CA1042362A

CA1042362A - Apparatus with foam breaker

Info

Publication number: CA1042362A
Application number: CA226,166A
Authority: CA
Inventors: Hans Muller
Original assignee: Process Engineering Co SA
Current assignee: Process Engineering Co SA
Priority date: 1974-05-13
Filing date: 1975-05-02
Publication date: 1978-11-14
Also published as: FR2270919B1; GB1482291A; DE2518082C3; DD118118A6; ATA360075A; DE2518082A1; CS188954B2; AT341469B; JPS50144099U; JPS5639359Y2; DE2518082B2; FR2270919A1

Abstract

ABSTRACT OF THE DISCLOSURE
Foam is generated in a vessel as a result of the mixing of gaseous and liquid phases in the vessel. A foam breaker has a housing which straddles and is open to an upper opening of the ves-sel. A vertical shaft is mounted in the housing for rotation by an upper and a lower bearing; the shaft carries conical foam break-ing members and the housing has an outlet through which the gaseous component of the broken-up foam can escape.

Description

This application i5 directed to an apparatus wherein foam is generated as a result of the opera~ion of the apparatu~, and whihh is provided with an improved foam breaking arrangement.
The invention is particularly useul in the continuous, foam-free discharge of gaseous reaction products from fermenters, i.e., from vessels wherein micro-biological reactions take p~ace which generate such gaseous reaction products.
Equipmant of this ~ype, provided with fo~m breaking ar-rangem~ats, is already known in ~he art, e.g., from U.S. Patents 0 ~08. 3,693,325 and 3,501,414. In these basically sati~factory con-structions of the prior art the foam breakers are located in the reactor vessel itself. This means that when certain dimensions of ~he reactor vessel and foam breaking arrangement are exceeded, it is difficult to satisfactorily ~ournal the rotary shaft of the ar-rangement, in such a manner as to prevent it from performing '~hip-ping" motions and undergoing excessive vibrations during its rota-tion.
It is therefore an ob~ect of this invention to further improve foam braaking arrangements in appratus of the type outlined above.
More particularly, it is an object of this invention to provide auch an apparatus where the aforementioned problems are ov-ercome and do not impose any limitations on ~he size of ~he appara-tus and/or its output càpability per unit time.
Another ob~ect iB to provide a foam breaker arrangement which is simple and which can be used with differently sized react-or vessels.
In keeping with these ob~ect9, and with others which will become apparent hereafter, a feature of the invention resides in an apparatus in which mixing of gaseous and liquid phases results

- 2 -104;~36~:
in the formation of foam. Briefly stated, the apparatus comprises a) a vessel in which ~he foam is formed, said vessel having an opening; and b) foam-breaking means for breaking up ~he foam into its constitu-ent liquid and gaseous components, comprising a housing stradd-ling said opening and communicating through the same with said vessel, a shaft extending in the interior of said housing, foam breakers aarried by said shaft within said housing, bearings journallinæ said shaft at axiaLly spaced locations for rotation about the longitudinal axis of said shaft, and a drive for ro-tating said shaft abou~ said axisO
The novel features which are considered as charac~eristic : for the invention are set forth in particular in the appended claims.
The invention i~self, however, both as to its const~uction and its ~ method of operation, together with additional objects and :.a~.vant-.~Z ages thereof, will be best understood from the following description of ~pecific embodiments when read in connection with the accomæany-:~ ing dra~ingO
The single FIGURE is a fragmentary vertical section ~ 20 through an exemplary embodiment of the inventionO
: Reference numbra~ 2 identifies an upright fermenter or, generally, reactor vessel of the type disclosed in the aforemention-ed UOS. patents. Of course, the vessel 2 could also have a more or less horizontal orientation, if desiredO It will, in any case, have an opening 2a which may be bounded by a flange 2bo According to the invention, the foam breaking arrangement has a housing 1 which is mounted on the vessel, e.g., by means of flange la that cooperates ~lth flange 2b These flanges may be ,~
bolted or otherwi~e secured together, as known in the art~

