US2502137A - Apparatus and method for cleaning and humidifying gaseous fluids such as air - Google Patents

Description

March 28, 1950 w. FLEISHER APPARATUS AND METHOD FOR CLEANING AND HUMIDIFYING GASEOUS mums sucn AS AIR 5 Sheets-Sheet 1 Filed April 25, 1946 & m m w.

ATTORNEYS.

March 28, 1950 w. L. FLEISHER 2,502,137

APPARATUS AND METHOD FOR CLEANING AND HUMIDIFYING GASEOUS FLUIDS SUCH AS AIR Filed April 25, 1946 5 Sheets-Sheet 2 IH IHIH IH llllll IIHIIHIHHHI IHH llll Hill Illllllll! HI IHIH M NH llIl/IHH I HIIHIHIHHI lHlllHl'Hl H!! H in II! In! 1 H mm H IIIHHI IHH Hlli Illh ml II In NH! 11 mm up n m llllllillffl (Ill Hill Ill/Hill!!! ml! HIIIH HHI IH HHHHI/ll INVENTOR. WALTER L.FLEISHER Byadr I A T TORNEYS.

March 28, 1950 w, s E 2,502,137

APPARATUS AND METHOD FOR CLEANING AND HUMIDIFYING GASEOUS FLUIDS SUCH AS AIR Filed April 25, 1946 5 Sheets-Sheet 3 FIG.3.

Hun u Hun I II M Hll in NI H II Ill! H l l H! H [H H H! I II: II HH llllll II I H I llHllIHh H H) HII HI I|Hl|| H IH n I III II I \l I: In Ill FIGA.

7 mmvmn, WALTER L. FUIISHER ATTORNEYS.

March 28, 1950 w. L. FL APPARATUS 'AND METHOD FOR GASEOUS .FLUID 7 3 2 0 m I w I D M BR mu GS mmA Hmw smw E 5 Sheets-Sheet 5 Filed April 25, 1946 INVENTOR.

WALTER L. FLEISHER A TTORNEYS Patented Mar. 28, 1950 APPARATUS AND METHOD FOR CLEANING AND HUMIDIFYING GASEOUS FLUIDS SUCH AS AIR Walter L. Fleisher, New City, N. Y.

Application Apr-i125, 1946, Serial No. 664,744

9 Claims.

This invention relates to a method and apparatu for cleaning and humidifying air, i. e. for properly conditionin air in an enclosure during the entire heating season, and is a continuationin-part of my co-pending applications, Serial No. 549,668 filed August 16, 1944, now Patent No. 2,429,265 issued October 21, 1947 and Serial No. 618,438 filed September 25, 1945 now Patent No. 2,431,389 issued November 25, 1947.

A winter air conditioning system is a system which, in connection with any heating system, provides thoroughly cleaned air humidified within certain limits, a simple answer.

In the following, I shall attempt to describe briefly the inherent faults of the present day equipment and my endeavors to correct them.

Of more importance than merely clean air merely is the problem of adequate humidity. Adequate humidity in the home is essential, not only for the well being of the inhabitants, but for the proper care of woodwork, furniture, tapestry, books, etc.

Humidification is usually accomplished by evaporating water from a pan located on the bonnet of the furnace. This pan is frequently equipped with porous absorbent insets. The intermittent fiow of water to this pan is controlled by a float valve. Generally, it may be said that 95% of all existing winter air conditioning systems, or 95% of all such systems now being manufactured, consist merely of a fan with throw-away dry filters and a humidifying pan with a float valve. A thermostat regulates the operation of the furnace and a humidostat controls the humidity.

Dry filters require careful attention and changing during the heating season and their removal is always a dirty Job. Only too often the home owner has dispensed with these filters for good.

Wet filters of the type where water is sprayed over some sort of a porous mat are apt to cake up with lime and dirt because the sprays can function only intermittently in order to prevent overhumidification.

The conventional type of pan humidifier is definitely unsatisfactory. 9

Analysis of the faults inherent to the present winter air conditioning furnace, seem to furnish ample proof that heating or winter air conditionin equipment, must consist of a simple self cleaning air filtering system together with a method and apparatus meeting these requirements.

The employment of a concentrated triethylene glycol solution instead of water for the purpose of producing controlled humidification furnishes the answer to this entire problem.

Another important object of this invention is to provide method and apparatus for maintaining proper concentrations of triethylene glycol solution for conditioning of air throughout the heating season within a prescribed desirable range of relative humidities.

Another object of this invention is to provide simple and effective means for meeting these requirements.

Another and principal object of this invention is to provide apparatus for effecting the foregoing which obviates the usual controls and attention that must be given in present systems or apparatus in order to have them work economically and continuously throughout the heat ing season in various parts of the country where conditions vary from below 0 F., to 50 F. or F. and where the humidity varies greatly and where the hardness of the available water supply may be excessive.

