CA1185427A - Drying device - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A dryer, for drying various materials, having an enclosed housing including an inlet port and an outlet port. Contained within the housing, in between and on opposite sides of the ports, are first and second desiccant columns each containing a desiccant material. An inlet plenum is located between the inlet port and the desiccant columns, and an outlet plenum is located between the restricted outlet port and the desiccant columns, with the inlet and outlet plenums communicating through the desiccant columns. A valve damper is pivotally supported within the housing, located between the desiccant columns, having one end extending across the inlet port to alternately direct air blown into the housing by a blower into one of the desiccant columns. A poppet valve assembly is actuated by the damper to direct dry air into the opposite desiccant column, regenerating that column, before exhausting the air out of the housing. An intermittently operable time controlled solenoid pivots the damper before the desiccant approaches saturation and before the desiccant loses its heat of adsorption.

Description

652.004 DRYING DEVlCE

_ACKGROVND OF THE INVENTION

The present invention relates to dryers for drying various materials9 including hair dryers, dehumidifiers and dehydrators. Conventional apparatus of this type normally include an air blower and a source of heat applied to the moving ambient air and may include a desiccant. Ambient air always includes an existing water load that reduces its ability to absorb additional water and which consumes much of the energy required to raise the ambient air temperature. Often, the use of heated air, particularly in hair dryers, requires the delivery of drying air through a bonnet, which is uncomfortably warm to the user.

The prior art includes the disclosure of a hair dryer having two desiccant units, connected to a blower and a damper means alternately providing communication between one of the desiccant units with Q conduit to a hair dryer hood. A portion of the heated, dry air is alternately directed through the other desiccant unit to regenerate such desiccant unit. During the regeneration process, a heating element is required to heat the desiccant material to facilitate regeneration of the desiccant material, as illustrated for example in United States Patent No. 3,304,6~3.

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1652.004 It has also been conventional to furnish dryers with a desiccant material as illustrated in United States Patent Nos. 2,~73,~13; 2,738,592;
735,507; 2,563,042; and 2,376,095.

Additionally, it is known to provide a dual chambered gas dryer with a bypass valve to regenerate an alumina desiccant material by recycling part of the air through one of the dual chambers, as illustrated in United States Patent No. 3,803,724 The eommercial dryer apparatus of the prior art have several disadvantages, as follows: First, the desiccant material in the desiccant units is generally densely packed, and the units have a long cycle time, i.e. from 30 minutes to several hours before alternating from the drying to regeneration eycle. This necessitates a large amount of desiccant material, increasing the unit cost. Further, the long cycle time causes the desiccant to become less and less efficient, as the desiccant approaches saturation, reducing the drying capability of the unit. The long cycle time also allows the heat of adsorption to dissipate from the desiccant material, wasting energy and necessitating the addition of heat energy to regenerate the desiccant. Finally, the relatively large pressure drop associated with densely packed desiceant units, requires a costly high powered blower operating at high static pressure to move the air through the unit, further increasing the size and cost of the dryer.

The present invention is directed to a dryer which eliminates the large pressure drop associated with conventional dryers, allowing it to operate at a low static pressure, and which conserves the heat of adsorption by the rapid cycling of the system, virtually eliminating the requirement for additional heatenergy to regenerate the desiccant.

S~27 1652.004 SUMMARY OF THE INVENTION

The present invention provides a new approach to drying various materials, such as human hair, clothing or for dehumidifying or dehydrating various enclosures. Specifically, according to the principles OI the present invention, ambient air is alternately and intermittently directed through one of a pair of desiccant columns at low static pressure. The ambient air is rapidly cycled to the second or alternate desiccant column, before the desiccant contained within the first desiccant column reaches staturation and reversed before the desiccant material contained within the second desiccant column loses its heat of adsorpotion. A portion of the dried air is directed through the second desiccant column, regenerating the desiccant material contained therein. A
resistance heater may also be used to warm the dried air before it enters the second desiccant column such that the adsorption time equals l:he regeneration time.

