Improvements in and connected with Fluid Pressure Engines.
Year: 1899

page_text: Date of Application, 11th Dec., 1899-Accepted, 20th Jan., 1900
COMPLETE SPECIFICATION.
Improvements in and connected with Fluid Pressure Engines.
I, AUGUST WALDEMAR OFELDT, of Nyack, in the County of Rockland, State of
New York, United States of America, 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 relates to steam and other fluid pressure motors, and particularly
to motors of that class in which steam or other expansible fluid, after performing
work in a motor which may be termed a primary motor, is caused to pass through
a heater or vaporizer in which it imparts heat to a fluid or vapor of a nature such
that the pressure produced by it when so heated is greater than the pressure, at
the same temperature, of the working fluid employed in the primary motor; the
fluid or vapor thus heated and placed under pressure being then passed through
a secondary motor and caused to perform work therein.
The chief objects of my invention are, to more completely utilize for the pro-
duction of work, the heat contained in the exhaust steam or other fluid of fluid
pressure engines; and to produce simple and efficient apparatus, which will be
entirely automatic in its operation, and will prevent loss by leakage of the
secondary working fluid employed.
with a
According to my invention I provide the secondary motor
the exhaust from the primary motor
heating jacket, through which
or heater. I
the aforesaid vaporizer
is passed before passing into
also provide means for regulating the passage of the secondary work-
ing fluid through the heater or vaporizer: such means comprising a
body, over or around and in contact with which the exhaust steam or other
fluid is caused to pass so as to heat and expand or extend the said body in
accordance with the amount and temperature of exhaust fluid. A further feature
of my invention consists in employing a form of double gland and stuffing box
a chamber being
for the piston rod or other like part of a fluid pressure motor:
arranged between the two stuffing boxes of each double gland and stuffing box,
which chamber is in communication with an exhaust passage or condenser.
In order that my invention may be clearly understood and readily carried into
effect I will describe the same more fully with reference to the accompanying
drawing which shows, by way of example, a combined steam and naptha engine
constructed in accordance with my invention, the same being represented in
central vertical section, together with the naptha vaporizer, the naptha supply
tank, and the condenser.
In the drawing, 1 and 2 are the high pressure and low pressure cylinders,
respectively, of a compound steam engine. 3 and 4 are the valve chests of said
cylinders, and 5 is the crank shaft. It is not necessary to describe the details of
construction of this engine, as any form of steam engine, whether simple, double
compound, or triple expansion, may be employed.
6 is an engine cylinder, the working fluid used in which, when heated by the
exhaust from the cylinder 2, is able to perform efficient work in the cylinder 6.
Preferably, the working fluid employed in this cylinder 6 is a substance which at

page_text: ordinary temperatures, or at temperatures reached during the cycle of the engine,
is liquid, and the vaporizing temperature of which is lower than the vapourizing
temperature of the substance constituting the working fluid of cylinders 1 and 2.
If, as will usually be the case, steam is the working fluid employed in cylinders 1
and 2, then the working fluid of cylinder 6 may be a light hydrocarbon oil such as
that known as naptha and sometimes termed "gasolene." The use of naptha
rather than other volatile fluids, such, for instance, as ether, is preferable, because
naptha is cheap, is readily volatilized in a suitable heater by exhaust steam from
a steam engine, and is readily condensed to a liquid again. Even the exhaust
steam from a condensing engine working under a vacuum is sufficiently hot to
vaporize naptha.
The cylinders 1 and 2, with their pistons, piston rods, connecting rods, and
valve gear, constitute a primary motor; and the cylinder 6, with its piston,
piston rod connecting rod, and valve gear, constitutes a secondary motor. But,
as shown in the drawing, the primary and secondary motors may be built into a
single structure, all of the cylinders being placed over a single
crank shaft, and all the connecting rods being connected thereto; and the
cranks being arranged so as to balance each other and produce a uniform turning
action. In the drawing, the three cranks are set at angles of 120 degrees.
