Improvements connected with the Re-heating of Steam in Steam Engines.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements connected with the Re-heating of Steam in Steam
Engines.
I, ENRI STEVEN, of St. Sebastian, in the Kingdom of Spain; Engineer do hereby
declare the nature of this invention to be as follows:-
It is well known that in steam engines during expansion and exhaust the cylinder
becomes cooled and consequently the live steam is cooled as soon as it enters the
cylinder. This cooling action being very considerable even in engines with jacketted
cylinders is one of the most important factors to be taken into consideration in the
consumption of steam or heat.
To overcome this disadvantage in the steam engine I provide for re-heating the
steam during its expansion in the cylinder.
The admission of the steam being effected in any ordinary manner by any method
of distribution I provide each side of the cylinder with an inlet (independent or not
of the steam distribution) through which a quantity of superheated steam is allowed
to enter the cylinder, the said steam being sufficient to ensure that the saturated
steam expanding in the cylinder preserves a temperature equal or superior to that
corresponding to its initial temperature so that, in spite of the expansion, the
temperature of the cylinder walls is not lowered whereby the partial condensation of
the steam during admission and expansion is avoided.
To introduce the superheated steam I convey it in a tube opening into the two
ends of the cylinder and provided at its central portion with an automatic distributer
furnished with a valve having two seats.upon which it alternately rests allowing the
superheated steam to pass between it and one of the seats.
As an example I will describe my invention as applied to a stationary steam
engine.
The steain, conveyed through a tube having a cock and a branch pipe, is superheated
by means of a small furnace adapted to heat a coil placed above a grate it then passes
through a second pipe to the distributer and enters the cylinder through one of two
pipes or tubes. The distributer contains a valve which can be applied against one or
other of two seats as above described and its displacement is effected solely by the
difference of the pressure of the steam at the ends of the pipes proceeding from the
distributer. Thus if steam be admitted into the cylinder through the pipe feeding
the left hand end of the same the steam in this pipe will have a pressure about equal to
that of the boiler whilst in the other pipe there will be a pressure equal to that of the
atmosphere or of the condenser. As a consequence the valve will be pushed back so as
to close the inlet into the latter pipe and will allow the superheated steam to enter
into the left hand end of the cylinder. This superheated steam will thus enter the
cylinder during the whole of the stroke in a rapidly increasing quantity on account of
the growing excess of the pressure of this steam over that of the expanded steam.
The increase of difference of pressure can at any time be moderated or regulated
by means of a cock or of any suitable valve regulated by hand or automatically at the

page_text: same time as the admission of steam to the cylinder. It is necessary to furnish
increasing quantities of superheated steam during expansion to prevent the rapid
drop in temperature which this expansion tends to produce.
Instead of superheated steam I can employ hot air and obtain similar results.
A spherical or ball valve serves to prevent the entrance of the steam admitted to
the engine into the coil but this valve may be dispensed with when the admission
steam is sufficiently dry.
The superheating of the stean could be effected in the flues or hearths of the
boilers supplying steam to the engine if the said boiler were placed sufficiently near
the steam engine. If not it is preferable to fit up the small separate furnace above
described near the engine. The gases of combustion of this small furnace can be
utilized for preliminarily drying the steam adinitted to the engine.
I may also employ as à superheater a small boiler furnishing superheated steam
at a pressure a little higher than that of the boiler which supplies the engine in order
that the superheated steam can pass into the cylinder during admission.
Dated the 31st day of December 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements connected with the Re-heating of Steam in Steam
Engines.
I, HENRI STEVEN, of St. Sebastian, in the Kingdom of Spain, 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 :-
It is well known that in steam engines the lowering of temperature which is
produced during expansion in the cylinder cools the latter and results in a
considerable loss of heat. To overcome this lowering of temperature I provide for
re-heating the steam during its expansion in the cylinder by an injection into the
said steam of fluid at a higher temperature than that of the steam which drives
the engine. The admission of the steam to an engine being effected in the ordinary
manner by any metliod of distribution; I provide each end of the cylinder with an
inlet through which a quantity of superheated steam is allowed to enter, the said
steam being sufficient to ensure the admitted steam which expands in the cylinder
preserving a temperature higher than that corresponding to its pressure during
expansion whereby the partial condensation of the steam during admission and
expansion is avoided.
To introduce the superheated steam I convey it through a tube opening into the
two ends of the cylinder and provided at its central portion with an automatic
distributer furnished with a valve having two seats upon which it alternately rests
allowing the superheated steam to pass between it and one of the seats.
To enable my invention to be fully understood I will describe it by reference to the
accompanying drawings, in which :-
Figure 1 is a sectional elevation illustrating my invention as applied, by way of
example, to a stationary steam engine:
Figure 2 is a longitudinal elevation of the cylinder and automatic distributer:
Figure 3 is a horizontal section of the cylinder and plan of the furnace hereinafter
described':
Figure 4 is a vertical section of the distributer drawn to an enlarged scale; and,