An important feature of the invention is to provide a dryer for material, such as human hair or clothing, which involves passing the air to be treated over a plurality of spaced desiccant baffle assemblies, each containing a water adsorbent desiccant to make the air more hygroscopic, and thereafter continuously passing the dried air over the wet material to be dried ~mtil such air has absorbed the desired amount of water therefrom. The desiccant baffle assemblies, which contain loosely packed desiccant material, create a low pressure drop, providing sufficient air flow at low static pressure. A further feature is to render the ambient air more hygroscopic by removing the existing waterload therefrom and using such air at ambient temperature to dry materi~ls with or without heating.

1652.004 A further feature of the invention is to employ, alternately, ons of the pair of desiccant columns defining passages to remove the moisture in theexisting ambient air in a continuous regenerative system, whereby the heat of adsorption is retained in the columns by rapid cycling. ~y rapid cycling betweenthe columns, the desiccant material in either column is not allowed to reach more than 10% of its saturation load and the retained heat of adsorption is the exact amount of energy required to regellerate the desiccant material contained in the column without additional heat energy.

A further feature of the invention includes application of heat to the dried air before it is passed the material to be dried and over the partia]ly saturated desiccant. In a hair dryer, the dry air would otherwise feel cold to apatron's head so the heater is provided primarily for comfort. The heating of the dry air is also more energy efficient, since no energy is used to heat the original water load which nas already been removed with the passage of the air over the desiccant material. The capacity of the heated dry air for absorbing water has beerl increased. A further reduction of the drying time is achieved if heat is applied to the dried air. The slight warming of the dry air is required to have regeneration time equal adsorption time in a rapid cycling system with no other impetus.

The low pressure requirements of the dryer of the present invention permits the use of a relatively inexpensive low pressure blower. The low pressure drop allows the system to operate at a low static pressure, approximately 0.5 inches of water. Ambient air delivered from an inlet plenum passes through one ô the desiccant columns into an outlet plenum having a restricted outlet for the delivery of dry air therefrom. The restricted outlet produces a back pressure in the outlet plenum, whereby a portion of the total airflow, approximately ten percent, is recycled in the reverse direction, through a second column for passage over the spaced baffle assemblies of the second desiccant column, regenerating the desiccant material within the baffles before exhausting to atmosphere.
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1652.004 A further feature of the present invention includes the use of ~
valve means, such as opposed poppet .ralves, in combination with 6 pivotal damper. The valves are ~ctuated by the pivotal damper, which is adapted for movement between ~ first Qnd second position~ such that the pivotal damper controls the direction of slightly pressurized air from the inlet plenum to one o~
the desiccant columns. In either position, one of the poppet valves is closed and the other is open, so that a portion of the air returning from the outlet plenum, is recycled in the opposite direction, over the other of the two desiccant columns for regenerating the desiccant material therein, before exhausting to ~tmosphere.

There is further employed a damper actuating means, such as a cam timer, for relatively r~pid cycling, ~pproximately one to 1.5 minutes per column. By rapid cycling, the heat of adsorption is retained in the desiccant tofacilitate regeneration of the desiccant material and provide much dryer air since the desicc~nt only approaches ten percent saturation. Thus~ r~pid cyclîng greatly reduces the amo~nt of desiccant required, thereby reducing the cost of the drying device.

These and other objects will be seen from the following specific~tion and claims in conjunction with the appended drawing.
Thus the present invention provides a dryer comprising an enclosed housing including an air inlet and an air outlet; opposed first and second flow desiccant bed ducts on each side of said inlet and outlet;
and an inlet plenum located between said inlet and said opposed flow ducts and an outlet plenum located ~etween said outlet and said opposed flow ducts. The inlet and outlet plenums communicate through ~he flow ducts.
A valve door is pivotally supported within said housing and it has one end extending across the inlet to direct air received from said .~

