Note: Descriptions are shown in the official language in which they were submitted.
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WO91/16~, PCT/AU91/00178
HYDROSTATIC DRAIN PLUG
This invention is concerned with improved
d-ain or waste plugs for liquid containing vessels.
The invention is partlcularly althougn not
exclusively concerned with drain or waste plugs
(hereinafter referred to generally as drain plugs) for
use in association with waste outlets of hand basins,
sinks, baths, spa baths, floor drains and the like in
domestic and commercial buildings, laboratories and the
like.
The simplest forms of drain plug in general
use comprise a rigid or flexible frusto-conical plug
adapted to engage in a frusto-conical neck of
complementary shape in the neck of a waste outlet or
alternatively a plug with a flexible flange adapted to
engage an annular rim of a waste outlet.
While generally effective for their purpose in
providing a msans to retain a body of liquid within a
v^ssAl Ihene plugg suffsr a numhsr of disadvantages.
Both types of plugs referred to above form a seal under
the pressure of a head of water in the vessel and as the
depth of water increases, the effort required to remove
the plug increases greatly. For children or aged or
infirm persons this can be most inconvenient and in some
cases quite dangerous.
Furthermore, if attention is distracted whilst
filling a bath, hand basin or like vessels, the vessel
may be allowed to overflow with disastrous conseauences
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to carpets, furni6hings and buildlng structures both in
domestic dwellings and multi-storey dwellings such as
hotels, apartments etc.
A significant disadvantage associated with
plugs of the above type ls that generally they are not
captive and thus are easily lost, misplaced or, in the
case of hotels and the like, stolen thereby
necessitating costly frequent replacements. Although it
is possible to make a drain plug captive by attachment
of a cord or chain this is not always convenient and can
be unsightly and difficult to clean.
There have been many attempts to overcome the
disadvantages associated with prior art drain plugs.
Exemplary of these are Australian Patent applications
12445/52 and 36335/89, Australian Patent No. 213319,
International Patent Application No. PCT/GB85/00345
(WO86/01100) and Australian Patent Application No.
66157/81.
Patsnt ,~pplic~ticn ~o. l~A45,'5~ cor.cerne a
waste outlet having a rotatable plate with apertures
selectively alignable with apertures in the body of the
outlet. The plate is rotatable to open or close the
waste outlet. This device is difficult and inconve~ient
to operate, suffers from poor liquid sealing capacity
and an exposed spring mechanism provides a lint .rap
leading ultimately to poor drainage and blockage.
Patent Application No. 36335/89 describes a
device similar to that of Patent Application No.
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12445/52 but comprises a removable plug assembly which
is easily lost or stolen.
Australian Patent No. 213319 descrlbes a
captive plug/waste outlet combination wherein sealing
engagement of the plug is achieved by rotating the plug
on a threaded shaft to raise or lower the plug relative
to the mouth of the outlet. This device suffers from
poor drainage, entrapment of lint and, in the open
position, protrudes above the surface of the outlet
_nereby causing the potential for injury in a bath or
the like.
Patent Application No. PCT/GB8S/00345
describes a waste outlet comprising a cover plate
attached to one end of a shaft and a plug attached at
the other end of the shaft. The plug i9 urged into
sealing engagement with an outlet aperture against a
spring biassing means by pushing downwardly on the cover
plate and rotating through 90 by means of a bayonet
co-upling. Th~ a particulal devlc6 ~ 5 CGn3id6~ed .0 vc
particularly prone to blockages due to entrapment of
lint in both upper and lower spring mechanisms and such
blockages would require a relatively diîficult
dismantling to clear the blockage.
Each of the above types of plug/outlet
combination are concerned with a plug which is subjected
_o hydrostatic pressure which enhances the liquid seal
and thus increases the di'ficulty of disengaging the
plug under a head of water.
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Australian Patent Application No. 66l57/8ldescribes an hydraulically actuated plug which seals
against the hydrostatic pressure of a head or water.
