A dead band free drain valve
By incorporating an embedded branch seat and flow channel filter design into the dead-zone-free condensate drain valve, the problems of liquid accumulation, freezing, cracking, corrosion, and blockage in traditional condensate drain valves in cold regions are solved, achieving dead-zone-free sealing of the medium and improving equipment safety and service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SINOPEC GUANGZHOU ENG CO LTD
- Filing Date
- 2025-08-05
- Publication Date
- 2026-08-04
AI Technical Summary
Traditional condensate drain valves create a dead zone at the lowest point of the pipeline when closed, preventing the complete drainage of accumulated liquid. This can easily lead to freezing and cracking in cold regions or blockage due to media corrosion and crystallization. Existing design standards lack comprehensive anti-freezing and insulation measures, posing safety hazards.
Design a dead-zone-free condensate drain valve, which adopts an embedded branch seat and valve body integral forging or casting, combined with a stuffing box, valve stem structure and flow channel filter screen, to ensure that the medium has no dead zone in the closed state, prevent liquid accumulation, and prevent impurities from entering through the filter screen, thereby enhancing sealing performance and structural stability.
It effectively avoids the risks of corrosion, blockage, and crystallization at the lowest points of the pipeline, reduces the difficulty of non-destructive testing, improves construction quality and safety, is suitable for cold regions and corrosive media environments, and reduces liquid retention time and the probability of crystallization.
Smart Images
Figure CN224592785U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of petrochemicals and relates to a mechanical valve technology, particularly suitable for use in the drainage sections of pipelines or equipment in cold regions, as well as for drainage valves at low points in pipelines or equipment containing highly corrosive, easily crystallizing, easily solidifying, or high-freezing-point media. When closed, this valve ensures no dead zone at the low point of the pipeline and includes a filter to prevent welding slag and rust from clogging the valve flow channel. Specifically, it relates to a dead-zone-free drainage valve. Background Technology
[0002] In piping systems, especially in industrial pipelines transporting liquids or gases, the function of low-point condensate drain valves is to remove accumulated liquid from the pipeline to prevent problems such as freezing, corrosion, or media crystallization. Traditional condensate drain valves create a dead zone at the lowest point of the pipeline when closed, preventing complete drainage. Under harsh climatic conditions, particularly in petrochemical plants in cold regions, this can easily lead to pipeline freezing and cracking at low temperatures, or blockages due to media corrosion and crystallization. Currently, there is no comprehensive set of guidelines in domestic design standards for equipment and pipeline anti-condensation and anti-freezing. Therefore, it is necessary to combine on-site design for each pipeline and equipment, focusing on the design methods and related precautions for process pipeline anti-freezing and insulation to ensure effective anti-freezing and insulation.
[0003] Safety accidents caused by this have occurred both domestically and internationally.
[0004] Domestic Case: For example, in a chemical company in northern China, the pipelines repeatedly froze and cracked in winter due to the failure to use dead-zone-free condensate drain valves, causing major safety accidents. This seriously affected the company's production safety and efficiency, as well as its social responsibility.
[0005] International Case: In a natural gas pipeline in the United States, the accumulation of liquid at the low point of the pipeline failed to be effectively drained, causing corrosive substances in the medium to remain for a long time, accelerating the corrosion process of the pipeline, and eventually causing a leak, resulting in serious personal injury and death.
[0006] Taking a DN20 pipeline condensate drain as an example, according to design specifications, the total length of the condensate accumulation zone before the drain valve, including the reinforced pipe joint, short pipe, and valve, is approximately 181mm. Based on feedback from owners in northern and northwestern China and on-site experience, freezing frequently occurs in the condensate accumulation zone before the drain valve, posing a significant threat to the safe operation of the plant. One of the key focuses of Sinopec's inspections of aging plants is to thoroughly inspect key areas such as pipeline blind ends, terminals, dead corners, and welded joints. However, this cannot fundamentally prevent freezing.
