Improvements in Machinery or Apparatus for Fluid Compressing and Refrigerating Purposes.
Year: 1896

page_text: Improvements in Machinery or Apparatus for Fluid Compressing and
Refrigerating Purposes.
A communication from abroad by NORMAN SELFE, M.I.C.E., of George Street, Sydney,
in the Colony of New South Wales.
I, CHARLES JAMES BENNETT, Junior, of The Homestead, The Manor Way,
Blackheath, in the County of Kent, Gentleman, do hereby declare the nature of this
invention to be as follows:-
This invention has for its object to increase the efficiency of compressors such as
are used in the arts for artificial refrigeration or the supply of compressed air. One of
the improvements relates to the arrangement and design of the compressing cylinders
in combination with the steam engine supplying the motive power. As is well
known, the greatest work on a compressor piston occurs towards the latter end of the
stroke, where a steam engine working expansively is decreasing in power, hence it
is common to arrange steam engines and compressors on separate foundations, to
work on to, and from, separate cranks on the same shaft, such cranks being arranged
at a certain angle with one another; a similar effect can be, and is effected by
applying the power to, and taking it from, one crank only, by connecting rods working
at different angles, the engine and compressor being arranged diagonally. Now
according to this invention there are combined two vertical compressors with a
horizontal engine, and a three armed beam or lever with the necessary connecting
rods, arranged in such a way with a single crank, that the whole machine is simplified
by being complete on one sole plate or foundation, and the motion of the compressor
pistons is brought relatively in advance of the steam engine piston so as to bring the
inaximum power of the engine. to bear where the greater power for compression is
required.
Another part of the invention relates to, a novel construction of the compressor
oylinders and pistons in such a way as to produce compound compression. As above
stated, and as is well known, the greater strain on compressor pistons occurs at the
latter end of the stroke, and in single acting compressors this maximum strain occurs
only on one stroke, and thus only during a small portion of the whole circle of the
crank pin's path. The advantages of compressing by stages, in equalising the strains
on the machinery, and reducing liability to breakdowns are well known, and compound
compressors are already in use, but the multiplication of parts in an ordinary com-"
pressor is an objection to its general adoption, especially for small powers; according to
this invention there is produced a simple form of compound compressor, under which both
pistons may be worked by one and the same piston rod, and in which the cylinders
and pistons for the two stages of compression are combined in such a way with a
suction chamber, that there are no external pipes or connections between them, and
all leakage past the two pistons is retained in the enclosing chamber.
Another part of the invention relates to the construction of a single acting
compressor, the object being to enable the compressing cylinder or working barrel

page_text: proper to be made a separate casting of specially hard metal, while the necessary
ports or passages connected with such cylinder are arranged in a separate casting
forming the outer part, this improvement also allows certain holes or passages that
would otherwise have to be cored or drilled from the inside of the barrel, to be drilled
from the outside of same, and in other ways the improvements facilitate the practical
construction of the compressor.
The accompanying illustrative drawings and the following description will onable
this invention to be clearly understood the samo letters or characters, where used on
more than one figure, having reference to similar parts.
Fig. 1 shows a side elevation of two vertical compressors and a horizontal steam
engine on one foundation.
Fig. 2 shows an end elevation of the same.
Fig. 3 a ground plan.
Fig. 4 shews a compound compressor with the improvements, arranged to be
carried on the framing, and worked with such a machine as that shewn in Fig. 1.
Fig. 5 shows a single acting compressor with the improvements arranged to be
carried on the framing, and to be worked with such a machine as that shewn in
Fig. 1.
Fig. 6 shews a modification of the improved compound compressor, similar to
that illustrated by Fig. 4 but in this case having the pistons driven by two piston
rods.
Fig. 7 shows a modification of the improved compound compressor similar to that
illustrated by Fig. 4 but having the suction chamber enlarged so as to enclose the
crank and connecting rods, the crank shaft working through a stuffing box.
Fig. 8 shews a modification of the improved compound compressor,, shewing how
the high pressure cylinder can be connected to the low pressure piston and made
movable, the high pressure piston being fixed, and the whole enclosed in a casing in
the same way as in the arrangement shewn by Figs. 4 6 and 7.
