2 and Figure 4 As shown, a display screen 18 is provided on the control module, and a tempered glass window 4 is provided on the stainless steel housing 2 , and the position of the tempered glass window 4 matches the position of the display screen 18 .

[0037] It can be understood that the relevant parameters of the mass flow controller can be displayed on the display screen 18, that is, the relevant parameters of the mass flow controller can be viewed through the tempered glass window 4, and the parameters can be conveniently set using an infrared hand operator; in addition, the tempered glass window 4 can be 10 mm to meet explosion-proof requirements.

[0038] It should be noted that a hole body for installing a tempered glass window 4 is partially provided on the stainless steel shell 2, and the tempered glass window 4 is pressed onto the stainless steel shell 2 by a first pressing plate 19, and the first pressing plate 19 is connected to the stainless steel shell 2 by screws; in addition, a sealing ring is installed between the tempered glass window 4 and the stainless steel shell 2 to seal the gap between the tempered glass window 4 and the stainless steel shell 2. In one embodiment, the flow sensor 5 is a thermal flow sensor, and specifically a thermal wind speed sensor with publication number CN217305211U.

[0039] It can be understood that thermal flow sensors such as thermal wind speed sensors are smaller in size, have a wider measurement range and higher measurement accuracy, which is convenient for mass flow controller integration and can collect data more accurately; specifically, the measurement range of this thermal flow sensor can reach 1:150, and the measurement accuracy is generally 0.5%~2%.

[0040] In one embodiment, the rotation driving mechanism 14 is a stepping motor.

[0041] It is understandable that the stepper motor can precisely control the rotation angle, so as to facilitate precise control of the opening of the flow channel through the valve core 7, thereby enabling the mass flow controller to perform more accurately.

[0042] It should be noted that in order to reduce the volume, traditional mass flow controllers on the market often use pilot valves as regulating valves, which control the switching time of the switch electromagnet in the pilot hole through PWM pulses to control the amount of gas flowing through the pilot valve. The gas flowing through the pilot valve pushes the piston of the main valve to control the opening of the piston. That is, this method has very high requirements on the pressure range of the pipeline. It cannot be opened at low pressure or zero pressure and cannot be applied to low-pressure places. The present invention adopts the principle of a direct-acting electric single-seat valve, which directly controls the opening by controlling the number of rotation steps of the stepper motor, and has no other auxiliary driving measures, and can be applied to pipeline flow control at low pressure or zero pressure. In one embodiment, Figure 4 As shown, the worm gear reducer includes a worm wheel 17 and a worm 16 meshing with each other. The worm 16 is coaxially fixedly connected to the output end of the rotation driving mechanism 14 , and the worm wheel 17 is coaxially fixedly connected to the push rod 11 .

[0043] It can be understood that the rotary drive mechanism 14 drives the worm 16 to rotate, so as to drive the worm wheel 17 meshing with the worm 16 to rotate, thereby driving the push rod 11 to rotate.

[0044] In one embodiment, Figure 4 As shown, the push rod 11 is rotatably connected to the valve cage cover 10 through a bearing 12 , and a bearing cover 13 for axially limiting the bearing 12 is fixedly connected to the valve cage cover 10 .

[0045] It can be understood that such a configuration enables the push rod 11 to rotate more smoothly on the valve cage cover 10 by utilizing the bearing 12 , and the bearing cover 13 can axially limit the bearing 12 on the valve cage cover 10 .

[0046] In one embodiment, Figure 4 As shown, the screw structure includes a screw nut 8 clamped in the valve core 7 and an external thread arranged at one end of the push rod 11, and the external thread matches the internal thread of the screw nut 8; a nut cover 9 for axially limiting the screw nut 8 is laser welded on the end of the valve core 7 close to the valve cage cover 10, and a polygonal column is arranged on the end of the nut cover 9 away from the valve core 7, and a polygonal hole slidably connected to the polygonal column is arranged on the end of the valve cage cover 10 close to the valve core 7.

[0047] It can be understood that one end of the push rod 11 with an external thread can be used as a lead screw, and since the lead screw nut 8 is clamped in the valve core 7, and the valve cage cover 10 can limit the rotation of the valve core 7 by limiting the rotation of the nut cover 9, when the push rod 11 rotates, the lead screw nut 8 can drive the valve core 7 to slide in the axial direction to adjust the flow channel opening.

[0048] It should be noted that a non-circular hole is provided at one end of the valve core 7 close to the nut cover 9, and the cross-sectional shape of the screw nut 8 matches the cross-sectional shape of the non-circular hole, that is, the screw nut 8 cannot rotate relative to the non-circular hole, and the depth of the non-circular hole is slightly larger than the thickness of the screw nut 8, so that the screw nut 8 can slide slightly in the non-circular hole, thereby preventing the valve core 7 from being affected by the jamming of the external thread on the push rod 11 and the internal thread of the screw nut 8.

[0049] It should also be noted that the polygonal hole may be a square hole, and accordingly, a quadrangular prism is provided at one end of the nut cover 9 away from the valve core 7 .

