JP5404589B2 - Twisted tube heat exchanger - Google Patents

Description

  The present invention relates to a twisted tube heat exchanger for exchanging heat between water and a refrigerant, for example.

  Conventionally, in a torsion tube heat exchanger in which an outer tube is spirally wound around the outer periphery of a core tube, the tube is expanded by applying a high hydraulic pressure to the inside of the core tube, or through a dicing die inside the core tube. Expanding the tube, thereby relatively increasing the tightening force of the refrigerant tube and causing the refrigerant tube to bite into the outer peripheral surface of the core tube, thereby deforming the outer peripheral surface of the core tube into a concave shape, There is known one that can increase the heat exchange performance by increasing the contact area with the outer tube (see, for example, Patent Document 1).

  Also, by adding irregularities to the peripheral wall of the outer tube, a plurality of protrusions that protrude from the inner peripheral wall are provided, and inside the outer tube, a low-temperature layer of fluid that flows near the wall surface and flows away from the wall surface It has been proposed that heat exchange performance can be improved by causing turbulence in the temperature boundary layer formed by the high temperature layer having a relatively high temperature and by disturbing and mixing the fluid flow. (For example, refer to Patent Document 2).

Japanese Patent Laying-Open No. 2004-93057 (FIG. 3) JP 2010-1227496 A (FIGS. 1 and 2)

  Regardless of whether it is a core tube or an outer tube, a concavo-convex shape is added to the peripheral wall of the tube for the purpose of improving the heat exchange performance by increasing the turbulent flow effect and contact area. When trying to do, it is necessary to add an uneven shape before processing a plurality of spiral grooves. However, when an uneven shape is added to the tube, there is a problem that due to the effect of work hardening, abnormal deformation occurs when the tube is expanded, and the spiral groove processing cannot be performed with high accuracy.

  On the other hand, it is very difficult in manufacturing to add an uneven shape to the tube after processing a plurality of spiral grooves.

  The present invention has been made to solve the above-described problems, and a first object thereof is to make it possible to accurately form a plurality of spiral grooves on the outer periphery of a core tube.

  The second object of the present invention is to promote the turbulent effect of the fluid flowing inside the core tube and improve the heat transfer performance.

Torsion tube type heat exchanger according to the present invention, comprising a core tube having a helical groove of plural rows outside circumference, and the outer pipe of the plurality of which are wound along a spiral groove of the core tube, the In the twisted tube heat exchanger , the core tube is composed of a phosphorus deoxidized copper tube, and a plurality of spiral inner grooves are formed on the inner peripheral wall, and the groove width dimension of the spiral inner groove of the core tube T, the height of the spiral inner groove of the core tube is h, and the outer diameter of the outer tube is Ro, the groove width dimension t and the height dimension h of the spiral inner groove of the core tube are: This is set in a range where the relationship of h <t <(Ro / 4) is established.

In the torsion pipe type heat exchanger according to the present invention, the core tube is formed of a phosphorus deoxidized copper tube, on its inner peripheral wall is formed with a spiral inner surface grooves of plural rows, spirally of the core tube The groove width dimension of the inner groove of the core pipe is t, the height dimension of the spiral inner groove of the core pipe is h, and the outer diameter dimension of the outer pipe is Ro. And the height dimension h are set in a range in which the relationship of h <t <(Ro / 4) is established, so that the contact area with the insertion tool at the time of twisting for providing a plurality of spiral grooves is reduced. be able to. For this reason, the trouble wound around the insertion tool can be greatly reduced, and a plurality of spiral grooves can be accurately formed on the outer periphery of the core tube.
Moreover, the inner surface groove | channel of a core pipe can increase the turbulent effect of the fluid which flows through the inside of a core pipe, and can improve heat exchange performance.
Moreover, the height dimension h of the inner surface spiral groove can be controlled to an appropriate groove height dimension, and an increase in pressure loss of the fluid flowing inside the core tube can be suppressed.

