Automatic grinding device for hub sealing surface of heavy water reactor mechanical sealing structure

Abstract

The invention discloses an automatic grinding device for a sealing surface of a hub of a heavy water reactor mechanical sealing structure, and belongs to the technical field of nuclear power station sealing equipment. The device comprises a base plate, a grinding head assembly, a clamping assembly, a transmission assembly and an electric control system, wherein the grinding head assembly, the clamping assembly, the transmission assembly and the electric control system are installed on the base plate, and the distance between the upper surface of the grinding head assembly and the lower surface of the base plate is smaller than 50 mm. The grinding head assembly is used for grinding the hub sealing face of a workpiece to be machined, the clamping assembly is used for clamping and positioning the hub outer edge of the workpiece to be machined, the transmission assembly is used for providing transmission power, and the distance between the upper surface of the grinding head assembly and the lower surface of the base plate is smaller than 50 mm. Therefore, the grinding device can be placed in a narrow space of 50 mm between the hub and the end part, clamping and centering of the device and grinding of the sealing face are achieved, and the engineering requirement for grinding and repairing the conical sealing face of the hub under the working condition that a heavy water reactor mechanical sealing mechanism is implemented on site is met.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant sealing equipment, and in particular to an automatic grinding device for a hub sealing surface of a heavy water reactor mechanical sealing structure, and further to an automatic grinding device for a high-pressure self-tightening flange sealing surface in a mechanical sealing mechanism of a heavy water reactor nuclear power plant. Background Art

[0002] The core of a heavy water reactor nuclear power plant consists of hundreds of fuel channels, which are distributed in a tightly packed manner. The space environment is small, the diameter of each fuel channel is less than 200mm, the center distance is less than 300mm, and the minimum distance between fuel channels is about 100mm. The distribution of fuel channels can be seen in Figure 1 The inlet and outlet of the fuel channel are connected to the water supply pipe through a high-pressure self-tightening flange. This high-pressure self-tightening flange belongs to a mechanical sealing mechanism, which is composed of an end component, a sealing ring, a hub (or flange) and a ferrule flange, etc., see Figure 2 As shown. The sealing surface of the end component and the sealing lip of the sealing ring form a pair of sealing pairs, and the sealing surface of the wheel hub and the sealing lip of the sealing ring form a pair of sealing pairs. By tightening the bolts, the ferrule is driven to press the wheel hub, so that the upper flange and the end component clamp the sealing ring, and the mechanical seal is achieved by the sealing lip of the sealing ring and the upper and lower sealing surfaces. As the pressure boundary of the fuel channel of the heavy water reactor unit, once the high-pressure self-tightening flange leaks, it will directly affect the safe and stable operation of the unit.

[0003] The wheel hub is made of SA105 steel, which has high strength. Its sealing surface is located in the area about 10mm high at the opening. Figure 3 As shown, the sealing surface is a conical surface as a whole, which forms a sealing contact pair with the sealing lip of the sealing ring, and achieves sealing by relying on the elastic deformation of the sealing lip and the principle of mechanical sealing.

[0004] Mechanical sealing mechanisms such as high-pressure self-tightening flanges serve as the pressure boundary of the fuel channel of heavy water reactor units. They have been in service for a long time in harsh environments such as high temperature, high pressure, and boric acid water media. They are prone to the following two types of damage: one is pitting corrosion and mechanical vibration wear of the sealing surface caused by corrosion; the other is scratches on the sealing surface due to improper operation during assembly. These damages may cause contact failure of the seal during long-term operation, and then cause leakage of the high-pressure self-tightening flange. Therefore, once the hub sealing surface is found to be damaged during the inspection and maintenance of the high-pressure self-tightening flange, the sealing surface needs to be repaired to ensure the sealing of the mechanical sealing mechanism. According to the actual situation of the damage, the repair method is also different. Among them, for scratches, wear and shallow corrosion points, it is necessary to grind and polish the sealing surface by grinding to remove the damage that affects the seal. However, since the fuel channel cannot be disassembled, the repair work of the hub sealing surface must be completed on-site in a radioactive environment; at the same time, due to the small space in which the high-pressure self-tightening flange is located, the hub and the end parts can only be pulled apart by about 50mm at most, which makes it difficult to repair by manual grinding, and the manual grinding method cannot guarantee the uniformity and accuracy of the sealing surface size; in addition, to ensure the stability of the grinding process and the uniformity of the circumferential direction, the grinding equipment must be firmly clamped on the hub and the coaxiality with the hub sealing surface must be ensured as much as possible. These characteristics determine that the grinding equipment for the hub sealing surface must be able to work in a small and complex space around the mechanical sealing mechanism, and not interfere with the surrounding components and other parts of the component. At the same time, the device is used in a radioactive environment, requiring the device to be light, easy to load and unload, short in time and stable. At the same time, the grinding equipment needs to be fastened and fixed to the hub and centered to ensure the stability and uniformity of the grinding process.

