ROVEMENTS IN APPARATUS FOR COOLING AND REFRIGE- RATING LIQUIDS
Year: 1882

page_text: LETTERS' PATENT to Carl Pieper of Berlin in the Empire of Germany but
"
at present of The Royal Hotel Blackfriars in the City of London for an
Invention of IMPROVEMENTS IN APPARATUS FOR COOLING AND REFRIGE-
RATING LIQUIDS" Communicated to him from abroad by Hermann Egells
of Berlin in the German Empire, Engineer
PROVISIONAL SPECIFICATION left by the said Carl Pieper at the Office of
the Commissioners of Patents on the 7th October 1882.
CARL PIEPER of Berlin in the Empire of Germany but at present of The Royal
Hotel Blackfriars in the City of London "IMPROVEMENTS IN APPARATUS FOR
COOLING AND REFRIGERATING LIQUIDS" [Communicated to him from abroad by
Hermann Egells of Berlin in the German Empire, Engineer]
.
In the Specification to Windhausen's Patent of the 25th April 1878 No. 1678
and Pieper's Patent of the 17th May 1880 No 2010 are described apparatus for
refrigerating and congealing water by evaporation under pressure very greatly
reduced by the use of a compound- or duplicate exhausting pump in combination
with appliances for absorbing the vapour by means of sulphuric acid, and in the
same Specifications are described apparatus for reconcentration of the sulphuric
acid and for economising the heat employed for that purpose. . This invention
relates to modifications in the construction of parts, of such apparatus so as to
render them more simple efficient and durable, and to convenient arrangements
of the apparatus so as to render it applicable generally for cooling and refrigerating
purposes. The improved apparatus for re-concentrating the sulphuric acid
consists mainly of a cylindrical vessel having a conical cover all lined internally.
with lead and having in its lower part several concentric coils of pipes made of or
covered with lead. The lead lining is secured to the metal of the vessel by dovetail
plugs of lead entering dovetail recesses in the metal and behind the lead lining
there are recesses in the metal which communicate with the interior of the vessel

page_text: at-its upper part so as to maintain equal pressure on both sides of the lining which
otherwise might tend to collapse when the interior of the vessel is subjected to
exhaust. The cover and bottom of the vessel are secured to its middle body by
flanges bolted together and at those junctions the linings are flanged outwards so
that there are two thicknesses of lead between the metal flanges. Each of the
pipe coils is connected. by branches passing through the bottom of the vessel to n
steam pipe and to a condensed water pipe arranged below the vessel, the junctions
The branch
of each coil being separate so that any of the coils can be detached.
pipes of the coils pass through sockets in the bottom of the vessel, these sockets
having a lead lining fused to them so as to form one piece with the general lining.
The vessel has a glass gauge to show the level of the acid which should be above
the coils and it has a lateral supply pipe above this level and a discharge pipe
near the bottom. The junctions for these pipes which are of lead and for the
communications to the glass gauge are all carefully lined with lead. From the top
of the vessel a pipe leads to an annular casing within which is a suction pump;
this casing operating as a condenser for which purpose it is supplied with a water
jet. Under the concentrating vessel is a lead lined receptacle to receive the
concentrated acid and the upper part of this receptacle communicates by a pipe
with the suction pump so that the pressure within it is the saine as in the con-
centrating vessel. There is also below the concentrating vessel another lead lined
tank from which is drawn the dilute acid that has to be concentrated. The pipes
supplying the dilute acid on its way to the concentrating vessel branches out into
a number of small pipes which extend upwards through a casing through which
passes downward the concentrated acid on its way to the receptacle. Thus heat
is transferred from the concentrated neid to the dilute acid. In order to render
this heat exchanging apparatus more effective transverse plates are arranged within
the casing having holes through then a little larger than the small pipes which
extend through them so that the hot acid from the concentrator is made to pass
in thin annular films along these pipes which conduct the colder acid to the
concentrator. The pipe coils in the concentrating vessel being supplied with steam
and the suction pump being worked so as to maintain a partial vacuum, the dilute
acid flows from its tank through the small pipes of the heat exchanging apparatus
and enters the upper part of the concentrating vessel heated, while the concentrated
acid flows from the lower part of the concentrating vessel through the casing of
the heat exchanger becoming cooled as it passes to the receptacle, the concentrating
operation being thus continuous.
The parts of the apparatus employed for producing ice are substantially the
same as those described in the Specification No. 2010 of 1880 above referred to
except that the pumps P1 P2 Fig 1. are dispensed with, these being rendered
unnecessary by the employment of the tank for dilute acid and the receptacle for
concentrated acid mentioned above as forming, part of the concentrating apparatus.