Referring to Figures 1, 2, and 3.
A¹ A are the compressing cylinders, which may be double acting or single
acting, or both compound, or one high and the other low pressure.
BB are the rods giving motion to the pistons of such compressors.
CC are the crossheads on B¹ B¹¹.
D is a rocking beam, lever, or bell crank.
E is the main centre or fulcrum of rocking beam D.
E' is the end centre or gudgeon for working cylinder A¹
El is the end centre or gudgeon for working cylinder A".
E is the centre or gudgeon by which motion is transmitted to beam D from the
crank shaft.
F F are rods or links connecting crossheads C¹C" with gudgeons E¹ E¹¹.
G is a crank shaft.
His a long crank pin in the solid with crank shaft G.
JJ are connecting rods from the crank pin H to work the beam by
gudgeon E!!!
K is a horizontal steam engine cylinder or cylinders, simple or compound.
L the piston rod of the engine.
M the crosshead, and N the connecting rod of same, giving motion to crank pin H,
and rotation to shaft G.
O'is a flywheel, in either or both ends of crank shaft G.
P is an eccentric to operate slide or other valves of steam engine.
Qis a pulley to drive governor.
R the sole plate or foundation casting for the whole machine.
SS the main bearings for crank shaft G on sole plate R.
TT the alternative supports for cylinder K on sole plate R.
U U the guide bars for crosshead M.
Vivy v guide bars for crossheads C and C¹¹.
W W W holding down bolts for sole-plate R.

page_text: crank shaft by means of the steam engine in the usual manner, and connecting
rods J, J, cause the oscillation of the rocking beam, lever or bell crank from the
rotation of the same crank pin, without any tortional strain on the shaft, such as is
the case when tivo separate cranks are used for the engine and compressor at the
opposite ends of a shaft in the way more usually adopted. By means of the
connecting rods F, F, motion is imparted to the compressing pistons from the pins
or gudgeons in the rocking bean, and there is thus much less friction on the guides,
the crosshead pin, and the gudgeons, than would be caused if they were driven from
the crank pins and complete rotary motion, because the versed sine or arc of the
gudgeons motion, and angle of connecting rods, is so small as compared to the
diameter of crank pin circle for the saine stroke, the engine being drawn on the same
centre line as the compressors, a pair of links or connecting rods is shewn to the
three pairs of gudgeons forming the moving centres of the bell crank, and no side
wrench or uneven strains are produced in the working of the machine, but it is
evident that by putting the engine centre slightly to one side of the compressor
centres, the connecting rods F, F, and J, J, inight all be. inade single, and miss
the piston rod and connecting rod of the engine, and the machine would still be
without any torsion on the crank shaft. Owing to the angle at which the connecting
rods J, J, lie with regard to the connecting rod N. or centre line of the steam
engine, the steam piston is in about its most powerful position for action on the
crank when the compressor pistons are approaching the end of their stroke, and the
pressure against them is greater, the action of the crank on the connecting rods to
the beam is somewhat like that of a toggle joint, and the result is the exercise of
most pressure when required, securing more equable notion and requiring less
weight of fly wheel. There may be one or two fly wheels on the crank shaft, and
from the general design of the whole machine as drawn, with the beam below the
centre of engine, it is rendered practicable to simplify and reduce the cost of
foundations when desired, by keeping the fly wheels altogether above the floor line.
Although a simple steam cylinder is shewn, it is evident that a compound engine
could be applied, either with the cylinders tandem or side by side; in the latter case,
the compressor piston rods or connecting rods could pass between the steam piston
rods and connecting rods. It is also clear that the guides for the compressors could
be placed below the centre line of the steam engine without affecting the leading
features of the design, and that the third arm of the lever could be extended until
the connecting rod to the crank was vertical.
