GB2319191A - A particulate matter concentrator - Google Patents
A particulate matter concentrator Download PDFInfo
- Publication number
- GB2319191A GB2319191A GB9623868A GB9623868A GB2319191A GB 2319191 A GB2319191 A GB 2319191A GB 9623868 A GB9623868 A GB 9623868A GB 9623868 A GB9623868 A GB 9623868A GB 2319191 A GB2319191 A GB 2319191A
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- GB
- United Kingdom
- Prior art keywords
- particulate matter
- temperature
- deposition
- deposition surface
- evaporation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D49/00—Separating dispersed particles from gases, air or vapours by other methods
- B01D49/02—Separating dispersed particles from gases, air or vapours by other methods by thermal repulsion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D43/00—Separating particles from liquids, or liquids from solids, otherwise than by sedimentation or filtration
Abstract
A particulate matter concentrator 1 for separating particles from a fluid comprises a surface 8 on which the particles are deposited, and an element 13 for heating the surface after deposition has taken place in order to evaporate the deposited particles. There may be an additional surface 7 spaced from the first surface 8, forming a path 6 for fluid flow between the surfaces. Surface 7 has a heating element 11 that may heat the surface to a temperature greater than that of surface 8, causing particles in the fluid to move by thermophoresis toward the cooler surface and be deposited thereon. Other separation methods such as using electromotive forces, magnetic forces, photophoresis, diffusion, electromagnetic forces or inertial forces may be employed instead of or in addition to thermophoresis to cause deposition on surface 8. The fluid is preferably air, but gases and liquids may also be used as the fluid medium. A pump means 5 may create a constant fluid flow rate through path 6. Each heat element preferably has a temperature control unit, and the surface 8 may have a cooling element. The heat element may be a halogen lamp and the surfaces 7, 8 may be of glass, aluminium or copper. The period of time for which the surface is at the evaporation temperature or greater is less than the deposition time.
Description
"A particulate matter concentrator"
THIS INVENTION relates to a particulate matter concentrator and more particularly to a particulate matter concentrator incorporating means for depositing particulate matter on a first surface and means for evaporating said particulate matter.
Conventional particulate matter concentrators operate on the principle of virtual impaction. This allows highly dispersed airborne particulate matter to be concentrated by making use of the difference in momentum between the airborne particulate matter and a carrier gas.
The principle of virtual impaction is well known in the aerosol technical field.
The present invention provides an entirely different method of concentrating particulate matter suspended or dispersed in a fluid such as air.
The disadvantage of the virtual impaction concentration method is that the system requires the use of two separate flows whereas systems embodying the present invention only need utilise a single flow.
Concentrators embodying the present invention also benefit from a greater concentration ratio of particulate matter than that provided by virtual impaction methods, a decrease in the size and weight of the concentrator, an increase in the range of sizes of particulate matter which can be concentrated. Additionally, a method embodying the present invention allows selective measurement of the concentration of different substances present in the concentrated particulate matter.
One aspect of the present invention provides a particulate matter concentrator comprising means to deposit particulate matter suspended in a fluid on a deposition surface and a heat element operable to heat the deposition surface to increase the temperature of the deposition surface to evaporate particulate matter deposited thereon.
A further aspect of the present invention provides a particulate matter concentrator comprising a first heat element operable to heat a deposition surface and a second heat element operable to heat a second surface, the deposition surface and second surface being spaced apart from one another to define therebetween a fluid flow passage, the first heat element being operable to heat the deposition surface to a first temperature and the second heat element being operable to heat the second surface to a second temperature greater than the first temperature such that a temperature gradient is established between the deposition surface and the second surface to cause a thermophoretic force to deposit particulate matter suspended in a fluid in the fluid flow passage onto the deposition surface, the first heat element also being operable to increase the temperature of the deposition surface to evaporate particulate matter deposited thereon.
Another aspect of the present invention provides a method of concentrating particulate matter suspended in a fluid comprising the steps of depositing the particulate matter onto a deposition surface for a predetermined deposition time; and increasing the temperature of the deposition surface to an evaporation temperature at which evaporation of particulate matter deposited on the deposition surface occurs, wherein the period of time for which the deposition surface is at the evaporation temperature or greater is less than the deposition time.
