IMPROVE- MENTS IN HIGH AND LOW PRESSURE CONDENSING ROTARY STEAM ENGINES
Year: 1864

page_text: LETTERS PATENT to William Hall, of Wilford Street, in the Town and
County of the Town of Nottingham, for the Invention of "IMPROVE-
MENTS IN HIGH AND LOW PRESSURE CONDENSING ROTARY STEAM ENGINES."
Sealed the 3rd May 1864, and dated the 4th January 1864.
PROVISIONAL SPECIFICATION left by the said William Hall at the Office
of the Commissioners of Patents, with his Petition, on the 4th
January 1864.
I, WILLIAM HALL, of Wilford Street, in the Town and County of the Town
of Nottingham, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN HIGH & LOW PRESSURE CONDENSING ROTARY STEAM ENGINES,"
to be as follows:-
The first part of my Invention is in rotary steam engines.
Fig. 1 on the Sheet containing my Drawings is an end elevation of the
engine with one of the covers removed shewing the piston and a portion of
the cover at the other end; also a portion of the abutment slide.
A is the cylinder; b, the piston keyed on the shaft c; g, a packing recessed
on the inside to receive a spring to keep it in contact with the cylinder; d,
the abutment slide; f, abutment slide box; f', a box for the valve spindle to

page_text: work in which is shewn in Fig. 2; h, the steam pipe; i, the exhaust pipe;
k, the exhaust port; is a valve for closing port k and opening the port m
(see Fig. 3); the valve is moved by the lever n, being connected to it by
means of a stud fixed in the valve and passing through the slot o (see Fig. 3)
into the exhaust chamber. Fig. 2 is a longitudinal vertical section through
the centre of the engine. A, the cylinder; b, the piston; c, the shaft; d,
cylinder covers; a", a", conical brass bearing fastened by a set screw in the
covers, which forms a gland for packing the shaft ; i, the exhaust pipe com-
municating with the chamber the stud m comes into for moving the valve n';
d, abutment slide; a', a', are two ports communicating with the space at the
top of the abutment slide, one of the ports opening to one side of the slide
and the other to the opposite side, as shewn at Fig. 6; n' is a valve long
enough to cover both the ports a', a¹, the valve n¹ having a spindle that works
freely through a guide. At a the guide is attached to the rod which passes
through a gland in the box for the purpose of shifting the valve n³, so as to
close the ports a¹, a¹, seperately or both of them at once; h¹ is the eduction
port; Fig. 3 is a view of the cover that is partly seen in Fig. 1 with the
valve removed shewing the ports m, k, and slot o, which all open into the
exhaust chamber. To produce a true surface for the valve / to move on the
cover is turned to receive an annular ring, which being truly fitted and
rivitted on the cover and afterwards turned, the valve is then cut out as
shewn at Fig. 4 and the stud m (see Fig. 2) is fixed firmly in it. Fig. 5 is a
plan shewing the abutment slide; p is a wrought-iron plate slotted to allow the
valve n¹ (see Fig. 2) to slide over the ports a¹, a'. Fig. 6 is a section (drawn
to a large scale) through Fig. 5 from a to b, the dotted lines shewing the port
open to the engine, as shewn in Fig. 1, one of the ports being covered by the
valve n'; o is a metal packing fitted round the top edge of the abutment slide
and held in their places by the wrought-iron plate p, being screwed to the
abutment slide as shewn in Fig. 2, the valve n¹ moving freely between the
packings and under the plate p, the abutment slide, the piston, and
packing are all of an exact length, so as to move freely but steam-tight
between the two covers, to compensate for the wear of the slide and piston end-
ways. The cover to the left hand in Fig. 2 has an india-rubber ring inserted
between it and the end of the cylinder which makes the joint and also allows
the cover to be screwed up until it comes in contact with the piston and
abutment slide.
The second part of my Invention consists of a rotary air pump of which
Fig. 7 is a cross section. The piston is constructed in the same way as the.

