Built-in motor valve for negative-pressure-resistant helium detection

Abstract

The built-in motor valve comprises a valve body, a valve seat, a valve cover, a motor, a speed reducing mechanism, a screw rod, a nut, a sealing cover and a sealing bag, the valve seat is fixedly connected with the valve body, the valve cover is arranged between the valve seat and the valve body, the speed reducing mechanism is arranged in the valve seat, the motor is arranged beside the speed reducing mechanism, the screw rod, the nut, the sealing cover and the sealing bag are arranged in the valve body, the motor, the speed reducing mechanism and the screw rod sequentially form transmission connection, and the nut is in threaded fit with the screw rod. The sealing cover is arranged on the nut and matched with a valve port of the valve body in a sealing mode, the first end of the sealing bag is connected to the valve body and / or the valve cover in a sealing mode, the inner periphery of the second end of the sealing bag is provided with a lip edge arranged outside the nut in a sleeving mode, and the outer wall of the nut is provided with a blind hole matched with the lip edge. The built-in motor valve resistant to negative pressure helium detection is simple and reasonable in structure and capable of effectively bearing negative pressure helium detection of an intelligent gas meter.

Description

Technical Field

[0001] The utility model relates to the technical field of motor valves, in particular to a built-in motor valve capable of resisting negative pressure helium detection. Background Art

[0002] After assembly, smart gas meters are typically tested with negative pressure helium to verify their tightness. During this test, the meter must be evacuated.

[0003] The built-in motor valve is a major component of smart gas meters, primarily used to control the opening and closing of gas meters. The structure of a built-in motor valve typically includes a valve body, valve seat, valve cover, motor, and reduction gear set. The valve seat is fixedly connected to the valve body via the valve cover. The motor and reduction gear set are cooperatively arranged within the valve seat. The valve body is respectively provided with a screw, nut, and sealing cover. The motor, reduction gear set, and screw form a transmission connection in sequence. The nut is threadedly engaged with the screw, and the sealing cover is arranged on the nut and seals with the valve port of the valve body. During operation, the motor drives the screw to rotate through the reduction gear set. As the screw rotates, the sealing cover is driven by the nut to move along the axial direction of the screw, thereby achieving the purpose of controlling the opening and closing of the valve port.

[0004] To isolate natural gas, a rubber sealing bladder is typically installed within the valve body. One end of the bladder is sealingly connected to the valve body and / or bonnet, while the other end of the bladder is provided with a lip on its inner periphery that fits over the exterior of the nut. The lip allows the bladder to slide in a sealing manner against the exterior of the nut.

[0005] While the sealing bladder can effectively seal and isolate natural gas, it creates a cavity between the inner wall of the bladder and the outer wall of the nut. During the negative pressure helium inspection of a smart gas meter, when the meter is evacuated, the air in the cavity between the bladder and the nut is extracted, leaving the cavity in a vacuum state. Due to the pressure differential between the inside and outside of the bladder and its own elastic force, the lip of the bladder tightly adheres to the outer wall of the nut, causing the nut to be tightly gripped by the bladder, resulting in a "stuck neck" phenomenon. This prevents the nut from moving normally, easily causing the motor to stall, and in turn, causing the motor valve to malfunction.

[0006] To address these issues, some useful attempts have been made in the prior art. For example, a Chinese invention patent (publication number CN117028641A) discloses a built-in motor valve for a smart gas meter with a pressure-balancing function. This valve uses a one-way valve on the gearbox to balance the pressure difference between the inside and outside of the sealing capsule, thereby preventing the nut from seizing. However, the need for a one-way valve complicates the structure, increasing manufacturing costs and assembly difficulty.

[0007] Therefore, it is necessary to further improve the existing technology. Utility Model Content

[0008] The purpose of the utility model is to provide a built-in motor valve resistant to negative pressure helium detection in response to the defects and shortcomings of the existing technology. The valve has a simple and reasonable structure and can effectively withstand the negative pressure helium detection test of the intelligent gas meter.

[0009] In order to achieve the above-mentioned purpose, the present utility model adopts the following technical solutions.

