Information
-
Patent Grant
-
6293289
-
Patent Number
6,293,289
-
Date Filed
Monday, November 8, 199924 years ago
-
Date Issued
Tuesday, September 25, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 134 56 D
- 134 57 D
- 134 58 D
- 134 952
- 134 183
- 134 200
- 134 201
- 312 213
- 312 214
- 312 400
-
International Classifications
-
Abstract
A vent for a dishwasher provides a valve with dual actuation, either to be electrically actuated according to a cycle of the dishwasher so as to close during periods of high noise generation, typically the wash cycle, and opened during the dry cycle, or to be actuated independently of the cycle under pressure differences such as may be caused by interruption of the dishwasher cycle and opening and closing of the dishwasher door such as may cause a pressure surge as the introduced cool air is rapidly heated in the interior of the dishwasher.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
BACKGROUND OF THE INVENTION
The present invention relates to automatic dishwashing machines (dishwashers) and in particular to a dishwasher providing for low noise operation.
Dishwashers, such as those found in many homes, provide a closable chamber holding one or more racks into which eating utensils and cookware may be placed for cleaning. The chamber may include a door, opening to the front of the chamber to allow easy loading and unloading of the chamber, and closing, during a washing cycle, to prevent the escape of water which is sprayed within the volume of the chamber to wash the items placed in the racks.
Upon completion of the washing cycle, a drying cycle is initiated in which water is drained from the enclosure and moist air is discharged through an upper vent. Cool air pulled into the chamber through a lower vent rapidly dries the heated dishes.
Dishwashers can be quite noisy during the washing cycle, the noise coming from the agitated water, movement of the dishes, and the dishwasher mechanism of the water pump and motor. Some of this noise can be reduced by properly shrouding the chamber and dishwasher mechanism with sound absorbing materials. Nevertheless, a considerable amount of noise can still escape from even a properly shrouded chamber through the vents. Even a small vent area can allow a significant amount of noise to escape by diffraction.
One method of reducing noise escaping through the vent is to construct a vent which may close during the washing cycle and then open once the agitated water and pumping action has ceased to allow for proper drying of the dishes. Unfortunately, such closable vents can create a problem when the user interrupts the washing cycle to add a forgotten item for cleaning. When the dishwasher door is opened to insert the additional item, the chamber's volume of heated, moist air is replaced by colder air from the room. When the dishwasher door is reclosed, the hot dishes, racks and walls of the dishwasher together with the agitating hot water quickly heat the cold air causing it to expand. This expansion can force water from the dishwasher out through the door leading the user to believe the dishwasher has malfunctioned.
BRIEF SUMMARY OF THE INVENTION
The present inventors have recognized that a low noise vent for a dishwasher can be produced by properly combining an electrically actuated valve with a pressure actuated valve. The electrically actuated valve may be closed during the washing cycle and opened during the drying cycle, whereas the pressure actuated valve may provide relief of the surge pressure generated when the wash cycle is interrupted and started again.
Importantly, the pressure actuated valve may respond at an arbitrary time in the washing cycle independent of the cycle timer of the dishwasher while the electrically actuated valve may respond during the drying cycle when no triggering change in pressure occurs.
Specifically, then, the present invention provides a noise reducing vent for use with a dishwasher, the vent having an electrically actuated valve positioned to block passage of air from the sealable volume of the dishwasher to the outside of the dishwasher in a closed state and to allow the passage of air from the sealable volume to the outside of the dishwasher in an open state, the electrically actuated valve moving between the open and closed state in response to an electrical signal. The electrically actuated valve is combined with a pressure actuated valve positioned to block the passage of air from the sealable volume to the outside of the dishwasher in a closed state and to allow the passage of air from the sealable volume to outside the dishwasher in an open state, the pressure actuated valve moving from the closed to the open state in response to a predetermined excess of air pressure in the sealed volume over the air pressure outside the dishwasher.
It thus is one object of the invention to provide a vent that can be closed to reduce noise emitted from a dishwasher in response to normal cycle timing of the dishwasher and yet which prevents over-pressure of the sealed volume of the dishwasher such as may occur after interruptions of the washing cycle when the door of the dishwasher is opened.
The electrically actuated valve may employ a wax motor moving a valve element to cover or uncover an aperture leading between the sealable volume and outside of the dishwasher.
Thus it is another object of the invention to permit the use of an inexpensive yet slower wax motor for opening and closing the valve during the expected changes between cycles of the dishwasher while allowing response to extremely fast and unexpected pressure fluctuations caused by interruption of the washing cycle.
The predetermined pressure at which the pressure-actuated valve is triggered may be set to less than one inch of water.
Thus it is another object of the invention to provide a vent which actuates to rapidly suppress low surge pressures that might otherwise be sufficient to expel water from water traps that are used in some dishwashers to block air inlet vents during the washing cycle.
