IMPROVEMENTS IN DRY AIR REFRIGERATING AND APPARATUS THEREFOR
Year: 1879

page_text: LETTERS PATENT to Kennard Knott, junior, of 283, Strand, in the County of
Middlesex, Refrigerator Builder, for the Invention of "IMPROVEMENTS IN DRY
AIR REFRIGERATING AND APPARATUS THEREFOR."
Sealed the 18th November 1879, and dated the 21st May 1879.
PROVISIONAL SPECIFICATION left by the said Kennard Knott at the
Office of the Commissioners of Patents on the 21st May 1879.
KENNARD KNOTT, junior, of 283, Strand, in the County of Midddlesex,
Refrigerator Builder. "IMPROVEMENTS IN DRY AIR REFRIGERATING AND APPARATUS
THEREFOR.
"
My object in this Invention is to obtain a continuous supply of cold to the
cooling chamber, and I purpose accomplishing this in the following manner :-My
apparatus consists of the cooling chamber constructed in the ordinary manner, and
of any convenient shape and materials; this chamber is to contain the articles to
be kept or cooled. Inside this cooling chamber, and preferably at the top thereof,
I place a series of small tanks or coils, or one tank or coil (if tanks are used, I
prefer to form them of corrugated metal, to obtain greater cooling surface), connected
together, if more than one be used, and all communicating with a pipe or pipes
leading to a pump; underneath the tanks or coils I place gutters, preferably of
wood, to carry off the moisture formed upon them; the gutters can discharge by a
cross gutter into a waste pipe. prefer to conduct part of this piping within the
thickness of the side or wall of the cooling chamber, though this is not absolutely
essential to iny Invention. To the other end of this series of cooling coils or tanks
is attached a pipe, the other end of which communicates with another tank or
reservoir outside the cooling chamber, which I call the container. Returning now
to the pump, which I prefer to make double acting, and which may be driven by
any suitable means, a pipe connects this with a condenser which is formed upon the
well known surface-condensing principle, though the precise form may be con-
siderably varied. One method is to make it of an oblong chest, inside which is
placed a hollow metal closed receptacle of a horse-shoe-magnet shape, outside which
water circulates through the chest; to one end of this receptacle is attached a pipe
coinmunicating with the container previously mentioned. It will be seen that a
complete circle of piping, et cetera, is thus established. I place what I term a
pressure valve" on the pipe, preferably between the condenser and the container;
"

page_text: this valve being loaded either by spring or weight, and so constructed that no
fluid can pass until a certain minimum pressure is attained, somewhat like
the action of an ordinary safety valve, and so arranged that the amount of pres-
sure can be varied as desired. I also prefer to place a supply tank in a suit-
able position communicating by a pipe with the pipe leading to the container;
these pipes I connect by means of a three way cock, so that I can close the
passage from the condenser and open that between the supply tank and the container,
when desired, to make good any loss by leakage or otherwise. If preferred, the
supply tank can communicate direct with the container, instead of with the pipe
leading thereto, in which case, I should dispense with the three way cock, and
employ two ordinary cocks instead. The action of the apparatus is as follows:-I
place in the container a suitable quantity of acid, and the pump being set in motion,
the vapour from the container travels along the pipe leading to the cooling chamber,
and thence through the series of tanks or coils within the chamber to the pump.
After passing the pump it is forced through the piping and condenser to the pressure
valve, and through it back to the container. It will be seen that by regulating the
load upon the valve, any desired pressure may be maintained within the pipes and
condenser between it and the pump, and the vapour condensed on its way back to
the container. The stream of water circulating through the condenser abstracts the
heat from the acid passing within.
In places where a fall or other pressure of water cannot conveniently be obtained,
I employ a second pump, either in connection with the first one or independent of it,
to circulate the water through the condenser. In this process, I prefer to use
anhydrous sulphurous acid, but may employ any other known suitable chemical.
This Invention can be applied to stationary purposes, or it may be fitted
on board ships, with such variations of detail as may be necessary, or to rail-
way carriages. In this last case I should prefer to utilize the motion of the
axles when practicable as the motive power, and for the stream of water through
the condenser should most likely require the supplemental pump already men-
tioned, the supply of water being carried in tanks wherever found most convenient,
as underneath the carriage, on top, or even within the cooling chamber itself.
In default of obtaining the power from the axles, some other motive power
may be introduced. The supplemental pump might also be required on board ship,
and sea water used for circulating, if the temperature thereof were not too high. I
am aware that the system of obtaining cold by the alternate vapourization and
condensation of chemicals, in connection with a more or less complicated and
expensive arrangement of pipes, tanks, etcetera, containing brine or other uncon-
gealable liquid, has been in the manufacture of ice; but so far as I am aware, the
plan here described of making the coils or tanks within the cooling chamber itself,
form part of the primary circle of piping, etcetera, is novel, and by dispensing
with the brine and apparatus connected with it, I effect a very great reduction in
the first cost of the whole apparatus, and in the subsequent cost of working. I con-
sider also that the continuous and finely adjustable pressure obtained by the intro-
duction of the pressure valve is of considerable importance in this process.