Apart from requiring an extremely expensive installation
S to permit selective application of mains water pressure
to actuate the plug, the system is prone to water
leakages in the pressure actuation system, blockages and
poor sealing in the presence of foreign matter.
Apart from Patent Application No. 36335/89 all
of the aforementioned prior art waste plug/outlet
combinations are subject to blockage by lint entrapment
and require either removal of the waste pipe or complete
dismantling of the plug/outlet combination for cleaning
purposes.
lS It is an aim of the present invention to
overcome or alleviate the problems of prior art waste
plug/outlet combinations and to provide a novel waste
plug/outlet with additional advantages.
~eco~-dillg ~o tne invention tnere is provided a
waste plug/outlet apparatus for liquid retaining
vessels, said apparatus including:-
a hollow body portion having an inlet port and
an outlet port, said outlet port being adapted for
connection to a liquid conduit;
a sealing means associated with said inlet
port;
a valve member movable between an open
position spaced from said sealing means and a closed
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position wherein said valve ~e~ber seali~gly engages
against said sealing member; and,
resilient biassing means to urge said valve
member towards a closed position.
Preferably said apparatus includes locking
means to selectively loc~ said valve member in an open
position.
If required said apparatus may additionally or
alternatively include locking means to Oelectively loc~
said valve member in a closed position.
The sealing means may comprise any suitable
means which, in association with said valve member,
forms a liquid tight seal ~o prevent ingress of liquid
into said inlet port.
Suitably the ~ealing means is releasably
attachable to said body portion to enable insertion to
or withdrawal from the interior of said body portion of
said valve member.
Pre,arabl-y said saalir.g m~ar.O cGmpri3aO a
sealing surface which diverges inwardly of said body
portion.
Suitably said sealing surface comprises a
frusto-conical surface adapted to engage a complementary
surface on said valve member.
Preferably said biassing means comprises a
compression spring operative between said movable valve
member and valve support member associated with said
body portion.
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If requlred said biassing means may be
adjustable to selectively vary the biassing force which
urges said valve member towards a closed position.
Suitably a cover means is associated with saia
biassing means to prevent, in use, contact between said
biassing means and foreign matter entering said inlet
port.
The valve means suitably comprises a rotatable
member having a circular head portion with a frusto-
conical sealing surface and a central valve shaft
rotatably mounted in said valve support member.
Preferably said locking means comprises one or
more projections extending perpendicularly to said valve
shaft.
The locking means suitably includes one or
more slotted reces6es a6sociated with said valve support
member to receive a respective projection to selectively
retain said valve member in an open or closed position.
Tho lock~ng maar.s m.ay alta_na.'vOlï o~
additionally comprise one or more ramped surfaces
associated with said valve support member to engage said
one or more projections to guide said valve member into
a locked open and/or a locked closed position upon
- rotation of said valve member.
Preferably grip means is provided on a
normally upper surface of said valve member to
facilitate rotation thereof.
Suitably said valve member is select1vely
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mova~le between a locked open positlon and a locked
closed position via an intermediate unlocked positi0n
wherein said valve member is urged into sealing
engagement with said sealing means by biassing force of
5 ~redetermined magnitude.
If required said biassing means may comprise a
compressible fluid or an incompressible fluid associated
with a pressure accumulation means.
In order that the invention may be more
readily understood, reference is now made to preferred
embodiments of the invention illustrated in the
accompanying drawings in which:-
FIG 1 is a cross sectional view of a drainplug~waste outlet apparatus in the closed position
FIG 2 show6 the apparatuE of FIG l in an open
position
FIG 3 shows the apparatus of FIGS l and 2 in
an exploded perspective view
FTG ~ shows a c_osz sectlor.~l view cf ~n
alternative embodiment of the invention
FIG 5 shows a cross sectional view of an
actuating means for the embodiment of FIG 4.
Referring to FIGS 1-3, the drain plug/waste
outlet comprises a body l having an externally threaded
portion 2 to facilitate connection to a waste conduit
(not shown). Removably located in the upper opening or
mouth of body l is an annular sealing member 3 which
engages an internally threaded portion 4 in the mouth of
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body ;. About the inner periphery of sealing member 3
is a frusto-conical sealing face 5 which diverges
inwardly of body 1.
