CA1136541A - Gas purifying filter - Google Patents

Abstract

GAS PURIFYING FILTER
ABSTRACT OF THE DISCLOSURE
A gas purifying filter comprises a housing provided with gas inlet and outlet stubs arranged on side walls thereof. Rigidly secured inside the housing are stationa-ry filtering elements fabricated from fibrous chemisorb-ing material in the form of rectangular plates disposed vertically and arranged essentially in parallel with one another. Opposite side edges of the rectangular plates are connected therebetween in pairs by partitions so as to af-ford an opening for the passage of gas between the plates facing the partition connecting the side edges of a pair of plates. Mounted above the rectangular plates are liquid compartments, the liquid serving to regenerate the filtering elements and being in contact with the upper section of the plates.

Description

Title of the Invention GAS PURIFYING FILTER
Field of the Invention ~ he present invention relates to aPparatus for se-parating chemically active gaseous substances ~rom gases containing the same, and more particularly to gas puri-~ying filters.
The herein proposed device can be utilized in the metallurgical, machine-building, power-generating and other branches o~ industry at plants engaged in process-ing, manufacture, storage o~ chemicals and in other tech-nological operations, in the course o~ which toxic gases are liable to emanate into enclosed spaces and surrounding atmosphere, as well as for sanitary purification of the forced, exhaust and recirculating ventilation air and waste gas.
Background of the Invention Inherent in the plants of various branc~es of in-dustry wherein it is practically impossible to eliminate the escape of to2ic gases into enclosed working spaces and surrounding atmosphere from the plant machinery lack-ing complete gas-tightness is a problem o~ sanitary puri-fication of the centralized gas flows through separating toxic gaseous constituents there~rom. Problems like this one can be solved through improved working conditions ~or the employees, preventio~ of corrosion of the special-pur-pose equipment, particularly t~e costly electronic ~low-process control devices, and reduction of the environment-~. , 113~541 al pollution. These problems tend to become more acute withtime due to a general increase in the industrial production, more rigid sanitary regulations for industrial gas wastes and for toxic constituents in enclosed spaces of plants.
Since it is impossible to find a drastic approach to the problem of ensuring absolute gas-tightness of the eguipment or complete automation o~ the technological processes, a most practicable way of extracting toxic constituent from the ambient air is the purification of the centralized gas flows by means of various equipment arrangements and ~low dia~rams~ enabling to reduce to a certain degree the level of the gas stream co~tamination by toxic constituents and to subsequently utilize the substances withdrawn therefrom.
'l'he known constructions of filters for separating toxic constituents from gases containing the same feature remov-able riltering elements (such as cellular, cartridge, sleeve, ~oldable, frame and bag filtering elements) adapted to ad-sorb the toxic constituents to be thereafter extracted from the body of the rilter and regenerated in 2 separa~e unit.
Regeneration is ef~ected by chemisorbtion of the toxic con-stituents or by replacing used elements ~y ~resh non-rege-nerable sorbents. Special supports and seals Yor filter-ing elements intended to increase gas-tightness and struc-tural rigidity of apparatus make replacement of the ele-ments a labour-consuming operation which, in turn, leads to limited application of such ~ilters rOr gas purifica-tio~.
Known in the art is an apparatus for continuous re-113654iL

