Improved Apparatus for Superheating Steam.
Year: 1896

page_text: Date of Application, 17th Apr., 1896-Accepted, 23rd May, 1896
Improved Apparatus for Superheating Steam.
I, Dr. BENNO JAFFÉ, of 16 Salzufer, Charlottenburg, near Berlin, Germany
Manufacturer, 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 all existing steam superheating apparatus it has been the aim to keep the
steam as long as possible in contact with the heating surfaces that are acted upon
by the fire.
The simplest arrangement for accomplishing this purpose is the construction of
helically coiled tubes, having the greatest possible number of convolutions in a
given space. These coils exposed to fire heat have however only a short duration
as they easily get burnt through in particular when the working is interupted.
For obviating this disadvantage the pipe coils have been made of considerable
thickness, or they have been imbedded in fire clay, or in cast iron.
With these arrangements however an increased consumption of fuel is required
while the rapid burning away is not prevented.
Another disadvantage in the use of such pipe coils lies in that the number of
convolutions that can be included in a certain space is limited, as in bending the
pipes certain limits cannot be exceeded.
My present invention relates to a construction of superheating apparatus which,
while it is of simple construction and affords large superheating capacity in a small
compass, has been proved by experiment to afford a high degree of efficiency with
small consumption of fuel, and is of great durability. The construction of the said
superheating apparatus is shewn on the accompanying drawing; it consists of a
tube A into which is introduced a helical blade B having one or more helices the
convolutions of which form with the inner surface of the tube, one or more
corresponding helical channels.
The tube is preferably arranged in a vertical position in the furnace, the steam
being introduced into the helical passage, while the outer surface of the tube is in
contact with the flames and combustion gases. The helical blade can be formed
either by cutting the same out of a solid casting, or by directly casting it in its
helical form.
It will be readily understood from this construction that the steam in passing
through the helical passage will be exposed to the action of the fire heat for a very
considerable length of time in comparison with the length of the tube, and will
therefore become heated to a high degree.
Any particles of water still contained in the steam will, in passing round in the
helical channel, be thrown by centrifugal action against the surface of the tube,
and will thereby be effectually converted into steam, so that a supply of very dry
steam will be obtained.
As shewn on the drawing several such tubes A with their helical blades B can
be connected together by external bends. The pitch of the screw blades and the
number thereof can be varied according to the temperature required to be attained,
and the volume of steam to be superheated.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
Apparatus for superheating steam, consisting of a tube into which is introduced

page_text: a helical blade, the convolutions of which form together with the inner surface of
the tube a helical passage through which the steam to be superheated flows, while
the tube is heated externally, substantially as described.
Dated this 17th day of April 1896.
ABEL & IMRAY,
Agents for the Applicant.