U.S. patent application number 10/464243 was filed with the patent office on 2004-12-23 for spin cycle methodology and article drying apparatus.
Invention is credited to Hallman, Darren, Mani, Vanita, Sundell, Robert.
Application Number | 20040255394 10/464243 |
Document ID | / |
Family ID | 33517251 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040255394 |
Kind Code |
A1 |
Mani, Vanita ; et
al. |
December 23, 2004 |
Spin cycle methodology and article drying apparatus
Abstract
A method for drying articles is provided comprising, providing a
wash basket within a wash drum inside a washing machine and an air
stream which follows an air flow path through the wash basket and
through the machine. Then engaging a heater located along the air
flow path, engaging a cooling unit located along the air flow path,
and spinning the wash basket with the heating unit and cooling
units engaged. Also provided is an apparatus for drying articles
comprising, an air stream which follows an air flow path through a
washing machine comprising a wash basket, a heating unit located
along the air stream, a cooling unit located along the air stream,
and a supplemental heater located along the air stream.
Inventors: |
Mani, Vanita; (Clifton Park,
NY) ; Hallman, Darren; (Clifton Park, NY) ;
Sundell, Robert; (Clifton Park, NY) |
Correspondence
Address: |
Todd W. Galinski
Kilpatrick Stockton LLP
1001 West Fourth Street
Winston-Salem
NC
27101
US
|
Family ID: |
33517251 |
Appl. No.: |
10/464243 |
Filed: |
June 18, 2003 |
Current U.S.
Class: |
8/159 ; 34/321;
34/443; 34/598; 68/18C; 68/19.2; 68/20; 8/149.2 |
Current CPC
Class: |
D06F 2105/28 20200201;
D06F 2103/36 20200201; D06F 2103/50 20200201; D06F 35/007 20130101;
D06F 58/206 20130101; D06F 2105/26 20200201; D06F 58/30 20200201;
D06F 2105/24 20200201; D06F 43/02 20130101 |
Class at
Publication: |
008/159 ;
008/149.2; 068/018.00C; 068/019.2; 068/020; 034/321; 034/443;
034/598 |
International
Class: |
D06F 029/00 |
Claims
What is claimed is:
1. A method for drying articles comprising; providing a wash basket
within a wash drum inside a washing machine; providing an air
stream which follows an air flow path through the wash basket and
through the machine; engaging a heating unit located along the air
flow path; engaging a cooling unit located along the air flow path;
and spinning the wash basket with the heating unit and cooling unit
engaged.
2. The method of claim 1, wherein the heating unit and cooling unit
comprise a vapor compression system and are in fluid communication
through a compressible working fluid.
3. The method of claim 1, further comprising allowing any excess
wash fluid that is spun off the articles to drain out of the wash
drum.
4. The method of claim 1, wherein the wash basket is spun to
achieve a centrifugal force of 150 g to 300 g.
5. The method of claim 1, further comprising providing a blower
located along the air flow path and engaging the blower before
spinning the wash drum.
6. The method of claim 1, further comprising a supplemental heater
located along the air flow path and engaging the supplemental
heater before spinning the wash drum.
7. The method of claim 1, wherein the cooling unit comprises a
compressor fluidly connected to cooling coils wherein the
compressor compresses a working fluid that passes through the
cooling coils and absorbs heat from the air passing the coils.
8. The method of claim 1, further comprising; providing a blower
along the air flow path; engaging the blower to circulate air
through the washing machine along the air flow path; tumbling the
wash drum with the heating unit, cooling unit, and blower engaged
wherein air passes through the cooling unit reducing the moisture
content, passes through the heating unit where the air is heated,
and passes through the wash basket where the sir absorbs wash fluid
from the articles thereby reducing the moisture content of the
articles.
9. The method of claim 8, wherein wash fluid absorbed by the air
stream from the articles is condensed within the cooling unit to
provide an air stream with reduced moisture and a wash fluid stream
which can be recycled or disposed.
10. The method of claim 8, further comprising a supplemental heater
located along the air flow path wherein the supplemental heater
provides additional heat to the air stream before it enters the
wash basket.
11. The method of claim 10, wherein heat is provided to the
supplemental heater by transferring the heat given off by the
compressor to the supplemental heater.
12. The method of claim 10, wherein heat is provided to the
supplemental heater through a resistive element associated with the
supplemental heater.
