JPS6056995B2 - Shell-and-tube heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-tubular heat exchanger in which a plurality of heat transfer tubes are arranged in an outer cylinder or outer tube, and in particular, a refrigerant inflow chamber is formed with divided inflow chambers for each heat transfer tube. The present invention also relates to a multi-tube heat exchanger in which a guide member is provided at the end of the protruding tube of the transmission port to evenly distribute the refrigerant flowing into each heat transfer tube.

The description of the shell-and-tube heat exchanger of the present invention refers to a so-called shell-tube heat exchanger in which a large number of heat transfer tubes are arranged in a relatively large-diameter outer cylinder, and a shell-tube heat exchanger in which a large number of heat transfer tubes are arranged in an outer tube with a smaller diameter than a shell-tube heat exchanger. This includes a so-called shell-and-tube heat exchanger in which a plurality of heat transfer tubes are arranged and the outer tubes are relatively long, so the outer tubes are appropriately wound after the heat transfer tubes are installed.

First, a conventional shell-and-tube heat exchanger will be explained using a shell-tube heat exchanger shown in FIG. 1 as an example.

In the figure, 1 is an outer cylinder, with tube sheets 2 and 3 fixed to both sides of the outer cylinder, and between both tube sheets 2 and 3, a large number of heat transfer tubes 4 are installed between both tube sheets 2 and 3.
3 are inserted in close contact with each other. 5 is an inlet pipe for the fluid to be cooled provided on one side of the outer cylinder 1, and 6 is an outlet pipe provided on the other side.

Covers 7 and 8 are arranged on the outside of both the tube plates 2 and 3, respectively, and one cover 7 divides a cover chamber formed by the cylinder 7' and the side plate 7'' with a partition wall 9, and It is fixed to the plate 2 by welding or bolts, etc., and forms a refrigerant inflow chamber 10 and a refrigerant outflow chamber 11.A refrigerant inflow pipe 12 is connected to the refrigerant inflow chamber 10, and a refrigerant outflow pipe 13 is connected to the refrigerant outflow chamber 11, respectively. ing.

The cover 8 on the other side is formed of a cylindrical body 8'' and a side plate 8'', and is fixed to the tube plate 3 by welding or bolts, forming a refrigerant return chamber 14, and allowing a large number of heat transfer tubes to enter the refrigerant. They are formed into a heat transfer tube group 4'' that flows from the chamber 10 to the refrigerant return chamber 14, and a heat transfer tube group 4'' that flows from the refrigerant return chamber 14 to the refrigerant outflow chamber 11. The effect of using the shell-tube heat exchanger having the above structure in a cooler (evaporator) of a refrigeration system will be explained. The gas-liquid two-phase refrigerant, which is partially vaporized after being depressurized through a decompression mechanism (not shown) such as an expansion valve of the refrigeration system, flows through the refrigerant inlet pipe 1.
2, the refrigerant flows into the inflow chamber 10 and is distributed to the chamber 1.
It flows into the heat exchanger tube group 4'' opening at 0, flows to the right through the tubes, reaches the refrigerant return chamber 14, curves upward in the return chamber 14, and flows into the upper transmission tube group 4'' connected to the refrigerant outflow chamber 11. It flows into the heat tube group 4'', flows through the tube group to the left, and reaches the refrigerant outflow chamber 11,
Next, the refrigerant is sucked into the suction side of a compressor (not shown) through the refrigerant outlet pipe 13. In the above-mentioned circulation process, the refrigerant flowing through the pipe exchanges heat with a fluid to be cooled, which will be described later, and absorbs heat from the fluid to be cooled, and is vaporized.

On the other hand, the fluid to be cooled, such as water or brine, which has flowed into the outer cylinder from the inlet pipe 5 flows between the heat transfer tube groups and is cooled by exchanging heat with the above-mentioned circulating refrigerant during this circulation process.
It flows out of the vessel and is used for various purposes.

FIG. 2 shows the part where the heat exchanger tube 4 and the tube sheets 2 and 3 are in close contact with each other. Keeping the area airtight.

Generally, the tube ends 4e of the heat exchanger tubes 4 protrude several times from the tube plate due to manufacturing reasons.