In the compound form of compressor shewn by Figs. 4, 6, and 7, the operation is
as follows. Motion being communicated to crosshead g, by either of the methods
shewn, or in any other obvious way, the two connected pistons are moved up and
down in their respective cylinders. The casing a, being in connection with a supply
of the fluid to be compressed, an up stroke draws in from it a supply through the
lower suction valve j, and upon the piston c passing the small openings p, p,
equilibrium is established between the cylinder and the casing, notwithstanding the
pressure of the springs on valve j. On the down stroke, the contents of b; are
compressed, passing through valves k, and m, through passage f¹, to cylinder d; and
on the succeeding up stroke, the material is further compressed and expelled by
valve n, through exit passage o. Should the pistons c, or e, be a loose fit in their
cylinders, and pass gas or air, the saine is retained in chamber a, and re-pumped
through j, or p, p. Owing to the upper end of b, and lower end of d, being open to a,
and the piston c, being larger than piston e, the capacity of a, is enlarged during the
down stroke by the difference of the displacement of the two pistons, and a partial
supply is drawn in through inlet h., On the upstroke, when b, is being filled from a,
through j, the capacity of d, is being reduced by the difference of the displacement
of the two pistons, and supplies a portion of the volume drawn into b, the balance
required to supply it being drawn in through h. In this way the chamber a, acts
the part of an equaliser, and there is a double acting suction through h, during both
up and down strokes, materially reducing the friction on the pipes supplying the
dompressor. As the whole ratio of compression is divided between the two cylinders,

page_text: each piston, if correctly proportioned, will do one half of the whole work, instead of
the whole work being performed by the up stroke alone, as in ordinary compressors,
and as the ratio of compression in each cylinder is much smaller than it would be in
one, delivery will be earlier in the stroke, because the ratio of compression being less,
the pressure for expulsion is reached earlier, and thus the work is divided over a
greater proportion of both the up and the down strokes, instead of being performed
by a lesser proportion of one stroke ouly; less strength is therefore required in the
parts, and a more uniform power is required to be applied to the circular travel of
the crank shaft, ensuring smoother working and less wear and tear, which is specially
severe in ordinary single acting compressors. It is evident that a layer of oil may
cover the bottom of chamber a, to seal the rods where passing through the stuffing
boxes in Fig. 4 or 6, or the crank shaft itself in Figure 7, inay work in oil, without
carrying the oil directly into the cylindera. In Figure 8 a modification is shewn,
under which the combined compound cylinders, pistons, and chamber occupy
somewhat less vertical space than the arrangements in Figs. 4, 6, and 7, require for
the same length of stroke, the chief difference being a fixed piston and moving
cylinder for the second compressor, instead of fixed cylinder and moving piston,
otherwise the figure explains itself.
In Figure 5, the special construction of the cylinder described enables the main
casting to be made without any cored ports or passages to form the chamber, and the
branches thereto, and the openings 11 to be drilled instead of being cored. The
flanges 5 and 15 being kept apart, instead of being combined as is usually the case,
enables the cylinder to be all bolted up complete and the joints made before erection.
By the simplicity of casting 1, it inay easily be made of a hard material such as
hematite, that would be difficult with cored ports or passages. When the piston is
on the down stroke, gas or air is drawn through valve 8 to the space above the piston,
and at the bottom of the stroke, the openings 11, being uncovered, equilibrium is
established on both sides of the piston, and with 7 allowing the cylinder to be charged
with the full suction pressure. On the up stroke, the contents of the cylinder are
expelled through 9 or 91 and 10. The upper part of the cylinder being subjected to
the heat of compression, the water jacket 14 enables it to be kept cool. It is obvious
that many devices are shewn which are. common to compressors, and therefore
separately form no part of the invention, at the same time, it is evident that many
ninor modifications could be made in the parts without affecting the invention.
In Fig. 8, the operation performed is practically the same as that described for
Figs. 4, 6, and 7, but cross-head y, is connected to, and moves cylinder d; while
piston e, is stationary, and chamber or passage f is through the interior of piston. c.
Dated this 20th divi of Desamber 1906
Improvements in Machinery or Apparatus for Fluid Compressing ana
Refrigerating Purposes.
15 A Communication from abroad by NORMAN SELFE, M.I.S.E., of Sydney, in the Colony
of New South Wales.
