Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND DISCUSSION
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Modern automatic dishwashers generally inelude an
automatic control of in-flow of water from the water supply
into the machine. This automatic control is typically
provided by a timer whieh eauses a fill valve t.o be opened at
the appropriate point in the machine cycle for a predetermined
time interval, allowing water flow into the dishwasher
tube over this interval. Such automatie eontrol creates the
possibility of a flooding condition being reached in which
water overflows the level of the tub and out of the machine
where it may eause damage. Such a flooding condition may occur
for a variety of reasons, such as failure of the fill valve,
over pressure line eonditions, clogged dishwash drain, e-tc.
Many dishwasher designs aecordingly provide for some
arrangement for flood control.
In some of these designs, a fail~safe mechanism is
incorpora-ted into the eleetrieal eontrol which will eorreet
flood level eonditions oecurring during the maehine cycle.
Some failure mo~es, however, sueh as a mechanieal failure
of -the valve may oeeur at any time, not only during the
machine operation. Thus 24-hour flood controI protection
is a desirable feature in such machines.
In U.S. Patent No. 3,894,555, R.E. Payne, issued
July 15, 1975, a flood control feature is disclosed
in which a float is moun-ted within the dishwasher tub
which acts to deenergize a secondary electrically
operated valve installed downstream from the fill valve.
If a flood level occurs in the tub, the float rises to the
flood level and aets to operate an associated switch to open
the circui-t -to the secondary flood con-trol valve, causing
elosing of the valve and eessation of flow to the tub~
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9D-DW-135~5
The secondary valve adds significantl~ to the
expense of manufacture, since an aaditional relatively costly
electrically operated valve is required. In addition, the
reliability of electrically operated valves is less than
mechanically operated valves and any failure of -the valve
will cause either malfunction of the dishwasher or defeat
of the flood control feature.
Accordingly, it is an object of the present
invention to provide a flood control arrangement for
washing machines in which 24-hour flood control protection
is afforded.
It is a further object o the present invention to
provide such a flood control feature which operates in a
highly reliable manner, but does not substantially add to
the cost of manufac-ture of the machine.
SU~RY OF THE INVENTION
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These and other objects of the present invention,
which will become apparent upon a reading of khe followlng
s~ecification and claims, are accomplished by the provision
of a flood control valve comprised of a movable sealing
plunger disposed in a plunger housing having internal
openings establishing fluid communication through the valve.
The sealing plunger is proviaed with a sealing
head having a sealing surface and is adapted to be urged
into a sealing engagement wi-th a valve seat surface in the
plunger housing by water line pressure to prevent flow into
the dishwasher. The sealing engagement of the sealing plunger
is blocked except when flood conditions exist in the
dishwasher tub by means of a float disposed in the dishwasher
tub having a stem portion engaging a stem portion of the
9D~DW-~3565
plunger seal such as to preclwde sealing engagement of
the head portion.
In one version, this is accomplished by the float
stem moving into an aligned position with the end o~ the
plunger seal stem preventing it from being moved against
the valve seat~
In the second version, the float stem engages the
side of the sealing plunger stem causing it to be tilted
and misaligned with the valve seat. If a flood condition
occurs, the floal rises sufficiently to release the float
stem from blocking engagement with the sealing plunger
allowing line water pr ssure to move the plunger seal into
sealing engagement and discontinue further in-flow to the
dishwasher.
DESC~IPrrION O~ T~IE DRAWINGS
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FIGURE 1 iS a fragmentary view of a dishwasher in
front elevation shown in partial section to depict the rela-
tionship of the components of the present invention to the
d:lshwasher s-truc-ture.
FIGURE 2 iS a view in partial sec-tion of the major
components of the flood control arrangement according to the
present invention as shown in FIGURE 1.
FIGURES 3 and 4 are sectional views of the sealing
plunger and associated plunger housing, depicting the
alternate versions of the present invention.
DETAIL:E~D DESCRIPTION
In the following detailed description, certain
specific terminology is employed for the sake of -the
clarity in the description of particular embodiments
of the presen-t invention, b~t it is to be understood that
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9D-DW-13565
the same is not intended to be limiting and should not be
so construed inasmuch as the invention is capable of ta~ing
many ~orms and variations within ~he sco~e of the appended
claims.