moval of gases (cf. U.S. Patent No. 3,498,026, Cl. 55-73, published 1970) comprising a housing having inlet and out-let openings ~or the passage o~ ambient air. The housing is partitioned into an upper and lower chambers. l`he lower chamber located below the air inlet opening contains a self-sustaining liquid tank unit. Accomodated essentiall~
vertically relative to the housing and inside thereof is a wide movable endle~s belt, i.e. the filtering element, ~abricated from a fibrous chemisorbing material capable o~
adsorbin~ unwanted constituents o~ the ambient air ilow, said belt being suspended and guided by a plurality of rol-lers mounted within the housing on the top and bottom walls thereof. A section o~ the beit in the upper chamber screens the air inlet providing thereby the removal of unwanted gases. In the lower chamber saturated with unwanted gases a section of the ribrous chemisorbing belt passes through the liquid tank (e.g., hot water) wherein removal o~ the adsOrbed substances and regeneration of the belt material takes place.
q`he heretofore described apparatus ~eatures inef~i-cient utilization of the interior space by chemisorbing material because the ~iltering element proper is a single c~emisorbing belt acting to screen a narrow cross-sectional portion of the apparatus. l'his substantially reduces spe-cific adsorption of the toxic gases relative to the per unit volume of the apparatus. Also, the apparat~s features low ratio between the volume of the chemisorbing material proper and the volume o~ the regenerating liquid, since in ~136541 the course of operation the moving chemisorbing belt must be completely immersed into the regenerating liquid tank with sufficient dwell time for contact between the belt and the liquid. This results in an increased specific con-sumption of the regenerating liquid and low concentration of contami~ating substances released thereinto after said liquid leaves the regenerating chamber, which complicates subsequent utilization thereof.
In addition, it is difficult to achieve gas-tight-ness in various portions of the apparatus with a wide belt continuousl~ moving between the upper and lower chambers, which have different operating conditions.
Also known is an ionic filter for separating agres-sive substances ~rom gases (cf. USSR Inventor's Certifi-cate No. 507,334, Cl. B 01 d 23/04, published 197~) com-prising a housing having openings for inlet of contaminated gas and discharge o~ the purified gas arranged essentially on the side walls thereoY. Rigidly secured inside the hous-ing is a stationary filtering element in the form o~ a sleeve fabricated ~rom an ion-exchangable ~ibrous material and mounted with the open end thereof on the inlet opening ~or the contaminated gas. Arranged at the bottom of the housing is a liquid tank, the liquid acting to regenerate the filtering element. & closed end of the sleeve is secur-ed to the bottom of the tank. In the course o~ gas purifi-cation in the filter, said tank contains no liquid acting to regenerate the filtering element and under combined ac-tion of the weight of the tan~ and a float the ion-exchang-able ~ibrous sleeve remains in a stretched state. Upon sa-turation of the ion.exchangable ~ibrous material with to-xic gases, the gas inlet opening is closed by a gate so as to prevent the ~low o~ gas through the filter. There-a~ter, a regenerating liquid is fed into the lower portion of the housing until the tank and the ~loat are raised to a selected height whereat the sleeve is completely immersed into the regenerating liquid. A~ter a certain dwell time the liquid is arained out of the tank and the filter is ready ~or rurther puriIication.
Owing to the fact that the riltering element is in the form o~ a sleeve completely immersible into the rege-nerating liquid, said rilter features low ~illability o~
the ~ilter volume with the chemisorbing material resulting in a reduced speci~ic adsorption of the toxic gases per unit volume o~ the filter and in an increased speci~ic consumption of the regenerating liquid during a single cgcle. Furthermore, the operating mode o~ the hereto~ore described filter is inherently noncontinuous, requiring to completely discontinue the operation thereo~ for rege-neration of the contaminated ~iltering element.
Summary of the Invention It is there~ore an object o~ the present invention to provide a gas puri~ying ~ilter, ~hich would a~ord to increase speci~ic adsorption o~ the toxic gases per unit volume thereo~ and to reduce specific consumption of the li~uid acting to Iegenerate the ~iltering elements.
Another object of the present invention is to provide -113~i5 a gas purifying ~ilter capable of continuous puri~ication o~ gases without disco~necting the rilter from the gas ~low ~or a period required to ef~ect regeneration of the ~iltering elements.
~ hese objects are attained b~ that in a gas puri~-ing ~ilter, com~rising a housing provided with gas inlet and outlet stubs arranged on side walls o~ the housing, stationary ~iltering elements fabricated from ~ibrous che-misorbing material rigidlg secured inside the housing, and liquid compartments for regenerating the ~iltering elements, the latter being in contact with the liquid, according to the invention, the stationary filtering ele-ments are in the ~orm of rectangular plates positioned vertically inside the housing and arranged in parallel with one another with opposite side edges thereof facing the gas inlet and outlet stubs are connected therebetween in pairs by partitions in such a manner that an opening is formed be~ween the plates ~or the passage of gas ~acing the partition connecting the edges of a pair o~ plates, whereas the liquid compartments are arranged above the plates, the upper sections thereof being in contact with the liquid.
Pre~erably, the liquid compartments serving to rege-nerate the ~iltering elements should be in the form of grooves mounted on the partitions connecting the upper sec-tions of the p7ates, the upper edges o~ the plates being ~olded and the ends thereof lowered into the grooves.
It is also preferable that in order to assure reli-1136S4~

