阅读说明：本技术 一种数字式空气流量开关及其测试方法 (Digital air flow switch and testing method thereof ) 是由 黄慈克 明雪桥 王久强 于 2020-08-17 设计创作，主要内容包括：本发明公开了一种数字式空气流量开关及其测试方法,包括流量开关壳体、入口气管接头、出口气管接头和数显控制模块,流量开关壳体前端连接入口气管接头并设有入口过滤组件,流量开关壳体后端连接出口气管接头并设有出口过滤部件,流量开关壳体连接壳体盖、数显控制模块,壳体盖的侧端设有连线接头,壳体盖内设有功能电路板,流量开关壳体与壳体盖之间位置设有传感器模块,传感器模块与功能电路板电性连接,功能电路板与数显控制模块电连接。本发明的有益效果是：数显控制模块与流量开关壳体旋转连接,便于操作人员使用；传感器模块设有基准热敏电阻和探测热敏电阻,通过电阻值的变化测量流速,其具有成本低、体积小、响应快的优点。(The invention discloses a digital air flow switch and a testing method thereof, and the digital air flow switch comprises a flow switch shell, an inlet air pipe joint, an outlet air pipe joint and a digital display control module, wherein the front end of the flow switch shell is connected with the inlet air pipe joint and is provided with an inlet filtering component, the rear end of the flow switch shell is connected with the outlet air pipe joint and is provided with an outlet filtering component, the flow switch shell is connected with a shell cover and the digital display control module, the side end of the shell cover is provided with a connecting wire joint, a functional circuit board is arranged in the shell cover, a sensor module is arranged between the flow switch shell and the shell cover and is electrically connected with the functional circuit board, and the functional circuit. The invention has the beneficial effects that: the digital display control module is rotationally connected with the flow switch shell, so that the use by an operator is facilitated; the sensor module is provided with a reference thermistor and a detection thermistor, and the flow rate is measured through the change of the resistance value, so that the sensor module has the advantages of low cost, small volume and quick response.)

1. A digital air flow switch, characterized by: comprises a flow switch shell and an inlet air pipe joint, outlet gas pipe joint and digital display control module, inlet gas pipe joint is connected to the front end of flow switch casing, outlet gas pipe joint is connected to the rear end of flow switch casing, be equipped with entry filter assembly between flow switch casing and the inlet gas pipe joint, be equipped with the export filter part between flow switch casing and the outlet gas pipe joint, the casing lid is installed to the upper end of flow switch casing, but the upper end swivelling joint digital display control module of casing lid, the side of casing lid is equipped with the line connection who is used for connecting power and signal transmission, be equipped with the function circuit board in the casing lid, the position is equipped with the sensor module between flow switch casing and the casing lid, the sensor module extends to inside the flow switch casing, sensor module and function circuit board electric connection, the function circuit board is connected with digital display control module electricity.

2. A digital air flow switch according to claim 1, wherein: the sensor module comprises a reference thermistor, a detection thermistor and a sensor support, the sensor support is installed in the flow switch shell in a limiting mode, the reference thermistor and the detection thermistor are installed on the sensor support and extend to the interior of the flow switch shell, the reference thermistor is located at one end close to the inlet air pipe joint, and the detection thermistor is located at one end close to the outlet air pipe joint.

3. A digital air flow switch according to claim 2, wherein: the function circuit board is provided with a constant temperature circuit module and a constant current source circuit module, the constant temperature circuit module is electrically connected with the reference thermistor, and the constant current source circuit module is electrically connected with the detection thermistor.

4. A digital air flow switch according to claim 3, wherein: the entry filter assembly includes 3 layers of filter screens, 2 filter screen retainer plates and 3 locating pins, is equipped with the constant head tank on the filter screen, is equipped with the locating hole on the filter screen retainer plate, and 3 layers of filter screens are stacked in turn with 2 filter screen retainer plates, and the locating pin corresponds spacing in constant head tank and locating hole.

5. A digital air flow switch according to claim 4, wherein: the outlet filter part is a single-layer filter screen.

6. A digital air flow switch according to claim 3, wherein: the upper end of the shell cover is provided with an annular interface, the digital display control module comprises a plurality of digital display shells, the bottom of each digital display shell is provided with an annular bulge corresponding to the annular interface, the annular interface is connected with the annular bulge, and the digital display control module can rotate around the annular interface.

