A bellows valve for an ultra-pure ammonia plant

Abstract

The utility model relates to a corrugated pipe valve for ultrapure ammonia device, including valve body, valve seat, gland, valve rod and valve core, the first corrugated pipe is welded between valve core and valve body inner chamber upper end, the inner screw bush is welded in the lower part of gland, the valve rod passes through the gland and inner screw bush and is with inner screw bush screw thread cooperation, the second corrugated pipe is welded between valve core and and inner screw bush. The utility model relates to a corrugated pipe valve for ultrapure ammonia device novel structure, reasonable in design, the overall structure is more stable, improves the isolation effect to valve rod, and the valve is more stable in actual use, reduces the failure rate of valve, reduces the risk of leakage, prolongs the life, realizes the visual monitoring of the scene, helps the scene operator to find the leakage in time and handles, thereby improves the product pass rate and guarantees smooth production.

Description

Technical Field

[0001] This utility model relates to the field of bellows valves, and in particular to a bellows valve for an ultrapure ammonia plant. Background Technology

[0002] In the actual production process of ultrapure ammonia production, the raw material ammonia used for production is strictly required to achieve a purity of 7N through refining and distillation. This process must be carried out with zero leakage and zero pollution. Bellows valves are used on the ultrapure ammonia unit (i.e., ultrapure ammonia conveying pipeline and ultrapure ammonia equipment) to complete the distillation.

[0003] In actual use, this type of valve uses a bellows structure to completely isolate the valve stem from the material, preventing external contaminants from entering the valve and contaminating the medium through the gaps between the valve stem and the sealing packing, and also preventing qualified medium from leaking to the outside through the gaps between the valve stem and the packing.

[0004] Through actual statistics and investigation of valves of this type used in the plant, it was found that the bellows of these valves are generally designed with a single-layer bellows structure. In actual use, the bellows undergoes axial tension and compression along with the valve stem. Its weak points are subjected to repeated tensile and compressive stress, resulting in fatigue failure and microcracks. During the pipeline transportation process, pressurized medium enters the inside of the bellows through microcracks and escapes to the outside through the gap between the valve stem and the packing, causing leakage. When inspection personnel discover the leakage on site, they often miss the opportunity to seal the pipeline valves in time to prevent contamination of qualified products in the pipeline. The leakage also causes contaminants located at the valve stem and inside the bellows to be successfully carried into the pipeline and mix with the products, destroying the original cleanliness of the products and thus reducing the product qualification rate. Frequent valve leakage and replacement directly affect the stable production of the plant and the product qualification rate. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a bellows valve for ultrapure ammonia plants, which has a more stable overall structure, reduces valve failure rate, lowers leakage risk, and extends service life.

[0006] This utility model is implemented using the following scheme: a bellows valve for an ultrapure ammonia unit, comprising a valve body, a valve seat, a gland, a valve stem, and a valve core. A first bellows is welded between the valve core and the upper end of the valve body cavity. An inner threaded sleeve is welded to the lower part of the gland. The valve stem passes through the gland and the inner threaded sleeve and is threadedly engaged with the inner threaded sleeve. A second bellows is welded between the valve core and the inner threaded sleeve.

[0007] Furthermore, a sealed cavity is formed between the gland and the second corrugated pipe and the first corrugated pipe. A pressure transmission channel is provided on the gland, with one end extending through the outer side and the other end extending through the bottom surface and communicating with the sealed cavity.

[0008] Furthermore, the pressure transmission channel is connected to a detection pipe at its outward end. The detection pipe is equipped with a vacuum pressure gauge and a needle valve, and a plug is provided at the end of the detection pipe.

[0009] Furthermore, a handwheel is connected to the upper end of the valve stem by screws.

[0010] Furthermore, the valve stem is rotatably and slidably fitted with the gland, and an annular rubber pad is provided at the center hole at the upper end of the gland, through which the valve stem passes.

[0011] Furthermore, the gland is connected to the upper end of the valve body by several bolts.

