A circulating pump with internal circulation cooling and lubrication function

Abstract

This invention belongs to the field of circulating pump technology, specifically relating to a circulating pump with internal circulation cooling and lubrication functions. The invention includes a pump casing and a pump shaft arranged within the inner cavity of the pump casing. The inner cavity of the pump casing is divided by a seal into a working medium area at the front for accommodating the impeller and a lubrication and cooling area at the rear. The invention is characterized by the following components arranged sequentially from front to back on the pump shaft within the lubrication and cooling area: a front radial bearing, a front sealing ring, an isolation sleeve, a rear radial bearing, a rear sealing ring, a drive disc, a rear flange, and a bottom flange. The bottom flange is assembled at the rear end of the pump casing to seal the inner cavity of the pump casing. A heat exchanger is installed on the outer end face of the bottom flange. This invention eliminates the need for an external pressure source, utilizing the circulating pump's own power to simultaneously achieve internal circulation cooling and lubrication functions, offering advantages such as compact structure and reliable and convenient operation.

Description

Technical Field

[0001] This invention belongs to the field of circulating pump technology, specifically relating to a circulating pump with internal circulation cooling and lubrication functions. Background Technology

[0002] With the significant surge in energy consumption, the substantial energy gap will primarily be filled by unconventional resource technologies such as heavy oil and coal direct liquefaction processes. Emerging technologies like circulating bed and suspended bed systems play a particularly prominent role in heavy oil and coal direct liquefaction processes, with the circulating pump being one of the core components. Depending on the device characteristics and working medium requirements, in actual assembly, the circulating pump must be suspended outside the reactor, operating as a single pump without a backup. The energy provided by the circulating pump controls the backmixing of materials within the reactor and the expansion of the catalyst bed. However, due to the unique operating mode of the circulating pump, significant heat is generated inside, especially in the motor area. Over prolonged operation, this heat accumulates and is difficult to dissipate, easily damaging the motor and the oil wedge, leading to dry friction and bearing damage. Therefore, a continuous supply of lubricating oil is necessary to dissipate the generated heat and establish a new oil wedge to achieve dynamic equilibrium. Furthermore, current practical applications typically involve adding an additional pump to deliver lubricating oil to the circulating pump. This method is not only space-consuming and structurally complex, but also expensive and increases maintenance costs. Furthermore, considering the stringent requirements of the high pressure of the working medium within the pump body on the internal seals, labyrinth seals are typically added on the back of the impeller to isolate the working medium area where the impeller is located from the lubrication and cooling area where the lubricant is located. During operation, the external pump applies pressure to the lubricant, allowing it to slowly seep into the working medium area through the labyrinth seal and be discharged from the pump body along with the working medium. However, when the pump malfunctions, the enormous pressure of the working medium in the working medium area can push against the labyrinth seal and seep into the lubrication and cooling area through it, causing pressure loss and material discharge. In particular, the working medium often contains a large number of solid particles. Once these solid particles enter the lubrication and cooling area, they will inevitably damage the relatively fragile bearings, motors, and oil circuits, subsequently causing unplanned shutdowns of the circulating pump, ultimately resulting in significant losses of manpower, material resources, and financial resources, which urgently needs to be addressed. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a circulating pump with internal circulation cooling and lubrication function. It can realize the internal circulation cooling and internal circulation lubrication functions of the circulating pump simultaneously by utilizing the circulating pump's own power without the need for an external pressure source. It has the advantages of compact structure and reliable and convenient use.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A circulating pump with internal circulation cooling and lubrication function includes a pump casing and a pump shaft arranged in the inner cavity of the pump casing. The inner cavity of the pump casing is divided by a seal into a working medium area at the front for accommodating the impeller and a lubrication and cooling area at the rear. The pump shaft in the lubrication and cooling area is characterized by the following components arranged sequentially from front to back: a front radial bearing, a front sealing ring, an isolation sleeve, a rear radial bearing, a rear sealing ring, a drive disc, a rear flange, and a bottom flange. The bottom flange is assembled at the rear end of the pump casing to seal the inner cavity of the pump casing. The front radial bearing and the front sealing ring are combined to form a front sealing seat for sealing the front end face of the isolation sleeve; the rear radial bearing and the rear sealing ring are combined to form a rear sealing seat for sealing the rear end face of the isolation sleeve; the front sealing seat, the rear sealing seat and the isolation sleeve together enclose a sealed mounting cavity for accommodating the motor; the rear sealing ring and the rear flange are fixed to each other and enclose a receiving cavity for accommodating the drive disc. A heat exchanger is installed on the outer end face of the bottom flange. The coolant outlet of the heat exchanger passes through the bottom flange and connects to the inlet hole located in the pump shaft. The coolant passes through the radially arranged outlet hole at the pump shaft and is thrown into the radial hole in the drive disc under the centrifugal force of the drive disc and enters the receiving cavity. Then, it passes through the connecting hole arranged at the rear sealing ring and / or the movable clearance of the rear radial bearing and enters the mounting cavity. Then, it enters the cavity wall flow channel reserved between the isolation sleeve and the inner cavity wall of the pump casing along the movable clearance of the front radial bearing. Then, it flows back to the bottom flange through the cavity wall flow channel and then flows back to the coolant inlet of the heat exchanger through the pre-set through hole at the bottom flange.