I, CHARLES JAMES BENNETT, Junior, of The Homestead, The Manor Way,
Blackheath, in the County of Kent, Gentleman, do hereby declare the nature of this

page_text: invention 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 to increase the efficiency of compressors such as
are used in the arts for artificial refrigeration or the supply of compressed air. One
of the improvements relates to the arrangement and design of the compressing
cylinders in combination with the steam engine supplying the motive power. As is
well known, the greatest work on a compressor piston occurs towards the latter end
of the stroke, where a steam engine working expansively is decreasing in power.
Hence it is common to arrange steam engines and compressors on separate
foundations, to work on to, and from, separate cranks on the same shaft, such cranks
being arranged at a certain angle with one another; a similar effect can be, and is
effected by applying the power to, and taking it from; one crank only, by connecting
rods working at different angles, the engine and compressor being arranged
diagonally.
Now according to this invention there are combined two vertical compressors with
a horizontal engine, and a three armed beam or lever with the necessary connecting
rods, arranged in such a way with a single crank, that the whole machine is simplified
by being complete on one sole plate or foundation, and the motion of the compressor
.pistons is brought relatively in advance of the steam engine piston so as to bring
the maximum power of the engine to bear where the greater power for compression
is required:
Another part of the invention relates to a novel construction of the compressor
cylinders and pistons in such a way as to produce compound compression. As above
stated, and as is well known, the greater strain on coinpressor pistons occurs at the
latter end of the stroke, and in single acting compressors this maximum strain
occurs only on one stroke, and thus only during a small portion of the whole circle
of the crank pin's path. The advantages of compressing by stages, in equalising the
strains on the machinery, and reducing liability to breakdowns are well known, and
compound compressors are already in use, but the multiplication of parts in an
ordinary compressor is an objection to its general adoption, especially for small
powers; according to this invention there is produced a simple form of compound
compressor, under which both pistons may be worked by one and the same piston
rod, and in which the cylinders and pistons for the two stages of compression are
combined in such a way with a suction chamber, that there are no external pipes or
connections between them, and all leakage past. the two pistons is retained in the
enclosing chamber.
Another part of the invention relates to the construction of a single acting.
compressor, the object being to enable the compressing cylinder or working barrel
proper to be made a separate casting of specially hard metal, while the necessary
ports or passages connected with such cylinder are arranged in a separate casting
forming the outer part, this improvement also allows certain holes or passages that
would otherwise have to, be cored or drilled from the inside of the barrel, to be
drilled from the outside of same, and in other ways the improvements facilitate the
practical construction of the compressor.
The illustrative drawings left with my Provisional Specification and the following
description will enable this invention to be clearly understood, the same letters or
characters, where used on more than one figure, having reference to similar parts.
Fig. 1 shows a side elevation of two vertical compressors and a horizontal steam
engine on one foundation;
Fig. 2 an end elevation; and Fig. 3 a ground plan of the same;
Referring to these figures A¹ All are the compressing cylinders, which may be
double acting or single acting, or both compound, or one high and the other low
pressure, B B are the rods giving motion to the pistons of such compressors, and
CC are the cross heads on B. B. D is a rocking beam, lever, or bell crank of
which E is the main centre or fulcrum, E¹ the end centre or gudgeon for working the
'cylinder A', E¹¹ the end centre or gudgeon for working cylinder A", and Ell the

page_text: centre or gudgeon by which motion is transmitted to the beam D from the crank
shaft. FF are rods or links connecting the cross heads C C with the
gudgeons E E. G is the crank shaft, H being a long crank pin made solid' with
crank shaft G. J1 J1 are connecting rods from the crank pin II to work the beam
by gudgeon E K is a horizontal steam engine cylinder, and L its piston rod,
M the cross head, N the connecting rod of same, giving motion to crank pin H, and
rotation to shaft. G, and O the flywheel: P is an eccentric to operate the slide or
other valves of the steam engine and Q a pulley to drive governor. R is the sole
plate or foundation casting for the whole machine, formed with main bearings St, Su,
for the crank shaft G and alternative supports T T for cylinder K. U U are the
guide bars for crosshead M and V, V, V, V, those for the crossbeads Ci C.