[0010] A built-in motor valve resistant to negative pressure helium inspection, comprising a valve body, a valve seat, a valve cover, a motor, a speed reduction mechanism, a screw, a nut, a sealing cover and a sealing capsule;

[0011] The valve seat is fixedly connected to the valve body, a valve cover is provided between the valve seat and the valve body, the speed reduction mechanism is provided in the valve seat, the motor is provided beside the speed reduction mechanism, the screw, the nut, the sealing cover and the sealing capsule are all provided in the valve body, the motor, the speed reduction mechanism and the screw sequentially constitute a transmission connection, the nut is threadedly engaged with the screw, the sealing cover is provided on the nut and sealingly engaged with the valve port of the valve body, a first end of the sealing capsule is sealingly connected to the valve body and / or the valve cover, an inner periphery of the second end of the sealing capsule is provided with a lip sleeved on the outside of the nut, and the sealing capsule is sealingly slidably engaged with the outer wall of the nut through the lip;

[0012] The outer wall of the nut is provided with a blind hole that cooperates with the lip. The blind hole is located on the motion trajectory of the relative sliding of the nut and the lip. The opening width of the blind hole along the axial direction of the nut is adapted to the thickness of the lip.

[0013] Furthermore, the blind hole is located in the middle of the outer wall of the nut.

[0014] Furthermore, the inner wall of the lip is provided with an annular groove extending along the circumference of the lip.

[0015] Furthermore, the outer periphery of the first end of the sealing bag is tightly pressed between the valve body and the valve cover in a sealing manner.

[0016] Furthermore, the upper end of the screw extends into the valve seat, the upper end of the screw is provided with a linkage lug, and the output end of the speed reduction mechanism is provided with a transmission protrusion that cooperates with the linkage lug.

[0017] Furthermore, a gear cavity is formed in the valve seat, and the speed reduction mechanism is arranged in the gear cavity.

[0018] Furthermore, a cover plate is provided at the upper end of the valve seat, a motor cavity is formed between the cover plate and the valve seat, the motor is provided in the motor cavity, the output end of the motor extends into the gear cavity, and the output end of the motor is transmission-connected to the input end of the reduction mechanism.

[0019] Furthermore, the cover plate is provided with a through hole, a plug is provided in the through hole, and the plug is provided with a wire hole for leading out the power line of the motor.

[0020] Furthermore, the speed reduction mechanism is a reduction gear or a reduction gear set.

[0021] The beneficial effects of the present invention are as follows: after the built-in motor valve provided by the present invention is assembled to the intelligent gas meter, the motor valve is first adjusted to the open valve state before the gas meter is subjected to negative pressure helium inspection. During the negative pressure helium inspection of the gas meter, although the air in the cavity formed between the sealing capsule and the nut will be extracted during the vacuum treatment, there is also the phenomenon that the sealing capsule holds the nut tightly under the action of the internal and external pressure difference and its own elastic force. However, since the outer wall of the nut is provided with a blind hole that cooperates with the lip of the sealing capsule, after the negative pressure helium inspection is completed, when the gas meter is removed from the detection instrument, the external air will be quickly replenished into the valve body. At this time, the motor is started to control the motor valve to close the valve, and the motor drives the nut along the axis through the reduction mechanism and the screw. The nut moves in the opposite direction, thereby driving the sealing cover to move synchronously. In the initial stage of the nut movement, the sealing bag holds the nut tightly, the nut moves slowly, and the working current of the motor is large. As the nut continues to move, when the blind hole on the outer wall of the nut moves to the lip position of the sealing bag, at this time, since the inside of the sealing bag is in a vacuum state, and the lip is affected by the atmospheric pressure outside the sealing bag, under the action of the internal and external pressure difference, the lip of the sealing bag will be deformed relative to the blind hole, and air enters the cavity formed by the sealing bag and the nut through the gap between the lip and the blind hole, thereby balancing the internal and external pressure difference of the sealing bag, so that the lip of the sealing bag no longer holds the nut tightly, the sealing bag returns to normal state, the working current of the motor decreases accordingly, and the motor valve resumes normal operation.

[0022] In summary, the built-in motor valve resistant to negative pressure helium detection provided by the present invention has a simple and reasonable structure and can effectively withstand the negative pressure helium detection test of the intelligent gas meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the utility model.

[0024] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the utility model.

[0025] Figure 3 yes Figure 2 Enlarged structural diagram at point A in the middle.

