Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Patent
1994-12-27
1996-03-05
Walberg, Teresa J.
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
219385, 373 73, 373 77, 432206, F27B 904, F27B 932, F27D 118
Patent
active
054969883
DESCRIPTION:
BRIEF SUMMARY
STATE OF THE ART
The invention relates to a device for soldering components on plates under the effect of a gas, and having an at least two-piece housing, and with a seal being provided between the housing elements. As a rule such devices, hereinafter called continuous furnace, have a conduit on whose exterior or interior sides heating devices are disposed. To execute the soldering process in a defined atmosphere, a protective gas is preferably blown into the center area of the conduit, which, when flowing out in the direction of the conduit openings, displaces the oxygen flowing or diffusing in.
The furnace of this type conduit of protective gas continuous furnaces must be accessible for maintenance and cleaning work. Thus the furnace conduit, which inevitably must be divisible, must be absolutely gas-tight during operation, except for the inlet and outlet openings. Because of the large drop in partial oxygen pressure, even the smallest microscopic fissures in the furnace wall result in considerable enrichment of the protective gas atmosphere with oxygen and thus in a decrease in the quality of the product. The points of separation of the divisible conduit are particularly susceptible to such micro-leaks. Known continuous furnaces have flanges which are screwed or clamped together with inserted seals of copper or heat-resistant plastic. These connecting points are subject to great mechanical loads because of the stresses during changes in temperature when the furnaces are switched on and off, as well as the operationally caused temperature gradients in the linear (longitudinal) direction of the furnace.
SUMMARY AND ADVANTAGES OF THE INVENTION
The disadvantages of the prior art devices are overcome according to the present invention by a device for soldering components on plates under the effect of a gas which has an at least two-piece housing with a seal being provided between the housing elements, and wherein a liquid is utilized as the sealing means.
In contrast to the known devices, the device in accordance with the invention basically described above has the advantage that temperature-caused linear changes of individual parts of the continuous furnace do not result in any stresses within the sealing means and that leaky places cannot occur. Furthermore, the furnace chamber is easily accessible at any time, because of which it is not necessary to install a fresh, expensive, specially adapted seal after one or a defined number of openings. The liquid sealant is furthermore considerably cheaper and simpler and can be replaced more quickly than conventional solid seals.
Mutual sealing of the two housing elements by means of a liquid makes possible the assured gas tightness while making the least demands on precise manufacture.
Advantageous embodiments of the device in accordance with the main claim are possible by means of the steps recited in the dependent claims. A simple and uncomplicated structure results if a first housing element has at least one liquid reservoir into which a second, preferably cover-shaped housing element partially dips. The cover-shaped housing element is then placed into the still liquid from above. Additional clamping of the two housing elements in respect to each other is not required, the weight of the resting upper housing element is sufficient for this.
A solid structure, which through thermal expansion only causes small mechanical forces, can be achieved if the housing elements have solid, bearing components as well as thin-walled elements which are exposed to the heat generation and surround the actual furnace chamber.
It is furthermore advantageous if the means supporting the conveying device and/or heating device are only fixedly connected on one side with the respective housing element and with another side rest loosely on the housing element. Heat expansion without causing twisting can take place by means of this.
DRAWINGS
The principle of the device is illustrated in the sole drawing FIGURE and will be explained in detail in the subsequent description while rec
REFERENCES:
patent: 2081990 (1937-06-01), Eberwein
patent: 2283982 (1942-05-01), Germany
patent: 2558088 (1951-06-01), Hoop
patent: 3975145 (1976-08-01), Hill et al.
patent: 4833301 (1989-05-01), Furtek
patent: 5296680 (1994-03-01), Yamada
patent: 5317127 (1994-05-01), Brewster et al.
Pelham J.
Robert & Bosch GmbH
Walberg Teresa J.
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