page_text: A, Fig. 1, is the cooling chamber in which the articles to be preserved or cooled
are placed; this is composed of double walls with a space, between which is filled
with some non-conducting substance, such as charcoal. B is the container (the
precise form of this is not very important, though I prefer that adopted in the
Drawing) for the chemical, connected by pipe B' with the tank C, which I prefer to
place at the top of the chamber A; this pipe inay be carried as far as possible
through the non-conducting material between the inner and outer walls of the
chamber as shown. D is a pump, preferably double-acting, though not necessarily
so, having its suction branch connected by pipe B2 with one end of tank Č.
The discharge branch of the pump is connected by pipe B³ with the condenser E,
the other end of which is joined by pipe B' to the regulating valve F (or its
equivalent), which in its turn is joined to the container B by pipe B5, thus com-
pleting the circle. The condenser E is surrounded by a casing or cistern G, which
is supplied with a constant stream of cold water either from the exhaust of the
pump cylinder, if water power be used for the pump, or by a pipe from a reservoir
or main. The upper surfaces of the condenser are corrugated to increase the cooling
surface, while the lower portions are left plain so as not to impede the flow of
condensed vapour to the container. Should the corrugations be placed lengthwise,
as in Figs. 11 and 12, this would not be of so much importance. The pipes shown
dotted and in full in the Drawing represent the methods of connection either for
water power or steam-pipe, D' would be the exhaust if water power were used.
The container B is also surrounded with a casing which is filled with non-conducting
material instead of water. A reservoir or supply tank, not shown in the Drawing,
may also be provided when found advantageous to contain a supply of the chemical;

page_text: this supply tank is then connected by another pipe with pipe B, and a three-way
cock inserted, so that the passage between the condenser and the container may be
closed, and that between the supply tank and the container opened to let in more
of the chemical to make up for loss by leakage or otherwise, or for charging the
container in the first instance. The supply tank could of course be connected
direct with the container instead of with pipe B, but I do not recomined this plan.
The gutters H are shown in position under the tank C, the drip being taken off by
means of a small pipe I as shown. I generally make the gutters discharge into one
cross gutter, and take the pipe I from the end of this cross gutter, or the cross
gutter may be omitted, and each gutter have a small pipe of its own. These waste
pipes should be syphoned, or they may all be joined into one larger waste pipe
which may be syphoned to keep the external air out. These gutters, Fig. 16
(Sheet 3), are a very important feature in my Invention, as many different plans
have been tried for preventing the moisture collecting upon them and dropping
down upon the articles placed in the chamber, but so far as I am aware, those which
I am about to describe are the only ones which have really accomplished this.
Fig. 15 shows the gutters H in position under the tank, a cross gutter H' running
across the ends as already described; Fig. 16 is a detailed view of them, and Fig.
17, a modification of the same. I form the gutter body of any suitable material,
but prefer to employ good sound timber, one piece overlapping the other as shown.
All joints are made as tight as possible, the parts being nailed, screwed, or other-
wise firmly fastened together, and a little paint, tar, whitelead, or the like, is
generally added to make the joint quite tight. Round this gutter I wrap felt,
flannel, or a like non-conducting substance, so as to cover all parts, except such as
slant down towards the inside of the gutter where any moisture collecting may run
down the angle formed for the purpose. The ends of the gutters may be stopped
(though in the alternative arrangement shown at Fig. 17 I do not generally use
ends, and have put them in the Drawing merely to show how they can be applied),
the joints being secured, and felt or zinc laid over like the rest of the gutter; a
small piece of pipe being let into one end to take off the condensed vapour. Along
the inside faces of the gutters I place zinc or other suitable metal, such as galva-
nized iron, which I fasten carefully down upon the felt by nailing or other
convenient and suitable method; this forms a good channel for the vapour to
condense on or run down. A tack of solder may be placed round the nail heads to
prevent any moisture getting through the nail holes. In Figs. 16 and 17, a is the
body of the gutter; b, the felt or flannel and the zinc or iron. A cover with
flat bottom and sloping top is provided above the opening between each gutter;
this is covered with felt as before, and has its upper side also covered with zinc
(like the insides of the gutters), the metal being extended downwards and outwards,
so as to allow the moisture to drip into the gutters below, all this is clearly shown
in Fig. 16. Fig. 17, as stated, is only a modification of the foregoing, and is self-
explanatory, and it will be seen that in both these plans, a clear course is provided
for the circulation of the air, while as the drip collects only on the metal of the
tanks and gutters, it can only drop into the gutters themselves and be properly
carried off, instead of dropping on to the articles below, as has generally been the
case hitherto. Other modifications might be made in the actual form or shape of
gutter employed without departing from the principle of my Invention.
:
METHOD OF WORKING.
This will be best understood by reference to Fig. 1 (Sheet 1). The first thing to
be done when starting the apparatus for the first time, or after it has lain by for a
time, is to extract the air. This I prefer to do by turning the three way cock K
(placed as near as practicable to the discharge branch of the pump on pipe B³), so
as to close the connection with the pipe, and open one directly with the atmosphere.
I then start the pump which draws the air out of the circle of pipes, tanks, etcetera,