To the accomplishment of the foregoing and such other objects as may hereinafter appear, this invention consists in the novel construction and arrangement of parts, hereinafter to be described in detaii and then sought to be defined in the appended claims, reference being had to the accompanying drawing forming a part hereof which shows, merely for the purposes of illustrative disclosure, preferred embodiments of the invention, it being expressly understood, however, that changes may be made in practice within the scope of the claims without digressing from the inventive idea.

In the drawing:

Fig. 1 is a sectional elevation taken along line ll of Fig. 2;

Fig. 2 is a sectional elevation taken along line 2-2 of Fig. 1;

Fig. 3 is a transverse section taken along line 3-3 of Fig. 1;

Fig. 4 is a diagrammatic sectional elevation of a modified form of construction;

Fig. 5 is a reproduction of a chart whose ordinates are equilibrium contact temperatures in degrees F., and whose abscissae are per cent triethylene glycol by weight; and

Fig. 6 is a diagrammatic showing of the application of the device for conditioning air in a house.

Referring to the drawing, in denotes a casing of suitable material that is provided with a gas or air inlet opening I I, preferably in its top, and

a gas or air discharge opening 12 in one of its sides at the lower portion thereof.

A water trough or dumping pan I3, preferably of trapezoidal section is loosely pivoted on shafts l4, it between sides of the casing it, so as to dump or tilt under the weight of a predetermined amount oi liquid therein in the clockwise direction of Fig. 1. Suitable abutments it, it extending from the face of casing it, restrict or limit the rotary movement oi a crank lever i8 fixed suitably to the pivot shaft H5. The limit stops it, ii are fitted with rubber or other sound-deadening material so that in making the dump and returning to normal position the sound of metal to metal between lever is and stops it, ii, is eliminated. These tops prevent over-travel of the dumping pan 58 during dumping 01 its contents so that it will always return automatically to the normal position shown in Fig. 1 after being emptied. In the embodiment shown, the dump tank is is adapted to dump when approximately two gallons of liquid have been delivered to it. This amount, however, is subject to variation as desired.

When the pan i3 is filled to its dumping capacity, it tilts in the clockwise direction of Fig. l and delivers its contents so that they strike a baffle plate 89 whence they fall upon the slightly sloping pan 20. In the embodiment shown, the slope of pan 2G is approximately per foot. Both the bafiie plate is and sloping pan 2d are suspended suitably within the casing iii. The distance between the baffle plate 119 and the discharge edge Ziia of the sloping pan 28 is so ad measured and the time required for the dumped liquid after it strikes baifle plate is to reach the discharge edge 28a is sumcient in relation to the viscosity of the dumped fluid to eliminate unevennesses of flow due to impact of the liquid upon the pan 28, so that substantially absolute uniformity of flow of such liquid over the discharge edge 20a is effected.

A screen or filter cell 26 is suspended angularly within the container or casing it at approximately 60 with the horizontal. The upper edge of this screen or filter cell 2i! is positioned to lie directly below the discharge edge 28a of sloping pan iii. The lower edge of the cell 25 extends downwardly and forwardly of its upper edge and rests, for example, on the bracket 22 supported from the casing it) so as to maintain the desired angular disposition oi said cell. This cell 2i, for example, has the construction of the cell of my ai'oremention Patent 2,356,757, granted August 29, 19M, or may have other suitable construction.

A second cell 23 is suspended within the casing Iii so that it and the cell iii in section have the appearance of an inverted V. To this end, the upper edge of cell 23 lies adjacent the upper edge of cell 2!, while its lower edge extends forwardly and downwardly and rests, for example, on the bracket 25 supported from the casing iii and disposed to maintain the angular disposition of cell 23 with respect to cell 2i so that the top or apex angle between the two screens 2! and 23 does not exceed 60. The cell 23 is preferably of similar construction to that of cell 2!, although it need not be as thick. It also may have other construction if desired.

A collecting member or pan 25 is secured suitably to the bracket 24. This pan extends the full width of casing in between its side walls and has a downwardly sloping portion 25a, a substantially vertical portion 25b and a collecting or sump portion 25c for a purpose to be presently described. This pan 25 also serves as a partitioning member or bai'fle to force the flow of gas or air from the inlet H through the cells or screens 2i and 23.

The collecting or sump portion 250 slopes downwardly toward one of the side walls of the casing in to a drain outlet 26 that delivers the collected fluid to a tank 21 supported suitably from the casing ID.

The tank 21 and the sump portion 25c in the embodiment shown have a capacity of approximately five gallons, that is, a larger capacity than is required for normal wintertime operation for reasons that will be presently described.

A suitable inlet conduit 28 is connected to a source of water supply (not shown) and the delivery of water to the tank 2i from said conduit is controlled by any conventional float operated valve 2% whose float 3b, in the embodiment shown, is positioned permanently to cut oil water supply to the tank 2? as long as its contents remain above a certain amount to be described. A pump st of conventional form, driven by a motor 32 is connected with the tank by conduit 33. The delivery conduit 3d of the pump extends upwardly from the pump, terminating in a nozzle 35 overlying the dump bucket 53 so that the liquid pumped from tank 27 is delivered to the said dump bucket or trough iii. If desired, conventional electric circuit connections can be provided to halt operation of the pump while bucket i3 is dumping although this is not essential to successful operation. A conventional drain out let 3%, normally closed by a valve 3i serves to remove the fluid from tank 2? for cleaning thereof or replacement.