S Referring to the drawings and particularly FIGUR~ 1
a c~nv~ntional dishwasher 10 is depicted into which is i~oo~-
pora~ed the flood control arrangement accordin~ to the pre-
sent invention. The dishwasher illustrated is of the bu$1~-
in cabinet style, installed between adjacent kitchen ca~inetry
- lQ 1~. ~he dishwasher 10 includes an inner framq 14 ~o whi~h is
mounted the outer cabinet panel 16 which provides access to
the operating components, and front mounted access door 18
providss access to the interior 20 of the dishwasher.
In th~ dishwasher interior 20 are mounted one or
more racks 22 adapted to receive the dishware items to be
washed. Such racks 22 are mounted on rollers 24 ~or in and
aut movement for convenienb loading of the dishware items.
The lower region of the interior 20 is cornprised
of a tub 26 which acts to collect the water introduced into
the machine and directed in a high pressure spray at the dish~
ware items. The washing action is carried out by me~ns o~
a rotary spray ann 28 into which is circula~ed water under
high pressure in order to wash and rinse the dishware items
disposed in racks 22.
The water collected in tub 26 is direct~d through
an inlet fitting 30 to the inlet side of a pump 32, driven
by an electric motor 34.
The outlet 36 of pump 32 ao~unicates w~th interT
nal flow passages to provide the high pressure circulation
to the rotary spray arm 28 during the wa$h and rinse cycles~
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9D-DW 13555
After the wash and rinse cycles, the water in the
tub 26 is pumped via drain outlet 38 to a plumbing drain.
In order to provide the proper volume o water
necessary for the wash and rinse cycles, an automatic ~
arrangement is provided or introducing the water from the
hot water connection in-to the machine~ This arrangement
conventionally includes a hot water pipe shown partially at
40 in communication with the hot water supply. The hot water
pipe 40 is in fluid communication with a fill valve assembly
42 which is solenoid operated to establish a timed interval
of communication at the appropriate points in the machine
cycle with a fill hose 44, which extends upwardly along the
dishwasher cabinetry and is placed in communication with a
fill nozzle fitting 46 which directs the hot water into the
interior of the machine during the fill cycle.
The flood control arrangement, according to the
present invention, acts to mechanically p.reven-t ~ater flow
from the fill valve assembly 42 into the tub 26 wherlev~r
flood conditions within the tl.ib 26 are approached.
2~ The ~lood control arrancJement as sean in FIGURE 2
consists of the combination of a flood control valve 48 and
a float assembly 50. The flood control valve 48 is in fluid
communication with the fill hose 44 and the fill valve assem
bly 42. A short length of hose 52 joins the outlat fitting
54 of the fill valve assembly 42 and an inle~ fitting 56 of
the flood control valve 48. The outlet of the flood control
valve 48 is secured to the fill hose 44 to thus be placed in
fluid communication with the fill circuit downstream of the
fill valve assembly 42.
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9D-DW 13565
The flood contxol val~e 48 consists of a plunger
housing 60 within which is movably mounted a qealing plunger
62. The plunger housing 60 is fo~ned with a relatively large
diameter inlet chamber 64 which receives a sealing head 66 por~
tion of the sealing plung~r 6~. A stem 68 of the ~ealing
plunger 62 extends into an elongated passage 7Q in communica-
tion with the inlet chamber 64 and of a larger diameter than
the stem 68 to allow water flow between the stem 68 and the
passage 70. Sealing head 66 is maintained in position in the
inlet chamber 64 with a plurality of circumferentially spaced
webs 72 which allow flow around the sealing head 66 and into
the passage 70 with the sealing plunger 62 held in position as
shown in FIGURE 2.
The effective inlet water pressure received from
the fill valve assembly 42 acts on the sealing head 66 an.d
urges the sealiny plunyer 62 to the right as viewed in FI~URE
2. A valve seatiny surEace 74 i9 provided on the oppoCi.te
face of the sealing head 66 ~rom the directi.on oE water pres-
~ure and is adapted to eng~c3e an annular sur~ace 76 ormed on
~0 ~he end wall o~ the inlet chamber 64, such that upon movement
into engagement therewith~ shutoff oE the water ~low down~
stream of the flood control valve 48 is provided.
