JP2008170090A - Brazing plate for heat transfer and heat exchanger using the same - Google Patents

Abstract

[PROBLEMS] To provide a compact heat transfer brazing plate with a narrow flow path and a heat transfer area when using a non-azeotropic refrigerant mixture to obtain ultra-low temperatures and heat using the same Provide an exchange.
A heat transfer brazing plate in which a bent portion having an obtuse angle at the periphery of a plate, a through hole for inflow / outflow of a refrigerant at an end portion, and a groove portion having a mountain shape in cross section are integrally formed by press working, and the groove portions are alternately arranged. The plate is formed in parallel with the comb teeth in the orthogonal direction from one edge of the plate to the other edge, and the tip of the groove does not reach the other edge. When rotating and laminating, the groove portions do not overlap on the same core, and the groove portion forms a single linear refrigerant flow path with a narrow cross section, and the brazing plate heat exchanger is A plurality of brazing plates for heat transfer are laminated and permanently joined using a brazing material such as copper.
[Selection] Figure 5

Description

  TECHNICAL FIELD The present invention relates to a heat transfer brazing plate and a heat exchanger using the same, and mainly uses a non-azeotropic refrigerant effective in a refrigeration apparatus and a refrigeration apparatus that can also obtain an ultra-low temperature. The present invention relates to a brazing plate type heat exchanger to be used.

  Conventionally, the characteristics required of refrigerants are low boiling point, that is, low cooling temperature, critical temperature is ordinary temperature, that is, condensation is possible at ordinary temperature, latent heat of evaporation is large, that is, per unit weight of refrigerant. The cooling heat quantity is large, the vapor density is large, that is, the volume of the apparatus is small, the compression ratio is small, that is, the compression power is small, and finally, decomposability, corrosiveness, and toxicity. There is no such thing.

  Fluorocarbons, propane, and liquefied carbon dioxide are known as refrigerants that meet this condition. Propane has flammability as its characteristics, and liquefied carbon dioxide must be used at high pressure. Therefore, it has become common to use chlorofluorocarbons except in special cases.

  However, this chlorofluorocarbon system is considered to lead to the destruction of the Earth's ozone layer. As a result, even if the environment is closed like a refrigeration system, it is accompanied by leakage, disposal, etc. It is no longer possible to use CFCs.

  Thus, a refrigerant mixture that uses liquefied carbon dioxide gas as an inert material that suppresses the flammability of propane has been devised as an alternative refrigerant to chlorofluorocarbons. However, although this mixed refrigerant is certainly effective, there are limits to the cooling and freezing temperatures that can be obtained due to the pressure load regulations in the current compression refrigerators, and the ultra-low temperatures beyond that. It has become impossible to obtain.

  Also, in order to obtain ultra-low temperatures using mixed refrigerants, condensers are used in tandem, and the temperature is lowered step by step by passing the condenser through the refrigerant forward and return paths. However, in this case, the system (apparatus) becomes large-scale, and it has been quite difficult to actually construct and install it.

  Focusing on this point, the inventor has developed a refrigeration method and a refrigeration apparatus that can obtain an ultra (very low) temperature using a simple refrigeration cycle. The use of efficient heat exchangers is essential.

  However, the current heat exchanger, that is, the structure of the brazing plate heat exchanger, is a laminate in which plates pressed in the same form are rotated 180 degrees and stacked. Alternatively, the outlet is polymerized as a concentric core, one side is in close contact, and the other side is formed with a gap having the same height as a groove having a mountain-shaped cross section formed on the plate, and this gap is used as a flow path.

  In addition, the groove portions having a mountain-shaped cross section in the conventional heat exchanger are formed in a herringbone shape, and are stacked so as to alternately cross each other. Therefore, a large number of flow channel grooves are formed, and the cross section of the flow channel is obtained by multiplying the height of the groove portions of the two plates by the width of the plate in the flow channel direction. Therefore, this flow path cross section is formed large.

  Since this conventional heat exchanger has such a configuration, each fluid flows while interfering with a groove having a mountain-shaped cross section, and the heat transfer area can be used effectively. However, if a non-azeotropic refrigerant mixture is used, first, the high-boiling point refrigerant liquefies, and the liquefied high-boiling point refrigerant stays at the bottom of the heat exchanger before the heat exchange of the low-boiling point refrigerant is completed. Therefore, the flow is deflected and tends to flow only in a part of the flow path of the heat exchanger, and the entire heat transfer area cannot be effectively used.

