JP2000266478A - Plate heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate heat exchanger having high heat exchange efficiency by liquid flowing down evenly on plates without dispersion of liquid droplets in liquid supply. SOLUTION: The plate heat exchanger for exchanging heat between two sets of liquids at the same time comprises a heat exchange element (A) 2 wherein two plates facing each other is integrated, a space inside the two plates is to be a route of a first fluid and a fluid flowing along the outside surfaces of the plates is to be a second fluid and a heat exchange element (B) 2' wherein two plates 1 facing each other is integrated, a space inside the two plates is to be a route of a third fluid and a fluid flowing along the outside surfaces of the plates is to be a fourth fluid. The heat exchange elements (A), (B) are provided in line plurally alternately, and liquid distributors 4 for flowing the liquids respectively are provided on upper parts of surfaces of the heat exchange elements (A) and (B). The liquid distributors comprise troughs provided with orifice holes 5 on side surfaces, or plate surfaces can be utilized as the side surfaces of the troughs.

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 in which plates are stacked and two fluids are alternately flowed between the plates to exchange heat. The present invention relates to a plate heat exchanger suitable for a case where at least one of the fluids is low-pressure steam (or a phase-change vaporization or liquefaction from a vapor) such as a regenerator or a condenser.

[0002]

2. Description of the Related Art Generally, unless the vapor velocity at the outlet of an evaporator or the vapor velocity at the entrance of an absorber is controlled within about 50 m / s, the flow resistance increases and the refrigeration function deteriorates. Conventionally,
As a plate-type heat exchanger, as shown in FIG. 5, an absorber element 2 and an evaporator element 2 'are alternately arranged with their plate surfaces facing each other. In this case, the size of the steam passage with respect to the surface of the plate 1 is equal to the plate height × the plate width, and the gap between the plates is not limited by the steam flow rate, 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 by combining two plates, and sequentially attach them one by one to the cold water header and the cooling water header. However, the shapes of the absorber and the evaporator are different, and the types of parts are increased.

Further, for example, when an absorber element and an evaporator element are alternately arranged, since 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, the droplets scatter. When the absorbing solution enters the refrigerant, the refrigerant is contaminated, raises the boiling point, raises the evaporation temperature, degrades the performance as a refrigerator, and also reduces the amount of the solution on the heat transfer surface, and becomes wet. There is a problem that becomes difficult. On the other hand, when the refrigerant liquid scatters as droplets and enters the absorber side, the solution concentration decreases,
The absorption capacity is reduced, and the performance as a refrigerator is deteriorated. In addition, since the refrigerant liquid does not evaporate and jumps out as it is, 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, and there is also a problem that it is difficult to get wet. is there.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and when liquid is supplied between heat exchange elements, the liquid does not scatter and the liquid flows down on the plate on average, resulting in high heat. It is an object to provide a plate heat exchanger having an exchange efficiency.

[0005]

According to the present invention, there is provided a plate heat exchanger for simultaneously exchanging two sets of fluids having different temperatures.
A set of two plates facing each other is used, a sealed space inside the two plates is used as a first fluid passage, a plate surface is used as a heat transfer surface, and a fluid flowing along the outer surface of the plate is used as a second fluid. A heat exchange element (A) and a pair of plates facing each other form a set, a sealed space inside the two plates serves as a third fluid passage, and a plate surface serves as a heat transfer surface. A heat exchange element (B) having a flowing fluid as a fourth fluid, wherein the heat exchange elements (A) and (B) are separated by a predetermined gap so that the respective plate faces face each other, A plurality of liquid distributors are arranged alternately, and a liquid distributor through which the second fluid and the fourth fluid flow respectively is provided above the surfaces of the heat exchange elements (A) and (B) in the gap.

In the plate type heat exchanger, a gutter having an orifice hole on a side surface can be used as a liquid distributor, and a plate surface can be used as a gutter-like side surface of the gutter. The heat exchange elements (A) and (B)
It is preferable that a communication pipe is provided on the plate surface for communicating the inner space of the heat exchange element (A) and the inner space of the heat exchange element (B) separately.