[0012] Compared with the prior art, the present invention has the following advantages: The bellows valve structure of the present invention for ultrapure ammonia unit is novel and reasonably designed, with a more stable overall structure, improving the isolation effect on the valve stem, making the valve more stable in actual use, reducing the valve failure rate, reducing the risk of leakage, and extending the service life; it realizes on-site visual monitoring, helping on-site operators to detect and deal with leaks in a timely manner, thereby improving the product qualification rate and ensuring stable production.

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below through specific embodiments and related drawings. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model; The labels in the diagram are as follows: 1-Gland, 2-Vacuum pressure gauge, 3-Needle valve, 4-Plug, 5-Pressure transmission channel, 6-Valve body, 7-First bellows, 8-Second bellows, 9-Valve core, 10-Valve seat, 11-Handwheel, 12-Rubber pad, 13-Bolt, 14-Valve stem, 15-Internal threaded sleeve, 16-Screw. Detailed Implementation

[0015] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0017] like Figure 1 As shown, a bellows valve for an ultrapure ammonia unit includes a valve body 6, a valve seat 10, a gland 1, a valve stem 14, and a valve core 9. The valve seat 10 is located at the lower part of the valve body 6 and is used to cooperate with the valve core to achieve on / off switching. A first bellows 7 is welded between the upper end of the inner cavity of the valve core 9 and the valve body 14. An inner threaded sleeve 15 is welded to the lower part of the gland 1. The valve stem 14 passes through the gland 1 and the inner threaded sleeve 15 and is threadedly engaged with the inner threaded sleeve. The upper half of the valve stem 14 is a smooth shaft, and the lower half is an externally threaded rod. A second bellows 8 is welded between the valve core 9 and the inner threaded sleeve 15. The first bellows provides primary sealing, and the second bellows 8 provides secondary sealing, making the overall structure of the valve more stable during actual use and operation, improving the isolation effect on the valve stem, and making the valve more stable in actual use. Increasing the stress distribution of the second bellows reduces the structural stress on the original bellows (i.e., the first bellows), thus extending the actual service life of the valve.

[0018] In this embodiment, a sealed cavity is formed between the pressure cap 1 and the second corrugated pipe 8 and the first corrugated pipe 7. A pressure transmission channel 5 is provided on the pressure cap 1, with one end penetrating the outer side and the other end penetrating the bottom surface and communicating with the sealed cavity.

[0019] In this embodiment, a detection pipe is connected to the outward end of the pressure transmission channel 5. A vacuum pressure gauge 2 and a needle valve 3 are mounted on the detection pipe. The vacuum pressure gauge 2 is connected to the detection pipe via a tee. The detection pipe is connected to the outward end of the pressure transmission channel 5 via a quick connector. A plug 4 is provided at the end of the detection pipe. The plug 4 is a single-threaded plug, with an external thread at the end of the detection pipe and an internal thread at the end. After the valve is evacuated, the plug is installed at the end of the detection pipe for sealing via the threaded connection. The pressure transmission channel 5 serves as a pressure measurement channel, connecting the pressure monitoring equipment (including the detection pipe, vacuum pressure gauge 2, needle valve 3, plug 4, tee, and quick connector) to the sealed cavity. After installation, a slightly negative pressure vacuum environment can be created within the sealed cavity by evacuation.

[0020] The newly added pressure monitoring equipment is made of the same material as the original, using 316L stainless steel, to ensure that the overall material of the valve is consistent with the original material, and to avoid galvanic corrosion, i.e., the galvanic cell effect, caused by the inconsistency between the two materials.

[0021] In this embodiment, a handwheel 11 is connected to the upper end of the valve stem 14 by a screw 16.

[0022] In this embodiment, the valve stem 14 is rotatably and slidably engaged with the pressure cap 1. An annular rubber pad 12 is provided at the center hole at the upper end of the pressure cap, and the valve stem 14 passes through the middle of the rubber pad 12.

[0023] In this embodiment, the pressure cap 1 is connected to the upper end of the valve body 6 by a number of bolts 13.

