JPH04158192A - Heat exchanger - Google Patents

Abstract

PURPOSE:To prevent a clogging of a gas flow passage caused by a film-like flow from being generated and make a substantial reduction of noise caused by an intermittent opening or closing of the gas flow passage by a method wherein a plurality of flow liquid grooves wider than that of heat transferring groove are formed in a spaced-apart relation in a circumferential direction at an inner surface of each of curved lines in a heat exchanger having bent connection pipes. CONSTITUTION:Cylinders 18 are formed at both ends of a connection pipe 16. Each of linear line portions 10A of a heat transferring pipe 10 is inserted into these cylinders 18 and fixed there. Since a plurality of flow liquid grooves 14 having wider width than that of a helical groove 12 and extending along an axial direction are formed within a curved line part 10B of a heat transferring pipe 10, refrigerant flows along each of the flow liquid grooves 14 having wider width and thus a uniform film-like flow clogging the inside part of the curved line 10B is not formed. A width of each of the flow liquid grooves 14 is wider than that of the helical groove 12 and preferably about 3 to 30% of an inner diameter of the heat transferring pipe 10. A depth of each of the flow liquid grooves 14 is the same or slightly deeper than that of the helical groove 12 and the bottom surface of each of the flow liquid grooves 14 is made flat and smooth. When the film-like flow or the gas flow is intermittently broken, the noise generated during this operation can be substantially reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a heat exchange device used in an air conditioner, an electric refrigerator, etc., and particularly relates to an improvement for reducing noise during use.

``Prior Art J'' FIG. 15 is a partial front view showing a heat exchange device commonly used in air conditioners, electric refrigerators, etc.

Reference numeral 1 in the figure is a U-shaped heat exchanger tube, which includes a pair of parallel straight parts IA and a curved part IB connecting one end side of these straight parts IA.
and has.

The open end of each adjacent heat exchanger tube l is connected to a short U-shaped connecting tube 2.
The heat exchanger tubes 1 and the connecting tubes 2 constitute one flow path with both ends open. Further, a large number of cooling fins 4 made of thin metal plates are fixed vertically to the straight portion IA of the heat transfer tube 1 at regular intervals.

To fix the cooling fins 4, the straight portions IA of each heat transfer tube I are passed through the insertion holes (paths shown in the figure) formed in the cooling fins 4 before connecting the connecting tubes 2.

Next, tube expansion plugs are pushed into the straight portions IA from the open ends of the straight portions IA, the outer diameter of the straight portions IA is expanded, and each cooling fin 4 is fixed. After fixing the cooling fins 4, the connecting pipe 2 is fixed to obtain a product.

By the way, in conventional heat exchange equipment, a metal tube with a smooth inner surface was used as the heat transfer tube l, but recently, spiral or linear heat transfer grooves have been formed on the inner surface of the metal tube by rolling or drawing. It has begun to be used in large numbers. According to such a heat transfer tube with heat transfer grooves, the following effects can be obtained.

■ When this heat transfer tube is used as a condensing tube, the heat medium vapor flowing inside the condensing tube is made into a turbulent flow by the ridges between the heat transfer grooves, and the ridges are used as condensation nuclei to condense the heat medium vapor. Enhances effectiveness and promotes liquefaction.

Further, the condensed heat medium liquid is efficiently flowed in the longitudinal direction of the heat transfer tube due to the surface tension within the heat transfer groove, thereby increasing the reflux effect.

(2) When used as an evaporation tube, the edges of the heat transfer grooves act as evaporation sections for generating bubbles, promoting boiling and improving the vaporization efficiency of the heat medium liquid supplied into the heat transfer tube. Due to the surface tension within the heat transfer groove, the heat transfer liquid flows in the longitudinal direction of the heat transfer tube and is uniformly dispersed on the inner surface of the heat transfer tube.