It is sectional drawing which cut | disconnects and shows the twisted tube type heat exchanger which concerns on Embodiment 1 of this invention along the tube axis | shaft of a core tube. It is an expanded sectional view of the A section of FIG. It is sectional drawing which cut | disconnects and shows the core pipe of the core pipe of the twisted tube type heat exchanger which concerns on Embodiment 1 of this invention in the direction orthogonal to a pipe axis. It is a schematic diagram for demonstrating the lead angle (alpha) of the inner surface groove | channel of the core pipe of the twisted tube type heat exchanger which concerns on Embodiment 1 of this invention. It is sectional drawing which cut | disconnects and shows the core pipe of the core pipe of the twisted tube type heat exchanger which concerns on Embodiment 2 of this invention in the direction orthogonal to a pipe axis. It is sectional drawing which cut | disconnects and shows the torsion pipe | tube type heat exchanger which concerns on Embodiment 2 of this invention along the pipe axis of a core pipe. It is an expanded sectional view of the B section of FIG.

Embodiment 1. FIG.
The present invention will be described below with reference to illustrated embodiments.
1 is a cross-sectional view showing a twisted tube heat exchanger according to Embodiment 1 of the present invention cut along the tube axis of a core tube, FIG. 2 is an enlarged cross-sectional view of part A in FIG. 1, and FIG. FIG. 4 is a schematic view for explaining the lead angle α of the inner surface groove of the core tube. FIG. 4 is a cross-sectional view showing the core tube of the core tube cut in a direction perpendicular to the tube axis.

  The torsion tube heat exchanger 1 according to the present embodiment includes a phosphorous deoxidized copper core tube 2A through which water (fluid A) flows, as shown in FIG. 1, and carbon dioxide (fluid B), which is a refrigerant inside. Is composed mainly of a plurality of (for example, three) outer pipes 3 through which the air flows. That is, the torsion tube heat exchanger 1 is assembled by winding three outer tubes 3a, 3b, 3c along a plurality of (for example, three) spiral grooves provided on the outer periphery of the core tube 2A. This is a heat exchanger in which the tube 10A is further formed into an elliptical coil shape.

  The outer tube 3 is divided into the outer tubes 3a, 3b, and 3c at the core tube 2A portion, but is joined before and after the core tube 2A and connected to a refrigerant circuit (not shown) to circulate the refrigerant. In the following description, the outer tubes 3a, 3b, and 3c are collectively referred to as “outer tube 3”.

  The core tube 2A is also connected to a device (not shown) outside the device in which the torsion tube heat exchanger 1 is accommodated, and circulates water between the torsion tube heat exchanger 1 and an external device. It is.

  2 A of core pipes are attached to piping which extended the connection port and valve | bulb for taking out to the exterior of the apparatus in which the twisted tube type heat exchanger 1 is accommodated. For example, in the case of a heat pump type hot water heater, a phosphorus deoxidized copper pipe that has good thermal conductivity and can be easily brazed and bent is generally used for pipes and parts connected to the pipes. When the core tube 2A is a steel tube or a SUS tube, brazing with a phosphorous deoxidized copper tube is not easy, and the base tube (in this case, a steel tube or a SUS tube serving as a core tube) is hard. It is not easy to further process the assembly tube formed by winding 3 into an elliptical coil shape, and the thermal conductivity is also poor. Therefore, here, as the core tube 2A used for the torsion tube heat exchanger, a phosphorus deoxidized copper tube having good thermal conductivity and easy brazing and bending with other piping and piping parts is used.

  The core tube 2A is manufactured by fixing both ends of a phosphorus-deoxidized copper smooth tube and inserting a mandrel on the inner diameter side and applying a twisting process without pressing a tool against the outer surface of the tube. Therefore, the inner diameter of the core tube 2A is determined by the mandrel diameter.