7. A digital air flow switch according to claim 6, wherein: the digital display control module further comprises a key regulating and controlling board and an input and output panel, the key regulating and controlling board is installed inside the digital display shell, the input and output panel is installed on the upper end surface of the digital display shell, the input and output panel is provided with plastic keys and a liquid crystal screen, the plastic keys are physically connected with the key regulating and controlling board, the liquid crystal screen is electrically connected with the key regulating and controlling board, and the key regulating and controlling board is electrically connected with the functional circuit board.

8. A digital air flow switch according to claim 3, wherein: a joint rubber core is arranged in the connecting line joint, and an O-shaped sealing ring is arranged between the connecting line joint and the joint rubber core for sealing connection.

9. A digital air flow switch according to claim 3, wherein: and sealing parts are arranged at the connecting positions of the flow switch shell, the inlet air pipe connector, the outlet air pipe connector and the shell cover, and the connecting position of the shell cover and the digital display control module is also provided with the sealing parts.

10. An air flow testing method, which adopts the digital air flow switch of any one of claims 3-9 to test, and comprises the following steps:

(1) connecting fluid pipelines at the inlet air pipe joint and the outlet air pipe joint, confirming that the direction of the fluid is correct, connecting a connecting wire joint to a power supply and a signal wire, and starting to work;

(2) the constant current source circuit module on the functional circuit board performs constant current heating on the detection thermistor, and the reference thermistor does not perform heating; the fluid flows through the sensor module and deprives the heat of the detection thermistor and the reference thermistor, the resistance values of the detection thermistor and the reference thermistor are increased, the flow rate of the fluid is detected according to the increase rate of the resistance value of the detection thermistor relative to the resistance value of the reference thermistor, the constant temperature circuit module compensates the ambient temperature of the sensor module and the temperature of the fluid, and the measurement can be stably carried out within the using temperature range;

(3) and after the change of the resistance value and the fluid flow rate are detected, the detected value is output to an externally connected intelligent device through the connecting line joint, and the current fluid flow rate test is completed.

Technical Field

The invention relates to the technical field of air flow switches, in particular to a digital air flow switch.

Background

The air flow switch is mainly applied to industrial automation, air compression industry, refrigeration and air conditioning industry and used for measuring various gas flows.

The air flow switch comprises a vane type air valve flow switch, a hot film type flow switch, a karman vortex type flow switch and an ultrasonic flow switch. The commonly used air door blade type air flow switch mainly detects the flow according to the opening of a pushing valve during air intake, has simple structure and high reliability, but has large air intake resistance, slow response and large volume; the hot film type air flow switch mainly detects the flow of intake air according to the heat dissipation of air blown through a hot film, because the hot film type sensor does not use a platinum wire as a hot wire, but a thermistor, a compensation resistor, a bridge resistor and the like are manufactured by a thick film process, and a heating element does not directly bear the acting force generated by the air flow on the same ceramic substrate, thereby increasing the strength of the heating element, further improving the reliability, reducing the error, having better performance and high cost; the Karman vortex flow switch judges air inflow according to the disturbance air flow intensity when air enters, the ultrasonic flow switch detects air inlet flow according to the interference ultrasonic wave of air inlet size, and the type is non-contact, the sensor is isolated from fluid, the response speed is slow, the error is large, and the like.

In combination with the defects, the existing air flow switch has the outstanding problems of large movable part volume, slow non-contact response, high cost and the like.

Moreover, when the air flow switch is installed, the display orientation of the digital display component cannot be guaranteed to face the operator, and the inconvenience of using the air flow switch by the operator is caused.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a digital air flow switch, which is used for overcoming the defects of the prior art.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a digital air flow switch comprises a flow switch shell and an inlet air pipe joint, outlet gas pipe joint and digital display control module, inlet gas pipe joint is connected to the front end of flow switch casing, outlet gas pipe joint is connected to the rear end of flow switch casing, be equipped with entry filter assembly between flow switch casing and the inlet gas pipe joint, be equipped with the export filter part between flow switch casing and the outlet gas pipe joint, the casing lid is installed to the upper end of flow switch casing, but the upper end swivelling joint digital display control module of casing lid, the side of casing lid is equipped with the line connection who is used for connecting power and signal transmission, be equipped with the function circuit board in the casing lid, the position is equipped with the sensor module between flow switch casing and the casing lid, the sensor module extends to inside the flow switch casing, sensor module and function circuit board electric connection, the function circuit board is connected with digital display control module electricity.

Among the technical scheme, the sensor module includes benchmark thermistor, surveys thermistor and sensor holder, and the sensor holder is spacing to be installed in the flow switch casing, and inside benchmark thermistor and the detection thermistor installed on the sensor holder and extended to the flow switch casing, the benchmark thermistor is located to be close to and is located to be close to entry trachea joint one end, surveys thermistor and is located to be close to exit trachea joint one end.