A further aspect of the present invention provides a method of concentrating particulate matter suspended in a fluid comprising the steps of: heating a deposition surface to a first temperature; heating a second surface to a second temperature, said second temperature being greater than the first temperature to establish a temperature gradient between the deposition surface and the second surface such that a thermophoretic force is created which deposits particulate matter suspended in the fluid between the deposition surface and the second surface onto the deposition surface; maintaining said first and second temperatures for a predetermined deposition time; and increasing the temperature of the deposition surface to an evaporation temperature at which evaporation of particulate matter deposited on the deposition surface occurs, wherein the period of time for which the deposition surface is at the evaporation temperature or greater is less than the deposition time.
In order that the present invention may be more readily understood, embodiments thereof will now be described with reference to the accompanying drawing which shows a schematic representation of a particulate matter concentrator embodying the present invention.
Referring to the Figure, a particulate matter concentrator 1 embodying the present invention comprises a collection and evaporation unit 2, an inlet conduit 3, an outlet conduit 4 and a pump 5 connected to the outlet conduit 4.
The inlet conduit 3 is open at one end and is in fluid communication with, for example, a volume of air or other fluid in which a number of particles are dispersed or suspended. The other end of the conduit 3 is in fluid communication with a chamber 6 within the collection and evaporation unit 2. The chamber 6 comprises a fluid flow passage and is defined by an upper surface 7, a lower deposition surface 8 and two side walls. The upper surface 7 is spaced apart from the lower surface 8 by a predetermined distance which is, for example, approximately 0.3mm. Preferably, the surfaces 7,8 are glass, aluminium or copper surfaces. These surfaces may be polished so that the surfaces may be scanned using a scanning electron microscope.
A heating element 11 is located behind the upper surface 7 and is thermally coupled to the heating surface 7 such that when heat is radiated from the heating element 11, the heat is conducted to the upper surface 7 and radiated therefrom. The temperature of the heating element 11 is controlled by a temperature control unit 12 which is located remote from the collection and evaporation unit 2.
A similar heating element 13 is located behind the lower surface 8. Again, the heating element 13 is thermally coupled to the lower surface 8 such that heat generated by the heating element 13 is radiated from the lower surface 8. The temperature of the heating element 13 is controlled by another temperature control unit 14 located remote from the collection and evaporation unit 2.
The heating elements 11,13 are in the form of resistive elements which are heated by providing a very high through current. Alternatively, a halogen lamp or another light (e.g. infrared source) may be used as the heating element, the radiant heat being directed onto a black foil layer (not shown) laminated to the rear side of one of the surfaces 7,8. This form of construction enables evaporation temperatures to be reached very quickly, i.e.
in the order of 0.5 seconds or less. It is, therefore, preferable that the heating elements 11, 13 have a very low inertia, i.e. they are able to achieve large changes in temperature quickly. The aforementioned two examples of such low inertia heating elements are not restrictive and the use of other low inertia heating elements is envisaged.
The inlet conduit 3 provides the entrance to the chamber 6 and the outlet conduit 4 which is connected to the chamber 6 provides the exit from the chamber 6. The pump 5 draws, for example, air from the volume of air located in fluid communication with the inlet conduit 3 through the inlet conduit 3, into the chamber 6 and out of the chamber 6 through the outlet conduit 4. The pump 5 is controllable to provide a steady flow rate Q of fluid through the chamber 6. Preferably, the pump 5 is also reversible so as to provide a flow from the outlet conduit 4, through the chamber 6 and out of the inlet conduit 3.
It is possible to connect an optical particulate matter counter or an instrument to measure particulate matter concentration based on visible/infrared techniques to one of the conduits 3,4.
In operation, the concentrator works in two distinct stages: a collection. process and an evaporation process. In the first collection process, the temperature control units 12,14 set the temperatures of the heating elements 11,13 to produce temperatures T1 and T2, respectively, at upper surface 7 and lower surface 8. In one example, T1 is 200"C. and T2 is 20 C. Temperature T1 is greater than temperature T2 such that a temperature gradient exists between the upper surface 7 and the lower surface 8.
The temperature control units maintain this temperature gradient. The presence of the temperature gradient causes a thermophoretic force which acts upon particulate matter suspended in the fluid medium flowing through the chamber 6.
Thermophoresis is a phenomenon by which aerosol particulate matter, in the steady state, under the influence of a- temperature gradient in the gas and of friction, move with constant velocity towards the lower temperature.
