JPH0328267Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a vacuum double-tube solar collector tube with an improved arrangement of the absorption film surface in a vacuum double-tube solar collector tube with a solar heat absorption film surface. Regarding heat collecting pipes.

[Prior art]

Glass tubes of different diameters with one end closed and the other open are stacked in double layers with a required gap,
Vacuum double-tube solar heat collector tubes, which are mainly composed of vacuum double tubes in which the mutual space between the inner and outer glass tubes is sealed and depressurized, are usually provided with a solar heat absorption membrane surface in order to efficiently collect solar heat. Conventionally, the membrane surface was formed on the surface of the inner glass tube constituting the double vacuum tube.

However, when forming such an absorbing film surface on the surface of a glass tube, the glass tube itself requires careful handling, which reduces the efficiency of forming the film surface and the yield of vacuum double tubes. This increases the cost of tubular solar heat collector tubes.

[Problem that the invention attempts to solve]

The present invention solves the problem of the reduction in the formation efficiency of the film surface and the yield of the vacuum double tube, which existed in the conventional vacuum double tube type solar collector tube in which a solar heat absorbing film surface was formed on the surface of the glass tube. The purpose of this invention is to solve the problem of increased cost of vacuum double-tube type solar heat collection tubes and to improve the efficiency of transmitting solar heat to the heating medium.

[Means for solving problems]

As a means to solve the above-mentioned problems, the vacuum double-tube type solar heat collecting tube according to the present invention has two glass tubes with different diameters, one end of which is closed and the other end of which is open, which are stacked on top of each other. The open ends of the tubes are airtightly joined to each other, and the inner space is depressurized to form a vacuum double tube. The left and right straight pipe portions of the heating medium conduit are inserted in contact with the inner surface, and the left and right straight pipe portions of the heating medium conduit are fitted into a groove formed in the center of a circular arc portion with a substantially semicircular cross section to support surface contact with each other, and the outer periphery of the circular arc portion Two heat conduction bands each having a solar heat absorbing film surface formed on their surfaces are fitted into the inner glass tube facing each other, and further, opposing edges of the two heat conduction bands are placed in contact with each other. A structure is adopted in which a bent portion is formed to elastically bring the surface of the solar heat absorbing film into surface contact with the inner surface of the inner glass tube by biasing the heat conductive band in the direction of separating the heat conductive band.

[Effect]

In the vacuum double-tube type solar heat collecting tube of the present invention, two heat conductive bands fitted inside the inner glass tube are separated from each other through bends formed at both ends. The solar heat absorbing film surface formed on the outer peripheral surface of the heat conduction band is brought into close contact with the inner surface of the inner glass tube, and the heating medium conducting pipe is covered with the heat conduction band. By being supported in contact with the inner glass tube, the solar heat collected by the solar heat absorption film surface that is in elastic surface contact with the inner surface of the inner glass tube is transferred to the heat conduction band formed by the absorption film surface. Directly transmitted to the heating medium conduit.

[Example] Reference numeral 1 denotes a vacuum double tube, including an outer glass tube 2 consisting of a transparent glass straight tube with one end closed and the other end open, and a transparent glass tube 2 with one end closed and the other end open. The inner glass tube 3, which is made of a straight glass tube and has a smaller diameter and length than the outer glass tube 2, is stacked in two layers with a required gap, and their open ends are hermetically joined to form a double layer. The space between the inner and outer glass tubes 2 and 3 is reduced to the required degree of vacuum to prevent the heat absorbed by the inner glass tube 3 from easily propagating to the outer glass tube 2. It is configured as follows.

Reference numeral 4 denotes a U-shaped heating medium conduction tube made of a good thermal conductor such as copper or aluminum, and is accommodated with a straight tube section in line contact with the inner surface of the inner glass tube 3.

The interior of the inner glass tube 3 that accommodates the heating medium conduit 4 has a generally semicircular cross-sectional shape.
The heating medium has a length slightly shorter than the inner glass tube 3, and has support grooves 5 and 6 in the center that are in uniform surface contact with the straight pipe part of the heating medium conduit 4 and cover the straight pipe part. Thermal conduction bands 7 and 8 made of thin metal plates that are good conductors and have high bending elasticity are housed in surface contact with the inner surface of the inner glass tube 3.

A heat conduction band 7 housed on the inner surface of the inner glass tube 3
Both ends in the width direction (circumferential direction) of and 8 have relief portions 9 and 10 that are bent inwardly from the inner surface of the inner glass tube 3 and can be elastically deformed. The contact parts 11 and 12, which bias the arc portion of the heat conduction band 7 in the direction of contacting the inner surface of the inner glass tube 3, are moved into contact with each other by the elastic forces 9 and 10. It is formed to extend ahead of parts 9 and 10. Here, according to this embodiment, the escape parts 9 and 10 are formed of slopes, and the contact parts 11 and 12 are formed of plane surfaces, but in this case, the relief parts 9 and 10 are mutually The contact parts 11 and 12 in contact with the heat conduction band 7
and 8, the arc portions of the heat conduction bands 7 and 8 are evenly distributed in each part of the inner glass tube 3.
The predetermined length and angle θ (for example, 120°≦θ≦150°) are set to bring the surface into surface contact with the inner surface of the substrate.