page_text: Figure 5 is a sectional olevation illustrating a modification.
The steain conveyed through a tube A. Figure 1, having a cock Band a branch
pipe C, can be superheated by means of a small furnace E adapted to heat a coil D
placed above a grate F; or the coil may be heated by any other suitable known
arrangement. The steam then passes through a pipe G. to the distributer H and
enters the cylinder through one of the two pipes or tubes I, J and I, J Figures. 2 and 3.
The distributer H (Figure 4) contains a valve Q which can rest against either the
seat P or the seat P. The displacement of this valve is effected solely by the
difference of pressure of the steam at the ends J, J of the pipes proceeding from the
distributer H. Thus, for example, if, as illustrated at Figure 3, steam be admitted
to the left hand end of the cylinder the steam pressure in the pipe I, J will be about
equal to that in the boiler, whilst in the other pipe I, J' there will only be a pressure
equal to that of the atmosphere or of the condenser. As a consequence the valve Q
will be pushed back and will leave the seat P and pass on to the seat P¹ so as to close
the inlet to the pipe I, J, thereby allowing the superheated steam to pass through
the pipe I, J and mix with the steam admitted to the cylinder. This superheated
steam will thus enter the cylinder during the whole of the stroke in a rapidly
increasing quantity on account of the growing excess of pressure of this steam over
that of the expanded steam.
This increase in the difference of pressure can at any time bo moderated or regulated
by means of a cock B or a suitable valve regulated by hand or automatically at the
same time as the admission of steam to the cylinder. It is necessary to furnish
increasing quantities of superheated steam during expansion to prevent the rapid drop
of temperature which this expansion tends to produce. The valve R serves to prevent
the entrance of the steam into the coil D but this valve may be dispensed with when
the steam admitted to the engine is sufficiently dry.
The superbeating of the steam can be effected in the flues or furnaces of the boiler
supplying steam to the engine if the said boiler be placed sufficiently near the steam
engine. If not, it is preferable to fit up the small separate furnace. above described
near the engine. The gases of combustion of this small furnace can be utilized for
preliminarily drying the steam admitted to the engine.
Figure 5 represents aa arrangement provided with a superheating apparatus
independent of the foundations of the engine and serving to effect a preliminary
drying of the steam admitted to the engine.
This apparatus comprises a sheet iron casing S provided with an inner refractory
brick lining within which is placed the superheater D provided with a supplementary
superheating tube V through which passes the steam conveyed, as in the herein before
described example, to the engine through the pipe G.
The gases proceeding from the furnace E and which have served to heat the coil D
are utilized before passing to the chimney, for heating a cluster of tubes U through
which the admission steam passes before entering the engine.
In some cases the hereinbefore described arrangement can be simplified by
dispensing with the valve Q, R and employing two superheaters each communicating
with one end of the cylinder so that a portion of the steam of each admission will pass
therein and become superheated in order, afterwards, to again enter the cylinder
during expansion.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The re-heating of the steam in the cylinders of steam engines after or during
the admission, by the mixture therewith of superheated steam or a sufficiently
heated and suitable fluid, substantially as hereinbefore described:
2. For carrying out the purpose of Claim 1, namely, to prevent as much as possible
the lowering of temperature which is produced in the cylinders of steam engines
when each volume of steam furnished by the distribution has expanded in acting
upon the pistou, the use of an injeo ting device communicating with a superheater fo

page_text: injecting a supplementary quantity of superheated stean or a suitable fluid at a
higher temperature than that of the steam supplied to the cylinder by the
distributing valve of the engine; each volume of steam furnished by the distribution
receiving in the cylinder a volume of steam at a higher temperature for preventing
it from becoming cooled and condensing during its expausion.
3. The herein before described apparatuses constituting novel means for automa-
tically superheating steam while in action in an engine, substantially as set forth and
as illustrated in the accompanying drawings.
Dated the 21st day of September 1897.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.