[0005] Therefore, it is necessary to design a special automatic grinding device for the hub sealing surface of the mechanical seal mechanism to realize the grinding work of the sealing surface. Summary of the invention

[0006] The purpose of the present invention is to provide an automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal mechanism. The device aims to realize automatic grinding of the hub sealing surface to restore the surface roughness and dimensional uniformity of the hub sealing surface, thereby ensuring the sealing performance of the mechanical seal mechanism, providing an important grinding function for the repair of the hub sealing surface of the heavy water reactor mechanical seal mechanism, and providing an important processing tool for on-site grinding and repair of the hub sealing surface of the heavy water reactor mechanical seal mechanism.

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] The present invention provides an automatic grinding device for a hub sealing surface of a heavy water reactor mechanical seal structure, comprising:

[0009] Chassis;

[0010] A grinding head assembly, the grinding head assembly is mounted on the chassis, and the grinding head assembly is used to grind the hub sealing surface of the workpiece to be processed; the distance between the upper surface of the grinding head assembly and the lower surface of the chassis is less than 50 mm;

[0011] A clamping assembly, wherein the clamping assembly is mounted on the chassis and connected to the grinding head assembly, and the clamping assembly is used to clamp and position the outer edge of the hub of the workpiece to be processed and to center the hub so as to install and fix the mechanical seal structure of the heavy water reactor in a narrow space on-site environment;

[0012] A transmission assembly, the transmission assembly is mounted on the chassis, the transmission assembly is connected to the clamping assembly, and the transmission assembly is used to provide transmission power for grinding the hub sealing surface;

[0013] An electric control system is connected to the tail of the transmission assembly, and is used to control the operation of the grinding head assembly, the clamping assembly and the transmission assembly.

[0014] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the chassis includes: a shell and a disc, the shell is installed and fixed on the side end surface of the disc, and a circular hole for connecting the grinding head assembly is opened at the center of the disc.

[0015] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the chassis also includes a limit ring, which is used to axially limit the hub sealing surface of the workpiece to be processed, and the limit ring is installed on the bottom end surface of the disc, and the limit ring is arranged close to the circular hole.

[0016] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the grinding head assembly includes: a rotating shaft, a chuck, a latch, a spring, a grinding head housing and a grinding head.

[0017] The output end of the rotating shaft passes through the chassis and is connected to the transmission assembly;

[0018] The chuck is fixed at the input end of the rotating shaft, a groove is provided along the circumference of the chuck, and the spring is fixed in the groove of the chuck through the latch;

[0019] The inner side of the grinding head shell is provided with a slot for installing the chuck, the grinding head is fixed to the chuck by the latch, and the grinding head is installed on the outer side of the grinding head shell. Further, in the automatic grinding device for the hub sealing surface of the mechanical seal structure of a heavy water reactor, the clamping assembly includes: a second motor, a motor fixing seat and a claw head,

[0020] The second motor is installed in the motor fixing seat, and the motor fixing seat is fixed on the chassis, and the claw head is connected to the output end of the second motor.

[0021] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the number of the second motors is four groups, and the second motors are evenly installed on the chassis.

[0022] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the number of the claws is four, and the four claws position the outer edge of the hub of the workpiece to be processed.

