JP6682017B2 - Twist tube heat exchanger - Google Patents

Description

  The present invention relates to a twisted tube heat exchanger including a first pipe and a second pipe spirally provided on an outer peripheral portion of the first pipe.

  Conventionally, heat exchange is provided, which includes a first pipe and a second pipe provided on an outer peripheral portion of the first pipe, and heats a first fluid such as water flowing in the first pipe with a refrigerant flowing in the second pipe. Vessels are known (see, for example, Patent Document 1). In the heat exchanger described in Patent Document 1, the second pipe is arranged along the length direction of the first pipe. In other words, in the heat exchanger described in Patent Document 1, the first pipe and the second pipe are arranged in parallel. And the heat exchanger of patent document 1 covers the outer peripheral part of a 1st piping and a 2nd piping with a resin layer, and the 2nd piping is brought into close contact with the 1st piping. The resin layer that covers the outer peripheral portions of the first pipe and the second pipe also functions as a heat insulating material. Further, this resin layer is provided on the outer peripheral portions of the first pipe and the second pipe by the extrusion method.

  Further, a twisted tube heat exchanger has been conventionally proposed as a heat exchanger that heats a first fluid such as water flowing in the first pipe with a refrigerant flowing in the second pipe. The twisted tube heat exchanger includes a first pipe having a spiral groove formed on the outer periphery thereof and a second pipe wound around the groove of the first pipe. That is, the second pipe is spirally provided on the outer peripheral portion of the first pipe.

JP, 2004-347178, A

  In the heat exchanger described in Patent Document 1, a resin layer that functions as a heat insulating material is formed by an extrusion method. That is, the heat exchanger described in Patent Document 1 has a configuration in which a heat insulating material is provided over the entire heat exchanger. Therefore, the structure in which the heat insulating material is provided as in Patent Document 1 has a problem that the material cost of the heat exchanger increases.

  Further, the twisted tube heat exchanger has a complicated shape in which the second pipe is spirally provided on the outer peripheral portion of the first pipe. Therefore, it is practically impossible to form the resin layer on the outer peripheral portion of the twisted tube heat exchanger by the extrusion method. Therefore, the conventional twisted tube heat exchanger has a problem in that the heat insulating layer cannot be provided on the outer peripheral portion and the second pipe is corroded.

  More specifically, since both ends of the second pipe are connected to a pipe that supplies a refrigerant to the second pipe and a pipe that causes a refrigerant to flow out from the second pipe, it is not wound around the outer periphery of the first pipe. Has become. Therefore, the middle portion of the second pipe is wrapped around the outer peripheral portion of the middle portion of the first pipe. And the 2nd piping part wound by the outer peripheral part of the 1st piping and the 1st piping are joined by solder etc., for example. Hereinafter, the range in which the first pipe and the second pipe are joined is referred to as a first range, and the region is located closer to the end side of the first pipe than the first range, and the first pipe and the second pipe are joined together. The range that has not been set is referred to as a second range.

  Since the twisted tube heat exchanger is configured as described above, the first fluid flowing into the first pipe first flows in the second range. Then, the first fluid in the first pipe flows into the first range and is heated by the refrigerant flowing in the second pipe. That is, the first fluid flowing through the first pipe portion existing in the second range has a low temperature because it is not yet heated by the refrigerant. Therefore, the first pipe portion existing in the second range has a temperature lower than the ambient temperature and is liable to be condensed. Further, the second range is a range in which the first pipe and the second pipe are not joined, and a gap is formed between the first pipe and the second pipe. Therefore, when dew condensation occurs, the dew condensation water bridges in the second range where the gap between the first pipe and the second pipe is small, that is, in the second range near the boundary with the first range. It is held in the form of. Here, since the first fluid in the first pipe is heated, a refrigerant having a temperature higher than that of the first fluid flows through the second pipe. That is, the second pipe has a higher temperature than the first pipe. Therefore, if dew condensation water is held in a form of a bridge between the first pipe and the second pipe, the portion acts as a temperature difference battery, and the second pipe on the high temperature side is corroded. .

