JPH0412372Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a foam extinguishing plate installed in the trough of an open rack heat exchanger, and more specifically, the invention relates to a foam extinguishing plate provided in the trough of an open rack heat exchanger. This invention relates to a foam extinguishing plate for an open-rack heat exchanger, which homogenizes the flow of the heat transfer medium in the trough and homogenizes the contact of the heat transfer medium flow with the panel surface to ensure stable heat exchange operation. be.

[Prior art] Open rack heat exchangers are commonly used to vaporize cryogenic liquefied natural gas, etc.
A typical example of the open rack type heat exchanger is shown in FIG. That is, the open rack heat exchanger 7 includes an upper header 3, a lower header 4, a large number of heat exchanger tubes 1 disposed between the upper header 3 and the lower header 4, and fins 2 arranged in parallel with the heat exchanger tubes 1. , a trough 6 that runs approximately horizontally in the vicinity of the upper header 3, and a supply pipe 8 that supplies a heat transfer medium such as seawater (the case of using seawater will be described below) to the trough 6.

The seawater supplied into the trough 6 by the supply pipe 8 flows over the side wall of the trough 6 on the panel side, and the seawater flows over the side wall of the trough 6 on the panel side, and the seawater flows over the side wall of the trough 6 on the panel side. It falls while forming a film-like seawater flow along the surface of 5. On the other hand, the low-temperature fluid and the like are rising inside the heat transfer tube 1, and heat exchange is performed by thermal contact between the rising low-temperature fluid and the seawater at the panel 5.

By the way, such an open rack heat exchanger 7
In the trough 6, many air bubbles are generated in the process in which seawater is rapidly dropped and supplied from the supply pipe 8. As mentioned above, the bubbles are caused by seawater flowing into the trough 6.
When overflowing, the trough 6 is overflowed with the seawater,
While contacting the surface of the panel 5, the seawater falls gently due to the falling flow of seawater. If air bubbles come into contact with the surface of the panel 5 and are interposed between the seawater falling film and the panel 5 in this way, they will act as a shield for the heat exchange and will have a negative effect on the heat exchange performance of the heat exchanger.

In order to eliminate these harmful effects, a foam extinguishing board 9 as shown in FIG. 3 is used, but the foam extinguishing board 9 is
It is attached in the shape of a collar to the tip of the supply pipe 8 via the top plate 9a, and is installed in the trough 6 so that the longitudinal direction of the trough 6 (FIG. 2) is along the X-Y direction in FIG. 3. Here, the gouge weir 9b is the lower edge 90 of this
b is immersed in the seawater in the trough 6 while maintaining a distance from the bottom surface of the trough 6. As mentioned above, air bubbles are generated in the seawater introduced into the trough 6, and the air bubbles either collide with the sinkhole 9b due to the water flow during the seawater supply, or float to the surface by their own buoyancy and connect with the water surface. The foam gathers in the narrow space between the plates 9a, presses each other, and disappears.

[Problems that the invention aims to solve] Although the foam extinguishing board certainly exhibits the above-mentioned effects, the use of the foam extinguishing board brings about other problems that have not been experienced before. It was found that this occurs. In other words, when there is no foam extinguishing plate, and therefore no sink weir, seawater that falls into the trough immediately spreads along the length of the trough, and as a result, overflow from the trough side walls is almost uniform over the entire length of the trough. However, when foam extinguishing plates were used, the overflow state tended to be uneven over the entire length of the trough, which appeared to cause variations in the heat exchange on the panel surface. Therefore, we thought it necessary to clarify the situation during this time, and measured the seawater flow rate at each point in the longitudinal direction of the trough in which the foam extinguishing board 9 was installed, and obtained the results shown in Figure 7. . In this trough, a rectifying plate was provided in a region defined by the foam extinguishing plate 9 and the side wall 6a of the trough 6 (FIG. 2) in an effort to equalize the amount of seawater overflowing in the longitudinal direction of the trough. However, as shown in Figure 7, the amount of seawater overflowing was clearly non-uniform in the longitudinal direction of the trough. FIG. 4 is a schematic plan view for explaining the reason for this in principle. Seawater supplied through the supply pipe 8 is obstructed from flowing in the longitudinal direction of the trough by the submerged weir 9b, so most of the seawater is perpendicular to the top plate 9a of the foam extinguishing board 9 as shown by arrows 11 and 12. flows in the direction. Therefore, the portion 13 shown by crosshatching in the figure is in a so-called "stagnant" state, and the flow velocity is lower than that in other portions. Such a flow situation is basically the same even when the above-mentioned current plate is provided. When the flow condition becomes non-uniform in this way, the overflow to the panel 5 also becomes non-uniform, resulting in non-uniformity of the film-like seawater flow and a decrease in heat exchange performance.

