US3378238A - Porous block humidification - Google Patents

Description

April 1968 R. s. BABINGTQN ETAL 3,373,233

POROUS BLOCK HUMIDIFICATION Filed July 15, 1965 49! INVENTORS iafiez'i ifiaa'rgyiw'a 5 .i ilgria er M M Ma,

ATTORNEYS United States Patent Office 3,378,238 Patentedl Apr. 16, 1968 POROUS BLOCK HUMIDHFICATIUN Robert S. Babingtou, 1113 Ingleside Ave., McLean, Va. 22067; Albert A. Yetman, 12316 Kemhridge Drive, Bowie, Md. 20715; and William R. Slivlra,

17 Shellflower Road, Levittown, Pa. 19056 Filed July 15, 1965, Ser. No. 472,178 8 Claims. (Cl. 261-26) ABSTRACT OF THE DISCLOSURE An air moisturizing apparatus comprising a porous mass mounted beneath the surface of a liquid reservoir, means to pass air through such mass to form a vapor cloud over said surface, and means to move air over said surface.

This invention is concerned with moisture conditioning of the air. More particularly the invention is concerned with a humidification apparatus having specific application to use in domestic heating units, but capable of utility in other and similar applications as Will be apparent to those skilled in the art.

As is well known, the modern mass-produced residence is generally centrally heated by means of a forced air, gas or .oil fired heating unit. Such units are used extensively for several reasons, ease and economy of installation; utilization of a duct system compatible with central air conditioning installation; and compact design of the heating unit itself, which permits of installation in a limited space. In general the heating unit comprises a combustion chamber for heating a heat transfer .or radiator medium and a blower which forces air over the radiator into a plenum chamber from which the heated air is distributed to outlets in each room of a home, via a sheet metal duct system. The system generally includes one or more return ducts which feed the low pressure side of the blower thus providing for circulation of the air within the particular dwelling.

Systems, as described, are subject to one particular disadvantage in that the moisture content, i.e., relative humidity of the air, is drastically reduced as it passes through the furnace and becomes exceedingly dry. Since human comfolt is closely related to humidity and evaporation of moisture from the body, the dry air tends to create a feeling of coldness or draftiness within a home, even though the temperature of the home may be within a comfortable 68--75 F. range. Also, because dry" air tends to absorb moisture it has been found that damage and warpage of furniture, doors, and some cloth materials does occur as the dry air literally robs moisture from household items and structures. By way of example, it was found that in a home of approximately 1100 square feet, which was heated by a gas fired forced air unit and which was maintained at a temperature of about 72 F. during a period wherein outside temperatures ranged from 10 F.32 F., the relative humidity within the home Was less than 10%. When it is considered that a comfortable range for humidity, depending of course .on temperature, is about 20% at 20 F. and lower, to about 42-45% at 70 F. and above, it is readily seen that forced air systems create a situation which is, at best, uncomfortable and, at worst, contributive of damage to household items and to health problems, palticularly in those persons suffering from certain allergies or upper respiratory Weaknesses which are aggravated by the drying of mucous membranes.

Numerous devices have been devised in attempts to cope with the problem. These include sprays of various types; rotating drums which have a moisture absorbing outer surface exposed to plenum air and passing through a Water bath to continually replenish the surface; or a simple pan into which are placed so-called evaporator plates which are moistened by capillary action and over which the air stream passes. The latter type is by far the most commonly used because its initial purchase price is low and it is relatively simple to install. While the evaporator plate type of humidifier may alleviate the situation of low humidity to some extent, it is subject to several deficiencies and objections which the present invention overcomes.

For example, one of the largest evaporator plate type of humidifiers that is commonly used in domestic dwellings contains 20 evaporator plates. It has been found that with a new set of 20 evaporator plates such a device is capable of introducing into a hot air heating duct approximately four gallons of water per day based upon 24 hours of operation. However, this quantity of moisture is insufiicient to adequately humidify a medium to large size home, particularly during periods of extended furnace operation. Further, it should be recognized that the capacity stated above can only be attained with new evaporator plates and by using the largest evaporator plate type humidifier readily available. More often than not the evaporator plate type of humidifier purchased does not contain more than ten evaporator plates and is therefore wholly inadequate to humidify anything but the smallest home. Even when 20 evaporator plates are used they quickly become fouled by minerals in the Water and their evaporation efiiciency declines sharply. Consequently, the manufacturers of such plates recommend that they be discarded and replaced at least after each heating season or more often, depending again on the severity of service required to adequately heat the particular dwelling. In addition to the inherent deficiencies in the evaporator plates, the pond or pan which supplies water to the evaporating surfaces becomes scummed by dirt and other contaminates and requires periodic cleaning.

