US2990911A - Means to indicate shorting of precipitator by collected material - Google Patents

Description

July 4, 1961 H. s. LIPPINCCTT MEANS TO INDICATE SHORTING OF PRECIPITATOR BY COLLECTED MATERIAL Filed Sept. 12, 1957 W T M MM M T/ 6 m H B V. i m 4 7 .w E/ JM i. 3) W F United States Patent 2 990,911 MEANS T0 INDICATE SHORTING 0F PRECIPI- TATOR BY COLLECTED MATERIAL Holland S. Lippincott, Riverton, NJ., assignor to Philco V Corporation, Philadelphia, Pa., a corporation of Penn sylvania 7 Filed Sept. 12, 1957, Ser. No. 683,554 2 Claims. (Cl. 1837) The present invention has to do with indicating means, and more particularly to means for visibly indicating the performance of electrostatic precipitating apparatus of the type used for cleaning air within a habitable enclosure.

It is known that operation of electrostatic precipitating devices is characterized by the presence of relatively high voltages. Accordingly, and in order to ensure safe operation of air cleaning means comprising electrostatic precipitators of the portable type, as well as, for example, the type utilized in combination with window mounted air conditioners, it is important to include various safety features designed to protect users of such apparatus from the aforementioned relatively high voltages associated therewith. Further, it is to be noted that since operation of an electrostatic precipitator is substantially noise-free, andin the absence of moving parts in such apparatus, a user may be unable readily to determine whether or not the precipitator is operating, or even to distinguish between faulty and normal operation thereof; also in certain electrostatic precipitating apparatus it is necessary that the user periodically clean or replace dust collector elements comprising electrodes of the high voltage electrical circuitry, and it is imperative that means be provided for warning the user of the presence of hazards, in the event of malfunctioning of conventional interlock means provided for deenergizing the apparatus upon disassembly of the same.

Heretofore, no simple, reliable and positive means for indicating the condition of operation of such equipment, in these important respects, has been available. It is, accordingly, the general object of this invention to provide a novel electrical circuit comprising but a single visible indicating means for indicating that the precipitator is operating, that the collecting electrodes, or filters, have become dirty and are in need of replacement, and that the electrical interlock apparatus is operating properly.

It is an additional object of the invention to provide in electrostatic precipitating apparatus visible signaling means for indicating presence of a shock hazard.

A still further object is to provide signaling means of the foregoing type which has a useful life of long duration and requires a minimum of care on the part of the user.

In the achievement of the foregoing and other objects and advantages, a preferred embodiment of the present invention comprises, in combination with an electrostatic precipitator, signaling or indicating means including a glow-discharge lamp disposed in novel and suitable electrical circuitry with an electrode of the precipitator. The invention, in an important aspect thereof, contemplates locating the lamp in series electrical circuitry with the discharge and collecting electrodes of so-called single stage precipitator apparatus, the latter being characterized in that the aforesaid electrodes cooperate to provide a combined ionizing and collecting field.

The novel features of the invention, and the manner in which the foregoing and other objects and advantages are best achieved will be apparent from the following description taken in view of the accompanying drawing, in which:

FIGURE 1 is a perspective showing of a window mounted room air conditioner made in accordance with a preferred embodiment of the invention;

FIGURE 2 is a view similar to FIGURE 1, but showing a portion of the housing structure removed;

' FIGURE 3 is a somewhat enlarged fragmentary sectional view of the apparatus shown in FIGURE 2;

FIGURE 4 is a further enlarged fragmentary view of apparatus shown in FIGURE 3;

FIGURE 5 is an enlarged fragmentary view, in elevation, of apparatus shown in FIGURE 2; and

FIGURE 6 is a schematic showing of the electrical circuitry of precipitating apparatus embodying the invention.

Prior to a detailed description of the novel apparatus in light of the accompanying drawing, it is pointed out that for purposes of illustration the present invention is embodied in combined filtering and refrigerating apparatus of the type dis-closed and claimed in the copending application of Robert G. Kurtz, Serial No. 647,540, filed March 21, 1957, now US. Patent 2,933,151, and assigned to the assignee of the present invention.

Now making more detailed reference to the drawing, and particularly to FIGURE 1, the-re is shown a conventional window mounted air conditioner 10 including a cabinet 11 and a conventional decorative panel 12. Disposed in the decorative panel are the inlet and outlet air grilles 13 and 14, respectively, each being in air flow communication with the usual refrigerating and air moving means (not shown) housed within the air conditioner cabinet.

