Mechanical Reverse Rotation Prevention Device for Canned Motor Pump

Abstract

A mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention comprises a rotor (110) that rotates together with the main shaft of the motor, a stator (120) provided at a first distance from the outer surface of the rotor (110), a plurality of hinges (130) provided parallel to the main shaft and positioned between the outer surface of the rotor (110) and the inner surface of the stator (120), and arranged at predetermined intervals on a circumference at a second distance from the outer surface of the rotor (110) that is half the first distance, and a plurality of wedges (140) rotatably coupled to the hinges (130) and rotate in one direction by receiving centrifugal force according to the flow direction of a fluid (F) provided in the space between the rotor (110) and the stator (120), wherein when rotating in the forward direction, a gap (D) is formed between the wedges (130) and the rotor (110). It is configured so that a fluid (F) can pass through, and when rotating in reverse, one end of the wedge (140) returns to a position where it contacts the outer surface of the rotor (110), and at the same time, the other end of the wedge (140) contacts the inner surface of the stator (120), thereby eliminating the gap (D) and limiting the reverse rotation of the rotor (110).

Description

Technology Field

[0001] The present invention relates to a mechanical reverse rotation prevention device for a canned motor pump, and more specifically, to a mechanical reverse rotation prevention device for a canned motor pump that does not require external power supply or lubricating oil supply and operates stably without additional auxiliary devices.

[0003] This achievement is the result of research conducted with funding from the government (Ministry of Science and ICT) and supported by the Innovation Small Modular Reactor Technology Development Group (No. RS-2023-00264749).

[0004] This work was supported by the Innovative Small Modular Reactor Development Agency grant funded by the Korea Government (MSIT) (No. RS-2023-00264749). Background Technology

[0006] In general, systems consisting of a motor and a pump utilize a method where the motor and pump are connected via a coupling to drive the pump. In this case, the anti-reverse device is typically installed on the motor side in the form of a ball bearing. Ball bearing devices require an external supply of lubricant and necessitate periodic replacement when they wear out. Therefore, maintenance and management are essential for these ball bearing-type anti-reverse devices.

[0007] A canned motor pump features a structure where the motor and pump are integrated into a single unit, and a key characteristic is that it eliminates fluid leakage due to the absence of a shaft seal. For this reason, it is primarily used in situations involving the handling of liquids that are dangerous if exposed to the outside, such as those containing radiation or hazardous substances. Canned motor pumps can guarantee high safety in such environments.

[0008] However, due to the structural characteristics of canned motor pumps, a problem arises where lubricants or bearing oil cannot be supplied externally. Conventional ball bearing-based anti-reverse devices are not suitable for this system and have limitations in their application to canned motor pumps. This is because ball bearing systems require lubrication and periodic maintenance due to wear, whereas such maintenance is impossible with canned motor pumps.

[0009] Korean Registered Patent No. 10-1580526, proposed as one of the existing technologies, suggests an actuator-type anti-reverse rotation device. However, this method requires electrical energy, and a problem may arise where the device does not operate if the power supply is cut off in the event of an accident. Furthermore, because it uses electrical energy, additional auxiliary devices such as sensors to check the direction of rotation, power supplies, and cables are required. These auxiliary devices require separate management and maintenance, and can make the system more complex.

[0010] Therefore, existing technologies face various problems due to issues with external lubricant supply and dependence on electrical energy. To address this, research is required on a mechanical anti-reverse device for canned motor pumps that eliminates the need for external power and lubricant supply and operates stably without additional auxiliary devices. Prior art literature

[0012] Korean Registered Patent No. 10-1580526 The problem to be solved

[0013] The objective of the present invention is to provide a mechanical anti-reverse rotation device applicable to a canned motor pump in which the motor and pump are combined as a single unit and the external lubricant supply is unnecessary.

[0014] In addition, the objective of the present invention is to provide a reverse rotation prevention device that does not use electrical energy and can operate stably even when the power supply is cut off.

[0015] In addition, the objective of the present invention is to provide a mechanical reverse rotation prevention device configured to fix a wedge to the rotor using a permanent magnet during reverse rotation and maintain a constant gap during forward rotation so that fluid can flow smoothly.