The thermophoretic force displaces particulate matter in the direction of the colder lower surface 8 of the collection and evaporation unit 2. Once the particulate matter is in contact with the lower surface 8 or is in contact with other particulate matter located on the surface 8, it becomes effectively stuck to the surface 8 or the other particulate matter and is not displaced by the flow of the fluid medium through the chamber 6. Even if the temperature gradient is removed such that both surfaces 7,8 are at the same temperature, the particulate matter on the surface 8 remains unmoved. Thus, a certain mass of particulate matter is deposited onto the lower surface 8. The mass Mi of particulate matter of a certain substance i deposited onto the lower surface 8 is defined by the formula, Mi = CiQtdep, where Ci is the concentration of particulate matter in the medium flowing through the chamber 6, Q is the flow rate of the medium through the chamber 6 and tdep, the deposition time, is the period of time over which the medium flows through the chamber 6.
The deposition time tdep is in the order of 10 seconds to a number of hours. Over this period of time, a large volume of fluid medium passes through the chamber 6, in the order of 102 cm3, litres or several cubic metres, and substantially all the particulate matter suspended in the fluid medium are deposited on the lower surface 8.
It is envisaged that a cooling element (not shown) may be provided, being thermally coupled to the lower surface 8 in order to cool the lower surface 8. This could enable deposition of volatile compounds which may otherwise react at higher temperatures, and would also increase the temperature gradient between the upper surface 7 and the lower surface 8.
The second stage comprises the evaporation process.
In this process, the temperature of the heating element 13 is increased rapidly from the low temperature T2 to a temperature approaching T1 or greater. The particulate matter deposited on the lower surface 8 is evaporated as the temperature of the lower surface 8 increases.
Preferably, the heating element 13 increases the temperature at the lower surface 8 to a pre-defined evaporation temperature, TeV, at which only particulate matter of a certain substance evaporates. The time for which the lower surface 8 is at the evaporation temperature Tev or greater is evaporation time. The evaporation temperature Tev is achieved substantially instantaneously, i.e. within 0.01 to 10 seconds. A typical evaporation time is, for example, 0.5 seconds.
As will be appreciated, although the deposition of the particulate matter onto the lower surface 8 takes place over a long period of time, varying from, for example, 10 seconds to a number of hours, all the particulate matter of a particular substance is evaporated from the lower surface almost instantly once the lower surface 8 reaches the evaporation temperature for that particular substance.
The flow passing through chamber 6, immediately after evaporation of the particular matter has taken place, now contains the entire amount of the matter in a gas form.
When the flow of these evaporated substances comes out of chamber 6, the temperature of the flow is decreased due to heat transfer to the walls of the outlet 4. The evaporated substances condense and form new particulate matter.
Particulate matter was deposited from the large volume of fluid medium over the deposition time. The concentration of particulate matter is now, therefore, much greater.
A commercially available optical particulate matter counter or other instrument to measure particulate matter can be used to measure the concentration of the particulate matter released by the evaporation/condensation process.
Since the volume of air at the outlet of the chamber 6 contains a much greater concentration of the particulate matter than would be the case if the particulate matter was being measured simply by passing through a conduit into the optical particulate matter counter or another instrument, the measurement of the concentration can be made with a greater degree of accuracy since the instrument is not attempting to measure a very low concentration of particulate matter per unit volume but, instead, a very high concentration of particulate matter per unit volume.
Thus, not only is it possible to produce a more accurate measurement of the concentration, it is also possible to use a less sensitive and hence cheaper instrument for the measurement process.
The concentration of particulate matter released by the evaporation/condensation process, Cevi is Mev/(Qtev) where Mev is the mass of particulate matter evaporated, tev is the period of evaporation and Q is the flow rate out of the outlet conduit 4 from the chamber 6. MeV is substantially equal to Mi (the mass of particulate matter of a certain substance i deposited during the deposition period, tdep) for each particular substance.