The air to be conditioned is circulated by means of a suitable fan 38. This fan is positioned within the casing ii] on a frame 89 so that its discharge outlet 4t discharges air or gas through opening it in said casing. The suction inlets ii of the fan open into the casing iii so as to draw air or gas from casing inlet i i through the cells 2! and 23 and discharge it through opening 1! 2 after passing through the fan 38. The fan 38 is driven in conventional manner, for example, by a motor 42 coupled by belting 63 to a sheave M on the fan shaft 38a. Operation oi the motor is controlled by a conventional thermostat T. i

The liquid which is used in the conditioners of this application consists of a high percentage triethylene glycol water solution. The employment of a hygroscopic agent for the purpose of controlled humidiilcation, is novel in the industry.

With the aid of a chart embodied in this application (Fig. 5) on which there are plotted triethylene glycol water solutions equilibrium dew points in treating gases one can determine the concentration of a triethylene glycol water solution in equilibrium with any desired relative humidity at various contact temperatures. For instance, for a 35% R. H. (relative humidity) at 70 F. with a dew point of 41 F. the concentration of the triethylene glycol water solution should be 87.8% by weight.

Extreme humidities in the average home during the winter months should not be less than 20% and should not exceed 50 at 70 F.

I find that a relative humidity of 20% at 70 F. (28 dew point) indicates a 92% triethylene glycol solution and a relative humidity of 50% at 70 F. (505 dew point) indicates an 82% solution. From the chart of Fig. 5 it is apparent that triethylene glycol has a very flat curve of equilibother words, within this extremely narrow range of concentrations, 82% to.92%, lies the control of the extreme lower and upper limits of relative humidities that may be required in a residence during the winter heating season.

A typical example of the control which might be effected by this means in the average residence is the following. Assume a unit recirculating approximately 1,000 cubic ft./min. (c. f. m.) in 10,000 cubic feet of residential space. It is desired to maintain this space at a minimum temperature of 70 F. when the outdoor temperature is 33.3 F. and to maintain a relative hu midity of approximately 30%. (I have taken the outside temperature as 33.3 F. because it represents a fair average winter condition in certain sections of this country.) It is safe only to assume for average construction and usage that two changes per hour of actual air will be inflltered through the wall and cracks, admitted through doors in use, etc. This would amount to 20,000 cubic feet of air per hour or about 330 c. f. m. The room air, i. e., recirculated air taken back to the heater at 70 F. dry bulb (D. B.) and 30% R. H. will have a moisture content of 33 grains per pound. The infiltered air entering at 333 F. and at 85% R. H. carries only 23.5 grains per pound. In order to establish an average of 33 grains per pound of the air entering the space, the air passing through the condiditioner must pick up enough moisture to raise the infiltered outdoor air to 36.2 grains per pound. Theoretically, we should have the following conasoaisr l aroundthehousesothatthenewmethodlhave invented operates only when the fan is running except in solar as air inilltration is always V present. The-basisofmymethodis theuseof a solution of triethylene glycol and water of a very definite consistency which I have disture.

It must be remembered in considering this covered maintains over a whole heating season, seneral in the United States and in similar atmospheric environments, the required cleaning and humidiflcation'irrespective of the number of minutes per hour or per day that the fan runs to maintain the desired dry bulb temperainvention that. depending on the insulation and storm sashing of a house, the warm air system operates not over one-third of the time; the period of operation also varies with the outside temperature and the wind velocity. The relative humidity that is desirable in the house is about 25% to 40% as determined by various authorities, and the amount of fresh or outside air that combines with the air brought back from the house for reheating and then reconditioning and mixing is about 25%, most of which leaks into the house through doors, windows, etc. and is mixed in the house itself and is heated to room temperature by the heated air so that all the air comes back for recirculation and reheating at about room conditions or normally in the United States of America at about 70 F. to 72 F. in the winter time.

Now if a sloping screen at over which water is dumped is used as a filter, such as the screen or cell mentioned in my lPatent No. 2,356,757, and air is drawn through this filter screen 25 for one-third of the heating period and 25% of this air is outside or untreated air and 30% to R. H. is the greatest amount of relative humidity desirable and 72 is the desired dry bulb temperature, then the room condition should be a condition corresponding to 54 W. B. If only 25% of the air has to be humidified but all the air passes through a water-wetted screen even ditlons entering and leaving the conditioner: 5 with the low saturating emciency of my thin halv- Entering Leaving D. B. W. B. R. H. GrsJLb. D. P D. B. W. B. R. H. Grs./Lb. D. P.

