US1325124A - Process and apparatus for precipitating matter from gases - Google Patents
Process and apparatus for precipitating matter from gases Download PDFInfo
- Publication number
- US1325124A US1325124A US1325124DA US1325124A US 1325124 A US1325124 A US 1325124A US 1325124D A US1325124D A US 1325124DA US 1325124 A US1325124 A US 1325124A
- Authority
- US
- United States
- Prior art keywords
- gas
- gases
- matter
- precipitating
- active electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000007789 gas Substances 0.000 title description 86
- 230000001376 precipitating Effects 0.000 title description 24
- 238000000034 method Methods 0.000 title description 16
- 230000002745 absorbent Effects 0.000 description 30
- 239000002250 absorbent Substances 0.000 description 30
- 239000003517 fume Substances 0.000 description 14
- 239000003610 charcoal Substances 0.000 description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 12
- 239000000463 material Substances 0.000 description 10
- 238000010521 absorption reaction Methods 0.000 description 8
- 230000001965 increased Effects 0.000 description 8
- 230000001939 inductive effect Effects 0.000 description 8
- 230000001473 noxious Effects 0.000 description 8
- 238000001556 precipitation Methods 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 239000002245 particle Substances 0.000 description 4
- 230000029058 respiratory gaseous exchange Effects 0.000 description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-N Carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 241000255925 Diptera Species 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 2
- 241001272996 Polyphylla fullo Species 0.000 description 2
- 235000015450 Tilia cordata Nutrition 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 241001349296 Tragia volubilis Species 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 2
- 230000003190 augmentative Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006011 modification reaction Methods 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 2
- 229920000136 polysorbate Polymers 0.000 description 2
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
- B03C3/02—Plant or installations having external electricity supply
- B03C3/04—Plant or installations having external electricity supply dry type
- B03C3/14—Plant or installations having external electricity supply dry type characterised by the additional use of mechanical effects, e.g. gravity
- B03C3/155—Filtration
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S55/00—Gas separation
- Y10S55/38—Tubular collector electrode
Definitions
- a further object of my invention is to provide an electrical device for the removal of suspended particles of matter by ionizing or electrifyin said particles.
- Figure 1 is a diagrammatic view of an induction coil connected up with one form of the ionizing device, the latter being shown in section;
- Fig. 2 is a detailed view of .a modified means of supporting the active electrodes
- Fig. 3 is a sectional view of a portlon of a modified form of the device
- Fig. 4 is a sectional view of a portion of another modified form.
- Fig. 5 is a transverse sectional view showing another modified form.
- the active electrode is immediately surrounded by an insulator in the very part of the electric field where the greatest ionizing effect should take place, as for instance, in the patents to Hardie, 7 68,450, and Blake, 913,9411.
- these devices are primarily designed for stationary plants, while in the present invention one of the objects is to provide an ionizing apparatus which is portable, and which may be carried by a soldier, a fireman or any one else. who is liable to suffer in ury from breathing nox- 1ous fumes.
- a portable apparatus necessarily requires a light weight device for gen eratlng a relatively low voltage which volt age, however, must be sufiicient to cause an electricdischaiflge which will insure the precipitatlon of the noxious matter.
- I may make use of a small wire 6, which is disposed in the center of a tube 7 which serves as a dielectric, being made of lass or other suitable material.
- the tube is provided with end closures 8 and 9 respectively, and the wire 6 isnormally under the tension of a sprin to keep the wire straight.
- On the outsi e of the tube 7 is wound a wire 11,0ne terminal of the secondary 3 of the'induction c011 being connected to the wire 6, and the other to the wire 11.
- the tube 7 has an inlet 12, and an outlet 13, the arrows indi-- eating the direction of through the tube.
- the. electric discharge :ionizes the the gas in its passage from the inlet 12 to't e outlet 13, and causes the precipitation of the matter on the wire 6 as well as on the Walls of the tube 7.
- the outlet 13 is. connected to the mask (not shown) and the noxious'fumes are precipitated before entering the same.
- Fig. 3 l Associated with the gas masks which are flow Y of the gas in ordinary, use today, are devices for absorbing certain fumes and noxious matter, such absorbents as charcoal, and the like being largely employed. Now the ionization, which is accomplished by my device, tends to considerably increase the absorptive power of these agents.