The ratio R of the concentration of particulate matter achieved using the invention, Cev, to the normal concentration, Ci, of particulate matter suspended in a fluid medium gives an indication of the effectiveness of the invention. Since C0v = Mev/(Qtev) and Mev z Mi, Ccv = Citdep/teV and thus R = tdep/tev. Accordingly, the effectiveness of the concentrator is improved by long deposition times, step, and short evaporation times, tev All substances which are deposited on the lower surface 8 have their own characteristic evaporation temperature. It is therefore possible to evaporate substances selectively and obtain information about the chemical composition of particulate matter being evaporated. For example, sodium chloride particulate matter has an evaporation temperature of 6000C., whereas ammonia sulphate has an evaporation temperature of 300/4000C.
This form of particulate matter concentration works on most forms of particulate matter, be they solid or liquid. The concentration process works not only for metal halogenides, metal particulate matter, ceramic particulate matter but also for organic materials.
The concentrator embodying the present invention can be used in a wide range of fields such as environmental control to measure air pollution and in emission control systems for automobiles and the like. Similarly, in a clean room environment one can make use of the selective evaporation process allowed by embodiments of the claimed invention in order to identify what actions or materials are causing contamination in the clean room by measuring the concentration and identifying the chemical composition of the evaporated particulate matter.
Although the above-mentioned embodiment describes the medium in which the particulate matter is suspended or dispersed as being air, it is also possible to use other gases or, indeed, liquids as the fluid medium.
Other embodiments of the invention are based on using inertial forces, electromagnetic forces, electromotive forces, magnetic forces, photophoresis (a thermophoresis effect in which the temperature gradient between surfaces is obtained by irradiation with light) or diffusion, or a combination thereof, to deposit particulate matter on either a solid substrate or into a temperature resistant aerosol filter (glass, quartz, etc.). In the case of inertial deposition, one needs only one heating element to evaporate working material. It is possible to use multi-stage cascade impactors to deposit particulate matter. In this case, each stage should have a heating device. Alternatively, substrates with deposited particulate matter can be removed from the impactor and passed into an evaporation unit that is similar to the collection and evaporation unit 2 but contains only one lower heating element.
In the case of deposition into a filter material (such as an aerosol filter, silica gel, or the like) particulate matter is deposited inside and on the filtering medium. The heating element or heating device is provided which is able to heat the filter material. After passing through the filter material, the vapours of the particulate matter are condensed and form particulate matter with a high concentration.
Claims (32)
1. A particulate matter concentrator comprising means to deposit particulate matter suspended in a fluid on a deposition surface and a heat element operable to heat the deposition surface to increase the temperature of the deposition surface to evaporate particulate matter deposited thereon.
2. A particulate matter concentrator according to
Claim 1, wherein the heat element comprises a first heat element operable to heat the deposition surface and a second heat element operable to heat a second surface, the deposition surface and the second surface being spaced apart from one another to define therebetween a fluid flow passage, the first heat element being operable to heat the deposition surface to a first temperature and the second heat element being operable to heat the second surface to a second temperature greater than the first temperature such that a temperature gradient is established between the deposition surface and the second surface to cause a thermophoretic force to deposit particulate matter suspended in a fluid in the fluid flow passage onto the deposition surface, the first heat element also being operable to increase the temperature of the deposition surface to evaporate particulate matter deposited thereon.
3. A particulate matter concentrator according to
Claim 2, wherein a pump means is provided at one end of the fluid flow passage to create a constant fluid flow rate through the fluid flow passage.
4. A particulate matter concentrator according to
Claim 2 or 3, wherein each heat element has an associated temperature control unit which is preset to maintain a respective surface at a predetermined temperature for a predetermined period of time, the temperature control unit for the first heat element also being operable to increase the temperature of the deposition surface from said first temperature to a higher temperature and maintain said higher temperature for a predetermined time.
5. A particulate matter concentrator according to any one of Claims 2 to 4, wherein the deposition surface has a cooling element to enable deposition of volatile compounds and to increase the temperature gradient between the deposition surface and the second surface.
6. A particulate matter concentrator according to
Claim 4 or 5, wherein the higher temperature comprises an evaporation temperature of a particulate substance deposited on the deposition surface, each particulate substance having a characteristic evaporation temperature.
7. A particulate matter concentrator according to
Claim 6, wherein the temperature control unit for the first heat element is operable to increase the temperature of the deposition surface to higher characteristic evaporation temperatures of further particulate substances and to maintain said high evaporation temperatures for predetermined times.
8. A particulate matter concentrator according to any preceding claim, wherein the or each heat element comprises a low inertia heat element.