Degrees Degrees Per cent Degrees Degrees Per cent The concentration of the triethylene glycol solution required for this condition is 87.8%. taken from the Fig. 5 chart of this application.

On a saturation efliclency basis, leaving conditions are as follows:

Grs. r D.B. W.B. 11.11. f 1).

The concentration of the triethylene glycol solution required for this condition is 85% taken from the chart reproduced in this application.

This invention relates to such forced warm air systems in which the temperature in the house is controlled by the starting and stopping of the fan (whose motor is connected in a thermostat circuit) which forces the heating air screen 2|, of say 40 to 60% saturating efliciency, enough water has been shown by experiment to be evaporated in the operating period of the fan 33 to raise the humidity of the average house to a point where water condenses out and runs down the walls and windows. If by some means (say by means of a hydrostat) the water dumped over the screen is turned ofi, the filter becomes very ineflicient as a dust and dirt arrester. Then.

it hard water is used (that means high in CaCos or Mg C03) caking takes place.

issued October 21, 1947 and November 25, 194! respectively, without regard to the time element to produce controlled humidification, highly efllcient continuous dust and dirt removal as a filter. and lubrication of the float mechanism to insure renewal of water evaporated, and absence of incrustations due to the deposit of the carbonates on the filter surfaces.

I am aware that triethylene glycol has been used as a dehumidifier and that in dilute solution it has allowed evaporation to take place, but the idea of controlled humidification in the method as proposed by me is new and novel.

The 1,000 C. F. M. unit of Figs. 1-3 inclusive of this application is charged with 32 pounds of a triethylene glycol solution. The sump 25c and tank 21 in the conditioner are large enough to hold approximately 50 pounds. The float valve 30 is so installed in this reservoir that with the tilt bucket l3 full and on the verge of spilling it is ready to open and admit water. Consequently, if by evaporation the level of the triethylene glycol water solution drops, the valve will open just before each tilt and admit sufficient water to restore the liquid level to its proper height. In this manner, the amount of water contained in the triethylene glycol solution is kept constant at all times provided, of course, that no triethylene glycol is evaporated.

In order to properly flush the sloping cell 2!, approximately two gallons of solution is required. Due to the nature of the setting of the float 30 and the fact that the dumping is not dependent on the pumping but purely on the balance of the tilting bucket 65, during this entire heating cycle the flushing is uniform irrespective of the slight change in the concentration of the solution. However, the system is designed to have sufiicient triethylene glycol per thousand cubic feet of air per minute circulated so that with an efliciency of 65% the amount of triethylene glycol per thousand cubic feet would be-through this particular cycle that I have indicateddecreased by only 0.528 pound per 100 hours of continuous operation.

Assuming 65% saturation ejficiency Per cent Tri- 60 F. 05 F. 70 F. ethylene Vapor Vapor Vapor Glycol Sol. Loss Loss Loss A 1,000 C. F. M. unit charged with 32 pounds of an 87% triethylene glycol solution would vaporize at 70 contact temperature approximately .00528 pound of triethylene glycol per hour (.ossx 00,000

or .528 pound per 100 hours that I provide a small additional container 00 filled with concentrated triethylene glycol and so attached to the unit that at each time when the dump bucket 36 tilts any desired quantity of triethylene glycol is released into the system. Other means might be employed actuated by the movement of the fan or the float, if desired.

In the embodiment shovm, the container is supported suitably from the casing 90. This container has a restricted outlet orifice til which normally is closed by a cover 02 which is suitably pivoted at 63 and actuated by a spring 00 that normally tends to make the cover E32 close the orifice 66. A sealing gasket 65 may be attached to the cover 02. An extension 00 of this cover is positioned so that an adjustable member 6? thereon lies in the path of travel of the lip 03' of the dumping pan iii as the latter nears its final tilted position which is regulated by the abutment ll. Thus, each time the dump pan i3 tilts to dumping position, it temporarily opens cover 82 and permits a limited amount of the triethylene glycol within container 60 to pass out for mixture with the dumped solution to replenish the small amount of the triethylene glycol lost by evaporation. The amount of added triethylene glycol can be regulated by the size of orifice 0i and by the position of adjustable member 6?. Cover 62 is closed by spring 6 except for the short period while edge l3 engages member fill.