The cylinder 6 is provided with a steam jacket 7 completely surrounding the
said cylinder and communicating with the exhaust space of the low pressure
steam chest 4 through an opening 8. All of the exhaust of the primary motor
therefore passes through the steam jacket surrounding the cylinder of the
secondary motor, directly after leaving the primary motor, and when it is at its
highest temperature. From the side of the jacket 7 opposite the entrance open-
ing 8 a pipe 9 leads to a vaporizer or heater 10. This vaporizer or heater consists
of a closed tank supported from the top by an outer frame or casing 11, and has
inside it a series of tubular return bend coils 12. The exhaust pipe of the
primary motor is arranged to discharge the exhaust, after it has passed through
the jacket 7, into the interior of the said tank and around these coils 12.
Beneath the vaporizer 10 is a tank 13 containing the liquid which, when
vaporized, becomes the working fluid of the secondary motor. As already stated,
this liquid is preferably naptha. This liquid is forced from the tank 13 into the
coils 12 by means of a suitable force pump which may be driven from the crank
shaft of the engine; and inasmuch as it is not desirable to permit leakage of
naptha because of its smell and because of its combustible nature, this pump is
preferably placed within the tank 13 itself. 14 is the said pump. It is preferably
an ordinary plunger pump of simple construction. A plunger rod 15 passes
through a stuffing box in the top of the tank 13, and is connected by a connecting
rod 16 to a crank pin 17 on the crank shaft 5 of the engine. The discharge pipe 18
of this pump is connected to an automatically operated regulating valve 19, the
operation of which will be hereinafter described. From this regulating valve, a
pipe 20 leads to the lower end of the coils 12 in the vaporizer. The pipe 20 has
in it a return bend, as shown, to allow for its expansion and contraction. It
has also a check valve 21.
Naptha, or other suitable liquid, forced by the pump 14 into the coils 12 and
there vaporized, passes through a pipe 22 at the top of the vaporizer into the
valve chest of the cylinder 6. When exhausted from this cylinder, the naptha
vapor passes through a pipe 23 into cooling coils in a condenser 24; and the
condensed liquid flows back into the tank 13 through a pipe 25. If desired, the
exhaust steam, after passing through the vaporizer 10, may be passed through
other coils of the condenser 24 and condensed therein. The capacity of the
vaporizer or heater and of the cylinder 6 may be so proportioned, however, that
practically all of the exhaust steam may be condensed in the vaporizer 10, its
heat being transferred to the naptha.
It is important that the rate of flow of the naptha or other secondary fluid
through the coils of the vaporizer 10 shall be regulated automatically according

page_text: the work being done by the engine, that is to say, according to the quan
emperature of the exhaust steam or primary working fluid which passes through
he vaporizer; otherwise a greater or less quantity of unvaporized liquid will be
arried over into the secondary motor. For this purpose I employ a rod 26, of
naterial having a comparatively high co-efficient of expansion, such as copper.
This rod is located within the vaporizer, and is secured to the upper end thereof,
nd it passes through a stuffing box in the bottom of the vaporizer, and is connected
The lever 27 is connected to the valve
o the motion-multiplying lever 27.
tem 28 of the automatic regulating valve 19. This regulating valve has a by-pass
passage 29, adapted to be closed partly or completely by a plunger 30 connected
to the valve stem 28. When comparatively little exhaust steam is flowing into
the vaporizer, so that the temperature therein is comparatively low, and the rod 26
comparatively short, this by-pass passage is practically fully open and com-
paratively little naptha is forced by the pump 14 into the coils 12, the greater
portion of the naptha being returned to the tank 13 through the by-pass passage 29.
But as the quantity of exhaust steam flowing into the vaporizer 10 increases,
and the temperature therein rises, the rod 26 expands moving the plunger 30
downward and partly or completely closing the by-pass passage 29, thus increasing
the quantity of naptha flowing into the coils of the vaporizer 10.
The passing of the entire exhaust of the primary motor through the heating
jacket surrounding the cylinder of the secondary motor, before such exhaust steam
enters the vaporizer, is an important feature of my invention, because it permits
a maximum exchange of heat between the naphtha and the steam and moreover
insures the maintenance of the naptha gas at the highest temperature at the place
where it is most essential that the naptha shall have its highest temperature, viz.,
in the cylinder of the secondary motor. But heretofore only a comparatively small
proportion of the exhaust of the primary motor has been placed into the jacket
of the secondary motor, the greater portion of the exhaust passing directly into a
vaporizer; nor has provision been made, heretofore, for securing continuous and
rapid circulation in the jacket of the secondary motor. In my engine, since the
entire exhaust of the primary motor passes through the jacket of the secondary
motor, the cylinder of the secondary motor is heated to the maximum temperature
possible, and the circulation through the jacket is rapid and continuous."