9. A particulate matter concentrator according to any preceding claim, wherein the or each heat element comprises an electric resistive element.
10. A particulate matter concentrator according to any one of Claims 1 to 8, wherein the or each heat element comprises a halogen lamp heat source.
11. A particulate matter concentrator according to any preceding claim, wherein the or each surface is backed with a layer of black foil.
12. A particulate matter concentrator according to any preceding claim, wherein the first heat element is operable to increase the temperature at a predetermined rate to evaporate a number of different substances sequentially.
13. A particulate matter concentrator according to any preceding claim, wherein a particulate matter concentration measurement means is provided at one end of the concentrator to measure the concentration of particulate matter evaporated from the deposition surface.
14. A particulate matter concentrator according to any preceding claim, wherein the fluid comprises a gas or a mixture of gases.
15. A particulate matter concentrator according to
Claim 14, wherein the gas is air.
16. A particulate matter concentrator according to any preceding claim, wherein the deposition surface and/or the second surface comprises a glass, aluminium or copper surface.
17. A particulate matter concentrator according to any preceding claim, wherein the deposition surface and/or the second surface is a polished surface.
18. A method of concentrating particulate matter suspended in a fluid comprising the steps of: depositing the particulate matter onto a deposition surface for a predetermined deposition time; and increasing the temperature of the deposition surface to an evaporation temperature at which evaporation of particulate matter deposited on the deposition surface occurs, wherein the period of time for which the deposition surface is at the evaporation temperature or greater is less than the deposition time.
19. A method according to Claim 18, wherein the particulate substances deposited on the deposition surface each have a characteristic evaporation temperature.
20. A method according to Claim 19, wherein the step of increasing the temperature of the deposition surface comprises the step of increasing the temperature to the characteristic evaporation temperature of a selected particulate substance.
21. A method according to any one of Claims 18 to 20, wherein evaporated particulate matter is collected for subsequent measurement.
22. A method according to any one of Claims 18 to 21, wherein the evaporation time comprises the time for which the deposition surface is at an evaporation temperature or greater, the evaporation time being at least an order of magnitude less than the deposition time and the time taken for the deposition surface to reach the evaporation temperature from the first temperature is substantially instantaneous.
23. A method according to Claim 22, wherein the evaporation time is in the order of seconds or less.
24. A method according to Claim 22, wherein the evaporation time is in the order of 0.5 seconds.
25. A method according to any one of Claims 18 to 24, wherein the deposition time is in the order of tens of seconds or more.
26. A method according to Claim 25, wherein the deposition time is in the order of minutes.
27. A method according to Claim 25, wherein the deposition time is in the order of hours.
28. A method according to any one of Claims 18 to 27, wherein the method comprises the further steps of heating the deposition surface to a first temperature; heating a second surface to a second temperature, said second temperature being greater than the first temperature to establish a temperature gradient between the deposition surface and the second surface such that a thermophoretic force is created which deposits particulate matter suspended in the fluid between the deposition surface and the second surface onto the deposition surface; and maintaining said first and second temperatures for the predetermined deposition time.
29. A method according to any one of Claims 18 to 27, wherein particulate matter is deposited on the deposition surface by one or a combination of thermophoresis, photophoresis, electromagnetic force, electromotive force, magnetic force, inertial force or diffusion.
30. A particulate matter concentrator substantially as hereinbefore described with reference to and as shown in the accompanying figure.
31. A method of concentrating particulate matter substantially as hereinbefore described with reference to the figure.
32. Any novel feature or combination of features disclosed herein.
32. Any novel feature or combination of features disclosed herein.
Amendments to the claims have been filed as tollows 1. A particulate matter concentrator comprising means to deposit particulate matter suspended in a fluid on a deposition surface and a heat element operable to heat the deposition surface to increase the temperature of the deposition surface to evaporate particulate matter deposited thereon, wherein means are provided to condense evaporated substances and form new particulate matter.
2. A particulate matter concentrator according to
Claim 1, wherein the heat element comprises a first heat element operable to heat the deposition surface and a second heat element operable to heat a second surface, the deposition surface and the second surface being spaced apart from one another to define therebetween a fluid flow passage, the first heat element being operable to heat the deposition surface to a first temperature and the second heat element being operable to heat the second surface to a second temperature greater than the first temperature such that a temperature gradient is established between the deposition surface and the second surface to cause a thermophoretic force to deposit particulate matter suspended in a fluid in the fluid flow passage onto the deposition surface, the first heat element also being operable to increase the temperature of the deposition surface to evaporate particulate matter deposited thereon.