Further, FIG. 3 shows the arrangement of heat exchanger tubes in the cover chamber. A large number of heat exchanger tubes are inserted through the tube sheets 2 and 3, and since the outer cylinder 1 is generally circular, the heat exchanger tubes 4 are Regarding the number of heat transfer tubes arranged in each stage, the number of heat exchanger tubes is greater in the middle stage in the outer cylinder than in the upper and lower stages.

That is, in the refrigerant inflow chamber 10, which is separated from the refrigerant outflow chamber 11 by the partition wall 9, there are more heat exchanger tubes in the upper stage 4''a than in the lower stage 4''d.

The gas-liquid two-phase refrigerant, which has been depressurized and partially vaporized through the decompression device (not shown) of the refrigeration system described above, flows into the refrigerant inflow chamber 10 through the refrigerant inflow pipe 12 in the form of a jet, and then flows into the heat transfer tube group. 4
However, the weight flow rate of the refrigerant flowing into each heat exchanger tube group 4'' is not the same across each heat exchanger tube, and the refrigerant inlet chamber 1
At 0, the number of upper heat exchanger tubes 4''a is the least, and the number of lower heat exchanger tubes 4''d is the largest.

This phenomenon is caused by the fact that even though the injected inflow refrigerant is distributed in the same amount throughout the refrigerant inflow chamber 10, the gas-liquid two-phase refrigerant is also present on the wall surface of the tube plate 2 holding each heat transfer tube 4. The liquid refrigerant that is being injected and hits this wall cannot flow into the heat transfer tube because the tube end 4e projecting into the refrigerant inflow chamber 10 acts as a screen, as shown in FIG. The liquid refrigerant descends along the outer wall and tube plate wall of the protruding tube end 4e due to its own weight and the subsequent injection refrigerant, and the liquid refrigerant accumulates in the lower part of the refrigerant inlet chamber 10.

Therefore, the refrigerant flowing into the lower heat exchanger tube 4''a has a large proportion of liquid refrigerant, and the refrigerant flowing into the upper heat exchanger tube 4''a has a small proportion of liquid refrigerant. For this reason, the pressure loss is larger in the upper heat exchanger tube 4''a, and the flow rate of refrigerant flowing into each heat exchanger tube becomes even more uneven.As a result, most of the heat exchange amount in the heat exchanger tube group 4'' is The upper heat exchanger tube 4''a is occupied by the middle and lower heat exchanger tubes and is not effectively utilized.

However, the cross section of a shell-and-tube heat exchanger is often circular as shown in FIG. Although the number of heat exchanger tubes is used effectively, it is larger than the number of heat exchanger tubes in the lower tier, and this is a major cause of performance deterioration.

The present invention was invented in view of the above, and aims to equalize the distribution of refrigerant flowing into each heat exchanger tube, and the present invention aims to equalize the distribution of the refrigerant flowing into each heat exchanger tube, and to provide a refrigerant inflow chamber for each stage or multiple stages of heat exchanger tubes that open into the inflow chamber. A divided inflow chamber is formed in each of the divided inflow chambers, and an appropriate number of refrigerant branch inflow pipes are inserted into each of the divided inflow chambers, and a guide member for guiding the inflow of the refrigerant is arranged at the inlet of the heat transfer tube to control the amount of inflow refrigerant. The refrigerant is configured to flow into each divided inflow chamber according to the ratio of the number of heat transfer tubes in the inflow chamber, and to facilitate the flow into each heat transfer tube by a guide member, thereby equalizing the weight flow rate of the refrigerant flowing into each heat transfer tube. There is. An embodiment of the present invention will be explained using a shell-tube heat exchanger shown in FIGS. 4 and 6.

In the figure, the same parts as in the conventional example are given the same reference numerals, and the explanation thereof will be omitted.

In Fig. 4, the difference from the conventional example is that a funnel shape is inserted into the protruding tube end of each heat exchanger tube at the inlet of each heat exchanger tube group 4'' of the refrigerant inflow chamber, and each funnel shape is formed into a flat wall. A semi-circular guide member 20 is arranged which is integrally connected to the
The heat exchanger tubes are divided into respective stages by substantially L-shaped dividing partition plates 23 to form divided inflow chambers, and an appropriate number of branched inflow pipes 24 are connected to each divided inflow chamber.

