JPH05240382A - Tightening device for pipe flange - Google Patents

Abstract

PURPOSE:To tighten a bolt and a nut for connecting a piping flange even under a narrow working environment with case, rapidity and high accuracy. CONSTITUTION:After temporarily fixing a bolt 12 and a nut 14 for connecting flanges 10, 10, a supporting plate 16 is secured at the tip end 20 of the bolt 12, and shape memory alloy 26 provided between the flanges 10, 10 and the supporting plate 16 is heated and elongated to push up the supporting plate 16. When tensile axial force is applied to the bolt 12, the temporarily set nut 14 is loosened, so the nut 14 is regularly tightened by the loosened amount. After that, the shape memory alloy 26 is cooled and a shrunk to remove the supporting plate 16 from piping. It is thus possible to achieve the similar good results to those obtained when the bolts 12 and nuts 14 are tightened with high accuracy to a prescribed tightening torque with a spanner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe flange tightening device, and more particularly to a pipe flange for tightening bolts and nuts by applying a predetermined axial force to the bolts when the pipes are flange-joined with the bolts and nuts. Regarding tightening device.

[0002]

2. Description of the Related Art Generally, high tightening accuracy is required so that leakage does not occur when tightening a pipe flange, particularly when tightening a flange of a high-pressure pipe for hydraulic pressure. However, this kind of work is often done in a work environment where many pipes are standing upside down, and generally a small and lightweight power tool is used, but if the work space is narrower, use a universal joint or use a spanner, etc. Tighten with a tool. In the case of a narrower space, a hammer, a chain, or the like must be used to forcibly tighten it, forcing a very difficult tightening work.

[0003]

However, when the above tool is used in a work environment with a small space, there are the following drawbacks. (1) When a power tool is used, cables or hoses are connected regardless of whether electricity, air, or hydraulic pressure is used as a power source, and the flexibility of these hoses is low.
The movement of the power tool puts a heavy burden on the operator. Furthermore, in the case of flange coupling of small diameter pipes, the space between the pipe and the bolt inserted in the flange hole is small, and the electric tool comes into contact with the pipe when tightening the bolt, so a universal joint must be used. Since the transmission torque greatly changes depending on the inclination angle of, it is impossible to tighten with accurate torque. (2) When using a hand tool, the torque wrench cannot be used when the work space is small, so tighten it with the feeling of the operator using a small wrench or use a hammer or chain if the working environment is bad. And then forcibly tighten it, there is a big problem in terms of tightening accuracy,
Often causes leakage from the flange. (3) Even if a power tool or a manual tool is used, the tightening method of the tightening torque control method has a large fluctuation range of the friction coefficient depending on the surface condition of each member even if the tightening torque is accurately controlled. However, there is a problem that the tightening accuracy is fundamentally low because the axial force of the bolt during tightening changes greatly.

Further, in order to prevent partial tightening when tightening the pipe flange, an operator moves it 3 to 4 times diagonally in accordance with the bolt position of the flange in a narrow working space and repeatedly tightens it. However, since diagonal tightening must be performed to continue the tightening work to an appropriate tightening torque, workability is very poor, and there are many drawbacks such as work efficiency, work time, and tightening torque accuracy.

The present invention has been made in view of the above circumstances, and it is possible to easily and quickly tighten bolts and nuts for flange connection of pipes even in a narrow working environment, and to perform high-precision tightening. An object is to provide a compact and lightweight pipe flange tightening device.

[0006]

In order to achieve the above-mentioned object, the present invention is to tighten a pipe flange by joining a flange of one pipe and a flange of the other pipe and tightening them with a bolt and a nut. In the device, the flange of the one pipe and the flange of the other pipe are temporarily fixed with the bolt and the nut, a support plate is fixed to the tip of the bolt, and a shape memory is provided between the flange and the support plate. An alloy is provided, and the shape memory alloy is heated to elongate the shape memory alloy to give a tensile axial force to the bolt, and in this state, the nut is finally tightened.

[0007]

According to the present invention, the bolt for connecting the flange
After temporarily fixing the nut, a support plate is fixed to the tip of the bolt, and the shape memory alloy provided between the flange and the support plate is heated to a predetermined temperature to generate a shape recovery force. By stretching and pushing up the support plate, a tensile axial force can be applied to the bolt. As a result, the temporarily fixed nut is loosened, and after the nut is fully tightened by the looseness, the shape memory alloy is cooled and contracted to remove the tightening device from the pipe.

By the above-mentioned operation, it is possible to exert the same tightening force as when the bolts and nuts for connecting the pipe flanges are accurately tightened with a predetermined tightening torque with a spanner.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a pipe flange tightening device according to the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIG. 1 and FIG. 2, first, two pipe flanges 10 and 10 to be joined are aligned, and the flanges 10 and 10 are combined.
4 hexagon bolts 12 in 4 bolt holes provided in
12 ... through the nuts 14, 14 ...

The support plate 1 pivotally supported by the opening / closing shaft 15
6 is opened, and the end portions 20 of the hexagon bolts 12, 12, ...
The support plate 16 is attached so as to sandwich the pipe 22 (upper side in FIG. 1) located on the 20 ... side, and the hexagon bolts 12 and 12 are provided in the holes formed at the four corners of the support plate 16.
Insert the tip end portions 20, 20 ... of. Further, the tension nuts 24, 24 ... Are attached to the hexagon bolts 12, 12 ,.
Hexagonal bolt 1 on the support plate 16 surface
Shape memory alloy 26 fixed at an intermediate position of 2, 12 ...
The support plate 16 is fixed to the hexagon bolts 12, 12 ... by turning by hand until 26 is pressed against the flange surface 28.