3. A particulate matter concentrator according to
Claim 2, wherein a pump means is provided at one end of the fluid flow passage to create a constant fluid flow rate through the fluid flow passage.
4. A particulate matter concentrator according to
Claim 2 or 3, wherein each heat element has an associated temperature control unit which is preset to maintain a respective surface at a predetermined temperature for a predetermined period of time, the temperature control unit for the first heat element also being operable to increase the temperature of the deposition surface from said first temperature to a higher temperature and maintain said higher temperature for a predetermined time.
5. A particulate matter concentrator according to any one of Claims 2 to 4, wherein the deposition surface has a cooling element to enable deposition of volatile compounds and to increase the temperature gradient between the deposition surface and the second surface.
6. A particulate matter concentrator according to
Claim 4 or 5, wherein the higher temperature comprises an evaporation temperature of a particulate substance deposited on the deposition surface, each particulate substance having a characteristic evaporation temperature.
7. A particulate matter concentrator according to
Claim 6, wherein the temperature control unit for the first heat element is operable to increase the temperature of the deposition surface to higher characteristic evaporation temperatures of further particulate substances and to maintain said high evaporation temperatures for predetermined times.
8. A particulate matter concentrator according to any preceding claim, wherein the or each heat element comprises a low inertia heat element.
9. A particulate matter concentrator according to any preceding claim, wherein the or each heat element comprises an electric resistive element.
10. A particulate matter concentrator according to any one of Claims 1 to 8, wherein the or each heat element comprises a halogen lamp heat source.
11. A particulate matter concentrator according to any preceding claim, wherein the or each surface is backed with a layer of black foil.
12. A particulate matter concentrator according to any preceding claim, wherein the first heat element is operable to increase the temperature at a predetermined rate to evaporate a number of different substances sequentially.
13. A particulate matter concentrator according to any preceding claim, wherein a particulate matter concentration measurement means is provided at one end of the concentrator to measure the concentration of particulate matter evaporated from the deposition surface.
14. A particulate matter concentrator according to any preceding claim, wherein the fluid comprises a gas or a mixture of gases.
15. A particulate matter concentrator according to
Claim 14, wherein the gas is air.
16. A particulate matter concentrator according to any preceding claim, wherein the deposition surface and/or the second surface comprises a glass, aluminium or copper surface.
17. A particulate matter concentrator according to any preceding claim, wherein the deposition surface and/or the second surface is a polished surface.
18. A method of concentrating particulate matter suspended in a fluid comprising the steps of: depositing the particulate matter onto a deposition surface for a predetermined deposition time; increasing the temperature of the deposition surface to an evaporation temperature at which evaporation of particulate matter deposited on the deposition surface occurs, wherein the period of time for which the deposition surface is at the evaporation temperature or greater is less than the deposition time; and condensing the evaporated substances to form new particulate matter.
19. A method according to Claim 18, wherein the particulate substances deposited on the deposition surface each have a characteristic evaporation temperature.
20. A method according to Claim 19, wherein the step of increasing the temperature of the deposition surface comprises the step of increasing the temperature to the characteristic evaporation temperature of a selected particulate substance.
21. A method according to any one of Claims 18 to 20, wherein evaporated particulate matter is collected for subsequent measurement.
22. A method according to any one of Claims 18 to 21, wherein the evaporation time comprises the time for which the deposition surface is at an evaporation temperature or greater, the evaporation time being at least an order of magnitude less than the deposition time and the time taken for the deposition surface to reach the evaporation temperature from the first temperature is substantially instantaneous.
23. A method according to Claim 22, wherein the evaporation time is in the order of seconds or less.
24. A method according to Claim 22, wherein the evaporation time is in the order of 0.5 seconds.
25. A method according to any one of Claims 18 to 24, wherein the deposition time is in the order of tens of seconds or more.
