WO2009012554A1

WO2009012554A1 - Fluid cyclon filter

Info

Publication number: WO2009012554A1
Application number: PCT/CA2007/001299
Authority: WO
Inventors: Robert Petroff; Todor Givechev
Original assignee: Robert Petroff; Todor Givechev
Priority date: 2007-07-20
Filing date: 2007-07-20
Publication date: 2009-01-29

Abstract

Disclosed is a filter comprising a housing defining: a first chamber, a second chamber ringed by the first chamber, a third chamber ringed by the second chamber, second openings leading between the first and second chambers, and a third opening leading between the second and third chambers. In use, liquid in the second chamber submerges the second openings such that a gas/particle stream entering the first chamber travels helically therethrough and at the second openings turns into bubbles. As the bubbles traverse the liquid, some particles become entrained therein and others become wetted, whereby gas, particles and wetted particles breach the liquid, helically travel through the second chamber and exit via the third opening to produce a cyclone in the third chamber. Particles and wetted particles descend along the periphery of the third chamber for egress through a lower opening. A filtered stream issues through an upper opening.

Description

FLUID CYCLON FILTER

FIELD OF INVENTION

The present invention relates to the removal of contaminants from air or other gases.

DESCRIPTION OF THE RELATED ART

There are many known filters wherein contaminated/polluted gas is passed through filtering elements, nets, etc. to remove particulate matter. These filters can work well. However, these filters can be relatively costly and inconvenient to use, since optimal performance often requires relatively frequent replacement of the filtration media.

There are also filters wherein the gas to be cleaned is passed through a cyclone and particles entrained therein are removed as a result of centrifugal forces. These filters, lacking filtration media, can be relatively convenient and inexpensive to use. However, cyclonic filtration works best with relatively larger particles. Known cyclonic filters capable of removing bacterial contaminants or other fine, dust-like particles are relatively complex and costly.

It is also known to pass polluted gases through a fluid, particularly through water, so that contaminants are wetted and separated from the cleaned air/gas. These filters can be relatively convenient and inexpensive to use. However, known filters of this type again work best with relatively larger particles. Relatively inexpensive filters of this type are known, but these are not particularly effective in the removal of bacterial contaminants or other fine, dust-like particles.

SUMMARY OF THE INVENTION

The invention relates to a filter apparatus. The apparatus comprises a housing which defines, in use: an annular first chamber orientated co-axially with a vertical, longitudinal axis; an annular second chamber orientated substantially co-axially within

- l - the first chamber; a third chamber ringed by the second chamber; at least one first opening leading into the first chamber; a plurality of second openings leading from a lower part of the first chamber into a lower part of the second chamber; at least one third opening leading from an upper part of the second chamber into an upper part of the third chamber; an upper opening leading out of the upper part of the third chamber; and a lower opening leading out of the lower part of the third chamber. In use, the second chamber contains liquid sufficient to substantially submerge the second openings such that, if a mixed stream of gas and particles is caused to enter the first chamber via the at least one first opening, the mixed stream travels in a helical manner through the first chamber and exits the first chamber via the second openings. As it traverses the second openings, the mixed stream of gas and particles turns into a stream of bubbles in the liquid. As the bubbles traverse the liquid, a portion of the particles become entrained in the liquid and a further portion of the particles become wetted, such that a partially filtered stream of gas, particles and wetted particles breaches the liquid. The partially filtered stream travels in a helical manner through the second chamber and exits the second chamber via the third opening. The partially filtered stream entering the third chamber produces a cyclone, such that a portion of the particles and wetted particles thereof descend along the periphery of the third chamber for evacuation through the lower opening thereof, leaving a filtered gas stream to issue through the upper opening. The filter is relatively convenient and inexpensive to use, relatively inexpensive to construct and has relatively good efficiency in the removal of particulate matter including bacterial contaminants and other fine, dust-like particles.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described below with reference to the accompanying drawings, in which:

Fig. 1 is a vertical, partially schematic, cross section of the filter showing the starting condition of the apparatus before operation commences; 85

