U.S. patent number 3,854,998 [Application Number 05/392,932] was granted by the patent office on 1974-12-17 for fluid powered ultrasonic washing, rinsing, and drying system for a dishwasher.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to James W. Jacobs.
United States Patent |
3,854,998 |
Jacobs |
December 17, 1974 |
FLUID POWERED ULTRASONIC WASHING, RINSING, AND DRYING SYSTEM FOR A
DISHWASHER
Abstract
A fluid-powered ultrasonic washing, rinsing and drying system
for a dishwasher wherein an ultrasonic frequency generator is
provided in the form of a cylindrical nozzle located on a centrally
disposed tower in the washing compartment. The tower has an axial
water pump driven inner detergent water solution feed line and an
axial flow air-vapor pump driven outer vapor and compressed air
feed line which draws vapor from the compartment and exits it at
high velocity from the cylindrical nozzle to reflect off a
resonator ring primary surface and a distributor secondary surface
in a spherical wave form to the compartment.
Inventors: |
Jacobs; James W. (Dayton,
OH) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
23552610 |
Appl.
No.: |
05/392,932 |
Filed: |
August 30, 1973 |
Current U.S.
Class: |
134/191; 134/193;
239/425; 134/1; 134/198 |
Current CPC
Class: |
A47L
15/16 (20130101); G10K 5/02 (20130101); A47L
2601/17 (20130101) |
Current International
Class: |
A47L
15/13 (20060101); A47L 15/00 (20060101); G10K
5/00 (20060101); G10K 5/02 (20060101); B08b
003/02 () |
Field of
Search: |
;134/1,184,191,193,198
;239/425 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Bleutge; Robert L.
Attorney, Agent or Firm: Barthel; Edward P.
Claims
I claim:
1. A dishwasher comprising; a casing defining a washing chamber
having a sump and an access opening, a plurality of utensil
supporting rack means secured to said dishwasher casing, a
combination vapor-air blower and liquid supply pump including an
inner liquid pump housing and outer vapor blower housing
concentrically spaced therefrom so as to extend vertically upwardly
from said sump, said inner housing enclosing a liquid circulating
impeller and said outer housing enclosing vapor-air impeller,
motive means for driving both said impellers, liquid passage means
connecting said sump with said inner pump housing, vapor-air
passage means connecting said washing chamber with said outer
blower housing, means for distributing liquid in said chamber for
washing dishes or the like, said liquid distributing means
including a vertical column mounted on said blower outer housing
and in fluid communication therewith, said column extending
upwardly to a central part of said chamber, said column having an
ultrasonic generator supported thereon, said generator including a
lower dish-shaped plate having a concave surface facing upwardly,
and an upper inverted dish-shaped plate positioned in concentric
spaced relation above said lower plate, whereby a 360.degree.
Venturi nozzle opening is provided between the adjacent perimeters
of said plates; a vertical liquid supply tube positioned within
said column such that its lower end is in communication with said
pump inner housing, upper and lower cup-shaped liquid distributor
heads having their open ends in sealed contact with the central
portion of said upper and lower plates respectively, providing
upper and lower liquid distributing cavities; said upper and lower
heads concentrically supported on said upper and lower plates
respectively, the curved outer surfaces of which form secondary
dome-like reflecting surfaces, means for supplying liquid to each
of said distributor cavities from said liquid supply tube, each
said distributor head having apertures therein for directing liquid
spray into said washing chamber, a ring fixedly mounted in
outwardly spaced concentric relation with respect to said upper and
lower plates such that said ring is symmetrically located with
respect to a horizontal plane bisecting said Venturi nozzle, said
ring having its inner annular face providing a primary reflecting
surface in opposed facing relation with said Venturi nozzle such
that ultrasonic vapor-air waves emitted by said Venturi nozzle are
reflected from said ring primary surface onto said secondary upper
and lower reflecting surfaces whereby ultrasonic vapor-air waves
are directed outwardly in conjunction with said liquid spray into
said washing chamber for impinging on utensils being cleaned in
said racks.