Shown in FIGURE 2 is air conditioner 10 with the decorative panel 12 removed to expose electrostatic filtering and ionizing means 15 in novel combination with indicating means, designated generally by reference numerals 15a, with which this invention is concerned. In accordance with the embodiment illustrated, the construction and arrangement of the filter 15 is such that it is disposed intermediate the inlet grille 13 and the inlet air duct 17 of the air conditioner. There is also shown in FIGURE 2 a suitable electrical component structure or pack 16, 16a, including cycle controls, indicated at 18 and 18a as well as ionizing voltage supply means 19. Additionally, there is provided suitable interlock switch means 1812, which in the embodiment illustrated comprises a push button switch operably engageable with decorative panel 12, selectively to deenergize or energize voltage supply 19, in response, respectively, to removal or installation of the latter. Additionally, there is provided a suitable manually operable switch for selectively deenergizing and energizing voltage supply 19. Access to the above mentioned switch 18c and controls 18, 18a, as well as indicating means 15a, is accommodated by a suitably hinged cover 12a provided in the panel 12.

Now referring again to FIGURE 2, there is shown filtering and ionizing means 15, including a sleeve-like housing 20 provided with a suitable detachable cover 20a. As seen in FIGURE 3, cover Zlla has been removed thereby providing access to the filter elements to be hereinafter more fully described. Attachment of filtering means to the air conditioner may be made in any suitable manner, and it is seen in FIGURE 3 that the preferred embodiment contemplates the simple expedient of attaching housing 20 by screws 22 passing through flanges 21 thereof and into the air conditioning cabinet 11. Additionally seen in FIGURE 3 are upstream and downstream impingement type filters-or collector electrodes 23 and 23a, preferably of metal construction and including coatings of viscous material (not shown). The filter illustrated comprises a filter medium 24 of several layers of expanded aluminum sheet supported Within an aluminum frame 25. Serving further to rigidity the frame 25 are diagonal cross members 26 which are attached at the corners of the frame by known suitable means.

Retaining means for filters 23 and 23a include guide channels 27 comprising flange portions 28 and 28a of housing 20, and edges 29 of an insulating frame 30 (to be hereinafter more fully described), said channel being adapted slidably to receive the filters for removal and insertion thereof. Disposed in one of the aforementioned channels 27, preferably although not necessarily the upstream channel, is an insulating member 27a comprising an L-shaped sheet of suitable material which serves elec trically to insulate frame 25 of metal filter electrode 23 from the housing 20 for reasons to be hereinafter more fully explained.

Referring further to FIGURE 3 there is seen an electrode 32 supported in a serpentine manner by frame 30 which is electrically non-conductivein vertically extending parallelly disposed spans lying substantially in a plane extending transverse the direction of air flow.

Immediately downstream of the second metal filter 23a is a charcoal filter 35 adapted for slidable insertion into or removal from channels 36, much in the manner of filters 23 and 23a. Insertion and removal of the foregoing elements is accomplished through the mentioned top access opening provided in housing 20, as best seen in FIGURE 3, and with the cover 20a removed. Additional structure includes wire screens 37 aflixed to the inner faces of the filters 23 and 23a. These wire screens insure proper spacing of the filter media 24 from the ionizing wire 32, inasmuch as metallic filter media of the type illustrated is sometimes flexible and movement thereof may upset the substantially critical spacing between the ionizing wire and the collector electrode.

A tensioning means 40 comprising spring 41 is aifixed at one end to suitably formed portion 42 of the web 38 and at the other end to clamping means 43 aflixed to wire 32. Enclosing the tensioning means 40 is a sleeve-like member 44 of electrically insulating material. Tensioning means 40 will advantageously compensate for variations in the length of wire 32 and therefore aid in maintaining proper spacing of the wire from the collector electrodes 23 and 23a by preventing undue sagging of the wire.

Suitable electrical terminal means (not shown) is associated with the ionizing wire to accommodate energization of the same by wire lead 46 (FIG. 6) to be hereinafter described.

In the channel member 27 adapted to receive the downstream collecting electrode 23a there is disposed a leaf spring 31a adapted resiliently to bear against the inserted electrode to retain the same and enhance electrical contact of the latter to grounded housing 20. There is further provided in the channel member 27, adapted to receive upstream filter 23, a leaf spring 31 adapted to bear against insulating member 27a which is thereby urged against an inserted filter 23, to retain the same.

In particular accordance with one aspect of the present invention, and as best seen in FIGURE 4, an aperture 20b is provided in housing 20, said aperture accommodating passage of wire lead 59a. Wire lead 59a is electrically connected to leaf spring contact 31b by means of eyelet 310, the latter serving also to mount contact 31b upon insulating member 27a. Thus it is seen that filter electrode 23 is electrically insulated from the grounded housing 20, and the sole electrical contact to the filter 23 is made through the above described contact 31b.

Now referring to FIGURE there is seen in detail the indicating means 15a shown in FIGURE 2, said means comprising a capacitor 15b and a lamp 150 of the type commonly known as a glow-discharge lamp. There is of course included known suitable bracket means B associated with structure 16a for supporting the capacitor 15b as well as known snap-action means S for holding the base portion of lamp in a suitable aperture provided in the aforementioned structure 16a. There is also provided associated electrical circuitry for incorporating the indicating means into the electrostatic filtering circuit, said circuitry including wire lead 59a, terminal means T for grounding leads 59b and 590, as well as connector D for joining leads 59d and 5% to 59a.

