JPS6041272B2 - Safety valve reaction force receiving device - Google Patents

Description

[Detailed Description of the Invention] Piping in power plants, etc. is subject to intense reaction force when the attached safety valve blows out, but the present invention provides a reaction force receiving device that prevents the piping from being damaged by this. It is related to
This is particularly important in nuclear power plants.

Under normal conditions, piping undergoes slow displacement due to temperature changes.
The Honbishi counterfeit follows this pattern without difficulty, and operates properly only against the blowout reaction force. Examples will be described with reference to the drawings.

The main case 1 has a large diameter cylinder part lb and a small diameter joint part lc connected and integrated on both sides of a central partition la, and a lid ld and a pull fitting Ie are fixed to the outside of the large cylinder part. The outer end of the diaphragm is rounded. The sub case 2 is inserted into and out of the small diameter cylindrical portion lc, a ball nut 2a is attached near the inner end, and a pull fitting 2b is fixed to the outer end. Threaded rod 3
consists of a straight portion 3a and a threaded portion 3b, and both ends of the straight portion are connected to a large diameter cylindrical portion lb via direct rotation type rolling bearings B1 and B2.
It is slidably supported within a certain range on the lid ld and central partition wall la, and is provided with a collar 3c near the outer end of the straight part. As shown in FIG. 2, the rotary direct-acting rolling bearings B1 and B2 each have the following characteristics:
A cage holding steel balls is incorporated inside the outer ring, and the straight threaded portion 3a is inserted into this cage, and the threaded rod and the cage are rotatable relative to the outer ring and are movable in the axial direction. It is. The threaded portion 3b is screwed into the ball nut 2a. The disc-shaped witness 4 is inserted into the straight part 3a with iron, and is fixed to the straight part at a position where it contacts the collar 3c. Spring 5
is inserted between the weight 4 and the central partition wall la. A thrust bearing B3 is mounted on the inner surface of the lid ld, and the weight 4 is pressed by a spring 5 and always comes into contact with the bearing B3. The central partition wall la has a bearing B3 and a thrust bearing B located opposite the bearing B3.
4 is attached so that when the weight 4 rotates, the spring 5 rotates together without any force. Weight 4 and center bulkhead l
As shown in FIG. 3, annular claw surfaces 4a and lf of the same shape are provided on the outer edge of the surface facing the center partition wall so that they engage with each other when the weight 4 moves toward the center partition. are separated by spring 5. A friction surface may be used instead of the annular claw surface. The present invention is constructed as described above, and as shown in FIG. 4, the vicinity of the attachment point of the safety valve S is selected, and one of the two handle fittings of the main body is connected to the structure, and the other is connected to the piping P.

In the figure, it is assumed that the safety valve S blows air upward and the pipe receives a reaction force downward. That is, the main case and the sub case are subjected to a force in the direction of separation from the blowout. FIG. 1 shows a case where the safety valve is not blown out and the pipe system is in a normal state.

When both cases 1 and 2 are subjected to forces of approach and separation due to displacement of the pipe system due to temperature changes, etc., the movement is slow, so even if the screw thread rotates, the weight only rotates with the bearing B3. Since the annular claw surfaces 4a and lf remain separated, the above movement is not restricted. On the other hand, if both cases 1 and 2 receive a sudden force in the direction of separation due to the safety valve blowing out,
The weight presses the spring 5 and moves slightly to the right while rotating together with the threaded rod, and the annular claw surfaces 4a, lf engage the saddles and lock the piping. A similar effect occurs on friction surfaces. When the blowing is finished, the lock is released by the action of the spring 5. The present invention can produce different embodiments based on the same idea. Fig. 5 shows an example of this, in which a weight 4 is rotatably inserted into a straight part 3a, one side of which is supported by a collar 3c, and the other side is raised vertically with a nut 6 via an inserted disc spring 7. It is something. Due to the strong pressure from the disc spring, the weight becomes stuck to the screw line and acts on the machine as described above, but if an excessive reaction force exceeding the set value is applied, that force will be due to the friction caused by the pressure of the disc spring. This overcomes the force and rotates the locked weight, protecting the device from destruction and rapid heat transfer that occurs during operation. Conventionally, as a reaction force receiving hawk,
A special hydraulic vibration isolator was used, but as long as it is hydraulic, oil leaks and oil quality deterioration are inevitable, and it cannot be used in nuclear power plants that are designed to be maintenance-free.

In contrast, in the present invention, everything is mechanically constructed, so there is no risk of performance changes over time. It is possible to lock piping that receives reaction force, and also has a vibration damping effect. The above are the features of the present invention.

[Brief explanation of drawings]

Fig. 1 is a cutaway front view of the present invention, Fig. 2 is a rotating direct type bearing, Fig. 3 is a plan view of the annular claw surface, Fig. 4 is an explanatory diagram of the use state of the present invention, and Fig. 5 is another It is a partial front view of an Example. 1...Main case, la...Central bulkhead,
lb...Large diameter cylinder part, lc...Small diameter cylinder part, l
d...lid, le...handle fitting, lf...
... Annular claw surface, 2 ... Sub-case, 2a ... Ball nut, 2b ... Pull fitting, 3 ... Threaded rod,
3a...Scaling part, 3b...Screw part, 3
c... maxim, 4... weight, 5... spring, 6... nut, 7... disc spring, B1, B2... rotary direct bearing, B3, B4... thrust bearing , P...
・Pipe system, S...Safety valve. Figure 2 Figure 'Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A main case which is formed by integrally connecting a large diameter cylindrical part and a small diameter cylindrical part via a central partition, and has a pull fitting at the outer end of the large diameter cylindrical part and an open outer end of the small diameter part; It is inserted into the small diameter cylindrical part from the open end so as to be able to come in and out, and is equipped with a ball nut near the inner end and other pull fittings at the outer end, and a threaded part and a straight part. a threaded rod that is slidably supported in the large-diameter cylindrical portion within a small length range and is threadedly engaged with the ball nut at a threaded portion; and a weight that is fixed to the straight portion of the threaded rod;
It consists of a spring inserted between the facing surfaces of the weight and the main case central partition wall, and an annular claw surface provided so as to be engageable at the outer edge of the facing surface. A safety valve reaction force receiving device in which one is connected to the structure and the other to the piping. 2. A main case consisting of a large-diameter cylindrical part and a small-diameter cylindrical part integrally connected through a central partition, with a pull fitting attached to the outer end of the large-diameter cylindrical part and an open outer end of the small-diameter cylindrical part, and a main case that is connected to the small-diameter cylindrical part. It consists of a sub-case which is inserted into and out from the open end and has a ball nut near the inner end and other pull fittings at the outer end, a threaded part and a straight part, and the straight part connects to the large diameter cylindrical part. a threaded rod that is slidably supported within a small length range and is screwed into the ball nut at a threaded portion; a weight that is rotatably attached to the straight portion of the threaded rod with frictional resistance; A disc spring inserted so as to be able to press the weight against the flange of the straight part of the threaded rod, and a spring inserted between the opposing surfaces of the weight and the central partition wall of the main case, engageable at the outer edge of the opposing surface. A reaction force receiving device for a safety valve, in which one of the two handle fittings is connected to a structure and the other to a pipe, respectively, in the vicinity of the safety valve.