[0005] Preferably, the drive disk is disc-shaped, and slots are arranged at the cavity walls at both ends of the drive disk. Limiting plates are installed in the slots, and limiting grooves are installed on the limiting plates. Friction plates are located in the limiting grooves. The friction plates and the drive disk form a thrust bearing structure.

[0006] Preferably, an annular groove is arranged at the bottom of the slot and an adjusting ring is placed inside the annular groove. The threaded section of the adjusting screw, which rotates and fits on the adjusting ring, fits at the bottom of the annular groove. The limiting piece is annular in shape, and a positioning protrusion is provided at one end of the limiting piece facing the slot. The positioning protrusion abuts against the corresponding annular surface of the adjusting ring.

[0007] Preferably, the heat exchanger includes a heat dissipation coil, and the heat dissipation coil is covered with a barrel-shaped outer cover. The barrel opening of the outer cover is coaxially fitted at the outer end face of the bottom flange. The area between the outer cover and the heat dissipation coil constitutes a heat exchange area. A liquid inlet and a liquid outlet communicating with the heat exchange area are arranged on the outer cover.

[0008] Preferably, both the front radial bearing and the rear radial bearing are sliding bearings; a drive source for driving the motor is arranged on the outer wall of the pump casing.

[0009] Preferably, the sealing element is a baffle sealing assembly; the baffle sealing assembly includes a throttling sleeve and a baffle sleeve coaxially sleeved on the pump shaft and arranged sequentially from front to back along the pump shaft axial direction. The throttling sleeve is fixed to the pump housing so that it can rotate coaxially relative to the baffle sleeve; the baffle sleeve is located in front of the front radial bearing, and the cylindrical cavity of the baffle sleeve has a two-stage stepped hole shape. The small-diameter section of the baffle sleeve forms a fixed cavity for fixing the pump shaft, and the large-diameter section of the baffle sleeve extends axially and fits on the outer wall of the throttling sleeve, so that the lubricating fluid can sequentially travel through the radial gap between the inner wall of the large-diameter section and the outer wall of the baffle sleeve, the axial space between the end of the throttling sleeve and the shoulder of the baffle sleeve hole, and the radial gap between the inner wall of the throttling sleeve and the outer wall of the pump shaft, and then enter the working medium area; the axial space between the end of the throttling sleeve and the shoulder of the baffle sleeve hole forms a baffle storage area for temporarily storing solid particles.

[0010] Preferably, the throttling sleeve includes a main sleeve as the main body and an extension sleeve extending axially from the end of the main sleeve. The main sleeve is threadedly fixed to the pump housing, and the extension sleeve extends into the large-diameter section to cooperate with the baffle sleeve to form the baffle storage area. The radial gap between the extension sleeve and the pump shaft is larger than the radial gap between the main sleeve and the pump shaft.

[0011] Preferably, a labyrinth seal is also arranged on a section of the pump shaft between the throttling sleeve and the working medium area. The labyrinth seal and the pump casing form a stop fit that restricts the labyrinth seal from moving unidirectionally towards the working medium area. The cylindrical cavity of the labyrinth seal is fitted to the outer wall of the pump shaft, and there is a gap between the tail end of the labyrinth seal and the corresponding end of the throttling sleeve.

[0012] Preferably, an impeller is coaxially mounted on the pump shaft in the working medium zone; an annular pre-grinding section is coaxially protruding on the back of the impeller, the pre-grinding section being a thrust bearing; the stop of the pre-grinding section is fitted at the shoulder of the pump shaft, and there is a gap between the first end of the labyrinth seal and the shoulder that allows lubricating fluid to pass through; the diameter of the pre-grinding section is smaller than the diameter of the first end face of the labyrinth seal.

