Apparatus for cooling hot gas

In a heat exchanger, a thin tube plate is reinforced by means of a heavy support plate spaced therefrom. The tubes are fixed to the tube plate and pass through enlarged openings in the support plate but are anchored to the support plate by anchoring devices which allow the liquid to be heated to pass from the chamber provided between the two plates through the annular passages between the tubes and the enlarged openings of the support plate.

The invention relates to an apparatus for cooling hot gas which comprises a 
vessel having a nest of tubes, the hot gas flowing through the tubes and 
cooling water or the like flowing round the tubes and the tubes being 
mounted at one end in a tube plate which closes a hot gas supply chamber. 
When the hot gas to be cooled has a very high temperature, the hot gas 
supply chamber must be provided with an insulating layer and as a result, 
the insulated portion of the inner surface of said chamber assumes almost 
the same temperature as the gas. If this temperature lies between 
1000.degree. and 1500.degree. C., the tube plate is subjected to very high 
thermal stresses. This means that the tube plate cannot have a thickness 
greater than 20 to 25 mm. If the liquid chamber is used for generating 
steam, for example, and high pressures can thus occur, said tube plate is 
not able to withstand such pressures. This is true in particular when 
helically wound tubes are used because such tubes cannot transmit forces. 
The purpose of the invention is to provide an apparatus for cooling hot 
gas in which a high gas temperature can occur with no detrimental effect 
and a high pressure is also admissible in the liquid chamber. 
According to the invention, the tube plate is of light construction, a 
heavy support plate is disposed directly behind said tube plate and 
supported by the vessel wall, the tubes project through openings in the 
support plate, the tubes rest on the side remote from the tube plate on 
the support plate via rings secured on the tube which have passage 
openings for the cooling water or the like which adjoin continuous gaps 
disposed round the tubes, and the space between the tube plate and the 
support plate lying therebehind is provided with a supply for the cooling 
water or the like. In such a construction, the tube plate is supported by 
the heavy support plate. Due to the gap between the tubes and the wall of 
the openings in the support plate the tubes are effectively cooled over 
the entire length. The cooling water or the like flows in constrained 
manner round the tubes. The tube plate is also effectively cooled on the 
rear side because the cooling water or the like flows along said side. 
In a convenient further development of the invention the supply means for 
the cooling water or the like is formed by a tube which is led through an 
opening in the support plate and sealingly secured in the latter and the 
end of which is secured to the tube plate to provide an additional 
supporting effect, said tube comprising openings in the portion lying 
between the tube plate and the support plate. The cooling water or the 
like is thus supplied centrally. If the gaps between the tube and the 
support plate are not made too wide, a pressure drop occurs across said 
gaps so that the cooling liquid is distributed uniformly over said gaps 
and over the tube plate. 
Furthermore, according to the invention, the supply tube for the cooling 
water or the like is connected to the support plate only on the side of 
said plate remote from the tube plate and between the portion of the tubes 
projecting through the support plate and the wall of the opening an 
encircling gap open at one end is present. In such a construction gap, 
corrosion is avoided between the vessel wall and the supply tube. 
According to the invention, the tube plate is bent at the edges and welded 
with the edge to the support plate. An additional flange connection for 
mounting the tube plate is then not necessary. 
Finally, according to the invention the rings round the tubes may be 
fixedly welded and supported by rings fixedly welded thereto or integral 
therewith with passage openings in central manner in appropriate recessed 
areas of the support plate disposed round the tubes. Due to the recessed 
areas, it is ensured that the gap round the tube is of uniform width 
throughout. This is important for proper uniform cooling of the tubes in 
the support plate.

DETAILED DESCRIPTION OF THE INVENTION 
The apparatus comprises a vessel 1 in which the helical convolutions of 
tubes 2 are accommodated. The vessel has a discharge 3 for cooling water 
or the like. The tubes 2 adjoin a plurality of collecting boxes 4 which 
are connected to a discharge 5 for the gas. The tubes 2 project through 
openings 6 in a heavy support plate 7. The ends of the tubes are secured 
in a tube plate 8 which is bent at the edges and welded at 9 with the 
edges to the support plate 7. The support plate 7 is welded to the vessel 
1. Furthermore, the support plate rests on a vessel 10 which forms a 
chamber 11 for the hot gas. The chamber 11 has a supply tube 12 for said 
hot gas. The vessel 10 is lined on the inside with an insulating layer 13. 
The latter protects the wall of the vessel 10 which is to withstand the 
high gas pressure. 
Cooling liquid can be supplied to the chamber 14 between the tube plate 8 
and the support plate 7 via a tube 15. The tube 15 projects through an 
opening 16 in the plate 7. Between the wall of the opening 16 and the tube 
15, there is a wide gap 17. Near the upper edge of the support plate, the 
tube 15 is welded to said plate 7. Furthermore, the tube 15 is welded at 
the end at 18 to the tube plate 8. The tube has openings 19 which open 
into the space 14. Welded to the tubes 2 is a ring 20. A tubular ring 21 
with openings 23 is fixedly welded to the ring 20 and supported in a 
matching recess 22 in the plate 7 so that the ring 21 and the tube 2 are 
centered with respect to the opening 16. 
Hot gas is supplied through the tubes 12 and can flow via tubes 2 to the 
discharge 5. When the gas has a very high temperature, for example up to 
1500.degree. C., the inner wall of the insulation 13 will assume the same 
temperature. Because of the direct contact with the gas and the radiation 
the tube plate 8 also assumes a high temperature on the side of the 
chamber 11. On the other side the plate is cooled by cooling water from 
the conduit 15. The plate should not be too thick since otherwise the 
thermal stresses will be too high. When the vessel 1 has an inner 
pressure, the pressure forces exerted on the thin tube plate 8 are 
transmitted to the tubes 2 and the rings 20 and 21 to the plate 7. This 
support plate thus provides the necessary resistance. When the very hot 
gases flow through the tubes and cooling water is introduced into the 
chamber 14 via the conduit 15, the tube is cooled uniformly all over due 
to the gaps 6 round the tubes 2. In spite of the connection to the plates 
7 for supporting the tube plate 8 no overheating of the tubes occurs. 
Because of the wide gap 17 no gap corrosion occurs between the wall of the 
hole 16 and the wall of the conduit 15. The number of tubes which can be 
disposed in the tube plate is not limited because due to the supporting of 
the tubes the thickness of the plate 7 is independent of the diameter 
thereof.