JPS6057061A - Sealing construction - Google Patents

Abstract

PURPOSE:To obtain simple and proper sealing construction by forming a groove over the joint face between a first member and a second member and by enabling injection of sealing agent into a passage formed so as to be connected to the groove on at least one of said members. CONSTITUTION:In such a pressure-resisting unit of the recycle pump of an atomic furnace, a stage 51 is formed annularly on the upper internal periphery of a pump casing 31, and a gasket 53 is interposed in the whole periphery as a first sealing member. A canopy seal 54 is mounted to the lower external periphery of a flange unit 49. This pump requires a long-time continuous running once started, however when the gasket 53 loses sealing function during the time, sealing agent is injected from an injection passage 63. The sealing agent is charged between the annular grooves 57, 61 and solidified by high temperature of the pump casing 31 and a casing cover 47, and leakage of cooling material from the space between joint faces 55, 59 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a seal structure, and particularly to a seal 47'7 suitable for application to a pressure-resistant part of a nuclear reactor recirculation pump.

[Background of conventional technology and its problems]

Generally, a sealing member is interposed between the joining surfaces of two or more joining members in order to prevent leakage of fluid such as gas or liquid sealed between these members.

In particular, in nuclear power plants, prevention of leakage of radioactive coolant, steam, etc. is an essential part.

FIG. 1 is a sectional view of a main part of a conventional nuclear reactor recirculation pump. An impeller 3 rotated by a motor is housed in the pump casing 1, and sucks coolant from an inlet 5 and discharges it from an outflow lower. Further, the pump casing 1 is fixed to a motor casing 11 that houses the motor by means of stud bolts 9 in the frame. Further, the upper opening of the Bonzo casing j1 is closed by a casing cup ζ-13. This casing cover 13 has a 7-run part 15 formed on its outer periphery that covers the pump casing 1.
and is fixedly supported by being clamped by the seven-take rank 11.

On the other hand, as shown in FIG. 2, a gasket 17 as a first sealing member is disposed on the inner peripheral edge forming the upper opening of the pump casing 1. This gasket 17 prevents the coolant pressurized within the pump casing 1 from leaking. In addition, part 1 of the 7 runs of the casing cover 13
5, a canopy seal 19 having an arcuate cross section is attached as a second seal member. This canopy seal 1
9 seals the lower end surface of the canopy seal 19 to the pump casing 1 when the sealing function of the gasket 17 becomes insufficient.
It adheres well to the joint surface 21 of the pump casing 1 to prevent leakage of the coolant inside the pump casing 1.

However, when welding the canopy seal 19f, since the heat capacity of the pump casing 1 is large, it takes a long time to heat the welding surface 21, and it is necessary to weld while removing several stud bolts 9 one after another. . Therefore, it takes a lot of effort and time to weld the canopy seal 19. Additionally, if the canopy seal 19 is welded, it must be removed during periodic inspection of the recirculation pump.

However, this cutting pupil may damage the welding direction 21 of the Bonzo casing, making the cutting operation extremely difficult. Furthermore, if the canopy seal 19 is removed during periodic inspection, a complicated work will occur in which a new canopy seal 19 must be attached.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a seal 41 structure that can easily and accurately prevent leakage of the internally sealed body.

[Summary of the invention]

In order to achieve the above object, the seal structure according to the present invention forms a groove that extends over the entire area of the joint surface between the first member and the second part, and Alternatively, a passage communicating with the groove is formed in at least one of the second members, and a sealing material can be injected into the groove from this passage, and the injection of the sealing material is carried out between the first member and the first member. This is done when the sealing performance of the joint surfaces between two members is insufficient, and the groove is thereby filled with a sealing material.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of a main part of a nuclear reactor recirculation pump when an embodiment of the seal structure according to the present invention is applied to the pressure-resistant part of the pump.

A pump chamber 31 is formed in a pump casing 31 serving as a first member, and an inlet port and an outlet port 37 are opened in this pump chamber 33 . This Bonno'' casing 31 is
It is fixed to the lower end of a motor casing 39 that houses the motor by a stand and bolt 41.

Further, an impeller 43 is arranged inside the pump chamber,
This impeller 43 is rotationally driven by a motor via a rotating shaft 45. As the impeller 43 rotates, the core coolant is sucked in from the inlet and is pressurized to the outlet 3.
7 is discharged from the upper part of the pump casing 31 and the motor casing 3
At the bottom of 9, a casing cover 47 as a second member is provided.
will be placed. This casing bracket 47 has a 7-rank part 49 formed on its outer periphery, and this flange part 49 is held between the pump casing 31 and the motor casing 39 and is firmly supported by being pressed by the stand bolt 41. be done. The cover casing 47 closes the upper part of the ponzo chamber.

Further, as shown in FIG. 4, a step portion 51 is formed in an annular shape at the upper inner peripheral edge of the pump casing 31 that forms the upper opening of the pump chamber 33. As shown in FIG. A gasket 53 as a first sealing member is inserted over the entire circumference of this stepped portion 51,
This prevents the coolant inside the pump chamber 33 from leaking. Furthermore, a canopy seal 54 is attached to the lower outer periphery of the 7-rank portion 49 along its entire periphery. The canopy seal 54 has an arcuate cross section, and its upper end surface is fixed to the flange portion 49 and its lower end surface can be welded to the joint surface 55 of the two-pump casing 31.

An annular groove 57 is formed in the joint surface 55 at an intermediate position between the gasket 53 and the canopy seal. Furthermore, an annular groove 61 is carved in the abutment surface 59 of the flange portion 49 that abuts the joint surface 55 at a position facing the annular groove 57 .