  The present invention has been made to solve the above problems, and provides a twisted tube heat exchanger capable of suppressing the corrosion of the second pipe and suppressing an increase in material cost. With the goal.

  In the twisted tube heat exchanger according to the present invention, a spiral groove portion is formed on an outer peripheral portion, a first pipe in which a first fluid flows, and a part of the first pipe are wound around the groove portion. And a second pipe in which a refrigerant for heating the first fluid flows, and a range in which the first pipe and the second pipe are joined is defined as a first range. When the range existing on the end side of the first pipe with respect to the first range and in which the first pipe and the second pipe are not joined is defined as the second range, the first range and the second range are defined. A part of the range including a boundary with the range is wound so as to cover an outer peripheral part of the first pipe and the second pipe in the boundary part and an outer peripheral part of the first pipe in the second range. It is a heat exchanger equipped with a heat insulating material.

  The twisted tube heat exchanger according to the present invention can be used as a configuration in which the first fluid flows from the second range toward the first range. Here, the twisted tube heat exchanger according to the present invention has an outer peripheral portion of the first pipe and the second pipe in a boundary portion between the first range and the second range, and an outer peripheral portion of the first pipe in the second range. Insulation material is wrapped around to cover. That is, in the twisted tube heat exchanger according to the present invention, the dew condensation water bridged between the first pipe and the second pipe acts as a temperature difference battery, and the second pipe is corroded with a heat insulating material. It's wrapped around. The method of attaching the heat insulating material by winding the heat insulating material is a method of easily attaching the heat insulating material even in a twisted tube heat exchanger having a complicated shape, unlike the method of attaching the heat insulating material using the extrusion method. Therefore, the twisted tube heat exchanger according to the present invention can prevent the condensed water from bridging between the first pipe and the second pipe, and the portion acts as a temperature difference battery to the second pipe. It is possible to suppress the occurrence of corrosion. Moreover, since the heat insulation material is provided only in part in the twisted tube heat exchanger according to the present invention, an increase in the material cost of the twisted tube heat exchanger can be suppressed.

It is a perspective view showing a twisted tube type heat exchanger concerning an embodiment of the invention. It is a principal part enlarged view which shows the insulation material attachment range vicinity in the twisted tube of the twisted tube heat exchanger which concerns on embodiment of this invention, and is a figure which shows the state which has not attached the heat insulating material. It is a principal part enlarged view which shows the insulation material attachment range vicinity in the twisted tube of the twisted tube heat exchanger which concerns on embodiment of this invention, and is a figure which shows the state in which the heat insulating material is attached. It is sectional drawing of the heat insulating material attachment range in the twisted tube of the twisted tube heat exchanger which concerns on embodiment of this invention. It is a figure which shows an example of the heat insulating material wound around the twisted tube of the twisted tube type heat exchanger which concerns on embodiment of this invention. It is a figure which shows another example of the heat insulating material wound around the twisted tube of the twisted tube heat exchanger which concerns on embodiment of this invention.

Embodiment.
FIG. 1 is a perspective view showing a twisted tube heat exchanger according to an embodiment of the present invention.
The twisted tube heat exchanger 100 includes a twisted tube 1. Although details of the twisted tube 1 will be described later, the twisted tube 1 includes, as described later, a first pipe 10 through which a first fluid such as water flows, and a second pipe 20 through which a refrigerant that heats the first fluid flows. (See FIGS. 2 and 3 described later). Further, in the twisted tube heat exchanger 100 according to the present embodiment, the heat insulating material 30 is wound around a part of the twisted tube 1. The twisted tube heat exchanger 100 according to the present embodiment uses the long (long) twisted tube 1. For this reason, the twisted tube heat exchanger 100 according to the present embodiment has a shape in which the twisted tube 1 is wound in a plurality of stages like a coil (coil). The length and the number of steps of the claw-shaped portion may be appropriately determined according to the length of the twisted tube 1.

