JPH0129345Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a pipe gripping device used for connecting a pipe support device such as a snubber to a pipe.

[Conventional technology]

Pipes used in nuclear power plants, chemical plants, etc. are supported by fixed structures via various support devices such as stoppers, struts, and hangers. Conventionally, when connecting these piping support devices and piping, a pair of clamp fittings formed into a substantially U-shaped curve from a metal plate are positioned opposite each other, and the opposing ends of these clamp fittings are tightened with bolts. Accordingly, the piping is held between the clamp fittings, and one end of the clamp fittings is connected to the support device.

[Problem that the invention attempts to solve]

Therefore, in large-diameter, heavy-load piping, the weight of the piping support becomes extremely large as the clamp fittings become larger, giving excessive concentrated weight to the piping system. Moreover, since the clamp fitting has a high bending rigidity, it is difficult to make the inner surface of the clamp fitting evenly adhere to the outer circumferential surface of the piping over the entire circumference due to dimensional tolerances when bending it. Ta. As a result, a portion of the clamp fitting may come into contact with the pipe unevenly, causing local stress concentration or causing structural looseness.

If the pipe support device only has the function of supporting the weight of the pipe, insufficient tightening may not cause any practical problems, but if the pipe support device is not tightened enough, it may not cause any practical problems. In support devices used for shaking or earthquake resistance,
If the tightening is insufficient, the function of the support device cannot be fully demonstrated. Additionally, during plant operation, piping may deviate from its planned position due to thermal expansion, etc. In this case, if the tightening is insufficient, the piping may slip in rotation (rotational misalignment) or become misaligned in the pipe axis direction. may occur and impair the function of the support device.

Therefore, the purpose of the present invention is to obtain sufficient clamping force for piping, have high binding reliability, and
Moreover, the object is to obtain a piping gripping device which has a simple structure and can be constructed lightweight.

[Means for solving problems]

The piping gripping device of the present invention has a yoke having an arcuate support surface shaped along the outer circumferential surface of the piping, and a length capable of being wrapped around the outer circumferential surface of the piping at least over its entire circumference. It also includes a wire rope whose both ends are supported by the yoke, and a tension adjustment mechanism provided between at least one end of the wire rope and the yoke. This tension adjustment mechanism applies tension to the wire rope to tightly wrap the wire rope around the entire circumference of the pipe, and also presses the pipe against the arcuate support surface of the yoke.

[Effect]

Wire rope has low bending rigidity and can exhibit high rigidity in the length direction, so when the wire rope that has been wound around the outside of the pipe at least one turn is tightly tightened using the tension adjustment mechanism, the wire rope will tighten around the outside of the pipe. Fits extremely well all around. For this reason, the entire circumference of the pipe is tightened with an even force without uneven contact with the pipe, and the pipe is firmly fixed to the yoke via this wire rope. In this case, if an appropriate initial tension (preload) is given to the tension adjustment mechanism, it can be used with a desired spring constant.

〔Example〕

Hereinafter, the gripping device A according to an embodiment of the present invention will be described as follows.
This will be explained with reference to the figures and FIG. A metal yoke 1 is connected to a piping support device S such as a snubber via a pin 2 provided at its upper end. An arcuate support surface 3 having a curvature corresponding to the outer peripheral surface of the pipe 4 to be supported is formed at the lower end of the yoke 1.
A part of the pipe 4 is circumscribed by this support surface 3 . Tension adjustment mechanisms 5 are provided on both sides of the yoke 1, respectively.

In the illustrated example, the tension adjustment mechanism 5 is connected to the yoke 1.
It is provided with a bolt 6 passing through it and a nut 7 screwed into one end of the bolt 6. 8 is a locking nut. However, an end clamp using parts other than the bolt 6 and nuts 7 and 8 may be adopted.
The other end of each bolt 6 is connected to the end of a wire rope 10 via, for example, a single lock joint 9. The wire rope 10 is wound approximately 1.5 times around the outer peripheral surface of the pipe 4.

According to the above configuration, at least one nut 7
By rotating the wire rope 10, a desired tension can be applied to the wire rope 10, and the pipe 4 can be tightened with the desired strength by the yoke 1 and the wire rope 10. By utilizing the elasticity of the wire rope 10 and adjusting its initial tension (preload), not only can it be used with an arbitrary spring constant, but its rigidity can be brought as close to infinity as possible.

That is, as shown in FIG. 6, the gripping device A when a preload P' is applied to the wire rope 10.
The spring characteristic of is represented by a dashed line, and the spring constant is
It is KR. The equivalent spring characteristic that leads to the rated load P of the support device (snut bar) S when the preload P' is applied in this way is represented by a solid line in the figure, and the spring constant is KRE. The spring characteristics when the preload P' is zero are represented by a two-dot chain line (the spring constant is KR).

