IMPROVEMENTS IN MACHINERY FOR OB- TAINING MOTIVE POWEB, APPLICABLE ALSO TO MEASURING, RAISING, EXHAUSTING, FORCING, AND COMPRESSING FLUIDS
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Alfred Colerick Pilliner and
James Charles Hill at the Office of the Commissioners of Patents,
with their Petition, on the 24th December 1868.
We, ALFRED COLERICK PILLINER, of the Oakfield Works, near
Newport, in the County of Monmouth, Civil Engineer, and JAMES
CHARLES HILL, of the same Place, Ironmaster, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN MACHINERY FOR OB-
TAINING MOTIVE POWEB, APPLICABLE ALSO TO MEASURING, RAISING, EXHAUSTING,
FORCING, AND COMPRESSING FLUIDS," to be as follows:-
This Invention applies to rotary engines in which spur or toothed
wheels gearing together are enclosed in a case, against the interior of
which the teeth (or some of them) as the wheels revolve work steam-
tight, except where the teeth interlock, and here in such engines the
teeth by bearing the one against the other form a steam-tight partition,
on one side of which is the inlet for the steam or fluid, and on the
other the outlet; then the fluid if under pressure rotates the wheels
in forcing its way to the outlet, and the action is similar when the

page_text: fluid is not under pressure and the wheels are driven by other means.
When such engines are intended to be driven by steam or other elastic
fluid it is desirable that the fluid should be expanded in the engine
and that the degree of expansion should be capable of variation from
time to time. We attain this object by mounting one of the wheels on
a stationary axle which is hollow and has the fluid admitted to its
interior; a number of slots or ports are formed in the axle, which
however are closed fluid-tight by the wheel fitting truly on to the axle,
except that there are certain passages formed in the wheel, which as
the wheel revolves pass over the slots or ports in the axle and so allow
the issue of the fluid; we usually employ wheels having eight teeth,
but with only every alternate tooth adapted to make a tight joint with
the casing; in this arrangement there will be four passages in the wheel
one for each quadrant of the wheel, and the passages lead through
the wheel into the spaces between the teeth. Now if the action of the
wheels as they rotate be observed it will be found that as each pair of joint-
making teeth passes the line where the teeth are in contact, when they
meet the casing they enclose a space, the capacity of which continues
to increase as the wheels revolve until the next pair of joint-making
teeth come round in a similar manner. It is to this space that the fluid
is admitted. The slots and passages are so arranged that the fluid
commences to pass as soon as the space is enclosed by the teeth meeting
the casing, and so that it may if desired continue to flow in until
the space attains its full capacity. When the engine is to work
expansively however the flow is stopped at an earlier period, and this
is done by covering some of the slots or ports in the hollow axle,
which contains for this purpose a plug with an opening on one side;
this plug can be turned round within the hollow axle, and so made
to cover any of the slots or ports which it may be desired to close;
thus if desired all the slots or ports but the first may be covered, and
then the fluid will be admitted only when the space in which it acts
is at its minimum capacity; in this case the engine will be working
at its greatest expansion. By the same means the engine may be
stopped by placing the plug so as to cover all the slots or ports. To
reverse the engine the plug is turned still further round, and then it
opens slots or ports formed on the opposite side of the hollow axle
and at the same time it serves as a cock to open a new outlet passage
and close that, which had previously been used.

page_text: In order to the proper working of engines of this description it is
essential that the joint-making teeth of the two wheels should come
into action simultaneously, that is to say, that of each pair acting
together to enclose a fluid space one should not make a close joint
with the casing before the other; to prevent this we form passages in
the casing which allow the fluid to pass the leading tooth until the
other comes into contact with the casing. Also in order to protect the
top of the effect that would arise from two pairs of the teeth making
a fluid-tight joint at the same time, and thus from their angular position
widening the area of resistance and locking in a portion of the fluid,
we cut grooves or passages in the teeth either above or below the
pitch line at a certain distance from it, so that the fluid-tight joint shall
depend on the contact of one pair of teeth only in gear at the same time.
The same object may be attained by the arrangement of the passages
in the cover. We usually construct the engine so as to be double-
acting, that is to say, we employ three gearing wheels admitting the
fluid through the axles of the two outer wheels and driving from or
by the axis of the central wheel. We do not key this axis into the
wheel, but pass it loosely through the wheel and clutch it thereto.
The inner end of the axis works on a centre pin within the casing.
This arrangement renders the proper working of engines independent
of absolute truth in the mounting of the driving axis in its outer
bearing.