A CAP OF COLLECTOR PIPE FOR A COLLECTING SUN LIGHT FOR VACUUM LIGHT COLLECTION Technical Field The present invention relates, in general, to vacuum solar collectors each having a solar collecting tube with a mirror provided on an inner surface of the solar collecting tube, and an elliptical metal pipe longitudinally placed at a predetermined position near to a lower portion of the inner surface of the solar collecting tube to allow fluid to flow in the metal pipe and, more particularly, to a cap of a vacuum solar collector, which is provided on each of both ends of the solar collecting tube while the metal pipe is supported in the solar collecting tube by the two caps, so that both side surfaces of the metal pipe are vertically placed in the solar collecting tube, and thus, solar rays collected by the solar collecting tube are efficiently transferred to the metal pipe while maintaining a vacuum in the solar collecting tube, thereby increasing the thermal efficiency of the vacuum solar collector.

Background Art Recently, systems that use green energy are gathering popularity as one way to solve severe problems of energy

exhaustion and atmosphere pollution. A representative system to use the green energy is a system that uses solar energy which is a renewable, clean energy source. The solar energy is used in a variety of industrial fields, for example, solar generations, solar houses, solar rapid water heaters and etc.

The above-mentioned solar house is a system in that the solar energy is used as a heat source. An active solar system is an example of conventional solar systems used in the solar houses. The active solar system stores the solar energy using a mechanical power. That is, water is heated by the solar energy in solar collecting sheets. Thereafter, the heated water is supplied into a thermal energy storage tank by a pump to store the solar energy. The water stored in the thermal energy storage tank is used for space heating and hot water supply. At this time, as a means for collecting the solar energy, the above-mentioned active solar system includes a wide reflecting plate which uses a mirror, and a solar collecting tube which has a circular or semi-circular cross-section, with a metal pipe placed in the solar collecting tube to allow fluid to flow in the metal pipe.

The conventional active solar system has a cap which is coupled to each of both ends of the solar collecting tube having the circular or semi-circular cross-section.

However, the conventional active solar system is

problematic in that the solar collecting tube is not maintained in a vacuum, thus reducing the heat efficiency of the active solar system. Furthermore, the metal pipe is not firmly supported by the caps in the solar collecting tube. Therefore, solar rays collected by the solar collecting tube are not efficiently transferred to the metal tube.

Disclosure of the Invention Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a cap of a vacuum solar collector, which is provided on each of both ends of a solar collecting tube while a metal pipe is supported in the solar collecting tube by two caps, so that both side surfaces of the metal pipe are vertically placed in the solar collecting tube, and thus, solar rays collected by the solar collecting tube are efficiently transferred to the metal pipe while maintaining a vacuum in the solar collecting tube, thereby increasing thermal efficiency of the vacuum solar collector.

Brief Description of the Drawings FIG. 1 is a perspective view of a vacuum solar

collector having caps according to a first embodiment of the present invention; FIG. 2 is an enlarged perspective view of the cap of FIG. 1; FIG. 3 is a sectional view taken along the line A-A of FIG. 1 ; FIG. 4 is a perspective view of a vacuum solar collector having caps according to a second embodiment of the present invention; and FIG. 5 is an enlarged perspective view of the cap of FIG. 4.

Best Mode for Carrying Out the Invention The present invention provides a cap of a vacuum solar collector having a solar collecting tube, with a mirror provided on an inner surface of the solar collecting tube ; an elliptical metal pipe longitudinally placed at a predetermined position near to a lower portion of the inner surface of the solar collecting tube to allow fluid to flow in the metal pipe, with both ends of the metal pipe respectively exposed to outsides of both ends of the solar collecting tube; a cylindrical glass pipe to receive therein the metal pipe ; and a transparent glass sheet to cover an open top of the solar collecting tube while extending outward from the both ends of the solar collecting tube.

The cap is provided on each of the both ends of the vacuum solar collector and includes a main body made of a soft rubber and coupled at an inner surface thereof to each of the both ends of the solar collecting tube while an upper surface of the main body is in close contact with a lower surface of the glass sheet, and a first projection projected inward from the inner surface of the main body and curved downward to have a semi-circular cross-section. The first projection is at an outer surface thereof in close contact with the inner surface of the solar collecting tube. The cap further includes a second projection having a ring-shaped appearance and provided around a radial lower portion of an inner surface of the first projection to be projected inward from the inner surface of the main body. The second projection is at an outer surface thereof in close contact with an inner surface of the cylindrical glass pipe. The cap further includes a third projection provided on a radial lower portion of an inner surface of the second projection to be projected inward from the inner surface of the main body, in a same manner as that of the second projection, with a through hole formed by the third projection to allow each of the both ends of the metal pipe provided in the solar collecting tube to closely pass through the through hole.