The heat-conducting bands 7 and 8 have a solar heat absorbing film surface 13 formed on their outer peripheral portions that come into contact with the inner glass tube 3. The solar heat absorption film surface 13 has excellent heat absorption properties and also has the function of suppressing the radiation of the absorbed heat. For example, if it is formed with a composite film of two layers, an inner layer and an outer layer, the inner layer is a heat absorption layer. metal oxide or composite metal carbide film with
The outer layer can be a metal film with low thermal emittance that reflects heat radiated from the inner layer toward the inner layer. Therefore, the arc portion of the heat conduction band 7 is
In a state where the surface of the solar heat absorbing film surface 13 is elastically brought into contact with the inner surface of the inner glass tube 3 due to the elastic force between the relief portions 9 and 10 and the contact portions 11 and 12, the solar heat absorption film surface 13 is It is closely attached to the inner surface of the inner glass tube 3, and the heating medium conduit tube 4 is closely attached to the heat conductive band 7 so as to be covered therewith. Note that the solar heat absorbing film surface may be provided on the entire outer circumferential surface of the heat conduction band depending on the material.

[Effect of idea]

The vacuum double tube type solar heat collecting tube of the present invention forms the solar heat absorption film surface into an arc-shaped heat conduction band that is much easier to handle than the vacuum double tube, so it improves the formation efficiency of the film surface and It is possible to prevent a decrease in the yield of vacuum double tubes, and as a result, it is possible to achieve a cost reduction of vacuum double tube type solar heat collecting tubes.

Furthermore, since the solar heat absorption film surface is directly formed on the heat conduction band that the heating medium conduit comes into contact with, the heat collected and stored by the action of the absorption film surface can be directly and efficiently absorbed. It can be transmitted to the heating medium conduit.

In addition, the heat conduction band is composed of two approximately semicircular pieces, each of which individually supports the straight pipe portion of the heating medium conduit in surface contact, and the ends of the heat conduction band in the width direction Since the escape part and the contact part are provided as bent parts to bring them into elastic contact with each other, the contact force or expansion force of the heat conduction band to the inner surface of the inner glass tube is equalized in each part. The heat conduction band maintains surface contact with the inner surface of the inner glass tube almost uniformly and extremely strongly, and elastically adheres to the inner surface of the inner glass tube and the heating medium conducting tube,
As a result, the convection space or heat transfer space for the heat absorbed from the inner glass tube into the heat conduction band and the heat transferred from the heat conduction band to the heating medium conduit tube is narrowed. It is possible to achieve a heat collection effect as well as an efficient heat transfer effect to the heating medium conduction tube by the heat conduction band.

[Brief explanation of the drawing]

The drawings show one embodiment of the vacuum double tube type solar heat collecting tube according to the present invention, and FIG. 1 is a vertical side view;
FIG. 2 is a cross-sectional view. 1...Double vacuum tube, 2...Outer glass tube, 3...
...Inner glass tube, 4...Heating medium conduit tube, 5 and 6...Support groove, 7 and 8...Heat conduction band, 9 and 1
0... Relief part, 11 and 12... Contact part, 13...
...Solar heat absorption film surface.

Claims (1)

[Claims for Utility Model Registration] Glass tubes 2 and 3 of different diameters, one end of which is closed and the other end of which is open, are overlapped in double layers with a required gap, and the open ends of the inner and outer glass tubes 2 and 3 are It is equipped with a vacuum double tube which is airtightly joined to each other and whose internal space is depressurized, and the straight pipe portion of the heating medium conduction pipe 4 which is bent into a U shape is brought into contact with the inner surface of the inner glass tube 3. The left and right straight pipe portions of the heating medium conduit tube 4 are inserted into a single groove 5, 6 formed at the center of an arcuate portion having a substantially semicircular cross section.
Two heat conductive bands 7 and 8, each having a solar heat absorbing film surface 13 formed on the outer circumferential surface of the circular arc portion thereof, are fitted into the inner glass tube 3 facing each other and supported in surface contact with each other. Furthermore, the opposing edges of the two heat conduction bands 7 and 8 are urged in a direction that abuts each other and separates the heat conduction bands, so that the solar heat absorption film surface 13 is attached to the inner glass tube 3. a bending portion 9 that elastically makes surface contact with the inner surface of the
10, 11, and 12 are vacuum double tube type solar heat collecting tubes.