IMPROVEMENTS IN MACHINERY FOR COM- PRESSING AIR OR OTHER GASEOUS FLUID
Year: 1885

page_text: Gaseous Fluid.
I ALEXANDER BASIL WILSON of Holywood Belfast, Ireland, Engineer do hereby
declare the nature of my invention for IMPROVEMENTS IN MACHINERY FOR COM-
PRESSING AIR OR OTHER GASEOUS FLUID and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:
This invention has for its object the improvement of the general arrangement of
cylinder pumps and valve gear of combined steam engines and air or other fluid
compressing pumps. So that the best effect may be obtained from the steam,
the number of working parts reduced, those parts subjected to the smallest wear
and strain and a steady and uniform motion obtained at different speeds.
For this purpose I use three double acting steam cylinders as commonly adopted
in triple Expansion Engines, and to the piston-rod of each I couple direct one
piston of a single acting air compressing pump, and through the intervention of a
lever and links I couple a second similar piston, so arranging them that they
balance each other and enter and leave their respective cylinders alternately ;--and
I further connect the ends of the above mentioned main levers opposite to those
connected to the Steam Cylinders by connecting rods, as usual in beam Engines to
a crank shaft having three cranks set at angles of 120° to each other.
Each machine consists therefore of three Steam Cylinders six air Cylinders and
their various connections. And I unite them in such a manner that the central
axis of the main levers are in one line and the connecting rods work on separate
cranks forming one crank shaft on which Fly wheel or wheels may be placed if
required. From the Main levers as above described I obtain by rods shafting and
link gear or other well known device the motion required for the Steam Engine
valves.
By a machine thus constructed I obtain the following advantages.
By using a triple Expansion Engine as described above each cylinder of which is
coupled direct and by lever to its own pair of compressing pumps I obtain &
steady motion, all the parts being easily balanced. Great economy of steam. Few'
working parts with direct and unusually uniform strain on them, the power of each
steam Cylinder being for the most part absorbed by its own pair of Compressors

page_text: there is consequently comparatively little strain thrown on the crank shaft and
I can therefore make it smaller and reduce or do away with Fly wheels
altogether.
By working the Steam valves from the main levers I reduce working parts and
avoid the irregularity in the steam admissions to the Cylinders consequent to the
length of connecting rod to which all Engines which have their valves worked by
Eccentrics or by other means from the crank shaft are subject.
The following is a description with reference to the accompanying drawing of a
way by which my invention may be conveniently carried out in practice.
Figures 1 and 2 are front and side elevations of a set of three steam cylinder air
compressing Engines, arranged according to my invention.
A₁ A, A, are the High, Middle, and Low pressure Steam Cylinders. B₁ B₂ B, are
the Air Compressing Cylinders, or pumps, b₁ being one of those over the centre of
crank shaft C, C₂ C, of which the cranks correspond to their respective Cylinders,
in the same manner as D, D₂ Ds, the levers; E, E, E, the valve spindle of Steam
Cylinders; F, F, F, the Rocking shafts; G, G, Gs, the coupling rods; 91 92 93, the
coupling levers; H, H, H, and h₁ h₂ h, the valve levers; K₁ K, K, and k₁ ką ks the
valve rods; L, L, L, the valve quadrants, the positions of which are regulated by
governor levers, M, M, M, controlled by a governor or by hand as may be found
suitable.
In this arrangement, to prevent the valve motion being a reversing gear, and to
constitute it an expansion gear, the valve quadrants are specially constructed and
connected to the governor levers so that the distance between X and x. is not
greater than between Y. and y. and the position of the quadrant between the
points Y. and y. determines the amount of steam admitted by the valves into the
steam cylinders, the maximum amount being given when the valve rods are over
the centres of the valve spindles, the minimum when the centres of valve spindle
are equidistant between the rods.
I also, if required connect one set of the valve rods such as K, K, K, direct to
the slide valve spindles E, E, E, by a joint at e, e, e, and the other rods k₁ kg kg to
a series of expansion valves one on each steam cylinder whose stroke is regulated
by quadrants similar to L, L, L, or other usual means. Or, I may also actuate the
Slide valves by rods direct from levers H₁ H, H, and regulate the varying
admission of steam to the cylinders by any well known motion derived from that
of the Crank Shaft.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
In machines for compressing air or other Gaseous fluid where a Steam Engine
and pressing pump are combined the use of triple expansion Engines having steam
valve gear actuated by the motion of the main levers substantially as described.
GEO. DOWNING,
Agent for Applicant.