An explosion-proof card membrane type gas meter

Abstract

The present invention relates to the technical field of diaphragm gas meters, and provides an explosion-proof card diaphragm gas meter to ensure that the gas meter is always in a safe gas pressure state, seal the suddenly appearing abnormal high pressure in front of the gas meter, and prevent the gas meter from bursting. The gas meter comprises a meter case consisting of an upper shell, a lower shell and a locking step, a counter box is installed through the front wall of the meter case, a counter, a power module and a wireless radio frequency transmitter I are built in the counter box, a gas inlet and a gas outlet are arranged at the upper end of the meter case, an explosion-proof device is installed on the gas inlet, a card display meter is arranged at the upper end of the explosion-proof device, two meter boxes are arranged at the lower part of the inner cavity of the meter case, and a membrane is arranged vertically in the inner cavity of the meter box; the present invention is particularly suitable for the safe explosion-proof of IC card diaphragm gas meters, and has a high commercial prospect.

Description

Technical Field

[0001] The invention relates to the technical field of diaphragm gas meters, and in particular to an explosion-proof card diaphragm gas meter. Background Art

[0002] The fuel people use for cooking has changed from conventional energy sources such as firewood and coal, which waste resources and cause serious pollution, to clean energy such as natural gas and coal gas, and even electricity. Here, the gas meter will play its role. Its automatic accumulation function allows those who use natural gas or pipeline gas to easily know how much gas they have used, so that they can pay according to the cubic meters of gas consumed each month.

[0003] The diaphragm gas meter is a type of gas meter, which refers to a volumetric mechanical instrument with a metering system composed of two containers (metering boxes). Each container is separated in the middle by a concave diaphragm, which divides each container into two metering chambers of complementary shapes. The driving force of the diaphragm movement depends on the gas pressure difference at the inlet and outlet of the gas meter. Under the action of the pressure difference, the diaphragm produces continuous alternating movement, pushing the two sets of slide valves to continuously separate the gas filled in the metering chamber into a single metering volume (circulation volume) and discharge it to the outlet, and then connected to the counter through a mechanical transmission mechanism to count the single metering volume, thereby measuring the total amount of gas flowing through the pipeline. At present, the card diaphragm gas meters on the market are all mechatronic intelligent prepaid gas metering instruments. That is, pay first and then use. A card display meter is installed on the diaphragm gas meter for swiping the card to measure the use of gas.

[0004] The gas meter is the weakest link in the gas pipeline network in terms of pressure. It can only withstand limited gas pressure. Once the gas pressure exceeds the designed limit pressure of the gas meter, the gas meter will deform and crack, causing gas leakage, combustion or even explosion when encountering open flames. At the same time, the gas meter has built-in circuits. When there is a problem with the circuit, high temperature and sparks will be generated, resulting in combustion or even explosion. Most of the existing gas meters can only be used to record usage data, with a single function and cannot effectively respond to the above usage situations. Therefore, how to ensure that the gas meter is always in a safe state and resolve sudden abnormal situations before the gas meter, this is the key to preventing the gas meter from bursting.

[0005] For this purpose, we propose an explosion-proof card membrane type gas meter. Summary of the invention

[0006] (1) Technical issues to be solved

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art, meet the actual needs, and provide an explosion-proof diaphragm gas meter to ensure that the gas meter is always in a safe gas pressure state, seal the sudden abnormal high pressure in front of the gas meter, and prevent the gas meter from bursting.

[0008] (2) Technical solution

[0009] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is:

[0010] An explosion-proof card membrane type gas meter, comprising a meter case consisting of an upper shell, a lower shell and a clamping step, a counter box is installed through the front wall of the meter case, the counter box has a counter, a power module and a wireless radio frequency transmitter I built in, a gas inlet and a gas outlet are arranged at the upper end of the meter case, an explosion-proof device is installed on the gas inlet, a card display meter is arranged at the upper end of the explosion-proof device, two metering boxes are arranged at the lower part of the inner cavity of the meter case, and a membrane is vertically arranged in the inner cavity of the metering box, a left slide valve and a right slide valve are respectively installed at the upper ends of the two metering boxes, the left slide valve and the right slide valve are connected to the input end of the counter through a crank connecting rod, and the output ends of the two metering boxes are connected to the gas outlet;

