JP2000097590A - Plate-type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat transfer performance and restrain the adhesion as well as the accumulation of scale by improving the sectional configuration of a heat transfer surface. SOLUTION: The angle θ1 of an ascending wall 4a of a ridge 4, formed on the heat transfer surface of a heat transfer plate 1, is formed so as to be different from the angle θ2 of a descending wall 4b to form the heat transfer surface so as to have an asymmetric corrugated sectional configuration. On the other hand, the angle θ2 of the descending wall 4b of the ridge 4 is formed so as to be larger than the angle θ1 of the ascending wall 4a in order to mitigate the inclination with respect to the stream of liquid at the downstream of the crest 4c of the ridge 4, formed on the heat transfer surface of the heat transfer plate 1, and bring more amount of the flow of liquid to the downstream of the crest 4c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate heat exchanger using a heat transfer plate having a heat transfer surface having a corrugated cross section, and more particularly to a cross section of a heat transfer surface.

[0002]

2. Description of the Related Art In general, a plate heat exchanger forms a plurality of fluid passages between heat transfer plates by stacking a plurality of heat transfer plates alternately upside down via a gasket. Different fluids to be heat-exchanged alternately flow through the plurality of fluid passages, and heat exchange is performed between the two fluids via the plate.

In such a plate heat exchanger,
For example, as shown in FIG. 4, a heat transfer plate 11 is used. This heat transfer plate 11 is formed in a rectangular shape with a material having good heat conductivity, has a heat transfer surface 12 at a central portion, and is provided with passage holes 13 at four corners serving as inlets and outlets of fluid. . The heat transfer surface 12 is formed in a wavy cross-sectional shape in which herringbone-shaped ridges 14 inclined toward both sides from the center line in the plate longitudinal direction are continuously formed in a V-shape or a mountain shape at equal intervals. The ridge 14 is composed of an upper wall 14a and a lower wall 14b, and the angle θ ₁ of the upper wall 14a and the angle θ _{2 of the} lower wall 14b are formed at the same angle, so that the heat transfer surface 12 has a symmetrical waveform cross-sectional shape. (See FIGS. 5 and 6). By alternately stacking the heat transfer plates 11 upside down, as shown in FIGS. 5 and 6, fluid passages A and B for different fluids to be heat-exchanged between the heat transfer plates 11 are formed. Are alternately formed.

[0004]

[SUMMARY OF THE INVENTION In conventional plate heat exchanger described above, the wall 14a of the upper and lower facing ribbed 14 formed on the heat transfer surface 12 of the heat transfer plate 11, 14b of the angle theta _1, theta ₂ Have the same angle and the heat transfer surface 12 is formed in a symmetrical wavy cross-sectional shape.
Fluid passages A and B having the same cross-sectional shape are formed between each other. Accordingly, when the conventional plate heat exchanger is used as a condenser, that is, the condensed fluid (for example, steam) flows through the fluid passage A and the refrigerant (for example, cooling water) flows through the fluid passage B, and heat is generated. In the case of replacement, as shown in FIG. 5, the condensed liquid a in the fluid passage A drops in the direction of gravity, and the ridges 14 formed on the heat transfer surface 12 of the heat transfer plate 11.
Stays as droplets on the surface of the lower wall 14b, and then flows down as large droplets.
b flows along the direction of inclination of the ridge 14, so that a condensed liquid film is formed on the surface of the lower wall 14b, thereby deteriorating the condensation performance. Therefore, a large heat transfer area is required for the condenser, and a large number of heat transfer plates 11 are required, so that there is a problem that the cost is increased and the size of the condenser is increased.

When a conventional plate-type heat exchanger is used for heat exchange of two liquids containing a large amount of scale components without phase change, as shown in FIG. A stagnation region b of the flow is generated downstream of the convex top portion 14c of the formed ridge 14, and the heat transfer performance is reduced. In addition, in the stagnation region b, the problem of adhesion and deposition of scale is remarkable, which causes a decrease in heat transfer performance and requires frequent cleaning.

The present invention has been proposed to solve the above-mentioned problems, and has as its object to improve heat transfer performance and suppress the adhesion and deposition of scale.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a heat transfer plate having a heat transfer surface in which the upper and lower walls facing the ridge formed on the heat transfer surface have different angles and the heat transfer surface is asymmetric. Provided is a plate heat exchanger having a corrugated cross section.

[0008]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG.

FIG. 1 shows a heat transfer plate 1 in a plate heat exchanger according to the present invention. This heat transfer plate 1 is formed in a rectangular shape with a material having good heat conductivity, has a heat transfer surface 2 at the center, and has passage holes 3 at four corners serving as fluid inlets and outlets, as in the conventional case. Has been drilled. Heat transfer surface 2
Is formed in a corrugated cross-sectional shape in which a herringbone-shaped ridge 4 inclined toward both sides from the center line in the plate longitudinal direction is formed (see FIGS. 2 and 3). The ridge 4 is composed of an upper wall 4a and a lower wall 4b. The angle θ ₁ of the upper wall 4a and the angle θ _{2 of the} lower wall 4b are different from each other so that one is larger and the other is smaller than the conventional waveform cross-sectional shape. For example, when used as a condenser, as shown in FIG. 2, the heat transfer surface 2 is formed with θ ₁ <θ ₂ ), and the heat transfer surface 2 is formed in an asymmetric corrugated cross section. Then, the heat transfer plates 1 are alternately turned upside down and stacked so that fluid passages A and B for different fluids to be heat-exchanged between the heat transfer plates 1 are alternately formed. I have.

