A shielded motor cable sealing structure for a nuclear main pump

Abstract

The present invention discloses a cable sealing structure for a shielded motor of a nuclear main pump, which belongs to the technical field of nuclear pump devices. The structure comprises an outlet box body fixedly arranged on the shielded motor of the nuclear pump, and the cable is led out through the outlet box body. The outlet box body is further provided with a sealing seat assembled on the outside of the cable, and the bottom of the sealing seat is located between the outlet box body and the cable, a sealing ring is provided between the upper part of the sealing seat and the cable, a pre-tightening mechanism is provided on the top of the sealing seat, and a locking mechanism is provided on the outside of the sealing seat. The present invention makes full use of the design of the sealing seat, the pre-tightening mechanism and the locking mechanism in structural design, and can effectively achieve the sealing effect of the entire structure. The structure is simple and the sealing effect is better. The sealing is achieved by the self-sealing principle of the sealing ring and the principle of squeezing the sealing ring by pre-tightening the screw sleeve, so that the sealing of the shielded motor cable of the nuclear main pump can be achieved under accident conditions.

Description

Technical Field

[0001] The invention relates to a shielded motor cable sealing structure for a nuclear main pump, belonging to the technical field of nuclear pump devices. Background Art

[0002] The shielded motor of the nuclear main pump is the power source for the pump used to drive the coolant circulation in the reactor coolant system. It is one of the heart parts of the nuclear island. During accident conditions, the shielded motor for the reactor coolant pump is located in a relatively harsh environment with the characteristics of high temperature, high pressure and high humidity. When the cable used to transmit electric energy of the shielded motor passes through the outlet box to the outside of the motor outlet box, since the cable in the outlet box is a bare copper wire, it is necessary to prevent the high temperature, high pressure and high humidity water vapor in the cabin where the shielded motor is located from entering the outlet box, causing the wiring copper plate and copper wire in the outlet box to become wet, which will cause the shielded motor to fail, resulting in the inability to circulate coolant in the entire reactor, and may cause the entire system to lose its function. Cable sealing becomes a potential source of failure of the shielded motor of the nuclear main pump.

[0003] Currently, most cable seals simply use cylindrical sealing rings or O-rings. This method only ensures a seal by compressing the sealing ring to fill the gap between the inner wall of the outlet box and the cable sheath, but it cannot guarantee leakage under alternating pressure and temperature. The advantage of this structure is the simplicity of the sealing ring. However, the disadvantage is that it does not fully consider that the cable is not a rigid constraint. The sheath is generally made of plastic or rubber, and the sealing ring is generally made of rubber. Rubber will also deform differently at different temperatures. Under the influence of alternating pressure and temperature, the preload will gradually decrease, eventually leading to leakage. The reactor main pump motor cable has higher sealing requirements. Given the harsh environment of the shielded motor used in the reactor coolant pump during accident conditions, this method no longer meets current design requirements.

[0004] There are also a few methods that optimize the shape and structure of the sealing ring step by step based on the main factors of the sealing ring's shape change. The advantage of this method is that it can effectively reduce the difficulty of overall assembly. The disadvantage is that the sealing ring's modeling method is complex and has poor versatility, which greatly prolongs the development cycle of the sealing ring. Summary of the Invention

[0005] The object of the present invention is to provide a nuclear main pump shielded motor cable sealing structure to address the above-mentioned problems, which can effectively improve the ability and adaptability of the nuclear main pump shielded motor cable sealing to effectively deform multiple end faces and enhance its versatility and operability.

[0006] The technical solution adopted in the present invention is as follows:

[0007] A cable sealing structure for a shielded motor of a nuclear main pump includes a terminal box fixedly arranged on the shielded motor of the nuclear pump, through which the cable is led out. The terminal box is also provided with a sealing seat assembled on the outside of the cable, the bottom of the sealing seat is located between the terminal box and the cable, a sealing ring is provided between the upper part of the sealing seat and the cable, a pre-tightening mechanism is provided on the top of the sealing seat, and a locking mechanism is provided on the outside of the sealing seat.