This retention of the high-boiling-point refrigerant can be sent out by increasing the flow rate of the fluid, and must pass through the entire surface of the stacked plates, so that the heat transfer area can be used effectively. Here, the conventional heat exchanger is basically designed for heat exchange of liquid (water vs. hot water), and inevitably has a flow rate of 2 to 5 m / S to prevent problems such as passage resistance. If this flow rate is set to about 10 times, the above-mentioned staying refrigerant can be sent out. To obtain this flow rate, in the conventional heat exchanger, the flow passage cross section must be narrowed by reducing the number of stacked stages. In this way, the heat transfer area is reduced, resulting in insufficient heat exchange, and the number of layers must be increased in order to secure and expand the heat transfer area, but the cross section of the flow path is naturally increased, the flow rate is reduced, Reduces heat exchange efficiency.
JP 2006-64331 A

  The problem to be solved by the present invention is that when a non-azeotropic refrigerant mixture is currently used to obtain a low temperature, particularly an ultra-low temperature, the flow rate is increased, that is, the flow path is narrowed, and The heat transfer brazing plate that can sufficiently secure a heat transfer area for heat exchange and can be made compact and a heat exchanger using the same have not existed.

  In order to solve this problem, the brazing plate for heat transfer according to the present invention forms a bent portion with an obtuse angle at the periphery, forms through holes for inflow and outflow of refrigerant at the end, and has a cross-section. In the brazing plate for heat transfer, in which the chevron-shaped groove part is press-molded integrally, the above-mentioned groove parts are alternately formed in parallel to the comb teeth in the orthogonal direction from one edge of the plate to the other edge, and the groove part The tip of the sheet is characterized in that it does not reach the other edge, and when the plurality of brazing plates described above are laminated by rotating one of them 180 degrees, the above-mentioned grooves do not overlap on the same core, A linear refrigerant flow path having a narrow cross section is formed by the groove, and the inflow and outflow through holes described above are located at the same core position during the above-described lamination, Holes in close contact by lamination, the other is characterized by forming a gap of the groove height above.

  Further, the brazing plate type heat exchanger according to the present invention is characterized in that a plurality of the above-described brazing plates for heat transfer are laminated and permanently joined using a brazing material such as copper. The parts have a height of 8 to 9 mm, are characterized by being in close contact with the laminated surfaces in the laminated state and blocking leakage, and using a non-azeotropic refrigerant as the refrigerant.

  The brazing plate for heat transfer according to the present invention and the heat exchanger using the same are configured as described above. For this reason, the flow path formed by the groove portions having a mountain-shaped cross section that does not overlap with each other has a narrow cross section and a linear shape, can increase the flow rate of the refrigerant that passes through it, and send out high-boiling refrigerant that remains. As a result, the refrigerant passes through the entire surface of the stacked plates, the heat transfer area can be used effectively, and a very efficient heat exchanger is obtained.

  This is realized by configuring as illustrated in the drawings and described as the embodiment.

  Next, an example of a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a pressed heat-transfer brazing plate embodying the present invention, FIG. 2 is a cross-sectional view taken along the line AA, and FIG. 3 is the same-shaped plate rotated 180 degrees. FIG. 4 is a cross-sectional view taken along the line BB, FIG. 5 is a conceptual plan view showing a state in which two plates are superposed and laminated, and FIG. FIG. 7 is a front view of a heat exchanger according to the present invention, FIG. 8 is a plan view, and FIG. 9 is a side view.

  In these drawings, reference numeral 1 denotes a first plate obtained by pressing a metal, specifically stainless steel, aluminum or the like. The first plate 1 has a rectangular shape with rounded corners as a whole, and an obtuse bent portion 2 of about 8 to 9 mm is integrally formed on the entire periphery thereof.

  In addition, through holes 3, 3 a, 4, 4 a for inflow or outflow of refrigerant are opened near the four corners of the first plate 1, and 3, 4 or 3 a, 4 a adjacent in the short direction are the plates 1. The same diameter is formed at the equidistant position from the periphery with the height difference 5 formed between the two.

  Further, in the figure, 6, 6... Are concave groove portions having a mountain-shaped cross section, and the groove portions 6, 6... Are through holes formed at portions where the end portions are partly lowered by the height difference 5. 3, 3 a, and the others are formed in a comb-like parallel shape, and are formed in an orthogonal direction from one end along the longitudinal direction of the first plate 1, and the tip thereof does not reach the other end of the plate 1. ing. A portion adjacent to each of the grooves 6, 6... Is a projecting surface 7 having a concave back surface.

  The second plate 1a shown in FIG. 3 is press-processed in the same shape as the first plate 1, and the first plate 1 is rotated 180 degrees, that is, in a state where the top, bottom, left and right are switched. It becomes the lower layer side when it is brazed and polymerized and laminated. That is, as indicated by the reference numerals, the positions of the through holes 3, 3a, 4, 4a are interchanged with point symmetry.

  The first plate 1 is laminated on the upper surface of the second plate 1a. During the superposition and lamination, a brazing material such as copper is interposed between the first plate 1 and the second plate 1a, and both are permanently joined.

  The first plate 1 shown in FIGS. 1 and 2 is laminated on the second plate 1a rotated 180 degrees. At this time, the bent portion 2 of the first plate 1 is outside the second plate 1a. It will be in the state where it will be densely crowned by the peripheral upper part, and the open end of the groove parts 6 of the 2nd plate 1a will be closed tightly, and the leakage of refrigerant will be intercepted.

