JPH05332642A - Cross fin tube type heat exchanger - Google Patents

Abstract

PURPOSE:To provide a cross fin tube type heat exchanger used in an outdoor heat exchanger in which a clogging caused by frosting at an air flowing-in part is hardly produced and to extend an operating time until a defrosting time by a method wherein a part of the heat exchanger at the upper-most upstream side is constructed in such a manner that it may be freely moved. CONSTITUTION:In a cross fin tube type heat exchanger in which many fins 2 are fixed to a group of heat transfer pipes 1 arranged in rows in a vertical direction against an air flow 4 in such a manner that they are arranged in perpendicular to an axis of each of the heat transfer pipes and in parallel with the air flow 4, a group of fins 2 of the heat exchanger at the upper-most upstream side in respect to the flowing air 4 are set to have a specified pitch and V-shaped recesses are arranged at the extremity ends of the fins. Then, the dampers 7 which can be opened or closed are fixed at the extremity ends of the fins so as to close the recesses. Then, after advancing of the frosting, the damper 7 is opened to enable a sufficient amount of air to be flowed into the heat exchanger placed at the downstream end where the frosting is not well developed and further deterioration of performance of heat exchanging operation is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross fin tube type heat exchanger used for a heat pump type room air conditioner and the like, and more particularly to a heat exchanger suitable for frosting an outdoor heat exchanger.

[0002]

2. Description of the Related Art There are the following publicly known methods for delaying frost formation at the leading edge of fins and preventing clogging to prolong the operation time until defrosting operation is required. That is, a method of arranging a plurality of small holes in a row in the vicinity of the tip of the fin (for example, Japanese Utility Model Publication No. 62-258997), a method of arranging fins in which the air inflow surface is unevenly cut (for example, the actual development 61-29692), an example in which a heat transfer tube is eccentric to the air downstream side and stagger fins are attached (for example, JP-A-63-63).
-220094).

[0003]

However, in the prior art, when the fins upstream of the air flow of the heat exchanger are clogged due to frost, the air is blown even if the downstream heat exchanger is not yet frosted. There is a problem that the inflow is reduced, the overall heat exchange performance is deteriorated, and the operation time until the defrosting operation is started is shortened.

An object of the present invention is to provide a heat exchanger for a heat pump which is resistant to clogging due to frost formation.

[0005]

[Means for Solving the Problems] In order to solve the above problems, a structure in which a part of the heat exchanger on the most upstream side can be moved with respect to the air flow is not affected by frost formation. The structure is such that a new air inflow surface is created.

[0006]

With the above construction, even if frost is formed on the front surface of the fin, air can be sent to the heat exchanger on the downstream side and the downstream side of the heat transfer tube from the new inflow surface with a small amount of frost. Further, since the frost formation actively progresses in the heat exchanger on the upstream side with respect to the air flow, it is possible to prevent the heat exchange performance from deteriorating due to the decrease in the air volume in the heat exchanger on the downstream side. Further, the operating time until the defrosting operation is started can be lengthened without significantly deteriorating the heat exchange performance.

[0007]

EXAMPLE An example of the present invention will be described below. FIG. 1 is a perspective view of this embodiment, and FIG. 2 is a sectional view perpendicular to the tube axis of the heat exchanger of this embodiment. The heat transfer tubes 1 are arranged in a plurality of rows in a direction perpendicular to the air flow, and the fins 2 are perpendicular to the heat transfer tube axis.
The fin collars 3 are arranged parallel to the air flow 4 at regular intervals and are in thermal contact with the heat transfer tubes 1. In this embodiment, the fin group of the heat exchanger 5 on the most upstream side with respect to the inflowing air 4 is provided with a constant pitch, and a V-shaped notch is provided at the fin tip. The fin tip end portion is formed so as to close this notch. A damper 7 is attached so that it can be opened and closed. After the frost formation has progressed, the damper 7 is opened to allow air to flow into the groove. The damper can be opened / closed by a method using a shape memory alloy spring or a link opening / closing mechanism.