[0007] Furthermore, in petrochemical plants containing corrosive media or hydrogen, the use of embedded pipe supports has significant advantages over traditional fixed supports, especially in non-destructive testing, heat treatment, and hardness testing. Summary of the Invention
[0008] To address the problems existing in the prior art, especially in cold regions where pipelines or equipment are used to drain condensate or transport media containing highly corrosive, easily crystallizing, or easily solidifying media, or where the transported media are corrosive media such as those containing hydrogen sulfide, sulfur, acids, alkalis, etc., or viscous and easily crystallizing media such as asphalt, sulfur, coal powder, resin, etc., this invention can effectively eliminate the risk of corrosion, blockage, and crystallization at low points in pipelines. Therefore, this utility model provides a dead-zone-free condensate drain valve.
[0009] This utility model provides a dead-zone-free condensate drain valve, which includes a valve body, an embedded branch seat, a valve stem, a stuffing box, a stuffing gland, and a valve cover. The valve body and the embedded branch seat are integrally formed. The valve body is provided with a valve seat, an inlet flow channel, and an outlet flow channel. The embedded branch seat is connected to the condensate drain pipe or equipment. The valve stem is located at the center of the valve body and includes, from top to bottom, a valve head, an upper valve stem, a connector, a lower valve stem, and a valve cover. The valve head is located at the upper end of the upper valve stem. The upper valve stem and the lower valve stem are connected by the connector. The lower valve stem rises and falls with the upper valve stem, but the upper valve stem does not rotate with the lower valve stem to prevent rotation when the sealing surface of the valve head at the end of the upper valve stem contacts the sealing surface of the valve body and valve seat, thereby reducing the friction between the valve head and the valve seat. The valve head and valve seat engage to form a closed state, preventing the medium from entering the inlet flow channel. Furthermore, the upper surface of the valve head is basically flush with the inner surface of the process pipe or equipment, forming a theoretical dead-zone-free space.
[0010] A stuffing box is provided between the upper valve stem, the valve body, and the stuffing gland. Packing and packing spacers are placed inside the stuffing box, and the packing is tightened by the stuffing gland.
[0011] The valve body is also provided with an internal thread, the valve cover is provided with an internal thread and an external thread, and the lower valve stem is provided with an external thread. The external thread of the valve cover and the internal thread of the valve body cooperate to provide sealing force to the valve cover and to press the packing gland to compress the packing to form a seal. The internal thread of the valve cover and the external thread of the lower valve stem cooperate to allow the lower valve stem to move axially. The lower valve stem will rotate while moving axially.
[0012] The valve cover is also provided with a valve cover retaining ring and a valve cover retaining ring limiting screw to prevent the valve cover from loosening due to rotation. The valve cover retaining ring limiting screw is embedded in the valve body. A handle and a handle limiting screw are provided at the end of the lower valve stem for operating the valve. The handle limiting screw is embedded in the lower valve stem.
[0013] An outlet flow channel seal is installed in the outlet flow channel to form a second seal to prevent the medium from leaking to the outside under high pressure. The outlet flow channel seal includes an outlet flow channel flange, a gasket, an outlet flow channel flange cover, and fastening bolts. When the medium pressure is lower than 6.3MPa, the outlet flow channel seal can also be a threaded plug or a threaded pipe cap, provided that the design specifications are met.
[0014] An inlet flow channel filter and filter fixing screws are installed at the end of the inlet flow channel. The filter precision can be 30 mesh, or the precision can be adjusted according to the medium. This effectively prevents impurities such as welding slag and rust from entering the valve flow channel and damaging the valve sealing pair, thereby affecting the reliability of the seal and the normal operation of the valve. The filter fixing screws are embedded inside the valve body.
[0015] When the valve is open, the medium flows in from the inlet channel of the valve body and flows out from the outlet channel. The outlet channel seal forms a second seal to prevent the medium from leaking to the outside under high pressure.
[0016] The outlet flow channel is inclined downwards, forming a certain angle with the valve stem, with the optimal angle being 45° or 60°.
[0017] The upper valve stem and the lower valve stem are connected by a connector, which is a clamp.