~8S~7 inlet into one of said flow ducts in a first pivotable position and into said opposite flow duct in a second pivotable position. There is a door actuating means intermittently pivoting said valve door between said first and second positions to alternately and intermittently direct air into one of said first and second flow ducts; and blower means directing air into said inlet.
Each of said flow ducts comprises perforated baffled assemblies of loosely packed desiccant material having a low pressure drop across each baffle assembly. There is a heater means, positioned within the outlet plenum in the air path, adapted for heating the dehydrated air passing through the outlet plenum to render the dry air more hygroscopic for increased drying of the air passing through the outlet and the air returning through the other of the flow ducts for rapid regeneration of the baffle assemblies.
There is a valve means in the inlet plenum which alternately directs air received from one of said flow ducts out of the housing.
The blower means directs air into the inlet. The valve door and the door actuating means alternately and intermittently directs the air into one of the flow ducts, into the outlet plenum, and a large portion of the air out of the outlet, said outlet being a restricted opening and creating a back pressure in the outlet plenum directing a portion of air received from the opposed flow duct into the opposite flow duct;
and said valve means directing said portion of sir received from ~he opposed flow duct out of the housing.

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DESCRIPTION OF THE DRAWING
-Figure 1 is a front perspective view of a hair dryer in accordance with the present invention.

Figure 2 is a fragmentary plan section thereof for the delivery of low static pressurized ambient air alternately thxough a pair of desiccant columns for delivery through a restrictive air outlet port, and for the partial return of a portion of the dried air to the other of the pair of columns, for dehydration and xegeneration of the desiccant material therein~

Fi~ure 3 is a fragment cross-sectional bottom view, of Figure 2.

It will be understood that the drawing illustrates a hair dryer as one preferred embodiment of the invention and that other embodiments and uses are contemplated wi~hin the scope of the claims hereafter set forth.

~185~27 1652.004 DESCRIPTION OF THE PREFERRED EMBODIMENT

The dryer of the present invention, generally designated 10, includes an enclosed dryer housing 12, blower 14, and an air diffusing bonnet 16.
Bonnet 18 is connected to housing 12 by an outlet conduit 18 and connector pipe 20. In the disclosed embodiment~ an air diffusillg bonnet 16 is illustrated, but it should be appreciated that the present invention may be utiliæed for drying various materials such as hair, clothing, or for dehumidifying or dehydrating various enclosures, or in conjunction with air conditioning.

Housing 12 has a front wall 22, rear wall 24, top wall 26, bottom wall 28 and two side walls 30. Front wall 26 includes an inlet port 32 and rear wall 24 includes a restricted outlet port 34. Housing 12 contains opposed first and second desiccant columns 36 and 38 on each side of inlet port 32 and outlet port 34.

A pair of longitudinally spaced partitions 40, 42 are spaced inwardly of rear wall 24 and front wall 22, respectively, extending between the top and bottom walls 26, 28, defining within housing 12 air inlet plenum 44 communicating with inlet 32, and outlet plenum 46 in communication with restricted outlet port 34, see ~igure 2.

A plurality of spaced desiccant baffle assemblies 50 are c-~ntained within first and second desiccant columns 36, 38. As illustrated, the baffle assemblies 50 are removeably mounted within the desiccant columns 36, 38 in grooves S2. Grooves 52 are formed in partitions 40 and 42 in conj~mction with vents 48. Inlet plenum 44 and outlet plenum 46 communicate through first and second desicc~ant column 36, 38 by way of vents 48, see Figures 2 and 3.

~S~7 1652.004 Baffle assemblies 50, in the disclosed ernbodiment, are constructed of wire screening 54, for example 1/8 inch mesh aluminum wire containing loosely paclced desiccant. A suitable desiccant is activated aluminumoxide9 referred to as alumina, in the forms of beads or pellets having a size which would not pass through a screen mesh of Q.25 inches.

While other desiccants may be employed, such as granular silica gel) it is contemplated that the preferred desiccant is a porous aluminum oxide of a particulate form and preferrably in the form of beads to facilitate the passage of ambient air over and through the baffle assemblies 50.

