A high-efficiency series boiler blowdown valve

Abstract

This utility model discloses a high-efficiency series-connected boiler blowdown valve, relating to the field of valve technology. It includes a valve body with a first valve stem channel and a second valve stem channel within it. A flow channel pipe connects the first and second valve stem channels. A first valve disc is slidably disposed within the first valve stem channel, and a first valve stem is disposed within the first valve stem channel. The first valve stem is fixedly connected to the first valve stem. A second valve disc is slidably disposed within the second valve stem channel, and a second valve stem is disposed within the second valve stem channel. The second valve disc is slidably connected to the second valve stem. An upward-opening groove is provided on the second valve disc, and the second valve stem is slidably disposed within the groove. The design employs a series connection of a stop valve and a stop check valve, effectively reducing the erosion of the valve body components by high-pressure gas.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, specifically to a high-efficiency series boiler blowdown valve. Background Technology

[0002] During boiler operation, impurities in the water, such as sludge and scale, gradually settle at the bottom of the boiler. If these impurities are not removed in time, they will affect the boiler's heat transfer efficiency. Scale has a much lower thermal conductivity than metal, preventing heat from being effectively transferred from the boiler's heating surfaces to the boiler water, thus reducing the boiler's evaporation efficiency. Boiler water contains various minerals and salts; during continuous evaporation and concentration, the salt content and alkalinity of the boiler water gradually increase. Regular blowdown can reduce the salt content, alkalinity, and hardness of the boiler water, preventing steam-water bubbling. Steam-water bubbling causes water to be carried over into the steam, reducing steam quality and potentially leading to safety hazards such as water hammer in steam pipes. Some impurities and high concentrations of chemicals can cause corrosion of the boiler's metal components. Regular blowdown can reduce these harmful components and extend the boiler's service life.

[0003] During boiler blowdown, the high flow rate of water causes erosion of the valve's internal components, especially the valve seat and valve disc sealing surfaces. Domestically produced boiler blowdown valves generally employ a gate valve or tandem gate valve structure. In a single gate valve structure, the high-pressure steam erosion of the valve's internal components leads to defects such as pitting, resulting in loss of sealing and necessitating premature repair or replacement. In a tandem gate valve structure, the gate valve closest to the boiler must be opened first, followed by the other. When the gate valve closest to the boiler is opened, the medium erodes the valve's internal components, affecting their lifespan. Once the blowdown valve closest to the boiler is fully open (gate valves only have open and closed states during operation), the steam medium completely fills the cavity between the two tandem gate valves. Opening the other gate valve simply repeats the function of the previous gate valve without effective protection. Therefore, these two gate valves have overlapping functions and do not address the erosion effect of high-pressure steam on the valve's internal components at small openings. Utility Model Content

[0004] Purpose of the utility model: The technical problem to be solved by this utility model is to provide a high-efficiency series boiler blowdown valve, which solves the problem that the internal parts of the existing blowdown valve are easily washed away by sewage.

[0005] Technical solution

[0006] To solve the above problems, the technical solution provided by this utility model is as follows:

[0007] A high-efficiency series-connected boiler blowdown valve includes a valve body. The valve body contains a first valve stem channel and a second valve stem channel, connected by a flow channel pipe. A first valve disc is slidably disposed within the first valve stem channel, and a first valve stem is disposed within the first valve stem channel. The first valve stem is fixedly connected to the first valve stem. A second valve disc is slidably disposed within the second valve stem channel, and a second valve stem is disposed within the second valve stem channel. The second valve disc is slidably connected to the second valve stem. The second valve disc has an upward-opening groove, and the second valve stem is slidably disposed within the groove.

[0008] Furthermore, a drain pipe is connected to the bottom of the first valve stem channel, and the first valve disc blocks the interface between the first valve stem channel and the drain pipe. The interface between the first valve stem channel and the drain pipe is lower than the interface between the first valve stem channel and the flow channel pipe.

[0009] Furthermore, the second valve stem channel is a variable diameter pipe, which includes an upper pipe and a lower pipe. The inner diameter of the upper pipe is larger than the inner diameter of the lower pipe, and the flow channel is connected to the lower pipe.

[0010] Furthermore, a final discharge pipe is connected to the side of the second valve stem channel, the final discharge pipe is connected to the upper pipe, and the second valve disc blocks the interface between the upper pipe and the lower pipe.

[0011] Furthermore, the sewage pipe is a tapered pipe, and the inner diameter of the sewage pipe gradually decreases as it approaches the first valve stem channel.