  The twisted tube heat exchanger 100 is used, for example, as a water-refrigerant heat exchanger for a heat pump water heater. In this case, the water serving as the first fluid is heated by the twisted tube heat exchanger 100. Specifically, water flows into the twisted tube 1 from the inlet-side end 11 of the twisted tube 1. More specifically, water flows into the inside of the first pipe 10 from the inlet-side end portion 11 of the first pipe 10 forming the twisted pipe 1. The water that has flowed into the first pipe 10 is heated by the refrigerant that flows inside the second pipe 20 until it flows out from the outlet-side end 12, and becomes hot water.

  Next, details of the twisted tube 1 according to the present embodiment will be described.

  FIG. 2 is an enlarged view of an essential part showing the vicinity of the heat insulating material mounting range in the twisted tube of the twisted tube heat exchanger according to the embodiment of the present invention, and is a diagram showing a state in which the heat insulating material is not attached. FIG. 3 is an enlarged view of an essential part showing the vicinity of a heat insulating material attachment range in the twisted tube of the twisted tube heat exchanger according to the embodiment of the present invention, and is a diagram showing a state in which the heat insulating material is attached. Moreover, FIG. 4 is a cross-sectional view of a heat insulating material mounting range in the twisted tube of the twisted tube heat exchanger according to the embodiment of the present invention. Note that FIG. 4 is a sectional view perpendicular to the length direction of the first pipe 10. In other words, FIG. 4 is a sectional view perpendicular to the pipe axis direction of the first pipe 10. Further, FIG. 4 is a cross-sectional view at a portion where the first pipe 10 and the second pipe 20 are joined.

  The twisted tube 1 includes a first pipe 10 and a second pipe 20 spirally provided on the outer peripheral portion of the first pipe 10. The first pipe 10 and the second pipe 20 are formed of a material having good thermal conductivity. In the present embodiment, the first pipe 10 and the second pipe 20 are made of, for example, copper or a copper alloy.

  As described above, the first pipe 10 is a pipe through which the first fluid such as water flows. A spiral groove 13 around which the second pipe 20 is wound is formed on the outer periphery of the first pipe 10. Specifically, in the present embodiment, the spiral mountain portion 14 and the spiral valley portion 15 are alternately formed on the outer peripheral portion of the first pipe 10. Then, the valley portion 15 is used as the groove portion 13. In this embodiment, a plurality of grooves 13 are formed. More specifically, in the present embodiment, three groove portions 13 are formed. Therefore, as shown in FIG. 4, the cross-sectional shape of the first pipe 10 in the groove 13 is triangular. This is because the first pipe 10 is formed by twisting the circular pipe into three lines, so that three sides are formed. Therefore, when the four grooves 13 are formed in the first pipe 10, the cross-sectional shape of the first pipe 10 in the groove 13 is a quadrangle.

  As described above, the second pipe 20 is a pipe through which the refrigerant that heats the first fluid flows. The second pipe 20 is wound around the groove 13 of the first pipe 10. In this embodiment, a plurality of (more specifically, three) groove portions 13 are formed as described above. Therefore, as many second pipes 20 as the number of threads are wound around the outer periphery of the first pipe 10.

  Here, since both ends of the second pipe 20 are connected to a pipe for supplying the refrigerant to the second pipe 20 and a pipe for causing the refrigerant to flow out from the second pipe 20, they are wound around the outer periphery of the first pipe 10. Not in a state. Therefore, the middle part of the second pipe 20, that is, a part thereof is wound around the outer peripheral part (that is, the groove part 13) of the middle part of the first pipe 10. Then, the portion of the second pipe 20 wound around the groove 13 of the first pipe 10 and the first pipe 10 are joined by, for example, solder or the like.