[0007]

Next, the present invention will be described in detail.
In the plate used in the present invention, two plates having uneven portions are overlapped so as to form a space inside, and when the communication pipes (fluid inlets and outlets) of the peripheral portion and the openings at both ends are simply overlapped, the entire periphery is covered. When light contact (line contact) is applied and a force is applied in the overlapping direction, the shape of the contact portion changes to form surface contact. A shape suitable for sealing the periphery by tangling (phrasing) can be used. That is, in the case of the above-mentioned plate, in the case of brazing, in order to make the plates adhere to each other, brazing is performed while applying a force. Is preferred.

[0008] When the two plates as described above are overlapped with the brazing material placed (painted) on the portions to be contacted, a fluid flow path is formed between the spaces from the openings formed at both ends of the plates. Having a heat exchanger. In the present invention, in addition to brazing (phrasing), a case in which a gasket is inserted therebetween to apply a force from the outside or a case in which the gasket is sealed by welding is also 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 two-dimensionally bent channel can be formed with a relatively simple configuration. Further, in the opening communicating pipes at both ends of the plate, since the heat exchange element and the scattering prevention means of another flow path are inserted between the heat exchange elements of the same flow path, the element and the prevention means can be inserted. A communication pipe of a length having an interval and an interval at which a flow path can be formed on the outer surface of the plate is provided, and the communication pipe can be provided on one side of both ends of the plate.For the manufacture of a heat exchanger, a spacer is provided between the elements. It can be inserted and brazed all at once while applying force in the furnace.

Providing a swivel at one end of the communicating pipes at both ends of the plate makes it easy to position the fitting 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. The liquid distributor provided on the upper surface of the heat exchange element of the present invention is provided in a gutter shape in parallel with the plate surface, and an orifice hole for flowing liquid toward the plate surface is provided on a side surface. The liquid distributor may use a plate surface as one side surface of the gutter. This allows
The liquid can be prevented from being scattered when the fluid is supplied to the plate surface, and the fluid can be evenly distributed over the plate surface. Further, a scattering 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, whereby the scattering of the fluid supplied on the plate surface can be achieved. Can be further prevented. The scatter prevention means may be a baffle plate composed of two plates so as to return each scattered liquid to the heat transfer surface of the scatter source.

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. 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. FIG. 1 is a sectional view showing an example of a plate heat exchanger according to the present invention, which is configured by alternately connecting three heat exchange elements 2, 2 ′. The heat exchange element 2 is formed by laminating the two plates 1 and fixing them by welding or brazing between the contact portion of the uneven pattern and the peripheral portion 6. A baffle plate 3 is provided between the heat exchange elements 2 and 2 'to prevent the fluid flowing on the plate surface from scattering. A liquid distributor 4 is provided above the heat exchange elements 2, 2'.
The fluid flows from the orifice hole 5 of the liquid distributor along the heat transfer surface of the plate surface.

As described above, 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,
Second fluid 11 or fourth fluid 1 flowing down from liquid distributor 4
2. For example, it is possible to prevent the absorption solution 11 or the refrigerant liquid 12 from scattering, to prevent the absorption solution 11 or the refrigerant liquid 12 from entering the evaporator side or the absorber side, respectively, and to install a baffle plate.
The solution can be returned to the absorber side, the refrigerant liquid can be returned to the evaporator side, and the absorption solution amount and the refrigerant liquid amount can be secured. A refrigerant tray 7 is provided below the heat exchange element 2, and collects a refrigerant liquid 12 that does not evaporate. The collected refrigerant liquid 12 can be circulated and supplied. In FIG. 1, although not shown, the first fluid is supplied by a communication pipe communicating with the heat exchange element 2 ′, and the third fluid is supplied by a communication pipe communicating with the heat exchange element 2. Then, the plate-type absorption / evaporator of the absorption refrigerator can be obtained by using the first fluid as the cooling water and the third fluid as the cold water.

