Steam Engine Cylinders, Covers, and Pistons.
Year: 1895

page_text: Date of Application, 22nd Nov., 1895
Complete Specification Left, 15th Aug., 1896-Accepted, 21st Nov., 1895
PROVISIONAL SPECIFICATION.
Heating Steam Engine Cylinders, Covers, and Pistons.
WILLIAM ISAAC LAST 3 Balmuir Terrace, Putney, Engineer, do hereby
declare the nature of this invention to be as follows:-
66
To increase the efficiency of steam engines by preventing the condensation that
takes place on the steam exposed surfaces and causes the losses due to what is
usually described as cylinder wall action." I do this by maintaining these
surfaces at a temperature such that during the cycle of the engine they never fall
below that of the boiler steam. Therefore to make up for the chilling during the
exhaust stroke I maintain a temperature in the jacketing fluid considerably greater
than that of the entering steam.
For a cylinder I cut a groove, preferably helical, in the bore and in the groove fit
a metal pipe, then fill in the unoccupied portion of the groove with metal or other
suitable material so as to obtain a smooth working surface, and also facilitate the
passage of heat from the pipe to the cylinder. Or I may use a pipe of such section
that it will exactly fill the groove. If the cylinder have a liner I may form the
groove in the exterior of the liner and then fit in the pipe coil as before; or I may
make a helical groove in the cylinder and into it fit the pipe coil and then force in
the liner; or I may omit the pipe and use the passage formed by the groove as the
channel for the heating fluid.
For a cylinder end or cover I may form in the steam face of it a groove,
preferably of spiral outline, in the groove fit a spiral or coil of pipe and stem or
close up so as to leave a smooth face as when treating a cylinder bore. Or I may
omit the pipe and fit on the cover a disc of copper or other material, which disc
may extend out into the cylinder cover joint. Or the spiral groove may be formed
in the back of the disc. When the groove is formed in the disc I may interpose
between the disc and the true cover a sheet of asbestos millboard or other poor
conductor of heat to prevent as far as possible the passage of heat from the disc to
the external cover.
Each face of the piston may be treated as a cover, but the asbestos insulation
should not be added.
The whole of these pipes or passages may be coupled up in series or otherwise
and then have forced through them high pressure saturated steam, hot water, oil,
caustic soda solutions, or superheated steam; the object being that such fluids,
which must be at a much higher temperature than the boiler steam shall maintain
the surfaces to which the pipes or passages are adjacent at the desired high
temperature. When the pipes are employed their small diameter or corresponding
dimension enables very high pressure jacketing steam or other fluid to be used
with safety, and the continuous nature of the circuit insures uniform heating
through the perfect circulation that can be secured. Without the pipes the
passages left, will insure the circulation when jacketing by superheated steam or
other fluids, and have sufficient strength when the pressure of the jacketing fluid is
moderate. The heating is most uniform however when it is done by a saturated
vapour at the correct temperature as is the case with high pressure steam.
The copper discs or covers where fitted are to assist in securing a uniform
temperature on the steam exposed faces of covers or pistons without the use of
such finely pitched spirals as would otherwise be desirable.
The jacket heating fluid may be circulated by a pump, or by gravity, or by a

page_text: "steam loop," and it may be heated in any suitable form of heater or boiler, or in
a coil or grid of pipe. Such heater may be placed in the ordinary boiler furnace,
or uptake, or flue, or it may be heated by a separate furnace. When using steam
or other vapour the pump etc. will be employed in forcing the condensed fluid back
into the heater for re-evaporation chiefly.
As the greater part of the usual losses are probably due to the condensation
upon the dull faces of the covers and piston it will in some cases be only necessary
to heat these surfaces in the manner described.
To convey the heating fluid to and from the piston, passages may be formed in
the piston rod or tail rod and the connections be made by flexible pipe or by
sliding pipes and packed joints, or by swinging tubular arms, or by packed
telescopic pipes. Or separate pipes may be led from the piston through glands in the
cover. One pipe or passage may however be sometimes used, this supplying
the piston heating fluid, the cooled fluid from the piston being delivered into the
cylinder through a spring loaded valve. Such valve can be arranged to discharge
either during the steam strokes or the exhaust strokes, this depending simply upon
whether it is arranged to open inwards or outwards.