-Problem to be solved by the invention- By the way, in a heat exchange device using an F-neck heat exchanger tube with such heat transfer grooves formed, a new noise problem may arise, which is not a problem with a heat exchanger tube with a smooth inner surface. It turned out that. When this type of heat transfer tube with heat transfer grooves is used, especially as a refrigerant evaporation section, the refrigerant flowing inside the heat transfer tube 1 may generate unexpectedly loud flowing sound at the curved section IB, which may cause problems in the entire device. The amount of noise reaches a level that cannot be ignored.

Therefore, the present inventors conducted a detailed study on the mechanism of noise generation and came to the following findings.

FIG. 16 is an explanatory diagram thereof. Note that the inner groove of the heat exchanger tube 1 is omitted in this figure. When the refrigerant flowing in the straight portion IA reaches the curve NIH, the flow becomes wider due to the influence of the heat transfer groove. Then, this wide flow flows down along the inner circumferential wall surface of the curved portion IB, forming a late autumn liquid flow 6 that partitions the inside of the heat exchanger tube I. On the other hand, the refrigerant vapor flowing together with the refrigerant in the heat transfer tube 1 is once blocked by the liquid flow 6 in late autumn, and then intermittently breaks the liquid flow 6 and flows downstream, generating sound at that time. Since this noise is generated intermittently at each curved portion IB, the amount of noise in the entire device cannot be ignored.

"Means for Solving the Problems" The present invention was made to solve the above problems;
The heat transfer tube is characterized in that a plurality of liquid flow grooves extending in the axial direction of the curved portion and having a width larger than the heat transfer grooves are formed at intervals in the circumferential direction on the inner surface of the curved portion of the heat transfer tube.

Note that the heat transfer groove formed on the inner surface of the heat transfer tube may be composed of two types of spiral grooves that intersect with each other at a certain angle.

"Function" In the heat exchange device of the present invention, within the curved part of the heat exchanger tube,
In addition to the heat transfer grooves, there are also multiple liquid flow grooves that are wider than the heat transfer grooves, and the refrigerant mainly flows separately along each of the flow grooves, creating a cold late autumn flow inside the heat transfer tube. It never forms.

Therefore, the gas flow path is not blocked due to the late autumn flow, and the noise caused by the intermittent opening and closing of the gas flow path can be significantly reduced.

Embodiment FIGS. 1 to 4 are diagrams showing an embodiment of a heat exchange device according to the present invention.

This heat exchange device includes a plurality of heat exchanger tubes 10 consisting of a pair of parallel straight portions 10A and curved portions 10B, and a U-shaped connecting tube 16 (see FIG. 3) that connects adjacent ends of these heat exchanger tubes 10. ) and a large number of cooling fins (not shown) fixed perpendicularly to each straight section 10A.

As shown in FIGS. 1 and 2, on the inner surface of the heat exchanger tube 10, there are
A large number of fine spiral grooves (heat transfer grooves) 12 parallel to each other are formed. The dimensions of these spiral grooves 12 are as follows:
Although it varies depending on the inner diameter of O, for example, the outer diameter is 10JIJI.
When applying a general-purpose heat exchanger tube of about 100 yen, the groove bottom width should be 0.
15-0.30am, preferably 0.20-0.25z
x, N height 0.10-0.30xm, preferably 016
~0.2011. Within this range, the heat transfer performance will be the highest.

In addition, on the inner surface of the heat exchanger tube IO, there are a plurality of liquid flow grooves 14 extending in the axial direction of the heat exchanger tube IO at equal intervals in the circumferential direction over the entire length of the straight portion 10A and the curved portion JOB. book) is formed. The number of these liquid flow grooves 14 is determined according to the inner diameter of the heat transfer tube 10, and in reality, it is 4 to 4.
Approximately 8 or so is suitable.

The width of the liquid flow groove 14 is larger than that of the spiral groove 12, and is preferably 3 to 30% of the inner diameter of the heat exchanger tube IO.

If it is less than 3%, the amount of refrigerant flowing through this liquid flow groove 14 will be reduced, and the effect will be weakened. Moreover, if it is larger than 30%, the liquid flow groove 14 will be too wide, and the flow of the refrigerant will spread, creating a risk that a late autumn flow will be formed.