[0018] The present invention has the following beneficial effects:
[0019] 1) The embedded branch pipe seat is integrally forged / cast with the valve body, and can also be butt-welded / flange connected. This avoids the fillet welds of traditional fixed supports, where radiographic and ultrasonic testing may be difficult to implement due to the geometry and location limitations of the fillet weld, potentially making welding defects difficult to detect. This reduces the difficulty of non-destructive testing and improves the quality of construction welding.
[0020] 2) When the embedded branch seat is forged / cast as an integral part of the valve body, the number of welds in the valve body can be reduced, thereby avoiding the generation of residual welding stress and reducing the risk of stress corrosion cracking; and reducing the area that needs to be heat treated for weld joints, thus reducing the difficulty of local heat treatment of the valve.
[0021] 3) Embedded pipe support welding can avoid the fillet welds of traditional placement supports, which is beneficial for hardness testing of butt welds (hardness testing of fillet welds is difficult). Traditional hardness testing methods may be difficult to apply to specific locations of fillet welds, which limits the accurate assessment of the actual hardness and material properties of the weld.
[0022] 4) Embedded pipe supports may have better structural stability than fixed supports, especially when subjected to large loads or in high temperature, high pressure environments, or in corrosive media or hydrogen environments. The fillet welds of fixed supports may be more susceptible to crevice corrosion and hydrogen-induced cracking. Attached Figure Description
[0023] Figure 1 This is a standard design structural diagram for a DN20, CL2500 condensate drain pipe.
[0024] Figure 2 This is a schematic diagram of the structure of the present invention in its closed state;
[0025] Figure 3 This is a schematic diagram of the structure of the present invention in the open state;
[0026] Figure 4 This is a schematic diagram of the valve body structure;
[0027] Figure 5 This is a schematic diagram of the valve cover structure;
[0028] Figure 6 This is a schematic diagram of the structure of the outlet flow channel seal;
[0029] Figure 7 This is a schematic diagram of the valve stem structure.
[0030] In the diagram: 1-Valve body 1, 111-Inlet flow channel, 112-Outlet flow channel, 113-Valve seat, 1131-Sealing surface, 114-Embedded branch seat, 115-Valve body internal thread, 2-Valve stem, 21-Upper valve stem, 211-Valve head, 2111-Valve head sealing surface, 22-Lower valve stem, 3-Stuffing gland, 31-Stuffing, 32-Stuffing septum, 4-Stuffing gland, 5-Valve cover, 6-Valve cover retaining ring, 61-Valve cover retaining ring limiting screw, 7-Handle, 71-Handle limiting screw, 8-Inlet flow channel filter screen, 81-Filter screen fixing screw, 9-Outlet flow channel seal, 91-Outlet flow channel flange, 92-Sealing gasket, 93-Outlet flow channel flange cover, 94-Fasting bolt. Detailed Implementation
[0031] The present invention will now be further described with reference to the accompanying drawings.
[0032] The present invention provides a dead-zone-free condensate drain valve comprising a valve body 1, an inlet flow channel 111, an outlet flow channel 112, a valve seat 113, an embedded branch seat 114, a valve stem 2, an upper valve stem 21, a valve head 211, a lower valve stem 22, a stuffing box 3, packing 31, a packing septum 32, a packing gland 4, a valve cover 5, a valve cover retaining ring 6, a valve cover retaining ring limiting screw 61, a handle 7, a handle limiting screw 71, an inlet flow channel filter screen 8, a filter screen fixing screw 81, an outlet flow channel seal 9, an outlet flow channel flange 91, a sealing gasket 92, an outlet flow channel flange cover 93, and fastening bolts 94. The embedded branch seat 114 and the valve body 1 can be integrally forged or cast, and the outlet flange 91 and the valve body 1 of the plunger valve can be integrally forged or cast, or they can be butt-welded or flanged.