  The height H of the crest at the bottom of the valley that forms the spiral groove on the outer periphery of the core tube 2A is higher than the half of the outer diameter Ro of the outer tube 3 as shown in FIG. It is set to a range ((Ro / 2) <H ≦ Ro) that is not more than the dimension Ro. As described above, the outer tube is wound along the spiral groove formed by the valley shape in which the peak height dimension of the specific range is provided at the pitch of the specific range on the outer periphery of the core tube 2A. The outer tube can be stably wound and fixed in place at a predetermined position, and is effective in suppressing excessive flattening of the outer tube 3 and preventing buckling.

  Further, on the inner peripheral wall of the core tube 2A, as shown in FIGS. 3 and 4, a spiral inner surface groove (hereinafter, referred to as a core tube 2A below) from the stage of the raw tube before twisting by the mandrel (after processing becomes the core tube 2A) 5A. 4 is formed over the entire area. The inner surface spiral groove 4 has a lead angle α set in a range of 0 ° <α ≦ 30 °. Further, the inner surface spiral groove 4 has a height dimension h so that the groove width dimension t of the inner surface spiral groove 4 is smaller than 1/4 of the outer diameter dimension Ro of the outer tube 3. Are set so as to be smaller than the groove width dimension t (h <t <(Ro / 4)). As a result, the contact area with the mandrel during twisting by the mandrel is reduced, and the frictional force with the mandrel generated during twisting can be reduced. Therefore, it is possible to greatly reduce the winding trouble with the mandrel that occurs during the twisting process, and to improve the manufacturing efficiency.

  In addition, since the frictional force with the mandrel generated during twisting can be reduced, the number of mandrel detachment and reverse rotation torsion performed during twisting can be reduced, leading to improved productivity and a valley-bottom spiral due to reverse rotation. Shape collapse can be suppressed.

  Moreover, since the spiral groove shape formed by this mandrel generates a turbulent flow of water flowing inside the core tube, the heat exchange performance is improved. Furthermore, in this embodiment, since the inner surface spiral groove 4 is formed on the inner peripheral wall of the core tube 2 from the stage of the raw tube 5, the turbulent flow effect of the water flowing inside the core tube can be further increased. It is possible to improve the heat exchange performance.

  Further, by making the height dimension h of the inner spiral groove 4 smaller than the groove width dimension t, it can be controlled to an appropriate groove height dimension, and it is possible to suppress an increase in pressure loss of water flowing inside the core tube. it can.

  As described above, according to the twisted tube heat exchanger of the first embodiment, the turbulent flow effect can be promoted and the heat transfer performance can be improved without providing a plurality of irregularities (dimples) on the outer tube portion. Further, the inner surface spiral groove 4 formed from the stage of the raw tube 5 on the inner peripheral wall of the core tube 2 reduces the contact area with the mandrel, thereby improving the productivity and suppressing the crest of the bottom of the mountain valley. it can.

Embodiment 2. FIG.
In the first embodiment described above, an example in which the inner spiral groove 4 is formed over the entire inner peripheral wall of the core tube has been described as an example. Next, the slope of the crest of the outer spiral groove is acute and the groove portion flows in the core tube. Embodiment 2 in which the inner surface spiral groove 4 is formed only at the bottom of the valley when greatly concerned with the pressure loss of water will be described.

  FIG. 5 is a cross-sectional view showing a core tube of a twisted tube heat exchanger according to Embodiment 2 of the present invention cut in a direction perpendicular to the tube axis, and FIG. 6 is cut along the tube axis of the core tube. FIG. 7 is an enlarged cross-sectional view of a portion B in FIG. 6. In each figure, the same parts as those of the first embodiment are denoted by the same reference numerals. Here, the material of the core tube (phosphorus deoxidized copper) and the specifications of the outer peripheral spiral groove and inner spiral groove formed on the core tube (excluding the number of inner spiral grooves) are described in the first embodiment. It is assumed that they are the same as those described above, and the description thereof is omitted.

