JPH0128303B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar heat collector used in a solar heat utilization system.

Conventionally, this type of solar heat collection device has a glass tube whose both ends are closed with metal end caps, and a heat collection pipe with a heat collection plate is placed hermetically through the glass container. is evacuated to create a high vacuum. This device uses a heat collection plate to absorb mainly infrared rays from sunlight and conducts this heat to a heat medium flowing in a heat collection pipe to heat this heat medium. For example, when the heat medium is water, 80
It has excellent heat collecting performance, being able to heat up to ~90℃. From this, indoor heating,
It has the advantage of not only supplying hot water for baths and kitchens, but also cooling when combined with an absorption refrigerator. In addition, since such equipment creates a vacuum inside the glass container, it is necessary to connect the end of the glass tube and the end cap in an airtight manner. Conventionally, these connections have been configured as follows. It's summery. That is, the glass tube and the end cap are joined by forming a concave fitting groove in the peripheral edge of the end cap, and the end of the glass tube is fitted into the fitting groove. Glass bonding is performed by filling the gap between the fitting grooves with granular bonding glass, and then heating the vicinity of the fitting groove with a burner or the like to melt the bonding glass. However, in such glass bonding, when the granular bonded glass filled in the fitting groove is melted, the air between the bonded glasses cannot be completely removed from the bonded portion. As a result, air bubbles are generated within the joint, and these air bubbles may prevent the glass tube and the end cap from being airtightly joined. Furthermore, due to the difference in thermal expansion between the glass tube and the end cap, the end cap is deformed in the direction in which the diameter of its fitting groove increases; however, the end of the glass tube is fitted into this fitting groove. Because of this, the tensile force due to the above deformation acts on this joint, causing a large strain in this joint. That is, this is because glass has a property of being strong against compressive force but weak against tensile force.

Therefore, there is a problem in that the joint portion is easily damaged by changes in temperature or slight mechanical shock. In addition, since rainwater, etc. tends to accumulate in the above-mentioned fitting groove, if the joint parts are corroded and damaged by this rainwater, or if this rainwater, etc. freezes, the joint parts may become damaged due to the freezing. There is a problem with the product being damaged. Furthermore, when the joint is severely damaged, the inside of the glass tube is in a high vacuum, so there is a problem that the glass tube itself may be damaged.

This invention was made based on these circumstances, and its purpose is to form the end cap diameter to be smaller than the end diameter of the glass tube, and to glass-bond them, thereby forming a bonded part. It is an object of the present invention to provide a solar heat collecting device that can improve the airtightness of the glass tube and strengthen the joint to prevent damage to the joint and damage to the glass tube itself caused by the damage.

An example of this invention is shown below in Figures 1 to 3.
This will be explained based on the diagram.

In the figure, 1 is a glass tube made of borosilicate glass, for example. End caps 2a and 2b are disposed at both ends of the glass tube 1, and these end caps 2a and 2b hermetically close both ends of the glass tube 1. That is, these end caps 2a and 2b are formed by bending the peripheral edge of a metal disk, and the end cap diameter of the bent portion 3 is configured to be smaller than the diameter of the glass tube end of the glass tube 1. has been done. The end caps 2a, 2b and the glass tube 1 are joined to each other as shown in FIG.
Glass tube 1 at the tip of bent part 3, 3 of a, 2b
Beat-wrap bonded glass 4, 4 made of the same material as
After fitting these bent portions 3, 3 into the glass tube 1 so that the bonded glass 4, 4 overlaps the inner circumferential surface of the glass tube 1, these bonded portions are heated with a burner or the like to form the glass tube 1. The end caps 2a, 2b are bonded by melting the ends of the glass 4, 4, and the end caps 2a, 2b are bonded together.
and the glass tube 1 are hermetically joined.

A heat collecting pipe 5 is passed through the glass tube 1 at a position substantially on the tube axis. The heat collecting pipe 5 constitutes a passage for a heat medium, and is made of a copper pipe or the like having excellent thermal conductivity. The heat collecting pipe 5 passes through the end caps 2a and 2b in an airtight manner, and is airtightly connected to one end cap 2a via a telescopic pipe 6, as shown in FIG. ing. The expandable pipe 6 has a concentric double pipe structure so as to constitute the heat collecting pipe 5 and the exhaust space 7, and one end is hermetically joined to the end cap 2a, and the other end is connected to the heat collecting pipe 5. Airtightly joined to the outer circumferential surface.
Note that the above-mentioned joining is performed by silver brazing or the like. Also,
The telescopic pipe 6 is composed of a bellows 8, for example,
Thermal expansion and contraction of the heat collecting pipe 5 can be absorbed by the bellows 8. Note that 9 is an exhaust pipe connected to the telescopic pipe 5, and this exhaust pipe 9 is connected to a vacuum pump when evacuating the inside of the glass tube 1, and is sealed when a predetermined evacuation is completed. .