Located within the hollow interior of body 1
is a valve member 6 slidably located in a valve support
member 7. Valve support member 7 comprises a central
portion 8 with an aperture 9 in which the valve member 6
is able to slide in a reciprocatory fashion. Extending
radially from central portion 8 are spaced legs 10 which
locate in recesses 11 formed on the inner wall of body
1 . ,
Valve member 6 comprises a circular cap 12
with a recess 13 in its upper surface. Within reces~ 13
is a finger grip portion 14 to facilitate rotation of
valve member 6. About the periphery of cap 12 is
located resilient seal 15 having a frusto-conical
sealing surface 16 complemen~ary to sealing surface 5 on
sealing member 3. Depending from the lower side of cap
;2 i3 a c-yllrldL~cal aha~. ;7 whicl-l slidabi-y loc~tes irl
aperture 9 in valve support member 7. Also depending
from the lower side of cap 12 is a circular wall 18
which in conjunction with hollow cylindrical shroud 19,
forms a substantially sealed enclosure 20 housing a
compression coil spring 21.
Shroud 19 had a central aperture 22 through
which shaft 17 is able to slide. A cyl~ndrical pin 23
is inserted through an aperture in shaft 17 via opposed
apertures 24 in shroud 19.
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Located within shroud l9 and between pin 23
and the central portion 8 of valve support member 7 is
an annular ~oss 25 with opposed ~bayonet~ slots 26
(shown in FIG 3)
; FIG l shows the drain plug/wa6te outlet
apparatus in a closed position whilst FIG 2 shows the
apparatus in an open position.
The operation of the apparatus according to
the invention will now be described with reference to
FIGS 1-3
The drain plug/waste outlet illustrated in
FIGS 1-3 is readily fitted to sinks, hand ba6ins, baths,
showers, spa baths and like in a conventional manner.
As shown in FIG 3, cap 12 i8 rotable between an "open"
lS position through an intermediate afill" position to a
"closed" position.
In the closed position shown in FIG l, pin 23
rests upon the upper surface 26 of boss 25 and urges the
res.lic--t scal 15 into sealir.g engasOu-.ant wit.. scal ,.g
face 5 of sealing member 3 to prevent egres6 of water or
the like through the waste outlet body l.
By rotating the cap 12 to the intermediate
~fill~ position, pin 23 is aligned with the upright
portion of slots 26 whereby the valve member 6 may be
pushed downwardly against the restoring force of spring
2l. By selecting a spring 2l having a predetermined
restoring force sufficient to sùpport a given head of
fluid pressure, the apparatus provides a very convenient
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overflow prevention means for liquid container such as
laundry t~bs, hand basins, baths etc. When the liquid
depth reaches a predetermined "safe" level, the pressure
of the head of liquid above valve member 6 begins to
exceed the restoring force of spring 21 and thus allows
excess fluid to escape via the hollow interior of body
1. The apparatus according to the invention may be
provlded with a plurallty of "standzrd" springs 21, each
having a restoring force equivalent to a predetermined
liquid depth in, say, a hand basin, a laundry tub and a
bath. Alternatively spring compre6sion means (not
shown) in the form of removable spacer or a threaded
collar on shaft 17 may be provided to selectively vary
the head of liguid able to be supported by the apparatus --
in the "fill" posltion.
To empty the li~uid container to which the
apparatus i8 fitted, cap 12 is pushed downwardly again~t .
the restoring force of spring 21 and then rotated to
r~ablE 'ha .~G Gr.d~ c, p,r. 23 ~o O~a5a ... .ha
laterally extending portion of slots 26 in boss 25
thereby retaining the valve member 6 in an open
position.
While it will be readily apparent to a skilled
addressee that the apparatus according to the invention
is readily assembled and disassembled for manufacture,
installation and maintenance purposes, there are other
significant advantages.