- Fig. 3 l have shown a portion of a modified form of the device in which absorbent material, such as charcoal, is made use of, this absorbent material being shown at 14. Where an electric discharge takes place in a tube, such as that shown in Fig. 3, the electric wind produced greatly increases the absorption of gases.
- Fig. 2 l have shown a modified form of the device in which the active electrode 6 is coiled around a support 15, in this case a glass'tube. I find that this provides a means of keeping a small wire in position very easily.
- Fig. 4. I have shown a further modified form in which the active electrode 6 is supported by a tube 15, while the passive electrode 16 is on the exterior of an insulating tube or dielectric 17.
- Fig. 5 I have shown a further modified form in which the active electrode 9 is surrounded by passive electrodes 19, each insulated by tubes 20.
- Absorbent material such as charcoal 21, may be placed between the active electrode 9 and the tubes 20, containing the passive-electrodes 19.
- the active electrode has a relatively great curvature.
- the distinction berename tween the active and passive electrodes lies 111 the fact that the active electrode surface has this great curvature, while the curvature of the passive electrodes is made as small as convenient, and furthermore that the ionization takes place at the surface of the active electrode. Where the curvature of the surface is greater, less potential is required to break down the gas, or to cause a discharge.
- the electric wind causes an increase in the pressure of the gas in which it takes place.
- this electric wind pressure is often called the corona pressure.
- the magnitude of these results is proportional to the corona pressure, and that this pressure can be taken'as a measure of the action of the electrical discharge.
- a gaseous ionizing device comprising an active electrode in contact with the gas, an absorbent element in the field of the active electrode and in contact with the gas, and a passive electrode out of contact with the gas.
- An apparatus for precipitating matter from gases comprising an active electrode in contact with the gas, and having a relatively great surface curvature, and a passive electrode out of contact with the gas, and having a comparatively small surface curvature.
- An apparatus for precipitating matter from gases comprising an active electrode in contact with the gas and having a relatively great surface curvature, a passive electrode out of contact with the gas and having a comparatively small surface curvature, and a supporting dielectric between said active and said passive electrodes.
- the herein described process of precipitating matter from gases which consists in passing a stream'of gas into immediate contact with an active electrode and an absorbent element, and in causing an electric discharge from said electrode through the path of the stream of gas and in the immediate presence of the absorbent element.
- An apparatus for precipitating matter comparative'l from gases comprising an active electrode in contact with the gas, having a relatively great surface curvature, a passive electrode out of contact with the gas and having'a small surface curvature, a supporting ielectric between said active and said passive electrodes, and means for charging said electrodes from a source of electricity of relativelylow potential whereby matter in the gas is precipitated.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Electrostatic Separation (AREA)
Description
W. W. STRONG.
PROCESS AND APPARATUS FOR PRECIPITATING MATTER FROM GASES.
APPLICATION FlL-ED OCT. 23. 1918.
Patented Dec. 16,1919.
INVENTOR William Z. 6Zro7g.
26 A TTORNEYS UNITED sTATEs PATENT oEEIoE.
WILLIAM WALKER STRONG, OF MECHANICSBU'RG, PENNSYLVANIA.
PROCESS AND APPARATUS FOR PRECIFITATING MATTER FROM GASES.
To all whom it may concern:
Be it known that I, WILLIAM WALKER STRONG, a citizen of the United States, residing at Mechanicsburg, county of Cumberland, and State of Pennsylvania, have invented certain new and useful Improveinents in Processes and Apparatus for Precipitating Matter from Gases, of which the following is a specification.
A further object of my invention is to provide an electrical device for the removal of suspended particles of matter by ionizing or electrifyin said particles.
A further 0 ject of my invention 1s to provide an ionizing device to be used in connection with an absorbent, such as charcoal, or the like, for increasing the absorptive power of the latter.
A further object of my invention s to provide an ionizing device which requires a relatively small voltage to operate it, as compared with the amount of matter ionlzed.
Other objects and advantages will appear in the following specification, and the novel features of the device will be particularly pointed out in the appended claims.