Therefore, Δ'=(P-P')/KR KRE=P/Δ'=P・KR/(P-P') This means that the preload P' must be equal to the rated load P of the support device S. This means that the theoretical equivalent spring constant is infinite. If this is expressed in a graph, it will look like Figure 7.

When the pipe 4 is connected to the support device S via the gripping device A having the above configuration, the overall rigidity K must be considered as a series combination of the rigidity Ks of the support device S and the rigidity Ka of the gripping device A.

Therefore, the overall stiffness is expressed as K=[(1/Ks)+(1/Ka)] ^-1 . In other words, if Ks=Ka,
As a result, the overall stiffness K is only half of the rated stiffness of the support device S.

However, according to the gripping device A of this embodiment, as described above, by increasing the tension of the wire rope 10, it is possible to make the rigidity as close to infinity as possible. There will be no loss of functionality,
The original function of the support device s can be fully demonstrated.

In addition, since the wire rope 10 has low bending rigidity, it easily conforms to the outer periphery of the pipe 4 and has excellent adhesion, and can effectively prevent relative rotational slip and axial displacement of the pipe 4. In addition, since the wire rope 10 exhibits elasticity, even if it is tightly tightened, the tightening force will not decrease due to creep, etc. Moreover, since it is wound approximately 1.5 times, it can withstand eccentric loads, etc. Delivers great braking power.

Note that the present invention is not limited to the above embodiments. For example, the present invention is also applicable when the pipe 4 is covered with a heat insulating layer or the like. Further, as illustrated in FIGS. 3 and 4, a plurality of wire ropes 10 (in the case of two wire ropes in the figure) may be connected to one yoke 1. The restraining force against axial displacement can be improved. Further, if necessary, the number of turns of the wire rope 10 around the pipe 4 may be increased to two or more. By doing so, it is possible to further improve the restraining force against rotational displacement of the pipe 4, and further reduce the local stress of the pipe 4 due to the tightening force.

In any of the above cases, the tension adjustment mechanism 5 is provided only at one end of the wire rope 10, as illustrated in FIG.
1 may be connected to the yoke 1. Further, a suitable protective material such as stainless mesh may be interposed between the pipe 4 and the yoke 1 or the wire rope 10. In addition, various modifications or applications are possible within the scope of the gist of the present invention.

[Effect of idea]

According to the present invention, tension is applied to the wire rope through the tension adjustment mechanism, and the wire rope is strongly tightened around the entire circumference of the pipe, and the pipe is pressed against the arcuate support surface of the yoke. In addition to being able to fit in well with the piping, it can also generate a large frictional force between the piping and the piping, which effectively prevents rotational slippage and axial displacement of the piping, resulting in extremely high restraint reliability. Moreover, since the wire rope exhibits a certain degree of elasticity, even if the pipe is strongly tightened, a decrease in the tightening force due to creep is prevented. Therefore, when applied to vibration-proof or earthquake-proof support devices such as stoppers and struts, the functions of these support devices can be fully demonstrated. Moreover, the structure is simpler and lighter than the conventional one using a pair of metal clamp members curved and formed from a metal plate.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view of one embodiment of the present invention, Fig. 2 is a side view of the gripping device shown in Fig. 1, and Fig. 3 is a partially sectional view of another embodiment of the present invention. 4 is a side view of the gripping device shown in FIG. 3; and FIG. 5 is a front view, partially in section, of yet another embodiment of the present invention. FIG. 6 is a diagram showing the relationship between displacement and load when a preload is applied to the wire rope, and FIG. 7 is a diagram showing the relationship between preload and spring constant. A...Piping gripping device, S...Piping support device,
DESCRIPTION OF SYMBOLS 1... Yoke, 3... Arc-shaped support surface, 4... Piping, 5... Tension adjustment mechanism, 10... Wire rope.

Claims (1)

[Scope of Claim for Utility Model Registration] A pipe gripping device provided between a pipe and a pipe support device, comprising: a yoke having an arcuate support surface shaped along the outer circumferential surface of the pipe; and an outer circumference of the pipe. a wire rope having a length that can be wrapped around the surface at least over its entire circumference and having both ends supported by the yoke; and a wire provided between at least one end of the wire rope and the yoke. A grip for piping, characterized in that it is equipped with a tension adjustment mechanism that presses the piping against the arcuate support surface of the yoke while the wire rope is wrapped around the entire circumference of the piping by applying tension to the rope. Device.