[0016] In addition, the objective of the present invention is to provide a mechanical reverse rotation prevention device for a canned motor pump that can guarantee performance by detecting wear and changes in the condition of the device in real time without external additional devices or maintenance. means of solving the problem

[0018] A mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention comprises a rotor (110) that rotates together with the main shaft of the motor, a stator (120) provided at a first distance from the outer surface of the rotor (110), a plurality of hinges (130) provided parallel to the main shaft and positioned between the outer surface of the rotor (110) and the inner surface of the stator (120), and arranged at predetermined intervals on a circumference at a second distance from the outer surface of the rotor (110) that is half the first distance, and a plurality of wedges (140) rotatably coupled to the hinges (130) and rotate in one direction by receiving centrifugal force according to the flow direction of a fluid (F) provided in the space between the rotor (110) and the stator (120), wherein when rotating in the forward direction, a gap (D) is formed between the wedges (130) and the rotor (110). It is configured so that a fluid (F) can pass through, and when rotating in reverse, one end of the wedge (140) returns to a position where it contacts the outer surface of the rotor (110), and at the same time, the other end of the wedge (140) contacts the inner surface of the stator (120), thereby eliminating the gap (D) and limiting the reverse rotation of the rotor (110).

[0019] In addition, the wedge (140) according to one embodiment of the present invention may have a maximum distance in a cross-section cut in a direction perpendicular to the hinge (130) that is longer than the first distance, and the tolerance may be greater than the tolerance of the stator (120).

[0020] Additionally, according to one embodiment of the present invention, a permanent magnet (150) is included inside the wedge (140) and the rotor (110), respectively. When the permanent magnet (150) rotates in the forward direction, the wedge (140) rotates in one direction around the hinge (130) by the repulsive force of the same pole (N-N pole) between the wedge (140) and the rotor (110) to maintain the gap (D), and when the wedge (140) rotates in the reverse direction, the wedge (140) rotates in the other direction around the hinge (130) by the repulsive force of the same pole (S-S pole) to bring the wedge (140) into contact with the rotor (110) so that the gap (D) disappears. The permanent magnet (150) is sealed, and the wedge (140) and the rotor (110) may be made of a non-magnetic material.

[0021] In addition, the reverse rotation prevention device according to one embodiment of the present invention further includes a sensor unit that monitors the state of the wedge (140) and the rotor (110), wherein the sensor unit measures the rotation angle of the wedge (140) and the rotation speed of the rotor (110) to detect wear and changes in state by comparing them with a preset normal operating state, and is configured to generate a warning signal based on a wear threshold Mth based on a wear index M calculated according to [Equation 1] below, and can generate a warning signal if M exceeds the threshold Mth.

[0022] [Mathematical Formula 1]

[0023]

[0024] (Here, M represents the wear index, Δθ represents the change in the rotation angle of the wedge (140), Δv represents the change in the speed of the rotor (110), and k₁ and k₂ represent the correction coefficients for each variable.) Effects of the invention

[0026] The mechanical reverse rotation prevention device for a canned motor pump according to one embodiment of the present invention has the effect of being applicable to a canned motor pump in which the motor and the pump are integrally combined without the need for external lubricating oil supply.

[0027] In addition, the mechanical anti-reverse device according to one embodiment of the present invention does not use electrical energy and has the effect of operating stably even when the power supply is cut off.

[0028] In addition, the anti-reverse rotation device according to one embodiment of the present invention has the effect of ensuring smooth fluid flow by using a permanent magnet to fix a wedge to the rotor during reverse rotation and maintaining a constant gap during forward rotation.

[0029] In addition, the mechanical reverse rotation prevention device of a canned motor pump according to one embodiment of the present invention has the effect of ensuring performance by detecting the wear status and changes of the device in real time without external additional devices or maintenance. Brief explanation of the drawing

[0031] FIG. 1 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention. FIG. 2 is a cross-sectional perspective view illustrating a mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention. FIG. 3 is an exploded view of a mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a forward-rotating canned motor pump according to an embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a forward-rotating canned motor pump including a permanent magnet according to an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a reverse-rotating canned motor pump including a permanent magnet according to an embodiment of the present invention. Specific details for implementing the invention

[0032] Specific embodiments of the present invention will be described in detail below with reference to the drawings. However, the concept of the present invention is not limited to the embodiments presented. Those skilled in the art who understand the concept of the present invention may easily propose other inventions that are inferior or other embodiments included within the scope of the concept of the present invention by adding, changing, or deleting other components within the same scope of the concept, and such are also to be considered to be included within the scope of the concept of the present invention.

