Note: Descriptions are shown in the official language in which they were submitted.
CA 02541613 2006-03-28
SAFETY VALVE FOR TOILET TANK
This invention relates to a hydraulically actuated safety valve which
prevents continual flow to the tank in the event of a leak from the tank.
BACKGROUND OF TME INVENTION
Standard porcelain toilet tanks may develop leaks due to improper float
arm levels, worn ball oocks, corroded flappers or worn or deteriorated tank to
bowi
gaskets. Porcelain tanks may also crack or fracture due to defects, over
tightened
tank bolts, fatigue, vibrations or temperature changes. Such a crack can
result in
flooding of the premises with consequential damage significantly greater than
the
cost of the damage to the toilet.
It is known therefore to provide devioes which time a period of flow of
water to a device and shut off the flow when the flow continues after a
required
period of time.
Such a situation may occur in the event that the tank cracks. More
commonly such an event occurs when the flapper valve leaks or sticks open.
While
the second event may not be catastrophic, if not properly monitored can lead
to
significant excess water usage.
A device of this type is particularly important in rental accommodations
where the occupants may be less attentive to the operation of and costs
associated
with the devices in the accommodations and may therefore leave a toilet tank
filling
continuously, provided it operates when required.
CA 02541613 2006-03-28
2
A number of devices have been previously provided but many of these
require a supply of electricity either from a main supply or a battery supply
to provide
actuation of etectrical components such as timers and solenoid valves. Such
devices are of course undesirable and it is much more suitable for an
arrangement
of this type to be operated solely by the hydraulic pressure and action of the
water
passing through the valve.
SUM RY OF THE INVENTION
It is one object of the invention to provide a hydraulically actuated
safety valve which prevents continual flow to the tank in the event of a leak
from the
tank by halting water flow to the filling valve in the event that the water
flow
continues for a time longer than an expected time of fiiling.
According to one aspect af the invention there is provided a safety
valve for halting water flow to a filling valve of a toilet tank in the event
of failure, the
valve comprising:
a valve body;
an Inlet connector in the valve body for inlet of water from a water
supply pipe at a supply pipe pressure;
an autfet connector in the valve body for connection to a filling line of a
toilet tank;
a water supply duct within the valve body for passage of water from the
inlet connector to the outlet connector;
a valve seat in the suppiy duct;
CA 02541613 2006-03-28
3
a valve member for movable between a closed position against the
valve seat to prevent flow of the water from the inlet connector to the outlet
connector and an open position spaced from the valve seat to allow flow;
a piston connected to the valve member for moving the valve member;
the piston being mounted in a cylinder in the valve body having a first
chamber on one side of the piston and a second chamber on the other side of
the
piston;
the piston being movable within the cylinder from a first end in which
the valve member is open to a second end in which the valve member is closed;
a venturi in the supply duct in the valve body through which the water
flows as it passes from the inlet connector to the outlet connector having an
orifice
arranged so as to provide in a low pressure chamber of the venturi a water
pressure
lower than the supply pipe pressure;
a first transfer duct in the valve body for transferring water at the
supply pipe pressure from the water supply duct to the first end of the
cylinder;
a second transfer duct in the valve body for connecting second end of
the cylinder to the low pressure chamber;
such that a pressure difference across the piston caused by the
differenoe in pressure between the supply pressure and the low pressure
chamber
causes the piston to move from the first end toward the second end;
a flow control orifice in one of-the first and second transfer ducts for
regulating a rate of flow of water therethrough such that a time of movement
of the
CA 02541613 2006-03-28
4
piston from the first end to the second end in which the valve member Is
closed is
greater than an expected time required to fili the toilet tank;
and a spring biasing the piston to the first end for returning the piston
to the first end after the toilet tank is filled, when there is no pressure
difference
across the piston;
whereby, in the event that the tank is filled and the filling valve closed
before the valve member is closed by the movement of the piston, the piston is
moved back to the first end;
and whereby, in the event the filling valve remains open for a time
longer than said time of movement, the valve member contacts the valve seat by
the
movement of the piston to prevent further supply of water to the filling
valve.
Preferably the flow Controi orifice is adjustable to vary the time of
movement.
Preferably there is provided a reset transfer duct having a reset valve
which is manually operable for transferring water under supply pressure to the
second side of the piston to reset the piston at the first end, in the event
that the
valve member is closed by the movement of the piston to prevent further supply
of
water to the filling valve.
Preferably there is provided by-pass duct with a one-way valve for by-
passing the flow control orifice to allow passage of water at a rate greater
than the
rate through the flow control orfice so as to cause the piston to return to
the first end
at a rate faster than the movement to the seoond end.
CA 02541613 2006-03-28
Preferably there is provided a low flow venturi having a second orifice
which is smaller than the orifioe of said venturi such that the low flow
venturi
provides in a low pressure chamber of the low flow venturi a water pressure
lower
than the supply pipe pressure when there is a low flow of water through the
water
5 supply duct caused by a slow leakage of the filling valve, the low pressure
chamber
of the low flow venturi being connected to the second end of the cylinder.
Preferably the low pressure chambers of the first and second venturis
are connected in series and there is a back check valve between the first
venturi and
the second venturi.
Preferably the piston has a piston rod passing through a chamber to
which the first and second venturis are attached and wherein the piston rod is
arranged to close off the connection to the first venturi before closing the
valve
member on the valve seat.
Preferably there is provided a check valve arranged to keep the first
larger venturi ciosed at low pressure until the pressure, due to the
restriction through
the low flow venturi, exceeds a predetermined value indicative of the filling
valve of
the toilet being approximately 50% to 100% open.
