JP3969556B2 - Plate heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plate heat exchanger in which plates are stacked and two fluids are alternately flowed between the plates to exchange heat, and in particular, an evaporator, a low temperature regenerator, and a condenser of a refrigerator using a low-pressure refrigerant. Furthermore, the present invention relates to a plate heat exchanger that is suitable when at least one of the fluids is low-pressure steam (or vaporized by phase change or liquefied from steam).
[0002]
[Prior art]
In general, unless the vapor velocity at the evaporator outlet or the vapor velocity at the absorber inlet is suppressed to about 50 m / s or less, the flow resistance increases and the refrigeration function decreases.
Conventionally, as a plate heat exchanger, as shown in FIG. 5, an absorber element 2 and an evaporator element 2 ′ are arranged alternately with the same plate surface facing each other. In this case, the size of the steam passage with respect to the surface of the plate 1 is plate height × plate width, and the inter-plate gap is not limited by the steam flow velocity, and can be made compact.
In the heat exchanger of the type as shown in Fig. 5, it is necessary to manufacture one heat exchange element combining two plates one by one and attach it to the chilled water header and the chilled water header one by one. In addition, the shape of the absorber and the evaporator is different, and the types of parts are increased.
[0003]
Further, for example, when the absorber element and the evaporator element are alternately arranged, the absorbing solution 11 and the refrigerant liquid 12 are simultaneously supplied to the top of the plate surface in the gap between the two elements, so that the droplets are scattered and absorbed. When the solution enters the refrigerant, the refrigerant becomes dirty, the boiling point rises, the evaporation temperature rises, the performance as a refrigerator deteriorates, and the amount of solution on the heat transfer surface decreases, making it difficult to get wet. There is.
On the other hand, when the refrigerant liquid scatters as droplets and enters the absorber side, the solution concentration decreases, the absorption capacity decreases, and the performance as a refrigerator deteriorates. In addition, since the refrigerant liquid does not evaporate and jumps out as a liquid, the original refrigeration effect is not exhibited, the efficiency is reduced, and the amount of the refrigerant liquid on the heat transfer surface is reduced, making it difficult to wet. is there.
[0004]
[Problems to be solved by the invention]
In view of the above-described conventional technology, the present invention provides a plate heat exchanger that has high heat exchange efficiency because liquid does not scatter and drops on the plate on the average when the liquid is supplied between the heat exchange elements. It is an issue to provide.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the present invention, in a plate heat exchanger for simultaneously exchanging two sets of fluids each having a different temperature, two plates facing each other are set as one set, A heat exchange element (A) having a hermetically sealed space as a first fluid passage, a plate surface as a heat transfer surface, and a fluid flowing along the outer surface of the plate as a second fluid, and a pair of two plates facing each other A heat exchange element (B) in which the sealed space inside the two sheets serves as a third fluid passage, the plate surface serves as a heat transfer surface, and the fluid flowing along the outer surface of the plate serves as a fourth fluid. The heat exchange elements (A) and (B) are arranged alternately with a predetermined gap so that the plate surfaces face each other, and a liquid distributor is provided in the gap. , Provided in the liquid distributor From each hole to the surface top of the heat exchange elements (A) and (B) is obtained by and score the flow of the second fluid and the fourth fluid.
[0006]
In the plate heat exchanger, as the liquid distributor, a tub having an orifice hole on the side surface can be used, or a plate surface can be used as the side surface of the tub in a bowl shape.
On the plate surfaces of the heat exchange elements (A) and (B), there are communication pipes that separately communicate the inner spaces of the heat exchange elements (A) and the inner spaces of the heat exchange elements (B). It is good that it is formed.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail.
When the plate used in the present invention is overlapped so as to form a space inside the two plates having uneven portions, and the communication pipes (fluid inlets and outlets) at the peripheral edge and the openings at both ends are simply overlapped, the entire circumference is covered. When lightly touching (contacting line) and applying force in the overlapping direction, the shape of the contact part changes to surface contact, and force is applied and the contact surface increases until the unevenness comes into contact. The thing of a suitable shape can be used for sealing a peripheral edge by phrasing.
That is, 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 peripheral portion becomes parallel and the unevenness of the plate is in contact with the plate. This is preferable.
[0008]
When the two plates as described above are overlapped while placing (waxing) the brazing material on the part to be contacted, heat exchange having a fluid flow path between the openings from the openings formed at both ends of the plate A vessel is constructed.