13. The method of claim 8, wherein wash fluid laden air exits the
washing machine after leaving the wash basket and fresh ambient air
entering the machine is conditioned by the heating and cooling
units and enters the wash basket.
14. The method of claim 8, wherein the air is recirculated
throughout the machine in a closed loop system.
15. An apparatus for drying articles comprising; an air stream
which follows an air flow path through a washing machine
comprising: a wash basket; a heating unit located along the air
stream; a cooling unit located along the air stream; and, a
supplemental heater located along the air stream.
16. The apparatus of claim 15, wherein the heating unit and cooling
unit comprise a vapor compression system and are in fluid
communication through a compressible working fluid.
17. The apparatus of claim 15, further comprising a blower.
18. The apparatus of claim 15, wherein the cooling unit and the
supplemental heater have a thermal transfer medium there between.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to methods and apparatus for
drying articles using a combination of heating and cooling elements
incorporated into the spin cycle of a washing machine.
BACKGROUND OF THE INVENTION
[0002] Current household clothes washers use water as the cleaning
fluid. Normal horizontal and vertical axis washers use anywhere
between about 60 liters (16 gallons) and about 189 liters (50
gallons) to wash a typical load of clothes. A large amount of
energy is expended in the conventional wash process due to the use
of hot water to improve wash effectiveness and the hot air drying
process during which the retained water is evaporated. The high
energy requirements of conventional home laundry systems increase
the operational cost for the consumer and puts a strain on the
environment, depleting natural resources and contaminating
water.
[0003] Recently, use of a cyclic siloxane composition for washing
purposes was disclosed in U.S. Pat. No. 4,685,930 and No.
6,063,135, which is intended to replace conventional
perchloroethylene (PERC) professional dry cleaning solvent, which
has been shown to be hazardous to human health as well as a danger
to the environment. Additionally, the use of a siloxane solvent in
laundering has shown to result in reduced wrinkling, superior
garment care and better finish than water washing. Current
technology provides dry cleaning machines that use the cyclic
siloxane dry cleaning process in both home and commercial settings.
Further improvements on washing using a cyclic siloxane and
siloxane/water mixture have also been suggested. The present
invention augments this implementation with a specific methodology
that optimizes the spin and dry cycle.
[0004] Centrifuging or spin extraction of the solvent at the end of
the wash process is not a new idea. This is a common and effective
method of extracting the solvent prior to commencement of the
drying cycle. By removing wash solution through centrifugation,
less heated drying time is required which is energy expensive.
Thus, removing wash solution through centrifugation has a much
lower energy cost than heated drying, however there is a limit to
the amount of wash solution that can practically be removed during
spin extraction.
[0005] Most dry-cleaning and water-wash processes involve a spin
extraction cycle. Literature on the commercial implementation of a
siloxane-based system includes a spin cycle, generally at about
350-750 rpm. Often this spin cycle is accompanied by heated air or
a vacuum stage to enhance the evaporation of the wash solution.
These aspects of spin/dry cycles are discussed in U.S. Pat. Nos.
6,063,153 and 6,086,635.
[0006] While these spin and dry cycles do produce a dried article,
they do not have the combined advantages of energy savings and
minimized dry time that overcome the disadvantages of high energy
and operational cost associated with prior art spin and dry cycles.
These cycles are merely a carryover from traditional spin and dry
cycles used in common water based washing machines. There have been
no significant improvements to these cycles in recent years.
[0007] Thus, there is a need for an integrated wash and dry system
design in a siloxane-based home laundry machine that minimizes the
overall cycle time and energy usage. It would be desirable to
implement a spin and dry cycle while simultaneously conditioning
the system using a cooling unit, heating unit and optionally a
supplemental heater to lower the solvent retention in the washed
articles. Furthermore, specifically optimizing the system to
minimize total cycle time and energy usage through the use of the
components in a particular sequence has not been addressed in the
prior art. It is to these perceived needs that the present
invention is directed.
SUMMARY OF THE INVENTION
[0008] The present invention provides a drying methods utilizing a
combination of features during the spin cycle of this laundry
machine to minimize cycle time and energy usage. Specifically, this
involves including a heating system, which heats the drum during
the spin cycle resulting in lower retention at the end of the spin
cycle, and conditioning of the air through a condenser. Design
implementation involves several features that are specifically
designed for consumer use in an in-home or coin-op laundry setting.