Fig.2 is a vertical cross section of the filter of Fig. 1 in use;

Fig.3.1 is a view along section A-A of Fig. 2;

90 Fig.3.2 is a view along section B-B of Fig. 2;

Fig.3.3 is a view along section C-C of Fig. 2; and

Fig.4 is a horizontal cross section of a filter according to another 95 example of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 illustrates a filter device including a housing 20. The ioo housing 20 comprises a cylindrical main vessel 1, a lid 2 incorporating an exhaust pipe 3 defining an upper opening 28 and a particle disperser cone 4, a secondary cylindrical vessel 5, and a third cone-shaped vessel 6. Seals 7 are installed between the housing components to provide air-tight seals such that:

105 vessel 6 and lid 2 define a third chamber 26 having a vertical, longitudinal axis X-X; vessel 6, vessel 5 and lid 2 define an annular second chamber 24 orientated substantially co-axially with and ringing the third chamber 26; and vessel 1 and vessel 5 define an annular first chamber 22 orientated substantially co- lio axially with and ringing the second chamber 24. The main cylindrical vessel 1 has one tangential first inlet opening 8 for the air/gas to be cleaned to enter the first chamber 22. In the inlet 8, when the filter is used for dust cleaning, a diffuser nozzle 13 shown in Fig. 3 is installed that primarily wets the entering

115 particles to improve the cleaning action.

The secondary vessel 5 features at its lower end circumference multiple turbine-like second openings 9 through which the air/gas to be 120 cleaned enters into the fluid 10, usually water, in the secondary vessel 5.

The third cone shaped vessel 6 has at its upper circumference a tangential, turbine-like third opening 11 through which the air/gas enters and a small lower opening 12 at the lower end. 125

In use, polluted air/gas to be cleaned is introduced through the tangential inlet 8 at a pressure sufficient to push the liquid IO through the turbine-like openings 9 of the vessel 5 until the liquid level in first chamber 22 is below the level of the openings 9.

130

At this point, polluted air/gas from the first chamber 22 starts to enter the second chamber via openings 9. Objects in the flow larger than the openings 9 are restrained and do not pass into the second chamber 24. As well, other large, relatively dense 135 particles that may be contained in the polluted air/gas flow tend to settle, and will also remain in the first chamber 22.

The air/gas from chamber 22 which enters the liquid 10 via openings 9 drives the fluids inside the second chamber 24 in a 140 circular motion and passes through the liquid 10 in the form of bubbles. As the bubbles traverse the liquid, a portion of any particulate matter therein becomes entrained in the liquid and a further portion becomes wetted, such that a partially filtered stream of gas, particles and wetted particles breaches the liquid.

145

The now partially-filtered stream enters through opening 11 into the third chamber 26 defined by conical vessel 6. Under the influence of the centrifugal forces of an air/gas cyclone created in vessel 6, much of the remaining particles and wetted particles 150 are thrown to the inner sidewall of the vessel 6 and descend down to its lower end opening 12 for evacuation. The cleaned air/gas leaves the filter through the exhaust pipe 3.

This apparatus, when filled with 5% NaOH solution, was coupled 155 to the exhaust pipes of four 2OL Applikon bioreactors in which Escherichia coli K12 bacteria had been cultivated. The bacterial concentration in the off-gas leaving and entering the apparatus was 70%. The airflow in the system was 60L/min. Petri dishes were exposed to the gas leaving the apparatus after filtration by 160 placing them in baskets hanging in the exhaust pipe of the bioreactors. After 36 hours of operation at 75% humidity and a 36⁰C, there was no detectable growth of Escherichia coli bacteria in the control Petri dishes. 165 Fig. 4 shows a cross-sectional view of apparatus according to the invention having eight second openings 9. In this apparatus,

Diameter a = 6 cm

Diameter b = 6 cm

170 Height C = 120 cm

Diameter d = .5 cm

Diameter e = 22 cm

Diameter f = 32 cm

175 This apparatus, when filled with 14 litres of water, and driven at a pressure differential of 20 mm Hg, removed bacterial contaminates from a gas flow of 60 L/min such that the exhaust gas appeared contamination free after examination. Without intending to be bound by theory, it is believed that such

180 effectiveness derived from the relatively small bubbles formed in use. The small bubble size flowed, at least in part, from a phenomenon which was observed in use, to wit, the bubbles that periodically issued from each of the second openings 9 were observed to impact upon and be broken by the bubble formed on

185 the neighbouring turbine opening 9.

