High temperature bellows pump

Abstract

The present application provides a high-temperature bellows pump, which solves the technical problem of existing bellows pumps in which the valve core is easily deformed during high-temperature expansion, causing a gap between the bellows and the valve core, resulting in liquid leakage and even the destruction of the pump body. The pump comprises a housing, a valve core disposed in the middle section of the housing, and two air cavities enclosed by the housing and the valve core, each of which is provided with a bellows and a push plate, with a connecting shaft connected between the two push plates. An annular boss is provided on the inner wall of the housing near the valve core, and the middle of the connecting shaft passes through the annular boss and the valve core, with a shaft sleeve provided between the connecting shaft and the annular boss. An expansion space is provided between at least the portion of the connecting shaft that cooperates with the valve core and the valve core, and an expansion guide assembly is provided between the valve core and the housing. The present application is widely used in the technical field of bellows pumps.

Description

Technical Field

[0001] The present application relates to a bellows pump, and more particularly to a bellows pump for high temperature use. Background Art

[0002] A bellows pump uses the expansion and contraction of a bellows to achieve liquid transport. Existing bellows pumps typically include a housing, a valve core, two bellows, and two push plates. A bellows is connected to each side of the valve core, and the other side of the bellows is connected to a push plate. The two push plates are connected by a connecting shaft that runs through the valve core. An air cavity is formed between the housing and the push plates, and the interior of the bellows connects to the piping within the valve core to form a liquid cavity. By alternately introducing compressed gas into the two air cavities of the housing, the push plates, driven by air pressure, drive the bellows to reciprocate and squeeze the liquid cavity within the tube, forcing liquid entering through the valve core's liquid inlet to be expelled from the valve core's liquid outlet, achieving the function of liquid transport through a continuous cycle.

[0003] A sleeve is installed between the connecting shaft and the valve core. To resist chemical corrosion, the valve core is typically made of high-temperature and corrosion-resistant materials such as polytetrafluoroethylene (PTFE), while the push plate and connecting shaft are typically made of stainless steel. Under high temperature conditions, the expansion rate of polytetrafluoroethylene is much greater than that of stainless steel. As the valve core expands due to heat, the sleeve shifts, and the combined push plate and connecting shaft expands minimally. The center of the connecting shaft no longer aligns with the center of the sleeve, causing radial extrusion between the two. This can easily cause surface deformation of the valve core, creating a gap between the bellows and the valve core, leading to liquid leakage and chemical corrosion of the pump body, ultimately rendering the bellows pump useless. Summary of the Invention

[0004] In order to solve the above problems, the technical solution adopted in this application is: to provide a high-temperature bellows pump, including a shell and a valve core arranged in the middle section of the shell, two air cavities surrounded by the shell and the valve core are provided with bellows and push plates, and a connecting shaft is connected between the two push plates; an annular boss is provided on the inner wall of the shell close to the valve core, the middle part of the connecting shaft passes through the annular boss and the valve core, and a shaft sleeve is provided between the connecting shaft and the annular boss; there is an expansion space between at least the part of the connecting shaft that cooperates with the valve core and the valve core; an expansion guide assembly is provided between the valve core and the shell.

[0005] Preferably, the expansion guide assembly includes a positioning member and a guide groove respectively provided on the valve core and the opposite end faces of the housing. The positioning member can extend into the guide groove and move radially under the guidance of the guide groove.

[0006] Preferably, the positioning members protrude from the end face of the valve core, and there are multiple of them, which are evenly distributed circumferentially with the center line of the valve core as the center; the guide grooves are recessed in the end face of the shell, and there are multiple of them, and the straight line where the center line of the guide groove is located passes through the center line of the valve core.

[0007] Preferably, the plurality of positioning members are distributed on one or more circles, and the centers of the one or more circles are all on the center line of the valve core.

[0008] Preferably, an adjusting shaft is also provided, which is movably arranged in an accommodating cavity formed in the valve core and the shell wall; the middle part of the adjusting shaft is located in the valve core, and the two ends are located in the shell wall; both ends of the adjusting shaft are sleeved with elastic parts in a compressed state, and the end of the elastic part close to the valve core is against the shell wall.

