Cable sealing structure of nuclear main pump shielding motor

Abstract

The invention discloses a nuclear main pump shielding motor cable sealing structure, and belongs to the technical field of nuclear pump devices. The structure comprises a wire outlet box body fixedly arranged on the nuclear pump shielding motor, a cable is led out through the wire outlet box body, the wire outlet box body is further provided with a sealing seat assembled on the outer side of the cable, the bottom of the sealing seat is located between the wire outlet box body and the cable, and a sealing ring is arranged between the upper portion of the sealing seat and the cable. A pre-tightening mechanism is arranged at the top of the sealing seat, and a locking mechanism is arranged on the outer side of the sealing seat; the design of the sealing seat, the pre-tightening mechanism and the locking mechanism is fully utilized in structural design, the sealing effect of the whole structure can be effectively achieved, the structure is simple, the sealing effect is better, sealing is achieved through the self-sealing principle of the sealing ring and the principle that the thread sleeve is pre-tightened to extrude the sealing ring, and the sealing effect is good. The sealing of the nuclear main pump shielding motor cable under the accident condition can be realized.

Description

Technical Field

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

[0002] The canned motor of the nuclear main pump is a power source for the pump used to drive the internal circulation of the coolant in the reactor coolant system, and is one of the core components in the nuclear island. In the accident condition, the environment where the canned motor of the reactor coolant pump is located is relatively harsh, with the characteristics of high temperature, high pressure and high humidity. When the cable for transmitting electric energy of the canned motor penetrates to the outside of the motor terminal box, since the cable in the terminal box is bare copper wire, it is necessary to prevent the high-temperature, high-pressure and high-humidity water vapor in the cabin where the canned motor is located from entering the inside of the terminal box, resulting in the dampness of the wiring copper plates, copper wires, etc. in the terminal box, and causing the failure of the function of the canned motor, leading to the inability of the coolant in the entire reactor to circulate, and possibly causing the entire system to lose its function. Cable sealing has become a potential source of failure for the canned motor of the nuclear main pump.

[0003] At present, most cable seals simply use a sealing ring cylindrical surface or an O-ring for cable sealing. Using this method can only ensure that the gap between the inner wall of the terminal box body outlet and the cable sheath is filled by pressing the sealing ring to achieve sealing, but it cannot guarantee the leakage problem under alternating pressure and temperature; the advantage of this structure is that the sealing ring is simple, and the disadvantage is that it does not fully consider that the cable is not a rigid constraint, the sheath is generally plastic or rubber, and the sealing ring is generally made of rubber material. Rubber will also produce different deformations at different temperatures. Under the action of alternating pressure and temperature, the pre-tightening force will become smaller and smaller, and finally leakage will occur. The cable of the reactor main pump motor has higher sealing requirements. With the relatively harsh environment where the canned motor of the reactor coolant pump is located in the accident condition, this method can no longer meet the current design requirements.

[0004] There are also a small number of cases that optimize the shape and structure of the sealing ring step by step according to the main factors of the shape change of the sealing ring. The advantage of this method is that it can effectively reduce the overall assembly difficulty, and the disadvantage is that the shaping method of the sealing ring is complex and the universality is poor, which greatly lengthens the development cycle of the sealing ring. Summary of the Invention

[0005] The object of the present invention is to provide a cable sealing structure for a canned motor of a nuclear main pump, which can effectively improve the ability and adaptability level of multi-end face effective deformation of the cable seal of the canned motor of the nuclear main pump, and enhance its universality and operability.

[0006] The technical solution adopted by the present invention is as follows: A cable sealing structure for a canned motor of a nuclear main pump, comprising an outlet box body fixedly arranged on the canned motor of the nuclear pump, the cable is led out through the outlet box body, the outlet box body is further provided with a sealing seat assembled on the outer side of the cable, the bottom of the sealing seat is located between the outlet box body and the cable, a sealing ring is arranged between the upper part of the sealing seat and the cable, a pre-tightening mechanism is arranged at the top of the sealing seat, and a locking mechanism is arranged on the outer side of the sealing seat.

[0007] Further, the pre-tightening mechanism comprises a pressing sleeve arranged on the outer side of the cable, and one end of the pressing sleeve is matched with the sealing ring.

[0008] Further, the pre-tightening mechanism further comprises a second screw sleeve arranged at the other end of the pressing sleeve.

[0009] Further, a snap ring is arranged inside the second screw sleeve, the snap ring is located on the outer side of the cable, and both ends are in a slope structure and are respectively matched with the end of the pressing sleeve and the inner end of the second screw sleeve.

[0010] Further, the locking mechanism comprises a first screw sleeve, the first screw sleeve is in threaded match with the sealing seat, a limiting platform is arranged on the pressing sleeve and is matched with the top of the first screw sleeve, and the pre-tightening of the sealing ring by the pressing sleeve is driven by the rotation of the first screw sleeve.