[0033] The valve stem 2 consists of an upper valve stem 21, a lower valve stem 22, and an upper valve stem 5, which are connected by a compression fitting. When the lower valve stem 22 is raised, the upper valve stem 21 is also raised, but it does not rotate with the lower valve stem 22. This is to prevent the sealing surface 2111 of the valve head 211 at the end of the upper valve stem 21 from rotating when it comes into contact with the sealing surface 1131 of the valve body 1 valve seat 113, thereby increasing the friction between the valve head and the valve seat. The valve head 211 at the end of the upper valve stem 21 engages with the valve seat 113 of the valve body 1, forming a closed state, preventing the medium from entering the inlet flow channel 111 from the process pipeline 10. Furthermore, the upper end face of the valve head 211 is basically flush with the inner surface of the process pipeline 10, forming a theoretically dead-zone-free space. The valve head 211 and the valve seat 113 are hardened through a hardening process to increase their service life.
[0034] A stuffing box 3 is provided between the upper valve stem 21, the valve body 1, and the stuffing gland 4. The stuffing box 3 contains packing 31 and a packing septum 32, and the packing is tightened by the stuffing gland 4. The valve body 1 has an internal thread 115, the valve cover 5 has an internal thread 51 and an external thread 52, and the lower valve stem 22 has an external thread 221. The external thread 52 of the valve cover and the internal thread 115 of the valve body cooperate to provide sealing force to the stuffing gland 4, thereby tightening the packing 31 and forming a seal. The internal thread 51 of the valve cover and the external thread 221 of the lower valve stem cooperate to allow the lower valve stem 22 to move axially, and the lower valve stem 22 will rotate during axial movement. A valve cover retaining ring 6 and a valve cover retaining ring limiting screw 61 are provided at the valve cover 5 to prevent loosening due to rotation. The valve cover retaining ring limiting screw 61 is embedded in the valve body 1. The lower valve stem 22 is provided with a handle 7 and a handle limit screw 71 at its end for operating the valve. The handle limit screw 71 is embedded in the lower valve stem 22.
[0035] An outlet flow channel seal 9 is installed in the outlet flow channel to form a second seal, preventing the medium from leaking to the outside under high pressure. The outlet flow channel seal 9 includes an outlet flow channel flange 91, a sealing gasket 92, an outlet flow channel flange cover 93, and fastening bolts 94. When the medium pressure is lower than 6.3MPa, the outlet flow channel seal 9 can also be replaced by a threaded plug, a threaded cap, or omitted according to the design / customer requirements, provided that the design specifications are met.
[0036] An inlet flow channel filter screen 8 and a filter screen fixing screw 81 are provided at the end of the inlet flow channel 111. The filter screen precision can be 30 mesh, and the precision can also be adjusted according to the medium conditions. This effectively prevents impurities such as welding slag and rust from entering the valve flow channel and damaging the valve sealing pair, thereby affecting the reliability of the seal and the normal operation of the valve. The filter screen fixing screw 81 is embedded inside the valve body 1.
[0037] When the valve is open, the medium flows in from the inlet channel 111 of the valve body 1 and flows out from the outlet channel 112. The outlet channel seal 9 forms a second seal to prevent the medium from leaking to the outside under high pressure. The outlet channel seal 9 includes an outlet channel flange 91, a gasket 92, an outlet channel flange cover 93, and fastening bolts 94.
[0038] This invention features a compact structure, making it particularly suitable for applications with limited space at the bottom of process pipelines and equipment. For example, a conventional design for a DN20, CL2500 condensate drain pipe includes a reinforced pipe joint, short pipe, valve, and flange + flange cover, with a structural dimension of approximately 370mm, including a dead zone length of about 201mm where liquid tends to accumulate. The dead zone-free low-point condensate drain valve provided in this embodiment has a structural length of 254.6mm when the valve is open, resulting in a more compact structure and easier installation. When the valve is closed, its dead zone length is essentially zero, preventing liquid accumulation at the low point and fundamentally avoiding liquid buildup. This also prevents freezing and cracking of the condensate drain section in cold regions. This valve is also suitable for corrosive media such as those containing hydrogen sulfide, sulfur, acid, or alkali, or viscous, easily crystallizing media such as asphalt, sulfur, coal powder, and resin, effectively eliminating the risks of corrosion, blockage, and crystallization at the low point of the pipeline. In particular, when the valve is open, the distance that the medium flows through the valve channel to the outside of the pipeline is only half that of the conventional design. The shortened distance means that it can be used for rapid drainage of condensate and reduce the residence time of accumulated liquid. For viscous or easily crystallizing media, the probability of solidification and crystallization is greatly reduced.
