Improvements in or relating to the Collection and Utilization of Air-free Carbonic-acid Gas from Fermentation, and Apparatus therefor.
Year: 1896

page_text: Date of Application, 11th Feb., 1896-Accepted, 23rd May, 1898
COMPLETE SPECIFICATION.
Improvements in or relating to the Collection and Utilization of
Air-free Carbonic-acid Gas from Fermentation, and Apparatus
therefor.
A communication from THE PABST BREWING COMPANY, a corporation organized
and existing under the laws of the State of Wisconsin, and having its principal
offices at Milwaukee, Wisconsin, United States of America.
I ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Chartered Patent Agent, 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:-
The main objects of this invention are to save in a condition suitable for future
or immediate use the carbonic acid gas produced by fermentation of beer and other
fermentable liquids and to utilize such gas for recarbonating storage beer or other
liquids.
It consists essentially in expelling and excluding air from the gas-collecting
space of a fermenting vessel and conducting therefrom free from air, the gas
produced therein by fermentation, for immediate or future use; in the direct and
continuous process of utilizing such gas for recarbonating the beer or other
beverages from which it has been derived, or for carbonating other liquids; and
in apparatus for performing the above mentioned operations, as hereinafter
specifically explained and pointed out in the claims.
In the manufacture of beer and other similar fermented beverages, large
quantities of carbonic acid gas are produced by fermentation, and are generally
wasted. Efforts have been made to save and utilize this waste gas for
recarbonating beer or other beverages, and for other purposes, but the mixture
of air with the gas has rendered it unsuitable for recarbonating beer and for
similar uses.
Various attempts have been made to separate the air from the gas
after it leaves the fermenting tubs or vessels, and the methods heretofore proposed
for that purpose have generally depended upon the difference in the specific
gravity of air and gas, but it has been found by experience that it is impracticable
to separate the air directly from the gas on account of the tendency of the gas to
diffuse and mingle with the air, even under the most favorable conditions.
Another method of accomplishing this separation is based upon the fact that
water and other liquids under given conditions absorb carbonic acid gas with great
facility, but do not so absorb air. While this process is practicable, it is
somewhat circuitous and complicated. It is found that after active fermentation
sets in, nearly if not quite pure carbonic acid gas is produced while such
fermentation continues, and upon this fact the present improved process and
apparatus are based.
Referring to the accompanying drawing, which shows partly in vertical section
and partly in elevation, apparatus constructed and arranged in accordance with
this invention, A A' and A' designate fermenting tubs, soine of which are such as
are commonly employed in breweries for the manufacture of beer. B designates
an ordinary storage cask, and C an extensible gas holder or receiver provided with
the valved air vent c opening from the highest point of the bell, and with a valve
and hose or pipe connection e' at or near the bottom of the outer or stationary part

page_text: of the receiver for the purpose of filling the receiver with water and withdrawing
the water when necessary. The vent c also serves in starting the apparatus at the
outset to allow any air which may collect in the top of the receiver to be expelled
by inflowing gas. When once in operation it is not intended nor is it necessary to
allow any air whatsoever to enter the main pipe D¹ or gas receiver. D are branch
gas collecting pipes passing between the several rows of tubs and connected by a
main pipe D with the gas receiver C, or with a compressor, carbonator or other
apparatus which is to be supplied with air-free gas.
The fermenting tubs A A in the upper tier or story are of the ordinary open
kind, and are provided with removable bells or hoods a a, approximately fitted into
their open tops and adapted to enclose a space above the surface of the beer or
liquid contained therein. They are suspended over the tubs by chains or cables
passing over suitably located sheaves, and are provided at their apexes or upper-
most points with hose connections, to which are attached sections of hose a¹ a',
provided at their outer ends with couplings and valves a². The gas collecting
branch-pipes D are provided adjacent to the several tubs with hose connections to
which are attached hose sections d d, also provided at their outer ends with
valves d¹ and couplings by which they are connected when desired with the hose
sections a¹.
In the tier or story next below, the tubs A¹ A¹ are perinauently closed and are
provided at the uppermost points therein with air vent valves or connections a³ a³.