Another embodiment will be described with reference to FIGS. 3A, 3B and 4. FIG. 3 is a sectional view perpendicular to the tube axis of this embodiment, and FIG. 4 is a detailed view of the fin mounting portion. The refrigerant heat transfer tube 1 is inserted into an outer cylinder 8 having a length substantially equal to the axial direction of the tube, and a medium 9 having good heat conductivity and low temperature fluidity is sealed in a gap between the outer cylinder and the heat transfer tube to transfer the heat. A seal mechanism is provided that enables rotation of the heat tube and prevents the medium enclosed from leaking from both ends thereof. A block 10 having a structure in which the fin collar portion 3 is brought into thermal contact with the outer cylinder, and the fins contacting each heat transfer tube are independent fins as shown in FIG. 3A, and the fin group is rotatable around the heat transfer tube. A heat exchanger in which a plurality of stages are connected in the vertical direction is arranged on the most upstream side with respect to the air flow. When such a heat exchanger is used, as shown in FIG. 3 (b), even if frost forms on the front surface of the fins, a gap is created between the blocks by rotating each block 10 around the heat transfer tubes, Air can be delivered to the flow and downstream heat exchangers. The rotation of the block is possible by using a motor and a link mechanism.

Another embodiment will be described with reference to FIGS. 5 (a), 5 (b) and FIG. FIG. 5 is a perspective view of the heat exchanger with independent fins, and FIG. 6 is a sectional view perpendicular to the tube axis thereof.

The fin collar 3 is firmly brought into contact with the heat transfer tube 1, and blocks 10 having independent fin groups arranged at regular intervals in the tube axis direction are vertically laminated as shown in FIG. 6 (a).
A plurality of independent refrigerant circuits are connected to each other so that at least one set of refrigerant circuits has a movable structure. The heat exchanger having such a configuration is arranged on the most upstream side with respect to the air flow, and the set 11 having the movable refrigerant circuit is moved in parallel to the upstream side of the air flow to thereby form the heat transfer tube downstream and downstream heat exchangers. It is possible to allow air to flow in. According to Japanese Utility Model Laid-Open No. 60-240987, such a staggered arrangement of independent fin groups also has the effect of causing turbulence in the incoming air. The moving refrigerant circuit and the header can be connected by using a flexible pipe with a margin.

The cross fin tube type heat exchanger of the present invention is not limited to the above embodiments, but can be variously modified within the scope of the gist thereof. For example, the type of fin is not limited to the plate fin, and a fin having excellent heat transfer performance can be used.

[0012]

According to the present invention, it is possible to realize a heat exchanger that is resistant to clogging due to frost formation on the air inflow side, and as a result, it is possible to prolong the operating time until defrosting, thus improving the performance of the heat pump. It has a remarkable effect. Further, the present invention is not only effective in clogging with frost, but also effective as a measure against clogging against dust and dirt.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view perpendicular to the tube axis of the heat exchanger according to the first embodiment.

FIG. 3 is a cross-sectional view perpendicular to the tube axis of the heat exchanger of the second embodiment.

FIG. 4 is a detailed view of an outer cylinder and a fin mounting portion of the second embodiment.

FIG. 5 is a perspective view of a third embodiment.

FIG. 6 is a cross-sectional view perpendicular to the tube axis of the heat exchanger of the third embodiment.

[Explanation of symbols]

1 ... Heat transfer tube, 2 ... Fin, 3 ... Fin collar, 4 ... Air flow, 7 ... Damper.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kusumoto 502 Jinritsucho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Manufacturing Co., Ltd. (72) Hiroshi Kogure 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. Tochigi factory

Claims (1)

[Claims] 1. A cross fin tube type heat exchanger arranged in combination in a plurality of rows with respect to an air flow used as an outdoor heat exchanger of a heat pump, wherein a part of the heat exchanger on the most upstream side is movable. A cross fin tube type heat exchanger characterized in that