  In the present embodiment, the range in which the first pipe 10 and the second pipe 20 are joined is defined as the first range 41. Further, a range existing on the inlet side end 11 side of the first pipe 10 with respect to the first range 41 and in which the first pipe 10 and the second pipe 20 are not joined is defined as a second range 42. Further, the boundary between the first range 41 and the second range 42 is defined as a boundary 43. That is, the boundary portion 43 is the endmost portion in the range where the first pipe 10 and the second pipe 20 are joined.

  As shown in FIG. 3, the twisted tube 1 according to the present embodiment is provided with the above-described heat insulating material 30 in a partial range including the boundary portion 43. Specifically, the heat insulating material 30 is wound so as to cover the outer peripheral portions of the first pipe 10 and the second pipe 20 in the boundary portion 43 and the outer peripheral portion of the first pipe 10 in the second range 42. The length of the heat insulating material 30 (specifically, the length in the axial direction of the twisted tube 1) is not particularly limited, but workability for winding, the cost of the heat insulating material 30, and dew condensation on the twisted tube 1 are assumed. Considering the length of the range and the like, about 20 cm is suitable from the boundary portion 43 in the second range 42 direction. Further, the heat insulating material 30 is preferably formed of a material in which a component that causes corrosion in the first pipe 10 and the second pipe 20 is difficult to elute, and is preferably formed of, for example, polyethylene foam resin.

  The heat insulating material 30 is fixed, for example, by applying an adhesive agent on the entire surface of one side and adhering it to the twisted tube 1 with the adhesive agent. When fixing the heat insulating material 30 in this manner, the adhesive used should not be one that elutes components (hydrochloric acid, sulfuric acid, acetic acid, etc.) that cause corrosion in the first pipe 10 and the second pipe 20. Better, for example acrylic adhesives are desirable.

  FIG. 5: is a figure which shows an example of the heat insulating material wound around the twisted tube of the twisted tube heat exchanger which concerns on embodiment of this invention. FIG. 6 is a diagram showing another example of the heat insulating material wound around the twisted tube of the twisted tube heat exchanger according to the embodiment of the present invention.

  The heat insulating material 30 before being wound around the twisted tube 1 has, for example, a rectangular shape, and has the same number of holes 31 as the second pipe 20. The hole 31 is a hole into which the second pipe 20 is inserted. The diameter of the hole 31 is, for example, substantially the same as the outer diameter of the second pipe 20. The position of the hole 31 is not particularly specified, but the hole 31 is formed, for example, at a substantially central position in the short side direction. In addition, the length L2 of the short side of the heat insulating material 30 is preferably a dimension that can cover almost the entire circumference of the outer peripheral portions of the first pipe 10 and the second pipe 20 at the boundary portion 43 (see FIG. 4). . Further, in the present embodiment, as shown in FIG. 3, the end portion of the heat insulating material 30 in the longitudinal direction is arranged near the boundary portion 43. Therefore, when the heat insulating material 30 covers a range of about 20 cm from the boundary portion 43 in the second range 42 direction, the length L1 of the long side of the heat insulating material 30 is also preferably about 20 cm. When covering the first range 41 side with respect to the boundary part 43 with the heat insulating material 30, the length L1 of the long side of the heat insulating material 30 may be increased by the length covering the first area 41.

  Further, the heat insulating material 30 is formed with a notch extending from the hole 31 to the end of the heat insulating material 30. When the second pipe 20 is inserted into the hole 31, the second pipe 20 is easily inserted into the hole 31 by inserting the second pipe 20 into the hole 31 through the cut 32 from the end of the heat insulating material 30. The formation direction of the cut 32 is not particularly limited. The cut 32 may be formed toward the long side as shown in FIG. 5, or the cut 32 may be formed toward the short side as shown in FIG.

