Nuclear main pump welding seam cutting device

Abstract

The invention discloses a welding seam cutting device for a nuclear main pump. The welding seam cutting device comprises a rotating mechanism, a lifting mechanism, a cutting mechanism and a cuttings collecting disc. Wherein the chassis bracket, the slewing bearing and the slewing bearing motor form a slewing mechanism; the electric cylinder and the connecting piece A form a lifting mechanism; the saw blade milling cutter, the connecting piece B and the milling cutter motor form a cutting mechanism; the lower part of the chassis bracket is directly and fixedly connected with the equipment stator, and the upper part is fixedly connected with the slewing bearing outer ring; an electric cylinder is fixed on the inner ring of the slewing bearing and rotates around the equipment stator along with the inner ring of the slewing bearing; a milling cutter motor and a milling cutter are fixed at the tail end of the electric cylinder and move up and down along with the movement of a telescopic rod of the electric cylinder; and the cuttings collecting disc is tensioned in the stator.

Description

Technical Field

[0001] The present invention is a nuclear main pump weld cutting device, belonging to the technical field of nuclear power equipment maintenance and manufacturing. Background Art

[0002] As the core equipment of the reactor coolant system of a nuclear power plant, the nuclear main pump is crucial for the stability and safety of its operation. The impeller is a key component in the nuclear main pump, and the method of welding nuts is often used to prevent the impeller from loosening. In the long-term high-temperature, high-pressure and irradiation environment, and when the impeller needs to be replaced due to engineering requirements, it is necessary to cut the nut welds used to lock the impeller. Traditional cutting equipment is difficult to adapt to the narrow and complex internal space structure of the nuclear main pump, and it is impossible to accurately reach the position of the fixed impeller nut weld for cutting operations. The cutting accuracy cannot meet the high safety requirements of the nuclear main pump, which is likely to cause the cutting surface to be uneven, affecting the assembly and service performance of subsequent components. Operators also face a high radiation risk during the cutting process. Summary of the Invention

[0003] A nuclear main pump weld cutting device, which includes a slewing mechanism, a lifting mechanism, a cutting mechanism, and a chip collection tray; among them, the chassis bracket, slewing bearing, and slewing bearing electric motor constitute the slewing mechanism; the electric cylinder and the connecting piece A constitute the lifting mechanism; the saw blade milling cutter, the connecting piece B, and the milling cutter electric motor constitute the cutting mechanism;

[0004] Among them, in the slewing mechanism, a plurality of threaded holes are opened on the outer ring of the lower part of the chassis bracket, and the threaded holes are evenly distributed at equal intervals along the circumferential direction, corresponding to the threaded holes reserved on the stator of the nuclear main pump equipment. Bolts are used to connect and fix the outer ring of the lower part of the chassis bracket to the equipment stator;

[0005] A plurality of threaded holes are opened on the inner ring of the upper part of the chassis bracket, and the threaded holes are evenly distributed at equal intervals along the circumferential direction. Corresponding threaded holes are opened on the outer ring of the slewing bearing device. Bolts are used to connect the inner ring of the upper part of the chassis bracket to the outer ring of the slewing bearing; a plurality of threaded holes are opened on the inner ring of the slewing bearing, and they are evenly distributed at equal intervals along the circumferential direction;

[0006] In the lifting mechanism, a plurality of threaded holes corresponding to the inner ring of the slewing bearing are opened at the lower end of the connecting piece A, and through bolts, it is connected to the inner ring of the slewing bearing; the upper end is threadedly connected to the electric cylinder,

[0007] In the cutting mechanism, the connecting piece B is threadedly connected to the end of the telescopic rod of the upper electric cylinder, and the connecting piece fastens the milling cutter electric motor. The milling cutter electric motor drives the saw blade milling cutter to cut the weld;

[0008] The chip collection tray is tensioned on the inner wall of the stator, and a magnet is fixed inside to attract chips.

[0009] The chassis bracket is directly fixed to the stator part at the shaft end of the rotating equipment. The outer shape of the chassis bracket is composed of two concentric rings of different sizes, divided into an upper inner ring and a lower outer ring. The outer shape of the lower outer ring is the same as that of the stator of the nuclear main pump equipment.

[0010] The slewing bearing is driven by a servo motor and rotates around the axis of the equipment rotor, driving the cutting mechanism fixed on the slewing bearing to achieve circumferential cutting of the nut weld.

[0011] The axis direction of the saw blade milling cutter is perpendicular to the weld. The outer diameter of the saw blade milling cutter is at least 5 times the nominal diameter of the nut. When the milling cutter cuts into the weld by a depth of 2 - 4 mm, the chord length of the cut-in part is greater than the length of one edge of the nut, and the weld on one edge of the nut is completely cut in one feed.