[0026] Figure 1-Figure 3 middle:

[0027] 1. Valve body; 11. Valve port; 2. Valve seat; 21. Cover plate; 22. Through hole; 23. Plug; 24. Wire hole; 3. Valve cover; 4. Motor; 5. Speed ​​reduction mechanism; 51. Transmission bump; 6. Screw; 61. Linkage lug; 7. Nut; 71. Blind hole; 8. Sealing cover; 9. Sealing capsule; 91. Lip; 92. Ring groove; S. Cavity. DETAILED DESCRIPTION

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

[0029] like Figures 1 to 3 The shown embodiment shows a built-in motor valve resistant to negative pressure helium inspection, whose main components include a valve body 1, a valve seat 2, a valve cover 3, a motor 4, a reduction mechanism 5, a screw 6, a nut 7, a sealing cover 8 and a sealing bag 9.

[0030] The valve seat 2 is fixedly connected to the valve body 1, and a valve cover 3 is provided between the valve seat 2 and the valve body 1. The valve cover 3 isolates the internal space of the valve body 1 from the internal space of the valve seat 2. The reduction mechanism 5 is provided in the valve seat 2, and the motor 4 is provided beside the reduction mechanism 5. In this embodiment, in order to optimize the layout and make the structure of the motor valve more compact, a gear cavity is formed in the valve seat 2, and the reduction mechanism 5 is provided in the gear cavity. A cover plate 21 is provided at the upper end of the valve seat 2, and a motor cavity is formed between the cover plate 21 and the valve seat 2. The motor 4 is provided in the motor cavity. The output end of the motor 4 extends into the gear cavity, and the output end of the motor 4 is transmission-connected to the input end of the reduction mechanism 5.

[0031] Furthermore, in order to achieve a better deceleration effect and a more stable and reliable transmission, in this embodiment, the deceleration mechanism 5 is configured as a reduction gear. Of course, in other embodiments, the deceleration mechanism 5 can also be configured as a reduction gear set as needed, and a multi-stage deceleration can be formed by the reduction gear set. A through hole 22 is provided on the cover plate 21, and a plug 23 is provided in the through hole 22. The plug 23 is provided with a wire hole 24 for leading out the power cord of the power supply machine 4. By providing the plug 23 and the wire hole 24, the power cord is led out and the need for leading out the power cord is met. At the same time, it is also beneficial to improve the sealing effect of the motor cavity.

[0032] The screw 6, nut 7, sealing cap 8, and sealing capsule 9 are all disposed within the valve body 1. The motor 4, reduction mechanism 5, and screw 6 sequentially form a transmission connection. In this embodiment, the upper end of the screw 6 extends into the valve seat 2. A linkage lug 61 is provided on the upper end of the screw 6. The output end of the reduction mechanism 5 is provided with a transmission protrusion 51 that engages with the linkage lug 61. When the motor 4 drives the reduction mechanism 5 to operate, the reduction mechanism 5 engages with the linkage lug 61 through the transmission protrusion 51, driving the screw 6 to rotate.

[0033] Nut 7 is sleeved onto the exterior of screw 6, threadedly engaging with the latter. Sealing cap 8 is mounted on nut 7 and seals against valve port 11 of valve body 1. When motor 4 drives screw 6 to rotate via reduction mechanism 5, the threaded engagement causes nut 7 to drive sealing cap 8 to move axially relative to screw 6, thereby controlling the opening and closing of valve port 11 and thereby controlling the opening and closing of the motor-operated valve.

[0034] The first end of the sealing capsule 9 is sealingly connected to the valve body 1 and / or the valve cover 3. The inner periphery of the second end of the sealing capsule 9 is provided with a lip 91 that is sleeved onto the outside of the nut 7. The sealing capsule 9 slides sealingly with the outer wall of the nut 7 via the lip 91. In this embodiment, to enhance the sealing effect of the sealing capsule 9 and ensure a more secure installation of the sealing capsule 9, the outer periphery of the first end of the sealing capsule 9 is sealingly pressed between the valve body 1 and the valve cover 3.

