JPS62147296A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To permit to distribute the flow of refrigerant uniformly and facilitate the setting of a balance among heat transfer pipes with a simple structure by a method wherein a predetermined pieces of the heat transfer pipes among the group of heat transfer pipe are provided with orifices at the inside of the opening ends thereof. CONSTITUTION:Upon room heating operation, refrigerant, whose pressure is reduced by capillary tubes 20, becomes two phases of gas and liquid and is distributed into two directions at the part of a n inlet for an outdoor side heat exchanger 19 equipped with fins 12 by a branch tube 15. Orifices 14 are provided at a part whereat the figfigerant enters into heat transfer tubes 13 from the branch tube 15, therefore, the dynamic pressure of the refrigerant is converted into a static pressure at this part and the refrigerant tries to flow uniformly into two pieces of heat transfer tubes. The resistances of the orifices 14 are changed in respective heat transfer tubes 13, therefore, the difference of flow resistances of respective heat transfer tubes themselves are cancelled by these orifices. Thus, the refrigerant of two phases may be distributed uniformly to flow through respective heat transfer tubes.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a finned heat exchanger that equalizes the divided flow of refrigerant in an air conditioner or the like.

2. Description of the Related Art In recent years, the performance of finned heat exchangers has been increasing, and the division of refrigerant inside the heat exchangers has also been studied. For example, in an outdoor heat exchanger during heat pump heating operation,
If the refrigerant diversion is poor, the evaporation pressure in some of the heat exchanger tubes will be low, resulting in a problem of frost forming on only a portion of the heat exchanger tubes. Therefore, methods for equalizing the distribution of refrigerant to the heat exchanger have been studied.

An example of the conventional refrigerant distribution device mentioned above will be described below with reference to the drawings.

FIG. 5 is a sectional view of a refrigerant distribution device in a conventional air conditioner, and FIG. 6 is a refrigerant piping diagram of an air conditioner using the device shown in FIG. 5 and 6, 1 is a refrigerant distribution device, 2 is a pipe connected to a heat exchanger, 3 is a pipe connected to a valve inside the outdoor unit, 4 is a capillary tube, 5 is a check valve, 6 is a compressor, 7 is a four-way valve, 8 is an outdoor heat exchanger, 9 is an indoor heat exchanger, 10 is a connection valve, and 11 is a throttle.

The operation of the refrigerant distribution device configured as described above will be described below. First, in the case of cooling operation, the high temperature and high pressure discharge gas compressed by the compressor 6 is condensed in the outdoor heat exchanger 8, passes through the refrigerant distribution device 1a, is depressurized by the throttle 11, and is reduced in pressure by the connecting valve. It reaches 10. At this time, inside the refrigerant distribution device 1a, the check valve 5 is pushed toward the valve-side piping 3 side, so a passage is opened and flow resistance is eliminated. The refrigerant whose pressure is reduced by the throttle 11 and becomes low temperature and low pressure is distributed to the indoor heat exchanger 9 by the refrigerant distribution device 1b.

At this time, the refrigerant that exits the throttle is a two-phase flow of gas-liquid mixture.

When this two-phase flow flows to the flow dividing device 1b, it pushes the check valve 5 toward the indoor heat exchanger 9 side. Therefore, a two-phase flow flows within the capillary tube 4. In this way, the divided flow to the indoor heat exchanger is made uniform (Utility Model Publication No. 5S-31275).

Problems to be Solved by the Invention However, the above configuration has the following problems.

(1) When the number of passes increases, many capillary tubes must be routed around, which requires a large amount of space.

(2) It is difficult to select a cabinet that achieves a good balance of shunt flow.

(3) Poor workability during assembly.

In view of the above-mentioned problems, the present invention provides a finned heat exchanger that has a simple structure, allows uniform distribution of refrigerant, allows easy setting of balance between heat transfer tubes, and has good workability during assembly. It is.

Means for Solving the Problems In order to solve the above problems, the present invention provides orifices inside the open ends of a predetermined number of heat transfer tubes in which a refrigerant flows. be.

Effects The present invention eliminates the need for a capillary tube due to the above-described configuration, and is structurally simple. Setting the divided flow rate is also very easy since it can be done by simply changing the orifice.

EXAMPLE Hereinafter, a finned heat exchanger according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a finned heat exchanger, and FIG. 2 is an overall view of the finned heat exchanger. In Figures 1 and 2, 1
2 is a fin, 13 is a heat exchanger tube, and 14 is an orifice.