[0024] This invention upgrades and modifies the existing bellows valve (mainly by adding a pressure detection and display function and adding a new, smaller bellows, i.e., a second bellows). The structure and dimensions of the original bellows (i.e., the first bellows) remain unchanged. The stress condition of the bellows is improved, and by adding accessories, valve leakage can be visualized through pressure fluctuations. This solves the problems of short service life and inability to detect leakage in the first instance for this type of valve, greatly improving the valve's service life and monitorability.

[0025] The design maintains the original shape and size, without the need to adjust or change other parts of the valve. It can be directly replaced during actual use, the overall modification cost is controllable, and the operation is convenient.

[0026] By optimizing and improving the structure, adding a set of bellows reduces the structural stress on the original bellows, significantly improves their fatigue resistance, extends the valve's service life, and provides dual protection. In the event of a leak in the large bellows, the small bellows acts as a second seal to isolate the medium from the external environment. Furthermore, the addition of pressure monitoring enables on-site visual monitoring of the valve during operation. By observing changes in the vacuum pressure gauge readings, operators can promptly detect and address leaks, reducing valve failure rates, mitigating leakage risks, and ultimately improving product qualification rates and ensuring stable production.

[0027] The usage process of this bellows valve is as follows: After assembling the bellows valve, open the needle valve and use a vacuum pump to evacuate the air from the sealed cavity inside the valve, creating a slightly negative pressure environment. Then close the needle valve and maintain the pressure for 30 minutes to observe any pressure changes, thus determining whether the bellows is leaking. During actual operation, operators can directly check the readings of the vacuum pressure gauge to determine the actual condition of the bellows. When the gauge reading is 0 or a positive value, it indicates that the first bellows at the valve core has been damaged. In this case, the second bellows acts as a second seal, locking the medium inside the valve core to prevent leakage to the external environment, thus allowing more time for preparing spare parts and for downtime replacement.

[0028] Unless otherwise stated, if any of the technical solutions disclosed in this utility model discloses a numerical range, then the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this utility model discloses only some numerical values ​​to illustrate the technical solutions of this utility model. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this utility model.

[0029] If this utility model discloses or relates to mutually fixedly connected parts or structural components, then unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured by integral molding using a casting process) (except where it is obviously impossible to use an integral molding process).

[0030] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this utility model above include states or shapes that are similar to, close to, or approximate with them.

[0031] Any component provided by this utility model can be assembled from multiple individual components, or it can be a single component manufactured by a one-piece molding process.

[0032] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A bellows valve for an ultrapure ammonia unit, comprising a valve body, a valve seat, a gland, a valve stem, and a valve core, characterized in that: A first bellows is welded between the valve core and the upper end of the valve body cavity, and an inner threaded sleeve is welded to the lower part of the gland. The valve stem passes through the gland and the inner threaded sleeve and is threadedly engaged with the inner threaded sleeve. A second bellows is welded between the valve core and the inner threaded sleeve.

2. The bellows valve for an ultrapure ammonia unit according to claim 1, characterized in that: The pressure cap and the second corrugated pipe form a sealed cavity with the first corrugated pipe. The pressure cap has a pressure transmission channel with one end extending through the outer side and the other end extending through the bottom surface and connecting to the sealed cavity.

3. The bellows valve for an ultrapure ammonia unit according to claim 2, characterized in that: The pressure transmission channel is connected to a detection pipe at its outward end. The detection pipe is equipped with a vacuum pressure gauge and a needle valve, and a plug is provided at the end of the detection pipe.

4. The bellows valve for an ultrapure ammonia unit according to claim 1, characterized in that: A handwheel is connected to the upper end of the valve stem by screws.

5. The bellows valve for an ultrapure ammonia unit according to claim 1, characterized in that: The valve stem is rotatably and slidably fitted with the gland, and an annular rubber pad is provided at the center hole at the upper end of the gland, through which the valve stem passes.

6. The bellows valve for an ultrapure ammonia unit according to claim 1, characterized in that: The gland is connected to the upper end of the valve body by several bolts.

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