[0012] The positioning of the milling cutter only uses the rotational movement of the slewing bearing and the up and down movement of the electric cylinder.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) The weld cutting device of the present invention is directly installed on the stator of the nuclear main pump equipment, with accurate centering and small volume;

[0015] (2) Through the weld cutting device of the present invention, the rotational movement of the slewing bearing is combined with the linear movement of the electric cylinder, and the motion relationship is simple. Description of the Drawings

[0016] Figure 1 It is the external rendering of the weld cutting device of the present invention;

[0017] Figure 2 It is the cross-sectional schematic diagram of the weld cutting device of the present invention;

[0018] Wherein 1, nuclear main pump; 2, nut with weld to be cut; 3, chip collection tray; 4, stator of nuclear main pump; 5, chassis bracket; 6, slewing bearing motor; 7, motor end cover; 8, slewing bearing; 9, saw blade milling cutter nut; 10, saw blade milling cutter; 11, milling cutter motor; 12, electric cylinder; 13, connecting piece A; 14, connecting piece B.

[0019] Figure 3 It is the structural schematic diagram of the weld cutting device of the present invention;

[0020] Figure 4 It is the dimensional relationship between the outer diameter of the milling cutter of the weld cutting device of the present invention and the size of the nut to be cut;

[0021] Figure 5 It is the schematic diagram of the inner and outer rings of the chassis bracket of the weld cutting device of the present invention.

[0022] Figure 6 Schematic diagram of connecting piece B of the weld cutting device of the present invention.

[0023] Figure 7 Schematic diagram of connecting piece A of the weld cutting device of the present invention. Specific embodiments

[0024] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0025] As Figures 1 to 4 shown, the weld cutting device includes: 1. Nuclear main pump; 2. Nut of the weld to be cut; 3. Chip collection tray; 4. Nuclear main pump stator; 5. Chassis bracket; 6. Slewing bearing motor; 7. Motor end cover; 8. Slewing bearing; 9. Saw blade milling cutter nut; 10. Saw blade milling cutter; 11. Milling cutter motor; 12. Electric cylinder; 13. Connecting piece A; 14. Connecting piece B.

[0026] The present invention is a weld cutting device, which includes a slewing mechanism, a lifting mechanism, a cutting mechanism, and a chip collection tray. Among them, the chassis bracket, slewing bearing, and slewing bearing motor constitute the slewing mechanism; the electric cylinder and connecting piece A constitute the lifting mechanism; the saw blade milling cutter, connecting piece B, and milling cutter motor constitute the cutting mechanism; the chip collection tray is responsible for chip collection.

[0027] Among them, the lower part of the chassis bracket is directly fixedly connected to the rotor equipment, playing a role of positioning and supporting. The upper part of the chassis bracket is fixedly connected to the outer ring of the slewing bearing. The slewing bearing is fixedly connected to the electric cylinder through connecting piece A. The electric cylinder rotates around the axis with the inner ring of the slewing bearing to cut welds at different positions. The lower end of the electric cylinder is fixedly provided with a milling cutter motor and a milling cutter through connecting piece B. The milling cutter motor and the milling cutter move up and down with the telescopic rod of the electric cylinder. The milling cutter motor drives the saw blade milling cutter to cut from above the nut weld.

[0028] Furthermore, the chassis bracket is in a shape similar to a flange, composed of two stacked rings, divided into an inner ring and an outer ring. There are threaded holes on the outer ring corresponding to the threaded holes of the nuclear main pump equipment stator for threaded connection. There are threaded holes on the inner ring corresponding to the threaded holes of the outer ring of the slewing bearing for threaded connection.

[0029] Furthermore, the slewing bearing has two rings sleeved together. The outer ring of the slewing bearing is fixedly connected to the low chassis bracket through bolts. The inner ring is fixedly connected to the electric cylinder through connecting piece A. The electric cylinder can rotate with the inner ring of the slewing bearing, thereby changing the machining position of the milling cutter. The inner and outer rings respectively have 1,600 threaded holes, the outer diameter is 986 millimeters, the inner diameter is 800 millimeters, and the total height is 135 millimeters.

[0030] Furthermore, the electric cylinder is mainly composed of a servo motor and a lead screw, which can convert the rotary motion of the servo motor into a linear motion. At the same time, the optimal advantages of the servo motor, such as precise rotational speed control and precise torque control, are converted into precise speed control and position control. A milling cutter motor is fixedly installed at the end of the electric cylinder.

[0031] Furthermore, the milling cutter motor is fixedly installed at the end of the electric cylinder. The up and down movement of the end of the electric cylinder drives the up and down movement of the milling cutter motor, thereby realizing feed. The working voltage of the milling cutter motor is 380V, the power is 1.1kW, the rotational speed is 1400 revolutions, and it is Y-connected.