[0009] Preferably, there is expansion space between at least the portion of the regulating shaft that matches the valve core and the valve core.

[0010] Preferably, there are multiple adjusting shafts and accommodating cavities, and they are evenly distributed circumferentially inside the valve core and the housing wall.

[0011] Preferably, an elastic shock-absorbing bracket is provided in the gap of the elastic member, and the shock-absorbing bracket can shrink as the elastic member is compressed and expand as the spring is stretched.

[0012] Preferably, the valve core is made of polytetrafluoroethylene material, and the surface of the shell is covered with a polytetrafluoroethylene film or sprayed with a polytetrafluoroethylene coating.

[0013] The beneficial effect of the present invention is that the sleeve between the connecting shaft and the valve core is first moved to the housing with a lower temperature and expansion rate, and expansion space is created between at least the portion of the connecting shaft that matches the valve core and the valve core. Through reasonable design, the mutual influence of thermal expansion of the valve core, the connecting member, and the sleeve is avoided in a high-temperature environment, so that the center of the connecting shaft and the center of the sleeve always coincide with each other, so that there is no deformation of the valve core surface caused by extrusion, and no gap is generated between the bellows and the valve core to cause liquid leakage. Then, the thermal expansion deviation of the valve core in the three directions of X, Y, and Z is controlled: (1) an expansion guide assembly is provided between the valve core and the housing, and the expansion guide assembly includes a positioning member and a guide groove respectively provided on the opposite end faces of the valve core and the housing. The positioning member can extend into the guide groove and move radially under the guidance of the guide groove to control the radial (X, Y direction) thermal expansion deviation of the valve core, so that the center of the expanded valve core remains unchanged and always coincides with the action center of the bellows, avoiding the gap between the valve core and the bellows to cause liquid leakage. (2) An adjusting shaft is added between the valve core and the housing to control the thermal expansion deviation of the valve core in the axial direction (Z direction). When the valve core expands axially due to heat and contracts due to cooling, the elastic member in the compressed state can always exert pressure on the housing, forcing the housing and the valve core to always maintain a tight combination, avoiding the generation of gaps that may cause leakage or even the scrapping of the pump body. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0015] Figure 1 A schematic diagram of the main structure of the invented bellows pump;

[0016] Figure 2 for Figure 1 Schematic diagram of the left view structure;

[0017] Figure 3 for Figure 1 AA section view;

[0018] Figure 4 for Figure 1 BB cross-sectional view;

[0019] Figure 5 for Figure 1 CC cross-sectional view;

[0020] Figure 6 for Figure 2 DD cross-sectional view;

[0021] Figure 7 It is a schematic diagram of the connection between the connecting shaft and the push plate;

[0022] Figure 8 for Figure 6 Enlarged view of point A.

[0023] Explanation of symbols in the figure:

[0024] 1. Shell; 2. Valve core; 3. Bellows; 4. Push plate; 5. Connecting shaft; 6. Annular boss; 7. Bushing; 8. Positioning member; 9. Guide groove; 10. Adjusting shaft; 11. First expansion space; 12. Elastic member; 13. Accommodating chamber; 14. Stop platform; 15. Blocking structure; 16. Annular blocking part; 17. Threaded connection part; 18. Shock-absorbing bracket; 19. Second expansion space; 20. Cylindrical sleeve; 21. Shock-absorbing plate; 22. Left shell; 23. Right shell; 24. Shell cylinder; 25. End cover; 26. First sealing ring; 27. Second sealing ring; 28. Expansion guide assembly. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0026] It should be noted that, in the description of this application, “plurality” means two or more, unless otherwise clearly and specifically defined.

[0027] The high-temperature bellows pump provided in the embodiments of the present application is now described.