These features ensure the entire unit fits within the space
envelope of a conventional home laundry system, low cycle time and
energy usage and ability to operate the machine on normal house
power outlets, i.e. from 100 to 250V.
[0009] In an embodiment of the present invention, a method for
drying articles is provided comprising, providing a wash basket
within a wash drum inside a washing machine and an air stream which
follows an air flow path through the wash basket and through the
machine. Then engaging a heating unit located along the air flow
path, engaging a cooling unit located along the air flow path, and
spinning the wash basket with the heating unit and cooling units
engaged.
[0010] In another aspect of the present invention, an apparatus for
drying articles is provided comprising, an air stream which follows
an air flow path through a washing machine comprising a wash
basket, a heating unit located along the air stream, a cooling unit
located along the air stream, and a supplemental heater located
along the air stream.
[0011] The present invention includes an apparatus and method used
in conjunction for the spin extraction and drying cycles during
cleaning of fabrics, textiles and the like at home or in a coin-op
laundry setting. The methods and apparatus of the present invention
are particularly well suited for solvent based cleaning.
[0012] Features of a method for drying articles of the present
invention may be accomplished singularly, or in combination, in one
or more of the embodiments of the present invention. As will be
appreciated by those of ordinary skill in the art, the present
invention has wide utility in a number of applications as
illustrated by the variety of features and advantages discussed
below.
[0013] As will be realized by those of skill in the art, many
different embodiments of a method for drying articles according to
the present invention are possible. Additional uses, objects,
advantages, and novel features of the invention are set forth in
the detailed description that follows and will become more apparent
to those skilled in the art upon examination of the following or by
practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagram of a washing machine including an
embodiment of the present invention.
[0015] FIG. 2 is a diagram of an embodiment of the system of the
present invention.
[0016] FIG. 3 is a diagram of the vapor compression system of an
embodiment of the present invention.
[0017] FIG. 4 is a diagram of an embodiment of the present
invention wherein the supplemental heater receives heat from the
compressor.
[0018] FIG. 5 is a chart showing wash fluid retention as a function
of spin acceleration.
[0019] FIG. 6 is a chart showing wash fluid retention as a function
of spin time.
DETAILED DESCRIPTION
[0020] In a first aspect of the present invention, an apparatus for
drying articles is provided in which the articles are dried after a
cleaning process wherein the drying is achieved in less time and at
a lower energy cost than has been previously achieved. The
components of the drying apparatus may be employed in a home based
or coin op laundry machine, or scaled up in a commercial laundry.
This application describes an embodiment comprising the home based
washing machine, specifically a washing machine designed for home
use that uses a cyclic siloxane wash fluid, a water based wash, or
a combination of the two. However, it is well within the scope of
this invention that the methods and apparatus disclosed herein may
be employed in washing machines of any size.
[0021] Referring to FIG. 1, the apparatus of the present invention
comprises a washing machine 10 designed to use a siloxane based dry
cleaning fluid, water, or a combination of siloxane based cleaning
fluid and water. It is recognized that the present invention may be
employed with other solvent-based cleaning systems to decrease dry
cycle time and energy costs.
[0022] The term "articles" as used herein describes generally
fabrics, textiles, garments, linens, and any other material
commonly cleaned in a home water based washing machine, or
commercial dry cleaning apparatus.
[0023] In one embodiment of the present invention, the apparatus
for drying is incorporated into a washing machine 10 generally
comprising a wash basket 20 enclosed in a wash drum 22. The wash
basket 20 is perforated or otherwise has apertures therein to allow
liquid and vapor to pass through while retaining the articles. The
wash drum has a wash fluid entrance port or ports 54 through which
wash fluid is pumped from a reservoir 50 by a pump 40. In other
embodiments of the present invention, the wash fluid is allowed to
drain via gravity into the wash drum 22. The wash basket 20 is
rotated by means of a motor 30 and drive system. The motor and
drive system are capable of spinning the basket 20 at various
speeds, for example at high speed for a spin cycle and a lower
speed for a tumble/dry cycle.
[0024] The washing machine 10 also comprises a wash fluid exit port
or ports 60 in the wash drum 22 which allow the wash fluid to drain
away from the articles upon completion of a wash cycle.