My invention is illustrated 1n the accompanying drawings, forming part of this application, in which Figure 1 is a diagrammatic view of an induction coil connected up with one form of the ionizing device, the latter being shown in section;
Fig. 2 is a detailed view of .a modified means of supporting the active electrodes;
Fig. 3 is a sectional view of a portlon of a modified form of the device;
Fig. 4 is a sectional view of a portion of another modified form; and
Fig. 5 is a transverse sectional view showing another modified form.
The precipitation of suspended matter in gases by the use of electric discharges has, as far as I am aware,-been accomplished by Specification of Letters Patent.
Application filed October 23,,1918.
matter carried b Patented Dec. 16, 1919.
Serial No. 259,303.
the use of relatively great voltage. One reason for this is that in the devices hitherto proposed the active electrode is immediately surrounded by an insulator in the very part of the electric field where the greatest ionizing effect should take place, as for instance, in the patents to Hardie, 7 68,450, and Blake, 913,9411. Moreover, these devices are primarily designed for stationary plants, while in the present invention one of the objects is to provide an ionizing apparatus which is portable, and which may be carried by a soldier, a fireman or any one else. who is liable to suffer in ury from breathing nox- 1ous fumes. A portable apparatus necessarily requires a light weight device for gen eratlng a relatively low voltage which volt age, however, must be sufiicient to cause an electricdischaiflge which will insure the precipitatlon of the noxious matter.
In carrying out my invention I make use of a battery 1 which is connected with an induction coil having a primary wire 2, a secondary 3, a condenser 4, and an interrupter 5 for the primary circuit, this induction coil being of the ordinary buzzer type.
For the active electrode of the ionizer, I may make use of a small wire 6, which is disposed in the center of a tube 7 which serves as a dielectric, being made of lass or other suitable material. In the orm shown in Fig. 1, the tube is provided with end closures 8 and 9 respectively, and the wire 6 isnormally under the tension of a sprin to keep the wire straight. On the outsi e of the tube 7 is wound a wire 11,0ne terminal of the secondary 3 of the'induction c011 being connected to the wire 6, and the other to the wire 11. The tube 7 has an inlet 12, and an outlet 13, the arrows indi-- eating the direction of through the tube.
With an apparatus set up as shown in Fig. 1, the. electric discharge :ionizes the the gas in its passage from the inlet 12 to't e outlet 13, and causes the precipitation of the matter on the wire 6 as well as on the Walls of the tube 7. When such a device is used in connection with the gas mask, such as that in useby soldiers, the outlet 13 is. connected to the mask (not shown) and the noxious'fumes are precipitated before entering the same.
Associated with the gas masks which are flow Y of the gas in ordinary, use today, are devices for absorbing certain fumes and noxious matter, such absorbents as charcoal, and the like being largely employed. Now the ionization, which is accomplished by my device, tends to considerably increase the absorptive power of these agents. In Fig. 3 l have shown a portion of a modified form of the device in which absorbent material, such as charcoal, is made use of, this absorbent material being shown at 14. Where an electric discharge takes place in a tube, such as that shown in Fig. 3, the electric wind produced greatly increases the absorption of gases. Consider the case of a gas containing oxide of nitrogen that are to be absorbed: If these gases are passed over charcoal in the absence of an electrical discharge, the oxids of nitrogen will be absorbed as diffusion brings them into contact with the charcoal surface. Subject the gases to the action of the electric windand the rate of absorption will be greatly increased. It has been found by experiment that the rate of absorption can be increased e070.
in the case of gas masks for soldiers, it has been found that not all of thenoxious fumes are absorbed. With the use of the electric precipitating device certain. fumes which would be unaffected by the ordinary gas mask, will be precipitated. The use of an electrical precipitating device, further more, obviates the necessity of the use of a large quantity of absorbent by increasing the absorbing power. This is decided advantage, since any absorbent tends to increase the dificulty of breathing and there is a limit to the amount of absorbent that can be used.
In Fig. 2, l have shown a modified form of the device in which the active electrode 6 is coiled around a support 15, in this case a glass'tube. I find that this provides a means of keeping a small wire in position very easily.
