Improvements in Refrigerating Machines.
Year: 1899

page_text: Date of Application, 12th Jan., 1899-Accepted, 25th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in Refrigerating Machines.
We, FREDERICK WILLIAM TANNETT-WALKER, of Hunslet, Leeds, in the County
of York, Engineer, and DANIEL MCGILL, of Hutt Road, Petone, Wellington, New
Zealand, Engineer, 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:―
This invention relates to machines in which air (or other gas) is compressed
and cooled and then expanded whilst doing work.
According to this invention the work of the power cylinders and of the air
expansion cylinder are utilized and more uniformly applied for effecting the work
of compression by means provided for storing power, the arrangement being such
that gas is compressed in the compression cylinder during the return stroke of
the power cylinder by means of the expansion of gas in the expansion cylinder
aided by the stored power.
In refrigerating machines also as usually constructed the suction and exhaust
valves through which the air is admitted into the compression cylinder and
expelled from it into the compressed air reservoir are spring loaded valves the
result being that during the suction the pressure in the cylinder is less than
that of the atmosphere whilst during the delivery the pressure in the cylinder is
greater than that in the reservoir.
According to this invention we obviate the losses resulting from such arrange-
ments by opening and closing the valves at the proper times not by the air pressure
but positively by some moving part of the machinery.
In order also to avoid loss of cold between the expansion cylinder and the
storage chamber we mix the expanded and extremely cold air from that cylinder
with the moderately cold incoming air from the compressed air cooler or from
the storage chamber or from both.
The arrangement we employ is as follows:-
The compression and expansion cylinders are single acting and are mounted in a
line with each other their piston rods being fixed to a crosshead between them.
The motive power is applied to the crosshead by a single acting steam or other
cylinder or a pair of single acting cylinders one high and one low one on each side
of the compression cylinder and working together or in the case of gas
engines giving only one impulse for each two revolutions the cylinders work
alternately.
On one side and preferably on each side of the expansion cylinder is a hydraulic
cylinder always in connection with an accumulator and having its piston rod or
ram fixed to the crosshead.
During the outstroke of the power cylinder air is drawn into the compression
cylinder, expanded and cooled air passes from one side to the other of the piston
of the expansion cylinder and water is forced into the accumulator. The return
stroke is performed by the expansion of compressed and cooled air in the expansion
cylinder and by the pressure of the water in the accumulator acting on the pistons
of the hydraulic cylinders. During the return stroke air is compressed in the

page_text: compression cylinder (and towards the end of the stroke expelled into the usual
cooling and drying apparatus) and expanded air is expelled from the expansion
cylinder
The compressed air coming from the cooling and drying apparatus enters the
expansion cylinder through a hollow casing or jacket surrounding it so that the
incoming air is partially cooled by the cold walls of the cylinder and the loss of cold
by conduction is considerably diminished. The expanded and extremely cold air
issuing from the expansion cylinder is mixed with moderately cold air drawn from
the refrigerating chamber and the mixture is led back to the refrigerating chamber.
By this means the great loss of cold which results from leading the extremely cold
air through the connecting pipes is considerably diminished.
We prefer to do this by making the expansion cylinder larger than is usual and
with an earlier cut off, the formation of a partial vacuum towards the end of the
stroke being prevented by opening a communication with the refrigerating
chamber from which moderately cold air is therefore now pumped. During the
return stroke the mixture of extremely cold air and moderately cold air is
expelled back into the refrigerating chamber.
The delivery valve from the compression cylinder and the admission valves to
the expansion cylinder are lift valves or it may be rotary disc valves in the cylinder
covers. These valves are worked by suitable gearing from a lay shaft and when
gas engines are employed this may conveniently be the valve shaft of the
engine.
The suction valves to the compression cylinder and the exhaust valve from
the expansion cylinder are similar lift or disc valves in the pistons. These
valves are worked by either sleeves on the piston rods or rods pass along inside the
piston rods and the ends of these sleeves or rods are connected by suitable gearing
to a rocking shaft in the crosshead whose ends are fixed to connecting rods working
on cranks on the fly wheel shaft.
Figure 1 is a diagrammatic plan of a refrigerating plant arranged according to
this invention. Figure 2 is a sectional plan of the engines and pumps and Figure 3
is a vertical section on the line 3-3 Figure 2.
Figures 4, 5 and 6 are local sections on the lines 4-4, 5-5 and 6-6 Figures 1
and 2 most of the parts behind the planes of section being omitted. Figures
and 8 are an elevation and plan to a larger scale of the gear working the admission
valves to the expansion cylinder.
a a are the cylinders of two single acting gas engines of the Otto type each giving
an explosion at every other out (or left to right) stroke of their pistons and arranged
to act alternately. a¹a¹ are their piston rods and a² a² the shafts working their
valves. One of these shafts is driven in the ordinary way from the crank shaft
and drives the other by bevel gear and a cross shaft a". As these engines are of an
ordinary and very well known type it is unnecessary to show or describe them in
detail.
b is the compression cylinder. e the expansion cylinder. 6¹ c¹ their piston rods
and 622 their pistons. d are hydraulic cylinders and d¹ their rams, the right hand
ends of these cylinders are always in communication by pipes & with an
accumulator e (Figure 1).
The rods a b c d are all fixed to a crosshead f which is connected by rods f¹
to cranks g on the crank shaft g on which is the flywheel g².
The crosshead f has fixed to it bearings in which works a rocking shaft f³.
f is an arm fixed to the shaft f2 and connected by a link f4 to one of the connecting
rods f. f is a double arm fixed to the shaft and connected by links fo f
to sleeves 33. free to move to and fro on the piston rods b¹¹ of the compression
and expansion cylinders.
These sleeves carry arms or discs bc which at the proper times come against
the stems of the valves b c in the pistons 622 and compressing the springs bec
open the valves.
By placing the valves in the pistons and operating them as above described