able contact o~ the liquid serving to regenerate the filt-ering elements with the fibrous material thereof, the com-partmen's be in the form of pipes mounted on the partitions connecting the upper sections of the plates and having in the walls thereof adjoining the surface of the plates holes for feeding the liquid directly to the plate surface.
Utilization of the herein proposed gas purifyiQg filter incorporating ~ibrous chemisorbi~ material af~ords to increase speci~ic adsorption of to2ic gases per unit volume o~ the ~ilter owing to the employment o~ a great number of the ~ibrous chemisorbing filtering elements ar-ranged to ~ully occupy the inner volume o~ the rilter hous-ing and also to reduce specific consumption of the regene-rating liquid, since the liquid is introduced into and trickles down exclusively along the material of the filter-ing elements. Also, the gas purifying filter provides a continuous purification process.
Brie~ Description o~ the Drawings ~ he heretofore disclosed objects and advantages of the present invention will be readily apparent ~rom a more detailed description o~ the gas puri~ying ~ilter and pre-~erred embodiments thereof taken in conjunction with the accompanying drawings, in which:
~ ig. 1 is a general view o~ a gas purifying filter (a top plan view with a partial cross-section and partial-ly cut-away wall of the housing), according to the inven-tion;
Fig. 2 is a general view of a gas puri~ying filter 1~3~i541 comprising liquid compartments in the form o~ grooves for regenerating the filtering elements (a front view with partially cut-awa~ wall of the housing on the side of the gas inlet stub), according to the invention; and Fig. 3 is a general view of a gas purifying filter comprising liquid compartments in the form of pipes for re~enerating the filtering elements (a front view with partially cut-away wall of the housing on the side of the gas inlet stub), according to the invention.
Detailed Description of the Invention ~ he proposed gas purifyi~g filter comprises a hous-ing 1 (Fig. 1) having a gas inlet stub 2 and a gas outlet stub 3, both o~ which are arranged on side walls o~ the housing 1. Rigidly secured inside the housing 1 between the walls thereo~ are stationary ~iltering elements in the form of rectangular plates 4. The plates 4 are arranged vertically in the housing 1 and are fixed in parallel with one another. The rectangular plates 4 are fabricated from a fibrous chemisorbing material capable to che~ically ad-sorb the toxic constituents from a gas flow and exhibiting sufricient hydrofilic capacity to swell in a liquid acting to regenerate the filtering elements.
Opposite side edges 5 of the plates 4 facing the stubs 2 and 3 for inlet and outlet of the gas flow are connected therebetween in pairs by partitions 6 so as to provide an opening between the plates 4 for the passage oY gas opposite the partition 6 connecting the edges 5 of one pair of the plates 4. This connection of the side 113~i541 edges 5 of the plates 4 by the partitions 6 de~ines alter-nating inlet chambers 7 and outlet chambers 8 for the pas-sage of gas.
The gas purifying filter also comprises a detachable side cover 9 and a detachable upper cover 10. Arranged in the upper portion o~ the housing 1 is a pipe 11 ~or ~eed-ing a liquid acting to regenerate the riltering elements, said pipe being connected to an external water supply so-urce 12. ~he lower portion of the housing 1 incorporates a pipe 13 (Fig. 2) for draining the regenerating liquid.
Contact of the regenerating liquid with the plates 4 in a iree space of the housing 1 essentially underlying the upper cover 10 is facilitated by that upper sections 14 of the plates 4 are interconnected by partitions 15 with regenerating liquid compartments being arranged above said partitions. These compartments are in the ~orm o~
grooves 16 underlying distributors 1'~, said distributors co~municating with the pipe 11 serving to feed the regene-rating liquid from the external sup~ly source 12. ~he upper sections 14 o~ the plates 4 are rolded so as to have ends 18 t~ereof lowered into the grooves 16.
In another preferred embodiment of the regenerating liquid compartments, the latter are fabricated in the form o~ rectangular pipes 19 (~ig. 3) mounted on the partitions 15 adapted to connect the u~per sections of the plates 4.
~ide walls 20 o~ the rectangular pipes 19 are provided with a plurality o~ hoies 21 serving to reed the regenera-ting liquid directly to the plates 4. The rectangular pipes ~1365~1 19 communicate with the distributors 17 extending from the pipe 11 intended to feed the regenerating liquid from the e~ternal supply source 12.
The gas purifyi~g filter operates as follows.
Air, containing toxic gaseous constituents, is ad-mitted through the gas inlet stub 2 (Fig. 1) into the housing 1 and consequently enters the inlet chambers 7 formed b~ pairs of the fibrous chemisorbing plates 4, the side edges 5 of which facing the gas inlet stub 2 are not connected by the partitions 6. The incoming air is then filtered through the chemisorbing material oi the plates 4 with the result that the toxic gaseous constituents contained therein are chemically adsorbed by the chemisorb-ing material of the plates 4. The thus purified gas flows into the outlet chambers 8 formed by pairs of plates 4, the side edges 5 of which facing the ~as outlet stub 3 are not connected by the partitions 6, and further passes thro-ugh the gas outlet stub 3.
As the chemisorbing material of the plates 4 is sa-turated with the toxic gaseous constituents, regeneration of the riltering elements, i.e. the plates 4, is effected by either disconnecting the filter from the gas flow or without disconnection thereof. In an embodiment of the pre-sent invention, wherein the regenerating liquid compart-ments are in the form of the grooves 16 (Fig. 2), the re-generating liquid is fed from the external supply source 12 via the pipe 11 into the distributors 17 arranged with the open ends thereor substantiall~ overlying the grooves 113~541 16. The regenerating liquid is drawn out of the grooves 16 through upper ends 18 of the plates 4 by virtue of ca-pillary attraction property of the fibrous chemisorbing material of the plates 4 and tric~les down the fibrous ~aterial of the ~lates 4 to be thereafter removed from the housing 1 through the drai~ pipe 1~. In another embo-di~ent of the present invention, wherein the regenerating liquid compartments are in the ~orm of rectangular pipes 19 (Fig. ~), the regenerating liquid is fed from the exter-nal supply source 12 via the pipe 11 and the distributors 17 into the rectangular pipes 19 wherefrom it ~urther pass-es through the holes 21 arranged in the side walls 20 of the pipes 19 and enters the chemisorbing material of the plates 4 trickling ~own therealong to be subsequently re-moved ~rom the housing 1 through the drain pipe 13.
Thus, the herein proposed apparatus ror purirying gases af~ords to increase the utilization of useful filter volume occupied by the plates of fibrous chemisorbing ma-terial and thereby to increase te~fold the specific ad-sorption of toxic gases per unit volume of the rilt~r, as well as to reduce 4 to 5 times the specific consumption Or the regenerating liquid and to provide a continuous operation of the rilter without resorting to the ~iscon-nection t~lereof from a gas flow-for a period required for regenerating the filtering elements.

