JPH0449508Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention absorbs the thermal expansion of a thermally expanding object such as a heat transfer tube of a heat exchanger, and also has sufficient supporting force against vibrations such as earthquakes. The present invention relates to a thermal expansion absorbing device that can exhibit the following characteristics.

[Prior Art] As an example of a thermally expandable object, a thermal expansion absorber of a heat exchanger tube conventionally used in a heat exchanger is
To explain with a diagram, there are tube plates b and c on the left and right sides of the heat exchanger body a, and both ends of a large number of heat transfer tubes d arranged horizontally inside the heat exchanger body a are connected to the tube plates. It is fixed to b and c. Inside the heat exchanger tube d,
The heated fluid such as preheated air flows from the right to the left,
Outside the heat transfer tube d, a heating fluid such as exhaust gas flows from below to above to heat the fluid to be heated.

The tube plate b on the left side is fixed to the heat exchanger body a, but the tube plate c on the right side is not fixed to the heat exchanger body a, but is made so that it can be displaced left and right with respect to the heat exchanger body a. The tube plate c is supported by the spring e, and the other end of the spring e is held down by a bracket f fixed to the heat exchanger body a.

When the heat exchanger tube d expands due to the heat of the heating fluid, the tube plate c compresses the spring e and is displaced to the right, causing the heat exchanger tube d to expand.
This prevents damage to tube sheets b, c and heat exchanger tubes d by absorbing the expansion. Furthermore, in response to vibrations caused by earthquakes, etc., the initial repulsive force of the spring e prevents the tube plate c from being displaced.

[Problem to be solved by the invention] As the expansion of the heat transfer tube d increases, the spring e
As a result of the increase in the reaction force of the heat transfer tube d and the tube sheet b,
The structure of c must be made stronger. However, making the structure stronger increases the overall weight and the cost. To prevent this, it would be possible to use a long spring with a small spring constant, but the installation space for the spring is limited to a small space, so it was not possible to use a long spring with a small spring constant.

An object of the present invention is to provide a thermal expansion absorbing device that requires a small installation space, has a small spring reaction force, and does not require strengthening the structure.

[Means for Solving the Problems] The present invention provides a second end that is connected to a thermally expandable object and whose other end is supported by a latch that is pressed by the expansion of the thermally expandable object and releases when a force exceeding a certain value is applied. one spring, one end is free and the other end is attached to a fixed member, and the one end is connected from the other end of the first spring when the other end of the first spring is supported by the latch. A second spring is spaced apart and is pressed by the other end of the first spring when the latch is released.

[Function] When the spring reaction force of the first spring is below a certain value, the expansion of the thermally expanding object is absorbed by only the first spring, but when the spring reaction force of the first spring exceeds a certain value, When the latch is released, the first spring is extended by the distance, and the expansion of the thermally expandable object is absorbed by the first spring and the second spring with less reaction force.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 1, the left end of the heat exchanger tube shown as an example of the thermal expansion object 1 is fixed to a fixed tube plate 2, and the right end is fixed to a tube plate 3 that can be displaced from side to side. One end of a first spring 4 is connected to the right end of the thermal expansion object 1 via a tube plate 3.
A support plate 5 is attached to the other end of the spring 4 , a support plate 5 is attached to the other end of the first spring 4 , and the other end of the first spring 4 is attached to the other end of the first spring 4 through the support plate 5 . It is designed to be supported by the tip of the latch 6.

The latch 6 has its base end pivotally connected to a fixing member 8 such as a heat exchanger body through a hinge 7, and is biased by a reaction spring 9 in a direction to displace the tip of the latch 6 to the left. Therefore, the spring force at the other end of the first spring 4 described above is applied to the reaction spring 9 via the support plate 5 and the latch 6.

The other end of the first spring 4 is connected to the latch 6 via the support plate 5.
When the second spring 11 is supported by the first spring 4, one end of the second spring 11 is positioned at a distance of 10 from the other end of the first spring 4. The second spring 11 is placed on an extension of the first spring 4, and the other end of the second spring 11 is attached to the fixing member 8.