They are severally connected at the top with the gas collecting pipes D by branch
pipes d', which are provided with valves d³, and which may terminate within the
tubs in bells or flaring mouths a*.
In the second stery a modified form of open fermenting tubs A2 A2, is shown.
These tubs are provided on the outside at or near the top with annular troughs or
receptacles as a³, for holding water or other suitable sealing liquid, and with
removable bells or covers a a, the rims of which are adapted to enter said
receptacles and thus form a gas-tight enclosure over the open tops of the tubs.
Each of the covers a has a valve-controlled air vent a' leading out of the apex or
upper part thereof, and a valve-controlled gas connection as, which may terminate
inside of the cover with a flaring mouth a', like or similar to those shown in the
tubs A, and provided with a valve and coupling for attachment to a hose section d,
which is connected with one of the gas collecting pipes D. Each bell or cover a
is suspended from a trolley E, adapted to traverse a track e, extending over a
row of tubs, and it may thus be used to collect gas from any tub of the row as
desired, according to the condition or stage of fermentation taking place therein.
The several fermenting tubs may be provided with attempering coils F and F,
as shown, for modifying or regulating the temperature of the fermenting liquid as
desired. The coils F F are arranged so as not to interfere with the operation of
the bells or hoods a a.
The gas pipe D or one of its connections, is provided with a safety valve d' and
waste connection, by which over-pressure is avoided in the gas-collecting system,
including the fermenting tubs, pipes D D¹ and the receiver C. At the lowest
point therein the pipe D' communicates with a trap d', by which any moisture
carried with the gas into and condensing in the gas collecting pipes, is caught and
prevented from passing into the gas receiver C, or producing back pressure in the
fermenting tubs.
G is a gas pump connected on the suction side by a pipe g, with the gas
receiver C, and on the force or discharge side by the pipe gl with one or more gas
purifiers H H. The suction pipe g communicates at the lowest point therein with
a trap 9, by which any liquid drawn into or condensed in said pipe is caught' and
prevented from entering the pump. The traps d' and 9' being open at the top and
having water supply and overflow connections, serve also to prevent over pressure
in the gas collecting system, the maximum pressure attainable being determined by
the height of the water column in said traps. The suction and discharge pipes g
and g of the pump are connected by a by-1 assage or pipe g3 which is provided

page_text: with an automatic regulating valve or device, whereby communication 13
automatically established between the suction and force or discharge sides of the
pump when the pressure on the discharge side reaches a certain predetermined
point.
I is a receptacle for producing a solution of certain sterilizing agents or chemical
substances and delivering it free from air, to the purifiers H, which are supplied
with broken marble or other material presenting an extended surface and tending
to retard the flow of gas through them. The receptacle I has a valve-controlled
water supply connection i and a pipe or hose connection provided with a valve
and coupling at one end for attachment to either of the purifiers H without
admitting air thereto. The sterilizing agents or chemicals placed in said
receptacles are dissolved and taken up by the water as it passes through it into
either purifier, and destroy any organic matter carried by the gas.
designates a condenser, which is connected by a pipe j, with the last of the
series of purifiers H, and has an outlet pipe leading from the lower part thereof
and provided with a reducing valve, whereby the gas is delivered at the desired
pressure. The condenser is provided with a coil 3 through which brine or a
cooling medium is circulated, for the purpose of condensing and collecting any
moisture that may be carried by the gas from the purifiers. Such condensed
liquid collecting at the bottom of the condenser is removed from time to time
through a suitable waste valve or connection.
For the immediate or direct utilization of the gas thus collected, purified and
dried for recarbonating storage beer, a carbonating device K, of any suitable
construction, is provided. The carbonator is provided with devices for auto-
matically regulating the supply of gas thereto according to the supply and pressure
of beer, and is connected with the gas pipe j' which has a valve and coupling, by a
hose having a valve and coupling at its delivery end for attachment to the
carbonator without admitting air thereto. It is also connected with the force or
discharge pipe I, of a pump L, by a pipe k', which has valves on opposite sides
of its connection with pipe 1 for admitting beer either into the top or bottom of the
carbonator, and a waste cock for discharging air from the carbonator when it is
first filled from the bottom with beer in starting the apparatus. The suction
pipe of the pump L is connected with the storage cask or tank B, and by a
by-passage or pipe having an automatic regulating valve or device ³, with the
force or discharge pipe l, whereby communication is established between the
suction and discharge connections of the pump whenever the pressure on
the discharge side of the pump reaches a certain predetermined point. The pipel
is provided with a reducing valve, by which the supply of beer to the carbonator
is regulated and maintained at a constant pressure. The excess of beer delivered
by the pump is conducted through the by-passage or pipe back to the suction
pipe . From the carbonator the charged beer or other liquid is conducted by a
pipe or hose to a filter M, and thence by a pipe or hose m, to the racking
bench N, where it is drawn into shipping kegs in the usual way.
