JP2000266489A - Plate type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate type heat exchanger which can make a fluid to evenly flow on the surfaces of plates without causing deviations and has a high heat- exchanging efficiency. SOLUTION: A plate type heat exchanger is constituted by arranging a plurality of heat-exchanging elements 2, each of which is constituted by putting two facing plates 1 and 1' together in one set by placing the peripheral edges 7 of the plates 1 upon another, and uses the sealed internal space of the plates 1 and 1 as the flow passage of a first fluid and the external surfaces of the plates 1 and 1' as the flow passage of a second fluid, in such a way that the heat transferring surfaces of the plates 1 and 1' are faced oppositely to each other at prescribed intervals. The heat transferring surface of each plate 1 and 1' is formed in such a corrugated shape that linear recessed sections 3 and projecting sections 4 are alternately arranged and, when the two plates 1 and 1' are put together, at least parts of the recessed sections 3 of the plates 1 and 1' come into contact with each other together with the peripheral edge sections. In addition, the linear corrugated shapes of the plates 1 and 1' shape are inclined by 0-30 deg. from the vertical direction. It is also possible to form projections in the recessed sections 3 and recesses in the projecting sections 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate type heat exchanger in which plates are stacked and a fluid flows between the plates to exchange heat, and more particularly to an evaporator of a refrigerator using a low-pressure refrigerant, a low-temperature regenerator, and the like. The present invention relates to a plate heat exchanger suitable for a case where at least one of the fluids is low-pressure steam such as a condenser (or a case where phase change causes vaporization or liquefaction from vapor).

[0002]

2. Description of the Related Art In a plate heat exchanger, when two plates are superimposed on each other, the intersection (or contact portion) between the recesses is soldered to maintain the strength of the plates. In an apparatus such as an absorber, an evaporator, or a regenerator, in which a liquid film is formed on a heat transfer surface to transfer heat, the liquid is preferably spread over the entire heat transfer surface and wetted.
For this reason, sand blast is applied so that the plate surface has hydrophilicity. When used as a condenser, hydrophilicity is not required and water repellency may be used. Usually, in a plate heat exchanger, the liquid film on the plate surface flows from top to bottom, while the internal fluid is generally supplied from below and out from above.
In this way, when the internal fluid flows vertically, the unevenness on the plate surface is nearly horizontal, and in the case of an inclined wave, the liquid flows along the unevenness, and the distribution of the liquid becomes uneven, The surface dries out. Further, if the contact portions are horizontal, if the contact portions between the concave portions are soldered, the flow will be hindered. In addition, there is also a problem that the liquid is biased when the refrigerator is installed at a slight inclination.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides a plate having a high heat exchange efficiency in which a fluid can be evenly and uniformly flowed on a plate surface without causing unevenness. It is an object to provide a heat exchanger of the type.

[0004]

In order to solve the above-mentioned problems, according to the present invention, a pair of plates having irregularities facing each other is set as a set and the peripheral edges are overlapped to form a sealed space inside the two plates. Is a passage for the first fluid, the plate surface is vertical, and the second fluid flows down along the outer surface of the plate to exchange heat between the first fluid and the second fluid. As opposed to each other, in a plate heat exchanger in which a plurality of plates are arranged with a predetermined gap therebetween, the shape of the heat transfer surface of the plate is a wavy shape in which concave portions and convex portions alternately form a straight line, When two plates are overlapped, the concave portion of each plate and the concave portion are at least partially in contact with the peripheral portion, and the linear waveform shape has an inclination of 0 to 30 ° as viewed from the vertical. It is. In the plate heat exchanger, the concave and convex portions of the plate can be provided with projections in the concave portions and concave portions in the convex portions at predetermined intervals.

[0005]

Next, the present invention will be described in detail.
In the plate used in the present invention, two plates having irregularities are overlapped so as to form a space inside, and when the communication pipes (fluid ports) of the peripheral edge and the openings at both ends are simply overlapped, the plate is light over the entire circumference. When a contact is made (line contact) and a force is applied in the overlapping direction, the shape of the contact portion changes to form a surface contact. A shape suitable for sealing the periphery by (phrasing) can be used.
That is, in the case of brazing, in the case of brazing, in order to bring the plates into close contact with each other, brazing is performed while applying a force, but when this force is applied, the periphery becomes parallel, and the irregularities of the plate further contact. It is preferred.

[0006] When the two plates as described above are overlapped while the brazing material is placed (painted) on the portion to be contacted, a fluid flow path is formed between the spaces from the openings formed at both ends of the plate. Having a heat exchange element. The unevenness of the plate of the present invention can be formed as a wavy pattern extending in a predetermined direction, and the shape of the heat transfer surface of the plate is a waveform shape in which concave portions and convex portions alternately form a straight line, and a linear waveform is formed. The shape has an inclination of 0 to 30 ° when viewed from the vertical.
As described above, by setting the inclination within 30 °, the liquid flowing down the plate surface flows without causing unevenness. In addition, the concave / convex portions may be provided with projections in the concave portions and dents in the convex portions at predetermined intervals.

[0007] In the plate heat exchanger of the present invention, the same fluid may be all passed through the internal flow paths of the plurality of heat exchange elements, or a separate fluid may be alternately passed through each of the heat exchange elements. it can. When the same fluid is passed, the same fluid can be passed through the internal flow path of the heat exchange element by connecting all the openings at both ends of the plate of the heat exchange element. When passing through, connect the openings at both ends of the plate of every other heat exchange element with a communication pipe,
Alternately different fluids may be passed. Providing a swivel in one of the openings and the communication pipes at both ends of the plate facilitates positioning by fitting the openings when overlapping. Thus, the two-dimensional positioning of the plates is naturally performed only by overlapping the plates, thereby simplifying the manufacturing process. Also, the flow of the second fluid to the outer surface of the plate of the heat exchange element can be performed by disposing a liquid distributor on the upper surface of the element, and the liquid distributor is formed in a gutter shape parallel to the plate surface. An orifice hole is provided on the side surface for flowing down toward the plate surface.