[0028] See also Figure 1 、 Figure 3 , is a structural schematic diagram of the bellows pump of this embodiment. The high-temperature bellows pump includes a housing 1, a valve core 2 provided in the middle section of the housing 1, a bellows 3 and a push plate 4 are provided in the two air cavities enclosed by the housing 1 and the valve core 2, and a connecting shaft 5 is connected between the two push plates 4; an annular boss 6 is provided on the inner wall of the housing 1 near the valve core 2, the middle portion of the connecting shaft 5 passes through the annular boss 6 and the valve core 2, and a shaft sleeve 7 is provided between the connecting shaft 5 and the annular boss 6; a first expansion space 11 is provided between the valve core 2 and at least the portion of the connecting shaft 5 that cooperates with the valve core 2.

[0029] In order to form a first expansion space 11 to allow for the thermal expansion of the valve core 2, the valve core 2 and / or the connecting shaft 5 can be processed, preferably by necking the connecting shaft 5 so that the expansion of the valve core 2 and the connecting shaft 5 do not affect each other. In addition, the sleeve 7 is moved to the housing 1, which has a similar or identical expansion rate to the connecting shaft 5, which can minimize the probability of deformation of the connecting shaft 5 due to its own expansion or the expansion of other components. In addition, the sleeve 7 is made of oil-free, low-friction modified tetrafluoroethylene resin, which has excellent wear resistance. The disadvantage is that the material has a low hardness and will also expand when heated. The temperature of the housing 1 is much lower than that of the valve core 2, so the amount of expansion of the sleeve 7 transferred to the housing 1 will be greatly reduced, and will not have an adverse effect on the performance of the bellows pump.

[0030] To further illustrate, the gas injected into the air cavity is cold, dry compressed air. When the bellows 3 switches from being stationary to moving, the pressure of the injected gas is constant. The amount of gas injected increases as the bellows 3 contracts. The temperature of the cold, dry compressed air is also much lower than the temperature of the bellows 3 and other components inside the bellows pump. As the gas is continuously injected and discharged, the gas continuously absorbs heat from the surrounding high-temperature environment, thereby achieving the purpose of cooling the housing 1. In a high-temperature environment, the temperature of the working bellows pump housing 1 is only 50-55°C, and the maximum temperature of the standby bellows pump housing 1 does not exceed 60°C (measured at room temperature of 23°C ± 2°C). When the shaft sleeve 7 is set on the housing 1, the influence of thermal expansion can be effectively avoided. In a 60°C environment, the expansion of the shaft sleeve 7 is about 0.1-0.15mm. This change will not have an adverse effect on the performance of the bellows pump.

[0031] In order to prevent the external environment from corroding the connecting shaft 5, the connecting shaft 5 needs to be isolated from the outside world to achieve the purpose of preventing corrosion. A first sealing ring 26 is provided between the valve core 2 and the housing 1 outside the connecting shaft 5.

[0032] When high-temperature liquid continuously flows in the bellows pump, the temperature of the valve core 2 will gradually rise from the pipe wall inside the valve core 2, and the valve core 2 will gradually expand due to the heat. The valve core 2 is made of polytetrafluoroethylene material and has a flat cylindrical structure. In order to prevent the valve core 2 from deforming due to heat and causing the center of the valve core 2 to shift, in one embodiment, please refer to Figure 4 ,for Figure 1 A schematic cross-sectional view of a bellows pump taken along line BB. An expansion guide assembly 28 is provided between the valve core 2 and the housing 1. This assembly includes a positioning member 8 and a guide groove 9, which are provided on opposing end surfaces of the valve core 2 and the housing 1, respectively. The positioning member 8 can extend into the guide groove 9 and move radially under its guidance.

[0033] Furthermore, multiple positioning members 8 protrude from both end surfaces of the valve core 2 and are evenly distributed circumferentially around the centerline of the valve core 2. Correspondingly, multiple guide grooves 9 are recessed into the housing 1 on both end surfaces opposite the valve core 2, with the centerlines of the guide grooves 9 traversing the centerline of the valve core 2. As the valve core 2 expands due to heat, the positioning members 8 can move in a directional manner within the constraints of the guide grooves 9, ensuring that the center of the valve core 2 remains unchanged.

[0034] Furthermore, considering the interference of other factors such as gravity, the multiple positioning members 8 are distributed on one or more circles, and the centers of the one or more circles are all on the center line of the valve core 2.