Next, the electric heaters 30, 30 wound around the shape memory alloys 26, 26 are energized to heat the shape memory alloys 26, 26 to a predetermined temperature. Shape memory alloy 2 due to the shape recovery force generated by heating
6 and 26 are extended to push up the support plate 16,
A predetermined tensile axial force is applied to the hexagon bolts 12, 12, ...

As for the predetermined axial force applied to the hexagon bolts 12, 12, ..., The set values of the load cells 32, 32 provided between the support plate 16 and the shape memory alloys 26, 26 ... It is controlled by setting a predetermined axial force applied to. That is, the temperature controller of the shape memory alloys 26, 26 (not shown) operates based on the set values of the load cells 32, 32 to heat the shape memory alloys 26, 26 to a predetermined temperature to generate a predetermined shape recovery force. , Is controlled by pushing up the support plate 16. Further, the load cells 32, 3 on the support plate 16 surface
Strain gauges 34, 34 ... Are respectively attached in the vicinity of the four holes into which the hexagon bolts 12, 12, ... Are inserted on the second side, and whether the axial force applied to the four hexagon bolts 12, 12 ,. Please be able to monitor it.

When a predetermined tensile axial force is applied to the hexagon bolts 12, 12, ...
14 ... The tightened state becomes loose. In this state, the four nuts 14, 14, ...
Tighten 0 and 10 by hand to tighten them fully. Next, the energization of the electric heaters 30, 30 is stopped, the shape memory alloys 26, 26 are cooled and contracted, and the hexagon bolts 12, 1
Remove the tension nuts 24, 24 ... From 2 and remove the support plate 16 from the pipe 22.

Four hexagonal bolts 12, 12 ..., Nuts 14 for connecting the pipe flanges 10 and 10 by the above-mentioned operation,
It is possible to perform the same tightening as those which are accurately tightened with a spanner (not shown) with a predetermined tightening torque. This allows the pipe flanges 10 and 10 to be attached to the bolts 12, 12 ...
Even when they are joined together, they can be fastened easily, quickly and with high precision.

According to the present invention, the bolts 12, 12 can be installed in a work space where the work for tightening the pipe flanges 10, 10 is narrow.
... In accordance with the position, the worker moves about 3 to 4 times on the diagonal line about three to four times, paying attention to the problem of tightening to a predetermined torque while performing retightening, paying attention to the bolts 12, 1
There is a great advantage in adopting a bolt tensioner system that directly generates an axial force on the bolts 12, 12 ... Instead of a torque wrench system that indirectly generates an axial force by rotating 2. That is, since a uniform axial force can be applied at once to the plurality of bolts 12, 12, ... Connecting the flanges 10, 10, it is possible to perform tightening easily, quickly, and with high precision.

In this embodiment, the shape memory alloy is arranged in the middle of the two hexagon bolts on the surface of the support plate. However, depending on the shape of the pipe flange and the set axial force, only one side or both sides of the bolt may be used. In addition, it may be arranged in other places. An electric heater was used to heat the shape memory alloy, but the present invention is not limited to this. For example, hot air is heated with a dryer or hot water is heated with a water jacket, etc. Anything that can heat the memory alloy may be used. Further, the axial force detecting member is not limited to the load cell, and may be a simple member having a strain gauge attached to a steel material as long as it can detect the shape recovery force generated in the shape memory alloy.

In this embodiment, as shown in FIG.
Although the supporting plate is a hollow quadrangular plate, it is not limited to this shape, and an easy-to-use shape such as a hollow disk can be selected according to the shape of the flange.

[0018]

As described above, according to the pipe flange tightening device of the present invention, the shape recovering force of the shape memory alloy is utilized to directly apply an axial force to the bolt for tightening the flange. It is possible to perform the same tightening as the bolt and nut for connecting with each other using a spanner with a predetermined tightening torque with high precision.

As a result, even when the flanges of the pipes are joined in a narrow working environment, it is not necessary for the operator to move in accordance with the position of the bolt, and it is not necessary to handle a tool such as a spanner in a narrow place. Bolts connecting
The nut can be tightened easily, quickly, and with high precision.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a pipe flange tightening device according to the present invention attached to a pipe.

FIG. 2 is a sectional view taken along line 2-2 in FIG.

FIG. 3 is a schematic view of a pipe flange tightening device according to the present invention when a multilayer shape memory alloy is used.

[Explanation of symbols]

 10 ... Flange 12 ... Bolt 14 ... Nut 16 ... Support plate 26 ... Shape memory alloy 32 ... Axial force detection member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Kazama 1-1-14 Kanda, Uchida, Chiyoda-ku, Tokyo

Claims (4)

[Claims] 1. A pipe flange tightening device in which a flange of one pipe and a flange of the other pipe are joined and fastened with a bolt and a nut, wherein the flange of the one pipe and the pipe of the other pipe are fastened. Temporarily fix the flange with the bolt and the nut, fix the support plate to the tip of the bolt and provide a shape memory alloy between the flange and the support plate, and heat the shape memory alloy to form the shape memory alloy. A pipe flange tightening device characterized by extending and applying a tensile axial force to a bolt, and finally tightening a nut in this state. 2. The pipe flange tightening device according to claim 1, wherein the shape memory alloy is formed by stacking two or more kinds of shape memory alloys having different transformation temperatures. 3. The pipe flange tightening device according to claim 1, wherein the shape memory alloy is a bidirectional TiNi alloy. 4. Between the support plate and the shape memory alloy,
The pipe flange tightening device according to claim 1, further comprising an axial force detection member that detects an axial force applied to the bolt.