In arranging the cylinder jacketing it is best to supply the heating fluid at the
two ends and withdraw it at the middle of the length, owing to the less heating
that is necessary at the centre.
Dated this 22nd day of November 1895.
Dating Steam Engine Cylinders, Covers, and Pistons.
1, WILLIAM ISAAC LAST, of 3 Balmuir Terrace, Putney, 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 :-
My invention has for its object to increase the efficiency of steam engines by
preventing the condensation that takes place on the steam exposed surfaces of
steam engine cylinders, pistons, and covers, which condensation causes the losses
due to what is usually described as "cylinder-wall action." I do this by
maintaining these surfaces, by the aid of highly heated fluids circulating through
passages within the metal immediately behind these surfaces, at such a high
temperature that even at the end of the exhaust stroke when they have experienced
to the utmost the chilling effect of the exhaust or the condenser, the surfaces are
still at a temperature at least as high as that of the boiler steam.
"
There is then no condensation on these surfaces and throughout the cycle of the
engine they remain dry, and so, provided all the exposed surfaces are treated,
the whole of the serious losses due to 65
cylinder-wall action are prevented.
To accomplish this the temperature of the jacketting fluid must be much higher
than has at present been attained and with efficient circulation. Saturated vapours
are the best fluids to employ on account of the uniform heating they give, but the
pressure necessary to maintain the requisite temperature where steam is the vapour
is much higher than the ordinary system of steam jacketting will safely withstand.
Jacketting with steam of a higher pressure than that of the working steam has
already been tried but the temperature of the jacketting has not been nearly
sufficiently above that of the working steam to maintain the cylinder metal surfaces
at the high temperature that I require, so that proportionately better results have
not been attained.
Without binding myself to the accuracy of the following figures but using them
to assist in explaining my meaning-we will assume the case of an engine supplied

page_text: with boiler steam at 100 lbs. pressure per square inch above atmosphere and at a
temperature of 338° F. and discharging into a condenser at 140° F., there is thus
a difference of temperature in the two strokes of 198° F., and to prevent the
cylinder surfaces, at the end of the exhaust stroke, from falling below the
temperature of the entering steam, i.e. 338° F. the metal behind those surfaces
should be maintained at a temperature of between 460° and 540°. These tempera-
tures represent steam at pressures of from 450 to 900 lbs. per square inch. It is
obvious that the metal cannot be heated to the required degree by a fluid that is at
a lower temperature than that required in the metal, and it will depend upon the
ratio of the heating surface of the coils to the cooling surface of the metal exposed
to steam, as to what excess of temperature in the heating steam is necessary to
secure the required surface temperature. Other saturated vapours instead of
steam may be used.
When hot liquids are used, or fluids that do not give off a large amount of heat
at a high temperature by a change of state, a very complete system of circulation
is necessary. Thus superheated steam, or hot oil, have failed when applied in
an ordinary jacket probably through the very partial and local heating that
they give.
To maintain the exceptionally high jacketting temperatures and good circulation
that I require, I employ the arrangements shewn and described in connection with
the attached drawings, in which :-
Figure 1 is a sectional plan of an engine cylinder covers and piston, prepared
according to my invention.
Figure 2 is a front view of the piston.
Figure 3 is a sectional elevation of a modified construction of cylinder, covers,
and piston.
Figure 4 is a sectional elevation of the piston in Figure 3.
Figures 5 and 6 are two sectional views of a modified form of piston for a
vertical engine.
Figure 7 is a detailed section of a portion of a cylinder liner.
Figure 8 is a detailed section of a portion of another liner and cylinder.
Figure 9 is a detailed section of a portion of a cylinder end or cover.
Figure 10 is a detailed section of a portion of another cylinder, cover, or
piston.
Figure 11 is a detailed section of a piston draining valve.
Figure 12 is a detailed section of another form of piston draining valve.
The cylinder C in Figure 1 is fitted with a liner on the exterior of which is
cut a continuous groove, and in the groove, which is preferably helical, is fitted a
metal tube as shewn in detail in Figure 7.
The small diameter of the tube permits the safe use of heating fluids of very
high pressure, while the continuous nature of the circuit provided, insures uniform
heating of the liner, and the good contact of the metal of the tube with that of the
liner facilitates the passage of the heat from the fluid in the tube to the liner.
In Fig. 8 is shewn a modification in which the tube is fitted into a groove in the
cylinder metal and a thin liner with a smooth exterior is then inserted.