[0035] Specifically, this embodiment includes six positioning members 8 and six guide slots 9, each with a length greater than or equal to the expansion capacity. Positioning members 8 are arranged on the valve core 2 based on the expansion capacity under specific conditions. Positioning members 8 in the upper semicircle have a radius of R1, while those in the lower semicircle have a radius of R2. The radii R1 and R2 differ because the lower portion of the valve core 2 is affected by gravity or other conditions, resulting in different stretching capacities.

[0036] When the valve core 2 undergoes thermal expansion, the positioning member 8 is restrained by the two straight edges of the guide groove 9 and moves along the centerline of the guide groove 9 in a direction away from the center of the valve core 2. Therefore, with the cooperation of the positioning member 8 and the guide groove 9, the radial (X and Y directions) thermal expansion deviation of the valve core 2 is controlled. Even if the valve core 2 is not a perfect circle after expansion, its center can still be ensured to remain unchanged. In other words, it can still coincide with the operating center of the bellows 3, thereby preventing the formation of a gap between the valve core 2 and the bellows 3, which could cause liquid leakage.

[0037] To reduce friction during valve core 2's movement, the valve core 2 is made of polytetrafluoroethylene (PTFE), and the housing 1 is coated with a polytetrafluoroethylene film or sprayed with a PTFE coating, resulting in a friction coefficient of only approximately 0.03. Therefore, when thermal expansion occurs, the valve core 2 can move slowly on the surface of the housing 1, virtually unaffected by friction.

[0038] The bellows pump has the following working conditions: (1) It is installed inside other equipment and operates at high temperature for a long time, continuously transporting liquid; (2) The installed equipment stops for a short time due to various reasons, but the bellows pump stops working but continues to be heated; (3) The installed equipment does not operate for a long time, the bellows pump will stop working for a long time, and the internal temperature will gradually drop to room temperature. The above three working conditions do not exist independently, and various working conditions are constantly cyclical. Therefore, the bellows pump needs to continuously switch between working conditions such as continuous high-temperature operation, continuous high-temperature stop, and continuous normal temperature placement. When the various working conditions are switched, the valve core 2 continuously expands and contracts. The fixed distance connection between the valve core 2 and the housing 1 can no longer meet the requirements of the changing working conditions, causing the connection between the valve core 2 and the housing 1 to be easily permanently deformed and leaked. Therefore, it is not enough to only control the radial (X, Y direction) thermal expansion offset of the valve core 2.

[0039] See also Figure 1 、 Figure 2 、 Figures 4 to 6 In one embodiment, the axial (Z direction) thermal expansion offset is controlled. Specifically, an adjusting shaft 10 is added between the valve core 2 and the housing 1. The adjusting shaft 10 is movably arranged in an accommodating cavity 13 formed in the valve core 2 and the wall of the housing 1; the middle part of the adjusting shaft 10 is located in the valve core 2, and the two ends are located in the wall of the housing 1; there is a second expansion space 19 between the portion of the adjusting shaft 10 that cooperates with the valve core 2 and the valve core 2. The formation of the second expansion space 19 can refer to the first expansion space 11 and will not be repeated here. Both ends of the adjusting shaft 10 are sleeved with elastic parts 12 in a compressed state. The end of the elastic part 12 away from the valve core 2 is connected to the adjusting shaft 10, and the end of the elastic part 12 close to the valve core 2 abuts against a baffle 14 in the accommodating cavity 13. The baffle 14 is located in the wall of the housing 1. The connection between the elastic part 12 and the adjusting shaft 10 can be a fixed connection or a movably sleeved connection. A blocking structure 15 is provided at the end of the adjusting shaft 10. Please refer to Figure 8The blocking structure 15 can be a combination of an annular blocking portion 16 and a threaded connection portion 17. The annular blocking portion 16 presses against the distal end of the elastic member 12, and the threaded connection portion 17 is threadedly connected and fixed to the adjusting shaft 10. The elastic member 12 can be any component that can provide axial elastic restoring force. When the valve core 2 expands axially due to heat, it pushes the shells 1 on both sides to move toward the distal end (away from the valve core 2). The shell 1 applies pressure to the elastic members 12 at both ends of the adjusting shaft 10 through the stop 14, and the elastic member 12 is compressed. At this time, the elastic member 12 can also give a reaction force to the shell 1, so that the shell 1 and the valve core 2 are tightly combined. When the valve core 2 cools and retracts axially, the restoring force of the elastic member 12 forces the shell 1 to move toward the proximal end (close to the valve core 2) as the valve core 2 retracts, and also keeps the valve core 2 and the shell 1 tightly combined to avoid gaps and leakage.