In the technical scheme, the functional circuit board is provided with a constant temperature circuit module and a constant current source circuit module, the constant temperature circuit module is electrically connected with the reference thermistor, and the constant current source circuit module is electrically connected with the detection thermistor.

In the technical scheme, the inlet filtering component comprises 3 layers of filtering screens, 2 filtering screen fixing rings and 3 positioning pins, wherein the filtering screens are provided with positioning grooves, the filtering screen fixing rings are provided with positioning holes, the 3 layers of filtering screens and the 2 filtering screen fixing rings are alternately stacked, and the positioning pins are correspondingly limited in the positioning grooves and the positioning holes;

in the technical scheme, the outlet filter part is a single-layer filter screen.

In the technical scheme, the upper end of the shell cover is provided with an annular interface, the digital display control module comprises a digital display shell, the bottom of the digital display shell is provided with an annular bulge corresponding to the annular interface, the annular interface is connected with the annular bulge, and the digital display control module can rotate around the annular interface.

In the technical scheme, a wave washer, a circular washer and a clamp spring are arranged between the annular interface and the annular bulge to be tightly connected.

Among the technical scheme, digital display control module still includes button regulation and control board, input/output panel, and the button regulation and control board is installed inside the digital display casing, and input/output panel installs the upper end surface at the digital display shell, is equipped with plastic button and LCD screen on the input/output panel, and the plastic button is connected with button regulation and control board physics, LCD screen and button regulation and control board electric connection, button regulation and control board and functional circuit board electric connection.

In the technical scheme, a joint rubber core is arranged in the connecting line joint, and an O-shaped sealing ring is arranged between the connecting line joint and the joint rubber core for sealing connection.

In the technical scheme, the connecting positions of the flow switch shell, the inlet air pipe connector, the outlet air pipe connector and the shell cover are respectively provided with a sealing element, and the connecting positions of the shell cover and the digital display control module are also provided with the sealing elements.

An air flow test method adopts a digital air flow switch in the technical scheme to test, and the specific method is as follows:

(1) connecting fluid pipelines at the inlet air pipe joint and the outlet air pipe joint, confirming that the direction of the fluid is correct, connecting a connecting wire joint to a power supply and a signal wire, and starting to work;

(2) the constant current source circuit module on the functional circuit board performs constant current heating on the detection thermistor, and the reference thermistor does not perform heating; the fluid flows through the sensor module and deprives the heat of the detection thermistor and the reference thermistor, the resistance values of the detection thermistor and the reference thermistor are increased, the flow rate of the fluid is detected according to the increase rate of the resistance value of the detection thermistor relative to the resistance value of the reference thermistor, the constant temperature circuit module compensates the ambient temperature of the sensor module and the temperature of the fluid, and the measurement can be stably carried out within the using temperature range;

(3) and after the change of the resistance value and the fluid flow rate are detected, the detected value is output to an externally connected intelligent device through the connecting line joint, and the current fluid flow rate test is completed.

The invention has the beneficial effects that: the digital display control module is rotationally connected with the flow switch shell, so that the use by an operator is facilitated; the sensor module is provided with a reference thermistor and a detection thermistor, and the flow rate is measured through the change of the resistance value, so that the sensor module has the advantages of low cost, small volume and quick response.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a schematic view of the overall exploded structure of the present invention.

Fig. 3 is a schematic view of the construction of the flow switch housing of the present invention.

Fig. 4 is a schematic view of the structure of the sensor module of the present invention.

Fig. 5 is an exploded view of the housing cover and the digital display bottom cover according to the present invention.

Fig. 6 is an exploded view of the inlet filter assembly of the present invention.

Fig. 7 is a schematic circuit diagram of a functional circuit board in the present invention.

