CERTAIN IMPROVEMENTS IN STEAM ENGINES AND ROTARY PUMPS
Year: 1864

page_text: LETTERS PATENT to Thomas Greenhalgh, of the City of Manchester,
Yarn Agent, for the Invention of "CERTAIN IMPROVEMENTS IN STEAM
ENGINES AND ROTARY PUMPS."
Sealed the 12th May 1865, and dated the 28th November 1864.
PROVISIONAL SPECIFICATION left by the said Thomas Greenhalgh at
the Office of the Commissioners of Patents, with his Petition, on the
28th November 1864.
I, THOMAS GREENHALGH, of the City of Manchester, Yarn Agent, do hereby
declare the nature of the said Invention for "CERTAIN IMPROVEMENTS IN STEAM
ENGINES AND ROTARY PUMPS," to be as follows:-
The first part of my Invention is applicable to rotary steam engines, and it
consists in applying a segmental shaped piston to an annular cylinder, to this
piston is cast or fixed a toothed wheel gearing into another wheel fixed on the
shaft to be driven; a valve is made to open and close at each revolution of the
piston, and the ingress and exhaust ports for the steam are opened and closed
alternately by suitable levers and valves.
A modification of my Invention consists in connecting the segmental piston
above referred to to a lever fixed on an axle concentric with the annular
cylinder.
The above combinations may be used as rotary pumps.
The second part of my Invention is applicable to the semi-rotary steam
engines for which Letters Patent were granted to William Martin and

page_text: Joseph Hodgson on the Thirty-first March, One thousand eight hundred and
sixty-four, No. 798, and it consists in casting or fixing toothed wheels to the
segmental pistons referred to in the Specification of the said Patent, which
toothed wheels gear into other toothed wheels or pinions fixed to separate
driving shafts, which may be coupled by cranks and rods or by gearing.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Greenhalgh in the Great Seal Patent Office on the
27th May 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
GREENHALGH, of the City of Manchester, Yarn Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of November, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Greenhalgh, Her special license that I, the said Thomas
Greenhalgh, my executors, administrators, and assigns, or such others as I, the
said Thomas Greenhalgh, 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 "CERTAIN IMPROVE
MENTS IN STEAM ENGINES AND ROTARY PUMPS," upon the condition (amongst
others) that I, the said Thomas Greenhalgh, my executors or adminis-
trators, by an instrument 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 Thomas Greenhalgh, 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 applicable to rotary steam engines and
rotary pumps, and it consists in applying a segmental shaped piston to an
annular cylinder; to this piston is cast or fixed a toothed wheel gearing into

page_text: another wheel fixed on the shaft to be driven; a valve is made to open and
close at each revolution of the piston, and the ingress and exhaust ports for
the steam are opened and closed alternately by suitable levers and valves.
A modification of my Invention consists in connecting the segmental piston
above referred to to a lever or wheel fixed on an axle concentric with the
annular cylinder.
The second part of my Invention is applicable to the semi-rotary steam
engines for which Letters Patent were granted to William Martin and
Joseph Hodgson on the Thirty-first of March, One thousand eight hundred
and sixty-four, Number 798, and it consists in casting or fixing wheels to the
segmental pistons referred to in the Specification of the said Patent, which
wheels are fixed to separate shafts, and coupled to the fly wheel shaft by
cranks and rods or by gearing.
And in order that my Invention may be fully understood and readily
carried into operation, I will proceed to describe the two accompanying
Sheets of Drawings, reference being had to the figures and letters marked
thereon.
On Sheet 1, Figure 1 represents one of my improved rotary steam engines"
or rotary pumps. a is an annular cylinder in which the segmental piston b
fits and rotates, this piston is provided with segmental packings c, c, and with
end packings to fit the bottom and lid of the cylinder; the piston 6 is cast or
fixed to the internal toothed wheel d, gearing into the pinion e keyed on the
fly wheel shaft f; to the shaft f is fixed a cam or tappet, as shewn in Figure 2,
for working the slide valve g; and the cylinder is provided with steam and
exhaust valves and ports, as in rotary engines of the ordinary construction.
As soon as the piston has passed beyond the end of the valve,g, the valve is
suddenly closed, and the steam is then admitted between the valve and the
piston, and turns the piston round; as soon as the piston has performed nearly
one revolution, the valve g is raised to allow the piston to be carried past the
valve g by the momentum of the fly wheel.
Figure 2 is a front view, and Figure 3 an edge view of another of my
improved rotary steam engines or rotary pumps. a is an annular cylinder, as
shewn in Figure 1; and 6 is a segmental piston connected to or cast with the
wheel d, which is keyed on the fly wheel shaft f; the valve g is opened and
closed to allow the piston 6 to pass by the cams h on the fly wheel shaft, these
cams work the rods i jointed to the double levers j, connected by links k to
the cross head 1, in which is fixed the spindle g' of the valve g. Another cam
or tappet is also fixed to the shaft f to work the slide valve m, by which the
ingress and exhaust ports of the steam are opened and closed alternately. In

page_text: order to keep the joints of the wheel d steam-tight with the cylinder, I have
applied packing rings s acted upon by springs on each side, as shewn in
Figure 3.
On Sheet 2, Figure 4 is a front view, and Figure 5 a transverse section of
a semi-rotary steam engine constructed according to my Invention. a is the
annular cylinder, and b, b', are two segmental pistons similar to those described
in the Specification of Letters Patent granted to William Martin and Joseph
Hodgson, on the Thirty-first day of March, One thousand eight hundred and
sixty-four, Number 798. The segmental pistons b, b¹, are fixed to the
wheels d, d', which are keyed on the shafts f,f¹; these shafts pass through
stuffing boxes o, o¹, and they revolve in suitable bearings p, p¹; the end of the
shaft f fits in a socket in the end of the shaft f¹, to insure the working in line
with each other; the wheels d, d', are kept steam-tight by the packing rings s,
as in Figure 3, and by the ring s¹. The steam is alternately admitted between
the pistons and exhausted through the ports t, t'. When the steam has been
admitted at the port t, it forces asunder the pistons 6, 61, which then perform
nearly half a revolution in the direction of the arrows; and when they arrive
near the port t¹ fresh steam is admitted at that port to force the pistons back
again.
The alternate to-and-fro motion of the shafts f, f', is converted into a rotary
motion by cranks and rods or by wheels.
Having thus stated the nature of my Invention, and described the manner
of performing the same, I declare that I claim the improved arrangements of
machinery forming rotary steam engines or rotary pumps, as. shewn and
described in reference to the various Figures on Sheet 1, and particularly the
mode of connecting the segmental piston to the fly wheel shaft.
And, secondly, the improved mode of constructing semi-rotary steam
engines, as shewn and described in Figures 4 and 5 on Sheet 2.
In witness whereof, I, the said Thomas Greenhalgh, have hereunto set
my hand and seal, this Twenty-fourth day of May, One thousand eight
hundred and sixty-five.
:
THOMAS GREENHALGH. (L.S.)
THOMAS GREENHALGH.
(L.S.)