page_text: and forms a more or less perfect vacuum; the cock K is then turned back, and the
connection between pump D and pipe B³ re-established. Acid is then let into the
container B either from the supply tank, if one be provided, from a drum of acid by
means of an air-tight coupling, or in any other convenient manner, and the vapour
from the container B is drawn through the pipe B¹ leading to the cooling chamber
A, and thence through the tanks or coils C within the chamber, and pipe B2 to the
pump D. After passing the pump D, it is forced through the pipe B³, condenser E,
and pipe B, to the pressure-valve F (or its equivalent), and through it and pipe B³,
back to the container B. It will be seen that by regulating the load upon this
valve (or the diameter of the piece of small pipe, or the area of the orifice of the
cock or screw-valve, if one of these be used), the pressure within the pipes Bs and
B, and condenser E (between the pump D and valve F, or its equivalent), may be
nicely adjusted and regulated, so as to obtain the best results. If preferred, the
pressure valve F, or its equivalent, may be placed between the condenser E and
pump D (though where practicable, I prefer the other arrangement), so that tho
condenser may not have to bear the extreme pressure caused by the resistance of
the valve F or its equivalent. As substitutes for the valve F, I can use other forms
of valve, such as an ordinary throttle-valve, a screw down which could be
adjusted to a certain size of orifice, an ordinary cock which could be similarly
adjusted, or a short length of pipe of a small diameter, so as to restrict the
passage of the acid, and cause it to be highly compressed by the pump.
stream of cold water circulating through or around the condenser abstracts the
heat from the acid passing within. In places where a fall or other pressure of
water cannot easily be obtained for circulation about the condenser, I may employ
a second pump either in connection with the pump D, or independent of it, to force
the water through the condenser. The acid which I prefer to use in this apparatus
is anhydrous sulphurous acid, but the apparatus is constructed so as to work with
almost any of the well-known chemicals or chemical compounds that vapourize
readily, and can be recondensed in the manner described.
The
The apparatus as above described is adapted to most kinds of cooling purposes
where a stationary chamber or room is required, but it is evident that the same
apparatus, or in a slightly modified form, is also applicable for use on shipboard, in
railroad cars, etcetera, where the whole apparatus is carried about with the ship,
car, etcetera. On shipboard there is usually no lack of power for driving the pump,
and in steam ships, this may sometimes be advantageously done by means of a belt
and suitable pulleys (if the cooling chamber be placed sufficiently near the engine
room) from the shaft of the main engine, the connections in each case being made
to suit that particular case. Where the condenser is placed low enough in the
vessel, connections may be made with the outside, so as to allow of the sea water
(except perhaps in very hot latitudes, when the water might require to be
artificially cooled before it could be used for the condenser), circulating through or
around the condenser, one pipe pointing towards the bows of the vessel, and having
a funnel-shaped mouth for the intake, and the other pointing astern for the discharge.
If necessary, the discharge may be raised a little above the intake, so as to escape
the pressure of the water at its mouth, the speed of the vessel being considered
sufficient to force the water through the pipes and condenser, and out again. The
same end may also be attained by the use of the supplemental pump already
mentioned. In the case of railroad cars. power for driving the pump may be
obtained from one or more of the axles, an eccentric being preferably employed to
work the pump; gearing might be used, though I do not recommend this plan.
A belt or chain passing round a pulley on the axle, and up through the carriage-floor,
may sometimes be employed with advantage. The stream of water would be.
obtained by means of the supplemental pump from a supply tank carried upon the
car itself. If it be not convenient to take the power from the axle,.some other
means may be employed, such as a small steam or gas engine; in the former case
the car might be placed next to the locomotive, and steam be obtained therefrom
through a flexible hose. It sometimes happens that where the top. of the chamber.
+