A valve damper 56 is pivotally mounted to partition 40 between first and second desiccant columns 36, 33, within ehamber 57, by pivot hinge 58.~amper 56 has one end extending across the inlet port 32, directing ambient air received from inlet port 32 into one of the desiccant columns 36, 38 in a first pivotal position and into the other column in a second pivotal position. Stops 60, attached to front wall 22 on each side of inlet port 32, limit the degree of pivoting of damper 56. An intermittently operable power means, such as a solenoid 90, pivots darnper 56 between its first and second positions to alternately and intermittenly direct air into desiccant columns 36 and 38.
Solenoid 90 is connected to damper 56 by two lever arms 96 and 980 In the disclosed embodiment, the solenoid 90 is a Dormeyer pull type solenoid, 115 volts AC, 60 HZ, 0.6D amps. The solenoid is connected into an electrical power circuit, which includes repeat cycle timer 92 and a power source 94. The timer in this embodiment is a Dayton Cycle Timer Model 2E130, whieh may be set in the illustrative embodiment for 1.5 minute time cycles. As ~n alternative, a continuous 1 or 1.5 RPM electric motor, such as a Dayton, Model LR 31462-3048 may be used in combination with a Geneva gear assembly, which causes the damper to cycle at 1 or 1.5 minute intervals. The particular time cycle will depend on several factors including the amount cf air flow.

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1652.G04 ~ valve means, such as a pair of opposed poppet or butterfly valve assemblies are located in inlet plenum 4~ fo~ alternately directing air receivedfrom one of the desiccant columns 36, 38 out of housing 12. In the disclosed embodiment a pair of opposed poppet valve assemblies are illustrated. A first poppet valve 66, including a rod 68, is located on one side of inlet plenum 4~L to direct the air received from first dessicant column 36 through exhaust opening 70 and out of housing 12. Opening 70 is formed in housing side 30. Poppet valve 66 is supported within inlet plenum 44 by support bracket 72. A spring 74 biases valve 66 against opening 70 in a normally closed position. ~ second poppet valve ~6, including a control rod 783 is located on the opposite side o~ inlet plenum 44 to direct the air received from second desiccant column 38 through exhaust openin~ 80 out of housing 12. Opening 80 is formed in side 30. Second poppet valve 76 is supported within inlet plenum 44 by support 82. A spring 84 biases valve 76 against opening 80 in a normally closed position.

As schematically shown in ~igure 2 an air blower 14 is connected to inlet port 32 and inlet plenum 44. A suitable air Mower is sold by Fasco Industries, Inc.3 Model 002101X05, operating at 150 volts A~, ~0 H7, 1.45 amps.
The air blower is adapted to deliver ambient air at approximately 120 cubic feetper minute and create a static pressure of approximately û.5 inches of water.

An electric resistance heater 88, such as a cal rod heater or nichrome wire, extends into outlet plenum 46 in the path of movement of dry air therethrough and is adapted to heat the dry air passing into outlet plenum 46.
The air then passes through restricted outlet port 34 and outlet conduit 18, connected to housing 12 and at one end m~unting the dry air diffusing bonnet 16.Mllltiple heater elements may be employed as schematicaUy shown at 88 delivering 2bo watts to 14û0 when watts energized singularly or combined. For illustration, a suitable hleater element is sold by Hartford ~:lement Co., Model10350. The electric resistance heater 88 is interposed in a circuit which includes normally open switch 100 connected to a suitable power source 102.

~5~a~7 1652.004 The principal purpose o the heater 88 in the disclosed hair dryer of this invention is to warm the air exiting outlet port 3~, increasing the comfort of the user. It will be wlderstood however that the heater also reduces the regeneration time requirements of the desiccant, making the dryer more eff icient. It has also been found that the elimination of the hea~er in the disclosed embodiment will eventually result in a loss of regeneration capacity.
The preferred embodiment therefore includes a low capacity heater in the outlet plenum 46. The prior art however requires heating of the saturated desiccant material, which requires substantially more energy.