FIG. 3 is a sectional view of the heat exchanger tube section when the pipes are connected. In the figure, 15 is a branch pipe, and 16 is a pipe.

Figure 4 shows the refrigeration cycle, where 17 is a compressor, 1
8 is a four-way valve, 19 is a finned heat exchanger on the outdoor side, 20 is a capillary tube, and 21 is a finned heat exchanger on the indoor side.

The operation of such a refrigeration cycle will be explained. First, during heating operation, the high temperature and high pressure refrigerant discharged from the compressor 17 is condensed and liquefied in the finned heat exchanger 21 on the indoor side. This liquefied refrigerant is transferred to the capillary tube 20.
The pressure is reduced at , and the refrigerant becomes a gas-liquid two-phase refrigerant. This two-phase refrigerant flows into the finned heat exchanger 19 on the outdoor side. Here, since the finned heat exchanger 19 on the outdoor side has two passes, it is necessary to divide the refrigerant into two paths. However, since the refrigerant flowing into the finned heat exchanger 19 on the outdoor side is a gas-liquid two-phase flow, if it is allowed to flow in as it is, the gas-liquid balance will be poor, and the refrigerant will not flow uniformly into each transmission pipe. . Furthermore, since the resistance differs depending on each path, the flow will not be uniformly divided if the flow is made to flow directly. Therefore, in this embodiment, an orifice 14 is provided inside the open end of the heat exchanger tube 13, as shown in FIGS. 1 to 3.

The operation will be explained using FIG. The refrigerant, which has been depressurized in the capillary tube and becomes two-phase gas-liquid, is transferred to the branch pipe 15 at the inlet of the finned heat exchanger on the outdoor side.
It is branched in the direction. Since the orifice 14 is provided at the part where the branch pipe 15 enters the heat exchanger tube 13, the dynamic pressure of the refrigerant is converted to static and positive at this part, and the refrigerant tends to flow equally into the two heat exchanger tubes. Further, since the orifice 14 has a different resistance in each heat exchanger tube 1a, the difference in flow resistance of each heat exchanger tube itself is canceled out by this orifice. In this way, the two-phase refrigerant is uniformly divided into each heat exchanger tube.

Next, the structure will be explained using FIG. 1. The refrigerant branching portion is simply an expanded portion of the heat transfer tube 13 into which an orifice 14 is inserted. By changing the diameter of this orifice, the balance between each heat transfer tube can be adjusted. In addition, this expanded tube portion also serves as a tube connection portion, similar to the conventional heat exchanger, so that piping can be brazed to this portion.

As described above, the orifice 1 is formed inside the open end of the heat exchanger tube 13.
4, it is possible to uniformly divide the refrigerant with a simple structure, the balance between the heat transfer tubes can be easily set, and workability during assembly can be improved.

In this embodiment, the heat transfer tubes 13 of the finned heat exchanger and the piping 16 are connected by a branch pipe 15, but instead of this branch pipe 15, a header or a distributor is connected.
etc. may also be used.

Effects of the Invention As described above, the present invention provides orifices inside the open ends of a predetermined number of heat exchanger tubes, thereby making it possible to uniformly divide the refrigerant with a simple structure, and to improve the flow of the refrigerant between the heat exchanger tubes. Balance can be easily set, and work efficiency during assembly can be improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of a finned heat exchanger according to an embodiment of the present invention, FIG. 2 (a> is a side view of the finned heat exchanger, and FIG. 2(b) is a front view of the same, Figure 3 is a sectional view of the heat transfer tube section when piping is read directly, Figure 4 is a diagram showing a refrigeration cycle, Figure 5 is a sectional view of a refrigerant distribution device in a conventional air conditioner, and Figure 6 is the same as in Figure 5. It is a refrigerant piping diagram of an air conditioner using the device. 12... Fins, 13... Heat exchanger tubes, 1
4... Orifice. Name of agent: Patent attorney Toshio Nakao et al. 18th
1 figure
12--- F/NO3--- Iun, 6~
51 [Figure 2 (cL) (b
Figure 3

Claims (1)

[Claims] A group of fins in which a plurality of fins are arranged in parallel at predetermined intervals, through which air flows, and a group of heat transfer tubes inserted at right angles to the group of fins, through which a refrigerant flows, A heat exchanger with fins, characterized in that an orifice is provided inside the open end side for the number of fins.