From a chart of triethylene glycol properties, for example, chart No. G. C. 13 published by Carbide it Carbon Chemicals Corporation, 30 East 42d Street, New York, N. Y., it can be found that with average operation for a heating season with a contact temperature .528 pound of glycol would be evaporated at the end of one hundred hours. If in conjunction with my method of operation a supplementary container 00 of concentrated triethylene glycol is placed with respect to dumping pan It so that each time the bucket l0 dumps a drop or a regulated amount of triethylene glycol is released, the concentration can be maintained at the right amount throughout the entire period that the supplementary supply lasts. As it can be seen from the table just above, within the limits that I have set of 92% and 82% the entire quantity of tri ethylene glycol evaporated would probably not exceed 6 pounds for an entire season. As the dump bucket 06 only operates when the pump 3i operates and as the pump 3i only operates when the fan 33 is moving and as evaporation of triethylene glycol only takes place during the time that the fan 33 is blowing air through the contact screen 2!, no triethylene glycol would be dropped from the container 50 except when it was being evaporated on screen 2i. Consequently, the means of maintaining the triethylene glycol concentration between the two critical percentages of 82-92% discovered by me and called for in this specification would automatically be cared for without the possibility of overconcentration. As the supplementary container 60 could either be of glass or of such a design that the quantity therein was easily discernible and if more than its contents were required for a heating season, it could readily be supplemented without in any way stopping the system or removing from the system any of its parts. The combination, therefore, of the critical concentration of triethylene glycol and its relationship to the operation of a heating system and its supplementing automatically, but without exte- 9 rior apparatus, to maintain a concentration within the required limits for the desired winter conditioning and heating is part of this invention. The conditioner in its container I is placed .ahead of the furnace F, the conditioner inlet ll being connected to a conduit 50 leading to room air and also via conduit 50a to outside air, and the conditioner outlet I2 being connected by conduit 5| to inlet 52 of the furnace F whose outlet is connected by conduit 53 to supply air to room or rooms R of house H, (see Fig. 6). Conventional dampers in conduits 50 and 50a control the air flow toinlet II. The water is evaporated at temperatures ranging from 60 to 80 F. Whenever the fan 33 operates and air passes over and through the contact cell 2| a fairly large amount of water-one gallon or more-is washed over and through the cell; this takes place at from 3 to 3 /2 minute intervals. The triethylene glycol solution is washed into the tank 21 which holds approximately four gallons and while the solution is recirculated and only the evaporated portion of water is replenished with fresh water it can readily be seen that even when using plain water instead of triethylene glycol solution calcium and magnesium salt concentration can be built up to a considerable extent before lime forms on the cell or interferes with the action of the float valve. This, of course, is due to the large quantity of solution which is contained in the sump. With a triethylene glycol solution from 82% to 92%. such as is used in the conditioner of this application, the lime formation does not occur even when extremely hard water is used.

The cleaning of the air is accomplished with the aid of two filter screens 2| and 23: the contact cell 2| which also serves as the evaporator or humidifier and the eliminator mat 23 which has been added to the system in order to prevent entrainment and carry over of the triethylene glycol solution. Both of these cells or screens 21! and 23 are good and efiicientcleaners even when only plain water is used in the system. The cleaning efficiency of the mat 23 has been found to be 98.1%. The cleaning efficiency of the contact cell 2|, using plain water, is considerably less. This is due to the construction of this cell which was designed for a comparatively low saturation efliciency-an efficiency not to exceed 65%. However, the use of triethylene glycol solution in the system considerably improves the cleaning characteristics of the contact cell 2i. The viscosity of triethylene glycol is responsible for this.

The hygroscopic nature of triethylene glycol has an added advantage. This has to do with the extremely simple procedure of cleaning the system at the end of the heating season. The dirt and dust held in the cell 2 I, on the underside of the contact mat 23 or remaining in other parts of the unit, such as the tilt bucket it of the sump 25 exists in the form of a sludge, the liquid part of which is the highly hygroscopic solution of triethylene glycol. Consequently, when the system is being flushed out with water this type sludge, contrary to dirt and dust formed into a solid cake after evaporation of the water, readily liquifies and is easily drained from the system.

When the water, or a combination of water and a viscous fluid such as triethylene glycol, is dumped periodically over the upper part of a sloping filter screen such as a glass filter, where purposefully certain portions of the liquid flow down the filter or screen for cleaning purposes and other portions pass through the filter or screen for wetting and partial humidification of the gas passing therethrough, some of the liquid, because of its viscosity and surface tension tends to form itself into minute spheres in the nature of tiny hollow bubbles. These bubbles being very light, are carried along in the air stream and are not taken out by conventional eliminators or hooks, which are commonly an integral part of a washer or scrubber eliminator, and where the specific gravity of the ordinary water droplets is sufilcient for the velocity of discharge to throw the droplets against the surfaces of the eliminator plates. With the tiny viscous bubbles which are developed with a solution such as the solution herein described, there is no tendency for the bubbles to be thrown out of the air stream and consequently a screen having only the finest interstices (such as the filter screen described in Patent No. 2,356,757 or one of similar construction) is efiective for the purpose, and even a screen such as this, unless set at the angle herein described, will not effectively remove these bubbles, which are not in the nature of an evaporated vapor.

