Improvements in or relating to Steam Heating Apparatus and to Condensing or Cooling Apparatus.
Year: 1899

page_text: Date of Application, 13th June, 1899
Complete Specification Left, 10th Jan., 1900-Accepted, 10th Feb., 1900
Improvements in or relating to Steam Heating Apparatus and to
Condensing or Cooling Apparatus.
I, RODOLPHE RAU, of 7, Rue Kuhn, Schiltigheim-Strassburg, Germany,
Engineer, do hereby declare the nature of this invention to be as follows:-
In steam-heating apparatus ribbed tubes are often used that are made entirely
of cast iron. These ribbed tubes possess the advantage, over smooth drawn
tubes, of having a considerably greater heating surface for the same length;;
they have, however, the disadvantage that they offer but little resistance to
external blows or to internal water blows caused by the condensation of the
steam. In more recent apparatus, for the sake of safety, cast-iron ribbed tubes
are employed only in connexion with low pressure heating apparatus with ex-
panded steam, and wrought iron tubes with ribs pushed over or cast on, for high
pressure heating-apparatus.
In the case of wrought iron tubes with pushed-over ribs, it is constructively.
hardly possible to fix the rib-elements so closely on the wall of the tubes as
to secure a direct contact between the two bodies, and, since there is undoubtedly
a layer of air between the pushed-on rib-element and the tube, there is no
doubt that the communication of the heat is impeded thereby. Similarly there
is a possibility in the case of wrought iron tubes with ribs cast round them
that the ribs may separate from the wall of the tube during cooling so that
there will no longer be direct contact of the rib elements along the entire length
of the tube.
A high pressure ribbed tube according to this invention comprises a drawn
and seamless copper or wrought iron tube with rib elements slid over it and
soldered. These rib-elements themselves are flanged and stamped plates which
may be of copper or stamping sheet metal ("Stanzblech") as preferred. The
flanged portion of these plates has a certain length by means of which the
plates are kept at a determinate interval from one another. In addition, the
Hanged portion of the plates serves to strengthen or stiffen the tube to protect
it against bending.
The adhesion of the plates to and their intimate union with the tube itself
is effected by pickling the whole arrangement and tinning it in the complete
bath ("Vollbad") after the plates have been mounted on the tube. This
tinning may be effected as follows:-After the plates have been mounted on
the tube, the two end flanges of the copper tube are first hand soldered, or, in
the case of iron tubes, the flanges are screwed on tight, the tube is then pickled
and tinned, the source of heat employed being steam, superheated to 350°
to 400° C., which is passed through the tube.
High pressure ribbed tubes of this kind may be made in straight lengths and
joined together by flanges, and may act as heating elements when using high
pressure steam or as cooling elements (refrigerators) in refrigerating machines
with direct evaporation.