However, not only that, but if the stagnation of seawater continues for a long period of time, marine organisms will appear and proliferate near the stagnation area. These marine organisms reduce the efficiency of the maintenance work of the trough and further promote the unevenness of the flow conditions, so in this sense as well, the word "stagnant" is used.
It is important to avoid the situation.

The present invention was developed in consideration of these circumstances, and in addition to effectively exhibiting the original function of the foam extinguishing board, it also makes the flow rate of the heat transfer medium in the longitudinal direction of the trough uniform, thereby creating an open-rack heat exchanger. The present invention aims to provide a foam extinguishing board for an open rack heat exchanger that can contribute to improving the performance of the exchanger.

[Means for solving the problem] The foam extinguishing board for the open rack heat exchanger according to the present invention is a foam board for supplying a heat transfer medium to the trough arranged along the upper part of the panel of the open rack heat exchanger. A foam extinguishing member is immersed in the heat transfer medium in the trough at the tip of the heat transfer medium supply pipe, and the foam extinguishing member includes a top plate disposed approximately parallel to the bottom of the trough and both longitudinal ends of the trough. It consists of a speakeasy weir installed on the side.
The gist of the sinkhole weir is that it projects in a tapered shape toward the flow direction of the heat transfer medium on the trough.

[Function] FIG. 1 is a perspective explanatory view showing a foam extinguishing board according to the present invention. In the foam extinguishing board 9 shown in FIG. 3, the hollow weir 9b was in the form of a flat plate, but in the foam extinguishing board 14 shown in FIG. It's getting better. That is, it protrudes in the flow directions A and B of the heat transfer medium, and has a so-called hexagonal horizontal cross section. Therefore, the supply pipe 8
Since the heat transfer medium flowing in through the weir 14b passes through the weir 14b and is largely dispersed in the directions of arrows 15 to 19 in FIG. 5, the stagnation portion 13 shown in FIG. 4 does not occur. When a trough was constructed using such a foam extinguishing plate 14 and the flow rate of the heat transfer medium in the longitudinal direction of the trough was measured as described below, it was found that compared to the case where the foam extinguishing plate 9 shown in FIG. It was found that the above flow rate could be made more uniform. Of course, these advantages are reflected in the performance of the open rack heat exchanger.

As the foam extinguishing board according to the present invention, one in which the undercover weir is shaped like an arc as shown in FIG. 6 can also be used. When such a foam extinguishing plate 20 is used, the heat transfer medium can be further dispersed in multiple directions due to the action of the arc-shaped submerged weir 21.

[Example] Fig. 8 is a cutaway perspective view of a main part of a trough 22 in which the foam extinguishing board 14 according to the present invention is used. The trough 22 includes a trough body 23 that extends horizontally along the panel 5, and a rectifying plate that is approximately the same length as the trough body and is disposed parallel to the side surface 23a of the trough body 23 while maintaining a gap between the sides 23a and 23a. 24, 24, the current plate 2 in the area surrounded by the current plate 24, 24;
4, 24, and the lower edges 24a, 24a of the rectifying plates 24, 24 are closely fixed to the bottom plate 2 of the trough body.
3b, and similarly the above-mentioned submerged weir 14b
The lower end edge 140b of also maintains a distance from the bottom plate 23b. Therefore, the seawater supplied from the supply pipe 8 passes through the weir 14b and the opening 25, passes through the non-contact part or the spaced part, flows over the side surface 23a of the trough main body, and descends the panel 5. .

These dynamics of the seawater, especially the movement of the trough 22 in the longitudinal direction, are the same as those described in the [Function] section, so the explanation thereof will be omitted, but the point is that the movement of the trough 22 in the longitudinal direction is It is possible to achieve uniformity of the seawater flow in the direction.
This is shown in Figure 9. Incidentally, when using the foam extinguishing board 9 shown in Figure 3, the seawater flow difference in the longitudinal direction was around 30%, but when using the foam extinguishing board 14 of the present invention, it decreased to about 10%. I was able to do it.

In the above embodiment, the trough body 23 and the rectifying plate 24
Although the lengths of the current plate 24 were almost the same, even if the current plate 24 is shortened, the function of the current plate will not be impaired. However, if it falls below a certain value, it will not be able to perform its original function as a current plate, so in view of this, the inventors of the present invention continued further studies to find the above-mentioned limit value. As a result, as shown in FIG. 10, it was found that if the length of the current plate 24 is 1/4 or more of the length of the trough body 23, its function as a current plate can be sufficiently effectively exhibited.