2. A dishwasher comprising; a casing defining a washing chamber
having a sump and an access opening, a plurality of utensil
supporting rack means secured to said dishwasher casing, a
combination vapor-air blower and liquid supply pump including an
inner liquid pump housing and outer vapor blower housing
concentrically spaced therefrom whereby said housings extend
vertically upwardly from said sump, said inner housing enclosing a
liquid circulating axial impeller and said outer housing enclosing
vapor-air axial impeller, an electric motor having a common shaft
for driving both said impellers, liquid passage means connecting
said sump with said inner pump housing, a vapor-air return duct
extending vertically downwardly along one wall of said chamber and
thence inwardly beneath said sump wall connecting said washing
chamber with said outer blower housing, heating means positioned in
the lower portion of said vapor-air duct, means for distributing
liquid in said chamber for washing dishes or the like, said liquid
distributing means including a vertical column mounted on said
blower outer housing and in fluid communication therewith, said
column extending upwardly to a central part of said chamber, said
column having an ultrasonic generator supported thereon, said
generator including a lower plate member having a concave inner
surface facing upwardly, an upper inverted identical plate member
positioned in concentric spaced relation above said lower plate
member having a concave inner surface facing downwardly, whereby a
360.degree. Venturi nozzle opening is provided between the adjacent
perimeters of said plate members; a vertical liquid supply tube
positioned within said column, said supply tube having its lower
end supported on said pump inner housing, upper and lower
cup-shaped water distributor heads having their open ends in sealed
contact with the central portion of said upper and lower plates
respectively, providing upper and lower liquid distributing
cavities; said upper and lower heads concentrically supported in
mirror image fashion on said upper and lower plates respectively
whereby their curved outer surfaces form secondary upper and lower
reflecting surfaces, means for supplying liquid to each of said
distributor cavities from said liquid supply tube, each said
distributor head having apertures therein for directing liquid
spray into said washing chamber, a ring fixedly mounted on and in
outwardly spaced concentric relation with respect to said upper and
lower plates such that said ring is symmetrically located about a
horizontal plane bisecting said Venturi nozzle, said ring having
its inner annular face providing a primary reflecting surface in
opposed facing relation with said Venturi nozzle such that
ultrasonic vapor-air waves emitted by said Venturi nozzle are
reflected from said ring primary surface onto said secondary upper
and lower reflecting surfaces whereby the ultrasonic vapor-air
waves are directed outwardly in conjunction with said liquid spray
into said washing chamber for impinging on utensils being cleaned
in said racks.
3. A dishwasher comprising; a casing defining a washing chamber
having a sump and an access opening, a plurality of utensil
supporting rack means secured to said dishwasher casing, a
combination vapor-air blower and liquid supply pump including an
inner liquid pump housing and outer vapor blower housing
concentrically spaced therefrom so as to extend vertically upwardly
from said sump, said inner housing enclosing a liquid circulating
impeller and said outer housing enclosing vapor-air impeller,
motive means for driving both said impellers, liquid passage means
connecting said sump with said inner pump housing, vapor-air
passage means connecting said washing chamber with said outer
blower housing, means for distributing liquid in said chamber for
washing dishes or the like, said liquid distributing means
including a vertical column mounted on said blower outer housing
and in fluid communication therewith, said column extending
upwardly to a central part of said chamber, said column having an
ultrasonic generator supported thereon, said generator including a
lower dish-shaped plate and an upper inverted dish-shaped plate
positioned in concentric spaced relation above said lower plate,
whereby a 360.degree. cylindrical Venturi nozzle opening is
provided between the adjacent perimeters of said plates; a vertical
liquid supply tube positioned within said column such that its
lower end is in communication with said pump inner housing, a water
distributor head concentrically supported on said upper plate
providing a liquid distributing cavity; said distributor head
having a curved outer surface which forms a secondary dome-like
ultrasonic reflecting surface, means for supplying liquid to said
liquid distributing cavity from said liquid supply tube, said
distributor head having apertures therein for directing liquid
spray into said washing chamber, a ring rotatably mounted in
outwardly spaced concentric relation with respect to said Venturi
nozzle such that said ring is symmetrically located about a
horizontal plane bisecting said Venturi nozzle, said ring's inner
annular face formed with a stepped configuration defining primary
ultrasonic reflecting surfaces including a plurality of crests and
nodes in opposed facing relation with said cylindrical Venturi
nozzle, the radial dimensions from said cylindrical Venturi nozzle
to said primary stepped reflecting surfaces resulting in a range of
ultrasonic vapor-air wave frequencies being reflected from said
primary surface onto said secondary dome-like reflecting surface
whereby the ultrasonic vapor-air waves are directed outwardly in
conjunction with said liquid spray into said washing chamber for
impinging on utensils being cleaned in said racks.