[0011] The explosion-proof device comprises a valve body, a gas inlet pipe installed on the side wall of the valve body, an upper threaded tube and a fastener respectively installed at the upper and lower ends of the valve body, the card display meter is threadedly installed on the upper end of the upper threaded tube, the lower part of the fastener extends the inner cavity of the first sleeve, and the first sleeve is fixedly inserted on the gas inlet, the lower end of the side wall of the first sleeve is penetrated and installed with a connecting shell, and the inner cavity of the connecting shell is provided with a pressure change valve assembly, the other end of the connecting shell is penetrated and installed with the lower part of the side wall of the second sleeve, the upper end of the second sleeve reaches the outer cavity of the meter case and is sleeved with an upper tube cover;

[0012] The valve body comprises a valve body shell and a sealing valve plug slidably mounted in the inner cavity of the valve body shell, the upper end of the sealing valve plug is mounted with the output end of a small cylinder, and the small cylinder is fixedly mounted on the inner top wall of the valve body shell.

[0013] Preferably, the fastener includes an internal insert tube installed through the lower end of the valve body shell, the lower end of the internal insert tube reaches the inner cavity of the first sleeve and is installed with a table-shaped nozzle, the upper part of the side wall of the internal insert tube is sequentially sleeved with a limit sleeve and a hexagonal internal thread sleeve from top to bottom, and the hexagonal internal thread sleeve is threadedly installed on the upper part of the first sleeve.

[0014] Preferably, the pressure valve changing assembly comprises an upper valve changing component and a lower valve changing component which match each other, the upper valve changing component comprises an air intake slide pipe which is inserted through the table-shaped nozzle, and an electromagnetic ring is installed at the lower end of the air intake slide pipe, a telescopic spring is sleeved on the air intake slide pipe, and the two ends of the telescopic spring are respectively connected to the lower end of the table-shaped nozzle and the upper end of the electromagnetic ring;

[0015] The lower valve-changing component includes a driven gear rotatably mounted on the inner bottom wall of the connecting shell, and a plurality of valve core tubes matching the air intake slide pipe are mounted on the upper end edge of the driven gear, a rubber air sealing ring is sleeved on the annular outer wall of the valve core tube, a permanent magnet ring is sleeved on the valve core tube, and the permanent magnet ring is fixedly mounted on the upper end of the driven gear, and prefabricated air ports of different calibers that pass through the driven gear are opened in the middle of the plurality of valve core tubes, the driven gear is meshed with a driving gear, and the driving gear is mounted on the output end of the motor, and the motor is fixedly mounted on the inner wall of the second sleeve.

[0016] Preferably, an explosion-proof control component is provided at the upper end of the motor, and the explosion-proof control component includes an explosion-proof circuit board arranged at the upper end of the motor, and four explosion-proof TVS diodes are distributed in a matrix at the upper end of the explosion-proof circuit board, and the four explosion-proof TVS diodes are connected in series with each other, two positive and negative terminals are installed on both sides of the upper end of the explosion-proof circuit board, and a wireless radio frequency transmitter II is also provided at the upper end of the explosion-proof circuit board.

[0017] Preferably, the plurality of prefabricated gas ports are distributed in a ring array, and the inner diameters of the plurality of prefabricated gas ports are arranged in order from large to small.

[0018] Preferably, a lower annular sleeve is provided at the lower end of the driving gear, and the lower annular sleeve is fixedly mounted on the inner wall of the first sleeve, and the middle air hole of the lower annular sleeve matches the inner diameter of the prefabricated air port.

[0019] Preferably, the card display meter includes a display meter shell, a display screen and a magnetic card sensing area arranged at the front end of the display meter shell, the magnetic card sensing area is located below the display screen, the magnetic card sensing area has a built-in capacitive sensing circuit, and the display meter shell has a built-in wireless radio frequency receiver and a PLC controller.

[0020] Preferably, a first pressure sensor and a second pressure sensor are installed on the gas inlet pipe and the gas outlet, respectively, and the first pressure sensor and the second pressure sensor are both electrically connected to the PLC controller.

