A canned pump internal circulation flow regulating structure and canned pump

Abstract

The present application relates to a canned pump internal circulation flow regulating structure and a canned pump, wherein the canned pump internal circulation flow regulating structure comprises: an impeller shaft, which is inserted into a canned sleeve, an axial through hole is provided in the center of the impeller shaft, and a radial throttle hole is provided on the side wall of the impeller shaft to communicate with the axial through hole; a temperature control valve is provided at the bottom end of the axial through hole; the canned sleeve has a cover plate through hole provided on the front cover plate, and a bottom bearing is installed at the bottom of the canned sleeve; the bottom bearing is sleeved on the end of the impeller shaft away from the canned pump inlet, and an opening is provided on the bottom bearing. The technical solution of the present application reasonably matches the requirements of motor heat dissipation under different working loads of the water pump, and can prevent or reduce the generation of condensed water.

Description

Technical Field

[0001] The utility model relates to the technical field of shielded pumps, in particular to a shielded pump internal circulation flow regulating structure and a shielded pump. Background Art

[0002] A canned motor pump is a centrifugal, sealless pump. Both the pump and drive motor are enclosed in a pressure vessel filled with the pumped medium. This pressure vessel has only static seals. Canned motor pumps eliminate the rotating shaft seals found in traditional centrifugal pumps, resulting in a completely leak-free system. Canned motor pumps are lubricated and dissipated heat by the pumped medium, eliminating the need for additional grease or cooling fans.

[0003] For canned motor pumps with internal circulation design, in order to ensure the cooling of canned motor and lubrication of bearings and thrust plates, so that canned motor pumps can work normally, such as Figure 1 As shown, the existing technical solutions are to directly open several fixed holes on the bearing or bearing seat, and the high pressure area medium in the pump cavity (such as Figure 1 The area indicated by the black arrow in the middle) is introduced into the inner cavity of the shielding sleeve through the through hole of the cover (such as Figure 1 The medium then flows from the shield chamber back to the pump impeller inlet (low-pressure area) through the hollow impeller shaft, achieving internal circulation. This internal circulation design utilizes a certain amount of liquid circulation to lubricate and cool the rotor, bearings, and other parts, removing heat. This gives shielded pumps their unique advantages, such as zero leakage and low noise, leading to their widespread use. Appropriate circulation volume design has a significant impact on the performance and lifespan of shielded pumps.

[0004] From the path of completing a liquid cycle, it can be concluded that the power for introducing the internal circulation liquid comes from the pressure difference of the pumped liquid, which requires a certain loss of water pump performance, but this is the property of the shielded pump and needs to be controlled within an appropriate level range.

[0005] When the water pump is operating in the high-load range (high flow rate), the motor generates a lot of heat. At this time, a large amount of liquid circulation is required to flow into the rotor shield cavity to remove the heat generated by the motor. When the water pump is operating in the low-load range (low flow rate), the motor generates less heat. At this time, a smaller amount of liquid circulation is required to avoid unnecessary performance loss. However, there is no control unit in the existing circulation loop design. When the water pump is operating at a low load, the liquid circulation volume is always higher than the circulation flow rate when the water pump is in the high-load area, resulting in performance loss. On the other hand, the existing circulation control loop cannot take into account the temperature factor. Under some application conditions, such as when the temperature of the liquid delivered by the pump is lower than the ambient temperature, the larger circulation volume will increase condensation on the outer wall of the shield sleeve, generate more condensed water inside the motor, and have an adverse effect on the life of the motor. Therefore, the existing internal circulation control loop is difficult to adapt to and balance the heat dissipation requirements of the water pump under different working loads, affecting the performance and life of the shielded water pump and limiting the applicable scenarios of the shielded water pump. Utility Model Content

[0006] The purpose of the utility model is to provide a canned pump internal circulation flow regulating structure and a canned pump, so as to regulate the flow of liquid circulating in the canned pump.