[0035] See also Figure 2 and Figure 3 The outer wall of the nut 7 is provided with a blind hole 71 that mates with the lip 91. The blind hole 71 is located on the relative sliding trajectory of the nut 7 and the lip 91. The opening width of the blind hole 71 along the axial direction of the nut 7 is adapted to the thickness of the lip 91. Specifically, in this embodiment, the opening width of the blind hole 71 along the axial direction of the nut 7 is slightly smaller than the thickness of the lip 91. For example, in this embodiment, the thickness L1 of the lip 91 of the sealing capsule 9 is approximately 1.2 mm, the depth L2 of the blind hole 71 is approximately 20 mm, and the diameter D of the blind hole 71 (i.e., the opening width) is approximately 1 mm. Of course, in other embodiments, the size of the blind hole 71 may vary depending on the thickness of the lip 91.

[0036] Preferably, the blind hole 71 and the lip 91 are completely offset when the motor valve is in the closed and open states. In this embodiment, the blind hole 71 is located in the middle of the outer wall of the nut 7. After the negative pressure helium test is completed and the motor 4 is started, the blind hole 71 is located in the middle of the outer wall of the nut 7, which shortens the time required for the blind hole 71 to move to the position corresponding to the lip 91 of the sealing capsule 9. This allows the pressure difference between the inside and outside of the sealing capsule 9 to be restored to equilibrium more quickly, which helps shorten the time the motor valve operates abnormally after the negative pressure helium test.

[0037] In this embodiment, the inner wall of the lip 91 is provided with an annular groove 92 extending along the circumference of the lip 91. By providing the annular groove 92, the lip 91 is more flexible and the sealing performance of the nut 7 is better. At the same time, after the negative pressure helium test, when the blind hole 71 moves to the corresponding position of the lip 91, it is more conducive to the deformation of the lip 91 under the action of the internal and external pressure difference, which is conducive to restoring the balance of the internal and external pressure difference of the sealing bag 9.

[0038] The working principle of the built-in motor valve resistant to negative pressure helium detection provided by the present invention is the same as that in the prior art, so it will not be described in detail here.

[0039] The built-in motor valve provided by the present invention is assembled to an intelligent gas meter. Before the gas meter is subjected to negative pressure helium testing, the motor valve is first adjusted to an open state, that is, the sealing cover 8 is controlled to be away from the valve port 11, so that the valve port 11 is open. During the negative pressure helium testing of the gas meter, although the air in the cavity S formed between the sealing capsule 9 and the nut 7 will be extracted during the vacuum treatment, there is also the phenomenon that the sealing capsule 9 holds the nut 7 tightly due to the internal and external pressure difference and its own elastic force. However, since the outer wall of the nut 7 is provided with a blind hole 71 that cooperates with the lip 91 of the sealing capsule 9, after the negative pressure helium testing is completed, when the gas meter is removed from the testing instrument, the external air will be quickly replenished into the valve body 1. At this time, the motor 4 is started to control the motor valve to close the valve. The motor 4 drives the nut 7 to move axially through the reduction mechanism 5 and the screw 6, thereby driving the sealing cover 8 to move synchronously. During the initial stages of nut 7's movement, the sealing capsule 9 grips the nut 7, causing it to move slowly and resulting in a high operating current for the motor 4. As the nut 7 continues to move, the blind hole 71 in the outer wall of the nut 7 moves to the lip 91 of the sealing capsule 9. Due to the internal and external pressure differential, the sealing capsule 9 is in a vacuum state, while the lip 91 is subjected to the atmospheric pressure outside the sealing capsule 9. Air enters the cavity S formed by the sealing capsule 9 and the nut 7 through the gap between the lip 91 and the blind hole 71 (since the nut 7 is still moving slowly at this point, air can fully enter this cavity). This balances the internal and external pressure differentials between the sealing capsule 9, causing the lip 91 of the sealing capsule 9 to no longer grip the nut 7, returning the sealing capsule 9 to its normal state. The operating current of the motor 4 decreases, allowing the motor valve to resume normal operation. After the internal and external pressure differentials between the sealing capsule 9 and the nut 7 are balanced, the sealing capsule 9 no longer grips the nut 7, eliminating the need for further vacuuming, regardless of the forward or reverse rotation of the motor 4.