Additionally, there is a wash fluid drainage line 12 from the
chiller to collect and transport condensed wash fluid vapor. The
wash fluid is drained into a working tank 54 for storage or
disposal. In one embodiment of the present invention, the wash
fluid is fed into a cleaning or regeneration system 13 to clean the
wash fluid, separate any water from the siloxane based fluids and
return the cleaned wash solution to the fluid reservoir 50.
[0025] The apparatus of the present invention is incorporated into
the aforementioned washing machine, or a similar machine through
the addition of a blower 80, heating unit 90, and chiller/vapor
compressor 11 as seen in FIG. 1. FIG. 2 shows the article drying
apparatus 100 of an embodiment of the present invention. Air
entering the wash drum 10 is heated by a heating unit 120 to
increase the temperature of the air entering the wash drum 10 and
thereby increase the rate of evaporation of wash fluid from the
articles into the air stream.
[0026] Additionally the entering air is conditioned to provide
maximum wash fluid evaporation and absorption before leaving the
drum 110. The air is conditioned through a cooling unit comprising
a chiller 130 that condenses vapor in the air and provides a drier
air stream capable of absorbing more wash fluid. This vapor
compression cycle comprises cooling coils 130 that have a
refrigerant, for example fluorocarbon R-22, as a working fluid. The
refrigerant is condensed using a compressor as is known in the art
and allowed to expand in the cooling coils while absorbing energy.
As the air stream passes the cooling coils 130, any vapor, be it
siloxane vapor or other cleaning fluid, will condense leaving the
air stream drier and able to pick up more cleaning fluid as it
passes through the wash basket.
[0027] The amount of condensate will depend on a number of factors
including the relative saturation of the air, the rate at which
heat is extracted through the cooling coils and the surface area of
the cooling coils, as well as other factors known to those skilled
in the art. The properties of the cleaning fluid, such as vapor
pressure, will also affect the rate of condensation. Thus, the size
of the cooling coils and compressor will vary depending on the
needs of the particular application, and will be apparent to one
skilled in the art.
[0028] In another embodiment of the present invention, the heating
unit and cooling unit together comprise a vapor compression system.
Such a system is commonly known as a heat pump or vapor compression
system and is shown in FIG. 3. The vapor compression system
comprises the heating unit 120, the chiller 130 a compressor 135, a
pressure reducing device 125, and a working fluid, such as a
refrigerant like fluorocarbon R-22. The compressor 135 compresses
the working fluid causing it to become a hot high pressure gas.
This hot compressed gas runs through the heating coils in the
heating unit 120 where some of the heat is transferred to the air
stream cooling the working fluid and turning it into a liquid. The
liquid working fluid runs through an expansion valve 125 where it
is allowed to expand and become a cold low pressure gas. This cold
low pressure gas then passes through the cooling coils where the
gas absorbs heat from the air stream. This cools the air stream and
causes moisture in the air stream to condense on the exterior of
the cooling coils. At the same time the working fluid absorbs this
heat and returns to the compressor 135.
[0029] In a further embodiment of the present invention a
supplemental heater 140 is provided to assist the heating unit 120
in heating the air stream prior to entering the wash drum 110. In
one embodiment of the present invention, the supplemental heater
140 comprises a resistive element 142, which is used to heat water
that carries heat to a heat exchanger in the supplemental heater to
transfer the heat to the air stream. Instead of water, other
acceptable heat transfer mediums include, but are not limited to,
glycol, water-glycol mixtures, synthetic oil, mineral oil, air, or
silicones.
[0030] In another embodiment of the present invention, the
supplemental heater 140 operates to employ the heat given off by
the compressor associated with the chiller 130 to further heat the
air stream. As the compressor compresses the working fluid in the
chiller 130, heat is produced. This heat is then captured by a heat
transfer medium and carried to the supplemental heater. In one
embodiment of the present invention, water is circulated through
the compressor to extract heat and carry it to the supplemental
heater where the heat is transferred to the air stream. This
provides additional heat to the sir stream with minimal additional
energy cost to the system.
[0031] The supplemental heater allows more precise control of the
air stream than is possible using only the heating unit described
above. It also provides the option of providing significant
additional heat, which would be required for drying in a water
based wash cycle which would require higher temperatures for
drying. In another embodiment of the present invention, the
supplemental heater is capable of controlling the temperature of
the air stream between 100.degree. F. and 170.degree. F. and
provides between 0 and 6000 Watts of power.