Other parts are similar to the conventional example.

5 and 6 are enlarged views of the refrigerant inflow chamber, and the guide member 20 has funnel-shaped openings formed in a semicircular metal plate having the same area as the refrigerant inflow chamber 10 at positions corresponding to the heat transfer tubes. However, each funnel piece 2' is connected to a plane wall 2'.

The guide member 20 has a funnel piece 2'' attached to the tube end 4''E of each heat transfer tube.
is inserted and placed.

Next, the dividing partition plate 23 is a metal plate bent into an L shape and having a length that touches the cylinder body 7''.
, 4''C, 4''D, 4''n opening spaces are partitioned, the refrigerant inflow chamber 10 is divided into each stage of the heat transfer tube, and the divided inflow chamber 10 is divided.
a, 10b, 10c, 10d, 10e, and 10n, and the dividing partition plate 23 is provided with an appropriate number of insertion holes 25 having a larger diameter than the branch refrigerant inlet pipe 24.

A refrigerant inflow pipe (not shown) is branched into a plurality of divided inflow chambers 10a, 10b, 10c, 10d, 10e, 10.
An appropriate number of branch refrigerant inflow pipes 24a, 24b, 24c, 24d, 24e, 24n depending on the ratio of the number of heat exchanger pipes opened to
is tightly fitted through the side plate 7'', and is further extended to form holes 25 in the divided inflow chambers 10a, 10b, 10c, 10d, and 10e.
inserted into the inflow chambers 10a, 10b, 10c, 10d.
, 10e, and the branch refrigerant inflow pipe 24n directly opens into the branch refrigerant inflow chamber 10n.

The guide member 20 and the partition plate 23 are fixed together in advance and are disposed in the refrigerant inflow chamber 10 .

This integral member of the guide member 20 and the dividing partition plate 23 is pushed in the flow direction by the flow velocity of the refrigerant, and the guide member 20
The outer periphery of the partition plate 23 and both ends of the partition plate 23 are in contact with the cylindrical body 7'', so that they are fixed without the need for separate fittings or processing for attachment and fixation.

As in the above structure, the heat transfer tubes of the refrigerant inflow chamber 10 are divided into divided inflow chambers 10a, 10b, .
4d, 24e, and 24n are opened into the respective divided inflow chambers, and a guide member 20 is provided at the tube end of each heat transfer tube, eliminating the protruding tube end.
4c, 2.4d, 24e, 24n, each divided inflow chamber 10a, 10b, 10c, 10d, 10e, 10n has heat transfer tubes 4''A, 4''B, 4''C, which open into the inflow chamber.
The refrigerant with a weight flow rate corresponding to the number of refrigerant 4''D, 4''E, 4''n flows toward the guide member 20 in a spray shape, and the funnel piece 2
The refrigerant that was injected into the plane wall 2' flows through the wall 2' and easily flows into the funnel-shaped 2', and the refrigerant that could not flow into the funnel-shaped 2' temporarily flows into the funnel-shaped part 2'. room 10
a, 10b, 10c, 10d, 10e, 10n, and is attracted to the subsequent inflowing refrigerant flow and divided into the inflow chambers 10a and 10n.
The refrigerant is injected into the guide member 20 again by the swirling flow within 10n.

Since the above action is performed continuously, the divided inflow chamber 10a
...10n almost all of the refrigerant evenly flows into the heat exchanger tubes of each divided chamber, and all of the heat exchanger tubes ``a...4
″n almost equally.

FIG. 7 shows another embodiment. In contrast to the structure of the above embodiment in which a partition wall is provided for each stage of heat exchanger tubes and a divided inlet chamber is formed for each stage of heat exchanger tubes, a partition wall is provided for each stage of heat exchanger tubes. A wall is provided to form divided inflow chambers for each of multiple stages of heat exchanger tubes, and the same parts as in FIG. 6 are given the same reference numerals and their explanation will be omitted. In FIG. 7, a partition wall 23'' is provided for every two stages of heat exchanger tubes, and each heat exchanger tube opening is divided into an inflow chamber 1 for every two stages of heat exchanger tubes.
01, 102, . . . and branch refrigerant inflow pipes 241 . . . are arranged in each divided inflow chamber.