The configuration of the plug/outlet assembly
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permits a more rapid evacuation of liquid due to lack of
restrictions in the flow path and also due to the ready
formation of a "whirlpool~ effect at the mouth of the
r outlet.
Furthermore, the shrouding of internal
components which otherwise entrap lint, hair and other
foreign matter reduces costly mai~tenance due to
blockages and wear on movable components. In the event
that maintenance is required the entire valve assembly
is accessible and removable by removing sealing member 3
without the necessity for disconnecting the waste
conduit attached to the apparatus.
FIG 4 illustrates further embodiments of the
invention.
When the drain plug/wa6te outlet is to be used
for floor drainage for, say, a shower or a parking lot
where due to various circumstances a backflow of liquid
- can occur, an optional surge float 30 may be attached to
- th~ lowO- er.d o. .he shaft 3l attac~ed tu valve ~e~er
32. The surge float 30 urges valve member 32 into
sealing engagement with sealing member 33 as the water
level in the waste conduit 34 rises. If required, the
volume of float 30 may be chosen to operate against a
predetermined head of water to control ingress of liquid
and to prevent further flooding of a floor surface.
FIGS 4 and 5 also illustrate yet another
embodiment of the invention in the form of a remote
opening or closing device. In FIG 4 the valve support
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member 34 has an integrally formed ~oss 35 in the form
of a cylindrical body which slidingly supports the shaft
36 of valve member 32. Resilient "0" ring seals 37, 38
form fluid tight seals respectively between the shaft 36
and inner wall of boss 35 on the one hand and the outer
wall of boss 35 and shroud 39 depending from valve
member 32 on the other hand. Within the wall of boss 35
is a fluid conduit 40 which is in fluid communication
with a conduit 4l via an aperture 42 in the lower
portion of body 43.
When a source of pressurised fluid is supplied
via conduit 4l valve member 32 is driven upwardly to
seal against sealing member 33. By using a compressible
fluid such as air, the valve member 32 may be driven
into sealing e~gage~ent with sealing member with a
predetermined force which is able to be overcome by an
excess head of liquid above valve 32. Alternatively an
incompressible fluid ouch as water, oil etc may be
e~.ployed ir. conjunctior. wlth a di~ph-~. p-200'~-e
accumulator or the like to provide a similar sealing
force of predetermined magnitude.
FIG 5 shows a convenient form of remote
control of the apparatus of FIG 4.
The pressurising device comprises a piston 40
and a cylinder 4l with a non return valve 42 which may
be fitted behind a wall cladding material 43 otherwise
recessed into a wall structure. Piston 40 comprises a
large pushing cap 44 and a return spring 45. Cylinder
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4l communicates with a chamber 46 via non return valve
42 and chamber 42 is adapted to connect to conduit 4l.
Connected to chamber 46 is a needle and jet
assembly 47 to selectively allow pressurised air to be
bled from chamber 46 and conduit 4l. The needle and jet
assembly 47 is biassed into sealing engagement by a
spring 48 the tension of which spring may be adjusted by
rotation of the shaft 49 of the needle and jet assembly.
The drain plug/waste outlet apparatus of FIG 4
may be closed by a single push of cap 44 to close the
valve member 32 with a predetermined hydrostatic relief
pressure determined by the biassing force of spring 48
in the needle/jet assembly 47. Valve member 32 may be
opened simply by withdrawing shaft 49 against the
biassing force of spring 48. To assist in more rapid
opening of valve member 32, the float 30 shown in FIG 4
may be replaced with a solid mass.
As no access i8 required to the top surface of
val~v~ m2~e_ 3~ to oper. o- close the appara.us, ar.
aperture grate may be incorporated in the sealing member
33 if required.
The various embodiments of the apparatus
according to the present invention are suitable for all
domestic and commercial residential properties as well
as nursing homes, hospitals and the like. The apparatus
also has application in public facilities, floor
drainage and industrial applications.
It will be readily apparent to a skilled
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addressee that many modifications and variations may be
made to the invention without departing from the spirit
and scope thereof.
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