Year: 1892

page_text: 1. In apparatus for converting fluid pressure into mechanical work and vice
vers, the application of two rotary pistons in the same cylinder as described, each
of these pistons being mounted on the same axis, but capable of revolving at
variable speeds substantially as and for the purposes herein set forth.

page_text: Date of Application, 3rd June, 1892
Complete Specification Left, 3rd Mar., 1893—Accepted, 2nd June, 1893
PROVISIONAL SPECIFICATION.
Mechanism for the Conversion of Fluid Pressure into Mechanical
Work and vice-versa.
ROBERT BEST HELLIWELL Consulting Engineer 7 Sandown Terrace
Wavertree Liverpool do hereby declare the nature of this invention to be as
follows:-
My invention has for object the construction of mechanism which shall convert
the energy of fluid pressure into mechanical work with greater efficiency than has
hitherto been effected also by means of this same mechanism to generate fluid
pressure with a less expenditure of power by which I mean the pumping of a liquid,
the compressing of air &c.
Also the object of this invention is the measuring of fluid passing through it.
Having stated the object of my invention I will now describe the mechanism by
which it is to be effected. When applied to the conversion of steam pressure into
mechanical work it may be termed a rotary engine whose construction is as follows.
Within a cylinder (of any required size) are two pistons, not reciprocating, which
rotate in the cylinder their axis of rotation being identical with the axis of the
cylinder. The form of these pistons, when viewed from the end of the cylinder, is
a segment of a circle (of the required length) radial lines forming the two faces.
Each piston is attached to a centre shaft, the one direct, the other to a sleeve, but
both terminating in a similar shaft extending through their respective ends of the
cylinder. These pistons are independent of each other, that is they can be made
to revolve at different speeds in the same cylinder and on the same axis. Each
piston forms a barrier to the passage of steam and extends from the centre to the
periphery. Upon each piston-shaft (outside the cylinder) an oval or eliptical gear,
with centre of revolution at one end and of the required proportions, is keyed fast.
These gears engage directly with similar ones fixed on a shaft (the driving shaft of
the engine) having its journals provided for by an extension from the cylinder
heads or otherwise, as desired. The gears upon the driving shaft are keyed with
their long sides opposite to each other and cannot alter their relative position.
They engage with those on the piston-shafts so as to run harmoniously, the long
side of one engaging with the short side of the other. Upon the driving shaft is
the usual fly wheel.
Now, with the exception of the position of steam ports the whole of the
mechanism, necessary for the comprehension of the invention has been described,
the action is as follows. Suppose (in order to observe the motion of the pistons the
one with the other) the driving shaft be turned, it will then be seen that each piston
will alternately travel faster and slower than the other, in this manner, one piston
will travel say four fifths of a revolution while the other is travelling one fifth
when the latter will next travel four fifths while the former only travels one fifth,
and so on, both pistons always going in the same direction, each alternately having
a purchase over the other. It will now be seen that the position of the steam port
must enter the cylinder (at the point where the pistons have approached close to
one another) and terminate according to whether steam is to be used expansively
or not.
I may now say that each piston in turn acts as a steam valve (the slow travelling
piston) and when it has travelled its one fifth revolution steam begins to be
admitted on the side from which it is travelling, of course being cut off on the
other side.
The exhaust port is in a similar position being open to the area, between the
pistons, that is diminishing and closed, by virtue of the position of pistons, to