In the heat exchange element of the present invention, the fluid flows on the outer surface and exchanges heat with the internal fluid via the heat transfer surface of the plate, so that the fluid flowing on the outer surface is applied to the heat transfer surface. It is necessary to improve the wettability so that there is no spread and no dry surface. Therefore, the plate constituting the heat transfer surface of the heat exchange element is made of stainless steel, and on its outer surface, a porous layer electrolytically dissolved, a diffusion layer of chromium oxide treated with a molten salt bath of chromium, or a large number of small It is good to provide a dent or make it satin-like. In order to provide a large number of small depressions on the outer surface, by providing a depression so as to transfer a large number of small protrusions on the mold surface during molding of the plate,
In addition, in order to form a matte surface, a material whose surface is already matte, for example, a stainless steel material whose surface is formed in a matte shape with a roller at the time of manufacturing a thin plate, or the surface is formed by electric discharge machining It is preferable that the electric discharge machining is performed in water, and the electric discharge machining is performed when manufacturing the plate heat exchanger after forming the plate, even when performing the thin plate (material). Is also good. In the case of a raw material, the electrode shape may be made flat, and a pulse current may be applied while moving the electrode or while moving the thin plate, so that the electrode shape can be simplified.

Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 3 are configuration diagrams of a heat exchange element of the plate heat exchanger of the present invention, in which (a) is a front view, (b) is a plan view, and FIG. 2 (c) is AA. FIG. 3D is an enlarged cross-sectional view, and FIG. In the figure, 1 and 1 'are plates, 2 is a heat exchange element, 3 is a concave portion, 4 is a convex portion, 5 is a concave protrusion, 6 is a concave portion, 7 is a peripheral portion, 8 is an opening, and 9 is an opening rising. Reference numeral 10 denotes a liquid distributor, and 11 denotes an orifice hole.

FIG. 1 shows the vertical direction of the wave of the concave portion 3 and the convex portion 4 of the surface shape of the plate 1, and FIG.
It has an inclination of 0 ° or less. In addition, FIG.
Although the inclination is in the direction of the mountain, the inclination may be in only one direction, or may be a multi-angle configuration. As described above, by setting the inclination in the vertical direction to 30 ° or less, the flow in the downward direction can be increased, and the bias in the lateral direction can be avoided. When the liquid distributor 10 is installed on the upper part, the orifice hole 11 of the liquid distributor is provided so as to spray the liquid toward each of the concaves and convexes 3 and, first, the liquid is distributed to each groove. Is good. In addition, even if it injects to the convex part 4 and divides it into two there, it does not matter. Also, within 30 ° from the vertical direction, even if inclined, the flow in the downward direction is strong, flows over the unevenness and flows downward, and there is not much deviation.

FIG. 2 shows that dents 6 are provided at predetermined intervals in the wave projections 4 and projections 5 are provided at predetermined intervals in the wave depressions 3 to strongly disturb the flow of the internal fluid and to reduce heat transfer. Can be better. In addition, the liquid film side can also prevent the downward flow from becoming too strong, slightly increase the flow time, improve the mixing of the liquid in the liquid film, and improve the heat transfer. It is to be noted that the dent 6 and the protrusion 5 as shown in FIG. 2 may be provided in the wave portion inclined as shown in FIG. The plate heat exchanger of the present invention can be used as an absorber, an evaporator, a regenerator, and a condenser of an absorption refrigerator, and can be integrally formed by alternately changing a fluid passing through the inside and the outside of the heat exchange element. The plate heat exchanger can be used as an absorption / evaporator or a regeneration / condenser of an absorption refrigerator.

[0012]

As described above, according to the present invention,
By making the waveform of the unevenness of the plate surface have a vertical inclination of 30 ° or less, the heat exchange efficiency of the plate heat exchanger is improved, and the absorber of the absorption refrigerator, the evaporator,
It can be suitably used for regenerators and condensers.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a heat exchange element used in the present invention, wherein (a)
Front view, (b) Plan view.

FIG. 2 is a configuration diagram of another heat exchange element used in the present invention,
(A) Front view, (b) Plan view, (c) AA cross section enlarged view, (d) BB cross section enlarged view.

FIG. 3 is a configuration diagram of another heat exchange element used in the present invention,
(A) Front view, (b) Plan view.

[Explanation of symbols]

1, 1 ': plate, 2: heat exchange element, 3: corrugated recess,
4: Wave-shaped convex portion, 5: protrusion, 6: dent, 7: peripheral portion,
8: Opening part, 9: Opening rising part, 10: Liquid distributor, 1
1: Orifice hole

Claims (2)

[Claims] 1. A pair of plates having irregularities facing each other are set as a set, and their peripheral edges are overlapped. A sealed space inside the two plates is used as a first fluid passage, the plate surface is made vertical, and A plate in which a plurality of heat exchange elements for causing the second fluid to flow down along the outer surface and exchanging heat between the first fluid and the second fluid are arranged with a predetermined gap therebetween so that the heat transfer surfaces face each other. In the heat exchanger,
The shape of the heat transfer surface of the plate is a corrugated shape in which the concave portions and the convex portions alternately form a straight line. While part contact, the linear waveform shape,
A plate-type heat exchanger having an inclination of 0 to 30 ° as viewed from the vertical. 2. The plate-type heat exchanger according to claim 1, wherein the concave and convex portions of the plate are provided with projections in concave portions and dents in convex portions at predetermined intervals.