Reference numerals

1. A flow switch housing; 11. an air inlet; 12. an air outlet; 13. a housing cover; 131. a functional circuit board; 132. a ring interface; 14. connecting a wire joint; 141. an interface rubber core; 15. a groove structure; 151. a slot; 16. a flow direction indicator; 2. an inlet air pipe joint; 3. an outlet gas pipe joint; 4. a digital display control module; 41. a digital display bottom shell; 411. an annular projection; 42. a digital display shell; 43. a key control board; 44. an input-output panel; 441. plastic keys; 442. a liquid crystal screen; 443. a light guide disc; 444. a light guide strip; 445. a filter sticker; 5. a sensor module; 51. a reference thermistor; 511. a first sensor; 512. a first electrode copper needle; 513. a second electrode copper needle; 52. detecting a thermistor; 521. a second sensor; 522. a third electrode copper needle; 523. a fourth electrode copper needle; 53. a sensor holder; 61. a filter screen; 611. positioning a groove; 62. a filter screen fixing ring; 621. positioning holes; 63. positioning pins; 71. a first seal member; 72. a second seal member; 73. a third seal member; 74. a wave washer; 75. a circular washer; 76. a clamp spring; 77. and an O-shaped sealing ring.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1-3, a digital air flow switch comprises a flow switch shell 1, an inlet air pipe joint 2, an outlet air pipe joint 3 and a digital display control module 4; flow switch casing 1 has air inlet 11 and air outlet 12, air inlet 11 and air outlet 12 locate flow switch casing 1's front and back both ends, inlet air pipe connector 2 is connected to flow switch casing 1's air inlet 11, outlet air pipe connector 3 is connected to flow switch casing 1's air outlet 12, casing lid 13 is installed to flow switch casing 1's upper end, but casing lid 13's upper end swivelling joint digital display control module 4, but digital display control module 4 carries out arbitrary angle rotation on casing lid 13, a side end of casing lid 13 is equipped with line connector 14.

The upper end of the flow switch shell 1 is provided with a groove structure 15, the shell cover 13 is installed at the position of the groove structure 15 in a limiting mode, the flow switch shell 1 and the shell cover 13 are connected in a sealing mode through a first sealing element 71, and the flow switch shell 1 and the shell cover 13 are fastened through screws. The sensor module 5 is arranged between the flow switch shell 1 and the shell cover 13, a slotted hole 151 for installing the sensor module 5 is further arranged in the groove structure 15, the size structure of the slotted hole 151 is matched with the sensor module 5, and the sensor module 5 is installed in the slotted hole 151 in a limiting mode. As shown in fig. 4, the sensor module 5 includes a reference thermistor 51, a detection thermistor 52, and a sensor holder 53, the sensor holder 53 is mounted in the slot 151 of the flow switch case 1, the sensor holder 53 is hermetically connected to the flow switch case 1 by a second sealing member 72, the reference thermistor 51 is not heated as a reference member, the detection thermistor 52 is heated as a detection member, the reference thermistor 51 and the detection thermistor 52 are mounted on the sensor holder 53 and protrude toward the inside of the flow switch case 1, the reference thermistor 51 is located near the inlet air pipe joint 2, and the detection thermistor 52 is located near the outlet air pipe joint 3. Air enters the flow switch shell 1 from the inlet air pipe joint 2 and passes through the reference thermistor 51 and the detection thermistor 52 in sequence, heat on the detection thermistor 52 is taken away by the air, the resistance value changes, and the difference value of the two resistances is used as the basis for judging the flow rate. Specifically, the reference thermistor 51 includes a first sensor 511, a first electrode copper needle 512, and a second electrode copper needle 513, the first sensor 511 connects the first electrode copper needle 512 and the second electrode copper needle 513 to read temperature data, the detection thermistor 52 includes a second sensor 521, a third electrode copper needle 522, and a fourth electrode copper needle 523, and the second sensor 521 connects the third electrode copper needle 522 and the fourth electrode copper needle 523 to read temperature data.

Wherein, a flow direction indicating mark 16 is further provided at the upper end of the flow switch housing 1 for distinguishing the air inlet 11 and the air outlet 12 of the flow switch housing 1.

A functional circuit board 131 for monitoring the sensor module 5 is provided in the housing cover 13, and the functional circuit board 131 is electrically connected to the sensor module 5. Specifically, the functional circuit board 131 is provided with a constant temperature circuit module and a constant current source circuit module, the constant temperature circuit module is electrically connected to the first sensor 511, the first electrode copper needle 512 and the second electrode copper needle 513 of the reference thermistor 51, and the constant current source circuit module is electrically connected to the second sensor 521, the third electrode copper needle 522 and the fourth electrode copper needle 523 of the detection thermistor 52.

The constant temperature circuit module comprises SENSOR IN, R211, R21, R20, R19, R22, R23 and U1-C, forms a constant temperature circuit network as shown IN FIG. 7, and is used for controlling the reference temperature of the reference thermistor 51 to be constant and enabling stable measurement within the use temperature range. The constant current source circuit modules comprise a SENSOR OUT, U1-A, TR1, R1, R2, R3, R4, R5, R6, R7 and R33, the constant current source circuit modules form a constant current source circuit network as shown in FIG. 7, the constant current source circuit modules are used for controlling the constant heat obtained by power supply and heating of the detection thermistor 52, the constant current source circuit modules supply power to the detection thermistor 52 for constant current and heating through the SENSOR OUT, once fluid flows through the constant current source circuit modules, the heat on the detection thermistor 52 is deprived, the resistance value of the detection thermistor 52 rises when the heat is deprived, the rising rate of the resistance value is related to the flow rate of the fluid, and the flow rate can be detected by measuring the resistance value.