[0012] Furthermore, the flow channel is a U-shaped pipe, and the inner diameter of the middle section of the flow channel increases outward.

[0013] Furthermore, both the first valve disc and the second valve disc have a conical structure.

[0014] Furthermore, the valve body is provided with valve covers corresponding to the first valve stem and the second valve stem. The valve covers are provided with packing grooves. The first valve stem and the second valve stem pass through the packing grooves. Packing is provided between the packing grooves and the first valve stem and the second valve stem. A packing gland is pressed onto the packing and is fixed to the valve covers.

[0015] Furthermore, the valve cover is provided with a valve stem nut, and a double-headed column is fixed between the valve stem nut and the valve cover. A threaded upper valve stem is rotatably provided inside the valve stem nut. The threaded upper valve stem is threadedly engaged with the valve stem nut. A handwheel is fixedly provided on the threaded upper valve stem. Anti-rotation blocks are respectively provided between the threaded upper valve stem and the first valve stem and the second valve stem.

[0016] Furthermore, a sealing gasket is provided on the valve cover or the valve body.

[0017] Beneficial effects

[0018] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0019] The system employs a series connection of a gate valve and a gate check valve. During the opening process of the gate valve near the boiler, as long as the steam medium pressure in the flow channel exceeds the weight of the gate check valve disc, the valve disc will open. At low pressures, the disc opens, reducing the erosion of the valve internals by the steam medium and extending the valve's service life. When the gate valve near the boiler fails to seal, turning the handwheel of the gate check valve clockwise will close it, effectively reducing the erosion of the valve internals by high-pressure gas.

[0020] A flow channel is designed in the middle section of the gate valve and the gate check valve. This flow channel adopts a U-shaped tube structure, which increases the number of bends of the steam medium in the flow channel, increases the flow resistance, and increases the pressure loss of the steam medium in the flow channel. An enlarged diameter section is designed in the middle section, which increases the flow resistance of the steam medium and reduces the flow velocity of the steam medium. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0022] Figure 2 This is a schematic diagram of another aspect of the structure of Embodiment 1 of this utility model;

[0023] Figure 3 This is a cross-sectional view of Embodiment 1 of the present utility model;

[0024] Figure 4 This is a cross-sectional view of the shut-off valve and flow channel pipe of Embodiment 1 of this utility model;

[0025] Figure 5 This is a cross-sectional view of the shut-off check valve and flow channel pipe in Embodiment 1 of this utility model;

[0026] Figure 6 This is a cross-sectional view of the flow channel tube in Embodiment 1 of this utility model.

[0027] 1. Valve body; 2. First valve disc; 3. First valve stem; 4. Valve cover; 5. Packing; 6. First valve stem passage; 7. Packing gland; 8. Anti-rotation block; 9. Threaded upper valve stem; 10. Valve stem nut; 11. Handwheel; 12. Second valve stem passage; 13. Second valve disc; 14. Second valve stem; 15. Double-ended column; 16. Flow channel pipe; 17. Final discharge pipe; 18. Sewage pipe; 19. Upper passage; 20. Lower passage; 30. Gate valve; 40. Gate check valve; Detailed Implementation

[0028] To make the technical solution of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] Combined with appendix Figure 1-6 A high-efficiency series-connected boiler blowdown valve is composed of a stop valve 30 and a stop check valve 40. The stop valve 30 and the stop check valve 40 share a single valve body 1. The valve body 1 has the structure of the stop valve 30 on one side and the structure of the stop check valve 40 on the other. Two valve stem channels are arranged in parallel on the valve body 1, namely a first valve stem channel 6 and a second valve stem channel 12. For ease of explanation, the relevant structures of the stop valve 30 are referred to as "first" matching structures. The relevant structures of the stop check valve 40 are referred to as "second" matching structures.

[0031] The bottom of the first valve stem passage 6 is connected to a drain pipe 18, which is a tapered pipe. The inner diameter of the drain pipe 18 gradually decreases as it approaches the first valve stem passage 6. The inner diameter of the end of the drain pipe 18 where it connects to the first valve stem passage 6 is also smaller than the inner diameter of the first valve stem passage 6. This increases the pressure loss of high-pressure steam as it passes through the drain pipe 18 by changing the flow rate of the steam flowing in the drain pipe 18 and by reducing energy consumption.