These annular grooves 61 and annular? ? % 55 have almost the same shape, and are formed in a circular manner between the contact surfaces and over the entire area of 59. Furthermore, an injection passage 63 is bored in the seven-langue portion 49 from the outer peripheral wall of the flange portion 49 toward the annular groove 61 . The injection passage 63 has a cylindrical shape and is formed along the outer circumferential wall of the reed and flange portion 49 at one or more locations. From this injection passage 63, as a second sealing member,
A sealing material made of a heat-set synthetic material such as permanite is injected and filled into the annular groove 57°61.

Next, the effect will be explained.

The in-furnace coolant is guided into the inlet okara pump chamber, pressurized by the rotation of the impeller 430, and discharged from the outlet 37. On the other hand, the coolant pressurized within the pump chamber 33 is
The pump casing 3 is sealed by a gasket 53.
1 and the joint surface 55 of the casing cover 47, leakage to the outside is prevented.

By the way, once the reactor recirculation pump is started, approximately 1
Although it is necessary to continue operation for a long period of 20 years, there is a risk that the gasket 53 may lose its sealing function due to aging or the like. In such a case, sealant is injected from the injection passage 63. The sealing material is filled between the annular shoulders 57 + 61 from the injection passage 63 and solidified by the high temperature of the pump casing 31 and the casing cover 47 .

This prevents the activated coolant from leaking from both junctions ifn groups 59.

Injecting the above sealing material is a very simple operation, so the high temperature standby state (hot standby state)
It is possible to quickly and accurately prevent coolant leakage while maintaining the reactor at a high temperature but not supplying main steam to the turbine.

Also, during regular inspection of the recirculation pump, check the pump casing 3.
1 and the casing cover 47 are cooled, or if they are not cooled, the sealing material can be easily removed by cooling. Furthermore, the FC pump casing 31 and the like will not be damaged during inspection. Therefore, the disassembly work of the recirculation pump during periodic inspection can be made extremely easy, and the health of the recirculation pump can be maintained.

Furthermore, if the leakage prevention of the coolant is insufficient even after filling the seal, the lower end surface of the canopy seal 54 is welded to the joint surface 55 of the +5 pump casing 31. Will this prevent leakage of radioactive coolant? ia, and there is no possibility of workers being exposed to radiation.

In the above embodiments, the injection passage 63 is cylindrical in shape, but as shown in Fig. ,
Further, as shown in FIG. 6, an injection passage 67 having a continuous shape of many stepped portions may be used.

Further, the injection passage may have a trapezoidal shape or a rectangular cylinder shape. In addition, although the above injection passages are all linear, they are not limited to this case; they may be bent into an L-shape, or may be curved into an arc. In the above embodiment and each modification, the injection passage is provided only in the flange portion 49, but it may be formed only in the pump casing 31 or in both. Similarly, the annular shape 657.61 may also be formed on either the flange portion 49 or the pump casing 31.

Furthermore, in the above embodiments and various modifications, the seal structure according to the present invention was explained only in the case where it was applied to the pressure-resistant part of the Atomic Ichiko circulation pump, but the seal structure according to the present invention was explained only when applied to the pressure-resistant part of the Atomic Ichiko circulation pump. It may be applied to a seal structure or a seal structure of a split casing such as a turbine casing. Furthermore, depending on the selection of the sealing material to be injected, it is possible to overuse it in the sealing structure between the rotating shaft and the casing.

〔Effect of the invention〕

According to the seal structure according to the present invention, a groove that circulates over the entire area of the joint surface is formed in the joint surface of the first member and the second member, and a passage communicating with this groove is formed in the joint surface of the first member and the second member. Since the sealing material is formed in at least one of the first and second members and the sealing material is injected into the groove from this passage, leakage of the fluid sealed in the space surrounded by the first and second members is prevented. This has the effect of being able to be easily and accurately prevented.

[Brief explanation of drawings]

Figure 1 is a 1υ side view of the main parts of a conventional nuclear reactor recirculation pump.
FIG. 2 is an enlarged cross-sectional view of part A in FIG. 1, and FIG. 3 is a schematic diagram of a reactor recirculation pump when an embodiment of the seal structure according to the present invention is applied to the pressure-resistant part of the pump. Partial sectional view,
FIG. 4 is an enlarged cross-sectional view of part 8 of FIG. 3, and FIGS. 5 and 6 are cross-sectional views showing modified examples of the injection passage in the same embodiment. 31... Po/zo casing, 47... Casing cover, 55, 59... Joint surface, 57, 61...
Annular groove, 63... inflow passage. Applicant's agent Shizuoka Hatano Figure 1 Figure 2 Figure 3 14F1 Figure 4 515957. 1 “1 Figure 5 q Figure 6 q 7

Claims (1)

[Claims] 1. A groove is formed in the joint surface of the first member and the second member over the entire joint surface, and at least one of the first member or the second member is provided with a groove in the groove. Forming a communicating passage,
A seal structure characterized in that a sealing material can be injected into the groove from this passage. The seal structure according to claim 1, wherein the 2° groove is formed in at least one of the first member and the second member. 3. The first member is the pump casing of the reactor recirculation pump, and the second member is this I? The seal structure according to claim 1 or 2, which is a casing cover that closes a pump cushioning. 4. The sealing structure according to any one of claims 1 to 3, wherein the sealing material is made of a material having thermal hardening performance.