The present invention then is directed to the production of a humidifier, primarily for domestic use which has an initial cost comparable to that of an evaporator plate type of humidifier, but which has double the capacity of a 20- plate evaporative humidifier thereby being capable of humidifying the large majority of residential homes. The present invention eliminates the evaporator plates and their inherent deficiencies, and consequently, is relatively maintenance free. Furthermore, its method of operation overcomes the difiiculties of scumming and deposit formations that are prevalent in the evaporator plate type of humidifier.

The present invention, then, is directed to the production of a humidifier, primarily for domestic use, which is extremely efiicient, retaining the features of simple, economical installation characteristic of plate type humidifiers.

An object of the invention therefore, is to provide for a humidifier which may be installed as a new unit or may be incorporated into presently existing humidification devices with but slight modification thereof.

A further object of the invention is to provide a humidificr which is not subject to fouling by contaminates, minerals, etc., in the supply water.

An additional object of the invention is to provide for a humidifier which is more economical to operate than present domestic power operated. humidifiers.

Another object of the invention is to produce an air operated humidifier which operates at extremely low air pressure, on the order of 1-3 p.s.i.g.

Still another object of the invention is to produce a relatively maintenance free humidifier.

A further object of the invention is to provide an air moistening device which requires no periodic replacement of parts, evaporating media and the like.

Still another object of the invention is to produce an air moistening device which rarely requires service or removal from its installation site.

Numerous objects of the invention, aside from the above, but not specifically referred to though inherent therein, may be accomplished by providing an air moistening device comprising a water reservoir, and a means immersed therein including a porous mass characterized by the fact that the pores are open only at their upper ends, means for regulating the water level in said reservoir and means for infusing in said porous mass air under pressure whereby the air emerges from the porous mass and en-trains water from the reservoir carrying same as water smoke into the duct above the level of the reservoir, deflector means disposed above the reservoir for deflecting heated air down upon and over the reservoir surface to continually remove the entrained moisture from said surface and means for moving air to be moistened over the reservoir and past said deflector at a velocity sufficient to continually move the fog from above the surface of the reservoir. Preferably, said deflector is disposed with its lower edge spaced above the porous mass, while the reservoir is provided with an angulated end wall downstream of the deflector.

Having described the invention in broad concept, the details and operation thereof will be understood from the following description considered along with the drawings forming a part of the specification and wherein:

FIG. 1 is a top plan view, partially in section of an apparatus constructed according to the invention, and

FIG. 2 is a side view in section taken along the line 2--2 of FIG. 1.

FIG. 3 is a schematic wiring diagram which illustrates a typical humidity control and operating circuit.

FIG. 4 is a partial sectional view similar to FIG. 2, but showing the invention as a self-contained unit which might be used where there is no air velocity, or in a system where the air flow might be unaccountably low, for example, because of duct size or configuration.

As shown in FIG. 1, and applied to a domestic heating system, the humidifier 10 is installed in a generally horizontal position in the duct, which is a usual and conventional sheet metal duct 1. In the drawings, the heated air from the furnace enters the duct from right to left as illustrated by the arrow. In this case, duct 1 may comprise the main heated air duct leading to the room distribution ducts from the furnace plenum chamber, not shown.

The apparatus comprises in the shape of a trapezium pan 3 having a base side 5 disposed generally transverse to the axis of duct 1, and having two sides parallel to each other, 7, 7' and a fourth side 9 converging to form an apex end 11 disposed downstream in the duct 1. The pan defines a water reservoir being filled via conduit 13 and a float regulated valve 15 actuated by float 17 disposed within pan 3. The float controlled valve, per se, is purely conventional and need not be described in detail. It suflices simply to say that as the water level W in pan 3 drops the float lowers to open valve 15 to restore or maintain the level W constant at a preselected depth.

Water is supplied to conduit 13 from any suitable household source, usually the cold water side of a hot water heater because same is usually conveniently adjacent the furnace, again as purely conventional in usual construction practices.

Immersed within the pan 3 and positioned therein by gravity or any suitable fastening means so as to remain submerged below water level W is a porous block or member 20. This block member is characterized by the fact that its pores 21 are tubular and axially oriented in a parallel relationship, one with respect to the other. By way of example and definition, it has been found that an excellent material for use in the apparatus is a block of wood such as redwood which has a pore structure of the desirable type. Thus, the block 20 may be comprised of a wood having a hollow interior as at 23 the bottom and sides of which have been sealed by dipping same in a coating such as wax whereby the pores 21 are open only at the top surface 25.

Other materials and variations of structure are within the purview of the invention. For example, the block 26 may be formed of a gas impervious material such as metal, defining a chamber having one side formed of an oriented pore material whereby the air can escape only through the porous side. Additionally, the block could be defined by an expanded material such as polystyrene or rubber which is expanded by usual means in one direction to form elongated open ended cells, hollowed out and sealed on all sides except the one upper surface. In any case, the pore structure should be relatively small, yet permit passage of relatively low pressure air and may be defined as on the average equivalent to the pore size of light to medium density wood or the like.