In the plate heat exchanger of the present invention,
The angle θ ₁ of the upper wall 4a of the ridge 4 formed on the heat transfer surface 2 of the heat transfer plate 1 and the angle θ _{2 of the} lower wall 4b are formed at different angles, so that the heat transfer surface 2 is formed into an asymmetric corrugated cross-sectional shape. Therefore, fluid passages A and B having different characteristics with respect to the flow direction are formed (see FIGS. 2 and 3).

Accordingly, when the plate heat exchanger of the present invention is used as a condenser, as shown in FIG. 2, the angle θ ₁ of the upper wall 4a of the ridge 4 formed on the heat transfer surface 2 of the heat transfer plate ₁ By increasing the angle θ _{2 of the} lower wall 4b, the condensed liquid a immediately flows down the lower wall 4a, so that a condensed liquid film does not form on the surface of the lower wall 4a, thereby improving the condensing performance.

When the plate heat exchanger of the present invention is used for heat exchange of two liquids without phase change, as shown in FIG. 3, the ridge formed on the heat transfer surface 2 of the heat transfer plate 1 is used. Downstream of the convex apex 4c of 4, the wall 4b has a gentle inclination with respect to the flow of the liquid, so that the stagnation of the flow is reduced.
The inclination of the wall 4a on the side facing the flow is higher than that of the conventional one, and the flow of the liquid is more increased downstream of the convex portion 4c, so that the heat transfer performance is improved and the adhesion and deposition of scale are suppressed. can do.

If the angle θ ₁ of the upper wall 4a and the angle θ _{2 of the} lower wall 4b of the ridge 4 formed on the heat transfer surface 2 of the heat transfer plate 1 are formed at the same angle and larger than the conventional corrugated cross section,
The same effects as those of the embodiment shown in FIGS. 2 and 3 can be obtained. However, in this case, the plate elongation is reduced, the heat transfer area obtained from the same material is reduced, and the cost is significantly increased. Cause problems. In addition, ridge 4
And the opening angle of the ridges 4 becomes large, causing a problem that the pressure resistance of the heat transfer plate 1 is significantly reduced.

On the other hand, the ridges 4 formed on the heat transfer surface 2 of the heat transfer plate 1 like the plate heat exchanger of the present invention.
The angle θ ₁ of the upper wall 4a and the angle θ _{2 of the} lower wall 4b are formed at different angles so that one is larger and the other is smaller than the conventional corrugated cross section, so that the heat transfer surface 2 is formed in an asymmetric corrugated cross sectional shape. Then, a decrease in the plate elongation rate and an increase in the pitch of the ridges 4 can be suppressed by the same or slight changes as the conventional corrugated cross-sectional shape. Therefore, in the plate heat exchanger of the present invention, the heat transfer performance is improved, the scale is prevented from adhering and accumulating, and the cost and the pressure resistance are prevented from being reduced.

Although the preferred embodiment for carrying out the present invention has been described above, the present invention is not limited to this embodiment, and can be modified within the scope of the present invention. For example, as an embodiment of the present invention, the heat transfer surface 2
Although the description has been given of the case where the wavy cross-sectional shape is formed by forming the herringbone-shaped ridges 4 inclined toward both sides from the plate longitudinal center line, the plate longitudinal center line may be displaced in addition to this. It may be of a corrugated shape.

In the embodiment of the present invention, the same heat transfer plate 1 is used as a method for obtaining the fluid passages A and B of the fluid.
Although the heat transfer plates 11 are alternately turned upside down, the heat transfer plates 11 may be turned upside down and combined, or two different heat transfer plates may be combined.

[0017]

As described above, according to the plate heat exchanger of the present invention, the heat transfer plate 1 is formed by forming the angles of the upper and lower walls facing the ridge formed on the heat transfer surface at different angles. By forming the surface into an asymmetrical wavy section,
It is possible to improve the heat transfer performance by preventing the occurrence of liquid film and flow stagnation, and to suppress the adhesion and deposition of scale.

[Brief description of the drawings]

FIG. 1 is a plan view of a heat transfer plate in a plate heat exchanger of the present invention.

FIG. 2 is a sectional view of the heat transfer plate of FIG.
It is a principal part sectional view in a line, and is the case where it is used as a condenser.

FIG. 3 is a cross-sectional view of the heat transfer plate of FIG.
FIG. 4 is a cross-sectional view of a main part in a line, in which the liquid is used as a heat exchanger for liquids.

FIG. 4 is a plan view of a heat transfer plate in a conventional plate heat exchanger.

FIG. 5 is a cross-sectional view of the heat transfer plate of FIG.
It is a principal part sectional view in a line, and is the case where it is used as a condenser.

FIG. 6 is a cross-sectional view of the heat transfer plate of FIG.
FIG. 4 is a cross-sectional view of a main part in a line, in which the liquid is used as a heat exchanger for liquids.

[Explanation of symbols]

Reference Signs List 1 heat transfer plate 2 heat transfer surface 3 passage hole 4 ridge 4a ridge upper wall 4b ridge lower wall 4c ridge convex top θ ₁ ridge upper wall angle θ ₂ ridge lower wall angle

Claims (3)

[Claims] 1. A plate heat exchanger in which heat transfer plates having a heat transfer surface having a corrugated cross-sectional shape with ridges are stacked, wherein upper and lower sides of the ridges formed on the heat transfer surface of the heat transfer plate are opposed to each other. Characterized in that the walls of the plate have different angles and the heat transfer surface has an asymmetric corrugated cross-sectional shape. 2. The condenser according to claim 1, wherein a lower wall angle of the ridge formed on the heat transfer surface of the heat transfer plate in the fluid passage on a condensed fluid side is larger than an upper wall angle. Item 4. A plate heat exchanger according to item 1. 3. The plate heat exchanger according to claim 1, wherein the plate heat exchanger is used as a two-fluid heat exchanger without phase change.