4. A dishwasher comprising; a washing chamber having a sump, a
utensil supporting rack in said washing chamber, a vapor blower and
a liquid pump assembly supported below said sump, motive means for
driving said blower and said pump, liquid passage means connecting
said sump with said pump, vapor passage means connecting said
washing chamber with said blower, means for distributing vapor and
liquid in said chamber for washing dishes or the like, said
distributing means including a vertical column extending upwardly
into said washing chamber, said column having an ultrasonic
generator supported thereon, said ultrasonic generator including a
360.degree. Venturi nozzle for distributing vapor therefrom, means
for supplying vapor to said Venturi nozzle from said blower through
said column, upper and lower liquid distributor heads concentric to
said 360.degree. Venturi nozzle and having curved outer surfaces
forming vapor reflecting surfaces, means for supplying liquid to
each of said distributor heads from said pump through said column,
each of said distributor heads having apertures therein for
directing liquid into said washing chamber, a reflector ring
mounted in outwardly spaced concentric symmetrical relation to said
360.degree. Venturi nozzle, said ring providing a primary
reflecting surface in opposed facing relation with said Venturi
nozzle such that vapor emitted by said Venturi nozzle is reflected
from said primary surface onto said curved outer surfaces of said
liquid distributor heads whereby ultrasonic vapor waves are
generated and directed outwardly and combined with liquid exiting
from said distributor head apertures so as to be directed into said
washing chamber for impinging on utensils being cleaned in said
rack.
Description
This invention relates to dishwashing machines, and particularly to
a dishwasher having a fluid-powered ultrasonic washing system.
It is known to use ultrasonic means for agitating liquid washing
solution into vibrations to provide mechanical energy within a
dishwashing chamber. It is an object of the present invention to
provide a sonic wave generator for a dishwashing machine having a
cylindrical nozzle for producing an air-vapor jet flow together
with a resonating cavity ring surrounding the cylindrical nozzle
which cooperates with liquid distribution means coaxial with the
jet flow and displaced axially therefrom.
It is another object of the invention to provide ultrasonic
dishwashing machines having an axial flow liquid pump which draws
water from the sump and delivers it to upper and lower distributors
of an ultrasonic generator together with an axial flow vapor pump
which draws vapor from the washing compartment for subsequent
heating and delivering it in a compressed state to the ultrasonic
generator for exiting from a cylindrical nozzle and for echoing off
a primary resonator ring surface and a secondary dome-shaped
distributor surface in a spherical wave to the compartment.
These and other objects and advantages of the present invention
will be apparent from the following description, reference being
had to the accompanying drawings wherein preferred forms of the
present invention are clearly shown.
In the drawings:
FIG. 1 is a generally schematic representation of a dishwasher
incorporating the invention;
FIG. 2 is an enlarged fragmentary vertical sectional view of the
distributor head showing the spray means in relation to the sonic
generator cylindrical nozzle and resonator ring;
FIG. 3 is a vertical sectional view through the lower portion of
the spray tower showing the dual pump assembly;
FIG. 4 is a schematic wiring diagram suitable for use with the
dishwasher of this invention;
FIG. 5 is a sequence chart for the disclosed control circuit;
FIG. 6 is a side elevational view partly in section of a modified
sonic generator and distributor head for the washing machine;
and
FIG. 7 is a horizontal section taken on the lines 7--7 of FIG.