[0021] Preferably, the upper shell, the lower shell and the engaging step are all made of explosion-proof material components.

[0022] Preferably, an inner fixing plate is fixedly sleeved on the upper part of the annular side wall of the first sleeve and the second sleeve, and the inner fixing plate is fixedly mounted on the inner top wall of the upper shell by screws.

[0023] (3) Beneficial effects:

[0024] 1. This gas meter monitors the gas pressure on both sides of the gas inlet and gas outlet through a pressure sensor. The monitoring data is compared with the PLC controller in the database to determine the pressure of the gas inlet and outlet, thereby effectively adjusting the gas intake volume to ensure that the pressure is within the tolerable range of the gas meter and effectively prevent explosion.

[0025] 2. This diaphragm gas meter, through the setting of explosion-proof device, when the pipeline pressure is within the adjustable range, changes different prefabricated gas ports to adjust the pressure of the incoming gas; when the pipe pressure is too large and exceeds the adjustable range, the control valve body is closed to protect the diaphragm gas meter.

[0026] 3. This card membrane gas meter can effectively receive the gas usage value of the counter transmitted from the wireless radio frequency transmitter I through the setting of the card display meter, and automatically close the wall valve body when the gas volume is insufficient by combining the recharge value sensed by the capacitive sensing circuit; at the same time, it can effectively receive the circuit status transmitted from the wireless radio frequency transmitter II, and judge the safety of the circuit by combining with the PLC controller.

[0027] 4. This explosion-proof card membrane type gas meter uses the combined structure of the pressure valve component and the explosion-proof control component to start from the two aspects of intake pressure and circuit control, so that the pressure in the gas meter is under the set pressure and the circuit is safe, thereby protecting the gas meter from being damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the appearance of the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the body of the present invention;

[0030] Figure 3 This is a schematic diagram of the appearance of the explosion-proof device of the present invention;

[0031] Figure 4 It is a schematic diagram of the explosion-proof device structure in the present invention;

[0032] Figure 5 It is a top view of the lower valve changing component structure in the present invention;

[0033] Figure 6 This is a schematic diagram of the explosion-proof control component structure of the present invention;

[0034] Figure 7 for Figure 4 Top view of the structure.

[0035] In the figure: upper shell 1, lower shell 2, engaging step 3, counter box 4, gas outlet 5, explosion-proof device 6, valve body 61, valve body shell 611, small cylinder 612, sealing valve plug 613, gas inlet pipe 62, upper threaded pipe 63, buckle 64, internal plug-in pipe 641, hexagonal internal thread sleeve 642, limit sleeve 643, table nozzle 644, first sleeve 65, connecting shell 66, pressure change valve assembly 67, intake slide pipe 671, telescopic spring 672, electromagnetic ring 673, permanent magnet ring 674, valve core pipe 675, driven gear 676, pre- Gas control port 677, driving gear 678, motor 679, rubber sealing ring 670, second sleeve 68, explosion-proof control component 69, explosion-proof circuit board 691, explosion-proof TVS diode 692, positive and negative electrode connectors 693, wireless radio frequency transmitter II 694, upper tube cover 610, first pressure sensor 7, second pressure sensor 8, card display meter 9, display meter housing 91, display screen 92, magnetic card sensing area 93, membrane 10, left slide valve 11, right slide valve 12, crank connecting rod 13, metering box 14, inner fixing plate 15, lower annular sleeve 16. DETAILED DESCRIPTION

[0036] The following is combined with Figure 1-7 The present invention is further described with examples:

[0037] An explosion-proof card membrane type gas meter, including a meter case consisting of an upper shell 1, a lower shell 2 and a locking step 3, a counter box 4 is installed through the front wall of the meter case, and the counter box 4 has a counter, a power module and a wireless radio frequency transmitter I built in, a gas inlet and a gas outlet 5 are provided at the upper end of the meter case, an explosion-proof device 6 is installed on the gas inlet, and a card display meter 9 is provided at the upper end of the explosion-proof device 6, two metering boxes 14 are provided at the lower part of the inner cavity of the meter case, and a membrane 10 is vertically provided in the inner cavity of the metering box 14, and a left slide valve 11 and a right slide valve 12 are respectively installed at the upper ends of the two metering boxes 14, and the left slide valve 11 and the right slide valve 12 are connected to the input end of the counter through a crank connecting rod 13, and the output ends of the two metering boxes 14 are connected to the gas outlet 5 through.