In the case, for example, where the filter screens are similar to that disclosed in my U. S. Patent No. 2,356,757 or in my co-pending application Ser. No. 549,668, filed August 16, 1944. now Patent No. 2,429,265 issued October 21, 1947, or with other filter screens, I have discovered that if the second screen 23 similar in principle to the original filter screen or filter 2| is installed at an angle facing the original screen 2| and approximately at the same angle. the two forming an inverted V, the small bubbles or droplets which ordinarily would be carried over and emitted with the gaseous stream, are eliminated. These small bubbles or droplets are either broken into such small shattered fragments that they attach themselves to and follow the slope of the eliminating screens and are thus carried to the bottom of the screen and to the collecting pan, or else, by the eddy set up by the action of the gas or air stream, because of the angular position of the eliminating screen, are deflected back into the liquid in the collecting pan and Ehence drained into the liquid medium in the ank.

The velocity of the gas or air stream striking the eliminating screen 23 is of maior importance. At the top of this screen where the gas velocity is greatest, because the distance between the leaving surface of the filter 2| is closest to the entering surface of the leaving eliminator 23, the eddies created are so strong that they have a tendency to immediately carry the drops or bubbles floating in the gas or air stream away from the entering face of the eliminator 23 to prevent the bubbles or drops from even coming in contact with said face. Also, due to the velocity over this upper surface, I have discovered that an induced current is developed which has a tendency to keep these droplets away from the surface of the leaving screen 23 until they can be absorbed or deflected. In the lower portion of the leaving screen or eliminator 23 where the velocity of approaching gas or air is less, the bubbles or droplets have an opportunity to settle and cling to the face of the eliminator screen 23, and are then by gravity or gas or air movement carried to the bottom of the screen 23 and then carried off to the collecting pan 25.

If the eliminator screen 23 were not disposed angularly as indicated, namely, so that it and the ii. filter screen 2 l form an inverted "V", the structure in section approximating an isosceles triangle with the top apex angle not exceeding 60 degrees, the tendency would be for the droplets to settle on the eliminator screen 23. They then would eventually work themselves through the latter to again be carried by the emerging air or gas stream as unvaporized droplets. The latter would then become deposited on walls, furniture and ceilings and throughout the ducts and associated apparatus. It is extremely important that this should not occur because the viscous or controlling liquid is expensive and its loss by deposit would require replacement. Moreover, this deposited material would create an undesirable sticky scum on the walls, furniture, ceilings, ducts and associated apparatus. Although these droplets are minute in their individual entities, they constitute a far greatenweight of the viscous material than is actually evaporated and purposefully carried through the leaving screen with the air stream. Consequently, although there is some danger of the vaporized solution eventually depositing out, it is so minute that it is of no importance, but, if the droplets or escape or have a tendency to escape, the effect would be undesirable. Except in true vapor form, none of the conditioning liquid must leave the apparatus. The eliminator screen 23 and its arrangement relative to filter screen 2| obviates such an occurrence.

Because of the cost of the triethylene glycol, it is essential to conserve and re-use the latter for an indefinite period of time. Consequently, the solution which is dumped over the sloping cell or screen is collected on the sloping plate 25a and in sump 25c underneath the screen and drained into the tank 21. The sump 25c and the tank 21 together must be designed in accordance with this invention to hold from one-and-a-half to twice the volume of the basic viscous liquidthat is, the triethylene glycol or similar liquid chemical. This is an extremely important aspect of this invention. The importance can be understood from a consideration of the operations resulting from use of the apparatus.

If the dumping pan l3 or similar equipment holds two gallons essential for proper flushing of the cell or screen 2|, then for winter use the tank 21 must hold at least four gallons of solution so that two gallons can be drawn by pump, 3| from this tank and discharged into the dumping pan |3 through conduit 34 and discharge nozzle 35. In the tank 21 which contains the total volume of solution, the float 30 is positioned to.

cut an water delivery at the level of the remainder left'in the tank 21 after the dumping volume (two gallons in this embodiment) is withdrawn. If-

water is evaporated during the period after a dump, then on the next filling of the dumping tank I3 the level remaining in the sump 25c and tank 21 will be reduced below the cut-off level of the float 30-and water will flow into the tank 21 to replace the evaporated water. As the chemical. such as triethylene glycol or similar viscous material, is minute in its evaporative charactercloses as soon as the float 30 rises to its cut-oil level.

However, as the float control valve 29 is set permanently at the winter level, the summertime level in the tank 21 always remains above the cut-off level of the fioat Sll and no additional water will be supplied to the solution during this period. In this way, by having the tank 2? designed for the variation in the vapor pressure characteristics of the particular solution, definite humidities can be maintained during the artificially created heating season, and safety factors for the saving of the solution can be maintained during the free. or mild season. In this way, the simplest type of control of humidity is maintained over a wide period of the year without thermostatically sensitive instruments, which respond to the moisture content of the air.