[0007] To achieve the above-mentioned purpose, the present invention provides a canned motor pump internal circulation flow regulating structure, comprising:

[0008] The impeller shaft is inserted into the shield sleeve, and has an axial through hole at its center and a radial throttle hole on its side wall that communicates with the axial through hole.

[0009] a temperature control valve, which is arranged at the bottom end of the axial through hole;

[0010] The shielding sleeve has a front cover plate with a cover plate through hole, and a bottom bearing installed at the bottom;

[0011] The bottom bearing is sleeved on an end of the impeller shaft away from the inlet of the shielded pump, and an opening is provided on the bottom bearing.

[0012] Optionally, the axial through hole is a multi-step hole, wherein the aperture of the multi-step hole increases step by step from the front end to the bottom end.

[0013] Optionally, the temperature control valve is arranged at the level with the largest aperture in the multi-step hole.

[0014] Optionally, the multi-step hole is a three-step hole.

[0015] Optionally, the radial throttling hole is opened on the side wall of the first-stage hole and / or the side wall of the second-stage hole, and the aperture of the first-stage hole is smaller than the aperture of the second-stage hole.

[0016] Optionally, the temperature control valve includes paraffin, a first shell, a diaphragm, a valve bonnet, a valve column, a return spring, a second shell and a plunger; paraffin is filled in the sealed space formed by the first shell and the diaphragm, the open end of the first shell is sleeved on the valve bonnet, the valve bonnet is sleeved on the valve column, one end of the valve column abuts the diaphragm and the other end abuts the plunger, the plunger is arranged in the second shell and can close the first opening of the second shell, and the return spring abuts between the plunger and the second opening limit part of the second shell.

[0017] Optionally, the first shell is made of copper.

[0018] Optionally, the temperature control valve includes a shell, a return spring, a memory spring and a plunger; the plunger is arranged in the shell and can close the internal fluid channel of the shell; the memory spring abuts between the plunger and the first opening limit portion of the shell; the return spring abuts between the plunger and the second opening limit portion of the shell.

[0019] An embodiment of the present utility model further provides a shielded pump, comprising the shielded pump internal circulation flow regulating structure provided by any embodiment.

[0020] Optionally, the shielded pump further includes an impeller, which is sleeved on one end of the impeller shaft close to the shielded pump inlet.

[0021] As can be seen from the above, the technical solution provided by the embodiment of the utility model is the shielded pump internal circulation flow regulating structure, which has at least two internal circulation loops in the shielding sleeve through the radial throttling holes on the side walls of the impeller shaft and the axial through hole through the center, and adjusts the internal circulation flow at different liquid temperatures by setting a temperature control valve, reasonably matching the motor heat dissipation requirements under different working loads of the water pump, and can prevent or reduce the generation of condensed water. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic cross-sectional view of a shielding screen in the prior art, including a partial enlarged view of the front end cover of the shielding sleeve;

[0023] Figure 2 This is a schematic cross-sectional view of a canned motor pump according to an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the inner circulation control loop provided by an embodiment of the present utility model;

[0025] Figure 4 This is a structural diagram of a temperature control valve provided by an embodiment of the present utility model;

[0026] Figure 5 It is a structural schematic diagram of another temperature control valve provided by an embodiment of the present utility model. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention, and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of it.

[0028] Some directional words are defined in the present invention. Unless otherwise stated, the directional words used, such as "up", "down", "left", "right", "inside" and "outside", are used for ease of understanding and therefore do not constitute a limitation on the scope of protection of the present invention.

[0029] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0030] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0031] The present invention provides a canned motor pump internal circulation flow regulating structure, such as Figure 2 ,include:

[0032] The impeller shaft 100 is inserted into the shield sleeve 200 and has an axial through hole 110 at its center and radial throttle holes 120 on its sidewall that communicate with the axial through hole 110.