Thus when the acid in the absorbing vessel lias to be changed the dilute acid is.
run into its tank, and a cock or valve being then opened in a pipe leading from
the receptacle of concentrated acid, a charge of this, acid is drawn into the absorbing
vessel when the pressure therein is reduced by the action of the compound or
duplicate vacuum pump. Instead of producing blocks of ice within the refrige-
rating vessels, it is in some cases of advantage.merely to cool more or less water
or other liquid. For such purposes the refrigerating vessels are preferably made
in the form of cylinders placed horizontally with agitators revolving within thom.
The cylinder is somewhat more than half filled with the liquid which is kept in
agitation while it is subjected to the exhaust and absorption, and thus it is rapidly
and considerably cooled. Brino or other uncongeable liquid inay bo thus cooled
to a very low temperature and may be made to circulate around vessels containing
water so as to produce ice as in many ice making machines. Or water may be
cooled but not to freezing point and made to circulate through coolers such as are
used in breweries for cooling wort. Or the wort itself or other liquid requiring to

page_text: be cooled may be acted on directly by passing it through the cylinders subject to
agitation, exhaust and absorption. When liquids are thus treated directly they
are somewhat reduced in volume by evaporation and therefore it may sometimes
be necessary to supply them to the cooling apparatus sufficiently diluted to allow
for the loss by evaporation or preferably to dilute them after cooling as this in
many cases will dispense with the cooling of the diluent. When it is required to
cool down only to a moderately low temperature, the absorption of the vapour by
acid and consequently the concentrating apparatus may be dispensed with, the
vacuum pump being made of a sufficient capacity to remove the low pressure vapour
as it is generated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Carl Pieper in the Great Seal Patent Office on the 2nd April 1883.
CARL PIEPER, of Berlin, in the empire of Germany, but at present of the Royal
IMPROVEMENTS IN APPARATUS FOR
Hotel, Blackfriars, in the city of London,
COOLING AND REFRIGERATING LIQUIDS," a communication to me from abroad by
Hermann Egells, of Berlin, in the German empire, Engineer.
This invention relates to apparatus for refrigerating water in order to congeal
the same and for cooling liquids in general, and it consists in improvements in the
ice-making machine of Windhausen described in the specifications of the patents
N° 1678, A.D. 1878 and N° 2010, A.D. 1880, in which the ice or cold is produced
by the evaporation of water under pressure very greatly reduced by the use of a
compound or duplicate exhausting pump in combination with appliances for
absorbing the vapour by means of sulphuric acid, and for reconcentrating the acid
after having becoine diluted.
The improvements comprise modifications in the parts of such apparatus whereby
they are rendered more simple, efficient and durable, and special arrangements of
the apparatus serving to make it more conveniently applicable for refrigerating
purposes in general and for producing ice by the medium of suitable liquids cooled
to a temperature below the freezing point of water. These improvements are
represented on the annexed three sheets of drawings.
Fig. 1 is an elevation partly in section of the improved apparatus for freezing
water directly by evaporation. Fig. 2 is a sectional view of the acid concentrating
apparatus, and Fig. 3 horizontal section of the boiler thereof. Figs 4, 5 and
show details of the lining of the said boiler. Fig. 7 is a sectional view of the
arrangement of the apparatus for cooling liquids without freezing them, and for
indirectly producing ice by means of such liquids.
The refrigerators A, the absorber B, the compound air-pump D, and the heat
exchanging apparatus E shown in Fig. 1, are substantially the same as in the machine
described in the specification of the aforesaid patent N° 2010 A.D. 1880. Tho
concentrator O, Figs 1 and 2, is also constructed on the same principle as formerly,
inasmuch as it consists of a closed cast iron vessel lined with lead, in which the
neid diluted in B by the absorption of vapour, is heated by steam passing through
coils of pipes K, while a vacuum is created above the acid; but certain new parts
have been introduced and the connections have been so arranged that the pumps
formerly used for pumping the acid into and out of the concentrator are not
any more required.
The passage of the acid through the apparatus is caused by means of the air-
pump F which serves to keep up the vacuum in the concentrator C and to draw off
the vapour evolved from the acid. In order to promote the removal of the vapour,
a condenser R supplied with a water jet, is combined with the pump in the
manner shown in the drawing, or it is placed between the pump and the
concentrator. His the pipe leading from the condenser to the concentrator.
Instead of the air-pump shown, a compound air pump or any other suitable
exhausting apparatus or ejector working by means of steam, air or water, may
bc used.