[0013] Preferably, the radial gaps between the inner wall of the large-diameter section and the outer wall of the baffle sleeve, and between the inner wall of the throttling sleeve and the outer wall of the pump shaft, are both 0.5 mm, and the length-to-diameter ratio at the corresponding radial gaps is 1.2 to 1.5 times the length of the radial gaps; and the calculation steps for the axial length h of the baffle storage area at the baffle sealing assembly are as follows: S1. Calculate the volume of solid particles settling per minute when solid particles enter the baffled storage area using the following formula. :

[0014] in: V is the settling velocity of the solid particles, in m / s; S represents the cross-sectional area of ​​the baffled storage region, in units of... ; S2. Calculate the volume of the folded storage area using the following formula. :

[0015] in: T is the time from when the lubricating fluid loses pressure until solid particles enter the lubrication and cooling zone, in minutes; S3. Calculate the axial length h of the baffled storage area using the following formula:

[0016] in: R1 is the radius of the mating point of the pump shaft, in meters; R2 is the radius of the large aperture section, in meters.

[0017] The beneficial effects of this invention are as follows: 1) Through the above scheme, in actual operation, the present invention can drive the drive disc to rotate with the rotation of the pump shaft, thereby driving the entire oil circuit to circulate inside the pump casing; the actual oil circuit starts from the heat exchanger, sequentially passes through the receiving cavity to the lower radial bearing, motor, and upper radial bearing, and then returns from the installation cavity to the cavity wall flow channel formed by the isolation sleeve and the pump casing to the heat exchanger fixed at the bottom flange, thereby achieving the purpose of continuous internal circulation lubrication and cooling without stopping the pump shaft.

[0018] Thus, this invention can achieve effective oil circulation by relying solely on the internal oil circuit of the pump casing without additional structural or protective measures, even when external conditions are insufficient or lubrication and cooling cannot be met. This simultaneously satisfies the internal circulation cooling and lubrication requirements of the circulating pump, and has the advantages of compact structure and reliable and convenient use, ultimately greatly extending the actual service life of the circulating pump.

[0019] 2) Furthermore, since the drive disc, as the power component driving the entire oil circuit to generate propulsion, has its axis in a vertical state during operation, this invention adds a limiting plate with friction plates, thereby forming a thrust bearing structure between the friction plates and the drive disc. Under the pressing action of the friction plates, the vibration generated by the circulating pump during operation can prevent the increase of the clearance at the aforementioned thrust bearing structure, effectively reduce the axial displacement of the pump shaft, eliminate safety hazards, and enhance the stability of the circulating pump operation.

[0020] 3) During actual installation of the limiting plate, the design of the annular groove and adjusting screw in this invention allows the adjusting ring to move axially when the adjusting screw is turned. This, in turn, pushes the limiting plate to move up and down, thus achieving controllable adjustment of the thrust of the drive disc. This simple and quick adjustment method can speed up the maintenance process and improve the working efficiency of the circulating pump.

[0021] 4) By employing a baffle sealing assembly, during normal operation, the lubricant first passes through the radial gap between the baffle sleeve and the throttling sleeve, then folds back through the baffle storage area and enters the inner cavity of the throttling sleeve, achieving initial throttling. Finally, a portion of the lubricant flowing out of the mounting cavity enters the working medium area through the back of the impeller. When the lubrication and cooling area loses pressure due to a malfunction, the long gaps formed between the throttling sleeve and the pump shaft, as well as between the throttling sleeve and the baffle sleeve, effectively slow down the backflow velocity of the working medium, extending the time for the working medium to enter the lubrication and cooling area from the working medium area. Simultaneously, after passing through the long gap between the throttling sleeve and the pump shaft, the working medium first enters the baffle storage area and folds back. This further decelerates the working medium and causes solid particles entrained in the working medium to settle and accumulate in the baffle storage area due to stalling. The long gap formed between the throttling sleeve and the deflector sleeve acts as the last barrier, further preventing the diffusion of solid particles into the lubrication and cooling zone. Ultimately, this achieves the protection function for the power components and even the entire circulating pump within the lubrication and cooling zone, greatly improving the working safety of the circulating pump, reducing unnecessary maintenance and repair costs, and facilitating practical use.