  In the torsion tube heat exchanger of the second embodiment, when three spiral grooves are formed on the outer periphery of the core tube 2B as shown in FIG. 6, the valley bottoms exist every 120 degrees in the circumferential direction. The inner surface spiral groove 4 is formed only at the bottom of the valley. That is, the inner surface spiral groove forming position of the raw pipe 5B composed of a phosphorus-deoxidized copper smooth tube is specified in advance, and the inner surface spiral groove is formed (FIG. 5). Then, both ends of the raw tube 5B are fixed, and a mandrel is inserted on the inner diameter side without applying a tool to the outer surface of the tube, and twisting is performed, so that there are three spiral grooves on the outer periphery. The core tube 2B in which the inner spiral groove 4 is formed only at the bottom of the valley is manufactured. Therefore, the inner diameter of the core tube 2B is also determined by the mandrel diameter. Further, the number of the inner spiral grooves 4 is determined by the width dimension of the valley bottom of the outer peripheral spiral groove.

  After that, three outer tubes 3a, 3b, 3c are wound along the three spiral grooves provided on the outer periphery of the core tube 2B to create an assembled tube 10B (FIG. 6). It is formed in an elliptical coil shape.

  As described above, in the twisted tube heat exchanger according to the second embodiment, the inner spiral groove 4 is formed only along the bottom of the outer spiral groove, and the inner spiral groove 4 is formed at the peak of the outer spiral groove. It has not been. Therefore, it is possible to suppress an increase in the pressure loss of the water flowing inside the core tube regardless of the shape of the peak portion of the outer peripheral spiral groove.

  1 torsion tube heat exchanger, 2A, 2B core tube, 3, 3a, 3b, 3c outer tube, 4 inner surface spiral groove (core tube inner surface groove), α inner surface groove lead angle, t inner surface groove width dimension , H Height of inner groove, outer diameter of Ro outer tube.

Claims (6)

A core tube having a plurality of spiral grooves on the outer periphery;
In a twisted tube heat exchanger comprising a plurality of outer tubes wound along the spiral groove of the core tube,
The core tube is
It is composed of a phosphorus deoxidized copper tube, and a plurality of spiral inner grooves are formed on the inner peripheral wall ,
When the groove width dimension of the spiral inner groove of the core tube is t, the height dimension of the spiral inner groove of the core tube is h, and the outer diameter dimension of the outer tube is Ro, the spiral of the core tube The torsion tube heat exchanger is characterized in that the groove width dimension t and the height dimension h of the internal groove are set in a range where the relationship of h <t <(Ro / 4) is established. Helical inner surface grooves of the core tube is formed every 120 degrees, torsion tube according to claim 1, wherein the number of threads is characterized in that it is determined by the width of the root portion of the spiral groove of the outer peripheral Shape heat exchanger. A core tube having a plurality of spiral grooves on the outer periphery;
In a twisted tube heat exchanger comprising a plurality of outer tubes wound along the spiral groove of the core tube,
The core tube is
It is composed of a phosphorus deoxidized copper tube, and a plurality of spiral inner grooves are formed on the inner peripheral wall,
Helical inner surface grooves of the core tube is formed every 120 degrees, the number of threads is that torsional Ri tubular heat exchanger you wherein being determined by the width of the root portion of the spiral groove of the outer peripheral vessel. The core tube according to claim 1 to 3 in which said the inner surface groove is phosphorus deoxidized copper tube formed in the inner circumferential wall in advance, is provided with a helical groove of said plural rows Torsion tube heat exchanger. The twisted tube heat exchanger according to any one of claims 1 to 4, wherein a plurality of spiral grooves on an outer periphery of the core tube are formed by passing a mandrel through an inner surface of the tube. Wherein the lead angle alpha helical inner grooved, 0 ° <torsional tubular heat exchanger according to any one of claims 1-5, characterized in that it is set to a range of alpha ≦ 30 °.

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