Improvements in Refrigerating Machinery.
Year: 1890

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by CARL LINDE, of Wiesbaden, Germany, Professor.]
Improvements in Refrigerating Machinery.
I, THOMAS BELL LIGHTFOOT of No. 35 Queen Victoria Street, in the City of London,
Consulting 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 that description of refrigerating machinery in which coll
is produced by the evaporation of a volatile liquid, the vapours being then compressed
by compressing machinery and cooled in condensers in order to act again by
evaporation.
The present improvements are applicable more particularly to those cases wherein
the difference between the pressure in the evaporating apparatus and that in the con-
denser is very considerable, that is to say, in cases where either the refrigeration has
to be effected to very low temperatures, or only a limited quantity of cooling
water of comparatively high temperature is available.
In such cases the action of compressers is more particularly prejudicially affected
by the dead spaces, and the difficulties of maintaining the valves and stuffing boxes
perfectly vapour tight are considerably increased.
This invention has for its object firstly to remedy the inconveniences arising in such
cases, and secondly to provide means whereby such refrigerating apparatus may be
readily applied to the production of different degrees of cold by a suitable combination
between several evaporating apparatus acting at different temperatures and pressures,
and the compressors. Such a refrigeration at different temperatures takes place for
example in every machine for the production of ice wherein the water to be frozen
and the cooling medium, such as ammonia or carbonic acid, passing from the condenser
to the evaporating apparatus are subjected to a preliminary refrigeration so as to
bring them nearly to freezing point, before passing to the ice making machine.
The above described objects are effected in the first place by the application of
the known system of stage compressing in such a manner that the vapours when
being subjected to the higher stages of compression are always operated upon in
those ends of the compressing cylinders at which there are no stuffing boxes, the other
ends of the cylinders serving to effect the lower degree of compression into a
receiver from which the compressors for the higher stages are supplied.
I will proceed to describe some arrangements for this purpose with reference to
the accompanying diagram drawings.
In the arrangement shewn at Fig. 1, two double acting compressors C and (3
are coupled so that three sides thereof namely both ends of 0 and the stuffing
box end of C draw from the evaporating apparatus A and deliver into the receiver R
from which the other end of compressor draws, and delivers into the condenser
at D.
The low stage compressors can in this case either all draw from one and the
same evaporating apparatus A, or partially from this and partially from a second
evaporating apparatus B, or the vapours from the latter can pass directly into the
receiver as indicated in dotted lines, if they are at a higher temperature and pressure
than those from A.
Or again, the compressor ( can draw from A and the stuffing-box-end of C³
from. B, which gives off vapours at higher pressure, the compressed vapours being
in both cases delivered into the receiver R from which the other end of C² takes for
the high stage compression.
Should either of the compressors get out of order, or if only a less degree of cold is

page_text: required, the two compressors can be made to work independently of each other, by
providing shut off cocks at a b c d e f so as to enable each compressor to be
put in direct communication respectively with the evaporating apparatus and the
condenser.
In the arrangement shewn at Fig. 2 the pistons of two single acting com-
pressors C¹ 02 are combined on one and the same piston rod, the larger one (1
which has the stuffing box being the low stage compressor, taking from the
evaporating apparatus A, and delivering into the receiver R, into which vapour at
higher temperature and pressure from the evaporating apparatus B passes direct.
The compressor C2 on the other hand, which has no stuffing box, takes from the
receiver R and delivers to the condenser D.
The space between the two pistons is put in communication with the receiver.
In the arrangement at Fig. 3 the same mode of operating is carried out as in the
preceding one, the single cylinder compresser being made to do duty as low stage
compresser at Cand as high stage compresser at C, the receiver R from which it
draws being supplied both from the low stage compressor and from the evaporating
apparatus B acting at higher temperature.
Fig. 4 shews an arrangement, by way of example, for carrying out the second
hereinbefore stated object.
The evaporating apparatus A has to maintain the brine required for the production
of ice at several degrees below the freezing point of water.
The evaporating apparatus B is situated in a vessel E, into which the water for
forming the ice enters at its natural temperature, and in which it is cooled down to a
certain degree before passing thence into the vessel F that supplies the ice making
machine G.
The vapour passing from B being at higher pressure than that from A may be
delivered into the receiver of either of the above described arrangements while that
from A is delivered to the low stage compressor; or the vapours from B may be
delivered to a separate low stage compressor.
The vessel E may also contain a tubular apparatus through which the refrigerating
liquid, such as ammonia or carbonic acid, coming from the condenser D is made to
flow before passing to evaporating apparatus A so as to be further cooled either by
the water in E, or by establishing a communication between r and B.
The quantity of heat to be withdrawn from the water to be frozen and the
refrigerating water is considerable, when the natural temperature of the water is
comparatively high, as is the case in tropical countries, and a considerable saving of
work and cost will be effected in such cases by withdrawing the heat at a temperature
which is just above the freezing point of water instead of at the low temperature
of the ice producing machine.
According to another application, the apparatus A serves as air refrigerating
apparatus for producing very low temperatures such as in freezing rooms, while the
evaporating apparatus B may either serve for the production of ice or for the
refrigeration of other spaces or of liquids.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In refrigerating machinery effecting the compression of the vapour in two or
more stages in such a manner that the high stage compressor receives in addition to
the volume of vapour compressed by the low stage compressor, either directly or
through a receiver a further volume of vapour at a higher pressure than that passing
into the low stage compressor, substantially as herein described.
2. In refrigerating machinery the combination of low and high stage compressors
with evaporating apparatus delivering vapour at different temperatures and pressures
and with a receiver, in such manner that the low stage compressor draws from the
low pressure evaporating apparatus and delivers into the receiver, while the high stage

page_text: compressor draws at the end where there is no stuffing box both from the high
pressure evaporating apparatus and from the receiver and delivers into the condenser
substantially as herein. described.
3. In refrigerating machinery the combination of low and high stage compressors
with evaporating apparatus working at different temperatures and pressures, and with
a receiver in such manner that the low stage compressor draws from the low pressure
evaporating apparatus and delivers into the receiver, while the high pressure
evaporating apparatus delivers into the receiver, and the receiver delivers into the
high stage compressor, substantially as described."
4. In refrigerating machinery, the combination of low and high stage compressors
with evaporating apparatus working at different temperatures and pressures in such a
manner, that each evaporating apparatus delivers into a separate low stage compressor,
which deliver into the same receiver, while the high stage compressor draws from
the receiver and delivers into the condenser, substantially as described.
5. In refrigerating apparatus more particularly applicable for ice-making, the
combination of an evaporating apparatus serving to cool the brine for the ice machine,
with a second evaporating apparatus connected to a separate compressor or to a
receiver, for cooling down the water to be frozen and in some cases also the
refrigerating liquid coming from the condenser, substantially as herein described.
Dated this 4th day of February 1890.
ABEL & IMRAY,
Agents for the Applicant.