[0011] Further, a screw is further arranged between the first screw sleeve and the pressing sleeve for fixed connection.

[0012] Further, the sealing ring comprises a large deformation area in the middle and general deformation areas at both ends of the large deformation area.

[0013] Further, an auxiliary deformation section and a control area are further arranged in the large deformation area, and an inner arch structure is constructed through the auxiliary deformation section or the control area to strengthen the deformation contact of the sealing ring surface.

[0014] Further, in the general deformation area, it contacts the end face of the sealing seat and the pre-tightening structure in a cylindrical section manner.

[0015] Further, the cylindrical surfaces of the large deformation area and the general deformation area are connected in a flexible curved surface manner.

[0016] To sum up, due to the adoption of the above technical solutions, the beneficial effects of the present invention are: 1. The cable sealing structure of the canned motor of the nuclear main pump of the present invention makes full use of the design of the sealing seat, the pre-tightening mechanism and the locking mechanism in the structural design, can effectively achieve the sealing effect of the whole structure, has a simple structure and a better sealing effect, and realizes sealing through the self-sealing principle of the sealing ring and the principle of pre-tightening the sealing ring by the screw sleeve, and can realize the sealing of the cable of the canned motor of the nuclear main pump under accident conditions; 2. A cable sealing structure for a canned motor of a nuclear main pump according to the present invention, through further optimizing the design of the sealing ring structure, compared with the traditional sealing ring structure designs such as C-shaped and Z-shaped structures, improves the ability of the multi-end face of the seal to effectively deform and the adaptability level, enhances its versatility and operability, and further enhances the effect of the sealing ring form adapting to the rapid sealing of the cable specifications of the canned motor of the nuclear main pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described by way of examples with reference to the accompanying drawings, in which: Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a schematic external structure diagram of the present invention; Figure 3 is a schematic structural diagram of the sealing ring of the present invention.

[0018] In the figure: 1 - outlet box body, 2 - sealing seat, 3 - sealing ring, 4 - first screw sleeve, 5 - screw, 6 - pressing sleeve, 7 - second screw sleeve, 8 - snap ring, 9 - cable, 10 - large deformation area, 11 - general deformation area, 12 - auxiliary deformation section, 13 - control area. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] All features disclosed in this specification, or all steps in any method or process disclosed, except for mutually exclusive features and / or steps, can be combined in any manner.

[0020] Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features.

[0021] Embodiment 1 A cable sealing structure for a canned motor of a nuclear main pump, as Figure 1 and Figure 2 shown, includes an outlet box body 1 fixedly arranged on the canned motor of the nuclear pump, the cable is led out through the outlet box body 1, the outlet box body 1 is further provided with a sealing seat 2 assembled on the outer side of the cable, the bottom of the sealing seat 2 is located between the outlet box body 1 and the cable, a sealing ring 3 is arranged between the upper part of the sealing seat 2 and the cable, a pre-tightening mechanism is arranged at the top of the sealing seat 2, and a locking mechanism is arranged on the outer side of the sealing seat 2.

[0022] Based on the above specific structural design, a more specific design is that the pre-tightening mechanism includes a pressing sleeve 6 arranged on the outer side of the cable, and one end of the pressing sleeve 6 is matched with the sealing ring 3.

[0023] In a more specific design, the pre-tightening mechanism further includes a second screw sleeve 7 disposed at the other end of the compression sleeve 6. A clamping ring 8 is disposed on the inner side of the second screw sleeve 7, the clamping ring 8 is located on the outer side of the cable, and the two ends are sloped structures, and are matched with the end of the compression sleeve 6 and the inner end of the second screw sleeve 7, respectively.

[0024] Based on the design of the above specific structure, the locking mechanism is further designed, and 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.

[0025] More specifically, a screw 5 is provided between the first threaded sleeve 4 and the pressing sleeve 6 , and a fixed connection is achieved through the screw 5 .

[0026] 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 rotation of the compression sleeve 6, and the clamping ring 8 is pre-tightened by the second screw sleeve 7 to reduce the opening of the clamping ring 8, thereby compressing the cable 9 and preventing the sealing ability of the sealing ring 3 from being reduced due to the shaking of the cable 9.

[0027] In the above-mentioned specific structural design, the first screw sleeve 4 can be screwed in to drive the clamping sleeve 6 to move toward the sealing ring 3, so as to further pressurize the sealing ring 3, and the self-deformation structure design of the sealing ring 3 can further provide a better sealing effect. In the above-mentioned specific structural design, the 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.

[0028] 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 .

[0029] 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.

[0030] 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.

[0031] 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.

