IMPROVE- MENTS IN MEANS OR APPARATUS FOR OBTAINING MOTIVE POWER
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Benjamin Joseph Barnard Mills at
the Office of the Commissioners of Patents on the 14th November 1878.
A communication from abroad by Jules Gfeller, Usine de Mauremont, Eclépens,
Canton of Vaud, Switzerland.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent. " IMPROVE-
MENTS IN MEANS OR APPARATUS FOR OBTAINING MOTIVE POWER." A communi-
cation from abroad by Jules Gfeller, Usine du Mauremont, Eclépens, Canton of
Vaud, Switzerland.
The Invention has for its object improvements in means or apparatus for
obtaining motive power.
For this purpose an outer case or cylinder is employed having an inlet port at
one end and an outlet port at the other end thereof.
Within this outer cylinder is an inner cylinder having flanges at its ends to
revolve in contact with the outer cylinder, and prevent the passage of steam
between the inner and the outer cylinders, suitable inlet and outlet ports being
arranged at each end of such inner cylinder. A steam space is left at one end
between the end of the inner cylinder and the outer cylinder, and a larger space
for the exhaust at the other end thereof. A shaft passing through the inner
cylinder and connected rigidly thereto passes through stuffing boxes on each end of
the outer cylinder. Around this shaft on the interior of the inuer cylinder is
wound a screw thread, which is made steam tight with the periphery of the inner
cylinder and with the shaft, to both of which it is fixed rigidly and with which it
revolves. The pitch of this screw thread increases from the inlet to the outlet port,
that is to say, the threads are comparatively close together at the inlet port, and
gradually increase in distance apart to the outlet port to form a proportionately
larger space to allow for the expansion of the steam or other fluid.
Or the screw thread may be wound around a cone carried by the shaft, and the
pitch of such screw may increase from the base of such cone towards the apex
thereof, the inner cylinder being made of a conical form to fit such screw thread.
In some cases a volute is employed in the interior of the inner cylinder in lieu of
ID 377

page_text: the screw, in which case the leaves of the volute are coiled around the shaft and
are attached rigidly thereto; the edges of the coils forming the volute being
attached rigidly to and made steam tight with the ends of the inner cylinder, and
the coils of this volute gradually approach nearer to each other from the shaft
outwards. The steam enters at the periphery of the inner cylinder and outermost
coil of the volute and exhausts at the centre thereof.
In the case of the volute form of engine and of the cone shaped form, the threads
or leaves of the screw or of the volute may instead of decreasing in pitch or
diameter from the shaft outwards, or from the base of the cone to the apex thereof,
sometimes increase in pitch or diameter, the steam always being arranged to enter
at the narrowest groove, and exhaust at the largest groove formed by the screw
threads or by the leaves of the volute.
The operation of the engine is as follows:-Steam is introduced at the narrowest
point of the groove formed by the screw or volute, and advancing with decreasing
speed expands towards the centre, where it escapes by the largest thread or groove..
The pressure of the steam is thus exerted against the walls or threads of the screw
or volute with a sufficient power of adhesion and propulsion to completely utilize all
the working power of steam.