JPH0218459Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention consists of a large number of small-diameter heat transfer tubes arranged in a staggered or grid pattern inside a large-diameter outer shell to transmit the condensable gas refrigerant fed into the outer shell. This relates to a shell-type condenser that condenses by exchanging heat with a cooling refrigerant flowing in a heat tube.

FIG. 1 shows a cross section of a conventional shell-type condenser, and this conventional condenser has a large number of heat transfer tubes 3, 3, etc. each having a circular cross section arranged in parallel to each other in an outer shell 1. ing.

In this condenser, the condensable gas refrigerant fed into the outer shell 1 is condensed on the surface of a large number of heat transfer tubes 3, and as shown in FIG. do. Further, when the droplets d slide down on the outer surface of the heat transfer tube 3 due to gravity, the droplets combine with each other and grow, falling from the lower end of the heat transfer tube 3 as large droplets D.

In this way, condensate in the form of droplets or films adheres to the outer surface of the heat transfer tube 3, but this condensate is a factor that inhibits heat transfer between the heat transfer tube 3 and the condensable gas refrigerant G. Therefore, in order to increase the condensing capacity in the condenser, it is necessary to promote the separation of the condensed liquid from the surface of each heat transfer tube 3.

The flow condition of the condensate adhering to the heat exchanger tube 3 is
To explain with reference to the figure, where the pipe wall has a gentle slope, the condensate flows slowly, whereas where the pipe wall has a large slope, the flow rate increases. That is, condensed droplets d attached to the tube wall of the heat transfer tube
Gravity acts as shown by the symbol w in Fig. 2, and of this gravity w, the component force parallel to the pipe wall w ₁
becomes a force that moves the droplet d along the tube wall against the adhesive force and frictional force between the condensed droplet d and the tube wall. This component force w ₁ is expressed as w cos θ, and increases as the slope of the tube wall increases (where the angle θ between the tangent to the tube wall and the vertical line decreases), and therefore the falling velocity of the condensed droplet d increases. growing.

Further, the condensed droplets flowing down along the tube wall of the heat exchanger tube 3 gather on the lower circumferential surface 4 of the heat exchanger tube 3 and become attached as large aggregated droplets D, and the weight of the aggregated droplets D increases. When the collected droplets D grow until they overcome the adhesive force with the lower peripheral surface of the heat exchanger tube, the collected droplets D separate from the heat exchanger tube 3 and fall. In this case, if the contact area S of the collected droplets D on the lower circumferential surface of the heat exchanger tube is large, heat exchange between the heat exchanger tube 3 and the condensable gas refrigerant G will be hindered.
It is preferable that this tube liquid contact area S be as small as possible.

On the other hand, as described above, the condensed droplets that condense on the heat transfer tube and drop as droplets have an effect on the heat exchange effect between the heat transfer tube 3 and the condensable gas refrigerant G. In addition, in a shell type condenser in which a large number of heat exchanger tubes 3 are arranged in a staggered or grid pattern, the influence between the heat exchanger tubes cannot be ignored. In other words, if the arrangement of the heat exchanger tubes is set so that the upper heat exchanger tube and the lower heat exchanger tube are completely polymerized in the vertical direction, condensation occurs on the upper heat exchanger tube, forming large aggregated droplets. After growing, the droplets that separate from the upper heat exchanger tube 3 move downward while sequentially dropping onto the lower heat exchanger tube 3, so that the lower heat exchanger tube condenses on its own surface. The heat exchange effect is obstructed not only by the condensed droplets, but also by the droplets dripping from the upper stage. Therefore, in terms of improving the heat exchange effect between the heat exchanger tubes 3 and the condensable gas refrigerant G, droplets falling from the upper heat exchanger tubes 3 are dropped onto the lower heat exchanger tubes 3. It is better to suppress adhesion to the surface as much as possible.

The present invention promotes the flow of the condensed droplets d on the heat exchanger tube and reduces the contact area S of the collected droplets D on the lower peripheral surface of the heat exchanger tube, thereby promoting the separation of the condensed droplets from the heat exchanger tube 3. At the same time, by minimizing the dripping of condensed droplets from the upper heat exchanger tubes 3 to the lower heat exchanger tubes 3, the heat transfer between the heat exchanger tubes 3 and the condensable gas refrigerant G is inhibited by the condensed droplets. This was done with the aim of suppressing the heat exchanger tubes and improving the heat transfer coefficient between the heat exchanger tubes and the condensable gas refrigerant. They are arranged in a staggered or grid pattern so that they are lined up in the same row in both the horizontal and vertical directions, and the cooling refrigerant is allowed to flow through each of the heat transfer tubes, and the condensable gas refrigerant is allowed to flow through the outer shell, respectively. In the shell-type condenser, each of the heat exchanger tubes is formed into a flat cross-sectional shape having at least one sharp circumferential surface continuous in the tube axis direction, and each of the heat exchanger tubes is formed such that its major axis is relative to a vertical line. The drip line of the condensed liquid droplets dripping from the sharp peripheral surface of the upper heat exchanger tube is deviated in the horizontal direction with respect to the center line of the lower heat exchanger tube with the sharp peripheral surface facing downward. It is characterized by being arranged in a state in which the

Next, some preferred embodiments of the present invention will be explained with reference to the drawings below FIG. The cross-sectional shapes of usable flat heat exchanger tubes are shown.

