US2418339A - Gas purifier and sterilizer - Google Patents

Description

April 1,

1947. K; EHRGOTT GAS PURIFIER AND STERILIZER Filed Feb. 28, 1942 Emu El? INVENTOR ff I71? .E'A'EGG ATTORNEY Patented Apr. 1, 1947 GAS PURIFIER AND STERILIZER Karl Ehrgott, Baltimore, Md., assignor to West'- inghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 28, 1942, Serial No. 432,779

3 Claims.

This invention relates to means for purifying and sterilizing gas and, more particularly, to removing atmospheric dust and other impurities from air as well as sterilizing the same by killing bacteria and the like, said means being particularly, although not necessarily, used in the conditioning of air which is to be breathed.

The present invention is an improvement over that'described and claimed in the Penney patent, No. 2,129,783, of September 13, 1938, relating to a precipitator in which gas is blown, first through an ionizing chamber and then through a separate precipitating chamber, a significant feature of the precipitator being that the ionizing wire is of such small diameter that practically utilizable ionization of suspended particles in the gas may be obtained at a wire-charging voltage below the critical corona voltage, thereby limiting the ionizing current input, and ozone generation When the precipitator is used for cleaning air.

Such a precipitator utilizes an ionizing wire of less than 32 mils diameter, which is a somewhat critical value near the knee of the curve expressing the relation between critical corona voltage and wire diameter. The wire is preferably much finer than this upper limit and is desirably a tungsten wire approximately 5 mils or less in diameter. In order to insure against breakage and facilitate handling of the equipment, the end supports for such fine wire should be fairl rigid and strong, and if said wire is longer than about a foot, it should be supported at intervals along its length, say every 8 inches, in order to protect it against vibration, breakage and excessive saggmg.

An object of my invention is to introduce bac tericidal means into such a precipitator to sterilize the air passing therethrough, as by killing air-borne bacteria and the like.

Another object of my invention is to employ enerators of ultraviolet radiation of bactericidal character, which intersect or are disposed adjacent the precipitating plates, so that they not only sterilize air passing between said plates, but also irradiate the surfaces thereof and maintain the same in sterile condition.

Other objects and advantages of the invention, relating to the particular arrangement and construction of the various parts, will become ap arent as the description proceeds.

Referring to the drawing:

Fig.1 is a vertical, longitudinal, sectional view of one form of my invention, the section plane being indicated at I--I in Fig. 2.

Fig. 2 is a vertical, sectional view on the plane indicated by the line IIII of Fig. 1.

In the embodiment of my invention illustrated, air to be treated is drawn in through the top of the precipitator cabinet ll, through a protective screening I 2, and passes downwardly through an ionizing chamber l3 in the top of the cabinet, after which it continues and passes through a precipitating chamber, I4. A blower I5 is provided therebeneath for drawing the air through the apparatus. The outlet of the blower may either discharge the treated air near the floor, or the same might be led away in any desired manner.

The ionizing chamber l3, in the present embodiment, comprises a plurality of ionizing units disposed transversely with respect ,to the direction of the air flow, each unit consisting of a fine wire l6, which is desirably spaced midway between the relatively large electrodes ll, which are preferably tubular or curved in section so that they present convex surfaces toward the ionizing wire. As explained in the aforesaid Penney patent, the tubular electrodes I! are grounded on the precipitator cabinet II, and the ioniz ing wires it are suspended between rigid metal end supports I8 carried by-a skeleton frame work l9 which is supported by insulators 2 I.

The end supports l8 must be adequately spaced from the end walls 22 of the cabinet in order to provide adequate insulation. It will thus be seen that the air in the space between the end walls 22 and the supports [8 is not adequately ionized, and suitable baflle designated by the reference character 23, are therefore provided for keeping the air stream from passing over these regions of poor ionization. Unless the wires,

l6 are very short it will be usually found desirable to steady them at one or more intermediate points.

The precipitating chamber [4 consists of a large number of spaced insulated plates 24 and grounded plates 25 disposed close together and parallel to the direction of air flow. The insu lated precipitating plates 24 are supported by notched metal members 26 which are carried by insulators 21. The non-insulated plates 25 are supported and spaced by means of notched plates 28 carried by the cabinet I I.

As explained in the aforesaid Penney patent, the ionizing wires [6 and the insulated precipitae tor plates 24 are unidirectionally charged with respect to the uninsulated or grounded parts. Because of the greater spacing between each wire I6 and its associated tubular electrode ll,'as com the negative terminals being grounded onthe frame of the cabinet II, as indicated at 32.

In order to effect sterilization of the gas or air passing through the cabinet I I, while thesame is being freed of dust and other air-borne'particles, I provide apertures 33 and 34 in the plates 24 and 25 for the reception of a desirably U-shaped generator 35 of ultraviolet radiations of bactericidal character. This generator, in the present embodiment, consists of elongated tube of vitreous material containing electrodes 36 and 31 in end chambers thereof, and an ionizable-medium such as a mixture of neon and argon with mercury vapor. The vitreous material of the envelope is such that it transmits ultraviolet radiations of bactericidal character, that is those between 2500 and 2800 A. U., as well as some in the neighborhood of 1800 A. U. It is desirably constructed and operated generally as described in the James Patent, No. 2,258,765 of October 14, 1941, or corresponds with the ultraviolet discharge lamps or generators sold under the trademark Sterilamp by the Westinghouse Electric & Manufacturing 00., thereby cooperating with the ionizing means in avoiding the generation of an objectionable proportion of ozone.