The pressure-actuated valve may be a caged ball seatable against a circular aperture leading between the sealable volume and the outside of the dishwasher. Alternatively, the pressure-actuated valve may include at least one flap hinged to movably cover an aperture leading between the sealable volume and outside the dishwasher.
Thus it is another object of the invention to provide extremely simple and robust valve mechanisms that may be pressure actuated at very low pressures.
The vent may include a common housing providing a first opening to the sealable volume and a second opening to outside the dishwasher, the first and second openings separated by a wall having a first and second aperture, each associated with one of the electrically actuated valves and pressure-actuated valves.
Thus it is another object of the invention to provide an integral vent unit such as may be mounted in the door of the dishwasher or the like.
The housing may include a second wall opposed to the first aperture having a third aperture therein and the electrically actuated valve may include a flexible boot having a valve surface sized to block the first aperture when the electrically actuated valve is actuated to block the first aperture, the flexible boot having side walls extending from the valve surface to an edge attached at the third aperture.
Thus it is another object of the invention to provide an electrically actuated valve that may be shielded from all contact material from the sealable volume of the dishwasher.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration, a preferred embodiment of the invention. Such embodiment does not necessary represent the full scope of the invention, however, and reference must be made to the claims herein for interpreting the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a simplified perspective view of a residential dishwasher showing the flow of cold and hot air into and out of the dishwasher when the washing cycle is interrupted and showing a vent path through the dishwasher door;
FIG. 2
is a graph plotting pressure versus time after a closing of the door of a dishwasher after interrupting of the washing cycle of the dishwasher of
FIG. 1
with the vent path closed to reduce noise and further showing resultant surge pressure as is reduced by the present invention;
FIG. 3
is a perspective cutaway view of a first embodiment of the present invention showing a housing providing a first aperture separating the inside and outside of the dishwasher, the first aperture provided with a ball and cage valve in an open state, the housing also providing a second aperture for use with an electrically actuated valve not shown in
FIG. 3
;
FIG. 4
is a cross-section along line
4
—
4
of
FIG. 3
showing the electrically actuated valve as may be positioned on the second aperture of
FIG. 3
per the present invention;
FIGS. 5
a
and
5
b
are alternative embodiments of the pressure actuated valve of
FIG. 3
in which an elastomeric flap is used to cover apertures leading between the inside and outside of the dishwasher,
FIG. 5
a
showing the valve in the closed state and
FIG. 5
b
showing the valve in the open state;
FIG. 6
is a fragmentary figure similar to
FIG. 3
showing an alternative embodiment with integrated pressure and electrically actuated valves; and
FIG. 7
is a fragmentary cross-sectional along line
7
—
7
of
FIG. 6
showing operation of the alternative embodiment of FIG.
6
.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to
FIG. 1
, a dishwasher
10
includes a generally rectangular cabinet
12
open at the front but sealable by a hinged door
14
at that opening to define an enclosed volume
16
. The volume
16
may hold one or more racks
18
to support dishes
20
or other items to be washed. The door
14
may include a vent
22
allowing passage of steam and air from the enclosed volume
16
to the outside of the dishwasher
10
as indicated by arrow
24
.
Referring now to
FIGS. 1 and 2
, when the door
14
of the dishwasher
10
is opened as shown in
FIG. 1
after initiation of the dishwashing cycle, heated air
26
escapes from the volume
16
to be replaced by cooled air
28
from the room. As shown in
FIG. 2
, when the door
14
is closed again at time to and if the vent
22
is closed to reduce sound level outside of the dishwasher
10
, then a rapid pressure spike
30
occurs caused by the heating of the air held within the enclosed volume
16
by the already warmed dishes
20
and walls of the volume
16
. At time t
1
, when agitation of hot water is resumed, the pressure rises to a spike
32
that may be sufficient to force water from the volume
16
past the door
14
.
Referring now to
FIG. 3
for this reason, the present invention provides a vent
22
, having a housing
34
such as may be a generally rectangular, parallelepiped having a first opening
36
communicating with the sealable volume
16
of the dishwasher
10
to allow the passage of air and steam
38
into the housing
34
. A second opening
40
in the housing
34
communicates directly with the air outside of the dishwasher
10
allowing the passage of air and steam
38
from the housing
34
out to the outside air.
Dividing the interior volume of the housing
34
is a wall
42
such as may be positioned horizontally and which has two apertures
44
and
46
cut therein. Air and steam
38
flowing into the first opening
36
must pass through one of apertures
44
and
46
so as to continue and flow out through opening
40
.
A ring-shaped valve seat
47
encircles aperture
44
. On the top edge of the valve seat a lightweight ball
48
may rest. The upper half of the ball is encircled by a cylindrical cage
50
preventing the ball from moving substantially off of the axis of the valve seat
47
.