For some operations of the present hair dryer, control switch 100 to electrical power source 102 for the heater 88 is left off. Dry air without heating moves through the restri~ted outlet port 34 to bonnet 16. As desired andon activation of the switch 100, electrical power is provided to the heater 88 for heating the dried air to the extent needed.

~chematically shown in Figure 1 is one means by which the present dryer may be used within a room area such as in a beauty parlor or in the home. When the present air dryer is utilized as a dehumidifier or for providing dried air to the inlet of an air conditioner, or for drying clothes, the respectiYe exhaust openings 70 and 80 are extended through a building or room wall. Thus, the dried air picks up water during regeneration of the desiccant and is exhausted to the outside of the room or building wall maintaining low humidity therein.

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l652.004 OPERATION

As illustrated in Figure 2, blower 14 blows ambient air at relatively low static pressure through inlet port 32 ;nto inlet plenum 44.
Damper 56, in a first position, directs ambient air into second desiccant column 38 and over desiccant baffle assemblies Sû, contained therein9 making the ambient air more hygroscopic by removing the existing water load by adsorption.
Exhaust opening 80 is closed forcing aU the air flow through second desiccant column 38. Dry air flows out of second desiccant column 38 into outlet plenum 46 and passes over the electric heater 88 which may be energi2ed.

The restricting outlet port 34 creates a differential pressure or back pressure within plenum 46, which causes a portion of the dry air therein to flow through the first desiccant column 36 in the opposite direction to the flow through second desiccant. column 38. The small flow of dry air is sufficient to remove any water whic h was collected by the desiccant material in b~ffle assemblies 50 contained therein from the previous passage of air therethrough, thereby regenerating it and continuously flowing through the exhaust opening 70 to atmosphere.

After a specific period of time, such as for example 1 or 1.5 minutes in a particular application, damper 56 is alternated to its second position as shown in phantom in Figure 2. Damper 56 and poppet valves 66, 67 are positioned to cause air flow through first desiccant column 36 while blocking ambient air flow through second desiccant column 3S.

Exhaust opening 70 is then closed, forcing all the ambient air flow through first desiccant column 36, and exhaust opening 80 is opened to atmosphere, allowing regenerativ-e air to flow through second desiccant column 38 and out of housing 12 through exhaust opening 80.

1652.004 In ~he case of commercial hair dryers, less energy will be consumed for facilitating air conditioning because less heat will be released into the facilities ambient air. The process of obtaining hygroscopic air to dry other materials, such as clothing, is the same with respect to components for the application of dry air directed over a wet material other than hair. The presentembodiment may also be employed for dehumidfying enclosures such as rooms or buildings which involve the use of refrigeration for air conditioning. Thereforethe above described air dryer may be employed to regulate the relative humidity of enclosures that are subject to a higher relative humidity than desireable.

The present dryer may be ernployed for any drying system, other than hair drying, as for example, the drying of clothes or for dehumidifying a roorn area. The present dryer reduces energy consumption by utilizing the heat of adsorption retained on the desiccant material to facilitate regeneration. In addition, heat is applied to air already dried passing through the desiccant columns 36 or 38 alternately after the water load has been removed from the air so that regeneration time equals adsorption time.

The cycle of operation of the present hair dryer or other air dryer is automatic and continuous for the delivery of dry air to the outlet plenum 46 and the recirculation of some of the dry air for regeneration and dehydrating the desiccant material within the respective perforated baffle assemblies 50.

The use of the present dual columned system alternately utilizing the desiccant contained within a pair of desiccant columns 36, 33 for drying theair and for alternately drying the desiccant material is a continuous process.

1652.004 This invention may be further developed in the scope of the following claims. Accordingly~ the above specification is to be interpreted as illustrative of only a single operative embodiment of this invelltiorl~ rather than in a strictly limited sense.

I now claim.