In Fig. 4., I have shown a further modified form in which the active electrode 6 is supported by a tube 15, while the passive electrode 16 is on the exterior of an insulating tube or dielectric 17. The absorbent material 18, which in this instance may consist of moist soda lime for the absorption of oxids of nitrogen, is held in position by the use of a netting 19 such as cloth mosquito netting.
In Fig. 5, I have shown a further modified form in which the active electrode 9 is surrounded by passive electrodes 19, each insulated by tubes 20. Absorbent material, such as charcoal 21, may be placed between the active electrode 9 and the tubes 20, containing the passive-electrodes 19.
It will be observed that in each of the forms shown the active electrode has a relatively great curvature. The distinction berename tween the active and passive electrodes lies 111 the fact that the active electrode surface has this great curvature, while the curvature of the passive electrodes is made as small as convenient, and furthermore that the ionization takes place at the surface of the active electrode. Where the curvature of the surface is greater, less potential is required to break down the gas, or to cause a discharge.
If the electric discharge takes place in a closed vessel, it will be found that the electric wind causes an increase in the pressure of the gas in which it takes place. in the case where the electrodes .consist of a wire in a metallic pipe, this electric wind pressure is often called the corona pressure. In the production of chemical compounds, and the precipitation of fumes by means of the electrical discharge, it is found that the magnitude of these results is proportional to the corona pressure, and that this pressure can be taken'as a measure of the action of the electrical discharge.
I am aware that devices of the type described above have been used for ozonizing air. The present device, however, is not in" tended for such use, and on the other hand, the ozonizing of the air is a positive disadvantage as, for instance, in the case of the use of gas masks, where ozone would pro-- duce an irritating eflect. vAs far is I am aware, the precipitation of noxious fumes or other matter, from gases by an electric discharge in the immediate vicinity of an active, uninsulated electrode, has never been done, at comparatively low voltages.
Various modifications of the device might be made without departing in the least from the spirit and scope of the present invention.
I claim 1 1. A gaseous ionizing device, comprising an active electrode in contact with the gas, an absorbent element in the field of the active electrode and in contact with the gas, and a passive electrode out of contact with the gas.
2. An apparatus for precipitating matter from gases, comprising an active electrode in contact with the gas, and having a relatively great surface curvature, and a passive electrode out of contact with the gas, and having a comparatively small surface curvature.
3. An apparatus for precipitating matter from gases comprising an active electrode in contact with the gas and having a relatively great surface curvature, a passive electrode out of contact with the gas and having a comparatively small surface curvature, and a supporting dielectric between said active and said passive electrodes.
4. The herein described process of precipitating matter from gases which consists in bringing said gases into immediate contact with an active electrode, in the presence of an. absorbent element, and 1n causing an electric discharge from said electrode.
5. The herein described process of precipitating matter from gases. which consists in passing a stream'of gas into immediate contact with an active electrode and an absorbent element, and in causing an electric discharge from said electrode through the path of the stream of gas and in the immediate presence of the absorbent element.
6. The herein described steps in a process of precipitating matter from gases, which consists in passlng a stream of-gas into immediate contact with an absorbent, and in simultaneously ionizing the gas.
An apparatus for precipitating matter comparative'l from gases comprising an active electrode in contact with the gas, having a relatively great surface curvature, a passive electrode out of contact with the gas and having'a small surface curvature, a supporting ielectric between said active and said passive electrodes, and means for charging said electrodes from a source of electricity of relativelylow potential whereby matter in the gas is precipitated.
' 8. The herein described step in a process of precipitating matter from gases, which consists in augmenting the absorptive power of a gas absorbing material by placing the latter in the field of an electric discharge during the passage of gas past the absorbent;
WILLIAM WALKER STRONG.