[0033] Hereinafter, the mechanical reverse rotation prevention device (100) of the canned motor pump of the present invention will be described in detail with reference to the attached FIGS. 1 to 6.

[0035] FIG. 1 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention, FIG. 2 is a cross-sectional perspective view illustrating a mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention, FIG. 3 is an exploded view of a mechanical reverse rotation prevention device for a canned motor pump according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a forward-rotating canned motor pump according to an embodiment of the present invention.

[0037] Referring to FIGS. 1 to 4, a reverse rotation prevention device (100) according to an embodiment of the present invention may include a rotor (110), a stator (120), a plurality of hinges (130), and a plurality of wedges (140).

[0038] The rotor (110) can rotate together with the main shaft of the motor.

[0039] The stator (120) can be provided at a first distance from the outer surface of the rotor (110).

[0040] A plurality of hinges (130) are provided parallel to the main axis and are located between the outer surface of the rotor (110) and the inner surface of the stator (120), and may be arranged at predetermined intervals on a circumference spaced from the outer surface of the rotor (110) by a second distance which is half the first distance. The hinges (130) are parts that connect the wedge (140) so that it can rotate between the rotor (110) and the stator (120). The hinges (130) can serve as an axis that allows the wedge (140) to rotate in one direction by receiving the centrifugal force of the fluid. In addition, the hinges (130) can ensure stable operation centered on the rotation of the wedge (140). The hinges (130) can be made of a highly durable material and can minimize wear even during long-term use of the device.

[0041] A plurality of wedges (140) are rotatably coupled to the hinge (130) and can rotate in one direction by receiving centrifugal force according to the flow direction of the fluid (F) provided in the space between the rotor (110) and the stator (120). The wedges (140) may be provided in the space between a pair of bearings coupled to the main shaft, such that the longest distance in the cross-section cut perpendicular to the hinge (130) is longer than the first distance. Of course, the rotor (110), stator (120), hinge (130), and wedges (140) may all be provided in the space between the pair of bearings. By providing the rotor (110), stator (120), hinge (130), and wedges (140) in the space between the bearings, the bearings can be concentric. The above bearing may be provided as a dynamic pressure and hydrostatic pressure sleeve bearing, and the surface of the bearing may be treated with an overlay weld build-up coating and a DLC coating.

[0042] Additionally, the tolerance of the wedge (140) may be larger than the tolerance of the bearing. Furthermore, the wedge (140) may be rotatably coupled to the hinge (130) and rotate in one direction according to the flow of fluid. The wedge (140) may control the flow of fluid by receiving centrifugal force and rotating to form or eliminate a gap (D) between the rotor (110) and the stator (120). The wedge (140) may be made of a material with excellent wear resistance and may be designed to withstand impact and wear occurring during rotation.

[0043] Additionally, when rotating forward, a gap (D) can be formed between the wedge (130) and the rotor (110) so that fluid (F) can pass through.

[0044] Additionally, when rotating in reverse, one end of the wedge (140) returns to a position where it contacts the outer surface of the rotor (110), and at the same time, the other end of the wedge (140) contacts the inner surface of the stator (120), thereby eliminating the gap (D) and limiting the reverse rotation of the rotor (110).

[0046] Next, with reference to FIGS. 5 and FIGS. 6, we will examine a reverse rotation prevention device (100) including a permanent magnet (150).

[0047] FIG. 5 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a forward-rotating canned motor pump including a permanent magnet according to an embodiment of the present invention, and FIG. 6 is a cross-sectional view illustrating a mechanical reverse rotation prevention device for a reverse-rotating canned motor pump including a permanent magnet according to an embodiment of the present invention.

[0048] Referring to FIGS. 5 and 6, a permanent magnet (150) may be included inside the wedge (140) and the rotor (110), respectively. When the permanent magnet (150) rotates in the forward direction, the wedge (140) rotates in one direction around the hinge (130) by means of a repulsive force of the same pole (N-N pole) between the wedge (140) and the rotor (110), thereby maintaining the gap (D).