When the pressure of the air within the volume
16
of the dishwasher
10
is substantially equal to or less than the ambient pressure, the ball
48
rests on the valve seat
47
sealing aperture
44
and preventing the escape of sound through the aperture
44
. Alternatively, when the pressure within the volume
16
rises such as in pressure spike
30
and
32
shown in
FIG. 2
, the ball rises allowing passage of air and steam
38
through aperture
44
.
The size and weight of the ball
48
and the area of the valve seat
47
may be adjusted so that this pressure threshold occurs at approximately one inch of water. Accordingly, referring again to
FIG. 2
, the pressure spikes
30
and
32
are reduced to levels
31
and
33
insufficient to eject water from the volume
16
of the dishwasher
10
. Instead, pressurized air and steam
38
will overcome the weight of the ball
48
and pass through the aperture
44
to escape out opening
40
.
Referring now to
FIGS. 3 and 4
, positioned across from the wall
42
and aperture
46
, is parallel wall
51
having an aperture
52
coaxial with aperture
46
. Wall
51
serves to support electrically actuated valve
54
(shown only in FIG.
4
). The electrically actuated valve
54
includes a flexible boot
56
having a generally planar valve surface
58
sized to block the aperture
46
when the valve surface
58
is pressed against aperture
46
thereby obstructing the flow of air and steam
38
. The valve surface
58
is pressed against aperture
46
(or withdrawn therefrom) by a plunger
60
fitting within the boot
56
and adjacent to an inner side of valve surface
58
opposite the aperture
46
. The plunger
60
in turn connects to a shaft
62
of a wax motor
64
. Operating according to well-known principals, the wax motor
64
moves the shaft
62
toward the aperture
46
when electrical current is conducted through terminals
66
of the wax motor
64
to heat an internal element (not shown), melt a contained wax material causing expansion of that material against the shaft
62
. The terminals
66
are connected to a cycle timer (not shown) of conventional design to provide current during the wash cycle and thereby to close the aperture
46
during that time of high noise generation. It will be understood from this description that an inverted logic may also be used in which the presence of current from the cycle timer opens the aperture
46
or wherein a bi-state mechanism is adapted where current alternately opens then closes the aperture
46
.
The boot
56
has upwardly extending sidewalls
68
terminating at a radially extending flange
70
, the latter which fits into a depressed rim
72
ringing the aperture
52
.
It will be understood that the depressed rim
72
is not required and that flange
70
could sit on top of wall
51
. A corresponding flange plate
74
on the wax motor
64
sandwiches the flange
70
between the depressed rim
72
and the flange plate
74
sealing the boot against the wall
51
and protecting the wax motor
64
from water and steam
38
. The flange plate
74
also serves to support the wax motor
64
against the wall
51
.
Referring to
FIGS. 5
a
and
5
b
, the pressure actuated valve need not be limited to the ball and cage design shown in
FIG. 3
but may include generally any well known pressure actuated valve including diaphragm, umbrella, and flapper valves known in the art. In one such alternative embodiment, aperture
44
is separated into two portions
44
a
and
44
b
as divided by diametric support bar
80
. An elastomeric flap
82
is attached at its center to the diametric support bar
80
to extend over the apertures
44
a
and
44
b
and in a relaxed state to lie horizontally atop wall
42
sealing in noise. Pressure from air and steam
38
above a designated threshold, as shown in
FIG. 5
b
, causes an upward flexing of the edges of the elastomeric flap
82
away from the apertures
44
a
and
44
b
allowing passage of air and steam therethrough. The weight and elasticity of the flap
82
and the area of the apertures
44
a
and
44
b
may be adjusted so as to provide an arbitrary pressure threshold for opening and the necessary clear aperture when the flap
82
does open. The ability to subdivide the aperture
46
allows great flexibility in the selection of different elastomeric interior materials.
Referring now to
FIGS. 6 and 7
in an alternative embodiment, the separate pressure actuated valve formed by ball
48
and valve seat
47
, operating to open and close aperture
44
, and electrically actuated valve
54
operating to open and close aperture
46
, (all shown in
FIG. 3
) may be combined so that only a single aperture
90
is cut within wall
42
providing a single path through wall
42
between openings
36
and
40
.
The aperture
90
may be covered by a generally rectangular flap
92
lying in a closed state atop wall
42
over aperture
90
and hinged at one end by knuckle
94
supported by horizontally opposed pintels
96
so that the flap
92
may rotate about the knuckle
94
and rise away from aperture
90
under the same excess pressure conditions that lift ball
48
from valve seat
47
(shown in FIG.
3
). In this regard, the weight of the flap
92
is adjusted to provide for similar pressure relief as provided by ball
48
and seat
47
or flap
82
and aperture
44
.