For convenience inapplying the generator 35, the end walls of the cabinet H are desirably apertured, similar to the precipitator plates, and after passing the arms of the' U'-shaped generator through the apertures 33 and 34, the side wall apertures are desirably closed by a relatively shallow pan-shaped cover plate 38 at one end and a deeper pan-shaped cover plate 39 at the other end. The cover plate 39 carries sockets 4i and 42 for the generator 35, as Well as a transformer 43 to provide power atthe proper voltage for operation thereof, power leads to said transformer being indicated at 44 and 45.

,In operation, gas or air entering the top of the cabinet I I, as shown by the arrows, is first ionized in the chamber l3 so as to charge the particles which are suspended therein. The air then passes through the precipitating chamber l4 and over the arms of the U-shaped ultra-violet generating device 35 where charged suspended particles become attached to the oppositely charged precipitating plates, while it is at the same time treated by bactericidal ultraviolet radiations, whereby it is purified and sterilized; At the same time the surfaces of the precipitating plates and any collected particles are maintained in a sterile condition by the-ultraviolet radiations impinging thereon. The conditioned air is withdrawn from the cabinet by the blower l5.

When the precipitator, and especially the precipitating means, becomes dirty by reason of foreign particles extracted from the air, the ultraviolet generating device 35 is desirably first removed andthe remainder flushed out with a hose, after which it may be reassembled for use.

From the foregoing disclosure it will be seen that I have not only provided for removing particles :of dustland foreign'matter from gas-or air,

but have also provided for the simultaneous sterilization of said air, as well as maintaining the precipitating plates and any coating thereon in sterile condition, whereby my apparatus may be employed for air conditioning purposes in which it is desired to reduce or eliminate bacterial air infection as well as remove dust and other solid foreign matter. g

My present invention generallyfollows the practices explained in the aforesaid Penney patent, utilizing an ionization voltage considerably lower than the critical corona voltage, this practice being made possible by employing fine ionizing wire.

While I have described preferred embodiments of my invention, it will be understood that I am not limited thereto, as modifications may be made Within the spirit and scope of the appended claims.

I claim:

1. A gas purifying and sterilizing device comprising an ionizing chamber, a precipitating chamber, means for causing gas to flow successively through first said ionizing chamber and then said precipitating chamber, said precipitating chamber consisting of a series of closely disposed, spaced plates, alternate ones of which are at a potential dilferent from that of the ionization of the flowing gas, so as to attract solid particles in the gas passing therethrough, and means disposed insaid precipitating chamber for generating ultraviolet radiations of a bactericidal character, said means including an elongated ultraviolet transmitting envelope, said plates being apertured and said envelope passing through said apertures so as to extend substantially perpendicular to the planes of said plates. in order to direct radiation on the plate surfaces to maintain the same in sterile condition, as Well as sterilize the gas flowing therebetween.

2. A ga purifying an sterilizing device comprising an ionizing chamber, a precipitating chamber, means for causing gas to flow successively through first said ionizing chamber and then said precipitating chamber, said ionizing chamber being provided with one or more i0nizing units each disposed transverse to the gas flow and comprising oppositely charged electrodes, one of said electrodes being a single fine wire spaced between relatively large electrodes, said precipitating chamber comprising spaced, oppositelycharged plates lying substantially parallel to the direction of the gas flow, alternate plates being at a potential different from that of the ionizing wire so as to collect charged particles from the gas passing therebetween, and means disposed in said precipitating chamber and passing through apertures in said plates for generating ultraviolet radiations of a bactericidal character in order to direct such radiations on the plate surfaces to maintain them in sterilecondition and sterilize the gas passing therebetween.

v3 A gas purifying'and sterilizing device comprising an ionizing chamber, a precipitating chamber, means for causing gas to flow successivelythrough first said ionizing chamber and then said precipitating chamber, said ionizing chamber beingprovided with one or more ionizing units, each disposed transverse to the gas flow and comprising oppositely charged electrodes, at least one of said electrodes being a single fine wire spaced between relatively large electrodes, said precipitating chamber comprising spaced, oppositely charged, generally fiat electrodes lying substantially parallel to the direction of the gas a flow and one another, means associated with the ionizing chamber and the precipitating chamber for unidirectionally charging said electrodes, said wire being charged to a voltage which is below the critical corona voltage and of such fineness that practically utilizable ionization of the particles suspended in the gas is obtained, and means disposed in said precipitating chamber for generating ultraviolet radiations, a large portion of which lie between 2500 and 2800 A. U., in order that the same may be strongly bactericidal, said means consisting of an elongated ultraviolet transmitting envelope, said plates being apertured and said envelope passing through said apertures so as to extend substantially perpen- 15 KARL EHRGOTT.

REFERENCES CITED The following references are of record in the 10 file of this patent:

UNITED STATES PATENTS Number Name Date 2,271,792 Conant Feb. 3, 1942 2,218,190 Anderson Oct. 15, 1940

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