6.
In accordance with this invention and with reference to FIG. 1, a
dishwasher 10 having an outer cabinet 11 including a top 12, side
panels, one of which is partially indicated at 13; a rear panel 14
and a base panel 16 adapted to include the dishwashing chamber or
tub shown generally at 18. The dishwashing chamber is a generally
box-like receptacle having a depressed bottom defining a sump 20.
The dishwashing chamber 18 has an access opening 22 in the front
wall thereabove the lower front panel 23 which is closed by a
dishwasher door shown generally at 24. The door 24 may be hinged to
the side panels of the dishwasher as at 25 and latched in any
conventional manner so as adapted to be opened by the handle 26. A
water-tight connection between the dishwashing chamber 18 and the
door 24 such as gasket 28 may be provided and arranged about the
periphery of the opening 22.
The dishwasher includes a machine or motor compartment 30 beneath
the sump 20 closed by the cover panel 23 across the front portion
on the machine compartment and is supported on bottom panel 16
which defines a toe space at the bottom front of the appliance. The
bottom wall 32 of the sump is sloped or tapered to direct fluid
within the dishwashing chamber to an opening 34 in one portion of
the sump wall. Underlying the opening is a drain-and-recirculate T
valve 36 operated by a solenoid 38. Valve 36 is arranged to
selectively direct water from the sump to a drain line 40 or to a
pump inlet conduit 41.
A conventional timer 42 may be set for a given washing cycle at
which point water will be introduced into the sump by means of a
fill or supply valve 44. Connected to the sump of the dishwasher,
as best shown in FIG. 3, is a vapor and water distributing system
including an axial flow liquid pump 46 and an axial flow air-vapor
pump 47 driven by a motor 48. The outlet 50 of the water pump is
connected by means of a vertical inner detergent water solution
feed pipe 52 to distributor means 54 with the motor 48 mounted in
the vertical position on the motor shaft 56 extending upwardly
through a cylindrical opening 58 mounting shaft seal 74 into the
pump housing 60 where pump impeller 62 is attached to shaft 56 by
means of a cone-shaped bolt 64 and a clamp washer 66. Rotation of
the impeller with the T valve 36 in its pump inlet position will
cause fluid to be drawn through conduit 41 and impelled to lift
upwardly into the detergent water solution feed pipe 52, as shown
by the solid line arrows in FIG. 3, to set up a water recirculating
action to the pipe 52. The drainage action occurs via conduit 41.
When the T valve 36 is in its drain position, fluids in the sump 20
will flow by gravity through it to a suitable drain via conduit
40.
A concentrically conforming outer blower housing 70 is formed
around the pump housing 60 for receiving an axial flow blower 72
also mounted on the motor shaft 56 with shaft seal 74 positioned to
seal the axial flow pump impeller 62 from the subjacent blower
72.
As seen in FIG. 1, an air-vapor return upstanding duct 80 is
included between the rearwardly offset portion 81 of the back wall
15 and the chamber rear wall 82, and communicates with the chamber
through an opening 84 in the rear wall thereof -- an inverted
cup-like deflector 86 serving to prevent spray from entering the
duct 80. The vapor return duct 80 extends vertically downwardly and
thence inwardly beneath the sump wall 32 to an inlet 87 in the
axial flow blower housing 70 wherein heated air-vapor, as indicated
by the wavy arrows in FIG. 3, is returned to the blower. Heating
means in the form of a plurality of electrical resistance heaters
90 are arranged in the lower portion 92 of the air-vapor duct
underlying the sump and isolated by wire mesh screens 94 and 96 for
heating the returned air-vapor prior to its entry into the axial
flow blower housing.