The flat heat exchanger tube 3 shown in FIG. 3 has a circular cross section with sharp circumferential surfaces 3a, 3a at both ends in the longitudinal direction. It is installed in the outer shell 1 with l (corresponding to the long axis) inclined at an angle α with respect to the vertical line L.

The flat heat exchanger tube 3 shown in FIG. 4 has an oval cross-sectional shape, with the sharp circumferential surface 3a facing downward and the major axis l (i.e., the sharp circumferential surface 3a and the arcuate circumferential surface 3c opposite thereto). Among the straight lines connected, the longest one)
It is installed in the outer shell 1 with the frame tilted at an angle α with respect to the vertical line L.

The flat heat exchanger tube 3 shown in FIG. 5 has a teardrop-shaped cross-sectional shape, with the sharp peripheral surface 3a facing downward and the major axis l inclined at an angle α with respect to the vertical line L. It is installed inside the outer body 1 in the state of being

FIG. 3 shows the flow of condensate on the flat heat exchanger tube 3 when the sharp circumferential surface 3a faces downward and the major axis l is inclined with respect to the vertical line L. To explain this, since the heat exchanger tube 3 is flat and arranged with the sharp peripheral surface 3a facing downward, both side walls 3
The part b becomes nearly vertical, and the component force w ₁ (=wcosθ) required for the condensed droplet d attached to the side walls 3b to flow down along the wall surface becomes close to the weight w of the condensed droplet d (angle (because θ is small).

In addition, the collected droplets D attached to the sharp peripheral surface 3a on the lower side of the flat heat exchanger tube 3 have a contact area S with the wall surface of the heat exchanger tube.
Because of the narrowness of the tube, compared to the case of the circular tube shown in FIG.
The heat transfer inhibition during

Furthermore, in this case, since the center point of the sharp circumferential surface 3a is horizontally shifted from the vertical line L passing through the center of the heat exchanger tube 3, the aggregated droplets D that collect and grow on the sharp circumferential surface 3a and then drop. The drip line will be shifted from the vertical line L in the left-right direction. Therefore, even if the heat exchanger tubes 3, 3, etc. arranged in the vertical direction are arranged in the same line in the vertical direction, the heat exchanger tubes 3 will inevitably fall in line with the drip line from the heat exchanger tubes 3 on the upper stage. Since it is deviated in the left-right direction, the adhesion of the collected droplets D dropping from the upper heat exchanger tube 3 to the surface of the lower heat exchanger tube 3 is reduced as much as possible.

In Figures 2 and 3, the range indicated by the symbol Z indicates the length in the vertical direction within the range where the angle θ is smaller than 45°, but in the case of the circular heat exchanger tube 3 in Figure 2, this Z is the length of the heat exchanger tube Approximately for the height (diameter) Y of 3
0.71 times, in the case of oval heat exchanger tube 3 in Figure 3, this Z
is approximately 0.79 times the height Y of the heat exchanger tube 3 (when the shorter axis X:longer axis Y=1:1.7 and the inclination angle α=30°).

In this way, the circular heat exchanger tube 3 shown in FIG. 3 has a larger ratio of the length of the wall surface through which the condensed droplets d can easily flow down than the circular heat exchanger tube 3 shown in FIG. Becomes good.

Such liquid drainage promotion effect is the same for the oval heat exchanger tube shown in FIG. 4 and the teardrop-shaped heat exchanger tube shown in FIG. 5.

6 and 7 show some examples of arrangement of the flat heat exchanger tubes 3 within the outer shell 1. FIG. In each of these drawings, the circular heat exchanger tube shown in Figure 3 is used, but instead of the circular heat exchanger tube, an oval heat exchanger tube as shown in Figure 4 or a teardrop-shaped heat exchanger tube as shown in Figure 5 may be used. Use is optional.

