JPS5924338B2 - solar collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a solar collector (
(hereinafter referred to as collector).

In order to improve heat collection efficiency, recent collectors have been proposed in which a heat receiving section is incorporated inside a vacuum container.

Therefore, in order to further improve the heat collection efficiency, a reflecting mirror is provided below the collector at a position away from the collector, or a vacuum container (usually a glass tube) is used instead of the reflecting mirror. A collector with a high reflectivity metal thin film such as aluminum formed on the lower part of the inner surface has been proposed, but the present invention belongs to the latter, and provides a collector with a metal film that can minimize the heat radiated from the end of the glass tube. It is something to do.

Another object of the present invention is to provide a method for depositing a thin metal film on the lower inner surface of a transparent container easily and with accurate dimensions.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a longitudinal sectional view of the collector when the heat receiving part 2 is inserted into the glass tube 1 which has not yet been evacuated.

A thin aluminum film 3 is deposited on the inner surface of the glass tube 1, as shown by diagonal lines.

fx 4 in the diagram is the exhaust pipe. This aluminum thin film 3
As is clear from FIGS. 1 and 2, at the middle part of the glass tube 1 and at the other end where the exhaust pipe 4 is not provided, that is, at the right end (this is not shown), the lower part of the glass tube 1 has a half circumference. As is clear from FIGS. 1 and 3, at the end where the exhaust pipe 4 is located.

It is formed (deposited) all around the circumference.

The heat receiving part 2 is composed of a cylindrical heat collecting plate 5 and a single-shaped heat collecting vibro. It is fixed inside by welding etc.

Since the surface of the heat collecting plate 5 is normally coated with a selective absorption film, there is almost no heat radiation outward from it, but since there is no selective absorption film on the surface of the heat collection vibro, the above Heat radiation from the protrusion T is always present.

Further, since the inner surface of the heat collecting plate 5 is not coated with a selective absorption film, heat is also radiated from the opening at the end thereof.

However, the aluminum thin film 3 deposited in the above shape not only reflects solar heat to the heat receiving part 2;
At the end of the glass tube 1, the heat that is intended to be radiated to the outside is reflected from the protrusion 7 of the heat collecting vibro and the end of the heat collecting body 5, thereby confining it inside. This will improve the heat collection efficiency.

In short, the thin film 3 is attached from both ends of the heat collector 5 to the entire circumference of the inner surface of the transparent container corresponding to the outer A rule, and is attached only to the lower half of the inner surface of the transparent container corresponding to the heat collector 5. That's why.

Incidentally, the glass tube 1 is finally degassed through the exhaust pipe 4 to be in a vacuum state.

Next, a method of vapor depositing aluminum in the above shape on the inner surface of the glass tube will be explained.

In FIG. 4, the interior 8 of the glass tube 1 is evacuated, and a tungsten wire 9 with aluminum fused to its surface is suspended along the tube axis, and is further attached to the inner surface of the glass tube. is a thin magnetic plate 10 (for example, iron,
A plurality of semicircular magnets 11 are fixed to the outside of the glass tube in correspondence with the magnetic plate 10.

Therefore, the magnetic plate 10 can be accurately fixed at a predetermined position within the glass tube by the magnetic force of the magnet 11.

However, when aluminum is deposited in this state, the magnetic plate 10 serves as a deposition mask, and the aluminum thin film 3 having a predetermined shape as shown in FIG. 1 is accurately deposited on the inner surface of the glass tube.

After vapor deposition, the external magnet 11 is removed and the magnetic plate 1
Just remove 0.

Note that the magnetic plate 10I/i may have a gutter-like shape in advance to match the inner diameter of the glass tube, but even if it is a short fence-like thin plate, the inner surface of the glass tube 1 may be formed by external magnetic force. A similar step 11 can be performed by bending along the arc in a circular arc shape.

As described above, a metal reflective film can be deposited on the inner surface of a glass tube very easily and accurately.

Moreover, the metal reflective film 3 thus obtained can be deposited over the entire circumference at the end of the glass tube.

As mentioned above, according to the collector of the present invention, it is possible to effectively prevent heat radiation from the end of the heat receiving portion, and therefore the heat collecting efficiency of the collector itself can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the main part of the collector of the present invention, and FIG.
FIG. 3 is a sectional view taken along line AA in the figure, FIG. 3 is a sectional view taken along line BB in FIG. Code: 1...Glass tube, 2...Heat receiving part, 3...Reflecting part.

Claims (1)

[Scope of Claims] 1. A heat receiving part including a heat collector is disposed inside a bottomed cylindrical transparent container, and a reflecting part is formed on the inner surface of the transparent container to reflect sunlight to the heat collector. In the solar heat collector, the reflecting portion has a portion corresponding to the heat collector formed over half the circumference of the transparent container, and a portion corresponding to the outer side from the end of the heat collector formed over the entire circumference of the transparent container. A solar collector characterized by: 2. The solar heat collector according to claim 1, wherein the reflective portion is a metal vapor-deposited film.