Now referring to FIGURE 6 of the drawing there is seen a schematic diagram of suitable electrical circuitry for producing the desired combined ionizing and collecting electrostatic field, in novel combination with the indicating circuit with which the present invention is concerned.

Transformer 55, the primary winding of which may be supplied, through interlock switch 18b and manual switch 18c, with electrical power from a suitable source, supplies a voltage, for example about 6000 volts, to a half wave rectifier tube 56, the same D.-C. voltage being impressed across ionizing electrode 32 and filter electrodes 23 and 23a. This voltage is maintained substantially constant by resistor 57 and corona discharge tubes 58, and condenser 60 provides means for maintaining peak voltage supplied by the rectifier tube 56. A resistor 61 is also provided as shown, to control the current through the electrodes 32 and 23, preferably limiting the current to a value of about 10 microamperes.

In particular accordance with the present invention, lead 59a extending from the spring terminal 31b contacting the electrodes 23 and 23a is connected to ground 59 through the glow-discharge lamp 150 and the capacitor 1511, the latter elements being connected in parallel as shown. Lamp 150 comprises a suitably encapsulated neon lamp of the type known commercially as Ne2, & watt, and capacitor 15b comprises a cylindrically formed .067 fd. condenser of known type.

Thus, the novel indicating means is disposed in series with a collecting electrode of the air cleaning and filtering apparatus. Disposition of the indicating means in the circuit is such that functioning of the high voltage elements, as well as the apparatus preceding the same will be indicated.

In preferred operation of such a combined filter and ion generator a negative potential is applied to the ionizing wire 32 whereupon electrostatic fields are set up between the ionizing vvire and the upstream and downstream filters, or electrodes, at least the former being grounded through the novel indicating apparatus 15a. Accordingly, a charge builds up on the upstream filter electrode 23, as well as on the capacitor. When the firing potential of the neon lamp 150 is reached, the builtup charge discharges to ground through the lamp, accompanied by glow of the latter. The aforementioned cycle is repetitive in nature, and the frequency of its occurrence will depend, for example, upon the value of the corona current existing at the ionizing wires. Such current may be a function, for example, of the presence of an excessive accumulation of particulate matter upon the electrode 23, this matter tending to bridge the insulating members 27a, 30 and housing 20, thereby electrically to ground the said electrode; particulate accumulation is therefore reflected in that a longer period of time is required to build up to the firing potential of the neon lamp 15c, to light the same. It is seen therefore that because the lamp is in series with the high voltage elements, excessive particulate accumulation is readily indicated. Thus, progressive fouling of filter 23 will be indicated by a diminishing frequency of light pulsation or flicker. In the event of component malfunctioning, the nature of the electrical circuitry is such that the lamp will of course cease to fire, thereby indicating a failure in the system, inasmuch as the necessary lamp firing potential will not be attainable. Finally safety of a user of the apparatus is ensured by visual indication of the presence of a shock hazard in the event the interlock feature should fail to deenergize the high voltage .ija

circuit upon removal of the panel 12. Thus, as will now be appreciated, complete operation of the air cleaner is indicated, and failure of any phase of its operation will be indicated by the device hereinbefore described.

Although, in the illustrated embodiment of the present invention, the novel indicating means has been disposed in series circuit with the upstream collector electrode 23, it is to be understood that the downstream collector electrode 231! may be disposed in like circuitry with the indicating means, either singly or in tandem with the upstream electrode 26.

While this description and the accompanying drawing are illustrative of a preferred embodiment of the invention, it will be recognized that changes and modifications may be made in the described apparatus, without departing from the scope of the appended claims. For example, there may be provided unitary indicating means 15a comprising the essential elements illustrated in FIG- URE 5, whereby the means 15a serves as a portable test instrument to use with precipitating devices not thus equipped. To this end, element 16w may comprise suitable insulating frame structure, and terminal T and lead 590! could be modified by affixing thereto leads provided with suitable known clip means for attaching to appropriate electrical components of a precipitator.

I claim:

1. In single stage electrostatic precipitator apparatus, a discharging electrode and a collector electrode consisting of an electrically conductive filter screen, means for applying a high D.-C. potential between said electrodes to create a combined particle ionizing and collecting field therebetween, and visibly pulsating indicator means operative over a range of pulse frequencies and including means for changing said frequencies in response to changes in the amount of particulate collection by said filter screen.

2. Precipitator apparatus in accordance with claim 1, wherein said indicator means comprises a capacitor and a glow discharge lamp arranged in parallel circuit and each disposed in series electrical circuitry with said filter screen and said means for applying a potential.

References Cited in the file of this patent UNITED STATES PATENTS 2,129,783 Penney Sept. 13, 1938 2,189,614 Penney Feb. 6, 1940 2,579,441 Palmer Dec. 18, 1951 2,738,443 Danziger Mar. 13, 1956 2,791,725 Williams May 7, 1957 2,798,572 Fields July 9, 1957 OTHER REFERENCES Article titled Novel Test Meter, in vol. 47, issue 4, page 42 of April 1952 issue of Radio and Television News.

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