not required for immediate use it may be conducted from the delivery pipe into
a storage tank, or may be liquefied or compressed in the usual cylinders for storage,
shipment and future use.
When the
gas is
In performing the improved process by means of the apparatus herein before
described, when open fermenting tubs are employed, the hood or bell a of each
tub is first lowered into the tub and with its hose connection a¹ is completely
immersed in the liquid, the valve a² in the hose connection bein opened. Air is
thus completely displaced in the hood and its connections, and when fermentation
actively takes place in the liquid the valve a² in the hose connection is closed and
the hood a is elevated to the position in which it is shown at the left in the upper
tier of tubs.
The system of gas collecting pipes D D' having been first filled with air-free
gas supplied from other fermenting tubs, or any convenient source, the valve d' in
the adjacent hose d is opened, permitting the gas to expel any air that may be

page_text: contained in said hose, which is then coupled to hose a'. The valve a' is now
opened, and as the gas is given off by the liquid it is collected by the bell a and
conducted through the connections above mentioned into pipe D, thence through
pipe D' into the receiver C.
To certainly avoid the collection of air with gas at the outset and to save time
by beginning to collect the gas at the earliest practicable stage of fermentation,
the bell a may be connected with the gas collecting main before it is raised above
the surface of the liquid in the tub, and gas introduced into it from said main as
it is being elevated into operative position. A very low pressure is maintained in
the system of gas-collecting pipes so as not to interfere with fermentation and
impede the separation of gas from the liquid. As soon as the supply of gas from
the liquid is sufficient to overbalance the slight pressure in the gas-collecting
system, it will pass from the bell in which it accumulates, free from air, into the
main and thence through its connections into the gas receiver C. If gas is
collected from the fermenting tubs faster than it is used, it will extend the
receiver and accumulate therein. When the receiver is filled and its bell engages
with the stop, or from any cause the gas pressure rises above the desired
limit, it will open the safety valve d', or if for any reason that fails to operate,
the gas will displace the water column in one or both of the traps d' and g² and
escape until the pressure is reduced to normal, the safety valve d' being set to
open at a lower pressure than that required to displace the water in either of said
traps, thus avoiding objectionable back pressure in the fermenting tubs. With
closed fermenting tubs such as A' A', the vent valves a³ a are left open during
the initial stages of fermentation, and when it is desired to collect gas therefrom,
the valves d³ in pipes d' are opened and gas is admitted from the main into the
gas collecting spaces of the tubs. All traces of air are thus expelled, with more or
less gas, from the gas collecting spaces through the vents a³. As soon as pure
gas issues from the vents they are closed and then the gas produced by fermenta-
tion of the liquid within the tubs accumulates therein until its pressure exceeds
that in the collecting main, whereupon it will flow, free from air, into said main as
long as active fermentation continues, and the connection between said main and
ferimenting tubs is maintained.
The operation of the open fermenting tubs A' is substantially the same as that
of the closed fermenting tubs A. At the outset the gas connection as is coupled
by a hosed with the gas main, and the valve in the air vent connection a' is
opened. All air is thus expelled from the gas collecting space enclosed by the
bell over the surface of the liquid by the inflowing gas, and as soon as substan-
tially pure gas issues therefrom the air vent is closed. The bell being now filled
with pure gas, and air excluded therefrom, the pressure is increased by the
accumulation of gas given off by the fermenting liquid until it overcomes the
pressure maintained in the gas collecting pipes and flows free from air to
the receiver. Gas thus collected from the fermenting tubs may be directly
employed to recarbonate beer or similar beverages taken directly from the storage
casks or tanks. For this purpose the beer is drawn by the pump L from a storage
cask and forced with a regulated pressure through a carbonator, thence to the
racking bench for filling shipping kegs or other receptacles. The necessary supply
of gas for carbonating the beer on its passage from the storage cask to the
racking bench is taken from the receiver C and forced by pump G with a
regulated pressure to the carbonator K. Thus the gas which is given off from
the beer during the process of fermentation is collected and directly re-used for
carbonating beer or other beverages.