26. A method according to Claim 25, wherein the deposition time is in the order of minutes.
27. A method according to Claim 25, wherein the deposition time is in the order of hours.
28. A method according to any one of Claims 18 to 27, wherein the method comprises the further steps of heating the deposition surface to a first temperature; heating a second surface to a second temperature, said second temperature being greater than the first temperature to establish a temperature gradient between the deposition surface and the second surface such that a thermophoretic force is created which deposits particulate matter suspended in the fluid between the deposition surface and the second surface onto the deposition surface; and maintaining said first and second temperatures for the predetermined deposition time.
29. A method according to any one of Claims 18 to 27, wherein particulate matter is deposited on the deposition surface by one or a combination of thermophoresis, photophoresis, electromagnetic force, electromotive force, magnetic force, inertial force or diffusion.
30. A particulate matter concentrator substantially as hereinbefore described with reference to and as shown in the accompanying figure.
31. A method of concentrating particulate matter substantially as hereinbefore described with reference to the figure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9623868A GB2319191B (en) | 1996-11-15 | 1996-11-15 | A particulate matter concentrator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9623868A GB2319191B (en) | 1996-11-15 | 1996-11-15 | A particulate matter concentrator |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9623868D0 GB9623868D0 (en) | 1997-01-08 |
| GB2319191A true GB2319191A (en) | 1998-05-20 |
| GB2319191B GB2319191B (en) | 2000-09-27 |
Family
ID=10803054
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9623868A Expired - Fee Related GB2319191B (en) | 1996-11-15 | 1996-11-15 | A particulate matter concentrator |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2319191B (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2350804A (en) * | 1999-06-12 | 2000-12-13 | Johnson Matthey Plc | Removing particulate matter from gas by thermophoresis and combustion |
| WO2001017662A2 (en) * | 1999-09-03 | 2001-03-15 | The Cleveland Clinic Foundation | Continuous particle and molecule separation with an annular flow channel |
| WO2001032294A1 (en) * | 1999-11-05 | 2001-05-10 | Imperial College Of Science, Technology And Medicine | Gas filtration |
| EP1072765A3 (en) * | 1999-07-26 | 2003-06-11 | Man Nutzfahrzeuge Ag | Method and apparatus for separating fine particulate matter from exhaust gas of internal combustion engine |
| WO2007003578A1 (en) * | 2005-07-01 | 2007-01-11 | Commissariat A L'energie Atomique | Method and device for selectively sorting particles using at least one thermophoretic force |
| WO2010108914A1 (en) * | 2009-03-25 | 2010-09-30 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | System for purifying a fluid laden with particles by thermophoretic force |
| US8012245B2 (en) | 2006-04-07 | 2011-09-06 | Technische Universiteit Eindhoven | Method and device for reducing formation of particulate matter in gas streams |
| CN102820070A (en) * | 2012-08-23 | 2012-12-12 | 华北电力大学 | Helium-filled system for removing grains in gas |
| CN102842346A (en) * | 2012-08-27 | 2012-12-26 | 华北电力大学 | System for processing serious accidents caused by helium pressurization in nuclear power plant |
| WO2016156035A1 (en) * | 2015-03-27 | 2016-10-06 | Koninklijke Philips N.V. | Protecting an optical particle sensor from particulate deposits by thermophoresis |
| CN106964230A (en) * | 2017-05-11 | 2017-07-21 | 南京工业大学 | A kind of thermophoresis air filter |
| WO2019099571A1 (en) * | 2017-11-14 | 2019-05-23 | Aerodyne Microsystems Inc., a Delaware Corporation | Airborne particle detection system with thermophoretic scanning |
| US10894943B2 (en) | 2015-10-27 | 2021-01-19 | Hewlett-Packard Development Company, L.P. | Volatile organic compound transport |
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| CN113082910B (en) * | 2021-04-14 | 2023-04-07 | 浙江大学医学院附属邵逸夫医院 | Method and device for catching and killing ultrafine biological particles in air |
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| EP0277615A2 (en) * | 1987-02-02 | 1988-08-10 | Nihon Shinku Gijutsu Kabushiki Kaisha | Fine particle collector arrangement for vacuum pumps |
| US4816046A (en) * | 1987-04-22 | 1989-03-28 | Nihon Shinku Gijutsu Kabushiki Kaisha | Fine particle collector trap for vacuum evacuating system |
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Also Published As
| Publication number | Publication date |
|---|---|
| GB9623868D0 (en) | 1997-01-08 |
| GB2319191B (en) | 2000-09-27 |
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