[0040] As mentioned above, since air has been added to the cavity formed between the sealing capsule 9 and the nut 7 during the first valve closing operation after the negative pressure helium test, when natural gas is introduced into the gas meter (that is, the gas meter has passed the test and is put into use), the pressure of the natural gas entering the motor valve is relatively small, generally only 2KPa-5KPa, which is a low-pressure fluid medium. Therefore, when the motor valve is opened and closed, although the blind hole 71 will move to the position corresponding to the lip 91, this low-pressure natural gas cannot overcome the air pressure inside the sealing capsule 9 and the self-elasticity of the sealing capsule 9 to cause the lip 91 to deform, so that the natural gas will not enter the interior of the sealing capsule 9 through the gap between the lip 91 and the blind hole 71, thereby ensuring that the natural gas will not enter the valve seat 2. Moreover, after the pressure difference between the inside and outside of the sealing bag 9 is balanced, its lip 91 will not hold the nut 7 tightly. Therefore, when the motor valve is opened and closed, the movement speed of the nut 7 is also relatively fast, so that when the blind hole 71 passes through the lip 91, the contact time between the two will be short (that is, the blind hole 71 quickly passes through the lip 91 along with the nut 7), making it difficult for natural gas to penetrate from the gap between the lip 91 and the blind hole 71.

[0041] The above description is only a preferred embodiment of the present invention. Therefore, any equivalent changes or modifications made according to the structure, features and principles described in the scope of the present invention patent application are included in the scope of the present invention patent application.

Claims

1. A built-in motor valve resistant to negative pressure helium inspection, comprising a valve body, a valve seat, a valve cover, a motor, a speed reduction mechanism, a screw, a nut, a sealing cover and a sealing capsule; The valve seat is fixedly connected to the valve body, a valve cover is provided between the valve seat and the valve body, the speed reduction mechanism is provided in the valve seat, the motor is provided beside the speed reduction mechanism, the screw, the nut, the sealing cover and the sealing capsule are all provided in the valve body, the motor, the speed reduction mechanism and the screw sequentially constitute a transmission connection, the nut is threadedly engaged with the screw, the sealing cover is provided on the nut and sealingly engaged with the valve port of the valve body, a first end of the sealing capsule is sealingly connected to the valve body and / or the valve cover, an inner periphery of the second end of the sealing capsule is provided with a lip sleeved on the outside of the nut, and the sealing capsule is sealingly slidably engaged with the outer wall of the nut through the lip; Its characteristics are: The outer wall of the nut is provided with a blind hole that cooperates with the lip. The blind hole is located on the motion trajectory of the relative sliding of the nut and the lip. The opening width of the blind hole along the axial direction of the nut is adapted to the thickness of the lip.

2. The negative pressure helium detection resistant built-in motor valve according to claim 1, characterized in that: The blind hole is located in the middle of the outer wall of the nut.

3. The negative pressure helium detection resistant built-in motor valve according to claim 1, characterized in that: The inner wall of the lip is provided with an annular groove extending along the circumference of the lip.

4. The internal motor valve capable of resisting negative pressure helium detection according to claim 1, characterized in that: The outer periphery of the first end of the sealing bag is tightly pressed between the valve body and the valve cover.

5. The internal motor valve capable of resisting negative pressure helium detection according to claim 1, characterized in that: The upper end of the screw rod extends into the valve seat, the upper end of the screw rod is provided with a linkage lug, and the output end of the speed reduction mechanism is provided with a transmission cam that cooperates with the linkage lug.

6. The internal motor valve capable of resisting negative pressure helium detection according to claim 1, characterized in that: A gear cavity is formed in the valve seat, and the speed reduction mechanism is arranged in the gear cavity.

7. The internal motor valve capable of resisting negative pressure helium detection according to claim 6, characterized in that: A cover plate is provided at the upper end of the valve seat, and a motor cavity is formed between the cover plate and the valve seat. The motor is provided in the motor cavity, and the output end of the motor extends into the gear cavity. The output end of the motor is transmission-connected to the input end of the reduction mechanism.

8. The negative pressure helium detection resistant built-in motor valve according to claim 7, characterized in that: The cover plate is provided with a through hole, a plug is provided in the through hole, and the plug is provided with a wire hole for leading out the power line of the motor.

9. The internal motor valve capable of resisting negative pressure helium detection according to claim 1, characterized in that: The speed reduction mechanism is a speed reduction gear or a speed reduction gear set.

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