Flat solar collector

A flat solar collector arrangement used for collecting solar energy in which a metal tub serving as a carrier and made by a deep-drawn process, is filled with synthetic material. A heat carrier channel system and a collector plate are located on top of the synthetic material. A protective disk is connected by a rubber gasket ring to an edge of the metal tub, and a bellows-shaped device in the metal tub between the collector plate and the protective disk is used for influencing the enclosed volume. The metal tub may be made of galvanized sheet iron, and the upper rim of the metal tub is drawn outward, parallel to the bottom of the tub. The synthetic material, furthermore, may be in the form of a flaky styropor mass which serves as heat insulating material. The channel system and the collector plate are integrated as a single one-plate system. The metal tub, furthermore, has at least one opening which is closed by means of the bellows-shaped device, and is directed inward or outward.

BACKGROUND OF THE INVENTION 
The present invention relates to a flat collector to collect solar energy, 
with a carrier which holds a collector plate, a heat carrier channel 
system and a protective disk (pane). 
Flat collectors are used to collect solar energy and for storage in a heat 
carrier medium, ordinarily water. The temperatures reached there are 
adequate for home heating and pool heating, or for providing hot water. 
With the continued consumption of energy reserves, such as crude oil, the 
use of solar energy collectors has become more urgent; the various 
technologies attempt to develop rational arrangements for large-scale use. 
The general aim is to porduce collectors of long life and reliability and 
minimum purchase price, and minimum assembly, operating and maintenance 
costs. Presently known collectors meet only some of these requirements, 
but not all of them. 
Presently known collectors with metal carriers are difficult to manufacture 
and final assembly is difficult. They essentially consist of a metal 
housing open on top and lined with heat-insulating material. This housing 
encloses the channel system, the collector plate and a protective disk and 
they are fastened by crimping the housing walls or screw-fastened metal or 
plastic strips. The lining with thermal insulator and the crimping or 
screw-fastening are time-consuming steps in manufacture. 
There are also known collectors with a carrier housing of synthetic 
material which have a relatively short life and high material costs. 
It is the object of the present invention to provide a flat collector of 
the foregoing species which can be produced by moderately-priced mass 
production methods and nevertheless has a long life and reliability. 
ANOTHER OBJECT OF THE PRESENT INVENTION IS TO PROVIDE A SOLAR COLLECTOR OF 
THE FOREGOING CHARACTER WHICH IS SUBSTANTIALLY SIMPLE IN CONSTRUCTION AND 
MAY BE ECONOMICALLY FABRICATED. 
A further object of the present invention is to provide a solar collector 
arrangement, as described, which may be easily maintained in service. 
SUMMARY OF THE INVENTION 
The objects of the present invention are achieved by providing a metal tub 
produced by the deep-draw method filled with synthetic material. On top of 
the synthetic material, the channel system and the collector plate are 
placed. The cover disk is connected by a rubber gasket with the edge of 
the metal tub, and the tub has a bellow-like device between the collector 
plate and the cover disk; this device determines the volume enclosed. 
This design can be produced by simple manufacturing steps, with the time 
interval of the individual steps being very small. The metal tub which may 
be of galvanized sheet iron, has a much longer life and cheaper material 
cost than the plastic designs. The use of synthetic material, e.g., 
styropor flakes or glass wool, requires no manufacturing steps, such as 
fastening, pasting. 
When the upper rim of the metal tub is simultaneously drawn by the 
deep-draw method toward the outside and parallel to the bottom of the tub, 
the cover plate can be clamped to the tub via a rubber gasket ring, the 
same way as windows are fastened to motor vehicles, with the remaining gap 
between the cover disk and collector plate being sealed sufficiently. The 
good seal is necessary to prevent entry of moist air and possible 
condensation of the air humidity on the disk and on the plate. 
Heavy temperature change loads or air expansion change within the closed 
gap endangers the reliability of collectors through possible pressure 
damage. To prevent this, the invention provides bellow-like means which 
may be arranged on the wall or in the bottom of the metal tub and which 
cause a volume compensation in the gap during changing temperatures. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of specific embodiments when read in 
connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The collector 10 shown in a vertical cross section comprises a metal tub 11 
whose upper edge 12 is bent outward. The tub is filled up to a certain 
level with heat-insulating flake-like styropor or glass wool 13. This 
insulating layer carries a plate system 14 which has channels 17 between 
two partially connected plates 15 and 16. The upper plate 16 
simultaneously constitutes the collector plate mounting an absorption 
layer. On the outer rim 12 of the tub there is a protective disk 18 
fastened by means of a rubber gasket 19. 
Between the plate system 14 and the protective disk 18 there remains an 
intermediate space 20 whose volume can be varied by means of a bellows 21 
in accordance with the temperature fluctuations to which the collectors 
are usually exposed to balance the pressures. This bellows 21 which may be 
directed inward or outward is fastened to a perforation 22 of the tub 11 
with a seal. 
The line connections for the channel system 17, not shown, can be passed 
through the tub in the usual manner and connected to the channel system 
17. By means of rubber flaps 23 which are an integral part of rubber ring 
19, besides fastening the protective disk, the plate system 14 can be 
pressed against the styropor layer 13 so that no fastening with screws, or 
similiar devices, is necessary. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention, and 
therefore, such adaptations should and are intended to be comprehended 
within the meaning and range of equivalents of the following claims.