A heat collecting plate 10 is housed inside the glass tube 1. The heat collecting plate 10 is formed of a plate with excellent thermal conductivity such as aluminum,
It is closely joined to the outer surface of the heat collecting pipe 5 at its center. Note that the heat collecting pipe 5 and the heat collecting plate 10 are joined by caulking, silver brazing, or the like. The heat collecting plate 10 has a surface facing the sun, and a selective absorption film (not shown) is provided on this surface.
has been formed. This selective absorption film satisfactorily absorbs the wavelength range of sunlight and prevents the emission of infrared wavelengths. When the heat collecting plate 10 is irradiated with sunlight, this selective absorption film collects more heat. The temperature of the plate 10 increases. The heat of the heat collecting plate 10 is conducted to the heat collecting pipe 5 and heats the heat medium flowing into the heat collecting pipe 5.
Moreover, since the inside of the glass tube 1 is maintained at a high degree of vacuum, the radiation of solar heat absorbed by the heat collecting plate 10 is prevented, and this solar heat is effectively conducted to the heat collecting pipe 5, thereby increasing the heat collection efficiency. It has become something that has been enhanced. Note that 11 is a support for holding the heat collecting plate 10 on the tube axis of the glass tube 1.

According to one embodiment with the above configuration, the end caps 2a, 2b and the glass tube 1 are bonded by beat winding the bonding glasses 4, 4 around the bent portions 3, 3 of the end caps 2a, 2b in advance. Since the bonding is done by melting both ends of the glasses 4, 4 and the glass tube 1, no air bubbles are generated in the bond between the end caps 2a, 2b and the glass tube 1. Therefore, this joint can be ensured to be airtight. Moreover, the above-mentioned joining is performed by the end caps 2a,
This is done by joining the bent portions 3, 3 of the glass tube 1 to the end portion of the glass tube 1, and the end cap diameter of the bent portion 3 is configured to be smaller than the diameter of the glass tube end portion of the glass tube 1. Therefore, even if the bent portions 3, 3 expand in diameter due to the difference in thermal expansion between the end caps 3, 3 and the glass tube 1, or try to deform in the direction of peeling,
Since this deformation acts as a compressive force on the joint between the end caps 3, 3 and the glass tube 1, it is possible to reduce the strain that occurs at this joint, and this joint can withstand changes in temperature and mechanical shock. The department can be strengthened. In addition, since the above-mentioned joint does not have a recess where rainwater or the like can accumulate, there is no risk that the joint will be corroded and damaged by this rainwater, or that this joint will be damaged by freezing of this rainwater. Nor. Therefore, by strengthening the joint to prevent damage, it is also possible to prevent damage to the glass tube 1 itself, whose interior is under high vacuum.

Further, according to such an embodiment, there is no need to form a fitting groove in which the end of the glass tube 1 is fitted in the peripheral edge of the end caps 2a, 2b, so that the shape of the end caps 2a, 2b can be changed. Since the diameter of the bent portions 3, 3 of the end caps 2a, 2b is made smaller than the diameter of the end of the glass tube 1, these end caps 2a,
Glass bonding between the glass tube 2b and the glass tube 1 becomes easy, and the manufacturing of the device becomes simple. Furthermore, when installing this device, the mounting band is attached to the glass tube 1, but the diameter of the bent portions 3, 3 of the end caps 2a, 2b is smaller than the diameter of the end of the glass tube 1. Therefore, there is an advantage that the mounting band can be easily fitted into the glass tube 1 during mounting.

As explained above, in the present invention, the diameter of the end cap that airtightly closes the end of the glass tube is formed to be smaller than the diameter of the end of the glass tube, and the end cap and the glass tube are connected to each other. It is characterized by glass bonding. Therefore, when bonding these end caps and the glass tube, it is possible to use bonded glass that has been bead wrapped around the end caps in advance, so that air bubbles will not form within these joints. , the airtightness of this joint can be ensured. Also, since the diameter of the end cap is smaller than the end diameter of the glass tube,
Deformation of the end cap due to the differential thermal expansion between the end cap and the glass tube acts as a compressive force on the joint. Therefore, the strain that occurs in this joint can be reduced, which has great effects, such as making the joint stronger and preventing damage to the joint and the glass tube itself caused by this damage. .

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention, Figure 1 is a perspective view of the device, Figure 2 is a sectional view in Figure 1, and Figure 3 shows the main parts before glass bonding. FIG. DESCRIPTION OF SYMBOLS 1... Glass tube, 2a, 2b... End cap, 5... Heat collection pipe, 10... Heat collection plate.

Claims (1)

[Scope of Claims] 1. A glass tube, an end cap that airtightly closes an end of the glass tube, and a heating medium passage that is disposed in the glass tube by airtightly penetrating the end cap. A heat collection pipe, and a heat collection device that is arranged in the glass tube in connection with the heat collection pipe, and heats the heat medium by conducting the solar heat obtained from sunlight to the heat medium flowing inside the heat collection pipe. In a solar heat collector equipped with a plate, the joint portion between the glass tube and the end cap is formed so that the outer diameter of the end cap is smaller than the inner diameter of the glass tube, and the outer surface of the end cap and the inner surface of the glass tube are connected to each other. A solar heat collector characterized in that the space is bonded with bonded glass.