Claims (12)

1. A dryer comprising:
an enclosed housing including an air inlet and an air outlet;
opposed first and second flow desiccant bed ducts on each side of said inlet and outlet;
an inlet plenum located between said inlet and said opposed flow ducts and an outlet plenum located between said outlet and said opposed flow ducts;
said inlet and outlet plenums communicating through said flow ducts;
a valve door pivotally supported within said housing having one end extending across said inlet to direct air received from said inlet into one of said flow ducts in a first pivotable position and into said opposite flow duct in a second pivotable position;
door actuating means intermittently pivoting said valve door between said first and second positions to alternately and intermittently direct air into one of said first and second flow ducts;
blower means directing air into said inlet;
said flow ducts each comprising perforated baffle assemblies of loosely packed desiccant material having a low pressure drop across each baffle assembly;
a heater means, positioned within said outlet plenum in the air path therein, adapted for heating the dehydrated air passing through said outlet plenum rendering said dry air more hygroscopic for increased drying of the air passing through said outlet and the air returning through the other of said flow ducts for rapid re-generation of said baffle assemblies;
valve means in said inlet plenum;
said valve means alternately directing air received from one of said flow ducts out of said housing;
said blower means directing air into said inlet;
said valve door and door actuating means alternately and intermittently directing said air into one of said flow ducts, into said outlet plenum, and a large portion of said air out of said outlet;

said outlet being a restricted opening and creating a back pressure in said outlet plenum directing a portion of air received from said opposed flow duct into the opposite flow duct; and said valve means directing said portion of air received from said opposed flow duct out of said housing.

2. The dryer defined in claim 1, wherein said heater means includes an electric resistance heater coil selectively adjustable for producing heat in the range of 200 to 700 watts, approximately.

3. The dryer defined in claim 1, wherein said heater means provides drying air through said air outlet in a temperature in the range 80° to 90°F., approximately.

4. In the dryer defined in claim 1, wherein said baffle assemblies contain a desiccant material being alumina.

5. The dryer defined in claim 1, further comprising an air diffusing bonnet connected to said dry air outlet for directing dry air onto a persons wet hair.

6. The dryer defined in claim 5, wherein the connection of said bonnet to said air outlet includes an outlet sleeve at one end connected to said outlet plenum in communication with said dry air outlet, and at its other end connected to and supporting said bonnet for delivering dehydrated air therethrough.

7. The dryer defined in claim 1, wherein each of said baffle assemblies includes a hollow enclosure of wire mesh screening, a desiccant material being of particular form and loosely netted in each of said baffle assemblies.

8. A method of drying air for use in drying materials, comprising the following steps:
(a) blowing ambient air at low static pressure through a dryer inlet port into a dryer housing;
(b) means directing said ambient air into one of a pair of opposed desiccant columns, contained within said dryer housing;

(c) intermittently directing said ambient air into the other of said desiccant columns before said desiccant column approaches saturation and before said other desiccant column loses the heat of adsorption contained therein;
(d) passing said ambient air over a plurality of spaced baffles containing a desiccant, within said columns, drying said ambient air;
(e) creating a back pressure in an outlet plenum of said housing by directing said dry air into said outlet plenum and out through a restricted outlet port;
(f) directing a portion of said dry air received in said outlet plenum into said other desiccant column;
(g) directing said portion of said dry air over said spaced desiccant baffles, within said other desiccant column, regenerating the desiccant in said baffles; and (h) directing the air received from said opposed desic-cant column out of said housing.

9. The method of drying air defined in claim 8, wherein the pressure drop associated with blowing air through said desiccant is a relatively small percentage of the static operating pressure.

10. The method of drying air defined in claim 9, wherein said ambient air is alternately and intermittently rapid cycled into one of said desiccant columns in intervals of not greater than two minutes per column.

11. The method of drying air defined in claim 8, wherein said ambient air is blown through said inlet port into said housing at relatively low static pressure.

12. The method of drying air defined in claim 8, wherein said dry air in said outlet plenum is heated by an electric heating means providing the impetus whereby regeneration time is not greater than adsorption time.