[0022] 5) The labyrinth seal, based on the initial throttling achieved by the aforementioned throttling sleeve and baffle sleeve, achieves a secondary throttling effect. During normal operation, the labyrinth seal serves as a secondary throttling element after the initial throttling; however, when the working medium backflows due to pressure loss in the lubrication and cooling zone, the labyrinth seal can provide reverse pressure, delaying leakage time. Thus, in conjunction with the throttling sleeve and baffle sleeve, it achieves a better effect of extending the penetration of the working medium into the lubrication and cooling zone.

[0023] 6) In actual operation, the pump shaft of the circulating pump is entirely supported by a thrust bearing structure. This means the pump shaft is significantly affected by the working condition of the thrust bearing structure. In other words, when the axial thickness of the thrust bearing structure thins due to usage time, the entire pump shaft will sink, causing the back of the impeller fixed to the pump shaft to directly contact the hard pump casing. The high-speed rotating impeller violently scrapes against the pump casing, easily causing wear and even cracking. This invention addresses this by protruding a small annular surface on the back of the impeller, i.e., a pre-grinding section, with a diameter smaller than that of the labyrinth seal. This ensures that even if the pump shaft sinks, causing the impeller to sink, the impeller will not rub against the pump casing; instead, it will only rub against the labyrinth seal through the pre-grinding section. Replacing the labyrinth seal is obviously much cheaper and more convenient than replacing the entire pump body and impeller, making subsequent maintenance extremely convenient and cost-effective.

[0024] 7) Of course, the pre-grinding section is preferably formed naturally using a thrust bearing; this allows the pump shaft to sink, changing the originally intense sliding fit between the pump shaft and the labyrinth seal to relatively gentle rolling friction. At the same time, due to the rolling clearance of the thrust bearing, the back of the impeller will not block the lubricant from seeping into the working medium area, thus ensuring normal communication between the lubrication and cooling area and the working medium area, ultimately ensuring the continuous and safe operation of the circulating pump.

[0025] 8) Based on the above structure, this invention also provides an axial length calculation method for the baffle sealing assembly. This method ensures that the equipment is safe for at least the specified time during which an oil injection failure occurs, that is, considering the pressure balance time and the total time for baffle sedimentation, etc. Even after the failure is resolved, the equipment can be used directly without disassembly and inspection. Only the baffle storage area at the lower throttling sleeve and the baffle sleeve needs to be maintained. This greatly improves the overall safety and significantly reduces unnecessary waste of manpower and resources, resulting in significant benefits. Attached Figure Description

[0026] Figure 1 This is an assembly diagram of the present invention; Figure 2 for Figure 1 A magnified view of part I; Figure 3 for Figure 1 A magnified view of part II.

[0027] The actual correspondence between the reference numerals and component names in this invention is as follows: a-Working medium area b-Lubrication and cooling area b1 - Receiving cavity; b2 - Mounting cavity; b3 - Cavity wall flow channel; c - Baffle storage area 10-Pump casing; 11-Bottom flange; 11a-Through hole 20-Pump shaft 21-Discharge hole 30-Impeller 31-Pre-grinding section 41-Front radial bearing; 42-Front sealing ring; 43-Isolation sleeve 44 - Rear radial bearing; 45 - Rear sealing ring; 45a - Connecting hole 46-Drive plate 46a-Radial hole 47-Rear flange 48-Motor 50-Heat exchanger; 61-Limiting plate; 62-Friction plate; 63-Adjusting ring; 64-Adjusting screw 70-Drive source; 81-Throttle sleeve; 81a-Main sleeve; 81b-Extension sleeve 82-Baffle Sleeve 83-Maze Seal Detailed Implementation

[0028] For ease of understanding, this section combines... Figure 1-3 The specific structure and operation of the present invention are further described below: The overall structure of the present invention is as follows Figure 1 As shown, the system includes a pump housing 10 and a pump shaft 20 located within the pump housing 10. The bottom end of the pump shaft 20 is rotatably fitted onto a thrust bearing structure. Therefore, when the pump shaft 20 is in a vertical working state, the axial force of the thrust bearing structure ensures the normal working position of the pump shaft 20. Simultaneously, the radial force of the pump shaft 20 is achieved through two sets of sliding bearings: a front radial bearing 41 and a rear radial bearing 44. Both sets of sliding bearings are located at both ends of an isolation sleeve 43, and the inner cavity of the isolation sleeve 43 forms a mounting cavity for housing the motor 48. In actual installation, the rotor of the motor 48 is coaxially mounted on the pump shaft 20, while the stator is fixed to the isolation sleeve 43. The motor 48 receives external power from a drive source 70 located outside the pump housing 10. Wherein: When the isolation sleeve 43 is coaxially inserted into and fixed inside the pump housing 10 along the opening at the tail end of the pump housing 10, there is a gap between the outer wall of the isolation sleeve 43 and the inner wall of the pump housing 10. Figure 3 The cavity wall flow channel b3 shown constitutes a return channel for lubricating oil. Figure 3 As shown, the rear mounting seat is formed by the rear sealing ring 45 and the rear flange 47 being fixedly connected to each other, and the space enclosed between them forms a receiving cavity b1 for accommodating the drive disc 46. Similarly, the front radial bearing 41 and the front sealing ring 42 are combined to form a front sealing seat for sealing the front end face of the isolation sleeve 43; the rear radial bearing 44 and the rear sealing ring 45 are combined to form a rear sealing seat for sealing the rear end face of the isolation sleeve 43; the front sealing seat, the rear sealing seat, and the isolation sleeve 43 together enclose a sealed mounting cavity b2 for accommodating the motor 48.