The concentrated acid is contained in a receptacle G, which is ordinarily placed
at a lower level than the concentrating vessel, so that the acid may flow by gravity
through the connecting pipe L from 0 to G. This receptacle is hermetically
closed and from its upper part a pipe J extends to the suction pump For any part
communicating therewith, such as the pipe H, so that, when the cock J' inserted

page_text: in. J, is open, the pressure within the said receptacle is the same as in the.
concentrator. N is the receptacle containing the dilute acid that has to be
concentrated. The same is open to the atmospheric pressure, and it is also, by
preference, placed below the concentrator. When these receptacles are made of a
material which is apt to be corroded in a prejudicial measure or destroyed by the.
acid, they have to be lined with lead.
,
Between the concentrator C on one hand and the receptacles N and G on the
other, the heat exchanging apparatus E is placed as in the former machine. The,
same consists of a casing or cylinder containing the pipes E', the casing being
connected by pipes L to the lower part of the concentrator and to the receptacle G,
while the pipes E' communicate with the pipes M, and by means of these with the
receptacle N and with the upper part of the concentrator. In consequence of this.
arrangement the hot concentrated acid will flow downward around the pipes E',
while the weak acid which is cold, ascends within them, the latter being thus
heated on its way to C by the concentrated acid, which for its part, is cooled. In
order to render the transferrence of heat from the hot acid to the cold acid more.
complete, transverse plates e are arranged within the casing of E having holes a
little larger than the pipes El which extend through them, so that the hot acid
from the concentrator is made to pass in thin films along the said pipes. This
apparatus presents material advantages in respect to saving of heat; nevertheless
it may be dispensed with if desired.
The concentrator is conveniently made as shown, of cylindrical form with a
conical top. The heating pipes K, which are made of, or covered with lead, are
preferably arranged in several separate and concentric coils. Each of these coils
communicates by branches, as shown in Figs. 2 and 3, with two pipes S and W,
the one conducting steam to the coils from a boiler, and the other conducting back'
to the boiler the water of condensation. The junctions of each coil are separate,
so that any one of the coils can be detached independently of the others.
A partial vacuum having been created by the pump F, and the cock M' being
open, acid will be sucked from the receptacle N through the pipe M into the
concentrator. After having been freed from the excess of water by the combined
action of the steam in the coils K and of the vacuum, the acid is allowed to flow
off by the pipe L into the receptacle G. The flow of the acid through the pipes
may be so regulated by the cocks. M' and L' that the supply to the concentrator
from N, and the discharge from the same to G will be continuous and in proportion
to the concentrating capacities of the apparatus.
It is not absolutely necessary that the receptacle G be placed lower than the
concentrator; the same may be arranged at an equal height, or even somewhat
higher, but in this case a flow of acid from C to G can only be produced by
employing means for creating a higher vacuum in G than in C.
Between the receptacle G and the absorber B, Fig. 1, communication is established
by the pipe P, while O is the pipe conducting the acid from B to the vessel N. The
acid in B having become diluted to such a degree as to be lacking in efficiency, the
absorber is shut off from the refrigerators and air admitted into the same. The acid
is then drawn off by cock O' into N. A vacuum having thereupon again been
created in B, the cock P¹ opened and air admitted into G by the cock J¹, which is
provided with three ways, or by other suitable means, concentrated acid will be
sucked into B from G. The entrance of air meanwhile into C by the pipe L, may
be prevented by a check-valve or by the cock L'. When the absorber is filled to
the required level, the cocks P¹, J and L' (the latter in case of its having been
used) are then again adjusted as before. A periodical emptying and filling of the
absorber B has thus to take place, while the concentrating operation goes on
continuously.
As has been mentioned hereinbefore, the concentrator is provided with a lead
lining. This lining is secured to the iron by means of dovetail plugs of lead a
inserted into dovetail recesses in the walls of the vessel, as shown in Figs 4 and 5.
In order to carry out this mode of fastening, a hole is cut into the lining opposite.

page_text: to ench recess, and of about the size thereof. So much molten lead is then poured
into the recess that it will slightly project from the surface of the lining, whereupon
its edges are liammered close to and over the edges of the latter. Finally the edges
of both parts are fused together by means of a gas blow-pipe. The plugs may,
however, also be formed by inserting a piece of lead of suitable form and size, into
each recess, and expanding it by hammering,
•
As there is a vacuum inside of the concentrator, any air penetrating from the
outside, or moisture happening to enter between the wall of the vessel and the lining,
will have the tendency to cause the lining to bulge inward. To prevent this,
annular grooves b, Figs 2 and 4, are made in the iron, and these are all put in
communication with a pipo è which extends nearly to the top of the vessel and
terminates in a downward bend so as to preclude the entrance of acid into the pipe.