[0038] In this example, if Figure 2As shown, the gas entering the meter case enters the air chamber in the inner cavity of the meter box 14 through the gas distribution valve on the meter box 14. The gas filled into the air chamber pushes the membrane 10 to move, and the connecting plate fixed on the surface of the membrane 10 drives the vertical shaft to produce a reciprocating rotation. The vertical shaft drives the crank connecting rod 13 to move, thereby driving the left slide valve 11 and the right slide valve 12 on the two meter boxes 14 to switch the inlet and outlet gas distribution of each air chamber. When the air chamber on one side of the membrane 10 in the meter box 14 is inflated, the gas Vi in the air chamber on the other side of the membrane 10 is discharged, and the membrane 10 reciprocates to discharge 2Vi gas. When the two meter boxes 1 When the air chambers on both sides of the membrane 10 of 4 complete one reciprocating motion, the gas discharged is 2×2Vi, which is called a rotation volume Vc. One reciprocating cycle discharges the volume of gas of two metering boxes 14. At the same time, the crank connecting rod 13 swings once, driving the output end of the counter to rotate. The reading of the counter is the volume of the discharged gas. Combined with the built-in counter, power module and wireless radio frequency transmitter I of the counter box 4, the digital changes of the counter can be effectively transmitted to the card display meter 9 through the wireless radio frequency transmitter I, so as to control the opening and closing of the valve body 61 and ensure the use of the gas after recharging.

[0039] In this embodiment, Figure 3 , 4 As shown in Figure 6, the explosion-proof device 6 includes a valve body 61, a gas inlet pipe 62 installed on the side wall of the valve body 61, an upper threaded pipe 63 and a fastener 64 installed at the upper and lower ends of the valve body 61, respectively. The card display meter 9 is threadedly installed on the upper end of the upper threaded pipe 63, and the lower part of the fastener 64 extends the inner cavity of the first sleeve 65, and the first sleeve 65 is fixedly inserted on the gas inlet. The lower end of the side wall of the first sleeve 65 is penetrated and installed with a connecting shell 66, and the inner cavity of the connecting shell 66 is provided with a pressure change valve assembly 67, and the other end of the connecting shell 66 is penetrated A second sleeve 68 is installed on the lower part of the side wall, and the upper end of the second sleeve 68 reaches the outer cavity of the meter case and is sleeved with an upper tube cover 610. The upper tube cover 610 can be effectively disassembled, and the parts can be taken out for maintenance without opening the meter case. The valve body 61 can effectively cut off the gas from entering the meter case. Combined with the fastener 64 that fixes the first sleeve 65, it effectively ensures that the gas enters the meter case in a sealed manner. At the same time, the setting of the pressure change valve assembly 67 can effectively control the change of the inlet diameter according to the pressure of the gas, thereby effectively controlling the gas pressure inside the meter case.

[0040] In this embodiment, Figure 4As shown, the valve body 61 includes a valve body shell 611 and a sealing valve plug 613 slidably installed in the inner cavity of the valve body shell 611, the upper end of the sealing valve plug 613 is installed with the output end of a small cylinder 612, and the small cylinder 612 is fixedly installed on the inner top wall of the valve body shell 611. When the small cylinder 612 is started, it pushes the sealing valve plug 613 to slide downward, blocking the input end of the gas inlet pipe 62, thereby cutting off the entry of gas.

[0041] In this embodiment, Figure 4 As shown, the fastener 64 includes an internal plug-in tube 641 installed through the lower end of the valve body shell 611, the lower end of the internal plug-in tube 641 reaches the inner cavity of the first sleeve 65 and is installed with a table-shaped nozzle 644, the upper part of the side wall of the internal plug-in tube 641 is sequentially sleeved with a limit sleeve 643 and a hexagonal internal thread sleeve 642 from top to bottom, and the hexagonal internal thread sleeve 642 is threadedly installed on the upper part of the first sleeve 65. Through the threaded installation of the hexagonal internal thread sleeve 642, the sealing connection between the valve body 61 and the first sleeve 65 is effectively guaranteed to prevent gas leakage, and it is easy to disassemble and maintain.