FIG. 2 shows a case where the liquid distributor 4 is formed integrally with the baffle plate 3, and such a configuration can be adopted. FIG. 3 shows a case where the present invention is applied to a combination of a regenerator / condenser of an absorption refrigerator, and cooling water,
A heat source fluid is supplied into the heat exchange element 2 ′ through the communication pipe, and the absorbing solution 11 is supplied through the liquid distributor 4 to the heat exchange element 2 ′.
The refrigerant liquid is allowed to flow on the heat transfer surface on the plate surface to evaporate the refrigerant liquid, and the refrigerant 12 is condensed on the heat transfer surface on the plate surface of the heat exchange element 2. The condensed refrigerant liquid 12 is collected in the refrigerant tray 7.
Therefore, it is not necessary to install a liquid distributor in the heat exchange element 2, but it is sufficient if no liquid is introduced even if it is attached. In FIG.
FIG. 3 is a schematic configuration diagram of a plate heat exchanger provided with another liquid distributor of the present invention, where (a) is a front view and (b) is a partial plan view. As described above, one side of the gutter-like side of the liquid distributor 4 can also be used as the plate surface, and in this case, the orifice hole can be a notch 8 provided in a contact portion with the plate surface.

[0014]

As described above, according to the present invention,
A complicated plate-type heat exchanger, in which a flow path bent by unevenness is formed inside and outside of a heat exchange element composed of one or two types of parts and exchanges heat from two fluids having different temperatures, With a small number of parts and a simple manufacturing process,
A heat exchanger having a low-cost and efficient heat exchange function can be provided. Further, according to the present invention, since the scattering of the liquid droplets can be prevented, the two flowing fluids do not mix, and when used as an absorption / evaporator and a regeneration / condenser of an absorption refrigerator, it can be used as a refrigerator. Thus, an absorption refrigerator having a high heat exchange function can be obtained without deteriorating the performance of the device and without causing a problem that it becomes difficult to get wet. Further, according to the present invention, since the fluid flowing down on the plate surface can be evenly distributed on the plate surface, a plate heat exchanger having good heat exchange efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a plate heat exchanger according to the present invention.

FIG. 2 is a sectional configuration view showing another example of the plate heat exchanger of the present invention.

FIG. 3 is a sectional view 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, in which (a) is a front view and (b) is 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 ': heat exchange element, 3: baffle plate
4: liquid distributor, 5: orifice hole, 6: peripheral part, 7: refrigerant tray, 8: notch, 11: second fluid (absorbing solution),
12: Fourth fluid (refrigerant liquid)

Claims (4)

[Claims] 1. A plate heat exchanger for simultaneously exchanging heat of two sets of fluids having different temperatures, wherein two plates facing each other form a set, and a sealed space inside the two plates is defined as a first space. A heat exchange element (A) in which a fluid flows along the 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 are formed as a set. A closed space of the third fluid passage, the plate surface as a heat transfer surface,
A heat exchange element (B) having a fluid flowing along the outer surface of the plate as a fourth fluid, wherein the heat exchange elements (A) and (B)
And, in such a manner that the respective plate surfaces face each other, with a predetermined gap therebetween, and a plurality of them are alternately arranged, and in the gap,
Each of the heat exchange elements (A) and (B) has a second
A plate type heat exchanger comprising a liquid distributor for flowing a fluid and a fourth fluid. 2. The plate heat exchanger according to claim 1, wherein the liquid distributor is a gutter having an orifice hole on a side surface. 3. The plate heat exchanger according to claim 1, wherein the liquid distributor has a gutter shape, and a plate surface is used as a side surface of the gutter. 4. The space inside the heat exchange element (A) and the space inside the heat exchange element (B) are separately provided on the plate surfaces of the heat exchange elements (A) and (B). 4. A communication pipe for communication is formed.
4. The plate heat exchanger according to 1.