page_text: one described in the engine. The abutment slide d is a plain peice of metal
packed on the top edge, same as the one in the engine, but it has no ports in
it and it is longer than the piston, their being a groove in each of the cylinder
covers the same width as the slide is thick for the slide to work in, and each
cover is fitted with a brass bearing, the same as shewn in Fig. 2, one of the
covers having an india-rubber ring inserted between it and the cylinder, same
as the engine, to compensate for the wear of the piston and slide endways; o
are india-rubber valves covering a grating on each side of the abutment slide-
box, each valve serving as a delivery or stop valve, that depending upon which i
way the pump is driven; s is a chamber that the water is forced into, making
its escape through the overflow pipe t; is the condenser of cylindrical
form, and fixed high enough for the water to flow freely down the pipe w
into the pump. & is the injection pipe entering the condenser at one end, the
exhaust of the engine entering at the opposite end; the injection pipe runs
the whole length of the condenser and is perforated along its upper side and
the end nearest the exhaust of the engine with small holes to distribute the
water all over the condenser in the form of spray. Fig. 8 is a plan shewing
the inside of the chamber s with one of the india-rubber valves o removed.
The india-rubber valves are kept in their places by studs screwed into
the gratings with a washer and nut over them; d is the top of slide; <,
washers; o, india-rubber valves; o, grating or valve seatings.
The action of the engine is as follows:-The valve is put over the port m,
(see Fig. 3,) and opens the port k (see Fig. 1) and the valve n' over the port
a', a', (see Fig. 2); the steam is then turned on to the top of the abutment
slide, and passing through the port in the abutment slide into the space x, x,
"see Fig. 1," forces the piston round in the direction of the arrows, the under-
side of the slide being exposed to the port k, the pressure on the top keeping
it in contact with the piston until it has travelled so far round as to lift the
abutment slide into its recess again, which closes the port a¹, a', just before
the port opens to allow the steam to escape. I would here remark that by
reversing the valve and the valve n¹ the engine would go the reverse way
round, also that it can be used as a high-pressure engine, the steam being
worked expansively by the addition of a drop valve or any of the well-known
appliances for cutting off steam at any part of a revolution, and for an engine
that only revolves one way the two reversing valves and their appendages
would be dispensed with, also one of the ports in the abutment slide; it then
only requires the steam to be admitted at the pipe h through the port in the
abutment slide and exhaust through the cover at or through the cylinder

page_text: near to the abutment slide, as shewn at section, Fig. 9. To work the engine
singly it requires a fly wheel on the shaft, but with two such cylinders on one
shaft and the pistons set opposite each other the fly wheel could be dispensed
with.
The following is the action of the air pump :-The exhaust pipe of the
engine being connected to condenser, and the shaft of the air pump coupled to
the engine shaft and the pump charged with water, as shewn in section, Fig 7,
through one of the gratings, and having blown steam through the condenser to
form a vacuum, we now turn on the steam into the engine which moves
the pistons of the engine and air pump in the direction of the arrows, and as
the pistons move the atmospheric pressure keeps the slide d of the air pump in
contact with the piston and forms a vacuum in the space a. As soon as the
piston has passed the pipe w it forces the water through the right hand valve,
the water from the condenser then rushes into the space x, which increases in
area until the piston has lifted the slide into the box it works in. When the
piston has passed the slide the atmospheric pressure again forces the slide in
as the piston moves round, the same effect being produced whichever way the
pump is put in motion, when the pump is only required to go one way one of
the valves and grating are only required.
The third part of my Invention is the application of a governer to rotary
engines, the governor in place of being fixed perpendicular are fixed hori-
zontily on the shaft of the engine of which Fig. 10 is a view; c is the shaft,
the boss d being keyed on to it; the boss e is fitted on the shaft with a feather
so as to move freely, which box forms a camm for working a drop valve; the
camm g lifting the valve spindle o, at a fixed part of a revolution but allows
it to drop earlier or later, depending how far the governor has shifted the
camm on the shaft, between the bosses d and e there is a spiral spring strong
enough to keep them apart until the engine has attained the desired speed for
the governor to act on the camm.
Having now described the nature of my Invention, I wish it to be under-
stood that I do not confine myself to the proportions of the air-pump relative
to that of the engine has set forth in my Drawings; as the engine can be driven
at a much higher velocity than the air pump, their proportions would vary in
proportion to their relative speeds, and when such is the case the pump would
require to be driven by gearing or any of the well-known appliances for trans-
ferring motion from the engine to the air pump.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Hall in the Great Seal Patent Office on the
10th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HALL, of Wilford Street, in the Town and County of the Town of Nottingham;
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of January, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said William Hall, Her special licence that I, the said William
Hall, my executors, administrators, and assigns, or such others as I, the
said William Hall, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN HIGH AND Low PRESSURE CONDENSING ROTARY STEAM ENGINES,"
upon the condition (amongst others) that I, the said William Hall, my
executors or administrators, by an instrunient in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said William Hall, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, that is to say :--
The first part of my Invention is in rotary steam engines.
Fig. 7 in the Sheet containing my Drawings is a cross section of the engine
in its simplest form, consisting of a cylinder, piston, and abutment slide. The
cylinder has a cover at each end, with brasses inserted therein forming a bearing
for the shaft to work in. The piston is keyed excentrically on the shaft, and
rotates within the cylinder and between the two covers; the steam in this
case is not worked expansively; the engine has a dead centre, or, in other