As such, the cap for vacuum solar collectors according to the present invention is provided on each of both ends of the solar collecting tube while the metal pipe

is supported in the solar collecting tube by the two caps, so that both side surfaces of the metal pipe are vertically placed in the solar collecting tube. Therefore, solar rays collected by the solar collecting tube are efficiently transferred to the metal pipe while maintaining a vacuum in the solar collecting tube, thus increasing the thermal efficiency of the vacuum solar collector.

Hereinafter, the cap for vacuum solar collectors according to the preferred embodiments of the present invention will be described with reference to the attached drawings.

FIG. 1 is a perspective view of a vacuum solar collector having caps according to a first embodiment of the present invention. FIG. 2 is an enlarged perspective view of the cap of FIG. 1. FIG. 3 is a sectional view taken along the line A-A of FIG. 1.

Referring to FIGS. 1 through 3, the cap 100 for vacuum solar collectors according to the first embodiment of the present invention is provided on each of both ends of a vacuum solar collector 10. The vacuum solar collector 10 has a solar collecting tube 12, with a mirror provided on an inner surface of the solar collecting tube 12. The vacuum solar collector 10 further has an elliptical metal pipe 14 which is longitudinally placed at a predetermined position near to a lower portion of the inner surface of the solar collecting tube 12 to allow fluid to flow in the

metal pipe 14, with both ends of the metal pipe 14 respectively exposed to the outsides of both ends of the solar collecting tube 12. The vacuum solar collector 10 further has a cylindrical glass pipe 16 to receive therein the metal pipe 14, and a transparent glass sheet 18 to cover an open top of the solar collecting tube 12 while extending outward from the both ends of the solar collecting tube 12.

At this time, the cap 100 includes a main body 110 which is made of. a soft rubber, and a first projection 120 which is provided on an inner surface of the main body 110.

The cap 100 further includes a second projection 130 to support thereby the cylindrical glass pipe 16, and a third projection 140 to support thereby the metal pipe 14.

The main body 110 has a plate-shaped appearance. The main body 110 is coupled at the inner surface thereof to each of the both ends of the solar collecting tube 12 while an upper surface of the main body 110 is in close contact with a lower surface of the glass sheet 18 which extends outward from the both ends of the solar collecting tube 12.

The first projection 120, the second projection 130 and the third projection 140 are integrally provided on the inner surface of the main body 110.

The first projection 120 is projected inward from the inner surface of the main body 110 and is curved downward to have a semi-circular cross-section. The first projection

120 is at an outer surface thereof in close contact with the inner surface of the solar collecting tube 12. The second projection 130 has a ring-shaped appearance and is provided around a radial lower portion of an inner surface of the first projection 120 to be projected inward from the inner surface of the main body 110. At this time, an insert gap 132 is defined between the outer surface of the second projection 130 and the inner surface of the first projection 120 to insert the cylindrical glass pipe 16 into the insert gap 132. The second projection 130 is at an outer surface thereof in close contact with an inner surface of the cylindrical glass pipe 16. That is, a radial lower portion of the cylindrical glass pipe 16 is inserted into the insert gap 132. In the meantime, the third projection 140 is provided on a radial lower portion of an inner surface of the second projection 130 to be projected inward from the inner surface of the main body 110, in a same manner as that of the second projection 130. A through hole 142 is formed in the third projection 140 to allow each of the both ends of the metal pipe 14, exposed to the outsides of the both ends of the solar collecting tube 12, to closely pass through the through hole 142.

A process of coupling the two caps 10 having the above-mentioned construction to the vacuum solar collector 10 is as follows.

First, the cylindrical glass pipe 16 having a

predetermined length equal to the solar collecting tube 12 is placed in the solar collecting tube 12 of which the inner surface is vapor-deposited with a predetermined material, such as mercury, tin, aluminum and etc. , to be formed with the mirror. The metal pipe 14, of which radial both side surfaces are compressed, is inserted into the cylindrical glass pipe 16. After both the cylindrical glass pipe 16 and the metal pipe 14 are placed in the solar collecting tube 12 through the above-mentioned process, the cap 100 is coupled to each of the both ends of the solar collecting tube 12. At this time, the outer surface of the first projection 120 of the cap 100 is in close contact with the inner surface of the solar collecting tube 12. The cylindrical glass pipe 16 is inserted into the insert gap 132 of the cap 100 while the inner surface of the cylindrical glass pipe 16 is in close contact with the outer surface of the second projection 130 of the cap 100.