[0032] In the design of the above specific structure, the principle of sealing the cable 9 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 tightly squeeze the sealing seat 2, the compression sleeve 6 and the cable sheath, thereby achieving sealing. The cable 9 is not rigidly constrained, and the sheath is generally made of plastic or rubber, which will undergo a 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. The design of this sealing ring 3 adopts the method of super pre-tightening, indirectly increasing the multi-end face deformation of the sealing ring 3. Through the compensation function of the large deformation area 10, it not only increases the sealing contact area and compensates for the possibly reduced pre-tightening force, but also is fixed by the snap ring 8 to weaken the sealing reduction caused by the deformation brought by the movement of the cable sheath. It belongs to a multi-end face compensating sealing ring.

[0033] During operation, the sealing ring 3 in the cable sealing structure is extruded and deformed on the surface of the motor cable sheath; boundary conditions and loads are applied, and the finite element solution is carried out for the sealing ring 3; according to the deformation result of the sealing ring 3, the whole sealing ring 3 is divided into a large deformation area 10 in the middle and general deformation areas 11 at both ends; an auxiliary deformation section 12 and a control area 13 are added to the large deformation area 10, and an inner arch structure is constructed through the auxiliary deformation section 12 or the control area 13 to strengthen the deformation contact of the sealing ring surface; in the general deformation areas 11 at both ends, it contacts the end face of the sealing seat 2 and the compression sleeve 6 in a cylindrical section manner; the cylindrical surfaces of the large deformation area 10 controlled by the inner arch structure and the general deformation areas 11 are connected in a flexible curved surface manner; the open snap ring 8 is pre-tightened by the screw sleeve, improving the stability of the deformation of the sealing ring 3 and having strong adaptability.

[0034] In summary: 1. For a cable sealing structure of a nuclear main pump canned motor of the present invention, in the structural design, the design of the sealing seat, the pre-tightening mechanism and the locking mechanism is fully utilized, which can effectively achieve the sealing effect of the whole structure. The structure is simple and the sealing effect is better. Sealing can be achieved through the self-sealing principle of the sealing ring and the principle of squeezing the sealing ring by screw sleeve pre-tightening, and the sealing of the nuclear main pump canned motor cable under accident conditions can be realized; 2. For a cable sealing structure of a nuclear main pump canned motor of the present invention, through further optimized design of the sealing ring structure, compared with the traditional sealing ring structure design, such as the C-shaped, Z-shaped and other structures, the ability of the sealing multi-end face to effectively deform and the adaptability level are improved, its versatility and operability are enhanced, and further the effect of the sealing ring form adapting to the rapid sealing of the nuclear main pump canned motor cable specifications is enhanced.

[0035] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature disclosed in this specification or any new combination, as well as any new method or process step disclosed or any new combination.

Claims

1. A shielded motor cable sealing structure for a nuclear main pump, characterized in that: It includes an outlet box body fixedly arranged on the nuclear pump shielded motor, the cable is led out through the outlet box body, the outlet box body is also 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 arranged between the upper part of the sealing seat and the cable, a pre-tightening mechanism is arranged on the top of the sealing seat, and a locking mechanism is arranged on the outside of the sealing seat.

2. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 1, characterized in that: The pre-tightening mechanism comprises a compression sleeve arranged outside the cable, and one end of the compression sleeve matches the sealing ring.

3. A shielded motor cable sealing structure for a nuclear main pump as described in claim 2, characterized in that: The pre-tightening mechanism also includes a second screw sleeve arranged at the other end of the compression sleeve.

4. A shielded motor cable sealing structure for a nuclear main pump as described in claim 3, characterized in that: A clamping ring is arranged on the inner side of the second screw sleeve. The clamping ring is located on the outer side of the cable, and both ends of the clamping ring are sloped and matched with the end of the compression sleeve and the inner end of the second screw sleeve respectively.

5. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 2, characterized in that: The locking mechanism includes a first screw sleeve, which is matched with the sealing seat through threads. A limiting platform is provided on the compression sleeve and matches with the top of the first screw sleeve. The rotation of the first screw sleeve drives the compression sleeve to pre-tighten the sealing ring.

6. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 5, characterized in that: Screws are also provided between the first threaded sleeve and the compression sleeve to achieve a fixed connection.

7. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 1, characterized in that: The sealing ring comprises a large deformation zone located in the middle and general deformation zones located at both ends of the large deformation zone.

8. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 7, characterized in that: 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.

9. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 8, characterized in that: The general deformation zone contacts the sealing seat end face and the pre-tightening structure through a cylindrical section.

10. A shielded motor cable sealing structure for a nuclear main pump as claimed in claim 9, characterized in that: The cylindrical surfaces of the large deformation zone and the general deformation zone are connected by means of a flexible curved surface.

Images