In Fig. 10 is another modification in which no liner need be used, as the cylinder
metal is cast round the tube previously placed and secured in its correct position
in the mould. This method is particularly suited to the metal around the steam
passages, and is shewn applied in the front end of the cylinder shewn in Fig. 3.
At Z in Figs. 7 and 8 the groove is shewn but no pipe is inserted, a modification
that gives good circulation when the heating fluid is passed through the groove,
but is not suited for an extremely high pressure in the jacketing fluid.
arrangement at Z in Figure 8 is shewn applied to the liner and cylinder in Fig. 3.
For heating cylinder covers similar arrangements are applicable. The front
and back covers shewn in Fig. 1 have grooves turned in them, preferably spiral as
shewn in the piston face in Fig. 2, and in the groove is fitted a pipe through which
is circulated the jacketting fluid.
The

page_text: After the tube is in position the unoccupied portion of the groove may be filled
up flush, with metal or red lead cement or other material.
A. cover may be heated by a pipe coil, cast or placed in the metal of a lining
cover, as shewn in the back cover of Fig. 3 and in detail in Fig. 9.
To reduce external radiation from such a cover a sheet of asbestos millboard
may be inserted between the heated liner and the external cover, as shewn at X
in Fig. 9.
Such an inner cover, attached to the cylinder front end by counter-sunk screws,
is a convenient method of jacketting this portion.
The faces of the piston may be fitted in the same way as cylinder covers, and in
Figs. 1 and 2, one of these arrangements is shewn. In Figs. 3 and 4 a form of
cellular piston construction is shewn that insures good circulation and also gives, if
required, the necessary strength to resist an excessively high pressure in the
jacketting fluid. The piston in Figs. 3 and 4 is for a horizontal engine and the
arrows shew how by suitably disposed passages through the ribs the drainage and
circulation are secured. In the lower half of Fig. 4 the cells are reduced in
number as would be safe with a small piston.
In the lower half of the piston in Fig. 3 screwed stays are introduced to
strengthen the flat surfaces against a high jacketting pressure.
In Figs. 5 and 6 are shewn two sectional views of a cellular piston for a vertical
engine, in which the jacketting fluid entering and leaving by the pipes shewn is
caused by suitably arranged passages in the webs to circulate through the complete
series of cells as indicated by the arrows. The piston constructions shewn in
Figs. 3, 4, 5 and 6 can obviously be employed for jacketting covers.
For pistons and covers another modification in the construction is to form the
web as a spiral band thus leaving a continuous spiral passage to secure the desired
circulation and at the same time the necessary strength.
To supply the heating fluid to a piston, a rod, or rods, like the tail rod A shewn
in Fig. 1 may be employed. In this rod is a longitudinal passage a fitted with a
stuffing box a¹ and rough this gland works a tubular rod b rigidly connected to
the cylinder.
Through this stationary rod the heating fluid is introduced to the piston, and
after passing through the heating coils, or chambers in the piston, it may be
returned through a similar arrangement of sliding rod and joint.
The supply and return rods may be however arranged concentrically.
Independent rods are indicated at 661 in Fig. 5. Instead of the external connection
being made by a sliding gland joint, swinging arms may be used, or else flexible
tubing. The piston rod itself may however be used, by drilling it up as shewn in
Fig. 3, and fitting it with side passages each containing a valve; in the stuffing
ring or box is a passage for the jacketting fluid, and at the end of each stroke the
valves in the piston rod pass over this orifice and so pass some of the jacketting
fluid into the piston coil or cells, as indicated by the arrows.
The return of the
jacketting fluid may be similarly arranged, or it may be through a sliding tube
similar to Fig. 1. For the discharge of the cooled fluid from a jacketted piston it
is very convenient to deliver it into the cylinder, and this is the arrangement
followed in Figs. 1 and 3. At the outlet of the piston circuit a valve is fitted, that
will retain a sufficiently high pressure in the piston jacketting fluid and yet will
open when that end of the cylinder into which it delivers is opened to steam, but
closed during the exhaust stroke so as to save a wasteful blow through. Fig. 11
shows a section of one form of this valve, in position in a piston P. R is the body
of the valve, V is the valve and t is the passage through which the cooled fluid
enters the valve. The pressure of the jacketting fluid is supposed to be much
higher than that of the working steam, and tends to keep the valve closed.
the back of the valve V is a collar upon which presses the spring shewn, tending
to open the valve, but the spring is not equal to the task unless assisted by the
working steam pressure on the delivery end of the valve V.