The depth of the liquid flow groove 14 is equal to or slightly deeper than the spiral groove 12, and the bottom surface of the liquid flow groove 14 is smooth.

There are roughly two methods for manufacturing such a heat exchanger tube IO. One method is to form a spiral groove 12 on the inner surface of a metal tube by drawing or the like, and then form a linear liquid flow groove 14 on the inner surface of the metal tube by further drawing. As a result, the spiral groove 12 is crushed in the portion where the liquid flow groove 14 is formed.

The other method is to use electric resistance stitching. That is,
After forming a large number of parallel grooves on the surface of a long, flat metal plate with a constant width by rolling, the grooves are inclined with respect to the longitudinal direction of the plate. An extending liquid flow groove 14 is formed. Then, this plate material is passed through an electric resistance welding tube device, rolled into a tube shape, and the butted edges are welded to produce a heat exchanger tube.

In either case, the obtained straight heat exchanger tube is bent into a U-shape by applying it to a forming device to form a heat exchanger tube IO as shown in the figure.

On the other hand, FIGS. 3 and 4 show the connecting pipe I6, and in this embodiment, four liquid flow grooves 20 are also formed inside the connecting pipe 16. No spiral grooves are formed. The dimensions of the liquid flow groove 20 may be the same as those of the liquid flow groove 14 described above.

Cylindrical portions 18 with enlarged diameters are formed at both ends of the connecting tube 16, and the straight portions 10A of the heat transfer tubes 10 are respectively inserted into these cylindrical portions I8 and fixed by means such as brazing.

According to the heat exchange device having the above configuration, a plurality of flow grooves I4 which are wider than the spiral grooves 12 and extend along the axial direction are formed in the curved portion 10B of the heat exchanger tube IO, so that the refrigerant The liquid flows separately along each of the wide liquid flow grooves 14, and does not form a late autumn flow that blocks the inside of the curved portion 10B. Therefore, the gas flow path is not blocked by the late autumn flow, and the noise generated when the gas flow blocked by the late autumn flow intermittently breaks through the late autumn flow can be significantly reduced.

In addition, in this example, a liquid flow groove 14 is also provided inside the straight portion 10A.
is formed, it is possible to improve the transportability of the refrigerant in the axial direction within the straight portion 10A while ensuring the heat transfer performance improvement effect of the spiral groove I2, and the heat exchange efficiency is increased accordingly. .

Furthermore, in this example, a flow groove 20 is also provided on the inner surface of the connecting pipe 16.
Since this is formed, it is possible to prevent the gas flow path from being blocked by the late autumn liquid flow even within the connecting pipe 16, and the noise can be reduced accordingly.

Next, FIGS. 5 and 6 are diagrams showing a second embodiment of the present invention.

In the heat exchange device of this second embodiment, on the inner surface of the heat exchanger tube 10,
In addition to forming a large number of spiral main grooves 22 and sub-grooves 24 that intersect with each other, these grooves 22 and 24 that intersect with each other are formed.
It is characterized in that a liquid flow groove 14 is formed from above. The other configurations are the same as in the first embodiment.

As shown in FIGS. 6 to 11, the opening width of each main groove 22 is narrowed between the intersections of each main groove 22 and the sub groove 24, and a tubular portion 26 having an elongated opening is formed. It has become.

The metal tube 1 is made of a conventionally used material such as copper, copper alloy, or aluminum, and its wall thickness, diameter, etc. can be determined depending on the application. In this example, as shown in FIG. 5, a flat belt-shaped welded portion 28 extending in the axial direction is formed on the inner surface of the heat exchanger tube IO. As will be described later, this heat exchanger tube 10 is manufactured by electric resistance welding, and this welded portion 28 also performs the same function as the liquid flow groove 14, although the effect is inferior.

The cross-sectional shape of the main groove 22 is U-shaped before deformation. In this way, it is easier to form the main groove 22 into a tubular shape by narrowing the opening width of the main groove 22, which is closer to the U-shape. In the case of normal heat exchanger tubes, main groove 2
The preferred size range for No. 2 is as follows.