page_text: several important advantages_are_gained: The clearance_spaces-are-reduced-to-
a minimum, the valves can be quickly and widely opened at exactly the proper
times, and the valves being positively opened and not by the pressure of the air
as is usual do not act as reducing valves the pressure on both sides of them when
open being the same. It will be obvious that the movement of the connecting
rod can be communicated to the valves in various ways, thus the rod f¹ and shaft f
might be connected by bevel or other gear instead of by a link. The valves also
might rotate instead of lifting having radial ports (there being corresponding
ports in the pistons) and be operated by bevel or other gear from the shaft f
67 is a valve in the end of the cylinder and 68 is its spring, it is operated by
a cam a¹ on the shaft a". h and jare a pair of valves in the end of the cylinder c,
they are operated by a pair of eccentrics g³ on the crank shaft g. The cylinder c
is jacketted and the jacket is divided into two chambers hj₁ by a partition k as
shown in Figures 5 and 6, the valves h and j put these chambers respectively into
communication with the inside of the cylinder.
One end of the cylinder b is connected by a pipe to a refrigerating or cold
storage chamber m (Figure 1) and the other end is connected by a pipe n to a
cooling and drying apparatus o of ordinary construction. The latter is connected
by a pipe p to the chamber of the jacket of the cvlinder c. The chamber j¹
is connected by the pipe q to the storage chamber m and the latter is also connected
by the pipe r to the other end of the cylinder c.
The action of the apparatus is as follows:-On an explosion taking place in one
of the cylinders a the crosshead f is moved from left to right forcing water from
the cylinders & into the accumulator e so storing power. During the whole of this
stroke the valves 67 h and j are closed whilst the valves 65 c5 are open so that the
air in the cylinders b and c passes through the pistons 62 2 from one side to the
other of them. At the end of the stroke the valves 655 close and the valve h
opens admitting compressed air from the cooling and drying apparatus o to the
cylinder c and the pressure of this together with that of the water in the
accumulator e forces the crosshead back again from right to left. During the
whole of the return stroke the valves 65 and are closed. 67 is closed at the
commencement but when the air is sufficiently compressed in the left hand end
of the cylinder b it is opened and the compressed air is forced by the pipe n into
the cooler o. During the whole of the return stroke air is drawn by the pipe
from the chamber m into the right hand end of the cylinder b. When the first
portion say one third of the return stroke has been completed the valve h closes
and the air in the right hand end of the cylinder expands. This cylinder is so
proportioned and the timing of the valves so regulated that if no more air were
admitted there would be a partial vacuum at the end of the stroke but after a
time say two thirds of the return stroke the valve j opens and the cylinder c then
acts as a pump drawing air from the chamber m by the pipe 7 and this air which
is only moderately cold mixing with the extremely cold expanded air in the
cylinder c raises its temperature so reducing loss of cold in the pipe r leading back
to the chamber m. It will be observed that during the time or most of it when
the cylinder c is acting as a pump the valve 67 is open and less power is required
to move the crosshead.
In cases where it is desired to mix a large proportion of moderately cold air
with the extremely cold expanded air the above described arrangement is replaced
or supplemented by a pump or fan drawing air from the chamber m and delivering
it to the piper at or near to the cylinder c.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. The combination of single acting compression, expansion and power cylinders
with means for storing power, the arrangement being such that gas is compressed
in the compression cylinder during the return stroke of the power cylinder by

page_text: means of the expansion of gas in the expansion cylinder aided by the stored
power.
2. In apparatus such as is referred to in Claim 1, employing for the storage
of power a hydraulic cylinder or cylinders in constant communication with an
accumulator.
3. The combination of single acting compression and expansion cylinders, a
single acting power cylinder or cylinders at the side of the compression cylinder,
a hydraulic cylinder or cylinders in constant communication with an accumulator
at the side of the expansion cylinder and a crosshead between the compression and
expansion cylinders to which the piston rods of all the cylinders are fixed.
4. The arrangement of the cylinders substantially as described and illustrated
in the drawings.
5. The combination with the subject matter of the preceding claims of valves
in the pistons or cylinder ends or both of them.
6. A single acting compression cylinder having its valves in its piston and
end.
7. A single acting expansion cylinder having its valves in its piston and end.
8. In apparatus such as is referred to in the three preceding claims operating the
valves in the piston from the connecting rod.
air.
9. Jacketting the expansion cylinder with the incoming compressed and cooled
10. Jacketting the expansion cylinder with air from the cold storage chamber.
: 11. Admitting moderately cold air into the expansion cylinder towards the end
of its expansion stroke.
12. Mixing at or near the expansion cylinder the expanded and extremely cold
a with moderately cold air.
:
13. The compression cylinder and its valves substantially as described and
illustrated in the drawings.
14. The expansion cylinder and its valves substantially as described and
illustrated in the drawings.
15. Refrigerating apparatus substantially as described and illustrated in the
drawings.
Dated this 11th day of January 1899.
TANNETT-WALKER.
F. W. TANN.
D. MCGILL.