[0032] In one embodiment of the present invention, the components
of the apparatus are combined in no particular order. However, in
another embodiment, the chiller 130 is located along the air stream
immediately after the drum 110 so that any vapor in the air stream
can be removed and recycled or disposed. The air stream then passes
the heating unit 120 and, optionally, the supplemental heater 140
before entering the drum 110. A blower 150 is positioned at one or
more points along the air route to move the air stream along.
Preferably the blower 150 is located after the chiller 130 such
that the air entering the blower is substantially free from vapor
which can harm the blower components. The blower may be any air
movement means known in the art such as a fan.
[0033] In yet another embodiment of the present invention, shown in
FIG. 4, the components of the article drying apparatus 200 are
arranged in a manner to minimize the energy used by the machine.
After leaving the drum 210 air, laden with wash fluid vapor 212,
passes through the cooling coils 230. The cooling coils 230 are
fluidly connected to a compressor 232 which compresses the working
fluid and transfers it 234 to the cooling coils 230. The compressed
working fluid is allowed to expand in the cooling coils 230 during
which it absorbs heat and cools the coils. As the air leaving the
drum 212 passes the cool coils 230, wash fluid vapor will condense
and is returned to a wash fluid storage tank though a return line
216. The result is an airflow 238 that contains less wash fluid
vapor than the airflow leaving the drum 212. Once the working fluid
has absorbed heat through the cooling coils 230 it makes the return
trip 236 to the compressor 232 to be recompressed.
[0034] The air leaving the cooling coils 238 is moved through the
system via a blower 250 or other air mover to a heating unit 220
where the temperature of the airflow is increased. Air leaving the
heating unit continues to the supplemental heater 240 where it is
further heated to the desired temperature before reentering the
drum 210. The supplemental heater 240 is in fluid connection with
the compressor 232 such that water circulating between the
supplemental heater 240 and the compressor 232 carries heat
discharged by compression 244 to the supplemental heater 240 and
then returns 246 to the compressor to retrieve more heat. The air
stream leaving the supplemental heater 248 is hot and relatively
free of moisture so as to effectively remove more wash fluid from
the articles in the wash drum 210.
[0035] The above described apparatus is employed according to the
following methods in order to minimize drying time and energy usage
during a cleaning cycle. The following methods are illustrative of
some embodiments of the present invention and modifications and
variations will be apparent to those skilled in the art.
[0036] A second aspect of the present invention comprises a spin
and dry cycle for a washing machine which minimizes total drying
time and energy usage. In one embodiment of the present invention,
the method of drying begins with the completion of a wash cycle.
Referring to FIG. 1 as an exemplary apparatus for performing the
methods of the present invention, the wash cycle generally
comprises placing the articles in a horizontally rotating wash
basket 20 of the solvent cleaning system 10. The cleaning basket 20
is rotated by means of an electrical motor 30. The wash cycle is
then initiated after a cleaning fluid 50 is pumped into the wash
basket 20 by pump 40. The cleaning fluid constituents are presented
for illustration and without limitation as cyclic siloxane, water,
detergents, sanitizing agents and other related materials desired
for effective washing.
[0037] The basket 20 containing the articles and cleaning fluid is
agitated for a predetermined period of time to ensure proper
contact and mixing between the cleaning fluid and the articles.
Once the articles and cleaning fluid are sufficiently agitated, a
check valve 60 is opened, and the cleaning fluid is drained into a
working tank 54. The wash basket 20 is then centrifuged by the
electric motor 30 to extract the residual cleaning fluid left in
the articles. As the basket 20 is spun, any remaining cleaning
fluid is thrown to the outsides of the wash basket 20 and allowed
to drain in to the working tank 54. It is at this point in the wash
cycle that the method of the present invention is employed.
[0038] In one embodiment of the present invention, a method of
drying articles is provided comprising engaging at least one of a
heating, cooling or supplemental heating element during the spin
cycle. This includes the heating coils, the condenser and cooling
coils, the supplemental heater and the blower. In another
embodiment of the present invention, the heating coils, condenser
coils and supplemental heater are turned on during the spin cycle
while the blower remains off. After the spin cycle is completed, a
dry cycle begins and the blower is engaged to assist air flow
through the other components and to the wash basket.