The principles disclosed can be adapted for use with a multiple cleaning and humidifying apparatus as is illustrated digrammatically in Fig. 4. Therein the sumping trough i3 discharges its contents to deliver the conditioning liquid to the filter screen 2|. The liquid drained therefrom and the eliminated bubbles or droplets from its eliminator screen 23' are caught on the drain pan 25'. This pan 25' is controlled by a weighted gate 50. When the liquid collected in the sump portion 25c of the pan 25 overcomes the weight 5|, the sump contents are dumped to cascade over the second filter screen 2|". The liquid drained from the latter screen and the eliminated bubbles and droplets from its eliminator screen 23" are caught on drain pan 25". This pan is likewise controlled by a weight-operated gate 50'. When the liquid collected in sump portion 25"c of the pan 25" overcomes weight 5|, the sump 0 contents are dumped to cascade over the next succeeding filter screen 2|"' also having associated with it an eliminator screen 23". Ultimately the residual liquid is returned to a collecting tank for repumping to the original dump trough l3. It will be noted that each filter screen and its associated eliminator screen forms an inverted V whose apex angle does not exceed 60. The number of such sets of inverted V's can be as desired. The same auxiliary container 60' and operating parts can be provided and operated by bucket l6 to replace evaporated triethylene glycol. The principle of operation whether a single set or multiple sets are used is the same as that described for the single set of Figs. 1-3 inclusive.

The apparatuses decribed may be used directly for conditioning a room or enclosure. They may also, for example, be used in conjunction with heating systems, such as warm air heating systems. When so used, the casings III or ID and their contents may be positioned adjacent to the hot air furnace. An air inlet conduit 50 for leading air from the room of the house is connected to the inlet II or II' of casings l0 or III. The delivery outlets l2 or I2 of the casings are connected by a conduit 5| to the air inlet 52 of the furnace so that conditioned air from the device of the invention is delivered to the furnace, heated therein and from the latter is delivered by conduits to the room or rooms of the house. Ordinary heating or cooling coils (not shown) such as those used for hot water or steam heating can be inserted in the discharge outlet l2 from the fan and the apparatus used, therefore, for any type of heating.

Other hygroscopic materials may be used provided they have similar characteristics as those inherent to triethylene glycol. For instance, they may be those mentioned in my said other application. or such materials may belong to the group hydroxyl (OH) group introduced into a glycol results in a product in which its qualities of absorbing or releasing water vapors from or into the atmosphere, according to the existing relationship between the moisture content of the material and the relative humidity is enhanced. Usually the boiling point of such products is raised approximately 100 C. and its rate of evaporation is correspondingly decreased. Any products of this or similar type may consequently be used to advantage in connection with this invention.

While specific embodiments of the invention have been disclosed, it is to be understood that changes may be made in practice and are contemplated. The size and dimensions of the devices are not to be construed as limited to those described as they may be varied in practice to suit different operating requirements. There is no intention of limitation to the exact details shown and described.

What is claimed is:

1. In apparatus of the character described, gas cleaning and humidifying means, periodically operable dumping means for supplying viscous conditioning liquid consisting of a solution of water and a hygroscopic material to said first-named means, means for circulating the gas to be conditioned through said first-named means, means for replenishing the water evaporated from said solution, and means responsive to operation of the dumping means for automatically r-eplenish ing the hygroscopic material evaporated from said solution.

2. Apparatus of the character described for conditioning a gaseous fluid such as air in an en-- closed space wherein it is largely recirculated to clean and humidify it to prescribed humidity and dry bulb temperature comprising filtering means, means for circulating said fluid therethrough, means for intermittently dumping upon said filtering means a solution of water and a hygroscopic material of prescribed concentration, means for replenishing water evaporated from said solution and means responsive to operation of said dumping means for replenishing hygroscopic material evaporated from said solution to maintain said prescribed concentration of said solution.

3. Apparatus of the character described for conditioning a gaseous fluid such as air in an enclosure wherein it is largely recirculated to clean and humidity said fluid to prescribed humidity and dry bulb temperature comprising filtering means, means for circulating said fluid therethrough, a reservoir for a solution of water and hygroscopicmaterial, a dumping tank, positioned to empty itself when filled to a determined level, means for pumping solution from said reservoir to said dumpin tank, means for delivering solution dumped from said tank onto said filtering means, means for collecting solution draining from said filtering means and returning it to said reservoir, means in said reservoir controlled by the level of solution therein for replenishing water evaporated from said solution, a reservoir for concentrated hygroscopic material, and means operated by said dumping tank in tilting to release a determined quantity of said concentrated hygroscopic material to the solution to maintain the prescribed initial concentration of said solution substantially uniform at all times.

4. A method for conditioning a gaseous fluid such as air under heating season conditions in an enclosure wherein it is largely recirculated for cleaning thereof and humidifying said fluid within prescribed limits of relative humidity at determined dry bulb temperatures, comprising circulating said fluid through a cleaning and humidifying element, wetting the element with a solution of water and triethylene glycol whose concentration of triethylene glycol lies within fixed limits of 82%-92% by weight of said solution, recirculating said solution repeatedly, automatically replenishing water evaporated therefrom during circulation and adding periodically concentrated triethylene glycol to replace triethylene glycol evaporated from the solution in quantities sufilcient to maintain substantially the initial concentration of said solution at all times.