[0008] Furthermore, the pre-tightening mechanism includes a compression sleeve arranged on the outside of the cable, and one end of the compression sleeve matches the sealing ring.

[0009] Furthermore, the pre-tightening mechanism also includes a second screw sleeve arranged at the other end of the compression sleeve.

[0010] Furthermore, a clamping ring is provided on the inner side of the second screw sleeve. The clamping ring is located on the outer side of the cable, and both ends are sloped and matched with the end of the compression sleeve and the inner end of the second screw sleeve respectively.

[0011] Furthermore, the locking mechanism includes a first screw sleeve, which is matched with the sealing seat through a thread. A limiting platform is provided on the compression sleeve and matches the top of the first screw sleeve. The rotation of the first screw sleeve drives the compression sleeve to pre-tighten the sealing ring.

[0012] Furthermore, screws are provided between the first threaded sleeve and the compression sleeve to achieve a fixed connection.

[0013] Furthermore, the sealing ring includes a large deformation zone located in the middle and general deformation zones located at both ends of the large deformation zone.

[0014] Furthermore, the large deformation zone is also provided with an auxiliary deformation section and a control zone, and an inner arch structure is constructed by the auxiliary deformation section or the control zone to strengthen the deformation contact of the sealing ring surface.

[0015] Furthermore, the general deformation zone contacts the sealing seat end face and the pre-tightening structure through a cylindrical cross-section.

[0016] Furthermore, the cylindrical surfaces of the large deformation zone and the general deformation zone are connected by means of a flexible curved surface.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. The shielded motor cable sealing structure of the nuclear main pump of the present invention fully utilizes the design of the sealing seat, pre-tightening mechanism and locking mechanism in the structural design, which can effectively achieve the sealing effect of the entire structure. It has a simple structure and better sealing effect. The sealing is achieved by the self-sealing principle of the sealing ring and the principle of the screw sleeve pre-tightening to squeeze the sealing ring to achieve sealing, which can realize the sealing of the shielded motor cable of the nuclear main pump under accident conditions.

[0019] 2. The nuclear main pump shielded motor cable sealing structure of the present invention further optimizes the design of the sealing ring structure. Compared with the traditional sealing ring structure design, such as the C-shaped and Z-shaped structure design, it improves the ability and adaptability of the sealing multi-end faces to effective deformation, enhances its versatility and operability, and further enhances the effect of the sealing ring shape to adapt to the specifications of the nuclear main pump shielded motor cable for rapid sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 It is a schematic diagram of the appearance structure of the present invention;

[0023] Figure 3 It is a structural schematic diagram of the sealing ring of the present invention.

[0024] Markings in the figure: 1-outlet box body, 2-sealing seat, 3-sealing ring, 4-first screw sleeve, 5-screw, 6-compression sleeve, 7-second screw sleeve, 8-clamping ring, 9-cable, 10-large deformation area, 11-general deformation area, 12-auxiliary deformation section, 13-control area. DETAILED DESCRIPTION

[0025] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0026] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0027] Example 1

[0028] A shielded motor cable sealing structure for a nuclear main pump, such as Figure 1 and Figure 2 As shown, it includes an outlet box body 1 fixedly arranged on the nuclear pump shielded motor, and the cable is led out through the outlet box body 1. The outlet box body 1 is also provided with a sealing seat 2 assembled on the outside of the cable. The bottom of the sealing seat 2 is located between the outlet box body 1 and the cable, and a sealing ring 3 is provided between the upper part of the sealing seat 2 and the cable. The top of the sealing seat 2 is provided with a pre-tightening mechanism, and a locking mechanism is provided on the outside of the sealing seat 2.

[0029] Based on the above specific structural design, in a more specific design, the pre-tightening mechanism includes a compression sleeve 6 arranged on the outside of the cable, and one end of the compression sleeve 6 matches the sealing ring 3.

[0030] In a more specific design, the pre-tightening mechanism further includes a second screw sleeve 7 provided at the other end of the compression sleeve 6. A snap ring 8 is provided on the inner side of the second screw sleeve 7. The snap ring 8 is located on the outer side of the cable, and its two ends are sloped and match the end of the compression sleeve 6 and the inner end of the second screw sleeve 7, respectively.