[0049] When rotating in the reverse direction, the wedge (140) can be rotated in the opposite direction around the hinge (130) by the repulsive force of the same pole (S pole-S pole) to bring the wedge (140) into contact with the rotor (110), thereby eliminating the gap (D) and preventing reverse rotation. Additionally, the permanent magnet (150) may be sealed, and the wedge (140) and the rotor (110) may be made of a non-magnetic material. The permanent magnet (150) may be contained inside the wedge (140) and the rotor (110), respectively, to control the rotation of the wedge. The permanent magnet (150) may be sealed with a material having excellent durability and corrosion resistance, thereby improving the lifespan and stability of the device.

[0050] In addition, the permanent magnet (150) is positioned at an appropriate interval on the inside and outside of the wedge (140) and the rotor (110) to precisely control the rotational movement of the wedge (140) in accordance with forward and reverse rotation situations. The magnet is configured to provide an accurate repulsive force between the wedge and the rotor, thereby enabling the gap (D) to be quickly eliminated during reverse rotation without obstructing the flow of fluid.

[0051] In addition, the permanent magnet (150) is designed to operate stably in high temperature and high pressure environments, and a corrosion-resistant coating may be applied to prevent corrosion. As a result, the lifespan of the device can be extended and maintenance requirements minimized.

[0052] The above permanent magnet (150) has the characteristic of not requiring electrical energy, which allows the device to operate stably without an external power supply. This acts as an important factor that enables the canned motor pump to maintain its anti-reverse rotation performance even when the external power is cut off.

[0054] In addition, although not shown in the drawings, the mechanical reverse rotation prevention device (100) of a canned motor pump according to one embodiment of the present invention may further include a sensor unit (not shown) for monitoring the condition of the wedge (140) and the rotor (110).

[0055] The sensor unit measures the rotation angle of the wedge (140) and the rotation speed of the rotor (110), detects wear and changes in state by comparing with a preset normal operating state, and is configured to generate a warning signal based on a wear threshold Mth based on a wear index M calculated according to [Equation 1] below, and can generate a warning signal if M exceeds the threshold Mth.

[0056] [Mathematical Formula 1]

[0057]

[0058] (Here, M represents the wear index, Δθ represents the change in the rotation angle of the wedge (140), Δv represents the change in the speed of the rotor (110), and k₁ and k₂ represent the correction coefficients for each variable.)

[0059] Additionally, the sensor unit can measure the rotation angle and speed in real time through precision sensors placed on the wedge (140) and the rotor (110), respectively. These sensors may include optical sensors, gyroscope sensors, or Hall sensors, and can detect minute changes in the rotation angle of the wedge (140) and changes in the speed of the rotor (110) to track the movement and wear condition of the rotor with great precision. The sensor unit transmits the measured data to a central control unit to compare and analyze it with preset normal operating values, and can detect changes in the operating state in real time.

[0060] In addition, the sensor unit [calculates] the 'expected wear index M' according to [Equation 2] based on the change in rotation angle (Δθ) of the wedge (140) and the change in speed (Δv) of the rotor (110). pred It can calculate '. This mathematical formula is designed to predict the future wear state of the device based not only on the current rotational state but also on the device's past data.

[0061] [Mathematical Formula 2]

[0062]

[0063] Here, M pred represents the expected wear index, Δθ is the amount of change in the rotation angle of the wedge (140), Δv is the amount of change in the speed of the rotor (110), α1 and α2 are correction coefficients for the change in rotation angle and speed, M is the previously calculated wear index, β is a coefficient representing the rate of change of the wear index over time, and T represents the time range to be analyzed.

[0064] The following [Equation 2] can be used to predict the future wear state based on past wear data as well as the current state of the wedge (140). Through this, the sensor unit can predict the wear of the wedge (140) and the rotor (110) and accurately determine when pre-maintenance is required.

[0065] Based on this predicted data, the sensor unit can not only generate a warning signal but also output an adjustment signal to maintain optimal operating conditions of the device. This adjustment signal is transmitted to a central control unit and can be used to adjust the rotational speed of the machine or control the flow of fluid. Through such functions, the device can perform preventive maintenance against wear and tear, as well as maximize the efficiency of the device.

[0066] In addition, the sensor unit records all operating and wear states of the device through a data logging function, enabling the analysis of long-term performance changes based on this data. This data can be integrated with a cloud-based remote monitoring system, allowing users to check the device status in real time via mobile devices or computers.

[0067] In this way, the sensor unit linked with the remote monitoring system can automatically plan a maintenance schedule and prepare in advance for the replacement of necessary parts before wear reaches a critical threshold.