[0033] a temperature control valve 300 , which is disposed at the bottom end of the axial through hole 110 ;

[0034] The shielding sleeve 200 has a front cover plate 210 with a cover plate through hole 211, and a bottom bearing 220 installed at the bottom;

[0035] The bottom bearing 220 is sleeved on an end of the impeller shaft 100 away from the inlet of the canned motor pump. An opening 221 is provided on the bottom bearing 220 .

[0036] Optionally, the axial through hole 110 is a multi-step hole, wherein the aperture of the multi-step hole increases step by step from the front end to the bottom end. The axial through hole 110 is set as a step hole, and the inner circulation control loop is set as the first loop and the second loop (such as Figure 3 ), where the second circuit is the main circuit and the first circuit is the auxiliary circuit. The second circuit has a greater current capacity than the first circuit. Figure 2 The red arrow in the middle indicates the direction of liquid flow in the inner circulation loop. A thermostatic valve is added to the second loop. This valve senses temperature changes in the liquid within the shielding sleeve and controls its opening and closing. When the thermostatic valve is closed, the first loop operates independently. Due to the throttling of the radial orifice, the flow rate is low, which is suitable for initial pump operation when the medium temperature is low and meets low motor cooling requirements. When the temperature inside the shielding sleeve reaches the set point, the thermostatic valve opens. The second loop is then opened to participate in the liquid circulation, increasing the inner circulation flow rate. Once opened, the first and second loops operate simultaneously to meet cooling requirements.

[0037] Optionally, the temperature control valve 300 is arranged at the level with the largest aperture in the multi-step hole.

[0038] Optionally, the multi-step hole is a three-step hole.

[0039] Optionally, the radial throttling hole 120 is opened on the side wall of the first-stage hole and / or the side wall of the second-stage hole, and the aperture of the first-stage hole is smaller than the aperture of the second-stage hole. Figure 2 The radial throttle hole 120 shown in the figure can be optionally located at the front end area and / or the rear end area of ​​the rotor. The radial throttle hole in the first circuit can be arranged in the front area of ​​the rotor. The characteristic of the radial throttle hole is that the flow area is the smallest in the control circuit. Considering the processability, the diameter can generally be designed to be 0.2-1mm, for example, it can be set to 0.5mm in diameter. The radial throttle hole can also be arranged in the rear end area of ​​the rotor, such as Figure 2 In order to increase the fluidity of the liquid in the shielding sleeve, radial throttling holes can also be arranged in the front and rear areas of the rotor.

[0040] Optional, such as Figure 4The temperature control valve 300 includes paraffin wax, a first housing 310, a diaphragm 320, a valve cap 330, a valve stem 340, a return spring 350, a second housing 360, and a plunger 370. Paraffin wax is filled in the sealed space formed by the first housing 310 and the diaphragm 320. The open end of the first housing 310 is fitted with the valve cap 330, which in turn is fitted with the valve stem 340. One end of the valve stem 340 abuts the diaphragm 320 and the other end abuts the plunger 370. The plunger 370 is disposed within the second housing 360 and can seal the first opening of the second housing 360. The return spring 370 abuts between the plunger 370 and a second opening limiter of the second housing 360. Optionally, the valve cap 330 and the valve stem 340 are each provided with a matching limiter, and a return spring 350 may also be provided between the limiters of the valve cap 330 and the valve stem 340.

[0041] Optionally, first housing 310 is made of copper, which is a good heat conductor and transfers the liquid temperature to the paraffin wax. When the liquid temperature rises to the melting point of the selected paraffin wax, the paraffin wax melts and expands. The resulting expansion stress deforms the diaphragm, causing the valve stem to move. This displacement of the valve stem in turn moves the plunger, thereby opening the passage.

[0042] Optional, such as Figure 5 The temperature control valve 300 includes a housing 410, a return spring 420, a memory spring 430, and a plunger 440. The plunger 440 is disposed within the housing 410 and can seal the internal fluid passage of the housing 410. The memory spring 430 abuts between the plunger 440 and a first opening stopper of the housing 410. The return spring 420 abuts between the plunger 440 and a second opening stopper of the housing 410. The memory spring can also expand and contract with heat to push the plunger to move and open the fluid passage. The structure of the return spring and plunger in this embodiment is consistent with that in the embodiment described above where a paraffin temperature bulb is used to open the fluid passage.