WWW are holding down bolts for sole-plate R and X X are column or standard
castings bolted to the sole plate R to carry cylinders A1 A¹¹.
Rotation is given to the crank shaft by means of the steam engine in the usual
manner, and the connecting rods JJ cause the oscillation of the rocking beam,
lever or bell orank from the rotation of the same crank pin without any tortional
strain on the shaft, such as is the case when two separate cranks are used for the
engine and compressor at the opposite ends of a shaft in the way more usually adopted.
By means of the connecting rods F1 F1, motion is imparted to the compressing pistons
from the pins or gudgeons in the rocking beam, and there is thus much less friction
on the guides, the crosshead pins, and the gudgeons, than would be caused if they
were driven from rotating crank pins because the versed sine or are of the motion of
the gudgeons and the angle of connecting the rods, is so small as compared to the
diameter of a crank pin circle or path for the same stroke. The engine being on the
same centre line as the compressors, a pair of links or connecting rods is employed,
as shewn, in connection with each of the three pairs of gudgeons forming the moving
centres of the bell crank, and no side wrench or uneven strains are produced in the
working of the machine, but it is evident that by putting the engine centre slightly
to one side of the compressor centres, the connecting rods F F and JJ11 might all
be made single, and miss the piston rod and connecting rod of the engine, and the
machine would still be without any torsion on the crank shaft. Owing to the anglo
at which the connecting rods J1 Julie with regard to the connecting rod N or centre
line of the steam engine, the steam piston is in about its most powerful position for
action on the crank when the compressor pistons are approaching the end of their
stroke, and the pressure against them is greater; the action of the crank on the
connecting rods to the rocking-beam is somewhat like that of a toggle joint, and the
result is the exercise of most pressure when required, securing more equable motion
and requiring less weight of fly wheel. There may be one or two fly wheels on the
crank shaft, and from the general design of the whole machine as drawn, with the beam
below the centre of engine, it is rendered practicable to simplify and reduce the
cost of foundations when desired, by keeping the fly wheels altogether above the
floor line. Although a simple steam cylinder is shewn, it is evident that a compound
engine could be applied, either with the cylinders tandem or side by side; in the
latter case, the compressor piston rods or connecting rods could pass between
the steam piston rods and connecting rods. It is also clear that the guides for the
compressors could be placed below the centre line of the steam engine without
affecting the leading features of the design, and that the third nrm of the lever could
be extended until the connecting rod to the crank was vertical.
Fig. 4 shows a compound compressor according to this invention and arranged to
be carried on the framing of and worked with a machine such as that with reference
to Figs. 1 2 and 3.
Fig: 5 shows a single acting compressor according to this invention hereinafter
more particularly described which is arranged to be carried on the framing of and to.
be worked with a machine such as that described with reference to Figs. 1 2 and 3.
Fig. 6 shows a modification of the improved compound compressor, similar to
hat illustrated by Fig. 4 but in this case having the pistons driven by two piston
ods,

page_text: Fig. 7 show a modification of the improved compound compressor similar to that
illustrated by Fig. 4 but having the suction chamber enlarged so as to enclose the
crank and connecting rods, the crank shaft working through a stuffing box.
Fig. 8 shews a modification of the improved compound compressor, shewing how
the high pressure cylinder can be connected to the lower pressure piston and made
movable, the high pressure piston being fixed, and the whole enclosed in a casing in
the same way as in the arrangement shewn by Figs. 4 6 and 7.
Referring to Figures 4, 6, 7, and 8.
a is an air or gas tight casing with a stuffing box or boxes adapted to retain the
fluid to be compressed. bis the low pressure cylinder for the first stage of compres
Bion, and the low pressure piston. d is the high pressure cylinder and e the high
pressure piston. is a trunk that connects the two pistons c and e and is forined
with a central channel or passage fl, and with a crosshead g by which the pistons
receive their notion in the cylinders. h is the inlet or suction branch for
admitting the fluid to be compressed-to the chamber a; it may be provided with a
stop valve.
jis the inlet valve from the casing a to the cylinder b, and k is the delivery valve
from the cylinder b into the channel f m is the inlet valve to the high pressure
cylinder from passage f1, n the delivery valve of the high pressure cylinder d, and o the
delivery or pressure branch for the compressed fluid. pp are small openings in the
walls of the cylinder b, uncovered by the piston c, when at the top of its stroke, and
60 establishing direct communication between the casing a and the cylinder b.