By the way, it was mentioned that marine organisms occur near the stagnation area 13 (FIG. 4). In the above embodiment, the stagnation part 13 etc. does not occur, so ideally the above marine organisms should not occur at all.
As a practical matter, it is inevitable that marine organisms will grow on the lower edge 24a of the current plate 24 (particularly the part separated from the foam extinguishing plate 14). The present inventors have used ultraviolet irradiation technology etc. to remove such marine organisms, but as mentioned above, the length of the rectifying plate 24 can be shortened to 1/4 of the trough body. This alone makes it easier to remove the marine organisms. Moreover, since the shadow area of the rectifying plate that occurs when irradiating ultraviolet rays can be reduced, it is also possible to contribute to the removal of marine organisms from this point of view.

As shown in FIGS. 11 and 12, a slide guide 26 is provided on the rectifying plate 24, and the foam extinguishing plate
If 4 is made to be able to slide horizontally, the flow can be optimally adjusted in consideration of the actual flow situation. Furthermore, in the above embodiment, the explanation has been made with the intention that the supply pipe 8 is fixed to the top plate 14a of the foam extinguishing board 14 with bolts, nuts, etc., but it is not necessarily necessary to do it this way. Separation part 2 where the top plate 14a can be opened and closed as shown in the figure
7 and the supply pipe is clamped between the separating parts 27, the supply pipe 8 can be freely removed through the opening/closing operation, and maintenance work such as cleaning inside the foam extinguishing board 14 can be done easily. This can be done even more smoothly. Furthermore, the above foam extinguishing board 1
4, a reflector plate 28 may be provided at the bottom of the supply pipe 8 or inside the foam extinguishing plate 14 for the purpose of converting the downward flow component of the supplied seawater into a horizontal flow component (FIG. 12). By making the top plate 14a openable and closable, the lower surface of the reflector 28 can be cleaned more effectively. Of course, the number of the reflecting plates may be one or more. It goes without saying that the circumstances described above also apply to the case where the foam extinguishing board shown in FIG. 6 is used.

[Effects of the invention] Since the present invention is constructed as described above, it can exhibit the following excellent effects.

(1) In addition to effectively demonstrating the original function of the foam extinguishing plate, it was also possible to equalize the flow rate of the heat transfer medium in the longitudinal direction of the trough.

(2) Therefore, it is possible to improve the functionality of the open rack heat exchanger.

(3) Since the so-called "stagnation area" can be reduced, the occurrence of marine organisms can be suppressed, and this can contribute to facilitating the maintenance work of foam extinguishing boards, troughs, etc.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a foam extinguishing board according to the present invention, Fig. 2 is a perspective view schematically showing an open rack heat exchanger, Fig. 3 is a perspective view of a conventional foam extinguishing board, and Fig. 4 is a conventional one. Explanatory diagram conceptually showing the flow situation of the heat transfer medium in the trough configured using the foam extinguishing plate, No. 5
The figure is an explanatory diagram corresponding to FIG. 4 when the foam extinguisher of the present invention is used, FIG. 6 is a perspective view showing another example of the foam extinguisher of the present invention, and FIG. 7 is a conventional foam extinguisher. A graph showing the error rate of the heat transfer medium flow rate in a trough constructed using a plate, FIG. 8 is a cutaway perspective view of the main part of a trough using the foam extinguishing board according to the present invention, and FIG. 9 is a graph showing the error rate of the heat transfer medium flow rate in a trough constructed using the present invention. Figure 10 is a graph corresponding to Figure 9 when the length of the current plate is set to 1/4 of the trough body, Figure 11 is a graph corresponding to Figure 7 when using a foam extinguishing board according to FIG. 12 is an explanatory plan view of a trough in which the present invention is used, and a cross-sectional explanatory view showing a state in which a reflecting plate is provided. 5...Panel, 6,22...Trough, 7...Open rack heat exchanger, 8...Supply pipe, 9,1
4,20... Foam eraser board, 14a... Top plate, 14b...
...Speaker weir.

Claims (1)

[Scope of utility model registration request] A foam extinguishing member that is immersed in the heat transfer medium in the trough at the tip of the heat transfer medium supply pipe that supplies the heat transfer medium to the trough arranged above the panel of the open rack heat exchanger. The foam extinguishing member is composed of a top plate disposed approximately parallel to the bottom surface of the trough, and a sink weir provided at both longitudinal ends of the trough, and the sink weir is oriented in the flow direction of the heat transfer medium on the trough. A foam extinguishing board for an open rack heat exchanger, which was once characterized by a tapered protrusion.