Depth of main groove 22. 0.2~0.3xy, width of 1 main groove 22: 02~05■, pitch of main groove 22, 0.4~1.5x shoulder, cross-sectional angle of bottom of main groove 22 75° or more.

On the other hand, the sub-groove 24 is formed to have a V-shaped cross section.

The pitch of the sub-grooves 24 may be equal to the pitch of the main grooves 22, but does not necessarily have to be equal. In the case of a normal heat exchanger tube, the dimensions of the sub-groove 24 are preferably within the following range).

Depth of sub-groove 24, 005 to 0.31st order, pitch 0.1
-1.5im, the cross-sectional angle change of ~' character is about 45 to 90 degrees.

Note that the intersection angle between the main groove 22 and the sub groove 24 is lO~60°.
, especially the force that is 30-40°? desirable. 10-6
Outside the 0° range, it becomes difficult to form the tubular portion 26. Moreover, it is desirable that the main groove 22 is within 30 degrees with respect to the axial direction of the heat exchanger tube IO). From this, in dogs, heat transfer tube I
The flow of the heat medium liquid in the axial direction of O becomes poor.

Next, FIG. 12 is a diagram showing a method of manufacturing this heat exchanger tube. First, the plate material lO that will become the heat exchanger tube is continuously rolled by the 10th rule R1 and the 20th rule R2, the main groove 22 is formed by the 10th rule R1, and the minor groove 24 is
After sequentially forming the grooves 14, the flow grooves 14 are further formed using the 30th rule R3.

As shown in FIG. 13, on the outer peripheral surface of No. 10-R1,
A large number of protrusions 30 having a U-shaped cross section for forming the main grooves 22 are formed so as to be inclined at a certain angle with respect to the circumferential direction of the roll R1.

On the other hand, as shown in FIG. 14, a large number of parallel protrusions 32 having a V-shaped cross section are formed on the outer peripheral surface of the 20th rule R2. These protrusions 32 are 10th in the circumferential direction of the roll R2.
- It is inclined in the opposite direction to R1.

Note that the space between the protrusions 32 of the 20th rule R2 may be curved as shown by the dotted chain line 34 in FIG. In this way, when forming the sub-groove 24, the side wall portion of the main groove 22 is smoothly deformed along the curved surface 34, increasing the effect of narrowing the opening width of the main groove 22. Second, a narrow flat portion may be formed at the tip of each protrusion 32, as shown by reference numeral 36.

A plurality of protrusions are formed on the outer circumferential surface of the 30th rule R3 in the circumferential direction, and by rolling the strip material 10 with this 30th rule R3, a liquid flow groove 14 is formed. be done.

After rolling in three stages, the strip material 10 is introduced into the electric resistance welding machine with the grooved surface facing the inner surface, passed between forming rolls in multiple stages, and the strip material 10 is rolled in the width direction. Finally, both side edges of the plate material IO are welded and formed into a circular tube shape.

Thereafter, the welded portion on the outer circumferential surface of the tube is shaped as necessary, and then the tube is wound into a roll or cut to a predetermined length and bent into a U-shape to obtain a heat exchanger tube IO. Note that the method for manufacturing the heat exchanger tube 10 is not limited to the above method, and may be formed by drawing or the like.

When such a heat exchanger tube IO is used, the intersecting grooves 22, 24 further increase the refrigerant transport power, so the refrigerant tends to spread uniformly along the inner surface of the curved portion 10B within the curved portion 10B. is further increased compared to the case of a single spiral groove. For this reason, compared to a heat exchanger tube with a simple spiral groove, late autumn flow is more likely to occur along the curved part IO.
It is thought that the noise problem will become even more pronounced.

However, in this example, the liquid groove! 4 is formed on the inner surface of the curved portion 10B, the refrigerant spreading along the intersecting grooves 22 and 24 flows into each liquid flow groove 14, and is divided into a plurality of flows along each liquid flow groove 14 and flows out of the curved portion. Pass JOB. As a result, late fall flows that block the liquid flow path in the curved portion 10B are less likely to occur, and noise caused by this liquid flow can be reduced.