As viewed in FIGS. 1 and 2, a sonic energy generator 100 is
supported on the upper end of a central tower or column 102. The
tower 102 is shown formed as an integral reduced portion of the
blower housing and extends upwardly therefrom through an opening
104 in the concentric raised dome 106 of the sump wall 32, which
opening is suitably sealed as by rubber-like seal ring 108. The
sonic energy generator 100 includes a lower dish-like plate 110
having central depending hub 112 supported on a reduced diameter
extension 114 of the tower 102. An upper inverted dish-like plate
116 of the generator is supported by central hub 117 on the inner
feed pipe 52 in spaced relation from the lower plate 110 whereby a
360.degree. outwardly flowing cylindrical venturi sectioned nozzle
118 is defined therebetween.
As seen in FIG. 2, the generator upper plate supports an upper
cup-shaped water distributor head 120 in concentric fashion thereon
for receiving a portion of the water exiting from axial outlet 122
of the water feed pipe 52. A plurality of spray ports 124 are
evenly spaced around the upper distributor head 120 for the exiting
of the water into the washing chamber. In a like manner, a lower
cup-shaped water distributor head 126 is supported in a concentric
inverted manner on tower 102 such that its upper open end is sealed
against the underside of lower plate 110. A radial outlet 128 is
provided in feed pipe 52 and extends outwardly through an opening
130 in the tower 102 for the flow of a portion of the water into
the lower head 126 and thence, outwardly through spray ports 132
into the washing chamber 18 to direct a water vapor-air mixture
over utensil supporting baskets 134 and 136 located above and below
the distributor 54.
A resonator ring, shown at 140 in FIGS. 1 and 2, is positioned in
spaced concentric relation to the nozzle 118 such that it is
symmetrically located on the horizontal plane which bisects the
cylindrical nozzle 118. As seen in FIG. 2, the resonator ring 140
body portion 142 has an inwardly concave-convex cross section
forming an inner arcuate primary surface 143, provided with upper
and lower outwardly canted flanges 144 and 146, respectively. The
resonator ring is supported by a plurality of arcuate support wires
extending from the upper plate 116 and secured to the outer surface
of upper flange 144 as shown for example by the wire 148 in FIG.
2.
As seen by the wavy arrows in FIG. 2, when a water vapor and heated
air mixture, compressed in the upwardly converging concentric feed
space 150 formed by the inner water feed pipe 52 and outer column
102, is directed into the conoid-shaped space 152 of the sonic
energy generator 100, the vapor-air mixture is emitted from the
cylindrical nozzle 118 in the form of an ultrasonic fluid jet that
impinges on the primary annular curved resonator surface 143. The
vapor-air mixture exiting at ultrasonic velocity from the
cylindrical nozzle echos off the resonator ring and reflects off
the distributor heads in a spherical wave form to mix with the
washing liquid from the orifices 124 and 132 for impingement on the
utensils in the compartment. The primary surface 143 of the ring is
adapted to reflect the air-vapor mixture in both an upwardly and
downwardly divergent manner for impinging on the secondary curved
surfaces of the dome-shaped upper and lower distributors 120 and
126, respectively to produce high frequency acoustical vibrations
or ultrasonic waves in the region between the secondary surfaces
120, 126 and the reflector ring annular surface 143.
In the form shown, the radial distance between the primary
reflective surface 143 and the secondary surfaces 120 and 126 of
the upper and lower dome-shaped distributors rspectively, is of the
order of one wave length. The secondary surfaces, thus, reflect the
sonic waves in a divergent manner such that they are distributed
over a wide angle within the dishwashing chamber 18 for further
reflection off dishes and utensils being cleaned and off the side,
top and bottom walls of the chamber.
Referring now to FIG. 4, a control circuit is set forth embodying
in a representative fashion the major control concepts of this
invention. The circuit includes a domestic household electrical
supply indicated by L1 and L2 for energizing the components of the
control circuitry including a solenoid winding 158 for actuating
the normally closed drain valve 36 by solenoid 38 and a solenoid
winding 160 for actuating the water supply fill valve 44. These
various components and their respective circuits are actuated by a
plurality of timer switches which are cam actuated by a timer shaft
162 driven by a timer motor 164. The control circuit further
includes the duct heater 90 and the motor 48 for driving the pumps
46 and 47. A holding circuit for starting the normal wash cycle
includes start relay 168 operating start switch 170. The circuit
may include a door switch 172 which is closed simultaneously with
the closing of the dishwasher door. A push-pull timer switch 174 is
utilized for initiating the normal washing cycle thus energizing
the timer motor 164. A detergent selector switch plate 176
operating between a pair of contacts 7 and 8 to actuate a heater
178 is used to operate the detergent dispenser 179.