[0039] The spin and dry cycles in an embodiment of the present
invention are similar to those generally known to one skilled in
the art of laundering. A spin cycle removes excess wash fluid
primarily through centrifugal extraction by spinning the basket at
a high rate of speed. A typical spin cycle comprises a basket spin
rate of about 500 to about 1200 rpm and will produce a force of
150-300 g on the articles in the basket, depending on the size of
the basket. This force pulls the water through and away from the
articles and outside the wash basket. In contrast, a dry cycle
rotates the basket much more slowly to tumble the articles while
forcing air past the articles to absorb wash fluid from the
articles to the air. In a dry cycle, the wash basket typically
rotates no faster than 100 rpm to ensure efficient contact between
the passing air and the articles to produce uniform drying.
[0040] Depending on the size of the drum, the rpm needed to achieve
a certain g force would be different. The equation relating the
drum diameter, rpm and g force is given by: 1 G = ( D 2 ) ( 2 60 N
) 2 9.81
[0041] where G is the centrifugal force applied, expressed as a
factor over acceleration due to gravity, D is the drum diameter in
meters, N is the drum rotation speed in revolutions per minute
(RPM) and 9.81 is the acceleration due to gravity in m/s.sup.2. For
example, a drum diameter of 0.54 m and speed of 1000 RPM results in
300 g force. A larger drum diameter would need a higher speed to
achieve this G force.
[0042] Even though the blower is off during the spin cycle, some
airflow results due to the high centrifugal force imposed during
spin extraction. This force will pull some air through the system
and past the heating unit, cooling coils and supplemental heater.
Generally, the airflow during centrifugal extraction is between 0
and about 5 percent of the airflow when the blower is turned on.
However, the rate of spin and the configuration of the airflow
system will ultimately determine the flow rate. The effect of
starting the system during the spin cycle is a more efficient
cycle, which results in lower retention of the cleaning fluid in
the articles at the end of spin cycle. This results in a lower spin
cycle time and lower dry cycle time which results in an overall
energy savings.
[0043] In another embodiment of the present invention, the blower
is turned on during the spin cycle to assist the natural air flow
past the components of the system. The blower is operated 20% or
less of the maximum airflow produced during the drying cycle. This
will enhance the evaporation of wash fluid during the spin cycle
with only an incremental energy expense.
[0044] Once the spin cycle has completed, the drying cycle is
begun. The dry cycle comprises engaging the heating unit, condenser
and cooling coils, and the blower. In a further embodiment of the
present invention, the supplemental heater is engaged as well.
These components are engaged until a satisfactory amount of wash
fluid has been removed from the articles. Generally, this will be
substantially all of the wash fluid such that the articles feel dry
to the touch.
[0045] In another embodiment, the system and method of the present
invention are used to dry water saturated clothes. This may be
accomplished, for example, in a traditional water based wash cycle
as is presently used in home based laundering. By dehumidifying the
air stream before it enters the wash drum, the air will be able to
pick up more moisture from the articles resulting in a decrease in
total dry time. The air then passes back through the cooling coils
and the water condenses to allow the air to be passed back through
the system and into the drum. In another embodiment of the present
invention, the air is optionally discharged from the machine
through a vent similar to a standard clothes dryer. Fresh air is
then pulled into the machine and passed through the system as
described above.
[0046] The method of drying articles described in the various
embodiments of the present invention is adaptable to a wide range
of article drying situations. While the preferred methods involve a
home based siloxane cleaning machine, the methods can be used
equally well in a commercial or coin-op machine. Furthermore, while
the cycles and dry times are disclosed for the preferred
embodiment, one skilled in the art will appreciate that these times
will vary for machines of larger or smaller size. A minimal amount
of experimentation will determine the appropriate cycle times for
any given machine size.
EXAMPLES
[0047] The drying cycle time typically ranges between about 15
minutes and about 60 minutes for a standard laundry load capacity
range between about 0.9 kg (2 lbs.) and about 6.8 kg (15 lbs.). The
sensible heat required to dry the clothes, which requires the
maximum power the machine needs, is between 430 watts and 6300
watts.
[0048] In another embodiment, the drying time is between 20 and 60
minutes for a capacity of between 6 and 12 lbs of articles. In this
case, the power required is between 1300 watts and 5200 watts. In
each of these cases, the power can easily be handled on a household
circuit with a maximum voltage of 240V and a maximum amp rating of
30 amps. In some embodiments, it can also be run on 220V, 20 amp or
220V, 30 amp or 110V 15-20 amp circuits. All of these outlet types
are typically available in homes for current cooking and drying
appliances, and require no additional installation
difficulties.
