Chemistry of inorganic compounds – Modifying or removing component of normally gaseous mixture
Reexamination Certificate
2001-04-12
2003-09-30
Silverman, Stanley S. (Department: 1754)
Chemistry of inorganic compounds
Modifying or removing component of normally gaseous mixture
C423S215500, C422S122000, C422S123000, C422S168000, C422S177000, C422S178000, C095S214000, C095S215000, C095S216000, C095S268000, C095S270000, C095S277000, C095S278000, C095S282000, C095S285000, C055S301000, C055S304000
Reexamination Certificate
active
06627166
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns the field of filtering gases including air. The applications of these devices are multiple: suction devices for household or industrial tasks, air filtering for surgical or industrial clean rooms, air purification for forced ventilation or air-conditioning.
2. Description of the Prior Art
In the prior art, filtering devices are basically constituted by mechanical systems including at least one microporous filter separating the solid particles from the gas medium.
The patents DE8905182, GB2279271 and GB1356866 describe units of conventional filters using filter washing means for the purpose of lubrication.
The patent GB1303250 concerns a filtering unit whose method for capturing particles differs from the invention. The capturing of particles is effected by impacts of the particles on rotating fibres. The basis of the method consists of obtaining the largest possible number of impacts between particles and rotating fibres. The effectiveness of the method depends on the number of impacts, said number needing to be optimised. This patent refers to the problems posed by the fixing of the particles on the filaments and offers a solution, of giving the fibres, which are charged to collect via particles impact, bent inward complex cylindrical-conical shapes. The method used in this patent has certain drawbacks, particularly the explosion of water drips sprayed to wash the fibres. The sprayed liquid is only used to wash the fibres and not to fix the particles or dissolve gases. The method of the invention does not have the implementation problems of this patent.
The application WO 9741943 concerns a filter made of brushes or a conventional filter washed by a cleaning solution. The liquid may or may not be sprayed into the gas depending on the degree of dryness of the gas to be treated. It is the degree of dryness of the gas to be treated which determines if water is sprayed into the gas to be filtered. This spraying is accessory to and dependent on conditions.
The application WO97/44117 describes a gas purifying system which uses a rotary body with a complex structure for creating a large contact surface between a liquid film and the polluted gas. The spraying is only used to create the contact film between the polluted gas and a liquid which is then hydro-extracted. This method has the limitations of conventional filters, namely concerning the size of the particles to be captured. The large particles clog it which can be avoided by increasing the section of the tubes but the capturing effectiveness of the small particles is then reduced.
The devices of the prior art use water to wash conventional filters or increase air/gas contact by spreading a liquid film on complex or simple surfaces.
None of these devices use the fixing capacities of mist or the extremely large contact surface of the spherical droplets of mist.
These devices are not totally satisfactory for several reasons.
Firstly, this filtering method requires the use of increasingly successive finer filters so as to be able to stop the particles of different sizes, and these filters often need to be completed for example by electrostatic filters for stopping the finest particles.
Furthermore, the succession of filters constitutes an obstacle for the flow of the treated gas. During use, the more the filters have stopped particles, the more they obstruct the flow of the gas to be treated which clogs the filters and requires replacements be made or frequent cleanings so as to keep an acceptable yield in the filtering operation.
In addition, the materials separated from the filtered gas remain pulverulent and ill-suited for handling which often requires that the dust and waste collected be treated. These separated matter are bulky and quickly fill the device intended to receive them or even clog it if the device is a filter, this being the case for a household vacuum cleaner.
Moreover, current filters of this type are ill-adapted to filtering extremely small particles or low concentration particles or for filtering gases charged with fumes, particles or dust.
Finally, these filters are unable to eliminate undesirable or toxic gases mixed for example with the air to be purified.
OBJECT OF THE INVENTION
The object of the present invention is to provide a new solution for filtering gases including air and able to put right these drawbacks.
To this effect, the invention concerns for the most part a device conforming to claim 1.
SUMMARY OF THE INVENTION
The gas to be treated is sucked up by suction means, such as a propeller which rotates in the opposite direction of the adsorbing mass. An adsorbent mist is added to the incoming flow to be treated by a mist generator. The gas is mixed with the adsorbent mist and passes through a ‘gases path’. The adsorbent mist/gas mixture traverses a rotating adsorbent structure and then the treated gas is removed via the outlet. The reformed liquid and what it has fixed is removed and eventually treated and recycled.
The invention uses the adsorption phenomenon which consists of accumulating a surface at the interface between two phases (gas/liquid or liquid/liquid for example). This derives from intermolecular attraction forces of varied type and intensity for rendering the condensed liquid or solid phases coherent. A molecule irregularly attracted by the other molecules of two phases shall find a position forcibly favourable to the surface of the phase which attracts it most: this shall be called the adsorbent. The adsorbed molecules constitute the adsorbate. If the energy or kinetic conditions enable the molecule to penetrate the adsorbent phase, there is adsorption. Adsorption is a penetration phenomenon with fixing of molecules in an absorbing medium.
Each of the stages of the treatment may be effected in various ways.
The adsorbent mist is most often obtained from water. It can also be obtained from fatty liquid matter, solvents or various chemical solutions. The diameters of the droplets may vary depending on the applications.
The type of sprayed liquid may vary depending on requirements. A spraying of larger droplets can be added to the mist, said droplets carrying out a first fixing of the droplets of the mist by means of coalescence. The mist generator can be a spray nozzle, an ultrasonic system, etc.
It is possible to add to the liquid to make the mist various chemical products, especially detergents, “amphiphylic” substances (hydrophiles and lipophiles).
Electric, electrostatic, heat, luminous and pressure devices can be added to this stage of the process.
A linear path for the gases is the simplest and can suffice.
It is possible to add to the system various elements which optimise its functioning. For example, it is possible to add one or several helical wipers which, when placed in rotation, scrape the wall of the path of the gases and bring towards the rotary adsorbent structure the materials or liquids having been able to be deposited on the wall of the path of the gases.
It is possible to increase the distance traversed by the mist/gas mixture, add various means to favour the gas/mist contacts (wings, baffles) and provoke turbulences also favouring the gas/mist contact to be treated.
It is possible to increase the pressure in the gases path and at the level of the rotary adsorbent structure by a system of increasing pitch rotary wings (then decreasing after the passage through the rotary adsorbent structure).
During the passage of the gases path, it is possible to re-inject the mist of droplets, said mist being different from the first mist.
The rotary adsorbent structure can be embodied according to a large number of methods conforming to the applications of the method.
The simplest structure consists of a thin or thick disk of natural or synthetic microfibres organised into a sufficiently loose network so as to avoid excessively braking the gases to be treated and sufficiently dense or thick to totally adsorb the mist and what it has captured and to which it is fixed.
Other adsorbent structures
Drucker William A.
Silverman Stanley S.
Vanoy Timothy C
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