page_text: the expanding area. I may add that the teeth of the aforementioned eliptical
gears are constructed with their centrelines radial to the axis of revolution there-
fore rendering it impossible for the leader to leave the follower.
Dated this Second day of June 1892.
ROBERT BEST HELLIWELL.
COMPLETE SPECIFICATION.
Mechanism for the Conversion of Fluid Pressure into Mechanical
Work and vice-versa.
I, ROBERT BEST HELLIWELL of 7, Sandown Terrace, Wavertree Liverpool in
the County of Lancaster, 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 the construction of mechanism which shall convert
the energy of fluid pressure into mechanical work with greater efficiency than has
hitherto been effected, also, by means of this same mechanism, to generate fluid
pressure with a less expenditure of power, by which I mean the pumping of a liquid,
the compressing of air, etcetera. Also, the object of this invention is the measuring
of fluid passing through it.
Having stated the object of my invention, I will now describe the mechanism by
which it is to be effected. When applied to the conversion of steam pressure into
mechanical work, it may be termed a rotary engine whose construction is shown on
the accompanying drawings, in which :-
Figure 1 is a side elevation of the engine;
Figure 2, a side elevation of one of the rotary pistons ;
Figure 3, an end elevation of the same;
Figure 4, a side elevation of the other pistons, and
Figure 5, an end elevation thereof.
In these figures, A is the bed plate of the engine, B the upright frame, C the
main shaft, D the fly wheel, and E the steam cylinder. In this cylinder, which is
of the required size according to horse power required, are two pistons F and G,
which do not reciprocate like an ordinary engine piston, but rotate in the cylinder E,
their axis of rotation being identical with the axis of the said cylinder. The form
of these pistous, when viewed from the end of the cylinder, is a segment of a circle.
They extend the entire length of the cylinder and are each divided in the centre, as
indicated in Figures 2 and 4, whereby the two parts may be thrust outwards by
thrust springs or other suitable device, so as to fit tightly between the two cylinder
ends, and being steam tight, are capable of being rotated by applying pressure on
either side. Each piston is mounted on a centre shaft H, the one G fixed thereon
direct, Figure 4, the other F attached to sleeves H', which are mounted on and are
capable of rotating independently of H. The solid end of one of the sleeves H',
and the shaft H (which are preferably of the same or about the same diameter)
extend through opposite ends of the cylinder. It will be seen, therefore, that these
pistons F and G are independent of each other, that is, they can be made to revolve
at different speeds in the same cylinder and on the same axis. Each piston forms a
barrier to the passage of steam and extends from the centre to the periphery.
They may each be made in two parts as shown and provided with springs f and g
or other suitable device to keep then pressed against the inner circumference of the
cylinder. Upon the piston shaft H and sleeves H', an oval or elliptical variable
speed gear of the required proportions is keyed fast outside the cylinder. These
gears, which consist of the wheels I and J, engage respectively with similar
wheels K and L on the main shaft C. The gears are keyed upon the respective
shafts, preferably in the relative positions shown on the drawing, and they cannot
alter their relative positions to each other. The wheels of the shaft C engage with

page_text: those on the piston shaft H and sleeve H' so as to run harmoniously, the long radius
of one engaging with the short radius of the other alternately.
With the exception of the position of steam ports, the whole of the mechanism
necessary for the comprehension of the invention has now been described, and the
action is as follows:-
Suppose (in order to observe the motion of the pistons, the one with the other) the
driving shaft C be rotated, it will be seen that each piston F and G will alternately
travel faster and slower than the other in the following manner-one piston will
travel say of a revolution, while the other is travelling, when the latter will
next travel, while the former only travels and so on, both pistons always going in
the same direction, each alternately having a purchase over the other.
It will now
be seen that steam must enter the cylinder through the port M at that period when
the pistons have approached close to one another, as shown in Figure 1 and must be
cut off sooner or later according to whether steam is to be used expansively or not.
Each piston in turn acts as a steam valve, and each is in turn a slow and a quick
travelling piston. When piston F has reached the position indicated in Figure 1,
steam is admitted through port M on the opposite side to that in which the piston is
travelling; of course being cut off from the other side of the said piston. The exhaust
port N is at the same moment open so that the piston F is driven round the cylinder
in the direction of the arrow by the pressure of the live steam entering through the
port M, while the steam occupying the space on the other side of the piston F is
released through the exhaust port N. In the meantime, the piston G is driven
slowly round until it closes the steam port M, thus itself cutting off the steam
supply, then, when it occupies the position previously occupied by F, steam is
admitted, G becomes the driving piston and F the driven one, and so on alternately.
The aforesaid elliptical gears are constructed with their teeth radial to the axis of
revolution, therefore rendering it impossible for the wheels to come out of gear.
The passages O are auxiliary passages for admitting a larger or more copious
supply of steam or liquid to the cylinder than the port M is capable of. These
passages are controlled by the valve P.
I have described one way in which my invention may be carried into effect when
applied to steam motors, but it is obvious that once given the general idea,
compressed air, water or other liquid may be employed instead of steam, also various
alterations in the construction may be made without departing from the principle
of my invention. Likewise it is evident that, by making but slight alterations, the
apparatus can be used as a pump or an air compressor, and even for measuring
fluids or other like purposes.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is―
1. In apparatus for converting fluid pressure into mechanical work and vice
vers, the application of two rotary pistons in the same cylinder as described, each
of these pistons in the same cylinder as described, each of these pistons being
mounted on the same axis, but capable of revolving at variable speeds substantially
as and for the purposes herein set forth.
2. The arrangement of engine with duplicate rotary pistons in one cylinder
substantially as described and shown, whether the cylinder be horizontal, vertical
or inclined.
3. The special arrangement of the rotary pistons and steam and exhaust ports
together with the elliptical toothed gearing substantially as set forth, whereby, in
an apparatus for converting fluid pressure into mechanical work or vice versa, each
piston in turn acts as a steam valve, and is in turn a slow and a quick travelling
piston with an alternate purchase one over the other.
4. The special construction of the variable speed elliptical gear wheels with their
teeth arranged radial to the axis of revolution, substantially as described with
reference to the accompanying drawings.

page_text: 5. The general arrangement or construction of parts forming the improved
apparatus for converting fluid pressure into mechanical work and vice versâ
substantially as and for the purposes described.
Dated this 2nd day of March 1893.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.