IMPROVEMENTS IN ROTARY ENGINES.
Year: 1883

page_text: LETTERS PATENT to William Frost of Manchester in the County of Lancaster
Engineer and Theophilus Thomas Bond of Luton in the County of Bedford
Engineer for an Invention of IMPROVEMENTS IN ROTARY ENGINES.
*PROVISIONAL SPECIFICATION left by the said William Frost and
Theophilus Thomas Bond at the Office of the Commissioners of Patents
on the 29th June 1883.
WILLIAM FROST of Manchester in the County of Lancaster Engineer and
THEOPHILUS THOMAS BOND of Luton in the County of Bedford Engineer.
"IMPROVEMENTS IN ROTARY ENGINES
"
Our invention relates to rotary engines and the object of our Improvements is
to construct an engine economical in the use of steam.
In applying our Invention to a high pressure compound engine we employ two
cylinders fitted with valve boxes, slide valves, jacketod steam piping and condensed
water cocks either self acting or worked by band also a sliding cover or division
plate lifted by cams and levers a little after the exhaust opens to allow the piston
to pass under it and the sliding cover is lowered a little previous to the admission
of steam betwixt it and the piston. The cylinders are placed in line and tho
pistons secured to bosses on the main shaft. The engine is designed to cut off at
any part of a revolution and the exhaust takes place at about seven-eighths
(7/8ths) of a revolution, opening a hinged valve fitted in a passage cast with the
cylinder and passing through a jacket cast with the steam pipe, through the valve
box into the low pressure cylinder. The piston in the low pressure cylinder being
at about three-eighths (3/8th) of a revolution and the capacity of this cylinder
being equal to about three fourths (3/4ths) of a revolution in the high pressure
cylinder, thus securing the whole of the steam to bring the high pressure piston
over the dead centre.
"
The low pressure cylinder exhausts into tho atmosphere at about seven-eighths
(7/8) of a revolution: the sliding covers are fitted in glands which bolt down
to flanges cast on the cylinders with ports inside and recesses for the packing
Pavice G1

page_text: materials secured by the glands. When the steam in the high pressure cylinder
is cut-off and the exhaust opened, the exhaust steam passes froin this cylinder into
the low pressure cylinder.
The engine as above described may be fitted with two or moro cylinders and
used as a condensing engino either for marine or land purposes.
In applying our Invention to simple high pressure ongines we employ two
cylinders and exhaust at about seven-eighths (7/8th) of a revolution into the
atmosphere.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Frost and Theophilus Thomas Bond in the Great Seal
Patent Office on the 24th December 1883.
WILLIAM FROST and THEOPHILUS THOMAS BOND
ENGINES"
"IMPROVEMENTS IN ROTARY
Our Invention has for its object improvements in rotary engines by which wo
economize fuel to a very large extent by working the steam several times over
as well as expanding the same in combination with a thorough system of steam
jacketting. Our engines takes less area than any other engines being proportioned
as the ratio of the diameter of a circle is to the circumference. The present
ordinary high pressure reciprocating engine exhausts into the atmosphere several
times to ours once-indeed we consider our ongines are so constructed that they
are what we call "Double Compound."
Figure 1 is a side elevation of our engine and bed. Figuro 2 is a plan of the
same. Figure 3 is an elevation of the low pressure end of the engine, and Figure 4
is an elevation of the high pressure end of the engine. Figure 5 is a part longi-
tudinal section on line E. F. Figure 6 is a cross section of the high pressure end
on line A. B. Figure 7 is a cross section of the low pressure end on line C. D.
Figure 8 is an elevation of the outside part of the low pressure cylinder cover in
halves, which is necessary, while Figure 9 is an elevation of the inside of the same
cover.
In applying our invention to a high pressure compound engine we employ two
or more cylinders; H is the high Pressuro cylinder with its valve box J and slide
valve L and sliding cover or lift and drop valve M. K is the low pressure cylinder
with its valve box N and slide valve O and sliding cover or lift and drop valve P.
In the case of the engine illustrated the cylinders H and K are placed in line with
the one main shaft running through the centre of each of the cylinders but they
may of course be placed out of line and worked with independent shafts, but in
either case the two cylinders would be connected with steam piping and the valves
of both engines would be worked and regulated in harmony with each other. The
lift and drop valves in the engine illustrated on the accompanying drawings are