[0023] Furthermore, in the automatic grinding device for the hub sealing surface of the mechanical seal structure of a heavy water reactor, the transmission assembly includes: a driven wheel, a conveyor belt, a driving wheel, a motor fixing plate, a transmission gear set, a first motor, a motor housing, a transmission rod, a main rotating shaft, a protective sleeve and a heat sink,

[0024] The driven wheel and the driving wheel are connected via a conveyor belt, the driven wheel is mounted on the chassis, and the driven wheel is connected to the grinding head assembly;

[0025] The driving wheel is mounted on the motor fixing plate, the motor fixing plate is mounted on the chassis, the motor fixing plate is mounted on the motor housing, the first motor is mounted on the motor housing, and the first motor is connected to the driving shaft, the driving shaft is drivingly connected to the transmission gear set, the transmission gear set and the driving wheel are both sleeved on the transmission rod, and the transmission gear set drives the driving wheel to rotate via the transmission rod, the protective cover is mounted on the motor housing, the protective cover is used for fixing and protecting the main rotating shaft, and the heat sink is mounted on the motor housing and is used for heat dissipation.

[0026] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the transmission assembly also includes: a connecting plug, which is installed on the first motor and connected to the electronic control system through a communication line.

[0027] Furthermore, in the automatic grinding device for the hub sealing surface of the heavy water reactor mechanical seal structure, the single grinding amount of the automatic grinding device is less than 0.01 mm.

[0028] The present invention has the following beneficial effects:

[0029] The automatic grinding device for the hub sealing surface of the mechanical seal mechanism of a heavy water reactor provided by the present invention realizes the grinding of the hub sealing surface of the workpiece to be processed through the grinding head assembly, and the grinding head of the grinding head assembly can float up and down to achieve the fit with the conical sealing surface to be processed, thereby ensuring the uniformity of the processing. The clamping assembly is used to achieve the clamping and positioning of the outer edge of the hub of the workpiece to be processed, and the transmission assembly is used to provide transmission power. The distance between the upper surface of the grinding head assembly and the lower surface of the chassis is less than 50mm, so it can be placed in the narrow space of 50mm between the hub and the end component, thereby achieving the clamping, centering and sealing surface grinding of the device, solving the engineering needs of grinding and repairing the conical sealing surface of the hub under the on-site implementation conditions of the mechanical seal mechanism of the heavy water reactor.

[0030] The automatic grinding device for the hub sealing surface of the mechanical seal mechanism of a heavy water reactor provided by the present invention has a simple and light structure, avoids redundant structures, is lightweight and portable as a whole, is simple to load and unload and to operate, can meet the requirements of rapid processing in a low-radiation environment, and has a stable grinding process, which meets the narrow space requirements for on-site repair of the hub sealing surface, realizes the grinding repair of the hub sealing surface of the mechanical seal mechanism of a heavy water reactor, and can be applied to the maintenance of the mechanical seal structure of a heavy water reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0032] Figure 1 It is a schematic diagram of fuel channel distribution in the background technology of the present invention;

[0033] Figure 2 It is a schematic diagram of a mechanical sealing mechanism in the background technology of the present invention;

[0034] Figure 3 A schematic diagram of a hub sealing surface of a mechanical sealing mechanism in the background technology of the present invention;

[0035] Figure 4 It is a schematic structural diagram of an automatic grinding device for a hub sealing surface of a mechanical seal structure of a heavy water reactor according to an embodiment of the present invention;

[0036] Figure 5 It is a structural schematic diagram of a chassis in an automatic grinding device for a hub sealing surface of a mechanical seal structure for a heavy water reactor according to an embodiment of the present invention;

[0037] Figure 6 A half-section schematic diagram of a grinding head assembly in an automatic grinding device for a hub sealing surface of a heavy water reactor mechanical seal structure according to an embodiment of the present invention;

[0038] Figure 7 It is a schematic structural diagram of a clamping assembly in an automatic grinding device for a hub sealing surface of a heavy water reactor mechanical seal structure according to an embodiment of the present invention;

[0039] Figure 8 It is a schematic structural diagram of a transmission assembly in an automatic grinding device for a hub sealing surface of a mechanical seal structure of a heavy water reactor according to an embodiment of the present invention;

[0040] Fig. 9 The figure is a schematic cross-sectional structure diagram of a transmission assembly in an automatic grinding device for a hub sealing surface of a mechanical seal structure of a heavy water reactor according to an embodiment of the present invention.