In Figure 5, 1 is the barrel or working cylinder of a single acting compressor, 2 the
piston with valve opening upwards, and 3 the cylinder bottom provided with a stuffing
box 4 for the piston rod. 5 is a joint or flange-connection between the barrel 1 and
the cylinder bottom 3, at some distance above the bottom of the cylinder and clear
of the foundation flange. 6 is a chamber or casing surrounding the bottom of the
barrel 1 below the flange-connection 5. 7 is the inlet or suction branch in direct
communication with the chamber 6, 8 a valve in piston 2, 9 the maiu delivery valve
with a smaller valve 9' in the centre, and 10 is the outlet or delivery branch.
11, 11 are openings, establishing direct communication between the chamber 6 and
the interior of cylinder 1, when they are not covered by the piston. 12 is a clear
space opening from chamber 6 into bottom of cylinder 1. 13, 13 are fitting strips to
ensure concentricity between the barrel and the piston with the cylinder end and the
stuffing box.
14 is a water casing surrounding the upper part of barrel 1 above the
flange 5, and 15 is the foundation flange, by which the compressor, is carried on its
support. is a column or support as shown on Figs. 1, 2 and 3.
The special construction of the cylinder described enables the main casting to be
made without any cored ports or passages to form the chamber and the branches
thereto, and the openings 11 to be drilled instead of being cored. The flanges 5 and 15
being kept apart, instead of being combined as is usually the case, enables the cylinder
to be bolted up complete and the joints made before erection. By the simplicity of
the casting 1, it may easily be made of a hard metal such as hematite iron, which
would be difficult if the ports or passages were cored. When the piston is on the
down stroke, gas or air is drawn through valve 8 to the space above the piston, and
at the bottom of the stroke, the openings 11, being uncovered, equilibrium is
established between the two sides of the piston and the inlet or suction 7, allowing
the cylinder to be charged with the full suction pressure. On the up stroke, the
contents of the cylinder are expelled through 9 or 91 and 10. The upper part of the
cylinder being subjected to the heat of compression, the water jacket 14 enables it to
be kept cool. It is obvious that many devices are shown which are common to
compressors, and therefore separately form no part of the invention, at the same
time, it is evident that many minor modifications could be made in the parts without
affecting the invention.
In Figure 49 are side rods, a crosshead inside the casing a and aa rod working
through a stuffing box, by which motion is communicated from the outside to the
pistons c and e. X corresponds to the upper part of column X' in Figs. 1, 2 and 3,

page_text: In Figure 6, 9 9 are side rods secured to r, outside a, working through separate
stuffing boxes, by which motion is communicated from the outside to pistons c and e.
In Figure 7, within the casing a are arranged connecting rods q, q that oscillate on
the cross-head g, and a crank shaft t, that works through a stuffing box u and by which
motion is communicated from the outside to the pistons c andie.
Other parts, the use of which is obvious, or which do not affect the invention, need
not be described.