The pressure between the lead lining and the outer iron case is thus maintained the
same as that within the vessel. Such of the grooves b as are sufficiently high above
the level of the acid, may simply be put in communication with the inside of the
vessel by a hole d in the lining, (see Fig. 5); but, in order to prevent any acid from
finding its way into the said hole, it is advantageous to protect the same by a cap f
having perforations f, through which any air or vapour from behind the. lining
may pass out.
Wherever pipes branch off from the concentrator, the lend lining extends into
and through the same, as shown in Figs 5 and 6, the latter figure representing
in section a tubular attachment through which a branch of one of the pipes S
and W posses.
Instead of producing blocks of ice within the refrigerating vessels, it is in some
cases of advantage merely to cool more or less water or other liquid. For such
purposes the modified arrangement represented by Fig. 7 is preferably employed.
The refrigerators A are, in this case, constructed in the form of cylinders placed
horizontally, and they are provided with agitators revolving within them for the
purpose of stirring the liquid, so as to increase its evaporating surface and thereby
to accelerate the cooling process. The said cylinders are in communication with
the absorber B containing sulphuric acid and connected with the air-pump D as in.
the apparatus described first. The cooled liquid is made to circulate by pumps
arranged at Q and by the pipes Rº, through the rooin or vessel in which the cold
is to be utilized, as for instance through coolers such as are used in breweries, for
cooling wort, while it returns by the pipes R to the refrigerator to be cooled again.
Or, the wort itself or other liquid requiring to be cooled is acted on directly by
being passed through the cylinders A. A pipe with cock T serves to introduce
water in order to compensate the losses due to evaporation.
If the liquid exposed to evaporation is of a nature that it may be cooled to a
very low temperature without freezing, as is for instance the case with a solution
of chloride of calcium, or of other salts, it may be employed for congealing water
contained in special vessels. For this purpose the cooled liquid is caused to
circulate in pipes arranged in coils or serpentines within a tank S' also containing
a liquid uncongealable at the temperaturo in question. In the latter liquid the
vessels U containing the water to be converted into ice, are suspended. In order
to maintain the temperature of all portions of the said liquid uniform, it is advan-
tageous to provide this apparatus also with a mechanical stirrer V, as shown in the
drawing. It is, however, not absolutely necessary to fill the tank S₁ with liquid.
The transmission of heat from the water to be frozen to the primary refrigerating
liquid, may also take place by the medium of the air surrounding the vessels with:
water and the serpentines, and by the radiation of the former. In the third place
the said cooling liquid may itself be caused to circulate around the vessels U
suspended in the tank S'; but in this case the joints between the flanges of tho
said vessels and the edges of the openings serving to receive them, must be made
hermetically tight. The said freezing-tank S₁ by itself I do not, however, claim
as new.

page_text: The arrangement of the apparatus for concentrating the sulphuric acid shown in
Fig. 7 is substantially the same as the one represented in Figs. 1 and 2.
Having thus described the nature and object of this Invention and the manner
in which it is to be carried out in practice, as cominunicated to me by my
correspondent, I hereby claim as new and important features of the same:
1. The concentrator C, the air pump F, or its described equivalent, the closed
receptacle G, the receptacle N and the connecting pipes H, J, L and M, combined
together substantially as and for the purpose specified.
2. In combination with the concentrator C, the lead lining attached to the walls
thereof by means of the dovetail plugs a, as herein before described.
3. In the concentrator C provided with a lead lining, the grooves 6 communicating
with the space above the acid, substantially as and for the purpose stated.
4. In an apparatus for cooling liquids by the evaporation of water in vacuo,
which comprises the absorber B, the compound exhausting pump D, the concen-
trator C, the air-pump F or its equivalent, the receptacles G and N, and the pipes
H, J, L and M, as described: the use of a refrigerator A consisting in a horizontal
cylinder with mechanical stirrer, in combination with a pump and pipes adapted, to
convey the cooled liquid to the place where it is to be utilized, (as for instance the
freezing-tank S¹) and back to the refrigerator, and a supply-pipe T for introducing
water into the refrigerator during the cooling process in order to compensate the
losses by evaporation, substantially as hereinbefore specified.
In Witness whereof, I the said Carl Pieper, have hereunto set my hand and
seal this twenty-seventh day of March in the year of our Lord One
thousand eight hundred and eighty-three.
'
CARL PIEPER (L.S.)