[0050] In one embodiment, Figure 4 As shown, a first seal 22 is provided between the flow sensor 5 and the second pipeline 102, a second seal 25 is provided between the valve cage 6 and the first pipeline 101, a third seal 24 is provided between the valve cage cover 10 and the valve cage 6, a fourth seal 26 is provided between the valve core 7 and the valve cage 6, and a fifth seal 23 is provided between the push rod 11 and the valve cage cover 10.

[0051] It can be understood that the first seal 22 can seal the gap between the flow sensor 5 and the second pipe 102 to prevent the fluid from leaking outward from the gap between the flow sensor 5 and the second pipe 102; the second seal 25 can seal the gap between the valve cage 6 and the first pipe 101 to prevent the fluid from leaking outward from the gap between the valve cage 6 and the first pipe 101; the third seal 24 can seal the gap between the valve cage cover 10 and the valve cage 6 to prevent the fluid from leaking outward through the gap between the valve core 7 and the valve cage 6 and the gap between the valve cage cover 10 and the valve cage 6. The fourth sealing member 26 can seal the gap between the valve core 7 and the valve cage 6 to prevent the fluid from flowing through the gap between the valve core 7 and the valve cage 6 to the gap between the valve cage cover 10 and the valve cage 6 or the gap between the push rod 11 and the valve cage cover 10; the fifth sealing member 23 can seal the gap between the push rod 11 and the valve cage cover 10 to prevent the fluid from leaking out through the gap between the push rod 11 and the valve cage cover 10; in addition, by adopting these sealing measures, the explosion-proof performance of the mass flow controller can be further improved on the basis of improving the mass flow controller.

[0052] It should be noted that the first sealing member 22 is a sealing ring sleeved on the flow sensor 5, and the sealing ring together with the flow sensor 5 is pressed on the second pipe 102 by the second pressure plate 21, and the second pressure plate 21 is screwed to the second pipe 102; the second sealing member 25 is two sealing rings sleeved on the valve cage 6 to improve the sealing performance here, and a mounting groove for mounting the second sealing member 25 is provided at a corresponding position on the outer side of the valve cage 6; the third sealing member 24 is a sealing ring, and a mounting groove for mounting the third sealing member 24 is provided on an end face of the valve cage cover 10 close to the valve cage 6 Groove; the fourth seal 26 is a sealing ring sleeved on the valve core 7, and a mounting groove for installing the fourth seal 26 is set at a corresponding position on the outer side of the valve core 7, and a retaining ring for axially limiting the fourth seal 26 and a retaining spring for axially limiting the retaining ring are also sleeved on the valve core 7; the fifth seal 23 is a sealing ring sleeved on the push rod 11 to play a secondary sealing role, and two retaining rings and a retaining spring are also sleeved on the push rod 11, wherein one retaining ring is located between the fifth seal 23 and the bearing 12, and the other retaining ring is located between the fifth seal 23 and the retaining spring.

[0053] In one embodiment, Figure 1-4As shown, the control module includes two printed circuit boards 20 fixedly connected in the stainless steel housing 2 and an electrical connector 3 arranged on the stainless steel housing 2. The two printed circuit boards 20 constitute a circuit board assembly, and the circuit board assembly is electrically connected to the lead end of the flow sensor 5, the electrical connector 3 and the display screen 18; the circuit board assembly collects the flow signal measured by the flow sensor 5 and converts it into a corresponding flow value to be displayed on the display screen 18, and controls the stepping motor to perform flow measurement and interlocking adjustment of the valve opening to achieve intelligent flow control.

[0054] Specifically, Figure 5 As shown, the circuit board assembly is provided with a power system circuit, an MCU control circuit, a regulating valve drive circuit, a sensor front end, a display and infrared receiving circuit, and a communication circuit; wherein, the mass flow controller is powered by a 24VDC input, and the power system circuit isolates and stabilizes the external input 24VDC voltage to the working voltage required by each unit circuit, specifically 12VDC, 8VDC, 5VDC and 3.3VDC; the MCU control circuit is the main control chip circuit of the mass flow controller, which interfaces with each unit circuit through the corresponding communication port to realize the functions of flow sensor 5 signal acquisition, regulating valve control signal output, external communication interface signal output, display screen 18 and infrared reception; the regulating valve drive circuit isolates the pulse signal output by the MCU control circuit and level conversion, and sends the converted drive signal to the stepper motor to realize the regulating valve opening control function; the sensor front end collects the flow signal input by the flow sensor 5 and performs front-end amplification processing, and then transmits it to the signal acquisition circuit of the MCU control circuit to realize the conversion and measurement of the flow signal; the display and infrared receiving circuit includes a display circuit and an infrared receiving circuit. The display circuit displays the display data sent by the MCU control circuit through a liquid crystal display screen 18, specifically displaying relevant parameters and menus. The infrared receiving circuit mainly realizes the signal reception of the infrared hand operator, and provides a human-computer exchange interface for parameter setting and viewing of the mass flow controller; the communication circuit receives external control instruction data and parameter setting data, and sends relevant flow parameters and control parameters of the MCU control circuit to external use.