[0043] An embodiment of the present utility model further provides a shielded pump, comprising the shielded pump internal circulation flow regulating structure provided by any embodiment.

[0044] Optionally, the canned motor pump further includes an impeller 500 , which is sleeved on one end of the impeller shaft 100 close to the inlet of the canned motor pump.

[0045] As can be seen from the above, the technical solution provided by the embodiment of the utility model is the shielded pump internal circulation flow regulating structure, which has at least two internal circulation loops in the shielding sleeve through the radial throttling holes on the side walls of the impeller shaft and the axial through hole through the center, and adjusts the internal circulation flow at different liquid temperatures by setting a temperature control valve, so as to reasonably match the motor heat dissipation requirements under different working loads of the water pump, and prevent or reduce the generation of condensed water.

[0046] Although the present invention has been described in detail above through general explanations, specific embodiments, and experiments, it will be apparent to those skilled in the art that modifications or improvements may be made to the present invention. Therefore, such modifications or improvements, without departing from the spirit of the present invention, are within the scope of protection claimed herein.

Claims

1. A canned motor pump internal circulation flow regulating structure, characterized in that: include: The impeller shaft is inserted into the shielding sleeve, an axial through hole is provided at the center of the impeller shaft, and a radial throttling hole is provided on the side wall of the impeller shaft to communicate with the axial through hole; A temperature control valve, which is arranged at the bottom end of the axial through hole; The shielding sleeve has a front cover plate with a cover plate through hole, and a bottom bearing is installed at the bottom; The bottom bearing is sleeved on an end of the impeller shaft away from the inlet of the shielded pump, and an opening is arranged on the bottom bearing.

2. The canned motor pump internal circulation flow regulating structure according to claim 1 is characterized in that: The axial through hole is a multi-step hole, wherein the aperture of the multi-step hole increases step by step from the front end to the bottom end.

3. The canned motor pump internal circulation flow regulating structure according to claim 2 is characterized in that: The temperature control valve is arranged at the level with the largest aperture in the multi-step hole.

4. The canned motor pump internal circulation flow regulating structure according to claim 3 is characterized in that: The multi-step hole is a three-step hole.

5. The canned motor pump internal circulation flow regulating structure according to claim 4 is characterized in that: The radial throttling hole is opened on the side wall of the first-stage hole and / or the side wall of the second-stage hole, and the aperture of the first-stage hole is smaller than the aperture of the second-stage hole.

6. The canned motor pump internal circulation flow regulating structure according to claim 1 is characterized in that: The temperature control valve includes paraffin, a first shell, a diaphragm, a valve cap, a valve column, a return spring, a second shell and a plunger; paraffin is filled in the sealed space formed by the first shell and the diaphragm, the opening end of the first shell is sleeved with the valve cap, the valve cap is sleeved with the valve column, one end of the valve column abuts against the diaphragm and the other end abuts against the plunger, the plunger is arranged in the second shell and can close the first opening of the second shell, and the return spring abuts between the plunger and the second opening limit part of the second shell.

7. The canned motor pump internal circulation flow regulating structure according to claim 6 is characterized in that: The first shell is made of copper.

8. The canned motor pump internal circulation flow regulating structure according to claim 1 is characterized in that: The temperature control valve comprises a housing, a return spring, a memory spring and a plunger; the plunger is arranged in the housing and can close the internal fluid channel of the housing; The memory spring abuts between the plunger and a first opening limit portion of the housing; the return spring abuts between the plunger and a second opening limit portion of the housing.

9. A canned motor pump, characterized in that: The invention comprises the canned motor pump internal circulation flow regulating structure as described in any one of claims 1 to 8.

10. The canned motor pump according to claim 9, characterized in that: It also includes an impeller which is sleeved on one end of the impeller shaft close to the inlet of the shielded pump.

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