Each of the both ends of the metal pipe 14 passes through the through hole 142 of the third projection 140 of each of the both caps 100, thus being exposed to the outside of each of the both ends of the solar collecting tube 12. At this time, each of the both ends of the metal pipe 14 passes through each of the through holes 142, so that the compressed side surfaces of the metal pipe 14 are vertically placed in the solar collecting tube 12. Thus, the metal pipe 14 efficiently accepts solar rays collected

by the solar collecting tube 12. After the cap 100 is coupled to each of the both ends of the solar collecting tube 12, the glass sheet 18 covers both the solar collecting tube 12 and the caps 100. After both the solar collecting tube 12 and the caps 100 are covered with the glass sheet 18, a bonding agent 150 is applied to each of junctions between the main bodies 110 of the caps 100 and the solar collecting tube 12 and the glass sheet 18.

In the vacuum solar collector 10 with the two caps 100, solar rays are refracted at predetermined angles after being reflected on the mirror which is formed on the inner surface of the solar collecting tube 12 having a semi- circular cross-section. The refracted solar rays are collected to the compressed side surfaces of the metal pipe 14 which is placed at the predetermined position near to the lower portion of the solar collecting pipe 12. As such, the metal pipe 14 must be placed at the predetermined position near to the lower portion of the solar collecting tube 12, because the solar rays, reflected by the mirror formed on the inner surface of the solar collecting tube 12 having a semi-circular, circular or parabolic cross- section, are focused on predetermined positions near to the lower portion of the solar collecting tube 12. Thereafter, heat of the solar rays, collected to the metal pipe 14 through the above-mentioned process, is evenly transferred to the metal pipe 14 through the compressed side surfaces

of the metal pipe 14. Thus, the fluid passing through the metal pipe 14 is heated by the heat of the solar rays. The heated fluid flows into a separate heating equipment which is coupled to the vacuum solar collector 10. In the meantime, the cylindrical glass pipe 16 to receive therein the metal pipe 14 concentrates the solar rays on the metal pipe 14, thus increasing the heat efficiency of the vacuum solar collector of the present invention.

FIG. 4 is a perspective view of a vacuum solar collector having caps according to a second embodiment of the present invention. FIG. 5 is an enlarged perspective view of the cap of FIG. 4.

Referring to FIGS. 4 and 5, the cap 200 for vacuum solar collectors according to the second embodiment of the present invention is provided on each of both ends of a vacuum solar collector 10, in the same manner as that of the first embodiment. The vacuum solar collector 10 has a solar collecting tube 12, with a mirror provided on an inner surface of the solar collecting tube 12. The vacuum solar collector 10 further has an elliptical metal pipe 14 which is longitudinally placed at a predetermined position near to a lower portion of the inner surface of the solar collecting tube 12 to allow fluid to flow in the metal pipe 14, with both ends of the metal pipe 14 respectively exposed to outsides of both ends of the solar collecting tube 12. The vacuum solar collector 10 further has a

transparent glass sheet 18 to cover an open top of the solar collecting tube 12 while extending outward from the both ends of the solar collecting tube 12.

At this time, the cap 200 according to the second embodiment includes a main body 210 which is made of a soft rubber, in the same manner as that of the cap 100 according to the first embodiment. The cap 200 further includes a first projection 220 which is provided on an inner surface of the main body 210 to support the solar collecting tube 12 by the first projection 220. The cap 200 further includes a second projection 230 to support thereby the metal pipe 14.

The main body 210 has a plate-shaped appearance. The main body 210 is coupled at the inner surface thereof to each of the both ends of the solar collecting tube 12 while an upper surface of the main body 210 is in close contact with a lower surface of a glass sheet 18 which extends outward from the both ends of the solar collecting tube 12.

The first projection 220 and the second projection 230 are integrally provided on the inner surface of the main body 210.

The first projection 220 is projected inward from the inner surface of the main body 210 while being curved downward to have a semi-circular cross-section. The first projection 220 is at an outer surface thereof in close contact with the inner surface of the solar collecting tube

12. The second projection 230 is provided on a radial lower portion of an inner surface of the first projection 220 to be projected inward from the inner surface of the main body 210, in a same manner as that of the first projection 220.

A through hole 232 is formed by the second projection 230 to allow each of the both ends of the metal pipe 14, exposed to the outsides of the both ends of the solar collecting tube 12, to closely pass through the through hole 232.

Industrial Applicability As described above, the present invention provides a cap 100 or 200 for vacuum solar collectors, which reduces a gap between a solar collecting tube 12 and a metal pipe 14, so that solar rays collected by the solar collecting tube 12 are efficiently transferred to the metal pipe 14, and which maintains a vacuum in the solar collecting tube 12, thus increasing the heat efficiency of the vacuum solar collector.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.