Subsequently, a heating operation of the first fluid in the twisted tube heat exchanger 100 according to the present embodiment will be described.
The first fluid flows into the inside of the first pipe 10 from the inlet-side end 11 of the first pipe 10 forming the twisted pipe 1. The first fluid flows inside the first pipe 10 from the second range 42 toward the first range 41. Then, the first fluid is heated by the refrigerant flowing inside the second pipe 20 while flowing through the first range 41. The heated first fluid flows out of the twisted tube heat exchanger 100 from the outlet-side end 12 of the first pipe 10.

  Here, since the first fluid flowing through the portion of the first pipe 10 existing in the second range 42 has not been heated by the refrigerant yet, it has the lowest temperature among the first fluid existing in the first pipe 10. There is. For this reason, the first pipe portion existing in the second range has a temperature lower than the ambient temperature, and becomes an environment in which dew condensation easily occurs. Therefore, when the twisted tube heat exchanger 100 is not provided with the heat insulating material 30, dew condensation occurs on the first pipe portion existing in the second range.

  The second range 42 is a range in which the first pipe 10 and the second pipe 20 are not joined, and the gap 2 is formed between the first pipe 10 and the second pipe 20 (see FIG. 2). . For this reason, when dew condensation occurs in the first pipe portion existing in the second range, the dew condensation water is retained in a bridged form in the second range 42 near the boundary portion 43 where the gap 2 becomes small. Here, in the second pipe 20, in order to heat the first fluid in the first pipe 10, a refrigerant having a temperature higher than that of the first fluid flows. That is, the second pipe 20 has a higher temperature than the first pipe 10. For this reason, when the condensed water is held in a form of a bridge between the first pipe 10 and the second pipe 20, the portion acts as a temperature difference battery, and the second pipe 20 on the high temperature side is corroded. Resulting in.

  However, in the twisted tube heat exchanger 100 according to the present embodiment, the heat insulating material 30 is wound around a part of the range including the boundary portion 43. That is, in the twisted pipe heat exchanger 100, the dew condensation water bridged between the first pipe 10 and the second pipe 20 acts as a temperature difference battery, and the second pipe 20 is corroded at a location where heat is generated. The material 30 is wrapped around. Therefore, in the twisted tube heat exchanger 100 according to the present embodiment, the surrounding air is cooled by a part of the range including the boundary portion 43, that is, dew condensation occurs in the part of the range including the boundary portion 43. Can be suppressed. Therefore, the twisted tube heat exchanger 100 according to the present embodiment can suppress the corrosion of the second pipe 20.

  As described above, the twisted tube heat exchanger 100 according to the present embodiment has a shape in which the twisted tube 1 is wound in a plurality of stages like a coil (coil). Therefore, when the heat insulating material 30 is not provided, the dew condensation water can bridge between the first pipe 10 portion existing in the second range 42 and the twisted pipe 1 portion arranged above the portion. There is a nature. When the condensed water bridges in this way, the location acts as a temperature difference battery, and the second pipe 20 on the high temperature side is corroded. However, as shown in FIGS. 1 and 3, in the twisted tube heat exchanger 100 according to the present embodiment, the range in which the heat insulating material 30 is wound and the twisted tube arranged above the range. The heat insulating material 30 is placed between the first portion and the first portion. Therefore, in the twisted tube heat exchanger 100 according to the present embodiment, it is possible to suppress the corrosion of the second pipe 20 in the first range 41.

  As described above, in the twisted tube heat exchanger 100 according to the present embodiment, the spiral groove portion 13 is formed in the outer peripheral portion, and the first pipe 10 in which the first fluid flows and the groove portion 13 of the first pipe 10 are formed. A twisted tube 1 is provided, which is partially wound and has a second pipe 20 in which a refrigerant for heating the first fluid flows. The twisted tube heat exchanger 100 according to the present embodiment includes, in a part of the range including the boundary 43 between the first range 41 and the second range 42, the first pipe 10 and the first pipe 10 at the boundary 43. The heat insulating material 30 is provided so as to cover the outer peripheral portion of the second pipe 20 and the outer peripheral portion of the first pipe 10 in the second range 42.