[0032] A first valve disc 2 is slidably disposed within the first valve stem channel 6. The first valve disc 2 can completely block the connection between the sewage pipe 18 and the first valve stem channel 6. By raising and lowering the first valve disc 2, the connection and disconnection between the sewage pipe 18 and the first valve stem channel 6 can be controlled. Since the inner diameter of the top end of the sewage pipe 18 is smaller than the inner diameter of the bottom end of the first valve stem channel 6, the first valve disc 2, which slides within the first valve stem channel 6, can block the opening connecting the first valve stem channel 6 and the sewage pipe 18.

[0033] A flow channel 16 is provided between the first valve stem channel 6 and the second valve stem channel 12. The flow channel 16 is used to guide the high-pressure steam in the first valve stem channel 6 to the second valve stem channel 12. The opening of the flow channel 16 connecting with the first valve stem channel 6 is located above the opening connecting the first valve stem channel 6 with the sewage pipe 18. The connection between the flow channel 16 and the sewage pipe 18 is controlled by the rise and fall of the first valve disc 2. That is, when the first valve disc 2 abuts against the opening connecting the first valve stem channel 6 and the sewage pipe 18, the flow channel 16 and the sewage pipe 18 are isolated from each other. After the first valve disc 2 rises, the flow channel 16 connects with the sewage pipe 18. At this time, the high-pressure steam in the sewage pipe 18 can flow into the flow channel 16.

[0034] The flow channel 16 adopts a U-shaped tube structure, which increases the number of bends of the steam medium within the flow channel 16, increases flow resistance, and increases pressure loss of the steam medium within the flow channel 16. The inner diameter of the middle section of the flow channel 16 is widened outward. By locally increasing the diameter section of the flow channel 16, the flow resistance of the steam medium is increased, and the flow velocity of the steam medium is reduced.

[0035] Since the first valve disc 2 requires a sliding process to achieve the transition from isolation to connection between the flow pipe and the sewage pipe 18, the size of the first valve disc 2 should be able to completely block the opening connecting the flow channel pipe 16 and the first valve stem channel 6. This prevents high-pressure steam from overflowing from the opening connecting the sewage pipe 18 and the first valve stem channel 6 during the initial rise of the first valve disc 2. Part of the high-pressure steam enters the flow channel pipe 16, while the other part bypasses the flow channel pipe 16 and enters the space above the flow pipe in the first valve stem channel 6. The high-pressure steam converges in the space of the first valve stem channel 6 above the flow channel pipe 16, thereby affecting the opening of the first valve disc 2 and preventing the high-pressure steam from corroding the valve disc, valve stem, and other components.

[0036] A second valve disc 13 is slidably disposed within the second valve stem channel 12. The second valve disc 13 is used to block the second valve stem channel 12. The second valve disc 13 is located above the opening where the second valve stem channel 12 connects to the flow channel pipe 16. A final discharge pipe 17 is disposed on the side of the second valve stem channel 12. The final discharge pipe 17 is located above the second valve stem channel 12 and the flow channel pipe 16. The second valve disc 13 achieves communication and isolation between the flow channel pipe 16 and the final discharge pipe 17 by switching between blocking the second valve stem channel 12. The second valve stem channel 12 is a variable diameter pipe. The inner diameter of the upper channel 19 of the second valve stem channel 12 is larger than the inner diameter of the lower channel 20 of the second valve stem channel 12. The second valve disc 13 slides within the upper channel 19 of the second valve stem channel 12. Since the inner diameter of the upper channel 19 of the second valve stem channel 12 is larger than the inner diameter of the lower channel 20, the second valve disc 13 can block the interface connecting the upper channel 19 and the lower channel 20 of the second valve stem channel 12.

[0037] The second valve stem passage 12 is connected to a final discharge pipe 17 on its side. The final discharge pipe 17 is connected to the upper passage 19 of the second valve stem passage 12, and the flow channel pipe 16 is connected to the lower passage 16 of the second valve stem passage 12. The connection between the final discharge pipe 17 and the flow channel pipe 16 is switched by the movement of the second valve disc 13 within the second valve stem passage 12. When the second valve disc 13 is located at the interface between the upper passage 19 and the lower passage 20 of the second valve stem passage 12, the final discharge pipe 17 is isolated from the flow channel pipe 16. When the second valve disc 13 moves from the second valve stem passage 12, the final discharge pipe 17 is isolated from the flow channel pipe 16. After rising at the interface between the upper channel 19 and the lower channel 20 of the rod channel 12, the final discharge pipe 17 connects with the flow channel pipe 16. At the same time, the size of the second valve disc 13 is also able to completely block the opening connecting the final discharge pipe 17 and the second valve rod channel 12, preventing a portion of the high-pressure steam in the flow channel pipe 16 from crossing the final discharge pipe 17 and moving into the space above the second valve disc 13 in the second valve rod channel 12 during the rising process of the second valve disc 13. This also prevents the high-pressure steam from affecting the opening of the second valve disc 13 and from corroding the valve disc, valve rod, and other components.