In the present invention, in addition to brazing (phrasing), a case in which a gasket is inserted therebetween and a force is applied from the outside, or a case of sealing by welding is included.
The unevenness of the plate of the present invention can be formed as a wavy pattern extending in a predetermined direction, and a complicated flow path that is two-dimensionally bent can be formed with a relatively simple configuration.
In addition, since the opening communication pipes at both ends of the plate are inserted between the heat exchange element of the same flow path and the heat exchange element of other flow paths and the scattering prevention means, the elements and the prevention means can be inserted. The length of the communication pipe is such that a space can be formed on the outer surface of the plate, and the communication pipe can be provided on one side of both ends of the plate. It can be inserted and brazed at once while applying force in the furnace.
[0009]
By providing an opening in one of the opening communicating pipes at both ends of the plate, positioning can be simplified by fitting the opening when overlapping. Thereby, since the two-dimensional positioning of the plates is naturally performed only by overlapping the plates, the manufacturing process is simplified.
The liquid distributor provided on the upper surface of the heat exchange element of the present invention is provided in a bowl shape in parallel with the plate surface, and has orifice holes on the side surface for flowing the liquid toward the plate surface. The liquid distributor may use a plate surface as one side surface of the bottle. Thereby, scattering of the liquid at the time of supplying the fluid to the plate surface can be prevented, and the fluid can flow evenly on the plate surface evenly.
Further, a splash prevention means can be inserted in the lower part of the liquid distributor between the heat exchange elements (A) and (B) of the present invention, thereby scattering the fluid supplied onto the plate surface. Can be prevented more. The scattering prevention means may be a baffle plate composed of two plates so that the respective scattered liquids are returned to the heat transfer surface of the scattering source.
[0010]
In the heat exchange element of the present invention, the fluid flows on the outer surface and exchanges heat with the inner fluid via the heat transfer surface of the plate. Therefore, the fluid flowing on the outer surface spreads on the heat transfer surface and is dry. It is necessary to improve wettability so that there is no 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 dissolved electrolytically, a diffusion layer of chromium oxide treated with a molten salt bath of chromium or a large number of small It is better to provide a dent or a satin finish.
In order to provide a large number of small depressions on the outer surface, by forming depressions so as to transfer a large number of small protrusions on the mold surface during the molding of the plate, It is possible to use a material that has already been satin-finished, for example, a surface of a stainless steel material that has been formed into a satin-finished surface with a roller during the production of a thin plate, or the surface can be formed by electrical discharge machining. The electric discharge machining is preferably performed when the plate is a thin plate (raw material) or when the plate heat exchanger is manufactured after the plate is formed. When the material is used, the electrode shape may be set to a plane, and a pulse current may be applied while moving the electrode or moving the thin plate, and the electrode shape can be simplified.
[0011]
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a plate heat exchanger according to the present invention, which is formed by alternately connecting three heat exchange elements 2 and 2 ′.
The heat exchange element 2 is made by adhering two plates 1 and fixing them by welding or brazing between the contact portion of the concavo-convex pattern and the peripheral portion 6.
A baffle plate 3 is provided between the heat exchange elements 2 and 2 'to prevent scattering of fluid flowing on the plate surface, and a liquid distributor 4 is installed above the heat exchange elements 2 and 2'. The fluid flows from the orifice hole 5 of the liquid distributor along the heat transfer surface of the plate surface.
[0012]
Thus, if the liquid distributor is installed so as to be in contact with the heat transfer surface of the plate surface and the baffle plate is placed, the second fluid 11 or the fourth fluid 12 flowing down from the liquid distributor 4, for example, absorption The scattering of the solution 11 or the refrigerant liquid 12 can be prevented, respectively, can be prevented from entering the evaporator side or the absorber side, and by installing a baffle plate, the solution can be returned to the absorber side, Further, the refrigerant liquid can be returned to the evaporator side, and the amount of the absorbing solution and the amount of the refrigerant liquid can be ensured. A refrigerant tray 7 is provided under the heat exchange element 2 to collect the refrigerant liquid 12 that does not evaporate. The recovered refrigerant liquid 12 can be circulated and supplied.
Although not shown in FIG. 1, the first fluid is supplied by a communication pipe that communicates the heat exchange element 2 ′, and the third fluid is supplied by a communication pipe that communicates the heat exchange element 2. And it can be set as the plate type absorption and evaporator of an absorption refrigerator using the 1st fluid as cooling water and the 3rd fluid as cold water.