Mounted in the upright housing 1 is an upright shaft 3

- 3 -which is journalled for rotation in an upper antifriction hearing 7 and a lower anti-friction bearing 6. In the illustrated embodi-ment the upper bearing 7 is mounted on housing 1, whereas lower bearing 6 is carried by vessel 2. However, both bearings could be carried by housing 1, if desired.
A lower part of shaft is constructed as a hollow shaft section 5 which is provided in its circumferential wall with open-ings or perforations 5a. For this purpose, the solid shaft may be surrounded with clearance by a perforated sleeve which is mounted on it by means of supporting struts or the like. The upper part of shaft 3 extends out of the housing 1 and carries a belt pulley 3a. An electric motor 9 is stationarily mounted adjacent the hous-ing 1 (it might even be mounted on the same) and has an output shaft which also carries a belt pulley 9a. A drive helt is trained around the pulleys 9a, 3a and rotates shaft 3 when motor 9 is energized.
The shaft section 5 has mounted on it upwardly convergent annular foam-breaking members 4 which are so arranged that they axially overlap one another. The members 4 rotate with shaft 3, 5.
Mounted on the inside of housing 1, exten~ing over the entire axial height of the members 4 but outwardly spaced from them, are stationary baffles 10, also known as "chisanes". They prevent a smooth circulation o foam, causing turbulence which forces the foam to enter between the members 4 and to become separated into its constituent liquid and gaseous components, in the manner disclos-ed in the aforementioned U.S. patents.
In operation, dense foam develops in vessel 2 due to the mixing of air (which is blown into the vessel 2 in known manner) with the fermentation liquid (e.g., nutrient medium) and the reac-tion gases which are metabolically generated by the growing micro-organisms. This foam must be separated into its liquid component ' 104Z~6Z

that is to be retained in the vessel 2, and its gaseous component(air and reaction product) which are to be vented from vessel 2.
The foam rises through opening 2a into housing 1 and is separated into its constituent components by the rotating members 4. The liquid component is flung against the baffles 10 and runs back into the vessel 2, whereas the gaseous component escapes through the open-ings 5a into the interior of the section 5 and travels upwardly therein to escape through the outlet 11 which is provided in the housing 1 for this purpose.
It will be understood that each of the elements descri~ed above, or two or more together, may also find a useful application in other types of construction differing from the types descrihed above.
While the invention has been illustrated and described as embodied in a foam-breaker, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an apparatus in which mixing of gaseous and liquid phases results in the formation of foam, a combination comprising a vessel in which the foam is formed, said vessel having an opening;
and foam-breaking means for breaking up the foam into its constitu-ent liquid and gaseous components, comprising a housing straddling said opening and communicating through the same with said vessel, a shaft extending in the interior of said housing, foam breakers carried by said shaft within said housing, bearings, journalling said shaft at axially spaced locations for rotation about the long-itudinal axis of said shaft, and a drive for rotating said shaft about said axis.

2. A combination as defined in claim 1, wherein said housing and shaft have an upright orientation, and wherein said bearings comprise an upper bearing and a lower bearing.

3. A combination as defined in claim 2, wherein said low-er bearing is carried by said vessel.

4. A combination as defined in claim 2, wherein said up-per bearing is carried by said housing.

5. A combination as defined in claim 4, said housing hav-ing an upper and, and said upper bearing being mounted at said upper ent.

6. A combination as defined in claim 1, wherein said foam breakers are annular members mounted on and surrounding said shaft.

7. A combination as defined in claim 1, wherein said foam breakers are upwardly convergent coaxial members mounted on said shaft and surrounding the same at axially adjacent locations, adjacent ones of said members axially overlapping one another.

8. A combination as defined in claim 1, wherein at least a portion of said shaft is hollow and perforated; said housing having an upper end portion provided with an outlet for the gaseous component of the broken-up foam.

9. A combination as defined in claim 6, and further comprising stationary baffles mounted in said housing outwardly adjacent said annular members.