[0068] The sensor unit can be protected by a durable material to ensure reliable operation even in high-temperature and high-pressure environments, thereby maintaining the safety of the device, particularly in environments handling hazardous liquids such as canned motor pumps. Additionally, the sensor unit may include a function to safely store data even when the power is cut off, and to automatically recover and restart operation upon power restoration.

[0070] As described above, according to one embodiment of the present invention, it is applicable to a canned motor pump in which the motor and the pump are integrally combined without the need for external lubricating oil supply, does not require electrical energy, and has the effect of operating stably even when the power supply is cut off.

[0071] In addition, the anti-reverse rotation device according to one embodiment of the present invention uses a permanent magnet to fix a wedge to the rotor during reverse rotation and maintains a constant gap during forward rotation, thereby ensuring a smooth flow of fluid.

[0072] In addition, the mechanical reverse rotation prevention device of a canned motor pump according to one embodiment of the present invention has the effect of ensuring performance by detecting the wear status and changes of the device in real time without external additional devices or maintenance.

[0074] As described above, although an embodiment of the present invention has been explained by limited embodiments and drawings, the embodiment of the present invention is not limited to the embodiments described above, and various modifications and variations are possible from this description by those skilled in the art to which the present invention pertains. Accordingly, an embodiment of the present invention should be understood only by the claims described below, and all equivalent or analogous variations thereof shall be considered to be within the scope of the inventive concept. Explanation of the symbols

[0076] 100: Mechanical anti-reverse device for canned motor pumps 110: Rotor 120: Stator 130: Hinge 140: Wedge 150: Permanent magnet D: Gap F: Fluid

Claims

Claim 1 A rotor (110) that rotates together with the main shaft of a motor; a stator (120) provided at a first distance from the outer surface of the rotor (110); a plurality of hinges (130) provided parallel to the main shaft, located between the outer surface of the rotor (110) and the inner surface of the stator (120), and arranged at predetermined intervals on a circumference at a second distance from the outer surface of the rotor (110) that is half the first distance; and a plurality of wedges (140) rotatably coupled to the hinges (130) and rotate in one direction by receiving centrifugal force according to the flow direction of a fluid (F) provided in the space between the rotor (110) and the stator (120). A reverse rotation prevention device comprising, wherein, when rotating in the forward direction, a gap (D) is formed between the wedge (130) and the rotor (110) so that a fluid (F) can pass through, and when rotating in the reverse direction, one end of the wedge (140) returns to a position where it contacts the outer surface of the rotor (110) at the same time, the other end of the wedge (140) contacts the inner surface of the stator (120), thereby eliminating the gap (D) and restricting reverse rotation of the rotor (110). Claim 2 In claim 1, the wedge (140) is characterized in that the longest distance in the cross-section cut in a direction perpendicular to the hinge (130) is longer than the first distance, is provided in the space between a pair of bearings coupled to the main shaft, and has a tolerance greater than the tolerance of the bearings. Claim 3 In claim 2, a permanent magnet (150) is included inside each of the wedge (140) and the rotor (110), and when rotating in the forward direction, the permanent magnet (150) rotates the wedge (140) in one direction around the hinge (130) by a repulsive force of the same pole (N-N pole) between the wedge (140) and the rotor (110) to maintain the gap (D), and when rotating in the reverse direction, rotates the wedge (140) in the other direction around the hinge (130) by a repulsive force of the same pole (S-S pole) to bring the wedge (140) into contact with the rotor (110) so that the gap (D) disappears, and the permanent magnet (150) is sealed, and the wedge (140) and the rotor (110) are made of a non-magnetic material, characterized by a reverse rotation prevention device. Claim 4 In paragraph 3, the anti-reverse rotation device further comprises a sensor unit for monitoring the state of the wedge (140) and the rotor (110); wherein the sensor unit measures the rotation angle of the wedge (140) and the rotation speed of the rotor (110), detects wear and changes in state by comparing them with a preset normal operating state, and is configured to generate a warning signal based on a wear threshold Mth based on a wear index M calculated according to [Equation 1] below, and generates a warning signal when M exceeds the threshold Mth. (Here, M represents the wear index, Δθ represents the change in the rotation angle of the wedge (140), Δv represents the change in the speed of the rotor (110), and k₁ and k₂ represent the correction coefficients for each variable.)

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