In this case, it is desirable that the branch refrigerant inflow chambers 241 are arranged so as to open at the lower positions of the respective divided inflow chambers 101, 102, . This embodiment is suitable when the outer diameter of the heat exchanger tube is relatively small and there are many stages of heat exchanger tubes. Even if divided inlet chambers are formed for each stage, the vertical length (height) of each divided inlet chamber is Since the length is not so long, the refrigerant flows sufficiently into the heat exchanger tubes at the upper stage of each divided inflow chamber, so that the same effects as in the previous embodiment can be achieved.

As another example, although not shown, a plurality of branched refrigerant inflow pipes are provided in the divided inflow chambers 10a, 10b, . . . , and no branched refrigerant inflow pipe is provided in the lower divided inflow chamber 10n. The refrigerant leaking from the insertion holes 25 of 10a, 10b, and the gap between the partition plate 23 and the cylinder 7'' may be made to flow into the lower heat exchanger tube 4''n.

In addition, as another embodiment, a vertical partition plate may be provided in the divided inflow chamber according to the number of branch refrigerant inflow pipes inserted into each divided inflow chamber, and the amount of refrigerant flowing into each heat transfer tube opening into the divided inflow chamber is can be made even more uniform.

As explained above, according to the present invention, the refrigerant flowing into each heat exchanger tube has a fairly uniform refrigerant weight flow rate, so all the heat exchanger tubes can be used effectively, the usable area increases, and the amount of heat exchange is increased. be able to.

In addition, in a heat exchanger that requires the same amount of heat exchange, the number of heat transfer tubes can be reduced compared to conventional ones, making it smaller and lighter than before, and the integral member consisting of the guide member and partition plate can be replaced with separate mounting brackets or It is easy to manufacture because it can be assembled without requiring any processing to fix it.

It has the following effects.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional shell-and-tube heat exchanger, and Figure 2 is a cross-sectional view of a conventional shell-and-tube heat exchanger.
Figure 3 is an enlarged cross-sectional view of the heat exchanger tube contact part shown in Figure 1.
■An enlarged partial view of a cross-sectional view taken along the line, FIG. 4 is a cross-sectional view of a multi-tubular heat exchanger showing an embodiment of the present invention, and FIG. 5 is an enlarged cross-sectional view of the refrigerant inflow chamber portion of FIG. 4. . 6 is a partial sectional view taken along the line E in FIG. 5, and FIG. 7 is a sectional view showing another embodiment at the same position as FIG. 6.

Claims (1)

[Claims] 1 A plurality of heat exchanger tubes are arranged in an outer cylinder via a tube plate, the tube ends of the heat exchanger tubes protrude from the tube plate, and the protruding tube end openings of each heat exchanger tube are covered with a side plate and a cylinder body. A chamber is formed;
In a shell-and-tube heat exchanger, the cover chamber is divided into a refrigerant inflow chamber and a refrigerant outflow chamber, and a refrigerant is flowed into the heat transfer tubes and a fluid to be cooled is flowed outside the tubes to exchange heat with each other. A funnel-shaped opening is formed corresponding to the opening position of the heat exchanger tube, and a substantially L-shaped partition plate that partitions the funnel-shaped opening into a plurality of rows is fixed to the semicircular plate. An integral member of the semicircular plate and the substantially L-shaped partition plate, each of which has a refrigerant inflow pipe insertion hole drilled in one side of each of the opposing partition plates, is inserted into the cylinder, and the inner wall of the cylinder and the substantially L-shaped partition plate are connected to each other. The refrigerant inflow chamber is divided for each stage row by a semicircular plate to form divided inflow chambers, and a plurality of branched refrigerant inflow pipes passing through the side plate are inserted into the refrigerant inflow pipe insertion hole, and the integral member is inserted into the refrigerant inflow chamber. A multi-tube heat exchanger characterized by being compressed by the flow rate of refrigerant.