Publications (1)
Publication Number | Publication Date |
---|---|
US1325124A true US1325124A (en) | 1919-12-16 |
Family
ID=3392571
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US1325124D Expired - Lifetime US1325124A (en) | Process and apparatus for precipitating matter from gases |
Country Status (1)
Country | Link |
---|---|
US (1) | US1325124A (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2708488A (en) * | 1953-02-16 | 1955-05-17 | Svenska Flaektfabriken Ab | Arrangement in emitting electrodes |
DE1040379B (en) * | 1953-03-07 | 1958-10-02 | Ludger Funder Dr Ing | Dust protection mask with electrostatically charged filter plates |
US2974747A (en) * | 1956-03-20 | 1961-03-14 | Borg Warner | Electric precipitators |
US3131104A (en) * | 1960-10-20 | 1964-04-28 | Tank Seal Products Company | Method and apparatus for applying protective coatings |
US3273317A (en) * | 1960-10-12 | 1966-09-20 | Vicard Pierre Georges | Sleeve filters |
US3750373A (en) * | 1971-10-01 | 1973-08-07 | R Olson | Electrostatic mist precipitator |
US4216000A (en) * | 1977-04-18 | 1980-08-05 | Air Pollution Systems, Inc. | Resistive anode for corona discharge devices |
US4737164A (en) * | 1984-07-06 | 1988-04-12 | Seinajoen Kylmakone A ja T Saikkonen Ky | Process for recovering contaminants from gases |
US4744910A (en) * | 1986-04-22 | 1988-05-17 | Voyager Technologies, Inc. | Electrostatic filter |
-
0
- US US1325124D patent/US1325124A/en not_active Expired - Lifetime
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2708488A (en) * | 1953-02-16 | 1955-05-17 | Svenska Flaektfabriken Ab | Arrangement in emitting electrodes |
DE1040379B (en) * | 1953-03-07 | 1958-10-02 | Ludger Funder Dr Ing | Dust protection mask with electrostatically charged filter plates |
US2974747A (en) * | 1956-03-20 | 1961-03-14 | Borg Warner | Electric precipitators |
US3273317A (en) * | 1960-10-12 | 1966-09-20 | Vicard Pierre Georges | Sleeve filters |
US3131104A (en) * | 1960-10-20 | 1964-04-28 | Tank Seal Products Company | Method and apparatus for applying protective coatings |
US3750373A (en) * | 1971-10-01 | 1973-08-07 | R Olson | Electrostatic mist precipitator |
US4216000A (en) * | 1977-04-18 | 1980-08-05 | Air Pollution Systems, Inc. | Resistive anode for corona discharge devices |
US4737164A (en) * | 1984-07-06 | 1988-04-12 | Seinajoen Kylmakone A ja T Saikkonen Ky | Process for recovering contaminants from gases |
US4744910A (en) * | 1986-04-22 | 1988-05-17 | Voyager Technologies, Inc. | Electrostatic filter |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2974747A (en) | Electric precipitators | |
US1325124A (en) | Process and apparatus for precipitating matter from gases | |
DK168903B1 (en) | Ion generating apparatus and its use | |
JPS6346265B2 (en) | ||
JPS63503180A (en) | Arrangement for generating electric corona discharge in the air | |
GB816342A (en) | Improvements relating to silent electric discharge apparatus | |
JP2020179369A (en) | Air purifier | |
KR940005493A (en) | Ozone generator | |
JPH09503565A (en) | Electronic purification of exhaust gas | |
GB1204027A (en) | An electrostatic filter for the purification of gases and particularly of the air | |
US2127229A (en) | Process for producing large ions | |
KR20140085159A (en) | Air cleaning devices using atmospheric pressure dielectric barrier discharge | |
GB1157720A (en) | Tubular Ozonisers | |
US1839876A (en) | Apparatus or device for supplying artificially ionized oxygen for ventilation or other purposes | |
US1603279A (en) | Spark arrester | |
US3917470A (en) | Electrostatic precipitator | |
GB1340195A (en) | Separation and removal of selected gas components from gaseous mixtures | |
JPS63267419A (en) | Silent discharge generating device and gas treatment | |
JPS56160304A (en) | Ozonizer | |
US1975424A (en) | Air activator | |
KR20220056216A (en) | Device and method for ozone free separation of components in corona discharge zone | |
JPH0632259B2 (en) | Ionized gas generator | |
Uhrig et al. | Effect of operating rate on the arc duration of activated telephone relay contacts | |
SU678380A1 (en) | Device for samling aerosole from air | |
GB389237A (en) | Process of and apparatus for the electrical separation of suspended particles from gaseous fluids |