[0029] During internal circulation of lubricating oil, it is not only necessary to achieve its simple lubrication function, but also to utilize its heat-carrying properties after circulation to ensure the cooling of the motor 48 and other heat-generating components. Therefore, in this invention, after the bottom flange 11 is used to seal the tail end opening of the pump casing 10, a heat exchanger 50 is fitted at the outer end face of the bottom flange 11. The heat exchanger 50 includes an outer casing and a heat dissipation coil. The outer casing flange fits onto the bottom flange 11. The coolant outlet of the heat dissipation coil passes through the bottom flange 11 and connects to the inlet hole located inside the pump shaft 20. The coolant passes through the radially arranged outlet hole 21 at the pump shaft 20 and is thrown into the radial hole 46a inside the drive disc 46 under the centrifugal force of the drive disc 46 and enters the receiving cavity b1. Then, it passes through the connecting hole 45a arranged at the rear sealing ring 45 and / or the movable clearance of the rear radial bearing 44 and enters the mounting cavity b2. Then, it passes through the gap between the rotor and stator of the motor 48 and then enters the cavity wall flow channel b3 reserved between the isolation sleeve 43 and the inner cavity wall of the pump housing 10 along the movable clearance of the front radial bearing 41. Then, it flows back to the bottom flange 11 through the cavity wall flow channel b3 and then flows back to the coolant inlet of the heat dissipation coil through the preset through hole 11a at the bottom flange 11. The area between the heat dissipation coil and the outer casing constitutes the heat exchange zone, which is assisted by liquid flow through the liquid inlet and liquid outlet.

[0030] As can be seen from the above description, the drive disk 46 plays the role of a core component.

[0031] The presence of the drive disc 46 provides lubricating oil for circulation, ensuring the internal circulation function of the lubricating oil. During operation, the drive disc 46's vertical axis and high-speed rotation accompanying the pump shaft 20 make its operational stability crucial. Therefore, this invention adds a limiting plate 61 with a friction plate 62, forming the aforementioned thrust bearing structure between the friction plate 62 and the drive disc 46. The clamping action of the friction plate 62 prevents vibrations generated during pump operation from increasing the clearance of the thrust bearing structure and effectively reduces the axial displacement of the pump shaft 20, ensuring the operational stability of the drive disc 46, eliminating safety hazards, and ensuring the normal and reliable operation of the pump. When actually installing the limiting plate 61, this invention incorporates an adjusting ring 63 and an adjusting screw 64. Tightening the adjusting screw 64 controls the height of the adjusting ring 63 relative to the annular groove, enabling controllable adjustment of the thrust of the drive disc 46. The adjusting ring 63 can form a rotary fit with the adjusting screw 64 through a stepped hole or through a bearing, etc. The design is relatively conventional and will not be described in detail here.

[0032] In reality, while the lubricant completes its internal circulation flow, a portion of it slowly seeps into the working medium zone a through the baffle seal assembly due to positive pressure. This positive pressure helps maintain the cleanliness of the lubrication and cooling zone b. More specifically, such as... Figure 1 and Figure 2 As shown, the top end of the pump shaft 20 is actually provided with a working medium zone a, and an impeller 30 is installed in the working medium zone a, thereby achieving the effect of conveying materials. To ensure the isolation between the working medium zone a and the lubrication and cooling zone b located in the pump casing 10, the present invention sequentially arranges a throttling sleeve 81 and a baffle sleeve 82 as primary throttling, and a labyrinth seal 83 as secondary throttling on the pump shaft 20. The specific installation positions are as follows: Figure 2 As shown.