[0038] A first valve stem 3 is provided in the first valve stem channel 6. The bottom of the first valve stem 3 is fixedly connected to the first valve disc 2. The first valve stem 3 drives the first valve disc 2 to slide up and down in the first valve stem channel 6. The structure of the first valve disc 2 is preferably a cone or frustum-shaped cone. The first valve disc 2 extends into the interface between the first valve stem channel 6 and the sewage pipe 18 to achieve blockage. A limiting groove can be provided on the first valve disc 2. The bottom of the first valve stem 3 is provided with a matching structure corresponding to the limiting groove on the first valve disc 2, thereby opening and closing the first valve stem 3 and the first valve disc 2. Other connection methods include, but are not limited to, threaded connection, pin connection, and welding, etc.

[0039] The second valve stem passage 12 is provided with a second valve stem 14, and the second valve disc 13 is also a conical or frustum-shaped structure. The second valve disc 13 extends into the interface connecting the upper channel 19 and the lower channel 20 of the second valve stem passage 12 to achieve blockage. The second valve stem 14 and the second valve disc 13 are in a sliding fit. The second valve disc 13 is provided with an upward-opening groove. The second valve stem 14 extends into the groove on the second valve disc 13, and the second valve disc 13 slides relative to the second valve stem 14 through the groove. When the second valve stem 14 is stationary, the second valve disc 13 slides up and down at the bottom of the second valve stem 14. The second valve stem 14 is provided with an abutment ring on the upper side of the second valve disc 13. When the second valve stem 14 is in the extreme position in the groove, the abutment ring on the second valve stem 14 abuts against the second valve disc 13. The second valve stem 14 can push the second valve disc 13 to slide downward through the abutment ring abutting against the top surface of the second valve disc 13 and the abutment of the bottom end of the second valve stem 14 against the inner wall of the bottom of the groove.

[0040] The second valve disc 13 is designed with a conical arc structure. At a small opening, it acts as a guide, reducing the scouring effect of the steam medium on the second valve disc 13. At a large opening, in conjunction with the rising and falling height of the valve stem, it can act as a throttling device. The second valve disc 13 utilizes a dual guiding effect from the inner wall of the second valve stem channel 12 and the shape of the valve stem to prevent the second valve disc 13 from shifting and improve its stability. The sliding groove of the second valve disc 13 can be designed as a "plum blossom-shaped hole" to further stabilize the second valve disc 13. While fulfilling its guiding function, it can also quickly discharge high-pressure steam at the interface of the upper channel 19 and lower channel 20 of the second valve stem channel 12, allowing the second valve disc 13 to rise and fall rapidly.

[0041] Both the first valve stem 3 and the second valve stem 14 are equipped with structures for driving their up-and-down movement. Both extend from the valve body 1. A valve cover 4 is located at the top of the valve body 1, corresponding to the positions of the first valve stem 3 and the second valve stem 14. The valve cover 4 is fixed to the valve body 1 with bolts. The first valve stem 3 and the second valve stem 14 slide within their respective valve covers 4. A packing groove is provided within the valve cover 4. Both the first valve stem 3 and the second valve stem 14 are inserted into the packing groove and pass through the valve cover 4. A gap is provided between the inner wall of the packing groove of the valve cover 4 and the first valve stem 3 and the second valve stem 14. A gap is also provided between the inner wall of the packing groove of the valve cover 4 and the first valve stem 3 and the second valve stem 14. The gap between the rods 14 is filled with packing material 5. A packing gland 7 is provided at the opening of the gap between the side wall of the packing groove and the gap between the first valve stem 3 and the second valve stem 14. The packing gland 7 is used to press the packing material 5. The packing gland 7 is fixed to the valve cover 4 by bolts. By pressing the packing material 5 with the packing gland 7, the first valve stem 3 and the second valve stem 14 are sealed to prevent high-pressure steam leakage during long-term use. Both the first valve stem 3 and the second valve stem 14 extend out of the valve cover 4. A sealing gasket is installed at the joint between the valve body 1 and the valve cover 4. The sealing gasket can be installed on the valve cover 4 or the valve body 1 and can seal the connection between the valve stem channel and the valve cover 4.