  In this superposed laminated state, the through holes 3 of the first plate 1 communicate with the through holes 4a of the second plate 1a as concentric positions. Other through holes are also communicated as concentric positions as shown in FIG. In addition, in the communication of each through hole, the part that forms the through hole 3 of the first plate 1 and the part that forms the through hole 4a of the second plate 1a due to the presence of the height difference 5 and the through of the first plate 1. The part that forms the hole 4a, the part that forms the through hole 3a of the second plate 1a, and the part that forms the through hole 4 of the second plate 1a are in close contact with each other. A gap 8 having the same height as the grooves 6, 6... Is formed.

  Moreover, in this superposition | stacking lamination state, each groove part 6,6 ... of the 1st plate 1 and the 2nd plate 1a is set as a staggered state, without superposing | stacking on the same core. Accordingly, the bottom surfaces of the grooves 6, 6,... Of the upper first plate 1 are brought into contact with the upper surface of the projecting surface 7 of the second plate 1a serving as the lower side, and are formed on the rear surface of the projecting surface 7 of the first plate 1. The recessed portion thus formed and the groove portions 6, 6,... Of the second plate 1a are connected as a space to form one refrigerant flow path 9.

  5 and 6 show a state in which two plates 1 and 1a are superposed and laminated, and a single flow path 9 is formed. By laminating and polymerizing several plates alternately rotated 180 degrees, a flow path for another fluid that circulates through one plate is formed.

  The heat exchanger body 10 formed by laminating and superposing a plurality of plates is provided with connecting short tubes 11, 11... Attached to each through-hole portion exposed on the surface side, for example, two kinds of fluids (at least One is a refrigerant inlet and outlet, and a closing plate 12 that closes each through hole is fixed on the bottom side.

  The brazing plate type heat exchanger according to the present embodiment is configured as described above. Therefore, the flow path 9 through which the refrigerant passes is made narrow and linear in the shape of the grooves 6, 6,... Of each plate 1, 1a, and the flow velocity through which the refrigerant passes is increased. This flow rate can be about 10 times as high as 20 to 50 m / S, compared with the conventional groove portion having a herringbone type.

  By accelerating this refrigerant flow rate, even when non-azeotropic refrigerant is used, the power to send out stagnation of the high-boiling point refrigerant that has been liquefied first is obtained, and the entire surface of the stacked plates is used as a heat transfer surface. Therefore, a very effective heat exchange effect can be obtained.

  In this way, the brazing plate type heat exchanger in this embodiment can secure a heat transfer area without increasing the number of stacked plates more than necessary, so that the product as a compact form compared to the conventional one Therefore, even a system incorporating this can be made compact as a whole.

  The brazing plate type heat exchanger according to the present invention is configured as described above, and even if stainless steel is used as a material, it is not limited to 316 having strong corrosion resistance corresponding to various liquids as in the past, but may be 304. It is also possible to use aluminum. This is because the main object of the present invention is in gas-to-gas heat exchange to obtain ultra-low temperatures rather than liquids. However, the configuration of the present application can be applied not only to this gas-to-gas heat exchange but also to heat exchange in liquid-to-liquid such as water or gas-to-liquid.

It is a top view which shows one pressed plate used for this invention. It is sectional drawing along the AA line. It is a top view which shows the 2nd plate of the state which rotated the plate of the same shape 180 degree | times. It is sectional drawing along the BB line. It is a conceptual top view of the state by which two plates were superposed and laminated. It is sectional drawing along CC line. It is the whole front view. It is a top view. It is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st plate 1a 2nd plate 2 Bending part 3 Through-hole 3a Through-hole 4 Through-hole 4a Through-hole 5 Height difference 6 Groove part 7 Protruding surface 8 Space | gap 9 Flow path 10 Heat exchanger body 11 Connection short tube 12 Blocking plate

Claims (6)

  In the brazing plate for heat transfer in which a bent portion having an obtuse angle is formed at the periphery, a through hole for inflow and outflow of refrigerant is formed at an end portion, and a groove portion having a mountain-shaped cross section is integrally formed by press working, The groove portions are alternately formed in parallel with the comb teeth in the orthogonal direction from one edge of the plate to the other edge, and the tip of the groove does not reach the other edge. Brazing plate   When a plurality of the above described brazing plates are laminated by rotating one of them 180 degrees, the above-mentioned groove portions do not overlap on the same core, and a single linear refrigerant channel whose cross section is narrowed by the groove portions. The brazing plate for heat transfer according to claim 1, wherein:   The inflow and outflow through holes described above are located at the same core position during the above-described lamination, one of the through holes is closely attached by the lamination, and the other forms a gap having the above-described groove height. The brazing plate for heat transfer according to claim 1 or 2.   A heat exchanger characterized in that a plurality of the above-described brazing plates for heat transfer are laminated and permanently joined using a brazing material such as copper.   5. The heat exchanger according to claim 4, wherein the bent portion has a height of 8 to 9 mm, and is in close contact with the laminated surface in a laminated state to block leakage.   The heat exchanger according to claim 4 or 5, wherein a non-azeotropic refrigerant is used as the refrigerant.

Images