JPH0531079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a heat exchanger used, for example, in a Stirling engine, and particularly to a heat exchanger with excellent assembly performance.

[Technical background of the invention and its problems]

The Stirling engine is a hot gas reciprocating engine that drives pistons in expansion and compression cylinders by thermal expansion and contraction of a working fluid.

FIG. 1 is a diagram showing a schematic configuration of such a Stirling engine, and numerals 1 and 2 in the figure are an expansion cylinder and a compression cylinder, respectively, which are vertically bored in the upper part of the crank chamber 3. An expansion piston 4 is housed inside the expansion cylinder 1 so as to be able to freely reciprocate, and a compression piston 5 is housed inside the compression cylinder 2 so that it can freely move back and forth. Inside the crank chamber 3, a crankshaft 8 whose rotational axis is perpendicular to the reciprocating direction of the pistons 4 and 5 is housed and rotatably supported by bearings 9 and 10. Both pistons 4 and 5
are connected to the crankshaft 8 via connecting rods 11 and 12, respectively, in such a manner that they reciprocate while maintaining a phase difference of, for example, 90 degrees.

The inside of the expansion cylinder 1 and the inside of the compression cylinder 2 are connected via a working fluid path 13.
A heater 14, a regenerator 15, and a cooler 16 are connected in series to this working fluid path 13 in this order from the expansion cylinder 1 side to the compression cylinder 2 side. The heater 14 and the cooler 16 each consist of a heat exchanger with a high temperature source and a low temperature source. The inside of the working fluid path 13 and each cylinder 1, 2 is filled with a working fluid P made of a non-condensable gas such as He, _H2 , _N2, etc.

In the Stirling engine configured in this way, when the compression piston 5 is now at the top dead center and the expansion piston 4 is in the downward process, the working fluid P flows through the working fluid path 13 from the compression cylinder 2 to the expansion cylinder 1 in the figure. Move in the direction of the solid arrow. The working fluid P is heated by the heater 14 during this movement process. When the working fluid P is heated in this way, the working fluid P expands, and this gas pressure moves the expansion piston 4 downward in the figure. At this time, the compression piston 5 begins to descend, and the working fluid P moves through the working fluid path 13 from the expansion cylinder 1 to the compression cylinder 2 in the direction of the dotted line arrow in the figure. During this movement, the working liquid P gives heat to the heat storage agent inside the regenerator 15 and is cooled by the cooler 16. When the working fluid P is cooled in this way, the working fluid P contracts and causes the compression piston 5 to rise. The working fluid P is further compressed by this compression stroke. At this time,
Since the expansion piston 4 begins to descend, the working fluid flows again to the expansion cylinder 1 side, takes away the heat stored in the regenerator 15, and one cycle ends.

In this way, the Stirling engine has an expansion cylinder 1, a heater 14, a regenerator 15, and a cooler 1.
6 and the compression cylinder 2 constitute a closed flow path for the working fluid P, but within this closed flow path, the original space that is directly involved in the output is the stroke volume of the expansion cylinder 1 and the compression cylinder 2. , the other spaces are dead volumes. Therefore, it is desirable that this ineffective volume be as small as possible.

However, if the cross-sectional area of the working fluid is made too small in order to reduce this ineffective volume,
There is a problem in that the flow resistance of the working fluid increases, which ultimately leads to a decrease in output.

On the other hand, in this type of hot gas reciprocating engine,
The lower the temperature of the working fluid on the low-temperature side and the higher the temperature of the high-temperature side of the working fluid, the higher the engine efficiency. Therefore, it is desirable that the heat exchangers constituting the heater 14 and the cooler 16 have high heat exchange efficiency.

Therefore, in order to satisfy these demands, in this type of hot gas engine, the heat exchanger has a large number of meanderingly bent tubular heat exchanger bodies 2, as shown in FIG.
1 are arranged in parallel. With this configuration, the heat transfer area between the first heat medium Q flowing through the inside of the heat exchanger body 21 and the second heat medium R flowing through the outer surface of the heat exchanger body 21 is increased. be able to.

Each heat exchanger main body 21 is constructed by coaxially inserting a dummy rod 23 whose outer diameter is smaller than the inner diameter of the pipe 22 into a meandering bent pipe 22, as shown in FIG. , the inner surface of the pipe 22,
A working fluid flow path is formed between the dummy rod 23 and the dummy rod 23. A positioning member 24 is interposed between the pipe 22 and the dummy rod 23 at a predetermined position in the axial direction so that the flow path having a thin and uniform thickness can be maintained at all times.

By configuring the heat exchanger main body 21 in this way, it is possible to reduce the ineffective volume without causing a decrease in the heat transfer area, and it is also possible to improve the heat exchange efficiency.

However, such a heat exchanger has the following problems.

That is, since the dummy rod 23 is a rigid body, it is necessary to insert the dummy rod 23 into the inside of the pipe 22 before bending the pipe 22, as is clear from the above structure. Therefore, pipe 22
The bending of the dummy rod 23 is performed after the dummy rod 23 is inserted into the pipe 22. Therefore, the task of aligning the axial center of the dummy rod 23 with the axial center of the pipe 22 is extremely troublesome, leading to a complicated work process.

Additionally, due to this, the axes of the two may be extremely misaligned, the uniformity of the flow path may be impaired, the heat exchange efficiency may be reduced, and if the two come into contact, the contact area may be There was a problem in that the pipe 22 became a concentrated load point and heat point, and excessive thermal stress was applied to the pipe 22, resulting in a decrease in reliability.