[0033] Figure 2 As can be seen, the baffle sleeve 82 is installed on the pump shaft 20, while the throttling sleeve 81 is threaded onto the pump housing 10. The throttling sleeve 81 includes a main sleeve 81a and an extending extension sleeve 81b. The extension sleeve 81b extends into the large-diameter section of the baffle sleeve 82, so that the throttling sleeve 81 and the baffle sleeve 82 form a "]"-shaped flow channel structure. During operation, under the internal circulation action, some of the lubricating fluid will flow along the above-mentioned flow channel structure, through the labyrinth seal 83, and finally enter the working medium zone a. When the drive disc 46 fails to rotate, such as when the external motor 48 fails, causing the pump shaft 20 to decelerate or even stop, the lubrication cooling zone b loses pressure, and the pressure in the working medium zone a gradually exceeds the pressure in the lubrication cooling zone b, causing the working medium in the working medium zone a to leak back into the lubrication cooling zone b. At this point, the long clearance design between the throttling sleeve 81 and the pump shaft 20, as well as the long clearance formed between the throttling sleeve 81 and the baffle sleeve 82, effectively slows down the backflow velocity of the working medium, extending the time for the working medium to enter the lubrication and cooling zone b from the working medium zone a. Simultaneously, after passing through the long clearance between the throttling sleeve 81 and the pump shaft 20, the working medium first enters the baffle storage zone c for a reverse flow. This further decelerates the working medium and causes solid particles entrained in the working medium to settle and accumulate in the baffle storage zone c due to stalling. Subsequently, the long clearance formed between the throttling sleeve 81 and the baffle sleeve 82 acts as a final barrier, further preventing the diffusion of solid particles into the lubrication and cooling zone b, ultimately achieving the protection function for power components such as the motor 48 and even the entire circulating pump within the lubrication and cooling zone b.

[0034] As can be seen from the above, it is precisely due to the special fit between the throttling sleeve 81 and the baffle sleeve 82 that the delay effect on the working medium is achieved. However, simple delay always has a limited duration and obviously cannot ensure the long-term safe operation of the lubrication and cooling zone b; in particular, the lubrication and cooling zone b is not afraid of the working medium, but rather of the solid particles within it, which would greatly affect the normal lubrication of the workpiece within the lubrication and cooling zone b. Therefore, the dimensions of the baffle storage zone c, especially its axial length, become crucial; if the size is too large, there will obviously not be enough space inside the circulating pump, while if the size is too small, effective collection of solid particles will be impossible; and this, like the aforementioned harmfulness of solid particles, is currently being overlooked.

[0035] In view of this, the present invention also proposes a method for calculating the axial length h of the baffled storage area c, the specific steps of which are as follows: S1. Calculate the volume of solid particles settling per minute when solid particles enter the baffled storage zone c using the following formula. :

[0036] in: V is the settling velocity of the solid particles, in m / s; S is the cross-sectional area of ​​the folded storage region c, in units of... ; S2. Calculate the volume c of the folded storage area using the following formula. :

[0037] in: T is the time from when the lubricating fluid loses pressure until the solid particles enter the lubrication and cooling zone b, in minutes; S3. Calculate the axial length h of the baffled storage area c using the following formula:

[0038] in: R1 is the radius of the mating point of the pump shaft 20, in meters; R2 is the radius of the large aperture section, in meters.

[0039] In actual calculations, the radial gaps between the inner wall of the large-diameter section and the outer wall of the baffle sleeve 82, and between the inner wall of the throttling sleeve 81 and the outer wall of the pump shaft 20, are typically taken as 0.5 mm. The length-to-diameter ratio at the corresponding radial gap is 1.2 to 1.5 times that of the radial gap. Based on a shaft diameter of 76 mm, the length of the corresponding radial gap is 91.2 mm to 114 mm. The settling velocity of solid particles can be directly measured. After the material settles through the throttling sleeve 81, it enters the baffle storage area c. According to the actual testing requirements, after the lubricant supply is cut off, it is usually required that solid particles should not enter the motor 48 area, i.e., the lubrication and cooling area b, within 20 minutes. Therefore, the baffle storage area c is required to be able to store particles that have settled within at least 20 minutes. At this point, it is clear that the cross-sectional area of ​​the baffle storage zone c, the time from lubricant depressurization to solid particles entering the lubrication and cooling zone b, the radius of the mating point of the pump shaft 20, and the radius of the large-diameter section are all known. Using the above calculation formula, the axial length of the baffle storage zone c can be obtained, and then the design and installation can proceed. Of course, the actual volume of the baffle storage zone c can also be obtained by multiplying the aforementioned cross-sectional area by this axial length, which can be used for subsequent simulation.