Air is supplied to the interior of the block or porous mass 20 via a conduit 27 from a small low pressure pump, of any suitable type, powered by an electric motor. An excellent pump, having good durability, low power consumption and quiet in operation is that of the type referred to as an aquarium pump commonly used to aerate aquarium water; such pumps being of the vibrator type of extremely low wattage. Also, since the capacity of the pump as to air flow and pressure is very low, use of various other types of miniaturized pumps or compressors are within the purview of the inventive concept as will be apparent as the description proceeds.

Used as a humidification apparatus in a furnace and as illustrated in FIG. 3, the pump motor P may be connected to the same switch T which closes to energize the furnace blower motor B so that the pump operates only when the furnace blower is running. In addition, the power line to the pump motor P passes through a humidity controlled switch H which operates the pump motor P in accordance with the sensed humidity as determined by the humidistat H located so as to be responsive to the air-moisture content in duct 1, upstream of humidifier 10.

Turning to FIG. 2, it will be seen that an "air baffle 30 is disposed above reservoir 3 and has its lower edge spaced downstream from the base wall 5 of the pan 3. The baflie 30 is inclined downwardly having an upper edge disposed above and upstream of the pan 3. In the disclosed arrangement, batfle 30 is carried by a pair of vertical supports 31 and 33 formed with the pan support 35. In a preferred arrangement, baffle 30 is pivoted at 37, 37 and has an adjustable locking connection via slot 39 and screw 41 whereby its angle of inclination may be varied to deflect air over the reservoir surface.

As shown in FIG. 1, the deflector has its lower edge disposed above and upstream of the angulated side 9 of pan 3. While this arrangement produces excellent results, it will be obvious, as the description continues that this relationship may be varied somewhat. The important fact is that the wall 9 of pan 3 is disposed at an angle other than at a right angle to the axis of the duct or, more aptly, to the path of flow of air over the pan 3.

The operation of the device and its application is relatively straightforward. The entire assembly is inserted via an opening into duct 1 which is thereafter closed with a cover plate 45 through which air conduit and water conduit 27 and 13 respectively, are passed for connection to block 20 and valve 15. The air and water conduits are in turn connected to a suitable pump, and the household water system. Float 17 permits pan 3 to be filled to an appropriate level. Assuming low humidity conditions, when switch T closes upon demand for heat, the switch H will be closed so that both the blower motor B and pump motor P are energized.

Air under pressure from the furnace blower moves with considerable velocity down duct 1 and a portion thereof is deflected by baflie 30 down over the surface of reservoir 3. Simultaneously, air from the pump is admitted under low pressure about 1 to 3 p.s.i.g. into the porous mass and, because of the pore characteristics, escapes upwardly, emerging at the surface of the water carrying with it water in the for-m of almost microscopic sized droplets. By suitable regulation of pressure, having in mind pore size, and water level in pan 3, the water is carried up in the form of a vapor fog or smoke clearly visible to the naked eye and closely resembling natural fog. The smoke is carried away from the surface by the downwardly directed flow of heated duct air due to baffle 30.

It has been demonstrated experimentally that the removal of entrained liquid is more efiicient if the downstream side of the reservoir is disposed at an angle which is not perpendicular to the flow of air in the furnace duct. This eliminates a backwash of the surface frothing action that is experienced when the downstream side of pan is disposed perpendicular to the flow of air in the heating duct.

It has also been found that by matching air flow, air pressure, pore size, water level and baffle angle, a vapor smoke can be created and carried into the duct system at a rate which will introduce about eight gallons per 24 hour period and that the smoke or vapor output is so consistently regulated that there is no condensation or spillage of water within the duct. In fact, tests have shown that the stated capacity can be obtained using a small vibrator or positive displacement air pump commonly purchased for aeration of aquariums and with a porous mass having a surface area of only about 15 square inches. Obviously, capacity can be increased by increasing the surface area of the porous mass and the flow or volume capacity of the pump, though in every case operating pressure would remain about 1-3 p.s.i.g.

Several distinct advantages arise from the operation of the invention set forth. First, the complete vaporization obtained obviates duct rust difficulties experienced wherein water is sprayed as distinguished from fogged into the duct air, and condenses on the duct walls or is not completely absorbed by the air. Second, the constant agitation of the reservoir surface has a marked tendency to reduce scum and mineral deposits within the reservoir, a prevalent problem in regular evaporator type devices. Third, the action of the air in the porous mass renders same self cleaning, thus replacement is rarely if ever required. Fourth, the device is both relatively inexpensive to operate and construct, which results in considerable savings both in manufacture for and use by the consumer.