[0032] Furthermore, the milling cutter uses a saw blade milling cutter with an outer diameter of 200 mm and an inner diameter of 30 mm. It is made of high-hardness materials.

[0033] Under the chassis bracket, it is bolted to the stator of the nuclear main pump equipment. Above the chassis bracket, it is connected to the slewing bearing by 16 M20 bolts. The slewing bearing is fixedly connected to the electric cylinder. The electric cylinder is connected to the milling cutter motor, and the milling cutter motor drives the saw blade milling cutter to cut the weld.

[0034] Specifically, when the chassis bracket is connected to the stator of the lower equipment, a layer of non-metallic material needs to be added as a gasket for protection. To prevent damage to the equipment stator due to improper operation and excessive motor power.

[0035] Specifically, a certain number and size of magnets are fixedly placed inside the chip collection device for collecting chips. The shape of the chip collection device is similar to a disc, or other shapes suitable for the operating environment. The material of the chip collection device is selected as plastic or other materials with a certain elasticity, so that it can be tensioned around the nut.

[0036] Specifically, the outer diameter of the saw blade milling cutter should be large enough so that when cutting into the weld, it can ensure the chord length of the cut and can cut all the welds on one edge of the nut at one time, without the need to continue feeding along the direction of the edge, as Figure 4 shown.

[0037] Inside the equipment stator, there is only the up and down movement of the electric cylinder and the cutting movement of the saw blade milling cutter, which is convenient for working in a narrow space.

[0038] The positioning of the milling cutter only uses the rotational movement of the slewing bearing and the up and down movement of the electric cylinder, with a simple structure and convenient control of positioning.

Claims

1. A nuclear main pump weld cutting device, which includes a slewing mechanism, a lifting mechanism, a cutting mechanism, and a chip collection tray. Among them, the chassis bracket, slewing bearing, and slewing bearing electric motor constitute the slewing mechanism; the electric cylinder and connecting piece A constitute the lifting mechanism; the saw blade milling cutter, connecting piece B, and milling cutter electric motor constitute the cutting mechanism. Among them, In the slewing mechanism, a plurality of threaded holes are opened on the outer ring of the lower part of the chassis bracket. The threaded holes are evenly distributed at equal intervals along the circumferential direction and correspond to the threaded holes reserved on the stator of the nuclear main pump equipment. Bolts are used to connect and fix the outer ring of the lower part of the chassis bracket to the equipment stator. A plurality of threaded holes are opened on the inner ring of the upper part of the chassis bracket. The threaded holes are evenly distributed at equal intervals along the circumferential direction. Corresponding threaded holes are opened on the outer ring of the slewing bearing device. Bolts are used to connect the inner ring of the upper part of the chassis bracket to the outer ring of the slewing bearing. A plurality of threaded holes are opened on the inner ring of the slewing bearing and are evenly distributed at equal intervals along the circumferential direction. In the lifting mechanism, a plurality of threaded holes corresponding to the inner ring of the slewing bearing are opened at the lower end of the connecting piece A. Through bolts, it is connected to the inner ring of the slewing bearing. The upper end is threadedly connected to the electric cylinder. In the cutting mechanism, the connecting piece B is threadedly connected to the end of the telescopic rod of the upper electric cylinder. The connecting piece fastens the milling cutter electric motor, and the milling cutter electric motor drives the saw blade milling cutter to cut the weld. The chip collection tray is tensioned on the inner wall of the stator, and a magnet is fixed inside to attract chips.

2. The weld cutting device according to claim 1, wherein, The chassis bracket is directly fixed to the stator part at the shaft end of the rotating equipment. The outer shape of the chassis bracket is composed of two superimposed rings of different sizes, divided into an upper inner ring and a lower outer ring. The outer shape of the lower outer ring is the same as the shape of the stator of the nuclear main pump equipment.

3. A weld cutting device according to claim 1, characterized in that, The slewing bearing is driven by a servo motor to rotate around the axis of the equipment rotor, driving the cutting mechanism fixed on the slewing bearing to realize circumferential cutting of the nut weld.

4. A weld cutting device according to claim 1, characterized in that, The axis direction of the saw blade milling cutter is perpendicular to the weld. The outer diameter size of the saw blade milling cutter is at least 5 times the nominal diameter of the nut. When the milling cutter cuts into the weld by a depth of 2 - 4 mm, the chord length of the cut-in is greater than the length of one edge of the nut, and the weld on one edge of the nut is completely cut in one feed.

5. A weld cutting device according to claim 1, characterized in that, The positioning of the milling cutter only uses the rotational movement of the slewing bearing and the up and down movement of the electric cylinder.

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