When the thermally expandable body 1 thermally expands, the tube sheet 3 is displaced to the right in FIG. 1, compressing the first spring 4. At this time, the relationship between the amount of displacement of the tube sheet 3 and the spring reaction force applied to the tube sheet 3 changes along the OA line in FIG. 2. When the first spring 4 is compressed, the reaction spring 9 is also compressed, and the tip of the latch 6 is also compressed by the support plate 5.
However, if the magnitude of the reaction force of the first spring 4 is less than F2 in Fig. ₂ , the latch 6 will not come off the support plate 5. ing. Therefore, in a range where the amount of thermal expansion of the thermally expandable object 1 is small, the first spring 4 absorbs the thermal expansion. In addition, vibrations caused by ordinary earthquakes, etc.
It is supported by a first spring 4 to prevent damage.

However, the amount of thermal expansion of the thermally expandable object 1 increases, and the spring reaction force of the first spring 4 increases as shown in FIG.
When F ₂ is exceeded, the amount of rotation of the latch 6 around the hinge 7 exceeds a certain level, and the latch 6 comes to come off from the support plate 5 . When the latch 6 is removed from the support plate 5, the other end of the first spring 4, which was supported by the latch 6 via the support plate 5, becomes free, and the support plate 5
At the same time, it suddenly shifts to the right by an interval of 10,
It comes into contact with one end of the second spring 11 and stops. The first spring 4 is therefore expanded by the dimension of the distance 10 and the spring reaction force is reduced from F ₂ in FIG. 2 to F ₁ .
At this time, the amount of displacement of the tube plate 3 is _S1 .

From the state where the amount of displacement of tube sheet 3 is S ₁ , the amount of thermal expansion of thermal expansion object 1 further increases, and the amount of displacement of tube sheet 3 becomes
When _S1 is further increased, the first spring 4 and the second spring 11 are in series, and both are connected to the thermal expansion object 1.
This will absorb the thermal expansion of Therefore, the spring reaction force against the displacement becomes smaller than when the first spring 4 absorbs thermal expansion alone, and as shown in FIG.
It will change along the BC line. Therefore, when the displacement amount of the tube sheet 3 reaches _S2 , if the first spring 4 is absorbing the thermal expansion alone, the spring reaction force will be large _F4 , but the latch 6 and the spacing 10 By providing the second spring 11, only a small spring reaction force of F ₃ is required, and the stress applied to the thermal expansion object 1 and the tube sheets 2 and 3 is reduced, so the strength is reduced and the weight is reduced. It can be done.

Furthermore, by providing a large number of combinations of the latch 6, the spacing 10, and the second spring 11 in series, it is possible to avoid increasing the spring reaction force even when the amount of displacement increases, as shown in FIG. You can also do it.

[Effects of the Invention] According to the present invention, even when the amount of thermal expansion of a thermally expandable object increases, the reaction force of the spring that absorbs this thermal expansion decreases stepwise, and the spring reaction force can be alleviated.

[Brief explanation of the drawing]

Figure 1 is a side view of an embodiment of the present invention; Figure 2 is a side view of an embodiment of the present invention;
Figure 3 is a graph showing the relationship between displacement and spring reaction force.
FIG. 4 is a sectional view of an example of a conventional thermal expansion absorbing device. 1 is a thermal expansion object, 4 is a first spring, 6 is a latch,
10 indicates the interval, and 11 indicates the second spring.

Claims (1)

[Scope of utility model registration request] A first spring whose one end is connected to a thermally expandable object and whose other end is supported by a latch that is pressed by the expansion of the thermally expandable object and releases when a force of a certain value or more is applied; one end is free and the other end is fixed; attached to the member, and
The one end is spaced apart from the other end of the first spring when the other end of the first spring is supported by the latch, and is pressed by the other end of the first spring when the latch is released. A thermal expansion absorption device characterized by comprising: a second spring that is