[0042] In this embodiment, Figure 4 and 5As shown, the pressure change valve assembly 67 includes an upper change valve component and a lower change valve component that match each other, which effectively controls the change of the inlet diameter according to the pressure of the gas, thereby effectively controlling the gas pressure inside the meter case. The upper change valve component includes an intake slide pipe 671 inserted through the table-shaped nozzle 644, and an electromagnetic ring 673 is installed at the lower end of the intake slide pipe 671. A telescopic spring 672 is sleeved on the intake slide pipe 671, and the two ends of the telescopic spring 672 are respectively connected to the lower end of the table-shaped nozzle 644 and the electromagnetic ring 673. 3 is connected to the upper end of the housing 66; the lower valve member includes a driven gear 676 rotatably mounted on the inner bottom wall of the connecting housing 66, and the upper edge of the driven gear 676 is equipped with a plurality of valve core tubes 675 matching the intake slide pipe 671, the annular outer wall of the valve core tube 675 is sleeved with a rubber sealing ring 670, the valve core tube 675 is sleeved with a permanent magnet ring 674, and the permanent magnet ring 674 is fixedly mounted on the upper end of the driven gear 676, and the middle part of the plurality of valve core tubes 675 is provided with different calibers that penetrate the driven gear 676 The prefabricated gas port 677, the driven gear 676 is meshed with the driving gear 678, and the driving gear 678 is installed on the output end of the motor 679, and the motor 679 is fixedly installed on the inner wall of the second sleeve 68. The electromagnetic ring 673 is energized to generate magnetism, attracting the permanent magnet ring 674 located below the electromagnetic ring 673, driving the air intake slide 671 to move downward and sleeve on the valve core tube 675. The rubber sealing ring 670 plays an effective sealing role. The gas passes through the prefabricated gas port opened in the middle of the valve core tube 675 and penetrates the driven gear 676. 677, enters the metering box 14 in the inner cavity of the meter case; when the intake pressure of the gas inlet pipe 62 increases or decreases, the valve body 61 is locked first, the electromagnetic ring 673 disconnects the power supply, and the intake slide pipe 671 moves upward under the rebound force of the telescopic spring 672, and then the motor 679 drives the active gear 678 to rotate, and the rotation cooperates with the prefabricated gas ports 677 of different calibers. Subsequently, the intake slide pipe 671 descends, the valve body 61 opens, and the gas enters after pressure adjustment through the prefabricated gas ports 677 of different calibers, effectively stabilizing the gas pressure in the meter case.

[0043] In this embodiment, Figure 4 and 6As shown, an explosion-proof control component 69 is provided at the upper end of the motor 679, and the explosion-proof control component 69 includes an explosion-proof circuit board 691 arranged at the upper end of the motor 679, and four explosion-proof TVS diodes 692 are distributed in a matrix at the upper end of the explosion-proof circuit board 691, and the four explosion-proof TVS diodes 692 are connected in series with each other, and two positive and negative connectors 693 are installed on both sides of the upper end of the explosion-proof circuit board 691. A wireless radio frequency transmitter II 694 is also provided at the upper end of the explosion-proof circuit board 691, and the two positive and negative connectors 693 are used to connect the welding feet of the motor 679. The welding feet of the motor 679 are inserted into the positive and negative connectors 693 of the explosion-proof circuit board 691, so that the explosion-proof circuit board 691, the motor 9, and the explosion-proof TVS diode 692 are connected together, which increases the safety and reliability of the circuit in the shell, and the wireless radio frequency transmitter II 694 can effectively transmit the circuit conditions in the explosion-proof circuit board 691 to the wireless radio frequency receiver to ensure the safety of the circuit.

[0044] In this embodiment, Figure 5 As shown, the plurality of prefabricated gas ports 677 are distributed in a circular array, and the inner diameters of the plurality of prefabricated gas ports 677 are arranged in sequence from large to small. The regularly arranged prefabricated gas ports 677 can effectively ensure that the rotation of the pressure changing valve assembly 67 matches the regulation of the gas pressure.