At
In Figure 12 is shown a modified form of valve for this purpose, worked by the

page_text: difference of pressure on the two faces of the piston. Similar letters bave the same
meaning as in Figure 11, but m is a passage from one face of the piston, and n
from the other, y is a small plug or piston that receives the thrust of the spiral
spring shown, which is loading the delivery valve so as to maintain the pressure
in t. Under the variation of pressure in m and n during the strokes of the engine,
moves backwards and forwards a little, so putting greater compression on the
spring when m is the pressure side of the piston, thus stopping the delivery of the
cooled (but still very hot) jacketting fluid during the exhaust-stroke of the n side.
As the quantity of heating fluid required for a piston is not great, a simple
spring loaded valve on the delivery end of its heating coil or circuit may be used,
delivering into the cylinder but retaining the desired pressure in the coils or
heating chambers.
"
The jacket heating fluid may be circulated by a pump or by gravity or by a
steam loop" and it may be heated in any suitable form of heater or boiler or in
a coil or grid of pipe. Such heater may be placed in the ordinary boiler furnace,.
or uptake, or flue, or it may be heated by a separate furnace. When using steam
the pump or other circulating device will be employed in forcing the condensed
fluid back into the heater for re-evaporation.
The hot fluids that I may employ for supplying the heat to my circuits are :-
high pressure steam or water, oil, caustic alkaline solutions, but owing to its low
specific heat as well as the poisonous nature of its vapour, mercury is unsuitable
and I do not claim the use thereof as part of this invention.
By supplying the working steam in a superheated state the temperature of the
jacket steam may be reduced accordingly and by superheating the jacket steam its
pressure may be somewhat reduced. In any case the working steam should be.
supplied as dry as possible.
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 :-
1. In a steam engine, jacketting the cylinder, cylinder covers and piston with
steam water or other jacketting fluid of such temperature that the temperature of
the steam exposed surfaces shall, at the end of the exhaust stroke be at least equal
to that of the boiler steam, substantially as and for the purposes described.
2. In a steam engine, jacketting the cylinder covers and piston with steam water
or other jacketting fluid of such temperature that the temperature of the steam
exposed surfaces thereof, shall at the end of the exhaust stroke be at least equal
to that of the boiler steam, substantially as and for the purposes described.
3. The method of jacketting steam engines with heated fluid consisting in
constructing the cylinder, piston and covers with helical or spiral channels
imbedded in the steam exposed surfaces, through which channels fluid is made to
circulate that is heated to such a temperature that the steam exposed surfaces.
shall, at the end of the exhaust stroke have a temperature at least equal to that of
the boiler steam, substantially as and for the purposes described.
4. In jacketting steam engine cylinders pistons and covers in the manner referred
to in the first and second claims, the use of small metal pipes imbedded or
contained in grooves in the metal of the steam exposed surfaces of such parts for
the circulation through them of heated jacketting fluid at high pressure,
substantially as described.
5. In jacketting the steam exposed surfaces of steam ports and passages the
construction of channels or conduits for conveying the jacketting fluid by placing
in the mould, metal pipes, around which the metal is afterward cast, substantially
as described.
6. In jacketting steam engine pistons the employment of means whereby the
cooled or condensed jacketting fluid is discharged into the cylinder, substantially
as described.
7. In jacketting steam engine pistons the use of a valve device so arranged as

page_text: to establish a communication between the piston jacket and the supply of jacketting
fluid during one or more points of stroke, the valve being made to confine the
fluid within the piston cavities during the remainder of the strokes, substantially as
described.
8. When jacketting cylinder ends by a highly heated jacketting fluid the use of
an internal plate heated by such fluid, contained in passages in or behind the said
plate, which plate is insulated from the cylinder cover or end by a sheet of asbestos
millboard or other suitable non-conductor of heat substantially as described.
9. In steam engine pistons and cylinder covers or ends of cellular or similar box
construction heated by steam or other fluid, the provision of drainage passages
connecting the cells in series for the purpose of securing circulation through and
drainage of the chambers as described.
Dated this 14th day of A nonst 1906
ABEL & IMRAY,
Agents for the Applicant.