After extended use, the housing can be dismantled, washed and reassembled.

190 Whereas but two embodiments of the invention are described and illustrated, it will be understood that variations therein can be made.

Indeed, it should be emphasized that the size of the various chambers, and number and size of the various openings, are

195 required to be varied to account, inter alia, for the operating pressure, gas throughput and contaminant make-up. After a review of this disclosure, this variance will be a manner of routine to persons of ordinary skill in the art, and as such, is not described herein in detail. As well, whereas vessel 5 is

200 cylindrical, it could be frustoconical, as could vessel 1. Indeed, the various vessels need not be entirely round, and could take shapes other than cylindrical and frustoconical. As well, greater or lesser number of first, second and third openings could be provided than those numbers set forth herein. As well, the 205 diffuser nozzle can be omitted. Additionally, more vessels could be utilized, and the housing could be constructed, for example, out of permanently welded components. Yet further, whereas the removal of particulate matter is discussed, it will be evident that this structure could also have utility in the context of the removal

210 of gaseous contaminants that are soluble in the liquid used. Moreover, it should be understood that the apparatus could be used with a pressurized fluid applied to inlet 8, or with a vacuum applied outlet 3, or a combination thereof.

215 In view of the above, the invention should be understood as limited only by the appended claims, purposively construed.

Claims

1. A filter apparatus comprising: a housing which defines, in

220 use: an annular first chamber orientated co-axially with a vertical, longitudinal axis; an annular second chamber orientated substantially co-axially within the first chamber; a third chamber ringed by the second chamber; at least one first opening leading into the first chamber; a plurality of second openings leading

225 from a lower part of the first chamber into a lower part of the second chamber; at least one third opening leading from an upper part of the second chamber into an upper part of the third chamber; an upper opening leading out of the upper part of the third chamber; and a lower opening leading out of the lower part

230 of the third chamber, wherein, in use, the second chamber contains liquid sufficient to substantially submerge the second openings such that, if a mixed stream of gas and particles is caused to enter the first chamber via the at least one first opening: the mixed stream travels in a helical manner through

235 the first chamber and exits the first chamber via the second openings, the mixed stream of gas and particles turns into a stream of bubbles as it traverses the second openings; the bubbles traverse the liquid; as the bubbles traverse the liquid, a portion of the particles become entrained in the liquid and a

240 further portion of the particles become wetted, such that a partially filtered stream of gas, particles and wetted particles breaches the liquid, the partially filtered stream travelling in a helical manner through the second chamber and exits the second chamber via the third opening; the partially-filtered stream

245 entering the third chamber produces a cyclone, such that a portion of the particles and wetted particles thereof descend along the outer periphery of the third chamber for evacuation through the lower opening thereof, leaving a filtered stream to issue through the upper opening.

250 2. A filter apparatus according to claim 1, wherein the third chamber is frustoconical and tapers towards the lower opening.

3. A filter apparatus according to claim 2, wherein the second chamber is cylindrical.

255

4. A filter apparatus according to claim 3, wherein the first chamber is cylindrical.

5. A filter apparatus according to claim 4, wherein the third 260 opening is tangential to the third chamber.

6. A filter apparatus according to claim 5, wherein the second openings are tangential to the second chamber.

265 7. A filter apparatus according to claim 6, wherein the first opening is tangential to the first chamber.

8. A filter apparatus according to claim 1, wherein the housing is adapted to be dismantled, washed and reassembled.

270

9. A filter apparatus according to claim 1, further comprising a nozzle adapted to wet the gas stream entering the first chamber.