page_text: words, when the piston is in a certain position the steam cannot act upon it,
it therefore requires a fly wheel to carry it past that point.
The same letters of reference on each Drawing will refer to the same parts
in all of them.
In Fig. 7a is the cylinder; b, the piston; c, the abutment slide, which
reciprocates in a slot that projects from the upper side of the cylinder; the
slot has a cover bolted over the top of it, so that the steam can impinge on
the under side of the cover and on the top edge of the abutment slide. d is
the shaft; e is a metal strip or packing, fitted in the piston, and kept in
contact with the cylinder by a spring between the piston and strip. The steam
is admitted at the port i, and passes through the port j in the abutment slide
into the space in-forcing the piston round in the direction of the arrow; the
pressure of the steam on the top edge of the abutment slide keeps it in
contact with the piston until the piston arrives at the bottom side of the
cylinder; the bottom edge of the slide is than exposed to the same pressure
as the top edge until the piston has lifted the slide into the slot it works in,
when the pressure of the steam at the top forces it into the cylinder again;
n is the eduction port; o are metallic packings, fitted round the top edge of
the slide, and are held in their places with a wrought-iron plate screwed to
the slide. The piston and slide are of an exact length, and to compensate for
the wear endways one of the cylinder covers has an india-rubber ring placed
between it and the cylinder, so as to admit of the cover being screwed up until
it comes in contact with the end of the piston; this engine when made on a
small scale is well adapted for donkey engines for pumping, or where a bigh
speed is required, as it will run smooth and steady from one thousand to three
thousand revolutions per minute.
Fig. 2 is an elevation of a rotary condensing engine and rotary air pump
with governors and valve for working the steam expansively and also a valve
for reversing the engine, which valves can be applied to a high-pressure non-
condensing engine in the same way as to a condensing engine. a¹¹ is the
engine; 6, the air pump; a', the condenser; d', a box containing a drop
valve, that the governor cam acts upon; e¹ is the cam, fitted with a feather on
the engine shaft, so as to move freely with the action of the governor.
The
boss is keyed fast on the shaft. g' is the induction pipe; h', steam chest ;
, driving pulley; 1, the fly wheel; k', the dead plate. The cylinder cover
marked has an india-rubber ring between it and the cylinder, the same as
described in Fig. 7.
Fig. 1 is an end view of Fig. 2, with the air pump any cylinder cover