[0013]
FIG. 2 shows a case where the liquid distributor 4 is formed integrally with the baffle plate 3 and can be configured in this way.
FIG. 3 shows a case where the present invention is applied to a regenerator / condenser combination of an absorption refrigerator, in which cooling water is supplied into the heat exchange element 2 and heat source fluid is supplied into the heat exchange element 2 ′ through a communication pipe. The absorbing solution 11 is passed through the liquid distributor 4 to the heat transfer surface on the plate surface of the heat exchange element 2 ′ to evaporate the refrigerant liquid, and the refrigerant 12 is condensed on the heat transfer surface of the plate surface of the heat exchange element 2. The condensed refrigerant liquid 12 is collected by the refrigerant tray 7. Therefore, it is not necessary to install a liquid distributor in the heat exchange element 2, but even if it is attached, it is not necessary to introduce liquid.
In FIG. 4, the schematic block diagram of the plate-type heat exchanger which installed the other liquid distributor of this invention is shown, (a) is a front view, (b) is a partial top view. As described above, one side surface of the bowl-like shape of the liquid distributor 4 can also be used on the plate surface. In this case, the orifice hole can be a notch 8 provided in a contact portion with the plate surface.
[0014]
【The invention's effect】
As described above, according to the present invention, the flow path refracted by the unevenness is formed inside and outside the heat exchange element composed of one or two kinds of portions, and from two fluids having different temperatures. A complex plate heat exchanger for heat exchange can be provided with a low cost and efficient heat exchange function with a small number of parts and a simple manufacturing process.
Also, according to the present invention, since the droplets can be prevented from scattering, the two flowing fluids are not mixed, and when used as an absorption / evaporator and a regeneration / condenser of an absorption refrigerator, Thus, an absorption refrigerator having a high heat exchange function can be obtained.
Furthermore, according to the present invention, since the fluid flowing down on the plate surface can be flown evenly on average, a plate heat exchanger with good heat exchange efficiency was obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram showing an example of a plate heat exchanger of the present invention.
FIG. 2 is a cross-sectional configuration diagram showing another example of the plate heat exchanger of the present invention.
FIG. 3 is a cross-sectional configuration diagram showing another example of the plate heat exchanger of the present invention.
FIG. 4 is a schematic configuration diagram showing another example of the plate heat exchanger of the present invention, (a) a front view and (b) a partial plan view.
FIG. 5 is a partial configuration diagram in which a conventional plate heat exchanger is applied to an absorber / evaporator.
[Explanation of symbols]
1: plate 2, 2 ′: heat exchange element, 3: baffle plate, 4: liquid distributor, 5: orifice hole, 6: peripheral edge, 7: refrigerant tray, 8: notch, 11: second fluid ( Absorbing solution), 12: Fourth fluid (refrigerant liquid)

Claims (4)

In a plate-type heat exchanger for exchanging two sets of fluids having different temperatures at the same time, two plates facing each other are set as one set, and the sealed space inside the two sets is used as a first fluid passage, A heat exchange element (A) having a plate surface as a heat transfer surface and a fluid flowing along the outer surface of the plate as a second fluid and a pair of two plates facing each other, and a sealed space inside the two sheets And a heat exchange element (B) having a plate surface as a heat transfer surface and a fluid flowing along the outer surface of the plate as a fourth fluid, the heat exchange element (A) ( B) are arranged alternately with a predetermined gap with each plate surface facing each other, and a liquid distributor is provided in the gap, and heat exchange is performed from a hole provided in the liquid distributor. On the surface of elements (A) and (B) Plate heat exchanger, characterized respectively the score flow a second fluid and the fourth fluid to. 2. The plate heat exchanger according to claim 1, wherein the liquid distributor is a trough having an orifice hole on a side surface. The plate-type heat exchanger according to claim 1 or 2, wherein the liquid distributor has a bowl shape and uses a plate surface as a side surface of the bowl. On the plate surfaces of the heat exchange elements (A) and (B), there are communication pipes that separately communicate the inner spaces of the heat exchange elements (A) and the inner spaces of the heat exchange elements (B). It forms, The plate type heat exchanger of Claim 1, 2, or 3 characterized by the above-mentioned.

Images