As thus far described, the invention has been related to home humidification in association with a domestic heating system, wherein the heated or duct air velocity is completely adequate to remove the vapor cloud from above the surface of the reservoir. 'In the event that the present invention is to be used in an application Where there is little or no air velocity to remove the entrained liquid, the basic device may be modified as suggested in FIG. 4.

In the modification of FIG. 4, the pan 3, baffle 30, support 35, in fact, all of the components shown in FIG. 1 are present and unchanged. In order, however, to create the essential air flow over the pan, the 'haffle supports 31, 33 are provided with means for moving the air to be treated over the pan 3 as has been described. Various arrangements can be utilized, but for purposes of illustration, not limitation, the supports 31, 33 are interconnected by an apertured fan support wall 49. Fan 53, including motor 55, is mounted on wall 49 by means of two or more strut members 51, 51' and centered in aperture 59. If desired, a top 57 may be provided between supports 31, 33. Obviously, the operation of the device is precisely as described hereinabove, except that the fan serves the function of moving the air over the apparatus.

It should also be noted that the invention can be readily and easily used by converting an existing plate type of humidifier to incorporate the essentials hereof. in such oases, the usual plates are removed, the reservoir and float of existing equipment being unchanged, and the porous block and pump arrangement are substituted in the system. A bafiie is disposed in the duct to deflect air over the surface of the reservoir. In this connection, it should be noted that installation is not confined to merely a horizontal duct since all that is required for vertical duct installation is the elongation of the baffle end into a curving extension into a path parallel to the air flow so that some flow is deflected from the vertical to the horizontal and down over the surface of the reservoir of pan 3 in the manner described herein.

It will be apparent from the description of the invention that various changes and modifications will occur to those skilled in the art which are well within the spirit and scope of the concepts involved, limited only as defined in the appended claims, wherein What is claimed is:

1. An air moisturizing apparatus, a reservoir, means admitting a moisturizing fluid into said reservoir in a preselected amount; a mass having a multiplicity of pores therein disposed in said reservoir, said] mass being characterized by the fact that said pores are open only at their upper ends and are of a pore size equivalent to that of a medium to light density wood, means maintaining a thin layer of fluid over the surface of said mass, batfle means disposed above the reservoir to direct air across the surface thereof; pump means in communication with the interior of the porous mass whereby air pressure within the range of 1 to 3 psi. gauge generated by said pump means is introduced into said mass to produce a smoke-like vapor cloud above the surface thereof, and means for moving air to be treated over the surface so that said vapor cloud is dissipated by the moving air deflected by said baflie means.

2. The apparatus as defined in claim 1 wherein the downstream edge of the reservoir is disposed at an angle so as to be non-perpendicular to the direction of flow of air thereover.

3. The apparatus defined in claim 1 wherein said air moving means comprises a fan integrated with and supported above the surface of said reservoir.

4. The apparatus as defined in claim 1 wherein said baffle is inclined, and the lower edge thereof is disposed above the leading edge of the porous mass and spaced between the downstream and upstream edges of the reservoir, and the upper edge thereof is disposed toward and extends over the upstream edge of the reservoir.

5. The apparatus defined in claim 1 including float means disposed in said reservoir and acting to regulate the level of fluid therein.

6. The apparatus as defined in claim 1 wherein said apparatus is positioned in the output duct of a forced air heating system and said air moving means comprises the furnace blower of said system.

7. The apparatus as defined in claim 6 including means for driving said pump means, said driving means being energized only during heating cycles: of the furnace to which the apparatus is attached,

8. An air moisturizing apparatus comprising a reservoir; means admitting a moisturizing fluid into said reservoir in a preselected amount; a mass having a multiplicity of pores therein disposed within said reservoir, said mass being characterised by the fact that said pores are open only at their upper end; said fluid flowing over the surface of said mass; baffie means disposed above the reservoir to direct air across the surface thereof; pump means in communication with the interior of said porous mass whereby air under pressure generated by said pump means is introduced into said mass to produce a smokelike vapor cloud above the surface thereof; means for moving air to be treated over the surface of said reservoir so that the vapor cloud is dissipated by the moving air deflected by said baffle means, said reservoir being defined by a pan having the shape of a trapezium with the angularly disposed side facing downstream of the edge of the baflie in the direction of movement of the air through said duct.

References Cited UNITED STATES PATENTS 1,208,821 12/1916 Nordell 261124 1,677,502 7/1928 Sweetland 261124 Stark 126-113 X Suppes. Hamann 261-124 X Gross. Skerritt.

Ayres et a1. 126113 HARRY B. THORNTON, Primary Examiner.

1,933,330 10/1933 Johnson 126-413 x 10 TM MILES Exmiw-

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