page_text: removed, showing the two ports x, which opens into the steam chest that is
attached to the cover for a valve to work in for the purpose of reversing the
engine; the abutment slide in this case has no port in it; the port.i com-
municates with the steam chest.
Fig. 3 is a view of the cylinder cover with the steam chest attached and
the steam chest cover removed, showing the valve for reversing, which is
connected to the lever y for the purpose of shifting it over both the ports x,
which would stop the engine, or from over one port to the other, which would
reverse the engine. f is the valve, which is double-faced, and fitted steam-
tight between the steam chest cover and the cylinder cover. The steam
exhausts through the valve.
Fig. 4 is a view of the valve facing next to the cylinder cover. z is the
steam way; o¹ is a metal ring let into the valve facing with an india-rubber
ring behind it to keep the metal ring in contact with the cylinder cover, and
compensate for wear and expansion.
Fig. 5 is a section from g¹ to b¹ (see Fig. 3); is the cylinder cover; 1, the
steam chest cover.
Fig. 6 is a longitudinal vertical section of a part of Fig. 2. 1 is a double-
seated drop valve; o" are metal rings, let into the cylinder covers and ends of
piston, with india-rubber rings behind them that keep the metal rings in
contact with the piston and covers to prevent steam or air passing. n³ is a
brass that forms a conical bearing for the shaft to work in; it also answers
for a gland to hold a packing of hemp or other suitable substance. The
arrows show the direction of the steam.
The second part of my Invention consists of a rotary air pump, of which
Fig. 8 is a cross section consisting of a piston, cylinder, and abutment slide,
with covers and bearings for the shaft to work in, same as the engine, the
abutment slide having no port in it, and the top edge of the slide is exposed
to the pressure of the atmosphere, so that when there is a vacuum formed in
the cylinder the pressure of the atmosphere keeps the slide in contact with the
piston; p is a port for the water to pass through in connection with a grating
or seating for india-rubber valves to rest on; r are the india-rubber valves.
When the pump is only required to work one way one of the valves, seatings,
and ports can be dispensed with; s is the hot well; t, the overflow pipe, which
is higher than the top edge of the slide, so that it is always covered with water
to prevent air from getting into the pump; a¹ is the condenser ; v, the injection
pipe, perforated with small holes along its upper side, so as to distribute the
water all over the condenser in the form of spray. The condenser is

page_text: fixed high enough to allow the water to fall freely down the pipe w into the
pump.
Fig. 9 is a plan of the air pump, with one of the india-rubber valves
removed, showing the grating the valves rest on. There are two studs screwed
in the grating, which pass through the india-rubber to receive a washer and
nut to prevent the valves being forced away from the seating, but allows the
valves to rise sufficient for the water to escape from the pump.
The third part of my Invention consists in the application of a governor to
rotary engines fixed on the engine shaft, as shown in Fig. 2, for working a drop
valve by means of a cam connected to the governor. The cam has a graduated
projection upon it, so formed as to cut off the steam at a very early part of a
revolution, when the governors are open to their full extent, and at a later
part of a revolution as the governor closes. I would here remark that the
cam e' is fixed on the shaft, so as to always lift the drop valve just before the
abutment slide is lifted into the slot it works in, which causes the steam to be
cushioned a little between the top edge of the slide, and the cover over the
slot, so as to prevent the slide being thrown off the piston by the momentum
given to the slide when running at high speeds. The said cam can be used
for working the drop valve without the governor by being shifted with a
suitable lever, so as to allow the drop valve to fall at any part of a revolution.
There is a spiral spring on the engine shaft between the cam e' and the fast
boss f¹, strong enough to keep the governors closed until the engine has
obtained the required speed.
I wish it also to be understood that when two of the engines, the same as
described. in Fig. 1 to Fig. 7 on the Sheet containing my Drawings, are fixed
on one shaft with the piston set opposite each other, that the fly wheel can be
dispensed with, and also that the steam can be worked expansively without the
reversing valve, the ports in the engine being the same as shown in Fig. 7,
and that the reversing valve can be used without the expansion or drop valve,
the ports in the engine being the same as shown in Fig. 2; and when the
governors are used in connection with the reversing valve that the boss f¹
is fitted with a feather on the shaft, and the cam e' is twice the length, as
shown in Fig. 2, forming a right and left handed cam, there being a lever
connected to the boss f¹, so that the governors can be shifted on the shaft,
so as to bring either the right or left handed cam into operation.
Having described the nature of my Invention, I wish it to be understood
that I do not claim any of the well-known parts as my Invention, excepting
as combined for the purposes of this Invention; what I now claim as my

page_text: Invention is the application and use of the several arrangements herein set forth
and described in the first, second, and third parts of this Invention.
In witness whereof, I, the said William Hall, have hereunto set my
hand and seal, this Ninth day of May, in the year of our Lord
One thousand eight hundred and sixty-four.
WILLIAM HALL. (L.S.)