The operation of the engine is as follows:-
When steam is first admitted into the cylinders 1 and 2, the crank shaft 5
commences to revolve, the exhaust steam passing through the jacket of cylinder 6
into the interior of the heater or vaporizer 10. The heat of the steam causes the
rod 26 to expand somewhat, and to thus partially close the by-pass passage 29
of the valve 19. The pump 14 therefore forces naptha into the coils 12 of the
vaporizer. The naptha in said coils, being vaporized by the heat of the exhaust
steam, passes into the cylinder 6 and performs work therein, afterwards exhausting
into the condenser 24 and flowing back into the tank 13. The naptha motor will
commence to do work effectively after the crank shaft has made two or three
revolutions. When the naptha gas enters the cylinder 6 it is heated to a consider.
5 able extent by the exhaust steam in the surrounding jacket, so that the mean
effective pressure in said cylinder is maintained as high as possible, and any
particles of liquid naptha carried over with the gas are vaporized.
In motors employing naptha which is vaporized by passing through coils heated
by a flame, trouble is often experienced because the intense heat of the coils
50 converts a portion of the naptha into a fixed gas. But the more moderate heat of
exhaust steam does not produce this difficulty. Consequently, a vacuum pump
may be used in connection with the naptha motor, just as such a pump is ordinarily
used in condensing steam engines.
The rod 26, by expanding or contracting according to the quantity of exhaust
55 steam flowing through the vaporizer, and according to the temperature in the
vaporizer produced by such steam, adjusts the valve plug 30, and so regulates the
amount of naptha flowing into the cylinder 6 in accordance with the work being

page_text: done by the engine. The passage of too great a quantity of naptha into the
vaporizer is thus prevented.
The naptha cylinder 6, and its valve chamber, have double glands and stuffing
boxes 31, each having a small chamber between the glands. A pipe 32 carries
any naptha which may collect in these chamber, into the exhaust pipe 23. This
construction is important, as the lower stuffing box, being free from pressure,
effectively prevents leakage of naptha around the piston rod.
A pipe 33 communicating with the tank 13, serves to convey any gas which may
collect in the top of said tank into the furnace of the boiler supplying steam to the
cylinders 1 and 2.
'
17
I do not limit myself to the use of steam in the primary motor, or to the use of
naptha in the secondary motor; nor do I limit myself to the use of motors of the
reciprocating type or of the same type, or connected to the same crank shaft, or
with cylinders arranged side by side. The ordinary motor may be a motor of the
explosive or internal combustion type. Moreover the construction and operation
of the device for regulating the flow of naptha into the vaporizer may be varied;
or I may employ any other suitable means for regulating the said flow.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The combination with a primary fluid pressure motor and a heater adapted
to be heated by the exhaust from said motor, of a secondary fluid pressure motor
operated by a substance vaporized in the said heater and provided with a heating
jacket through which the whole of the exhaust froin the primary motor passes on
its way to the said heater, substantially as described.
2. The combination with the heater of means for passing through the same the
substance to form the working fluid for the secondary motor, and of means for
regulating the flow of said substance to the heater in proportion to the work of
the primary motor, substantially as described.
3. In means for regulating the supply of working fluid to a secondary motor, an
'expansible body the length of which varies in accordance with the temperature of
the exhaust from a primary motor, substantially as described.
4. The combination with a fluid pressure motor and a vaporizer in connection
therewith of a supply tank and a pump within said tank operated by the motor to
force fluid from the tank into the vaporizer, substantially as described.
5. In a fluid pressure engine the combination with a chamber exposed to
pressure of the working fluid and having a movable member projecting therefrom
of a double packing or stuffing box, through which said member passes, having a
chamber between the said boxes and means for carrying off any fluid reaching
said chamber, substantially as described.
6. A fluid pressure engine having its parts constructed arranged and combined
'to operate substantially as described with reference to the accompanying drawing
for the purposes specified.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.