High-vacuum push-pull valve

Abstract

The utility model belongs to the field of vacuum devices, and particularly relates to a high-vacuum push-pull valve. The high-vacuum push-pull valve comprises a valve body and a vacuum bottle plug movably assembled in the valve body through a valve rod, a vacuum pumping opening used for being connected with a vacuumizing device is formed in the valve body, internal threads are arranged at the bottom of the valve body and used for being in threaded fit with a connecting pipe for machining external threads, the vacuum bottle plug is in an inverted circular truncated cone shape, and the diameter of the vacuum bottle plug is gradually reduced from top to bottom. A conical surface matched with the peripheral surface of the vacuum bottle plug is arranged on the inner wall of a pipe opening of the connecting pipe; sealing rings are arranged between the inner wall of the valve body and the outer side wall of the connecting pipe and between the outer side wall of the vacuum bottle plug and the inner side wall of the connecting pipe. When the high-vacuum push-pull valve is actually applied, the operation steps are few, the sealing performance is high, and leakage is not prone to occurring.

Description

Technical Field

[0001] This utility model belongs to the field of vacuum devices, and specifically relates to a high vacuum push-pull valve. Background Technology

[0002] In the production of cryogenic Dewar flasks (such as LNG cylinders), dozens of cylinders need to be connected in parallel to create a vacuum between the outer shell and the inner liner to achieve thermal insulation. During vacuuming, a push-pull valve is used to change the flow or isolation between the vacuum unit and the evacuated liner. The vacuum push-pull valve plays a crucial role in the Dewar flask manufacturing process; air leakage is strictly prohibited during its pushing and pulling. Otherwise, no matter how high the vacuum level is achieved, air leakage during the final sealing of the vacuum stopper will render all previous work useless. A lack of vacuum in the cryogenic flask's liner is a direct cause of increased evaporation of liquid gas inside the flask. Achieving a superior vacuum level is a common concern for all cryogenic flask manufacturers and users.

[0003] Existing vacuum push-pull valves, such as the bellows-sealed vacuum push-pull valve disclosed in Chinese patent document CN203202255U, include a push-pull handle, a valve stem, and a valve body. The lower outer part of the valve body has threads that are threaded to a locking nut. A sealing washer is installed between the bottom of the valve body and the locking nut. A side opening is provided on the side of the valve body. The lower part of the valve stem has threads that connect to a vacuum bottle stopper. A bellows is installed on the outside of the valve stem. The lower part of the bellows is welded to the valve stem. A clamp plug is installed on the upper part of the valve body. The clamp plug and the valve body are fastened by clamps. A sealing gasket is installed between the clamp plug and the valve body. The upper end of the bellows is welded to the sealing gasket as a whole. Before vacuuming, first insert the gas outlet of the interlayer into the valve body from the bottom, connecting the lower port of the valve body to the gas outlet of the cryogenic bottle interlayer. Then tighten the lock nut and seal it with an O-ring. At this time, the side port of the valve body and the gas outlet of the interlayer are connected. Then connect the side port of the valve body to the vacuum unit, turn on the vacuum unit to start evacuating the gas in the interlayer. After reaching the required vacuum level, press the push-pull handle, insert the vacuum bottle plug into the gas outlet of the interlayer through the valve rod, and seal the interlayer with multiple O-rings. Then remove the clamp, loosen the lock nut at the bottom of the valve body, unscrew the valve rod from the vacuum bottle plug, and remove the valve body to start the next batch of Dewar flasks for interlayer vacuuming.

[0004] In existing vacuum push-pull valves, when a locking nut is used at the valve body and the interlayer (also called the pipe), the nut needs to be fixed and removed, which involves many steps in actual operation. In addition, the vacuum bottle stopper is made of a cylindrical grooved shape, which may cause vacuum leakage under high vacuum conditions. Utility Model Content

[0005] The purpose of this invention is to provide a high-vacuum push-pull gate to solve the technical problems of existing vacuum push-pull valves.

[0006] To solve the above problems, the present invention provides a high-vacuum push-pull valve with the following technical solution:

[0007] A high-vacuum push-pull valve includes a valve body and a vacuum stopper movably mounted in the valve body via a valve stem. The valve body has a vacuum port for connecting to a vacuum pumping device. The valve body is characterized by an internal thread at its bottom for engaging with a threaded connecting pipe with external threads. The vacuum stopper is frustum-shaped, with its diameter gradually decreasing from top to bottom. The inner wall of the connecting pipe has a tapered surface adapted to the outer circumferential surface of the vacuum stopper. Sealing rings are provided between the inner wall of the valve body and the outer wall of the connecting pipe, and between the outer wall of the vacuum stopper and the inner wall of the connecting pipe.

[0008] Furthermore, the outer wall of the vacuum stopper is provided with a plurality of sealing grooves arranged at intervals from top to bottom, and each sealing groove is equipped with a sealing ring.

[0009] Furthermore, the spacing between any two adjacent sealing grooves is equal.

[0010] Furthermore, the sealing groove is provided in three parts.