Claims (3)

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

1. A gas purifying filter, comprising:
a housing;
a gas inlet stub arranged on a side wall of the ho-using;
a gas outlet stub arranged on a side wall of the housing;
stationary filtering elements fabricated from fibro-us chemisorbing material in the form of rectangular plates rigidly secured inside said body, positioned vertically and arranged in parallel with one another, and having side edges and upper sections;
a first plurality of partitions connecting in pairs said side edges of said rectangular plates therebet-ween so as to provide an opening for the passage of gas between the plates essentially opposite the par-tition connecting said side edges of a pair of said rectangular plates; and liquid compartments overlying said rectangular plates, the liquid serving to regenerate said stationary fil-tering elements and to contact with said upper sec-tions of said rectangular plates.

2. A gas purifying filter as defined in claim 1, com-prising:
a second plurality of partitions interconnecting said upper sections of said rectangular plates;
said liquid compartments in the form of grooves mo-unted on said partitions of said second plurality, the liquid serving to regenerate said stationary filtering elements; and said upper sections of the rectangular plates having the ends thereof folded and lowered into said grooves.

3, A gas purifying filter as defined in claim 1, comprising:
a second plurality of partitions interconnecting said upper sections of said rectangular plates; said liquid compartments in the form of pipes mounted on said partitions of said second plurality, the pipes being mounted on said partitions of said second plurality and having walls adjoining the surface of said rectangular plates, the liquid serving to regenerate said stationary filtering elements;
and a plurality of holes arranged in said walls of the pipes serving to feed the regenerating liquid directly to the surface of said rectangular pipes.