[0031] Based on the design of the above-mentioned specific structure, the locking mechanism is further designed. The locking mechanism includes a first screw sleeve 4, which is matched with the sealing seat 2 through a thread. A limiting platform is provided on the clamping sleeve 6, and is matched with the top of the first screw sleeve 4. The rotation of the first screw sleeve 4 drives the clamping sleeve 6 to pre-tighten the sealing ring 3.

[0032] More specifically, a screw 5 is provided between the first threaded sleeve 4 and the compression sleeve 6 , and a fixed connection is achieved through the screw 5 .

[0033] The terminal box body 1 is fixed on the shielded motor, the sealing seat 2 is fixed on the terminal box body 1, the sealing ring 3 drives the compression sleeve 6 to be fixed in the sealing seat 2 through the first screw sleeve 4, the set screw 5 prevents the compression sleeve 6 from rotating, and the clamping ring 8 is pre-tightened by the second screw sleeve 7 so that the opening of the clamping ring 8 is reduced, and the cable 9 is compressed, thereby avoiding the reduction of the sealing ability of the sealing ring 3 caused by the shaking of the cable 9.

[0034] In the above-mentioned specific structural design, the first screw sleeve 4 can be screwed in to drive the compression sleeve 6 to move toward the sealing ring 3, thereby further pressurizing the sealing ring 3, and further providing a better sealing effect through the self-deformation structure design of the sealing ring 3. In the above-mentioned specific structural design, its structural design is simple, the operation is simple, and the applicable environment is wider. The sealing ring 3 is always kept in a relatively sealed environment, which is more conducive to the application in harsh environments such as nuclear pumps.

[0035] According to the above specific structure, the sealing ring 3 is specifically designed. The sealing ring 3 includes a large deformation zone 10 located in the middle and general deformation zones 11 located at both ends of the large deformation zone 10 .

[0036] More specifically, the large deformation zone 10 is further provided with an auxiliary deformation section 12 and a control zone 13 , and an inner arch structure is constructed by the auxiliary deformation section 12 or the control zone 13 to strengthen the deformation contact of the sealing ring surface.

[0037] Furthermore, the general deformation zone 11 contacts the end surface of the sealing seat 2 and the pre-tightening mechanism through a cylindrical cross-section.

[0038] Based on the above specific design, the cylindrical surfaces of the large deformation zone 10 and the general deformation zone 11 are connected by means of flexible curved surfaces.

[0039] In the design of the above-mentioned specific structure, the principle of cable 9 sealing is to pre-tighten the compression sleeve 6 by tightening the screw sleeve to squeeze the sealing ring 3, so that the end faces of the sealing ring 3 are squeezed tightly against the sealing seat 2, the compression sleeve 6 and the cable sheath, thereby achieving sealing. The cable 9 is not a rigid constraint. The sheath is generally made of plastic or rubber, which will undergo certain deformation under the repeated action of pressure and high and low temperatures. The sealing ring 3 is generally also made of rubber material and will also deform under different temperatures and pressures, which will affect the pre-tightening force between the sealing ring 3 and the cable sheath. The pre-tightening force will become smaller and smaller, and eventually lead to leakage. This sealing ring 3 design adopts an over-pre-tightening method, which indirectly increases the multi-end face deformation of the sealing ring 3. Through the compensation function of the large deformation zone 10, it not only increases the sealing contact area and compensates for the possible reduction in pre-tightening force, but also fixes it through the clamping ring 8 to reduce the deformation caused by the movement of the cable sheath and the resulting reduction in sealing. It is a multi-end face compensatory sealing ring.