[0040] Furthermore, this invention also features a small annular protrusion on the back of the impeller 30, namely the pre-grinding section 31, with a diameter smaller than that of the labyrinth seal 83. This ensures that even if excessive wear of the drive disc 46 and friction plate 62 causes the thrust bearing structure to thin, the pump shaft 20 to sink, and the impeller 30 to sink, the impeller 30 will not directly rub against the pump casing 10. Instead, it will only rub against the labyrinth seal 83 through the pre-grinding section 31. Replacing the labyrinth seal 83 is obviously much cheaper and more convenient than replacing the entire impeller 30, making subsequent maintenance extremely convenient and cost-effective. Of course, the pre-grinding section 31 is preferably a thrust bearing.

[0041] Thus, through the above structure and calculation formula, the present invention can ensure that the equipment as a whole is safe for at least a specified period of time when an oil injection failure occurs. After the failure is removed, it can be used directly without disassembly and inspection. Only the deflection storage area c at the lower throttling sleeve 81 and the deflection sleeve 82 needs to be maintained. This obviously greatly improves the overall safety and reduces unnecessary waste of manpower and material resources, with remarkable results.

[0042] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0043] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0044] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A circulating pump with internal circulation cooling and lubrication function, comprising a pump casing (10) and a pump shaft (20) arranged in the inner cavity of the pump casing (10), wherein the inner cavity of the pump casing (10) is divided by a seal into a working medium zone (a) at the front for accommodating the impeller (30) and a lubrication and cooling zone (b) at the rear; characterized in that: The pump shaft (20) in the lubrication and cooling zone (b) is arranged sequentially from front to back with a front radial bearing (41), a front sealing ring (42), an isolation sleeve (43), a rear radial bearing (44), a rear sealing ring (45), a drive disc (46), a rear flange (47), and a bottom flange (11); the bottom flange (11) is assembled at the tail end of the pump casing (10) to seal the inner cavity of the pump casing (10), wherein: The front radial bearing (41) and the front sealing ring (42) are combined to form a front sealing seat for sealing the front end face of the isolation sleeve (43); the rear radial bearing (44) and the rear sealing ring (45) are combined to form a rear sealing seat for sealing the rear end face of the isolation sleeve (43); the front sealing seat, the rear sealing seat and the isolation sleeve (43) together form a sealed mounting cavity (b2) for accommodating the motor (48); the rear sealing ring (45) and the rear flange (47) are fixed to each other and the two together form a receiving cavity (b1) for accommodating the drive disc (46). A heat exchanger (50) is installed on the outer end face of the bottom flange (11). The coolant outlet of the heat exchanger (50) passes through the bottom flange (11) and connects to the inlet hole located in the pump shaft (20). The coolant passes through the radially arranged outlet hole (21) at the pump shaft (20), and is thrown into the radial hole (46a) in the drive disc (46) under the centrifugal force of the drive disc (46) and enters the receiving cavity (b1). Then it passes through the rear sealing ring (45). The fluid flows into the mounting cavity (b2) through the connecting hole (45a) and / or the rear radial bearing (44) clearance, and then into the cavity wall flow channel (b3) reserved between the isolation sleeve (43) and the inner cavity wall of the pump housing (10) through the front radial bearing (41) clearance. It then flows back to the bottom flange (11) through the cavity wall flow channel (b3), and then flows back to the coolant inlet of the heat exchanger (50) through the through hole (11a) at the bottom flange (11). The sealing element is a baffle sealing assembly; the baffle sealing assembly includes a throttling sleeve (81) and a baffle sleeve (82) coaxially sleeved on the pump shaft (20) and arranged sequentially from head to tail along the axial direction of the pump shaft (20). The throttling sleeve (81) is fixed on the pump housing (10) so that it can rotate coaxially relative to the baffle sleeve (82); the baffle sleeve (82) is located in front of the front radial bearing (41), and the cylindrical cavity of the baffle sleeve (82) is in the shape of a two-stage stepped hole. The small diameter section of the baffle sleeve (82) forms a fixed cavity for fixing the pump shaft (20). The large-diameter section of the flow sleeve (82) extends axially and fits around the outer wall of the throttling sleeve (81), so that the lubricating fluid can sequentially travel through the radial gap between the inner wall of the large-diameter section and the outer wall of the baffle sleeve (82), the axial space between the end of the throttling sleeve (81) and the shoulder of the baffle sleeve (82), and the radial gap between the inner wall of the throttling sleeve (81) and the outer wall of the pump shaft (20), and then enter the working medium area (a); the axial space between the end of the throttling sleeve (81) and the shoulder of the baffle sleeve (82) constitutes a baffle storage area (c) for temporarily storing solid particles.

2. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: The drive disk (46) is disc-shaped. The cavity walls of the corresponding receiving cavities (b1) at both ends of the drive disk (46) are arranged with slots. A limiting piece (61) is installed in the slot. A limiting groove is installed on the limiting piece (61). The friction piece (62) is located in the limiting groove. The friction piece (62) and the drive disk (46) form a thrust bearing structure.

3. A circulating pump with internal circulation cooling and lubrication function according to claim 2, characterized in that: An annular groove is arranged at the bottom of the slot and an adjusting ring (63) is placed inside the annular groove. The threaded section of the adjusting screw (64) that rotates and fits on the adjusting ring is fitted at the bottom of the annular groove. The limiting piece (61) is annular in shape, and a positioning protrusion is provided on the end of the limiting piece (61) facing the slot. The positioning protrusion abuts against the corresponding annular surface of the adjusting ring (63).

4. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: The heat exchanger (50) includes a heat dissipation coil, and the heat dissipation coil is covered with a barrel-shaped outer cover. The barrel opening of the outer cover is coaxially fitted at the outer end face of the bottom flange (11). The area between the outer cover and the heat dissipation coil constitutes a heat exchange area. A liquid inlet and a liquid outlet connecting the heat exchange area are arranged on the outer cover.

5. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: Both the front radial bearing (41) and the rear radial bearing (44) are sliding bearings; a drive source (70) for driving the motor (48) is arranged on the outer wall of the pump casing (10).

6. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: The throttling sleeve (81) includes a main sleeve (81a) as the main body and an extension sleeve (81b) extending axially from the end of the main sleeve (81a). The main sleeve (81a) is threaded onto the pump housing (10), and the extension sleeve (81b) extends into the large-diameter section to cooperate with the baffle sleeve to form the baffle storage area (c). The radial gap between the extension sleeve (81b) and the pump shaft (20) is greater than the radial gap between the main sleeve (81a) and the pump shaft (20).

7. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: A labyrinth seal (83) is also arranged on a section of pump shaft (20) between the throttling sleeve (81) and the working medium area (a). The labyrinth seal (83) and the pump casing (10) form a stop fit that restricts the labyrinth seal (83) from moving unidirectionally towards the working medium area (a). The cylindrical cavity of the labyrinth seal (83) is sealed at the outer wall of the pump shaft (20), and there is a gap between the tail end of the labyrinth seal (83) and the corresponding end of the throttling sleeve (81).

8. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: An impeller (30) is coaxially mounted on the pump shaft (20) in the working medium area (a); an annular pre-grinding section (31) is coaxially protruded on the back of the impeller (30), and the pre-grinding section (31) is a thrust bearing; the stop of the pre-grinding section (31) is fitted at the shoulder of the pump shaft (20), and there is a gap between the head end of the labyrinth seal (83) and the shoulder that allows lubricating fluid to pass through; the diameter of the pre-grinding section (31) is smaller than the diameter of the head end face of the labyrinth seal (83).

9. A circulating pump with internal circulation cooling and lubrication function according to claim 1, characterized in that: The radial gaps between the inner wall of the large-diameter section and the outer wall of the baffle sleeve (82) and between the inner wall of the throttling sleeve (81) and the outer wall of the pump shaft (20) are both 0.5 mm, and the length-to-diameter ratio at the corresponding radial gaps is 1.2 to 1.5 times that of the radial gaps; and the calculation steps for the axial length h of the baffle storage area (c) at the baffle sealing assembly are as follows: S1. Calculate the volume of solid particles settling per minute when solid particles enter the baffled storage zone (c) using the following formula. : in: V is the settling velocity of the solid particles, in m / s; S is the cross-sectional area of ​​the folded storage region (c), in units of... ; S2. Calculate the volume of the folded storage area (c) using the following formula. : in: T is the time from when the lubricating fluid loses pressure until the solid particles enter the lubrication and cooling zone (b), in minutes; S3. Calculate the axial length h of the baffled storage area (c) using the following formula: in: R1 is the radius of the mating point of the pump shaft (20), in meters; R2 is the radius of the large aperture section, in meters.

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