[0045] In this embodiment, Figure 4 As shown, a lower annular sleeve 16 is provided at the lower end of the driving gear 678, and the lower annular sleeve 16 is fixedly mounted on the inner wall of the first sleeve 65, and the middle air hole of the lower annular sleeve 16 matches the inner diameter of the prefabricated gas port 677, sealing the upper part of the driven gear 676 to prevent gas leakage, and combined with the matching prefabricated gas port 677, controlling the amount of gas entering, thereby adjusting the pressure of the inner cavity of the case.

[0046] In this embodiment, Figure 1 As shown, the card display meter 9 includes a display metering housing 91, a display screen 92 and a magnetic card sensing area 93 arranged at the front end of the display metering housing 91. The display screen 92 is used to display the user's remaining gas volume and the total gas usage. The magnetic card sensing area 93 is located below the display screen 92. The magnetic card sensing area 93 is built with a capacitive sensing circuit. The capacitive sensing circuit of the magnetic card sensing area 93 is used for the user to swipe the gas volume in the recharge card. The display metering housing 91 is built with a wireless radio frequency receiver and a PLC controller. In this embodiment, the model of the PLC controller is Siemens S7-200. The wireless radio frequency receiver can effectively receive the gas usage value of the counter transmitted by the wireless radio frequency transmitter I, combined with the recharge value sensed by the capacitive sensing circuit, when the gas volume is insufficient, the wall valve body 61 is automatically closed; the wireless radio frequency receiver can effectively receive the circuit clearing condition transmitted by the wireless radio frequency transmitter II 694, and judge the safety of the circuit in combination with the PLC controller.

[0047] In this embodiment, Figure 2 and 3 As shown, the first pressure sensor 7 and the second pressure sensor 8 are respectively installed on the gas inlet pipe 62 and the gas outlet 5, and the first pressure sensor 7 and the second pressure sensor 8 are both electrically connected to the PLC controller. The first pressure sensor 7 and the second pressure sensor 8 respectively sense the pressure of the gas in the gas inlet pipe 62 and the gas outlet 5. Combined with the PLC controller, when the pipeline pressure is within the adjustable range, different prefabricated gas ports 677 are changed to adjust the pressure of the incoming gas; when the pipeline pressure is too large and exceeds the adjustable range, the control valve body 61 is closed to protect the diaphragm gas meter.

[0048] In this embodiment, the upper shell 1, the lower shell 2 and the engaging step 3 are all made of explosion-proof material components, which effectively enhances the pressure-bearing capacity of the gas meter from the outside.

[0049] In this embodiment, Figure 3 and 4 As shown, the upper parts of the annular side walls of the first sleeve 65 and the second sleeve 68 are fixedly sleeved with an inner fixing plate 15, and the inner fixing plate 15 is fixedly mounted on the inner top wall of the upper shell 1 by screws, which effectively fixes the installation of the explosion-proof device 6 and seals the watch case for easy installation.