In the compound form of compressor shown by Figa. 4, 6, and 7, the operation is
as follows:-Motion being communicated to crosshead g, by either of the methods
shewn, or in any other obvious way, the 'two connected pistons are moved up and
down in their respective cylinders. The casing a, being in connection with a supply
of the fluid to be compressed, an up stroke draws in from it a supply through the lower
suction valve j and, upon the pistou e passing the small openings p, p equilibrium is
established between the cylinder and the casing, notwithstanding the pressure of the
springs on valve j. On the down stroke, the contents of the cylinder b are
compressed, passing through the valves and m, through the passage f to the
cylinder d; and on the succeeding up stroke, the fluid is further compressed and
expelled by way of the valve n through the exit passage o. Should either the pistons
core be a loose fit in their respective cylinders and pass gas or air, the same is
retained in the casing a, and re-pumped through j, or p p. Owing to the upper end
of the cylinder b and the lower end of the cylinder d being open to a and the piston c
being larger than the piston e the capacity of the casing a is enlarged during the
down stroke by the difference of the displacement of the two pistons, and a partial
supply is drawn in through the inlet h. On the upstroke, when the cylinder b is being
filled from the casing a, through the valvej, the capacity of the casing a is being
reduced by the difference of the displacement of the two pistons, and supplies a portion
of the volume drawn into the cylinder b, the balance required to supply it being
drawn in through the inlet h. In this way the chamber a acts the part of an
equaliser, and there is a double acting suction through the inlet h, during both up
and down strokes, materially reducing the friction on the pipes supplying the
compressor. As the whole ratio of compression is divided between the two cylinders,
each piston, if correctly proportioned, will do one half of the whole work, instead of
the whole work being performed by the up stroke alone, as in ordinary compressors,
and as the ratio of compression in each cylinder is much smaller than it would be in
one, delivery will be earlier in the stroke, because the ratio of compression being leas,
the pressure for expulsion is reached earlier, and thus the work is divided over a
greater proportion of both the up and the down strokes, instead of being performed
by a lesser proportion of one stroke only; less strength is therefore required in the
parts, and a more uniform power is required to be applied to the circular travel of the
crank shaft, ensuring smoother working and less wear and tear, which is specially
severe in ordinary single acting compressors.
It is evident that a layer of oil may cover the bottom of chamber a, to seal the rods
where passing through the stuffing boxes in Fig. 4 or 6, or the crank shaft itself in
Figure 7, may work in oil, without carrying the oil directly into the cylinders.
In Figure 8 a modification is shewn, under which the combined compound
cylinders, pistons, and casing or chamber occupy somewhat less vertical space than
the arrangements shown in Figs. 4, 6 and 7 require for the same length of stroke, the
chief difference being a fixed piston and moving cylinder for the second compressor,
instead of fixed cylinder and moving piston, otherwise the figure explains itself.
The operation performed is practically the same as that described for Figs. 4, 6, and 7,
but the cross-head g is connected to and moves the cylinder d; while the piston e is
stationary, and the chamber or passage fi is through the interior of piston c.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Machinery or apparatus for fluid compressing and refrigerating purposes con-

page_text: structed and operating substantially as described with reference to Figs. 1, 2 and 3 of
the drawings.
2. In machinery or apparatus for fluid compressing and refrigerating purposes; the
combination on one sole plate or foundation for the purposes set forth of two vertically
acting compressors, an horizontal engine, à crank shaft with a single crank, and a
rocking beam or lever with 'the necessary connecting rods, guides, and appurtenances
substantially as described with reference to and shown in Figs. 1, 2, and 3 of the
drawings.
3. In machinery or apparatus for fluid compressing and refrigerating purposes, the
combination of two single acting. compressing cylinders having their pistons con-
nected by a trunk (or having a passage through the piston or pistons from one
cylinder to the other) with a chamber, the arrangement being such that leakage past
the pistons is retained in. the chamber so as to be again drawn into the compressing
cylinders, substantially as described with reference to and shewn in Figures 4, 6, 7,
and 8 of the drawings.
4. In machinery or apparatus for fluid compressing and refrigerating' purposes 'the
combination of two single acting compressing cylinders with a suction chamber, the
arrangement being such that the two pistons (or a piston and cylinder) may have
motion imparted to them through connections arranged within such chamber, the
part or parts. which is or are extended to the exterior of the chamber for connection
with the source of motion being suitably packed to maintain the, chamber air tiglit
substantially as described with reference to and shewn in Figures 4, 6, 7, and 8 of the
drawings.
5. In machinery or apparatus for fluid compressing and refrigerating purposes, con-
structing the working barrel of a single acting compressor with a separate casting
adapted to forin an annular chamber surrounding the barrel and communicating
therewith by openings such as the openings 11 and 12 (Fig. 5), substantially ans
described with reference to and shown in the drawings.
Dated this 20th day of September 10.
For the Applicant,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.