[0039] This invention can be used for draining condensate from the bottom of pipes or from the bottom of equipment.
[0040] The above description is merely a typical embodiment of this utility model and does not impose any limitations on this utility model. Any changes or modifications made by those skilled in the art using the above content without departing from the scope of the technical solution of this utility model should be considered equivalent examples of equivalent changes. Any equivalent changes made to the above embodiments based on the technical essence of this utility model without departing from the content of the technical solution of this utility model shall fall within the scope of the technical solution of this utility model.
Claims
1. A dead band free let down valve characterized by: The condensate drain valve includes a valve body, an embedded branch seat, a valve stem, a stuffing box, a stuffing gland, and a valve cover. The valve body and the embedded branch seat are integrally formed. The valve body contains a valve seat, an inlet flow channel, and an outlet flow channel. The embedded branch seat is connected to the condensate drain pipe or equipment. The valve stem is located at the center of the valve body and includes, from top to bottom, a valve head, an upper valve stem, a connector, a lower valve stem, and a valve cover. The valve head is located at the upper end of the upper valve stem. The upper valve stem and the lower valve stem are connected by a connector. The lower valve stem rises and falls with the upper valve stem. The valve head engages with the valve seat to form a closed state. The upper surface of the valve head is basically flush with the inner surface of the process pipe or equipment.
2. The dead band free let down valve of claim 1, wherein: A stuffing box is provided between the upper valve stem, the valve body, and the stuffing gland. Packing and packing spacers are placed inside the stuffing box, and the packing is tightened by the stuffing gland.
3. The dead band free let down valve of claim 1, wherein: The valve body is also provided with an internal thread, the valve cover is provided with an internal thread and an external thread, and the lower valve stem is provided with an external thread. The external thread of the valve cover and the internal thread of the valve body cooperate to provide sealing force to the valve cover and to press the packing gland to compress the packing to form a seal. The internal thread of the valve cover and the external thread of the lower valve stem cooperate to allow the lower valve stem to move axially. The lower valve stem will rotate while moving axially.
4. The dead-zone-free condensate drain valve according to claim 1, characterized in that: The valve cover is also provided with a valve cover retaining ring and a valve cover retaining ring limiting screw to prevent the valve cover from loosening due to rotation. The valve cover retaining ring limiting screw is embedded in the valve body. A handle and a handle limiting screw are provided at the end of the lower valve stem for operating the valve. The handle limiting screw is embedded in the lower valve stem.
5. The dead-zone-free condensate drain valve according to claim 1, characterized in that: An outlet flow channel seal is provided to form a second seal to prevent the medium from leaking to the outside under high pressure. The outlet flow channel seal includes an outlet flow channel flange, a gasket, an outlet flow channel flange cover, and fastening bolts. When the medium pressure is lower than 6.3 MPa, the outlet flow channel seal is a threaded plug or a threaded cap.
6. The dead-zone-free condensate drain valve according to claim 1, characterized in that: An inlet channel filter and filter fixing screws are provided at the end of the inlet channel, and the filter precision is 30-50 mesh.
7. The dead-zone-free condensate drain valve according to claim 1, characterized in that: When the condensate drain valve is open, the medium flows in from the inlet channel of the valve body and flows out from the outlet channel. The outlet channel seal forms a second seal to prevent the medium from leaking to the outside under high pressure.
8. The dead-zone-free condensate drain valve according to claim 1, characterized in that: The upper valve stem and the lower valve stem are connected by a connector, which is a clamp.
9. The dead-zone-free condensate drain valve according to claim 1, characterized in that: The outlet flow channel is inclined downwards, forming a certain angle with the valve stem.
10. The dead-zone-free condensate drain valve according to claim 1, characterized in that: The angle between the outlet flow channel and the valve stem is 45 0 or 60 0 .