In addition, in this embodiment, since each main groove 22 is formed with a large number of tubular portions 26 having relatively narrow opening widths, the inner surface Air bubbles are more likely to occur inside each tubular portion 26 than in the case of a smooth heat exchanger tube or a simply grooved heat exchanger tube. This one
As a result, these bubbles act as nuclei and promote evaporation, thereby significantly increasing the vaporization efficiency of heat transfer liquid such as fluorocarbon.

In addition, since the tubular portions 26 are provided intermittently, the heat medium liquid that has flowed into each main groove 22 receives surface tension from the inner surface of the tubular portion 26 and quickly moves along the main groove 22 due to capillarity. transported. Therefore, the transport efficiency of the heat medium liquid is improved compared to the case of a simple grooved heat exchanger tube.

Furthermore, the inner area of the heat exchanger tube 10 is increased compared to a simple grooved heat exchanger tube, and the edges of the grooves 22 and 24 are sharp, so that the surface activity is high. From this point on, the condensation of the medium vapor can be promoted and the liquefaction efficiency can be increased.

In each of the above embodiments, the shape of the heat transfer tube is not limited to a circular cross section, but the present invention can be implemented with an elliptical cross section, a flat tubular shape, etc. However, the shape etc. of the cooling fins may be changed arbitrarily, and depending on the case, it is possible to configure the cooling fins without providing them.

However, it is also possible to form the liquid flow groove 14 only on the inner surface of the curved portion 10B, and there is no need to provide the liquid flow groove inside the connecting pipe.

Effects of the Invention, 1 As explained above, according to the heat exchange device according to the present invention, there is a flowing liquid groove in the curved portion of the heat transfer tube that is wider than the heat transfer groove and further extends along the axial direction. Since a plurality of grooves are formed, the refrigerant flows separately along each of the wide flow grooves, and does not form a cold flow inside the curved portion. However, the gas flow path is not blocked by the late autumn flow, and the noise generated when the gas flow blocked by the late autumn flow intermittently breaks through the late autumn flow can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are a vertical cross-sectional view showing a heat exchanger tube of a heat exchange device according to a first embodiment of the present invention, and a cross-sectional view along the line ■-■.
Figures 4 and 4 are a vertical cross-sectional view and a perspective cross-sectional view taken along the line ■-IV of the same embodiment, respectively. An enlarged view showing the properties of the inner surface of the heat exchanger tube, FIGS. 7 to 11 are sectional views taken along the line A-A-E-E in FIG. 6, and FIG. 12 is a diagram showing the manufacturing of the heat exchanger tube of the second embodiment Explanatory drawings showing the method, FIG. 13 and FIG. 14 are explanatory drawings of forming rolls used in the manufacturing method. On the other hand, FIG. 15 is a front view showing a general heat exchange device, and FIG. 16 is a longitudinal sectional view of a heat exchanger tube showing problems in the prior art. lO... Heat transfer tube, IOA... Straight section, IOB... Curved section, 12... Spiral groove (heat transfer groove), 14 Liquid flow groove, 16
・Connection pipe, 20 Flow groove, 22.24 Intersecting groove (
heat transfer groove), 26... tubular section, 28. welded section.

Claims (2)

[Claims] (1) A plurality of heat exchanger tubes consisting of a pair of parallel straight parts and a curved part connecting one end of these straight parts, each of which has a large number of heat transfer grooves formed on its inner surface, and each of the adjacent heat exchanger tubes. In a heat exchange device comprising bent connecting pipes that connect the open ends of the pipes to each other to form a continuous flow path, the inner surface of each curved part has a pipe extending in the axial direction of the curved part, A heat exchange device characterized in that a plurality of fluid flow grooves having a width larger than the heat grooves are formed at intervals in the circumferential direction. (2) The heat exchange device according to claim 1, wherein the heat transfer groove is constituted by two types of spiral grooves that intersect with each other.