A very small percentage of the gas produced by the fermentation of beer and
other similar beverages is needed for recarbonating it, and while the continuous
and direct recarbonating of beer is taking place the surplus gas, may be
accumulated in a receiver for future use, or employed for other purposes.
In practice it is necessary to frequently empty and wash and to occasionally
dry and varnish the fermenting tubs inside. Thus air is unavoidably and

page_text: frequently admitted thereto. For this reason and to avoid interference with
the process of fermentation and interruption of the ordinary operation of a
brewery, it is customary to place the fermenting tubs in different cellars or
apartments and to empty, wash and refill them with wort in rotation or alterna-
tion. In accordance with the usual practice it is to be understood that the
fermenting tubs of the before described apparatus, which are connected with the
several gas-collecting pipes D D, are located in different cellars or apartments, so
that some or all of the tubs in any cellar may be emptied, washed, dried and
varnished without interfering with or interrupting the production and collection:
of gas from tubs in other cellars or apartments.
Since it is customary to brew at frequent intervals, and a single brewing-
ordinarily fills a number of tubs, it follows that the beer in some or all of the
tubs of one or more cellars is always at the proper stage of fermentation or in
condition to yield gas. It is therefore generally desirable to connect a number of
tubs simultaneously with the gas delivery main, and to save the time and trouble
of venting and connecting such tubs separately, the several branch collecting pipes
are provided with air vent valves de de and, close to these, shut off valves d' d
next to the delivery main D'. Air contained in the gas-collecting spaces of any
or all tubs which are connected with any pipe D and are in condition to yield gas,.
is expelled by the gas produced in such tubs through the common vent valve d
while the adjacent valve d' is closed, aud when the effects of diffusion and all
traces of air have been removed and air-free gas issues from said vent, the vent
is closed and all said tubs are simultaneously connected with the main D¹ by
opening the valve d'.
In this way a number of tubs are simultaneously connected with the main in the
same manner as individual tubs without admitting air to gas previously collected
or interrupting the operation of the apparatus.
By the method and means herein before explained of expelling and excluding air
from the fermenting tubs, nearly or quite pure carbonic acid gas is directly
obtained from the fermentation of the liquid contained therein, and this gas may
be advantageously used under ordinary conditions without further purification or
condensation. By positively expelling air from the gas collecting spaces of the..
fermenting tubs by the introduction of pure carbonic acid gas from the main or
some other outside source, gas free from air can be obtained from such tubs much
sooner than it otherwise could be, but by waiting a sufficient length of time for
the gas produced by fermentation to completely displace the air contained in the
collecting spaces of those tubs from which it is desired to collect air-free gas,.
substantially the same result is secured. Although this involves some loss of time
and waste of gas, it is perfectly practicable, particularly in large breweries where
there are constantly available many different fermenting tubs from which gas may
be obtained.
When economy of gas is not essential, the receiver or holder C may be
disconnected for the purpose of repairing or cleansing it or it may be altogether
dispensed with and the gas delivered as it is collected from the fermenting tubs by
the main D' directly to the carbonator or other apparatus.
For the purpose of delivering gas at will to the receiver or directly to
the carbonator or other apparatus, the supply and discharge pipes of the gas.
holder Care provided with valves c2c and connected below by a pipe e provided
with a valve c¹.
By closing the valve c and opening the valves c³, the gas will be caused to pass.
into the gas holder and thence to the carbonator; but by opening the valve c' and
closing the valves the gas will be shut off from the gas holder and caused to pass.
directly from pipe D' to the carbonator.