[0040] In one embodiment, to ensure that the end surfaces of the valve core 2 and the housing 1 are tightly fitted with each other without any gap, multiple adjusting shafts 10 and accommodating cavities 13 can be provided and evenly distributed in the circumferential direction within the walls of the valve core 2 and the housing 1. Figure 4 and Figure 5 Four adjusting shafts 10 are provided, two at the top and two at the bottom; two connecting shafts 5 are provided, positioned opposite each other in the middle. The adjusting shafts 10, connecting shafts 5, and expansion guide assembly 28 are interlaced. The accommodating chamber 13 is formed by a transverse through-hole within the valve core 2 and corresponding slots on the walls of the housing 1 on either side of the valve core 2. The through-hole and the two slots combine to form the accommodating chamber 13. The stop 14 is located on the inner wall of the accommodating chamber 13 within the housing 1 and can be an annular structure or a separate block-shaped structure.

[0041] Furthermore, when a bellows pump is in operation, it often experiences internal impacts. When the frequency of the impact force on the elastic member 12 approaches its natural frequency, it can generate significant noise. In one embodiment, a resilient, shock-absorbing bracket 18 is provided between the elastic members 12. The bracket 18 typically comprises a cylindrical sleeve 20 and a shock-absorbing sheet 21, shaped to match the elastic member 12, positioned outside the cylindrical sleeve 20. The cylindrical sleeve 20 is sleeved onto the adjustment shaft 10, and the shock-absorbing sheet 21 is inserted between the various parts of the elastic member 12, preventing the elastic members 12 from colliding and making noise when vibrating.

[0042] See also Figure 8 The elastic member 12 is preferably a spring. The damping plate 21 of the damping bracket 18 is a spiral damping plate that matches the shape of the spring. The spring is distributed between the spiral damping plates. When the spring is compressed, the spiral damping plates are also pressed tightly against the spring, preventing the spring from vibrating and emitting noise. During assembly, the cylindrical sleeve 20 is first placed on the adjustment shaft 10 in the direction of the spring's rotation, and the spring is then wound and distributed between the spiral damping plates.

[0043] To facilitate assembly, the housing 1 includes a left housing 22 and a right housing 23 that are arranged relative to each other. The left housing 22 and the right housing 23 both include a shell barrel 24 provided with an annular boss 6 and an end cover 25. The shell barrel 24 is provided with one end of a guide groove 9 that is connected to the valve core 2, and the other end of the shell barrel 24 is connected to the end cover 25. Specifically, the connection can be a fixed connection or a detachable connection. The detachable connection can be made by a bolt or other connection method. Furthermore, the inner diameter of the annular boss 6 matches the outer diameter of the bellows 3. A second sealing ring 27 is provided between the shell barrel 24 and the end cover 25. The shape of the second sealing ring 27 matches the shape of the push plate 4 and is located on the outside of the push plate 4 to seal the air cavity.

[0044] Regarding the location of the sleeve 7, a mounting hole is provided on the end surface of the shell 24 opposite to the end cover 25. The sleeve 7 is arranged in the mounting hole at one end close to the end cover 25. This position is the rigid body closest to the bellows 3, the connecting shaft 5 and the push plate 4 (see Figure 7 ) The mass center during operation is as close to the stress point as possible, reducing the bending stress of the connecting shaft 5.