[0041] Marks and corresponding parts names in the attached drawings:

[0042] In the figure: 1-chassis, 2-grinding head assembly, 3-clamping assembly, 4-transmission assembly, 5-electronic control system, 6-housing, 7-disc, 8-limiting ring, 9-rotating shaft, 10-chuck, 11-latch, 12-spring, 13-grinding head housing, 14-grinding head, 15-claw head, 16-second motor, 17-motor fixing seat, 18-driven wheel, 19-conveyor belt, 20-driving wheel, 21-motor fixing plate, 22-transmission gear set, 23-first motor, 24-motor housing, 25-transmission rod, 26-main rotating shaft, 27-protective cover, 28-heat sink, 29-connecting plug. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example

[0046] Please refer to Figure 4-9 The embodiment of the present invention provides an automatic grinding device for a hub sealing surface of a heavy water reactor mechanical seal structure, comprising:

[0047] Chassis 1;

[0048] A grinding head assembly 2, the grinding head assembly 2 is mounted on the chassis 1, and the grinding head assembly 2 is used to grind the hub sealing surface of the workpiece to be processed; the distance between the upper surface of the grinding head assembly 2 and the lower surface of the chassis 1 is less than 50 mm;

[0049] A clamping assembly 3, which is mounted on the chassis 1 and connected to the grinding head assembly 2, and is used to clamp and position the outer edge of the hub of the workpiece to be processed and to center the hub so as to install and fix the mechanical seal structure of the heavy water reactor in a narrow space on-site environment;

[0050] Transmission assembly 4, which is mounted on chassis 1 and connected to clamping assembly 3, and is used to provide transmission power for grinding the sealing surface of the wheel hub;

[0051] The electric control system is connected to the tail of the transmission assembly 4 and is used to control the operation of the grinding head assembly 2, the clamping assembly 3 and the transmission assembly 4.

[0052] The automatic grinding device for the hub sealing surface of the mechanical seal mechanism of a heavy water reactor provided by the present invention realizes the grinding of the hub sealing surface of the workpiece to be processed through the grinding head assembly, and the grinding head of the grinding head assembly can float up and down to achieve the fit with the conical sealing surface to be processed, thereby ensuring the uniformity of the processing. The clamping assembly is used to achieve the clamping and positioning of the outer edge of the hub of the workpiece to be processed, and the transmission assembly is used to provide transmission power. The distance between the upper surface of the grinding head assembly and the lower surface of the chassis is less than 50mm, so it can be placed in the narrow space of 50mm between the hub and the end component, thereby achieving the clamping, centering and sealing surface grinding of the device, solving the engineering needs of grinding and repairing the conical sealing surface of the hub under the on-site implementation conditions of the mechanical seal mechanism of the heavy water reactor.

[0053] In some feasible embodiments, the chassis 1 includes: a shell 6 and a disc 7, the shell 6 is mounted and fixed on the side end surface of the disc 7, and a circular hole for connecting the grinding head assembly 2 is opened at the center of the disc 7. The shell 6 is formed in one piece by high-strength aluminum alloy, including a bottom shell, a side wall shell and a rectangular shell, the side wall shell is provided with circumferential threaded holes, and the side of the rectangular shell is provided with threaded holes, the disc 7 is fastened to the shell 6 by screws, and a circular hole is opened in the middle of the disc 7, which is specifically used to connect the rotating head to facilitate the passage of the rotating shaft 9.

[0054] In some feasible embodiments, the chassis 1 further includes a limiting ring 8, which is used to axially limit the hub sealing surface of the workpiece to be processed, and the limiting ring 8 is installed on the bottom end surface of the disc 7, and the limiting ring 8 is arranged close to the circular hole. The limiting ring 8 is fixed to the disc 7 by bolts, and is used to achieve axial limiting of the device and the hub sealing surface of the workpiece to be processed.

[0055] In some feasible embodiments, the grinding head assembly 2 includes: a rotating shaft 9, a chuck 10, a latch 11, a spring 12, a grinding head shell 13 and a grinding head 14. The output end of the rotating shaft 9 passes through the chassis 1 and is connected to the transmission assembly 4. The chuck 10 is fixed to the input end of the rotating shaft 9, and a groove is provided along the circumference of the chuck 10. The spring 12 is fixed in the groove of the chuck 10 through the latch 11. A slot for installing the chuck 10 is provided on the inner side of the grinding head shell 13. The grinding head 14 is fixed to the chuck 10 through the latch 11, and the grinding head 14 is installed on the outer side of the grinding head shell 13. The grinding head shell 13 floats up and down through the chuck 10, the latch 11 and the spring 12, and can drive the grinding head 13 to float up and down, so as to fit the conical sealing surface to be processed.