In the condenser shown in FIG.
is inclined by an appropriate angle α with respect to the vertical line, while the direction of the inclination is opposite to that of the heat exchanger tubes in the upper stage and the heat exchanger tubes in the immediately lower stage. or,
The upper heat exchanger tube 3 is arranged so as to be located between two adjacent heat exchanger tubes 3, 3 immediately below, and is arranged on the same vertical line as the heat exchanger tube 3 two steps below. In addition, there is a slight interval t between the vertical line V common to the odd-numbered heat exchanger tubes 3, 3... on the same vertical line and the vertical line V' common to the even-numbered heat exchanger tubes 3, 3... It is like that. Therefore, when a cooling refrigerant such as water is allowed to flow through the heat transfer tubes 3 and a condensable gas refrigerant is allowed to flow through the outer shell 1, the collected droplets D dropping from the upper heat transfer tubes 3 are distributed as much as possible to the lower heat transfer tubes 3. You can avoid contact with. Moreover, the heat exchanger tubes 3 of each stage are arranged so as to be lined up on the same horizontal line.

In the condenser shown in Fig. 7, each inertia circular heat exchanger tube 3, 3...
are arranged in a grid pattern, with their major diameter lines l inclined in the same direction by an angle α with respect to the vertical line L, and the heat exchanger tubes in each row of each stage are on the same vertical line and the same horizontal line, respectively. It is placed. Therefore, in this case as well, the lower heat exchanger tube 3 is displaced horizontally with respect to the drip line of the upper heat exchanger tube 3, and the collected droplets D fall down the side ends of the heat exchanger tubes 3 and the collected liquid drops. Contact between the droplet D and the heat transfer tube 3 is prevented as much as possible,
In this respect, heat transfer performance can be improved.

In carrying out the present invention, flat heat exchanger tubes may be used as they are, but it is also possible to attach fins to the flat heat exchanger tubes, or to provide them with loaf-ins, or to use a method common to many heat exchanger tubes. The heat transfer effect can also be improved by attaching plate-like fins.

Next, to explain the effects of the present invention, the present invention has a zigzag or go board structure in which a large number of heat transfer tubes are placed inside the outer shell, with their respective tube axes being horizontal, and in which they are lined up in the same row in both the horizontal and vertical directions. In a shell-type condenser in which a large number of heat transfer tubes are arranged in a mesh shape, and a cooling refrigerant is allowed to flow in each of the heat transfer tubes and a condensable gas refrigerant is allowed to flow in the outer shell, each of the heat transfer tubes has at least one sharp peripheral surface. In addition to forming the tube into a flat cross-sectional shape that is continuous in the tube axis direction,
Each of the heat transfer tubes is arranged such that its major axis is inclined with respect to the vertical line and the sharp peripheral surface faces downward, and the drip line of condensed liquid droplets dripping from the sharp peripheral surface of the heat transfer tube on the upper stage is set to the lower stage. The heat exchanger tube is characterized in that it is disposed horizontally offset from the center line of the heat exchanger tube.

Therefore, according to the shell-type condenser of the present invention, (1) a heat exchanger tube having at least one sharp peripheral surface is arranged with its major axis inclined with respect to the vertical line and with its sharp peripheral surface facing downward; (2) The individual factors of each heat exchanger tube are that it is possible to promote the flow of condensed droplets on the heat exchanger tube and to narrow the contact area of the collected droplets on the lower peripheral surface of the heat exchanger tube. Since the lower heat exchanger tubes are arranged horizontally offset from the drip line of the condensed droplets dripping from the upper heat exchanger tubes, the condensed droplets flowing down on the surface of each heat exchanger tube The heat transfer between the heat exchanger tubes and the gas refrigerant is reduced due to the synergistic effect of The effect is that the transmission rate is further improved.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional shell-type condenser;
The figure is a cross-sectional view of a heat exchanger tube used in the condenser of Figure 1, and Figures 3, 4, and 5 are cross-sectional views of flat heat exchanger tubes that can be used in the condenser of the embodiment of the present invention. , FIG. 6, and FIG. 7 are explanatory views of the arrangement of the flat heat exchanger tubes shown in FIG. 3, respectively. 1... Outer shell, 3... Heat exchanger tube, 3a... Sharp peripheral surface.

Claims (1)

[Scope of utility model registration request] Inside the outer shell 1, a large number of heat exchanger tubes 3 are arranged in a zigzag or checkerboard pattern such that their tube axes are horizontal and are lined up in the same row in both the horizontal and vertical directions. In the shell type condenser, in which a cooling refrigerant is allowed to flow in the outer shell 1, and a condensable gas refrigerant is allowed to flow in the outer shell 1, each of the heat transfer tubes 3 has at least one sharp peripheral surface 3a continuous in the tube axial direction. At the same time, each heat exchanger tube 3 is formed into a flat cross-sectional shape with its major axis inclined with respect to the vertical line, and the sharp circumferential surface 3a is directed downward, and the sharp circumferential surface of the upper heat transfer tube 3 is formed. 3a
A shell-type condenser characterized in that the drip line of condensed liquid droplets dripping from the lower heat transfer tube 3 is disposed horizontally with respect to the center line of the heat transfer tube 3.