[0011] Furthermore, the connector includes an integrally formed sealing pipe section and a connecting pipe section. The external thread is provided on the connecting pipe section, and the sealing pipe section has a tapered hole. The wall surface of the tapered hole forms the tapered surface, and the minimum diameter of the tapered hole is larger than the diameter of the inner hole of the connecting pipe section.

[0012] Furthermore, the depth of the conical hole is greater than the height of the vacuum stopper.

[0013] Furthermore, the valve body is also provided with a bellows, which is sleeved on the valve stem and the lower end of the bellows is connected to the valve stem. The upper end of the bellows is connected to a plug for sealing the valve body. The valve stem and the plug are slidably assembled in the vertical direction. A clamp is provided on the outside of the plug for tightening the plug and the valve body. A sealing ring is also provided between the plug and the valve body.

[0014] Furthermore, the valve stem is coaxial with the vacuum stopper, and the bottom of the valve stem is threadedly connected to the vacuum stopper.

[0015] Furthermore, the end of the valve stem furthest from the vacuum stopper is provided with a handle rod perpendicular to the valve stem.

[0016] The beneficial effects of this utility model are as follows: The valve body of the high vacuum push-pull valve of this utility model is directly connected to the connecting pipe through a threaded connection. Compared with the existing vacuum push-pull valves that use a locking nut for connection, the operation steps of installing and removing the locking nut are eliminated during the vacuuming process, making operation more convenient. In addition, after using the inverted frustum-shaped vacuum bottle stopper, when the vacuum bottle stopper is inserted downward into the connecting pipe with a conical surface by pulling the rod, the vacuum bottle stopper will be subjected to uniform pressure from all directions of the interface due to the characteristics of the conical shape. This uniform pressure distribution makes the contact between the vacuum bottle stopper and the connecting pipe tighter, and the contact area between the two gradually increases, so that they can fit tightly from the edge of the bottle mouth to the inner depth, thereby effectively reducing the existence of gaps, improving the sealing performance, and reducing the possibility of leakage under high vacuum conditions. Attached Figure Description

[0017] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0018] Figure 1 This is a schematic diagram of the high vacuum push-pull valve of this utility model.

[0019] Explanation of reference numerals in the attached figures:

[0020] 1. Connector; 2. Vacuum stopper; 3. First sealing ring; 4. Valve body; 5. Bellows; 6. Valve stem; 7. Third sealing ring; 8. Clamp; 9. Plug; 10. Vacuum outlet; 11. Handle; 12. Second sealing ring. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0022] The principles and spirit of this utility model will be explained in detail below with reference to several representative embodiments.

[0023] Example 1 of the high vacuum push-pull valve provided by this utility model:

[0024] like Figure 1As shown, the high-vacuum push-pull valve includes a valve body 4, a valve stem 6, a bellows 5, and a vacuum stopper 2. A vacuum port 10 for connecting to a vacuum pumping device is provided on one side of the valve body 4, and the axis of the vacuum port 10 forms an acute angle with the axis of the valve body 4. The valve stem 6 is movably mounted inside the valve body 4 and can move up and down. The bellows 5 is coaxially sleeved on the valve stem 6, with its lower end welded to the valve stem 6 and its upper end connected to a plug 9 for sealing the valve body 4. The valve stem 6 passes through the plug 9 and slides with it in the vertical direction. A clamp 8 is provided outside the plug 9 to tighten it to the valve body 4. Both the clamp 8 and the plug 9 are existing technologies, and their structures will not be described in detail here. A first sealing ring 3 is provided between the valve body 4 and the plug 9, and the upper end of the valve body 4 is sealed by the first sealing ring 3 and the clamp 8.

[0025] The valve stem 6 is coaxial with the vacuum stopper 2, and the bottom of the valve stem 6 is threadedly connected to the vacuum stopper 2. A handle 11 perpendicular to the valve stem 6 is provided at the end of the valve stem 6 furthest from the vacuum stopper 2, making it easier for personnel to grip and reducing effort when pulling or pressing down the valve stem 6. The bottom of the valve body 4 has an internal thread for threaded engagement with the externally threaded connecting pipe 1. In this embodiment, the vacuum stopper 2 is shaped like an inverted frustum, with its diameter gradually decreasing from top to bottom. Three sealing grooves are spaced apart from top to bottom on the outer wall of the vacuum stopper 2, and a second sealing ring 12 is installed in each sealing groove. The distance between any two adjacent sealing grooves is equal. The connector 1 is a one-piece structure, comprising an integrally formed sealing pipe section and a connecting pipe section 1. The connecting pipe section 1 has external threads that mate with the internal threads of the valve body 4. The sealing pipe section has a tapered hole that matches the shape of the vacuum stopper 2. The minimum diameter of the tapered hole is larger than the diameter of the inner hole of the connecting pipe section 1, and the depth of the tapered hole is greater than the height of the vacuum stopper 2. The wall surface of the tapered hole is tapered, fitting tightly with the vacuum stopper 2. Three third sealing rings 7 are provided between the bottom of the inner wall of the valve body 4 and the outer wall of the connecting pipe section 1. The three third sealing rings 7 are equally spaced in the vertical direction and staggered from the second sealing rings 12 by a certain distance in the vertical direction.