page_text: These high pressure ribbed tubes may also be used to form evaporative con-
densers for steam-engines or for refrigerating machines. For this purpose
several tubes such as described are arranged, in any number desired and in
any desired length, horizontally and one above another, and are connected
together by double or U-shaped bends so that a series of say 8, 10 or 12 of such
coupled high pressure tubes forms an element, at the upper union of which
the vapor or gas to be condensed enters, whilst the condensed matter leaves by
the lower union. According to the extent of cooling surface required two or
more elements are coupled together, the upper inlet unions being connected
together by a distributing pipe and the lower outlet unions by a collecting pipe.
An important advantage of evaporative condensers such as just described, over
evaporative condensers made of sinooth tubes, consists in the fact that the water
that flows over the ribbed tubes encounters a considerably larger surface for
its partial evaporation and consequent cooling than in the case of evaporative
condensers with smooth tubes having the same length, and hence it may be
cooled down as much as possible.
1611
1000
"
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
improvements in or relating to Steam Heating Apparatus and to
Condensing or Cooling Apparatus.
I, RODOLPHE RAU, 7, Kue Kuhn, Schiltigheim-Strassburg, Germany, Engineer,
do hereby declare the nature of this invention and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement:-
In steam-heating apparatus ribbed tubes are often used that are made entirely
of cast iron. These ribbed tubes possess the advantage, over smooth drawn
tubes, of having a considerably greater heating surface for the same length;
they have, however, the disadvantage that they offer but little resistance to
external blows or to internal water-blows caused by the condensation of the
steam. In more recent apparatus, for the sake of safety, cast-iron ribbed tubes
are employed only in connexion with low-pressure heating apparatus with ex-
panded steam, and wrought-iron tubes with ribs forced or cast on, for high-
pressure heating-apparatus.
In the case of wrought-iron tubes with ribs forced on, it is hardly possible
in practice to fix these ribs so closely on the walls of the tubes as to secure a
direct contact between the two bodies, and, since there is undoubtedly a layer
of air between such ribs and the tube, there is no doubt that the transmission
of the heat is impeded thereby. Similarly there is a possibility in the case
of wrought-iron tubes with ribs cast round them that the ribs may separate
from the wall of the tubes during cooling so that there will no longer be direct
contact of the ribs along the entire length of the tubes.
A high-pressure ribbed tube according to this invention is shown in the
accompanying drawings in which Fig. 1 is a sectional and an end elevation;
Fig. 2 is a side view of a tube and Fig. 3 represents several ribbed tubes arranged
one above another and connected together.
A ribbed tube according thereto comprises a seamless copper or wrought-
iron tube with ribs forced over it and soldered. These ribs themselves are
1

page_text: flanged plates which may be stamped from sheet copper or sheet-iron or cast
as preferred. The flanges of these plates have a certain length for the purpose
of keeping the plates at a certain distance from one another. In addition, the
flanges serve to strengthen or stiffen the tube to prevent it from bending.
The adhesion of the plates or ribs to and their intimate union with the tube
itself is effected by pickling the whole arrangement and tinning it in a bath
after the plates have been mounted on the tube. This tinning may be effected
as follows: After the plates have been mounted on the tube, the two end
flanges of the copper tube are first hard soldered, or, in the case of iron tubes,
the flanges are screwed on tight, and the tube is then pickled and tinned, the
source of heat employed being steam, superheated to 350° to 400° C., which is
passed through the tube.
High-pressure ribbed-tubes of this kind may be made in straight lengths as
is shown in Fig. 2, and joined together by Hanges, and may act as heating
elements when using high-pressure steam or as cooling-elements (refrigerators)
in refrigerating machines with direct evaporation.
These high-pressure ribbed tubes may also be used to form evaporative con-
densers for steam-engines or for refrigerating machines. For this purpose
several tubes such as described are arranged, as shown in Fig. 3, in any number
desired and in any desired length, horizontally and one above another, and are
connected together by double or U-shaped bends so that a series of say, 8, 10,
or 12 of such coupled high-pressure tubes forms an element, at the upper uniou
of which the vapour or gas to be condensed enters, whilst the condensed matter
leaves by the lower union. According to the extent of cooling surface required,
two or more elements are coupled together, the upper inlet unions being con-
nected together by a distributing pipe and the lower outlet unions by a collecting
pipe.
An important advantage of evaporative condensers such as just described,
over evaporative condensers made of smooth tubes, consists in the fact that the
water that flows over the ribbed tubes encounters a considerably larger surface
for its partial evaporation and the cooling thereby produced, than in the case
of evaporative condensers with smooth tubes of the same length, and therefore
the condensing effect is as great as possible.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed I declare that what
I claim is:-
1. A high pressure ribbed tube comprising a copper or wrought iron tube
over which flanged plates of copper or of iron are forced and soldered to the
tube or tinned together with the said tube.
2. An element suitable for use in an evaporative condenser consisting of a
number of high-pressure ribbed tubes according to the preceding claim placed
one above another and joined together by bends.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.

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