[0042] A valve stem nut 10 is provided on the upper side of the valve cover 4. A double-headed column 15 is fixed between the valve stem nut 10 and the valve cover 4. The diameters at both ends of the double-headed column 15 are smaller than the diameter in the middle part. The two ends of the double-headed column 15 are respectively inserted into the valve cover 4 and the valve stem nut 10. The two ends of the double-headed column 15 can be fixed to the valve cover 4 and the valve stem nut 10 by bolts. The larger diameter part in the middle of the double-headed column 15 is used to support the valve cover 4 and the valve stem nut 10 at both ends, so that the valve cover 4 and the valve stem nut 10 maintain a fixed distance. The valve stem nut 10 has a threaded hole, and a threaded valve stem 9 is rotatably provided in the threaded hole. The threaded valve stem 9 rotates in the threaded hole of the valve stem nut 10, and the outer surface of the threaded valve stem 9 has an external thread. Through the thread engagement of the external thread and the threaded hole, since the valve stem nut 10 is fixed, when the threaded valve stem 9 rotates, the threaded valve stem 9 will rise or fall depending on the direction of rotation of the threaded valve stem 9.

[0043] A handwheel 11 is fixedly mounted on the upper side of the threaded upper valve stem 9. The handwheel 11 and the threaded upper valve stem 9 are integrally fitted together. Rotating the handwheel 11 drives the threaded upper valve stem 9 to rotate. An anti-rotation block 8 is fitted together on the bottom of the threaded upper valve stem 9 and the outer top of the first valve stem 3 and the second valve stem 14. Stepped pins are provided on the bottom of the threaded upper valve stem 9 and the top of the first valve stem 3 and the second valve stem 14. The stepped pins at the bottom of the threaded upper valve stem 9 and the top of the first valve stem 3 and the second valve stem 14 abut against each other. The anti-rotation block 8 is fitted on the stepped pins at the bottom of the threaded upper valve stem 9 and the top of the first valve stem 3 and the second valve stem 14. The anti-rotation block 8 prevents the stepped pins from rotating. The engagement allows the bottom of the threaded valve stem 9 to move synchronously with the top of the first valve stem 3 and the second valve stem 14. That is, the up-and-down movement of the threaded valve stem 9 will synchronously drive the first valve stem 3 and the second valve stem 14 to move synchronously. The anti-rotation block 8 has grooves on both sides, and the grooves on both sides of the anti-rotation block 8 engage with the double-headed columns 15 located on both sides. This allows the anti-rotation block 8 to slide up and down within the double-headed columns 15 on both sides under the limitation of the double-headed columns 15 on both sides. The presence of the anti-rotation block 8 ensures that the rotation of the threaded valve stem 9 will not drive the first valve stem 3 and the second valve stem 14 to rotate. The first valve stem 3 and the second valve stem 14 will only follow the up-and-down movement of the threaded valve stem 9.

[0044] Flanges can be installed on both the sewage discharge pipe 18 and the final discharge pipe 17 for connection to external pipes. The sewage discharge valve of the above technical solution is applicable to media such as boiler steam sewage discharge with a diameter range of ≤100mm, a pressure range of ≤45MPa, and a temperature of ≤600°C.

[0045] The working principle of this structure is as follows: When the valve is in a non-working state, the shut-off valve 30 is in a closed state, that is, the first valve disc 2 blocks the interface between the sewage pipe 18 and the first valve stem channel 6, the shut-off check valve 40 is in a closed state, and the second valve disc 13 blocks the interface between the upper channel 19 and the lower channel 20 of the second valve stem channel 12.

[0046] When sewage discharge is required, manually rotate the handwheel 11 of the stop valve 30. The rotation of the handwheel 11 of the stop valve 30 drives the threaded valve stem 9 to rotate. The rotation of the threaded valve stem 9 cooperates with the valve stem nut 10, thereby causing the threaded valve stem 9 to rise. The threaded valve stem 9 drives the first valve stem 3 to rise through the anti-rotation block 8. The first valve stem 3 drives the first valve disc 2 to rise. The first valve disc 2 moves out from the interface between the sewage pipe 18 and the first valve stem channel 6. Steam flows out from the interface between the sewage pipe 18 and the first valve stem channel 6. When the first valve disc 2 is open, the steam medium is pressurized. The steam enters the flow channel pipe 16 through the sewage pipe 18. As the flow channel of the flow channel pipe 16 expands, the steam pressure decreases. The flow channel pipe 16 here plays a role in reducing the pressure of the steam medium in the pipe, preventing the steam from causing excessive erosion of the valve disc sealing surface and valve internals, and improving the service life of the valve. Because the steam has a certain pressure, the steam pressure pushes open the valve disc of the shut-off check valve 40. That is, since the second valve stem 14 is in sliding fit with the second valve stem 13, as long as the steam pressure is greater than the weight of the second valve disc 13, the second valve disc 13 can be pushed up from the interface between the upper channel 19 and the lower channel 20 of the second valve stem channel 12, so that the flow channel 16 is connected to the final discharge pipe 17, and the sewage in the boiler is discharged from the final sewage discharge pipe 18.