In operation, when the timer push-pull switch 174 is closed,
assuming the door switch 172 is also closed, the timer motor 164 is
energized to initiate the washing, rinsing and drying cycle. The
drain solenoid 158 opens via timer contact 1 to allow any water in
the sump to flow by gravity to the drain 34 after which the drain
solenoid 158 closes. The fill valve 44 is energized by solenoid 160
via timer contacts 9 to fill the sump with water. Next, the motor
48 is energized through timer contact 4 of by-pass switch 180 and
the axial flow liquid pump 46 together with the axial flow vapor
pump 47 begin to operate drawing water mixed with detergent
(previously dumped into the sump upon closing door 24) from the
sump and delivering it to the distributors 120 and 126 in the
ultrasonic generator 100. At the same time, the axial flow vapor
pump 47 draws vapor (air) from the compartment 18 to the return
duct 80 and over the heater 90, now energized via timer contact 2,
and delivers the heated and compressed vapor to the ultrasonic
generator 100.
Vapor exiting at high velocity from the cylindrical nozzle 118
echoes off the resonator ring primary surface 143 (properly spaced
to provide the ultrasonic frequency desired) and reflects off the
secondary curved surfaces of the distributors 120 and 126 in a
spherical wave form to the washing compartment. The liquid solution
is mixed with the vapor at the distributor orifices 124 and 132.
The system thus proceeds through the various wash and rinse cycles.
In the drying cycle, the drain solenoid 158 is energized allowing
the water to flow to the drain whereby only heated vapor is
circulated throughout the dishwashing chamber 18.
FIGS. 6 and 7 disclose a modified form of the sonic energy
generator 100' wherein a resonator ring 190 is supported on the
upper distributor head 120' by means of a plurality of radial
support means, such as wires shown at 192, having their outer ends
fixedly secured as by welding to the outer surface of the ring 190.
The inner ends of the wires 192 are secured to a support bearing
193 located on the vertical axis of the distributor head 120' which
enables the ring to drivingly rotate about the principal vertical
axis of the ultrasonic generator upper 116' and lower 110' plates
by the exiting high velocity vapor-air and water solution.
As seen in FIG. 7, the inner surface of the ring 190 is formed in
an arcuate stepped or saw tooth configuration 194 such that the
radial dimensions from the cylindrical nozzle 118 to the crests 196
and nodes 198 of the stepped surface 194 together with all
intermediate points therebetween thereby providing a range of
ultrasonic frequencies having wave lengths that vary from
.lambda..sub.1 at the crests 196 to .lambda..sub.2 at the nodes
198. Thus, a bandwidth of ultrasonic frequencies is generated to
improve the coupling of the energy to the dishes and utensils being
cleaned and the interior of the dishwashing chamber 18 is swept by
the resulting rotating field of ultrasonic energy to thereby
improve the cleansing, rinsing and drying actions.
It will be noted that the cup-shaped distributor heads 120' and
126' provided with apertures 132' are identical to corresponding
parts in FIG. 2. While a recirculating dishwashing system is
disclosed, it will be apparent that applicant's invention is
suitable for a non-circulating or "straight through" automatic
dishwasher system.
The present system for a typical example for a domestic dishwasher
would require about 0.5 gallons of water per fill with a vapor-air
circulation rate of about 500 cubic feet per minute. It is intended
that the ultrasonic operating frequencies within the range of 500
and 100,000 cycles per second is suitable Also the washing liquid
could be a water detergent solution to combine with the ultrasonic
vapor-air so as to create a fog-like mixture operative to clean the
utensils.
While the embodiment of the present invention constitutes a
preferred form, it is to be understood that other forms might be
adopted.
* * * * *