The sealing plunger 62 is maintained in its unseated
position shown in FIGU~E 2 by blocking means including a ~loat
stem member 78 having its end portion posi~ioned in abutment
with the end face 80 of the stem 68. The float s-tem member
78 moves with a float 82 positioned in the bottom of tub 26,
with -the float stem member 78 pa.ssing thxough the interior
opening 84 of a float guide 86. Float guide 86 extends upward~
ly over the flood level indi.cated at line 88 such that water
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9D DW-13565
will not flow throuyh the interior opening 84 through which
the float stem member 78 enters.
A seal 79 is provided in the plunger housing 60
which prevents the water from passing out between the float
stem member 78 and the plunger housing 60.
Surrounding the float 82 i5 a protective float
, housing 90 with inlet cutouts 92 provided to enable the water
to pass into the interior of the float housing 90. Float 82
is pro~ided with an annular bell chamber 94 with an inner
opening 96 provided adjacent the float guide 86 to enable
venting of the air and allowing the water level to thereby
rise to the interior 98 of the float housing 90.
The float guide 86 also insures guiding movement of
the float to prevent tipping movement.
The relative weight and buoyancy of the float 82 is
such that it will not rise in the housing appreciably until
the flood level indicated at line 88 i5 approached. At this
point, the buoyancy ~orce moves the 10at 82 vertically upward-~
ly with the 10at sten~ member 78 moving out of blocking enc3age-
ment with the end face 80 of the stem 68. ~rhe water pressure
thus acts on the sealing head 66 to force the sa~e into sealing
engagement with the valve seating .surace 76 to shut off fur
ther water in-flow to the dishwasher.
The buoyant force is increased by the annular bell
chamber 94 and also may be contributed to by buoyancy of the
material i-tself by employing a molded plas~ic material of a
specific gravity less than 1.
Accordingly, after the water level in the tub 26
approaches the flood le~el indicated at line 88, the float 82
rises vertically freeing the end of the stem 68 which is thus
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9D-DW~13565
forced against the annular surface 76, discontinuiny further
in-flow to the fill hose 44 and the tub 260
Accordingly, it can be seen that an entirely mechani~
cally operated flood control arrangement is provided which does
not require operation of the electrical controls of the dish-
washer to thus provide 24-houx pxotection. The mode of opera-
tion with the water pressure ~reates the valve sealing action
acting with a high degree of reliability to prevent flood con-
ditions arising from any cause, either electrical or mechanical
of the fill ~alve assembly 42, or of some other condition~ such
as a clogged drain.
Once an overfill condition has occurred, the refilling
of the ~ub is precluded by mov2ment of the stern 68 beneath -the
float stem member 78, such that the owner or operator of the
machine is apprised of the fact -that th~xe has be~n a s~skem
malf~mction crea~ing the flood condi.tic)n. The machine will
therefore be cau~ed to rece:ive proper mai.ntenance attention
prior to another use of the dlshwasher. The stem 68 is eas:ily
repo~itioned by :remo~al of the hoses 52 and 4~, after i.nsurillg
that -the Eill valve has funct.ioned to close and repositioning
of the seali.ng plunyer 62 has occurred ~FIGURE 23.
FIGURE 3 depicts an alternate mounting arranyement
for the sealing plunger 62 in which a spring 100 is employed
to make the repositioning operation simpler, i.e., upon re- ~
lief of pressure in the inlet chamber 6~, the spring lao will
reposition the sealing plunger 62 in the appropriate unsealed
position enabling ~he valve stem member 78 to be repositioned
behind the end face 80.
FIGURE 4 depicts an ~lternate embodiment in which
the valv:Lng action is controlled by a side engagement of the
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float stem member 78 with the stem 68. The valve stem member
78 causes the sealing plunyer 62 ~o be tilted, thus precluding
the sealing engagement of the valve seating sur~ace 74 with the
annular surface 76 until such time as the ~loat rises upon the
creation of a near flood condition in the tub 26.
These embodiments of~er the same advantages as the
preferred embodiment described in FIGURE 2. It can be seen
that this design achieves the above-recited objects of the
invention producing a relatively simplified but reliable and
mechanical flood control arrangement which offers 24 hour pro-
tection against flooding and which may be incorporated at rela-
tively low cost.
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