[0056] The outer side of the grinding head shell 13 is a conical surface, which can be replaced according to the angle of the conical sealing surface to be processed. The grinding head 14 is a conical structure made of grinding materials of different materials. The grinding head 14 can also be replaced with grinding sandpaper according to the grinding requirements and attached to the grinding head shell 13 to realize the processing of the conical sealing surface.

[0057] Specifically, the rotating shaft 9 passes through the chassis 1 of the disc 7 and is connected to the transmission assembly 4 for transmitting power; the chuck 10 is fixed to the rotating shaft 9 by a pin, and the latch 11 is fixed to the chuck 10 by spot welding. The spring 12 is fixed in the groove of the chuck 10 by the latch 11; the inner side of the grinding head shell 13 is circumferentially arranged with a slot and a limit pin, which is fixed to the latch 11 by the slot and axially limited by the spring 12; the grinding head 14 is composed of sandpaper or corundum, and is applied to the grinding head shell 13 by adhesive, and the grinding head 14 rotates at high speed to realize the grinding of the sealing surface. The latch 11 can be selected as a cross or a straight line. The material of the grinding head 14 can be selected as sandpaper or corundum, which can be adjusted according to the actual process requirements of the sealing surface to be processed, or can be adjusted according to the diameter, taper, and sealing surface height of the conical sealing surface to be processed.

[0058] In some feasible embodiments, the clamping assembly 3 includes: a second motor 16, a motor fixing seat 17 and a claw head 15,

[0059] The second motor 16 is installed in the motor fixing seat 17, and the motor fixing seat 17 is fixed on the chassis 1, and the claw head 15 is connected to the output end of the second motor 16. Specifically, the motor fixing seat 17 is fixed to the disc 7 of the chassis 1 by bolts, and the second motor 16 is fixed to the motor fixing seat 17 by bolts. The claw head 15 is connected to the output shaft of the second motor 16, and the outer edge of the wheel hub is clamped by the claw head 15.

[0060] In some feasible embodiments, the number of the second motors 16 is four, and the second motors 16 are evenly installed on the chassis 1 .

[0061] In some feasible ways, the number of claw heads 15 is four, and the four claw heads 15 are used to position the outer edge of the hub of the workpiece to be processed. The four sets of second motors 16 and the corresponding four claw heads 15 are controlled by the electronic control system to move in a coordinated manner, thereby driving the claw heads 15 to contract, making it easier to press the outer edge of the hub through the claw heads 15, and easier to achieve fixation with the outer edge of the hub through friction. In other embodiments of the present invention, the number and size of the claw heads 15 can be changed to adapt to different types of hubs (flanges) or flanges with conical sealing surfaces.

[0062] In some possible ways, refer to Figure 8-9 The transmission assembly 4 includes: a driven wheel 18, a driving wheel 20, a motor fixing plate 21, a transmission gear set 22, a first motor 23, a motor housing 24, a transmission rod 25, a main rotating shaft 26, a protective cover 27 and a heat sink 28.

[0063] The driven wheel 18 and the driving wheel 20 are connected via a conveyor belt 19, the driven wheel 18 is mounted on the chassis 1, and the driven wheel 18 is connected to the grinding head assembly 2;

[0064] The driving wheel 20 is mounted on the motor fixing plate 21, the motor fixing plate 21 is mounted on the chassis 1, the motor fixing plate 21 is mounted on the motor housing 24, the first motor 23 is mounted on the motor housing 24, and the output end of the first motor 23 is connected to the driving shaft 26. Preferably, the output end can be fixedly connected to the driving shaft 26, thereby driving the driving shaft 26 to rotate, and the transmission gear set 22 is sleeved and fixed on the driving shaft 26, and rotates with the rotation of the driving shaft 26. Preferably, the above-mentioned transmission gear set 22 can include two mutually meshing angular gears, one angular gear is sleeved on the driving shaft 26, and the other angular gear is sleeved on the transmission rod 25, the two are meshed, thereby driving the transmission rod 25 to rotate, and at the same time, the driving wheel 20 is also sleeved on the transmission rod 25 and can rotate with it.