Extending oppositely from knuckle
94
away from flap
92
is a hook
98
curving upward from wall
42
so as to be behind downwardly extending finger
100
attached to shaft
102
of wax motor
104
. When current is not provided to the wax motor
104
, the downward finger
100
moves from a first position
103
to a second position l
05
engaging hook
98
to raise flap
92
away from aperture
90
. When the wax motor
104
receives current, the downward extending finger
100
returns to the first position
103
in which hook
98
does not engage downward finger
100
allowing for the full range of motion of the flap
92
between open and closed state.
Thus, it will be understood that in the first position
103
, the flap
92
is free to move in response to pressure but in the second position, the flap is raised away from aperture
90
independent of any excess pressure but in response to the removal of the electrical signal from the dishwasher timer.
As will be understood in the art, the wax motor
104
may be replaced with other electrical actuators including but not limited to solenoids and motors and that the signal from the dishwasher may be either a current or lack of current as is necessary for correct operation of the vent
22
.
The above description has been that of a preferred embodiment of the present invention, it will occur to those that practice the art that many modifications may be made without departing from the spirit and scope of the invention. In order to apprise the public of the various embodiments that may fall within the scope of the invention, the following claims are made.
Claims
- 1. In a dishwasher providing a sealable volume containing dishes during their washing, a vent comprising:a pressure actuable valve element movable between an open and closed state and positioned to block the passage of air from the sealable volume to outside the dishwasher in the closed state and to allow the passage of air from the sealable volume to outside the dishwasher in the open state, the pressure acutable valve element moving from the closed to the open state in response to a predetermined excess of air pressure in the sealable volume over the air pressure outside the dishwasher; and an electrical actuator movable between a first and second position and linked with the pressure actuable valve element so as allow free movement of the pressure actuable valve element between the open and closed state in response to the predetermined excess of pressure, when the electric actuator is in the first position and to hold the pressure actuable valve element in the open state when the electric actuator is in the second position; whereby absent an signal from the dishwasher actuating the electric actuator and absent excess of pressure in the sealable volume, noise emanating from the sealable volume is blocked.
- 2. The vent as recited in claim 1 wherein the predetermined excess of pressure is less than one inch of water.
- 3. The vent as recited in claim 1 wherein the electric actuator is a wax motor.
- 4. In a dishwasher providing a sealable volume containing dishes during their washing, a vent comprising:an electrically actuable valve positioned to block the passage of air from the sealable volume to outside the dishwasher in a closed state and to allow the passage of air from the sealable volume to outside the dishwasher in an open state, the electrically acutable valve moving between the open and closed state in response to an electrical signal; and a pressure actuable valve positioned to block the passage of air from the sealable volume to outside the dishwasher in a closed state and to allow the passage of air from the sealable volume to outside the dishwasher in an open state, the pressure acutable valve moving from the open to the closed state in response to a predetermined excess of air pressure in the sealable volume over the air pressure outside the dishwasher; whereby absent an electrical signal from the dishwasher to the electrically actuable value and an excess of pressure in the sealable volume, noise emanating from the sealable volume is blocked.
- 5. The vent as recited in claim 4 wherein the predetermined excess of pressure is less than one inch of water.
- 6. The vent as recited in claim 4 wherein the pressure acutable valve includes a caged ball seatable against a circular aperture leading between the sealable volume and outside the dishwasher.
- 7. The vent as recited in claim 4 wherein the pressure acutable valve includes at least one flap hinged to movably cover at least one aperture leading between the sealable volume and outside the dishwasher.
- 8. The vent as recited in claim 7 wherein the pressure actuable valve includes at least two elastomeric flaps covering two apertures.
- 9. The vent as recited in claim 4 wherein the electrically acutable valve includes a wax motor moving a valve element to cover and uncover an aperture leading between the sealable volume and outside the dishwasher.
- 10. The vent as recited in claim 4 including a common housing providing a first opening to the sealable volume and a second opening to outside the dishwasher, the first and second openings separate by a wall having a first and second apertures;wherein the electrically acutable valve is positioned to block and allow that passage of air through the first aperture and wherein the pressure actuable valve is positioned to block and allow the passage of air through the second aperture.
- 11. The vent as recited in claim 10 including further a second wall opposed to the first apertures and having a third apertures and wherein the electrically actuable valve includes a flexible boot having a valve surface sized to block the first apertures when the electrically actuable valve is actuated to block the first aperture, the flexible boot having sidewalls extending from the valve surface to an edge attached to the third apertures;whereby remaining portions of the electrically actuable valve are shielded from contact with materials from the sealable volume of the dishwasher.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
4247158 |
Quayle |
Jan 1981 |
|
5572869 |
Schantz et al. |
Nov 1996 |
|
5660195 |
Taylor, Jr. et al. |
Aug 1997 |
|
5836324 |
Johnson et al. |
Nov 1998 |
|
6138692 |
Kobos et al. |
Oct 2000 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2937589 |
Apr 1981 |
DE |