[0050] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. An explosion-proof card membrane type gas meter, comprising a meter case consisting of an upper shell, a lower shell and a card step, characterized in that: A counter box is installed through the front wall of the case, and the counter box has a counter, a power module and a wireless radio frequency transmitter I built in. A gas inlet and a gas outlet are provided at the upper end of the case, and an explosion-proof device is installed on the gas inlet. A card display meter is provided at the upper end of the explosion-proof device. Two metering boxes are provided at the lower part of the inner cavity of the case, and a membrane is vertically provided in the inner cavity of the metering box. A left slide valve and a right slide valve are respectively installed at the upper ends of the two metering boxes. The left slide valve and the right slide valve are connected to the input end of the counter through a crank connecting rod, and the output ends of the two metering boxes are connected to the gas outlet; The explosion-proof device comprises a valve body, a gas inlet pipe installed on the side wall of the valve body, an upper threaded tube and a fastener respectively installed at the upper and lower ends of the valve body, the card display meter is threadedly installed on the upper end of the upper threaded tube, the lower part of the fastener extends the inner cavity of the first sleeve, and the first sleeve is fixedly inserted on the gas inlet, the lower end of the side wall of the first sleeve is penetrated and installed with a connecting shell, and the inner cavity of the connecting shell is provided with a pressure change valve assembly, the other end of the connecting shell is penetrated and installed with the lower part of the side wall of the second sleeve, the upper end of the second sleeve reaches the outer cavity of the meter case and is sleeved with an upper tube cover; The valve body comprises a valve body shell and a sealing valve plug slidably mounted in the inner cavity of the valve body shell, the upper end of the sealing valve plug is mounted with the output end of a small cylinder, and the small cylinder is fixedly mounted on the inner top wall of the valve body shell; The fastener comprises an inner plug-in tube which is installed through the lower end of the valve body shell, the lower end of the inner plug-in tube reaches the inner cavity of the first sleeve and is installed with a table-shaped nozzle, the upper part of the side wall of the inner plug-in tube is sequentially sleeved with a limit sleeve and a hexagonal internal thread sleeve from top to bottom, and the hexagonal internal thread sleeve is threadedly installed on the upper part of the first sleeve; The pressure valve changing assembly comprises an upper valve changing component and a lower valve changing component which match each other, the upper valve changing component comprises an air intake slide pipe which is inserted through the table-shaped nozzle, and an electromagnetic ring is installed at the lower end of the air intake slide pipe, and a telescopic spring is sleeved on the air intake slide pipe, and the two ends of the telescopic spring are respectively connected to the lower end of the table-shaped nozzle and the upper end of the electromagnetic ring; The lower valve-changing component includes a driven gear rotatably mounted on the inner bottom wall of the connecting shell, and a plurality of valve core tubes matching the air intake slide pipe are mounted on the upper end edge of the driven gear, a rubber air sealing ring is sleeved on the annular outer wall of the valve core tube, a permanent magnet ring is sleeved on the valve core tube, and the permanent magnet ring is fixedly mounted on the upper end of the driven gear, and prefabricated air ports of different calibers that pass through the driven gear are opened in the middle of the plurality of valve core tubes, the driven gear is meshed with a driving gear, and the driving gear is mounted on the output end of the motor, and the motor is fixedly mounted on the inner wall of the second sleeve.

2. An explosion-proof card membrane type gas meter as claimed in claim 1, characterized in that: An explosion-proof control component is provided at the upper end of the motor, and the explosion-proof control component includes an explosion-proof circuit board arranged at the upper end of the motor, and four explosion-proof TVS diodes are distributed in a matrix at the upper end of the explosion-proof circuit board, and the four explosion-proof TVS diodes are connected in series with each other, two positive and negative terminals are installed on both sides of the upper end of the explosion-proof circuit board, and a wireless radio frequency transmitter II is also provided at the upper end of the explosion-proof circuit board.

3. An explosion-proof card membrane type gas meter as claimed in claim 1, characterized in that: The plurality of prefabricated gas ports are distributed in a ring array, and the inner diameters of the plurality of prefabricated gas ports are arranged in sequence from large to small.

4. The explosion-proof diaphragm gas meter according to claim 1, characterized in that: A lower annular sleeve is provided at the lower end of the driving gear, and the lower annular sleeve is fixedly mounted on the inner wall of the first sleeve, and the middle air hole of the lower annular sleeve matches the inner diameter of the prefabricated air port.

5. The explosion-proof diaphragm gas meter according to claim 1, characterized in that: The card display meter includes a display meter housing, a display screen and a magnetic card sensing area arranged at the front end of the display meter housing. The magnetic card sensing area is located below the display screen. A capacitive sensing circuit is built into the magnetic card sensing area. A wireless radio frequency receiver and a PLC controller are built into the display meter housing.

6. An explosion-proof diaphragm gas meter as claimed in claim 5, characterized in that: The gas inlet and the gas outlet are respectively installed with a first pressure sensor and a second pressure sensor, and the first pressure sensor and the second pressure sensor are both electrically connected to the PLC controller.

7. An explosion-proof diaphragm gas meter according to claim 1, characterized in that: The upper shell, the lower shell and the engaging step are all made of explosion-proof material components.

8. The explosion-proof card membrane type gas meter according to claim 1, characterized in that: An inner fixing plate is fixedly sleeved on the upper part of the annular side wall of the first sleeve and the second sleeve, and the inner fixing plate is fixedly mounted on the inner top wall of the upper shell body by screws.

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