[0047] The second valve disc 13 opens automatically without manual intervention. The shut-off valve 30, a check valve, prevents the valve components from operating under high pressure at a small opening. An enlarged flow channel is designed in the middle of the flow channel 16, increasing the number of bends for the steam medium within the flow channel 16, thus providing better pressure reduction. This effectively reduces the scouring of the valve components by the medium and improves the valve's service life. When the shut-off valve 30 near the boiler fails to seal, i.e., when the first valve disc 2 fails to seal the interface between the drain pipe 18 and the first valve stem channel 6, the handwheel 11 corresponding to the second valve stem 14 can be turned to manually block the second valve disc 13 at the interface between the upper channel 19 and the lower channel 20 of the second valve stem channel 12, thereby closing the shut-off check valve 40. This also serves to close the valve, buying time for shutdown and maintenance.

[0048] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A high efficiency in-line boiler blowdown valve characterized by, The valve includes a valve body, which contains a first valve stem channel and a second valve stem channel. A flow channel connects the first valve stem channel and the second valve stem channel. A first valve disc is slidably disposed in the first valve stem channel, and a first valve stem is disposed in the first valve stem channel. The first valve stem is fixedly connected to the first valve stem. A second valve disc is slidably disposed in the second valve stem channel, and a second valve stem is disposed in the second valve stem channel. The second valve disc is slidably connected to the second valve stem. The second valve disc has an upward-opening groove, and the second valve stem is slidably disposed in the groove.

2. A high efficiency in-line boiler blowdown valve according to claim 1, wherein, The bottom of the first valve stem channel is connected to a sewage pipe. The first valve disc blocks the interface between the first valve stem channel and the sewage pipe. The interface between the first valve stem channel and the sewage pipe is lower than the interface between the first valve stem channel and the flow channel pipe.

3. A high efficiency in-line boiler blowdown valve according to claim 1, wherein, The second valve stem channel is a variable diameter pipe, which includes an upper pipe and a lower pipe. The inner diameter of the upper pipe is larger than the inner diameter of the lower pipe, and the flow channel is connected to the lower pipe.

4. A high efficiency in-line boiler blowdown valve according to claim 3, wherein, The second valve stem passage is connected to a final discharge pipe on its side, and the final discharge pipe is connected to the upper pipe. The second valve disc blocks the interface between the upper pipe and the lower pipe.

5. A high efficiency in-line boiler blowdown valve according to claim 2 wherein, The sewage pipe is a tapered pipe, and the inner diameter of the sewage pipe gradually decreases as it approaches the first valve stem channel.

6. The high-efficiency series boiler blowdown valve according to claim 1, characterized in that, The flow channel is a U-shaped pipe, and the inner diameter of the middle section of the flow channel increases outward.

7. A high efficiency in-line boiler blowdown valve according to claim 1 wherein, Both the first valve disc and the second valve disc have a conical structure.

8. A high efficiency in-line boiler blowdown valve according to claim 1 wherein, The valve body is provided with valve covers corresponding to the first valve stem and the second valve stem. The valve covers are provided with packing grooves. The first valve stem and the second valve stem pass through the packing grooves. Packing is provided between the packing grooves and the first valve stem and the second valve stem. A packing gland is pressed on the packing and is fixed on the valve covers.

9. A high efficiency in-line boiler blowdown valve according to claim 8 wherein, The valve cover is provided with a valve stem nut, and a double-headed column is fixed between the valve stem nut and the valve cover. A threaded upper valve stem is rotatably provided inside the valve stem nut. The threaded upper valve stem is threadedly engaged with the valve stem nut. A handwheel is fixedly provided on the threaded upper valve stem. Anti-rotation blocks are respectively provided between the threaded upper valve stem and the first valve stem and the second valve stem.

10. A high efficiency in-line boiler blowdown valve according to claim 8, wherein, A sealing gasket is provided on the valve cover or the valve body.

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