page_text: is low, the whole of the available height must be left clear for hanging large articles,
such as sides of beef, etcetera, and I cannot then place the tanks or coils at the top
of the chamber. In such cases, I place them in the most suitable position obtainable
(as at the sides or ends), and as the warmer air is apt to remain in the centre near
the top, and the moisture contained in it might, if left long enough, coudense on the
beef or other articles to be preserved, I find it advisable to circulate the air in the
chamber artificially.
I am aware that the principle of obtaining cold by the alternate vapourization
and condensation of chemicals or chemical compounds generally in connection with
a more or less complicated and expensive arrangement of pipes and tanks containing
brine or other uncongealable liquid, has been used in the manufacture of ice, or for
cooling fluids placed in direct contact with the tanks; but so far as I am aware,
the plan here described of placing the coils or tanks within the cooling chamber (for
refrigerating or preserving perishable articles) itself, so as to form part of the
primary circle of piping is novel, and by dispensing with the uncongealable liquid
and apparatus connected therewith, I effect a very important reduction in the first
cost of the apparatus, and in the subsequent cost of working it.
Having now fully described and ascertained the nature of my said Invention, and
the best method known to me of carrying it into effect, I wish it to be understood
that what I claim and desire to protect under the hereinbefore in part recited
Letters Patent is,―
Jst. The refrigerating apparatus herein described and shown, consisting essentially
of the combination of the container B, tank or coil and cooling chamber C and A,
pump D, condenser E, and valve F (I do not claim the valve F as shown in Figs. 1
and 2 by itself) or its equivalent, all forming part of the same primary circle.
2nd. The manufacture of refrigerating apparatus in which the cooling chamber A
is arranged around or combined with the tank or coil C, said tank or coil being
placed in and forming part of the primary circle, substantially as set forth and
shown.
3rd. In refrigerating apparatus, the application between the pump and the
container (in the section of piping in which is placed the condenser) of a cock,
screw down valve, throttle-valve, piece of pipe of smaller diameter than the rest, or
similar appliance, the area of the passage through which can be adjusted, set, or
formed to a fixed amount, so that the pressure between said pump and container
may be thereby increased for the purposes of compression or condensation of the
vapour, substantially as set forth.
4th. In refrigerating apparatus, the application of the cock K, whereby the pump
D may be used to exhaust the air from the container and circle of piping when
required, substantially as set forth and shown.
5th. In refrigerating apparatus, the manufacture of corrugated condensers E,
substantially as set forth and shown.
Gth. In refrigerating apparatus, the manufacture of condensers L, E, of a horse-
shoe-magnet shape in section, with or without cross tubes M, or corrugations E¹,
substantially as set forth and shown.
7th. In refrigerating apparatus where cold is obtained by the vapourization of
the refrigerating agent, the manufacture of tanks or receptacles with corrugated
bottoms, as in Fig. 7, in sections connected together by short lengths of pipe, as in
Fig. 8, or with widely separated receptacles connected by one or more horizontal or
vertical rows of pipes or tubes as at C, Figs. 3 and 1, substantially as set forth and
shown.
8th. In refrigerating apparatus, the method here described and illustrated, of
partially or entirely covering the gutters H with felt, flannel, or the like non-con-
ducting material, and the combination therewith of a metallic lining or covering for
the upper part of said gutters.

page_text: 9th. In refrigerating apparatus, the manufacture of gutters H as described in
claim 8th.
In witness whereof, I, the said Kennard Knott, junior, have hereunto set my
hand and seal, this Twentieth day of November, in the year of our Lord
One thousand eight hundred and seventy nine.
KENNARD KNOTT, JUNIOR. (L.S.)
Witness,
ALFRED J. BOULT,
of the Firm of W. P. Thompson, & Co.,
Solicitors of Patents,
323, High Holborn,
London,
and 6, Lord Street,
Liverpool.