  In the twisted tube heat exchanger 100 according to the present embodiment, the dew condensation water bridged between the first pipe 10 and the second pipe 20 acts as a temperature difference battery, and the second pipe 20 is corroded. A heat insulating material 30 is wrapped around the. The method of attaching the heat insulating material 30 by winding the heat insulating material 30 is a method of easily attaching the heat insulating material 30 even in the twisted tube heat exchanger 100 having a complicated shape, unlike the method of attaching the heat insulating material using the extrusion method. Therefore, the twisted tube heat exchanger 100 according to the present embodiment can suppress the condensation water from bridging between the first pipe 10 and the second pipe 20, and the portion acts as a temperature difference battery. As a result, it is possible to suppress the occurrence of corrosion in the second pipe 20. Further, since the twisted tube heat exchanger 100 according to the present embodiment is provided with the heat insulating material 30 only partially, it is possible to suppress an increase in the material cost of the twisted tube heat exchanger 100.

  The heat insulating material 30 is formed of, for example, polyethylene foam resin. This is because the polyethylene foam resin is a material in which a component that causes corrosion in the first pipe 10 and the second pipe 20 is difficult to elute.

  Further, the heat insulating material 30 is formed with, for example, a hole 31 into which the second pipe 20 is inserted and a cut 32 extending from the hole 31 to the end of the heat insulating material 30. When the second pipe 20 is inserted into the hole 31, the second pipe 20 is easily inserted into the hole 31 by inserting the second pipe 20 into the hole 31 through the cut 32 from the end of the heat insulating material 30. That is, the attachment of the heat insulating material 30 becomes easier.

  Further, when the twisted tube 1 is wound in a multi-stepped shape, the partial range (the range around which the heat insulating material 30 is wound) and the twisted tube arranged above the partial range. The heat insulating material 30 is disposed between the first portion and the first portion. Corrosion of the second pipe 20 in the part of the twisted pipe 1 arranged above the partial range (the range around which the heat insulating material 30 is wound) can also be suppressed.

  1 twisted pipe, 2 gap, 10 first pipe, 11 inlet end, 12 outlet end, 13 groove, 14 crest, 15 valley, 20 second pipe, 30 heat insulating material, 31 hole, 32 cut, 41 1st range, 42 2nd range, 43 boundary part, 100 twist tube type heat exchanger.

Claims (5)

A first pipe in which a spiral groove is formed in the outer periphery and a first fluid flows inside;
A second pipe, a part of which is wound around the groove of the first pipe, in which a refrigerant for heating the first fluid flows,
Equipped with a twisted tube having
A range in which the first pipe and the second pipe are joined is defined as a first range, and the first pipe and the second pipe are present on the end side of the first pipe with respect to the first range. If the range where the pipe is not joined is defined as the second range,
In a part of the range including the boundary between the first range and the second range, the outer circumference of the first pipe and the second pipe at the boundary, and the outer circumference of the first pipe in the second range. A twisted tube heat exchanger having a heat insulating material wound so as to cover the section.   The twisted tube heat exchanger according to claim 1, wherein the heat insulating material is formed of polyethylene foam resin.   The twisted tube heat exchanger according to claim 1 or 2, wherein the heat insulating material has a hole into which the second pipe is inserted and a notch extending from the hole to an end of the heat insulating material. . The twisted tube is wound in a multi-stepped form,
The said heat insulating material is arrange | positioned between the said one part range and the said twist pipe part arrange | positioned above this one part range, The heat insulating material is arrange | positioned in any one of Claims 1-3. Twisted tube heat exchanger. Torsion tube type heat exchanger according to any one of claims 1 to 4 wherein the first fluid is configured to flow towards the first range from the second range.

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