As shown in fig. 2 and fig. 5, an annular interface 132 is provided at the upper end of the housing cover 13, and the annular interface 132 is used for rotatably connecting with the digital display control module 4. The digital display control module 4 comprises a digital display shell, a key control board 43 and an input/output panel 44, the digital display shell comprises a digital display bottom shell 41 and a digital display shell 42, and the digital display bottom shell 41 and the digital display shell 42 are hermetically connected by a third sealing element 73 and are fastened by screws; the lower end surface of the digital display bottom shell 41 is provided with an annular protrusion 411 matched with the annular interface 132, the annular interface 132 and the annular protrusion 411 are tightly connected through a wave gasket 74, a circular gasket 75 and a snap spring 76, and the connection sealing performance is ensured through an O-shaped sealing ring 77. Annular protrusion 411 can rotate for annular interface 132, adjusts digital display control module 4's angular position, makes things convenient for operating personnel to operate the use to the air flow switch of different installation directions.

The key control board 43 is installed inside the digital display shell, the input/output panel 44 is installed on the upper end surface of the digital display shell 42, the input/output panel 44 is provided with a plastic key 441 and a liquid crystal screen 442, the plastic key 441 is physically connected with the key control board 43, the key control board 43 is controlled by pressing the corresponding plastic key 441, the liquid crystal screen 442 displays data on the input/output panel 44 through a light guide disk 443, a light guide strip 444 and a light filter sticker 445, the liquid crystal screen 442 is electrically connected with the key control board 43, and the key control board 43 is electrically connected with the functional circuit board 131 to read and control data of the sensor module 5.

A connecting line joint 14 is arranged at one side end of the shell cover 13, the connecting line joint 14 is used for connecting the input and the output of a power supply and signals, an interface rubber core 141 is arranged in the connecting line joint 14, and an O-shaped sealing ring 77 is arranged between the connecting line joint 14 and the interface rubber core 141 to ensure the connection sealing performance.

Fig. 2 is combined with fig. 6 to show, an inlet filter assembly is arranged between the air inlet 11 of the flow switch housing 1 and the inlet air pipe joint 2, the inlet filter assembly includes 3 layers of filter screens 61, 2 filter screen fixing rings 62 and 3 positioning pins 63, each filter screen 61 is provided with a positioning groove 611, each filter screen fixing ring 62 is provided with a positioning hole 621, the 3 layers of filter screens 61 and the 2 filter screen fixing rings 62 are alternately stacked, and the positioning pins 63 are correspondingly limited on the positioning grooves 611 of the filter screens 61 and the positioning holes 621 of the filter screen fixing rings 62. The inlet air pipe joint 2 is hermetically connected with the inlet filtering component by an O-shaped sealing ring 77.

An outlet filter component is arranged between the air outlet 12 of the flow switch shell 1 and the outlet air pipe joint 3, the outlet filter component is a 1-layer filter screen 61, and the outlet filter component is hermetically connected with the outlet air pipe joint 3 through an O-shaped sealing ring 77.

The testing method of the digital air flow switch comprises the following steps:

(1) connecting fluid pipelines at the inlet gas pipe joint 2 and the outlet gas pipe joint 3, confirming that the direction of the fluid is correct, and connecting a connecting joint 14 to a power supply and a signal line to start working;

(2) the constant current source circuit module on the functional circuit board 131 performs constant current heating on the detection thermistor 52, and the reference thermistor 51 does not perform heating; the fluid flows through the sensor module 5 and deprives the heat of the detection thermistor 52 and the reference thermistor 51, the resistance value of the detection thermistor 52 and the reference thermistor 51 rises, the flow rate of the fluid is detected according to the rising rate of the resistance value of the detection thermistor 52 relative to the resistance value of the reference thermistor 51, the constant temperature circuit module compensates the ambient temperature of the sensor module 5 and the temperature of the fluid, and the measurement can be stably carried out in the use temperature range;

(3) when the change of the resistance value and the fluid flow rate are detected, the detected value is output to an intelligent device connected externally through the connecting joint 14, and the current fluid flow rate test is completed.

The above examples are intended to illustrate rather than to limit the invention, and all equivalent changes and modifications made by the methods described in the claims of the present invention are intended to be included within the scope of the present invention.