[0065] Among them, the driven wheel 18 is a large wheel, which is fixed to the housing 6 of the chassis 1 through a bearing group and is connected to the rotating shaft 9 of the grinding head assembly 2; the driven wheel 18 is connected to the driving wheel 20 through a conveyor belt 19, and the driving wheel 20 is fixed to the motor fixing plate 21 through screws, and the motor fixing plate 21 is fixed to the chassis 1 through four groups of bolts. The motor housing 24 is fixed to the motor fixing plate 21 through bolts. The first motor 23 is connected to the motor housing 24 through a series of bolts. The first motor 23 includes a series of structures such as a radiator and a reducer, and transmits power to the driving wheel 20 through a transmission gear set 22. The first motor 23 is connected to the electronic control system through a connecting plug 29 and can transmit signals.

[0066] In some feasible embodiments, the transmission assembly 4 further includes: a connecting plug 29 , which is mounted on the first motor 23 , and the connecting plug 29 is connected to the electric control system via a communication line.

[0067] In some feasible ways, the single grinding amount of the automatic grinding device is less than 0.01 mm. Through the electronic control system, the time of each grinding is set to ensure that the single grinding amount is less than 0.01 mm to avoid over-grinding.

[0068] The automatic grinding device for the hub sealing surface of the mechanical seal structure of a heavy water reactor provided by the present invention has the following working principle:

[0069] (1) After roughly positioning the four-claw head of the clamping assembly and the outer edge of the hub of the workpiece to be processed, the second motor is started to drive the four-claw head to retract inward, thereby achieving clamping positioning and centering of the clamping assembly and the outer edge of the hub.

[0070] (2) The lower surface of the wheel hub of the workpiece to be processed is limited by a limiting ring, and it is ensured that the device has no horizontal freedom; the contact and compression between the grinding head and the sealing surface of the wheel hub of the workpiece to be processed are achieved by the spring rebound force; the vertical feeding and compression state of the spring is changed.

[0071] (3) The first motor is remotely controlled by the electronic control system to start, drive the small wheel to move, and drive the large wheel and the centering plate to rotate through the belt. The centering plate finally drives the grinding head to rotate. The outer surface of the grinding head is affixed with sandpaper of different mesh sizes or a replaceable diamond head.

[0072] (4) A high-speed rotating grinding head is used to grind the sealing surface using sandpaper or diamond abrasive head.

[0073] (5) Through the electronic control system, set the time for each grinding to ensure that the single grinding amount is less than 0.01mm to avoid over-grinding.

[0074] (6) According to the mesh size of different sandpaper or diamond grains, a series of repair work from rough grinding, fine grinding to polishing of the sealing surface can be achieved.

[0075] By utilizing the automatic grinding device for the hub sealing surface of the mechanical seal structure of a heavy water reactor provided by the present invention, the device can be installed in a narrow space with a maximum spacing of 50 mm between the hub and the end component of the mechanical seal structure of a heavy water reactor, and the clamping and fixing with the hub and the centering with the sealing surface can be achieved through a four-claw mechanism; the sealing surface can be ground under the condition of on-site hub sealing surface maintenance, and the uniformity of the grinding process can be ensured by the floating centering of the grinding head; the use of a sandpaper grinding head can ensure that the single grinding amount is 0.01 mm, and through a series of operations such as rough grinding, precision grinding, polishing, etc., the surface roughness of the ground sealing surface can reach less than 0.4 μm.

[0076] The automatic grinding device for the hub sealing surface of the mechanical seal structure of a heavy water reactor provided by the present invention is electrically driven, includes the functions of four-claw clamping positioning center and floating centering, has a stable clamping method, can be centered with the hub sealing surface, has a stable grinding process, and is uniform in the circumferential direction, meeting the processing requirements for grinding the hub sealing surface. The device has been used to complete the grinding and repair of the hub sealing surface on a 1:1 test device for the mechanical seal mechanism of the fuel channel of a CANDU-6 heavy water reactor, and can also be used for the grinding and repair of other conical sealing surfaces similar to flanges.