[0026] The first sealing ring 3, the second sealing ring 12, and the third sealing ring 7 are all O-rings.

[0027] The high-vacuum push-pull valve of this utility model is used as follows:

[0028] In use, first weld the connector 1 to the interface of the container where vacuuming is required, then screw the valve body 4 onto the connector 1. At this time, the vacuum stopper 2 is inside the valve body 4 and not connected to the connector 1, meaning the inside of the connector 1 is in communication with the vacuum port 10. Then connect the vacuum unit to the vacuum port 10 and begin vacuuming. Once the required vacuum level is reached, press down the valve stem 6 to allow the vacuum stopper 2 to enter the connector 1, where it is sealed by three second sealing rings 12. Then remove the clamp 8, unscrew the valve stem 6 from the vacuum stopper 2, and remove the valve body 4 to complete the entire evacuation process.

[0029] As can be seen from the above process, the valve body 4 is directly connected to the connecting pipe 1, eliminating the steps of installing and removing the locking nut in the prior art. This results in fewer operation steps and higher efficiency during vacuuming. Furthermore, by using the inverted frustum-shaped vacuum stopper 2, when the stopper 2 is inserted downwards into the tapered connecting pipe 1 via the pull rod, the tapered shape causes the stopper 2 to experience uniform pressure from all directions of the interface. This uniform pressure distribution makes the contact between the stopper 2 and the connecting pipe 1 tighter, and the contact area between them gradually increases, ensuring a tight fit from the edge of the bottle opening to the inner depth. This effectively reduces the presence of gaps. Compared to the cylindrical grooved structure of the stopper 2, this improves sealing performance and reduces the possibility of leakage under high vacuum conditions.

[0030] In other embodiments, the number of sealing grooves on the vacuum bottle stopper can be reasonably designed according to its specific size, and is not limited to the three in the above embodiments. It can also be one, two or more.

[0031] In other embodiments, the depth of the conical hole within the connector may be equal to the height of the vacuum stopper. Of course, the depth of the conical hole within the connector may also be less than the height of the vacuum stopper.

[0032] In other embodiments, the sealing grooves on the vacuum bottle stopper can also be arranged at unequal intervals. When multiple sealing grooves are provided, the distance between two adjacent sealing grooves may be smaller than the distance between two other adjacent sealing grooves.

[0033] In the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

[0034] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A high-vacuum push-pull valve, comprising a valve body and a vacuum stopper movably mounted within the valve body via a valve stem, wherein the valve body is provided with a vacuum port for connection to a vacuum pumping device, characterized in that, The bottom of the valve body is provided with an internal thread for mating with the threaded connector with an external thread. The vacuum bottle stopper is in the shape of an inverted frustum, and the diameter of the vacuum bottle stopper gradually decreases from top to bottom. The inner wall of the connector opening is provided with a tapered surface that matches the outer circumferential surface of the vacuum bottle stopper. Sealing rings are provided between the inner wall of the valve body and the outer wall of the connector, and between the outer wall of the vacuum bottle stopper and the inner wall of the connector.

2. The high vacuum push-pull valve according to claim 1, characterized in that, The outer wall of the vacuum stopper is provided with multiple sealing grooves arranged at intervals from top to bottom, and each sealing groove is equipped with a sealing ring.

3. A high-vacuum push-pull valve according to claim 2, characterized in that, The spacing between any two adjacent sealing grooves is equal.

4. A high-vacuum push-pull valve according to claim 3, characterized in that, The sealing groove has three sections.

5. A high-vacuum push-pull valve according to any one of claims 1-4, characterized in that, The connector includes an integrally formed sealing pipe section and a connecting pipe section. The external thread is provided on the connecting pipe section. The sealing pipe section has a tapered hole inside. The wall surface of the tapered hole forms the tapered surface. The minimum diameter of the tapered hole is larger than the diameter of the inner hole of the connecting pipe section.

6. A high-vacuum push-pull valve according to claim 5, characterized in that, The depth of the conical hole is greater than the height of the vacuum stopper.

7. A high-vacuum push-pull valve according to any one of claims 1-4, characterized in that, The valve body is also provided with a bellows, which is sleeved on the valve stem and the lower end of the bellows is connected to the valve stem. The upper end of the bellows is connected to a plug for sealing the valve body. The valve stem and the plug are slidably assembled in the vertical direction. A clamp is provided on the outside of the plug for tightening the plug and the valve body. A sealing ring is also provided between the plug and the valve body.

8. A high-vacuum push-pull valve according to claim 6, characterized in that, The valve stem is coaxial with the vacuum stopper, and the bottom of the valve stem is threadedly connected to the vacuum stopper.

9. A high-vacuum push-pull valve according to claim 8, characterized in that, The valve stem has a handle rod perpendicular to the valve stem at the end furthest from the vacuum stopper.

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