page_text: worked by the counter weighted levers R for the high pressure, and S for the low
pressure cylinders from the eccentrics U and V upon the main shaft Q. The slide
valves are worked by the counter shaft T which receives its motion from the main
shaft Q through the connecting rod T¹ and disc crank T'. The pistons Y in high
pressure cylinder and Z in low pressure cylinder are secured to bosses on. the main
shaft Q as shown or otherwise.
The engine is designed to cut off at any part of a revolution and the exhaust
takes place at about soven eighths of a revolution opening a hinged valve g hung
in a passage or box G by the pin or other device g³. The steam passes from the
high pressure cylinder through this hinged valve g and passes along the internal
steam piping w which is surrounded or jacketted by the high pressure steam
pipe entering into the interior of the low pressure slide valve O then passing
through the cylinder feed port x mixes with the high pressure steam already in
the low pressure cylinder as hereinafter to be explained. The capacity of the low
pressure cylinder at three eighths revolution is equal to the capacity of the high
pressure cylinder at three quarters revolution, thus securing the whole pressure
of the steam to bring the high pressure piston from exhaust to inlet to admit high
pressure steam.
The engine herein illustrated cuts off at half revolution in the high pressure
cylinder H when high pressure steam is then admitted into the low pressure
cylinder K working double compound and is cut off when the low pressure
piston arrives at throe-eighths revolution. The oxhaust in high pressure cylinder
takes place slightly earlier than the three eighths cut off in the low pressure cylinder
and onters the low pressure cylinder as previously described. The exhaust into
the atmosphere from the low pressure cylinder takes place at about seven eights
of the revolution.
I will explain the action of the steam in the herein illustrated engine during
one revolution: Supposing the high pressure piston Y to be in the position as
indicated by the dotted lines i.e just sufficiently advanced in the direction of the
arrow to allow the lift and drop valvo M to come down into its position. The
high pressure steam is admitted through the port A until the high pressure piston
has travelled half a revolution when the steam is cut off. At this point the high
pressure steam is admitted through the port x out of the valve box Ñ into the low
pressure cylinder K and continued during three-eights of a revolution. At this
point ie at about seven eighths of a revolution in the high pressuro cylinder H tho
piston Y has just passed tho outlet port 2 which communicates with the low
pressure cylinder K when this partly used steam rushes through the hinged flap
valve g along the internal passage w and into the low pressure cylinder K mixing
with the high pressure steam which has already been admitted direct from the
boiler during three eights of a revolution in the low pressure cylinder aforesaid,
In the mean time the hinged valve g returns to its position by the help of a spring
or other equivalent and the low pressure piston Z continuing its course in tho
direction of the arrow until it passes into the atmosphere through the outlet 3
at about soven eighths of its revolution making the engine to work doublo
compound.
To work the engine as a single compound or double high pressure-we should
not need the valve g nor valve box G¹ the passage 2 would communicate direct
with the atmosphere as in the case of the passage 3 in the low pressure cylinder.
Neither should we require the double passage, but simply a direct communication
with each cylinder from the Boiler. We cut off the steam at any part of tho
revolution to work expansively. Also the valve O would be similar to the
valve L.
The lift and drop valves are fitted in glands 4 and 5 with suitable packing so
as to be kept steam tight. I also provide in the back of the lift and drop valves
an escape port 6 in the low pressure drop valve P as per dotted lines and 7 in the
high pressure drop valve M which enables all back pressure to escape from
the back of the pistons up through the top of the lift and drop valves into the

page_text: atmosphere. These valves being made hollow are used for lubricating matter also.
The pistons are kept tight by springs behind plates or other suitable means. The
main shaft Q is kept tight by suitably packed glands 8 and 9. The cocks 10
and 11 are for draining the condensed water and may be worked by hand or
Belfacting.
Our engines may be fitted with two or more cylinders and may be used as
condensing engines for either marine or land purposes.
Having now described our invention of improvements in rotary engines we
would have it understood that we do not confine ourselves to the exact details
herein set forth such for instance as the manner of working the valves or the
direction of the steam ports or passages as these and other details may be
considerably varied without departing from the substance of our invention, but
what we do claim is :-
First-The double compound rotary engine working with high pressure and
partly exhausted steam substantially as herein described.
Second-The compound rotary engine working with high pressure steam
substantially as herein set forth.
Third-The rotary engine illustrated on the accompanying drawings for either
high pressure or condensing engines.
In witness whereof I the said William Frost on behalf of myself and the said
Thomas Theophilus Bond have hereunto set my hand and seal this Twenty
Second day of December in the year of our Lord one thousand eight hundred and
eighty three.