[0077] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure, characterized in that: include: Chassis (1); A grinding head assembly (2), the grinding head assembly (2) being mounted on the chassis (1), the grinding head assembly (2) being used to grind a hub sealing surface of a workpiece to be machined; the distance between the upper surface of the grinding head assembly (2) and the lower surface of the chassis (1) being less than 50 mm; A clamping assembly (3), the clamping assembly (3) being mounted on the chassis (1), and the clamping assembly (3) being connected to the grinding head assembly (2), the clamping assembly (3) being used to clamp, position and center the outer edge of the hub of the workpiece to be processed so as to achieve installation and fixation of the heavy water reactor mechanical seal structure in a narrow space on-site environment; A transmission assembly (4), the transmission assembly (4) being mounted on the chassis (1), the transmission assembly (4) being connected to the clamping assembly (3), and the transmission assembly (4) being used to provide transmission power for grinding the sealing surface of the wheel hub; An electric control system (5), the electric control system (5) is connected to the rear end of the transmission assembly (4), and the electric control system is used to control the operation of the grinding head assembly (2), the clamping assembly (3) and the transmission assembly (4).

2. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 1 is characterized in that: The chassis (1) comprises: a shell (6) and a disc (7); the shell (6) is mounted and fixed on the side end surface of the disc (7); and a circular hole for connecting the grinding head assembly (2) is provided at the center of the disc (7).

3. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 2 is characterized in that: The chassis (1) also includes a limiting ring (8), which is used to axially limit the hub sealing surface of the workpiece to be processed. The limiting ring (8) is installed on the bottom end surface of the disc (7), and the limiting ring (8) is arranged close to the circular hole.

4. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 1, characterized in that: The grinding head assembly (2) comprises: a rotating shaft (9), a chuck (10), a latch (11), a spring (12), a grinding head housing (13) and a grinding head (14). The output end of the rotating shaft (9) passes through the chassis (1) and is connected to the transmission assembly (4); The chuck (10) is fixed at the input end of the rotating shaft (9), a groove is provided along the circumference of the chuck (10), and the spring (12) is fixed in the groove of the chuck (10) through the latch (11); A slot for mounting the chuck (10) is provided on the inner side of the grinding head shell (13); the grinding head (14) is fixed to the chuck (10) via the latch (11); and the grinding head (14) is mounted on the outer side of the grinding head shell (13).

5. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 1, characterized in that: The clamping assembly (3) comprises: a claw head (15), a second motor (16) and a motor fixing seat (17). The second motor (16) is installed in the motor fixing seat (17), and the motor fixing seat (17) is fixed on the chassis (1), and the claw head (15) is connected to the output end of the second motor (16).

6. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 5, characterized in that: The number of the second motors (16) is four, and the second motors (16) are evenly mounted on the chassis (1).

7. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 6, characterized in that: The number of the claw heads (15) is four, and the four claw heads (15) are used to position the outer edge of the hub of the workpiece to be processed.

8. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 1, characterized in that: The transmission assembly (4) comprises: a driven wheel (18), a conveyor belt (19), a driving wheel (20), a motor fixing plate (21), a transmission gear set (22), a first motor (23), a motor housing (24), a transmission rod (25), a main rotating shaft (26), a protective sleeve (27) and a heat sink (28). The driven wheel (18) and the driving wheel (20) are connected via a conveyor belt (19), the driven wheel (18) is mounted on the chassis (1), and the driven wheel (18) is connected to the grinding head assembly (2); The driving wheel (20) is mounted on the motor fixing plate (21), the motor fixing plate (21) is mounted on the chassis (1), the motor fixing plate (21) is mounted on the motor housing (24), the first motor (23) is mounted on the motor housing (24), and the output end of the first motor (23) is connected to the driving shaft (26), the driving shaft (26) is in driving connection with the transmission gear set (22), the transmission gear set (22) and the driving wheel (20) are both sleeved on the transmission rod (25), and the transmission gear set (22) drives the driving wheel (20) to rotate through the transmission rod (25), the protective cover (27) is mounted on the motor housing (24), the protective cover (27) is used for fixing and protecting the main rotating shaft (26), and the heat sink (28) is mounted on the motor housing (24) and is used for heat dissipation.

9. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 8, characterized in that: The transmission assembly (4) further comprises: a connection plug (29), wherein the connection plug (29) is mounted on the first motor (23), and the connection plug (29) is connected to the electric control system (5) via a communication line.

10. The automatic grinding device for the hub sealing surface of a heavy water reactor mechanical seal structure according to claim 1, characterized in that: The single grinding amount of the automatic grinding device is less than 0.01 mm.

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