5. A method for conditioning air under wintertime conditions in an enclosure wherein it is largely recirculated for cleaning thereof, for maintaining it at a dry bulb temperature ranging from 70 to 75 F. at a relative humidity not less than 25% nor more than 50% comprising the steps of circulating air drawn from said enclosure through a cleaning and humidifying element and then through a heater and back to said enclosure, wetting said element with a solution of water and triethylene glycol whose concentration of triethylene glycol is not less than approximately 82% by weight nor more than approximately 92% by weight of said solution, recirculating said solution repeatedly, automatically replenishing water evaporated therefrom durin circulation and adding triethylene glycol to replace triethylene glycol evaporated from the solution in quantities sufiicient to maintain substantially the initial concentration of said solution at all times.

6. Apparatus of the character described for conditioning air under heating season conditions in an enclosure wherein the air of the enclosure mixed with air infiltrating from outdoors is largely recirculated for cleaning thereof and humidification within limits of relative humidity ranging from not less than 25% to not more than 40% at dry bulb temperatures of approximately 70 F. to approximately F. comprising a filter element, heating means, means for circulating the air from said enclosure through said element and through said heating means back to said enclosure, a reservoir for a solution of water and triethylene glycol whose concentration of triethylene glycol by weight lies between 82% and 92%, a dumping tank adapted to tilt and dump when a fixed quantity of said solution has been delivered thereto, means for delivering solution to said tank, means for directing solution dumped from said tank onto said filter element, means for returning dumped solution draining from said element to said reservoir, float means in said reservoir operative at a determined level of solution therein to admit water to replenish that lost from said solution by evaporation, an auxiliary reservoir for concentrated triethylene glycol, and means operated by the tilting of said tank for admitting concentrated triethylene glycol of a determined quantity to said solution to replenish triethylene glycol evaporated from the solution to maintain substantially the initial concentration of said solution at all times.

7. A method for conditioning a gaseous fluid such as air under heating season conditions in an enclosure wherein it is largely recirculated for cleaning thereof and humidifying the fluid within prescribed limits of relative humidity at determined dry bulb temperatures, comprising circulating said fluid through a cleaning and humidifying element, wetting the element with a solution of water'and triethylene glycol whose concentration of triethylene glycol lies within approximately 82% to approximately 92% by weight to evaporate water from said solution into said circulating fluid and triethylene glycol from said solution into said circulating fluid to maintain a relative humidity in said fluid of approximately 30% to 35% and to vaporize approximately 0.528 lb. of triethylene glycol for each one hundred hours of continuous passage at 1000 cubic feet per minute of said circulating fluid through said element at approximately 70 E1, recirculating said solution repeatedly, automatically replenishing water evaporated from said solution during circulation'of said fluid and adding concentrated triethylene glycol to replace triethylene glycol evaporated from the solution in quantities sufllcient to maintain said concentration within the range 01 approximately 82% to approximately 92% by weight.

8. A method for conditioning air during the heating season of a year in an enclosure wherein it is largely recirculated for cleaning thereof and for maintaining it at a dry bulb temperature ranging from 70 to 75 F. at a relative humidity not less than 25% nor more than 50% comprising the steps of circulating air drawn from said enclosure through a cleaning and humidifying element and then through a heater and back to said enclosure, providing a reservoir for triethylene glycol whose capacity is in excess of that quantity of said glycol required for use during the heating season, wetting said element with triethylene glycol withdrawn from said reservoir together with water in a solution whose concentration of triethylene glycol by weight during the heating season ranges from approximately 82% to 92%, recirculating the solution repeatedly, and automatically maintaining the concentration of the solution within said percentage ranges throughout the heating season by the absorption of water hygroscopically irom the air and water automatically added in response to departures from a determined level of liquid in said reservoir.

9. A method for conditioning air under wintertime conditions in an enclosure wherein it is largely recirculated for cleaning the air, for maintaining it at a dry bulb temperature ranging from to F. and at a relative humidity not less than 25% nor more than 50% comprising the steps of circulating the air drawn from said enclosure through a filtering screen wetted with a solution of water and triethylene glycol whose concentration of triethylene glycol by weight ranges from approximately 82 to approximately 92%, automatically maintaining said concentra-= tion of said solution. delivering the said wetting solution to said'screen to provide a flushing action thereby to clean the screen of filtrate accumulating thereon as a result of passage of the air circulated therethrough, subsequently ridding the air leaving said screen of any entrained droplets of said solution and then passing the air through a heater and back to said enclosure.

WALTER L. FLEISHER.

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

UNITED STATES PATENTS Number Name Date 871,194 Thomas Nov. 19, 1907 1,791,086 Speer, Jr "Feb. 3, 1931 1,846,875 Karr et al Feb. 23, 1932 1,952 406 Barstow et al. Mar. 27, 1934 2,137,996 Crawford Nov. 22, 1938 2,431,389 Fleisher Nov. 25, 1947 FOREIGN PATENTS Number Country Date 515,502 France Nov. 26, 1920

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