The hoods of the open fermenting tubs are sufficiently heavy to hold their rims
steadily in place and prevent them from being raised out of the liquid into which
they project by the greatest gas pressure intended to be produced in the gas.
collecting system, and the bell or movable part of the gas receiver or holder Cis

page_text: weighted and arranged so as to maintain or admit of a substantially constant low
pressure in the gas collecting pipes and fermenting tubs.
Many changes in the details of the apparatus may be made without departing
from the spirit and intended scope of the invention.
Having now particularly described and ascertained the nature of this said inven-
tion as communicated to me by my foreign correspondents, and in what manner
the same is to be performed, I declare that what I claim is :"
1. Obtaining free from air the carbonic acid gas generated by fermentation
within a tub or vessel by hermetically-closing, except for an air outlet, a gas-
collecting space or chamber communicating with the tub, ejecting through the air
outlet all the air contained in the chamber as for example by submerging the
chamber in the fermenting liquid or filling it with air-free gas and thereafter
closing the air outlet and conducting from the chamber the gas produced by the
fermenting liquid in the vessel, substantially as described.
2. In the process set forth in the preceding claim, maintaining a pressure within
the chamber in excess of that of the atmosphere so that in case of leakage the
air will not enter the chamber, substantially as described.
3. The herein described operation of carbonating beer, consisting in hermetically
Eealing, except for an air outlet, a gas-collecting space or chamber communicating
with a fermenting tub or vessel, ejecting through the air-outlet all the air contained
in the chamber, closing the air outlet, collecting within the chamber the carbonic
acid gas given off by the fermenting liquid in the vessel, maintaining within the
chamber a pressure in excess of the atmospheric pressure and thereafter with-
drawing the gas from the chamber and delivering it at a higher pressure to the
carbonator, substantially as described.
4. The herein described method of obtaining a constant supply of air-free
carbonic acid gas for the direct and continuous carbonation of beer consisting in
operating a number of tubs or vessels and gas-collecting chambers in the manner
mentioned in the last preceding claim, and connecting them in succession or
alternation with the main or conduit by which the carbonators are supplied,
substantially as described.
5. The direct and continuous process of carbonating beer which consists in the
following steps: First, enclosing and hermetically sealing the fermenting space of
a fermenting vessel with the exception of an air escape, and allowing carbonic
acid gas to accumulate therein until it completely drives out the contained atmo-
spheric air and overcomes the effects of diffusion; second, closing said air vent
and leading the gas thereafter produced to a conduit or receiver; third, drawing a
portion of the gas from the conduit or receiver into the carbonator and utilizing
the same to carbonate beer; fourth, delivering surplus gas from the conduit or
receiver to the similarly enclosed fermenting space of another fermenting vessel to
eliminate atmospheric air therefrom, and thereafter connecting said space with
the conduit or receiver, different fermenting vessels being thus connected in
succession or alternation, whereby a constant supply of air-free gas is delivered
to the carbonator from the fermenting vessels.
6. In apparatus for collecting carbonic acid gas from fermenting liquid, the
combination with the vessel containing the liquid, of a cover or hood, means for
hermetically sealing the cover to the vessel, a valved air-outlet in the cover, a gas
main with valved connections for establishing communication between the main
and the interior of the cover for passing gas either from the main to the vessel
or vice versa, a trap in connection with the main for removing moisture from the
main and a safety valve to relieve or prevent undue pressure in the main,
substantially as described.
7. In apparatus for collecting air-free carbonic acid gas from fermenting
liquids, the combination with a number of vessels containing the liquid and each
arranged and connected as set forth in the last preceding claim, of a gas holder
substantially as and for the purpose described.

page_text: 8. In apparatus for carbonating liquids, the combination with apparatus such as
set forth in the last preceding claim, of a carbonator, a pump interposed between
the gas-holder and carbonator and a second pump communicating with the liquid
reservoir and the carbonator, and with or without a filter and racking faucet, all
operating substantially as and for the purpose described and illustrated in the
accompanying drawings.
9. A complete plant for collecting and utilizing carbonic acid gas constructed
and operating substantially as described and illustrated in the accompanying
drawing or with the fermenting tubs or vessels constructed all according to any
one or two of the modes shown in the drawing.
Dated this 11th day of February 1896.
BOULT & WADE,
Agents for the Applicant.