[0045] The present invention first moves the sleeve 7 between the connecting shaft 5 and the valve core 2 to the housing 1 with a lower temperature and expansion rate, and allows expansion space to exist between at least the part of the connecting shaft 5 that cooperates with the valve core 2 and the valve core 2. Through reasonable design, the mutual influence of thermal expansion of the valve core 2 and the connecting parts and the sleeve 7 under high temperature environment is avoided, so that the center of the connecting shaft 5 and the center of the sleeve 7 always remain coincident, so that there is no situation where the surface of the valve core 2 is deformed by extrusion, and there is no gap between the bellows 3 and the valve core 2 to cause liquid leakage. The thermal expansion deviation of the valve core 2 in the X, Y, and Z directions is then controlled: (1) an expansion guide assembly 28 is provided between the valve core 2 and the housing 1. The expansion guide assembly 28 includes a positioning member 8 and a guide groove 9 provided on the opposite end faces of the valve core 2 and the housing 1, respectively. The positioning member 8 can be inserted into the guide groove 9 and move radially under the guidance of the guide groove 9 to control the radial (X, Y directions) thermal expansion deviation of the valve core 2, so that the center of the valve core 2 after expansion remains unchanged and always coincides with the action center of the bellows 3, thereby avoiding the formation of a gap between the valve core 2 and the bellows 3 and causing liquid leakage. (2) an adjusting shaft 10 is added between the valve core 2 and the housing 1 to control the axial (Z direction) thermal expansion deviation of the valve core 2. When the valve core 2 expands axially due to heat and contracts due to cooling, the elastic member 12 in a compressed state can always apply pressure to the housing 1, forcing the housing 1 and the valve core 2 to always remain tightly combined, thereby avoiding the formation of a gap that causes leakage or even the scrapping of the pump body.

[0046] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A high-temperature bellows pump comprising a housing, a valve core disposed in the middle of the housing, two air cavities enclosed by the housing and the valve core, both of which are provided with a bellows and a push plate, with a connecting shaft connecting the two push plates; characterized in that: An annular boss is provided on the inner wall of the housing near the valve core, the middle portion of the connecting shaft passes through the annular boss and the valve core, and a shaft sleeve is provided between the connecting shaft and the annular boss; an expansion space is provided between at least the portion of the connecting shaft that cooperates with the valve core and the valve core; an expansion guide assembly is provided between the valve core and the housing; An adjusting shaft is also provided, the adjusting shaft being movably disposed in an accommodating cavity formed in the valve core and the housing wall; the middle portion of the adjusting shaft is located in the valve core, and both ends are located in the housing wall; both ends of the adjusting shaft are sleeved with elastic members in a compressed state, and the end of the elastic member closest to the valve core abuts against the housing wall; There is an expansion space between at least the portion of the regulating shaft that cooperates with the valve core and the valve core; The valve core is made of polytetrafluoroethylene material, and the surface of the shell is covered with a polytetrafluoroethylene film or sprayed with a polytetrafluoroethylene coating.

2. The high-temperature bellows pump according to claim 1, wherein: The expansion guide assembly includes a positioning member and a guide groove respectively provided on the valve core and the opposite end faces of the housing. The positioning member can extend into the guide groove and move radially under the guidance of the guide groove.

3. The high-temperature bellows pump according to claim 2, wherein: The positioning members protrude from the end face of the valve core, and there are multiple of them, and they are evenly distributed circumferentially with the center line of the valve core as the center; the guide grooves are recessed in the end face of the shell, and there are multiple of them, and the straight line where the center line of the guide groove is located passes through the center line of the valve core.

4. The high-temperature bellows pump according to claim 3, wherein: The plurality of positioning members are distributed on one or more circles, and the centers of the one or more circles are all on the center line of the valve core.

5. The high-temperature bellows pump according to claim 1, wherein: There are multiple regulating shafts and accommodating cavities, which are evenly distributed in the valve core and the shell wall in the circumferential direction.

6. The high-temperature bellows pump according to claim 1, wherein: An elastic shock-absorbing bracket is provided in the gap of the elastic member. The shock-absorbing bracket can shrink as the elastic member is compressed and expand as the spring is stretched.

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