[0049] FIG. 5 shows the effect of Spin Speed during the spin cycle
on the residual moisture content (RMC) of wash fluid in the
articles at the end of the spin cycle. RMC can be used to measure
residual fluid content for any wash fluid and is not limited to
water. This data was generated using an 18 in diameter wash drum
spinning at 1000 rpm for 10 minutes. This produced a force of
approximately 225 g on the articles within the wash drum. The
figure shows that an acceleration of approximately 300 g is
required to attain asymptotic behavior, i.e. no change in retention
is observed for larger acceleration. Therefore, no energy or time
savings are realized by increasing the spin past this point. Also
shown is the effect of heating the system by starting compressor at
the start of spin cycle. An asymptotic gain of about 5% is obtained
for cotton. The earlier the asymptotic behavior begins, the better
time and energy savings that can be realized as a result of the
spin cycle. Therefore, by engaging the condenser coils during the
spin cycle, the energy needed by the motor to reach asymptotic
behavior is reduced.
[0050] FIG. 6 shows the effect of spin time on retention of wash
fluid in the articles at the end of the spin cycle. This data was
generated using a 22 in diameter drum spinning at 1000 rpm thereby
producing about 312 g of force. The initial conditions were 100%
cotton articles with 100% retention after the wash cycle, i.e. the
articles are completely saturated with water. Based on an average
of seven test runs, retention after an 8 minute heated spin cycle
is 28.2% with a standard deviation of 1.4% for a 100% cotton load.
This test demonstrates that an optimal spin time of 8 minutes is
required. Spin cycles of longer duration results in minimal
reduction of wash fluid.
1 Supp Duration Motor Pumps Heater Compressor Fans Total Power
Energy # Cycle (min) (W) (W) (W) (W) (W) (W) (kWh) 1 Initial RMC =
36% (5 min spin cycle) Spin 5 190 294 810 857 0 2151 0.18 Dry 41
100 294 810 857 140 2201 1.5 Spin + Dry Time= 46 Spin + Dry KWh=
1.7 2 Initial RMC = 30% (7 min spin cycle) Spin 7 190 294 810 857 0
2151 0.25 Dry 36 100 294 810 857 140 2201 1.3 Spin + Dry Time= 43
Spin + Dry kWh= 1.6 3 Initial RMC = 28% (8 min spin cycle) Spin 8
190 294 810 857 0 2151 0.29 Dry 35 100 294 810 857 140 2201 1.3
Spin + Dry Time= 43 Spin + Dry kWh= 1.6 4 Initial RMC = 28% (10 min
spin cycle) Spin 10 190 294 810 857 0 2151 0.36 Dry 35 100 294 810
857 140 2201 1.3 Spin + Dry Time= 45 Spin + Dry kWh= 1.6 5 Initial
RMC = 35% (8 min spin cycle, non heated) Spin 8 190 294 0 0 0 484
0.065 Dry 49 100 294 810 857 140 2201 1.8 Spin + Dry Time= 57 Spin
+ Dry kWh= 1.9
[0051] Table 1 demonstrates the impact of engaging the supplemental
heater, compressor and blower during the spin cycle and dry cycle
on spin and dry cycle time and energy requirements. This
demonstrates how critical the spin conditions are to total cycle
time and energy usage. As spin time increases, retention decreases
and consequently drying time and energy usage decrease. As shown in
FIG. 6, asymptotic behavior is reached at 8 minute spin time, after
which no reduction in retention is observed. This is observed in
Case 4 of Table 1. While the drying time remains the same, the
total cycle time and energy usage increases compared to Case 3. For
a non-heated spin, retention is about 35% higher, as shown in Case
5. Since the compressor and supplemental heater are switched on at
the start of drying and not at the start of spin, longer time is
required to reach the desired drum inlet air temperature.
Consequently, the drying time and total energy usage increases.
Data is based on the worst fabric case (maximum retention) of 100%
cotton load.
[0052] Although the present invention has been described with
reference to particular embodiments, it should be recognized that
these embodiments are merely illustrative of the principles of the
present invention. Those of ordinary skill in the art will
appreciate that the method of the present invention may be
implemented in other ways and embodiments. Accordingly, the
description herein should not be read as limiting the present
invention, as other embodiments also fall within the scope of the
present invention.
* * * * *