[0040] The sealing ring 3 in the cable sealing structure is squeezed and deformed with the surface of the motor cable sheath during operation; boundary conditions and loads are applied to perform finite element solution on the sealing ring 3; according to the deformation result of the sealing ring 3, the sealing ring 3 is divided into a large deformation zone 10 in the middle and general deformation zones 11 at both ends; an auxiliary deformation section 12 and a control zone 13 are added to the large deformation zone 10, and an inner arch structure is constructed through the auxiliary deformation section 12 or the control zone 13 to strengthen the deformation contact of the sealing ring surface; in the general deformation zones 11 at both ends, contact is made with the end face of the sealing seat 2 and the compression sleeve 6 through a cylindrical section; the large deformation zone 10 controlled by the inner arch structure is connected to the cylindrical surface of the general deformation zone 11 through a flexible curved surface; the open snap ring 8 is pre-tightened by the screw sleeve, which improves the deformation stability of the sealing ring 3 and has strong adaptability.

[0041] In summary:

[0042] 1. The shielded motor cable sealing structure of the nuclear main pump of the present invention fully utilizes the design of the sealing seat, pre-tightening mechanism and locking mechanism in the structural design, which can effectively achieve the sealing effect of the entire structure. It has a simple structure and better sealing effect. The sealing is achieved by the self-sealing principle of the sealing ring and the principle of the screw sleeve pre-tightening to squeeze the sealing ring to achieve sealing, which can realize the sealing of the shielded motor cable of the nuclear main pump under accident conditions.

[0043] 2. The nuclear main pump shielded motor cable sealing structure of the present invention further optimizes the design of the sealing ring structure. Compared with the traditional sealing ring structure design, such as the C-shaped and Z-shaped structure design, it improves the ability and adaptability of the sealing multi-end faces to effective deformation, enhances its versatility and operability, and further enhances the effect of the sealing ring shape to adapt to the specifications of the nuclear main pump shielded motor cable for rapid sealing.

[0044] The present invention is not limited to the aforementioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A shielded motor cable sealing structure for a nuclear main pump, characterized by: The invention comprises an outlet box body fixedly arranged on the nuclear pump shielded motor, through which the cable is led out, the outlet box body is further provided with a sealing seat assembled on the outside of the cable, the bottom of the sealing seat is located between the outlet box body and the cable, a sealing ring is provided between the upper part of the sealing seat and the cable, a pre-tightening mechanism is provided on the top of the sealing seat, and a locking mechanism is provided on the outside of the sealing seat; The pre-tightening mechanism includes a compression sleeve arranged on the outside of the cable, and one end of the compression sleeve matches the sealing ring; The pre-tightening mechanism further includes a second screw sleeve arranged at the other end of the compression sleeve; A clamping ring is provided on the inner side of the second screw sleeve, the clamping ring is located on the outer side of the cable, and the two ends of the clamping ring are in a sloped structure and match the end of the compression sleeve and the inner end of the second screw sleeve respectively; The locking mechanism includes a first screw sleeve, the first screw sleeve and the sealing seat are matched by threads, a limiting platform is provided on the compression sleeve and matches the top of the first screw sleeve, and a screw is further provided between the first screw sleeve and the compression sleeve to fix them together; The compression sleeve is driven to move toward the sealing ring by screwing in the first screw sleeve, and the compression sleeve is driven to pre-tighten the sealing ring by rotating the first screw sleeve; the sealing ring includes a large deformation zone located in the middle and general deformation zones located at both ends of the large deformation zone; The outlet box body is fixed on the shielded motor, the sealing seat is fixed on the outlet box body, the sealing ring drives the compression sleeve to be fixed in the sealing seat through the first screw sleeve, and the clamping ring is pre-tightened by the second screw sleeve to reduce the clamping ring opening and compress the cable.

2. A shielded motor cable sealing structure for a nuclear main pump according to claim 1, characterized in that: The large deformation zone is further provided with an auxiliary deformation section and a control zone, and an inner arch structure is constructed by the auxiliary deformation section or the control zone to strengthen the deformation contact of the sealing ring surface.

3. A shielded motor cable sealing structure for a nuclear main pump according to claim 2, characterized in that: The general deformation zone contacts the sealing seat end face and the pre-tightening structure through a cylindrical cross section.

4. A shielded motor cable sealing structure for a nuclear main pump according to claim 3, characterized in that: The cylindrical surfaces of the large deformation zone and the general deformation zone are connected by means of flexible curved surfaces.

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