[0055] The working steps of the present invention include: The mass flow controller is powered on and initialized; The flow sensor 5 is subjected to temperature collection, specifically, the temperature values ​​of two temperature sensors in the flow sensor 5 are collected; Determine whether the temperature difference between the two temperature sensors is a specified value; If the temperature difference between the two temperature sensors is not the specified value, the heating power supply of the temperature sensors is controlled, and the temperature values ​​of the two temperature sensors are collected again, and it is determined whether the temperature difference between the two temperature sensors is the specified value, until the temperature difference between the two temperature sensors is the specified value; If the temperature difference between the two temperature sensors is a specified value, the current mass flow rate of the fluid medium is calculated according to the control parameters of the flow sensor 5; Send the current mass flow rate of the fluid medium to the display screen 18 and read the mass flow rate value set by the infrared hand operator; The current mass flow rate of the fluid medium is compared with the set mass flow rate value; if the current mass flow rate of the fluid medium is different from the set mass flow rate value, the stepper motor control pulses of the corresponding number of pulses are calculated and output through the PID algorithm to achieve the purpose of controlling the regulating valve; if the current mass flow rate of the fluid medium is the same as the set mass flow rate value, the flow sensor 5 continues to collect temperature for circulation, so that the mass flow rate of the fluid medium flowing through the second pipeline 102 reaches the required set value.

[0056] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A mass flow controller, characterized in that: include: A Y-shaped tube body (1), the Y-shaped tube body (1) comprising a first pipe (101), a second pipe (102) for inputting fluid, and a third pipe (103) for outputting fluid; A flow sensor (5), wherein a detection end of the flow sensor (5) is located in the second pipe (102); A regulating valve, the regulating valve comprising a valve cage (6) fixedly connected in the first pipeline (101), a valve cage cover (10) covered on the valve cage (6), a valve core (7) slidably connected in the valve cage (6), a push rod (11) rotatably connected to the valve cage cover (10), and a rotation driving mechanism (14) fixedly connected to the valve cage cover (10), wherein the axis of the valve cage (6), the axis of the valve core (7) and the axis of the push rod (11) all coincide with the axis of the first pipeline (101). , the rotation centerline of the rotation drive mechanism (14) is perpendicular to the axis of the first pipeline (101), the rotation drive mechanism (14) is connected to the push rod (11) via a worm gear reducer, the push rod (11) is connected to the valve core (7) via a lead screw structure, and the end of the valve cage (6) is provided with a flow channel for connecting the second pipeline (102) and the third pipeline (103), wherein when the rotation drive mechanism (14) is in operation, the valve core (7) gradually adjusts the opening of the flow channel; A control module, the control module being electrically connected to the flow sensor (5) and the rotation drive mechanism (14).

2. A mass flow controller according to claim 1, characterized in that: The control module and the flow sensor (5) are both fixedly connected to the second pipeline (102) and on the same side as the regulating valve.

3. A mass flow controller according to claim 2, characterized in that: It comprises a stainless steel housing (2) for encapsulating the control module, the flow sensor (5) and the regulating valve on the Y-shaped tube body (1).

4. A mass flow controller according to claim 3, characterized in that: The control module is provided with a display screen (18), and the stainless steel housing (2) is provided with a tempered glass window (4), wherein the position of the tempered glass window (4) matches the position of the display screen (18).

5. A mass flow controller according to claim 1, characterized in that: The flow sensor (5) is a thermal flow sensor.

6. A mass flow controller according to claim 1, characterized in that: The rotation driving mechanism (14) is a stepping motor.

7. A mass flow controller according to claim 1, characterized in that: The worm gear reducer comprises a worm wheel (17) and a worm (16) which mesh with each other, the worm (16) being coaxially fixedly connected to the output end of the rotary drive mechanism (14), and the worm wheel (17) being coaxially fixedly connected to the push rod (11).

8. A mass flow controller according to claim 1, characterized in that: The push rod (11) is rotatably connected to the valve cage cover (10) via a bearing (12); a bearing cover (13) for axially limiting the bearing (12) is fixedly connected to the valve cage cover (10).

9. A mass flow controller according to claim 1, characterized in that: The lead screw structure comprises a lead screw nut (8) clamped in the valve core (7) and an external thread arranged at one end of the push rod (11), wherein the external thread matches the internal thread of the lead screw nut (8); a nut cover (9) for axially limiting the lead screw nut (8) is fixedly connected to one end of the valve core (7) close to the valve cage cover (10), and a polygonal column is arranged at one end of the nut cover (9) away from the valve core (7), and a polygonal hole slidably connected to the polygonal column is arranged at one end of the valve cage cover (10) close to the valve core (7).

10. A mass flow controller according to any one of claims 1 to 9, characterized in that: A first seal (22) is provided between the flow sensor (5) and the second pipe (102); and / or a second seal (25) is provided between the valve cage (6) and the first pipe (101); and / or a third seal (24) is provided between the valve cage cover (10) and the valve cage (6); and / or a fourth seal (26) is provided between the valve core (7) and the valve cage (6); and / or a fifth seal (23) is provided between the push rod (11) and the valve cage cover (10).

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