[Purpose of the invention]

The present invention has been made based on these conventional drawbacks, and its purpose is to reduce the dead volume and improve heat exchange efficiency by inserting a dummy rod inside the heat medium flow pipe. In a heat exchanger designed to improve heat exchange efficiency, it is possible to simplify manufacturing and improve the accuracy of the positional relationship between the heat medium flow pipe and the dummy rod, resulting in excellent heat exchange efficiency and reliability. The objective is to provide a heat exchanger that

[Summary of the invention]

In the present invention, a dummy rod is coaxially inserted inside a partially bent heat medium flow pipe, and a heat medium flow path is formed between the inner surface of the heat medium flow pipe and the dummy rod. The heat exchanger is characterized in that the dummy rod is constituted by a plurality of divided bodies arranged in the axial direction and a connecting member that connects these divided bodies in a flexible manner.

〔Effect of the invention〕

According to the present invention, the dummy rod includes a plurality of divided bodies;
Since these are configured with a linking member that connects them in a flexible manner, the degree of freedom in the shape of the dummy rod can be increased. Therefore, it is possible to insert the dummy rod later into the heat medium flow tube which has been bent in advance. Therefore, it is possible to improve the productivity of the heat exchanger.

In addition, since the degree of freedom of the dummy rod increases as described above, by providing an appropriate positioning member between the dummy rod and the heat medium flow pipe, the dummy rod can be easily coaxially attached to the heat medium flow pipe. can be placed.

Further, according to the present invention, since the dummy rod can be removed individually after the heat exchanger is assembled, there is also an advantage in terms of maintenance of the heat exchanger.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described based on FIG. 4.

The heat exchanger main body 31 shown in FIG. 4 is one of a plurality of heat exchanger bodies arranged in parallel as shown in FIG. 2, and 32 in the figure is a pipe serving as a heat medium flow pipe. This pipe 32 is meanderingly bent so as to increase the heat transfer area of the heat medium as much as possible, and a dummy rod 33 is coaxially arranged inside the pipe 32. This dummy rod 33 passes through a plurality of cylindrical divided bodies 34 arranged with slight gaps in the axial direction and a hole 35 provided at the axial center of these divided bodies 34, so that the divided bodies 34 are mutually connected. and a connecting wire 36 that connects the two. Between the pipe 32 and the dummy rod 33, a positioning member 37 is provided at a predetermined position in the axial direction in order to arrange the dummy rod 33 coaxially with the pipe 32 with high precision.
I am trying to intervene. The tips of the divided bodies 34a and 34b at both ends of the dummy rod are tapered so that the dummy rod 33 can be easily inserted into the pipe 32.

With such a configuration, the heat exchanger main body 31 can be assembled as follows.

That is, the pipe 31 is bent and formed as a single piece in advance. The bent pipe 31 is fixed to, for example, a flange portion (not shown). Thereafter, the above-described dummy rod 33 is inserted into the pipe 32. The positioning member 37 is attached to the pipe 32 in advance.
or the outer surface of the dummy rod 33. When the dummy rod 33 reaches the bend of the pipe 32, the connecting wire 36 connecting the divided bodies 34 is deformed, and the entire dummy rod 33 moves along the inner surface of the pipe 32. Since a positioning member 37 is fixed to the inner surface of the pipe 32 or the outer surface of the dummy rod 33, the dummy rod 33
will be arranged coaxially within the pipe 32.

In this way, according to this embodiment, the dummy rod 33 can be coaxially inserted into the bent pipe 32 without any difficulty. Therefore, it is possible to provide a heat exchanger with excellent manufacturability. Furthermore, the presence of the positioning member 37 allows the axes of the pipe 32 and the dummy rod 33 to be aligned accurately, so that a uniform flow path can be formed. Therefore, the heat exchange efficiency is also extremely good.

Note that the present invention is not limited to the embodiments described above.

For example, if the split body 34 and the connecting wire 36 are connected in a loosely fitted state, when the dummy rod 33 is inserted into the pipe 32, the connecting wire 36 serving as a guide is first attached to the inside of the pipe 32. However, the heat exchanger main body may be constructed by sequentially attaching the divided bodies 34 to the connecting wire 36.

Further, the member for connecting the divided bodies is not limited to a wire-like member, but may be, for example, a metallic mesh-like member. In this case, the dummy rod may be configured so that the mesh-like connecting member wraps around the divided body.

Furthermore, it goes without saying that the present invention is not particularly limited to heat exchangers used in Stirling engines, but can also be applied to other heat engines, such as gasoline engines, diesel engines, and various power generation plants. do not have.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the schematic configuration of a Stirling engine, Fig. 2 is a perspective view showing the main parts of a heat exchanger used in the engine, and Fig. 3 is a vertical cross-section of the heat exchanger main body of the heat exchanger. 4 are longitudinal sectional views showing a heat exchanger main body in a heat exchanger according to an embodiment of the present invention. 1... Expansion cylinder, 2... Compression cylinder, 3
... Crank chamber, 4 ... Expansion piston, 5 ... Compression piston, 8 ... Crankshaft, 9, 10 ... Bearing, 11, 12 ... Connecting rod, 13
... Working fluid path, 14 ... Heater, 15 ... Regenerator, 16 ... Cooler, 21, 31 ... Heat exchanger body, 22, 32 ... Pipe, 23, 33 ... Dummy rod, 24 , 37... Positioning member, 34... Divided body, 35... Hole, 36... Connection wire, P...
Working fluid, Q, R... heat medium.

Claims (1)

[Claims] 1. A dummy rod is coaxially inserted into a partially bent heat medium flow pipe, and the heat medium is passed between the inner surface of the heat medium flow pipe and the dummy rod. In the heat exchanger that forms a flow path, the dummy rod is composed of a plurality of divided bodies arranged in the axial direction and a connecting member that connects these divided bodies in a flexible manner. heat exchanger. 2. The heat exchanger according to claim 1, wherein the connecting member is made of a flexible member.