Preferably the flow control orifice Is in the second transfer duct.
Although it may also be located in the first transfer duct provided it
oontrols the rate
of flow of water so as to cause the piston to move only slowly to the close
position.
The valve member may be directly attached to a piston rod of the
piston and particuiariy may be located on an end of the piston rod so as to
move
CA 02541613 2006-03-28
6
axially with the piston rod onto the valve seat.
Preferably the piston rod passes through the second end of the
cylinder and the spring is mounted in the second end of the oylinder.
Preferably the venturi is downstream of the valve seat.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention wili now be described in conjunction
with the accompanying drawings in which:
Figure 1 is a schematic illustration of a safety valve for cooperation
with a filling valve of a toilet tank.
Figure 2 is a schematic illustration of a second embodiment which
utilizes a second venturi for monitoring low flow leaks,
In the drawings like characters of reference indicate corresponding
parts in the different figures.
DETAILED DESCRIPTION
In Figure 1 is shown a toilet tank 10 having a filling valve 11 operated
by a float 12, The tank has a flapper valve 13 actuated by a flush control 14.
Thus
in conventional manner when the flush control 14 is actuated, the flapper
valve is
opened allowing the water from the tank to flow into to the toilet. The
flapper valve is
intended to close after the tank is emptied and the fall of the float within
the tank as
the water is discharged opens the filling valve 11 to allow the supply of
water from a
filling line or supply pipe 15 into the filling valve to fill the tank. A
safety valve 20 is
provided which operates to halt flow of water to the filling valve in the
event that the
CA 02541613 2006-03-28
7
filling valve remains open for a period of time which is longer than that
which is
expected for the normal filling of the tank. The filling valve may remain open
in the
event that it becomes jammed or in the event that the flapper fails to close
or in the
event that the tank cracks so that the contents are discharged onto the floor
around
the toilet rather then into the toilet. In any of these events it is of course
highly
desirable that the flow to the toilet tank be halted to prevent excess usage
of water
and to prevent the possibility that the water is discharged into the premises
with
consequential significant damage.
The safety valve 20 comprises a valve housing 21. The valve housing
21 has a first connector 22 for attachment to the supply pipe. The connector
is of a
conventional nature using conventional plumbing fittings. The housing further
has a
second connector 23 for connection to a filling line 15 supplying the filling
valve.
The housing is preferably designed to be of a sufficiently small size but
it oan be located in the area of the toilet tank between the suppiy pipe and
to the
inlet at the bottom of the tank. Thus the device can be quickly and rapidly
attached
using the existing or conventional fittings which provide a filler line which
extends
generally from the floor to the boitom of the tank. In this case the supply
pipe 5 is
preferably provided at the bottom of the housing 20 and the outlet 23 is
preferably
provided at the top for connection into the bottom of the tank.
The connector 22 supplies the water from the supply pipe into a duct
26 within which is mounted a valve seat 27. A valve closure member 28 is
provided
which can be pushed axially of the duct 26 into engagement with the valve seat
27
CA 02541613 2006-03-28
8
to cause closure of the valve. Thus when the valve member 28 is moved into the
valve seat, flow through the duct 26 is halted and the supply through the
valve to the
outlet 23 is closed off thus preventing further flow of any water from the
pipe into the
tank,
The valve member 28 is mounted on the end of a piston rod 29
attached to a piston 30. The piston 30 is mounted within a cylinder 31 which
provides therefore a first side 32 of the cylinder at a first end 33. Thus
pressure
within the first side 32 is applied against one end face 34 of the piston. The
cylinder
provides a second end 35 defining a second side of the piston chamber 36. Thus
the cylinder defines two changes 32 and 36 each on a respective side of the
piston
so that the piston is moved along the cylinder in response to a differential
in
pressure between the chambers 32 and 36. A spring 37 is provided in the second
chamber 36 so as to apply additional force against the piston from the side of
the
chamber 36. A duct 38 communicates from the duct 26 through the piston rod 29
to
the first chamber 32. Thus pressure from the supply pressure at the inlet 15
is
communicated through the duct 26 and the duct 38 to the first chamber 32.
A venturi 40 is provided in a duct 41 communicating from the duct 26
downstream of the valve seat 27 to the outlet 23. The venturi 40 has a passage
42
with an orifice 43 so that at the orifice is generated an area of low
pressure. The
area of low pressure at the orifice is communicated to a low pressure chamber
45 of
the venturi. Depending on the size of the orifice 43 in the passage of the
venturi,
water will flow through the venturi at a predetermined rate for supply to the
outlet 23.
CA 02541613 2006-03-28
9
The size of the orifice is determined so that it does not signiflcantly
increase the
period of time for filling the tank. At the same time the orifice is chosen in
size so
that it generates within the chamber 45 a low pressure which is significantly
less
than the supply pressure at the inlet 15. Such a low pressure may be of the
order of
10% of the inlet pressure but can be significantly higher depending upon the
selection of the dimensions of the piston, the piston rod and the spring 37.
The low pressure chamber 45 connects through a transfer duct 46 to
the second chamber 36. Within the transfer duct 46 is provided a flow control
orifice
47 defined by a needle valve 48. The needle valve 48 is adjustable to control
the
size of the orifice 47 and thus to control the rate of flow of water through
the transfer
duct 46.
In an initial position of operation of the device with the filling valve 11
closed, the piston 30 is located at the left hand end of the cylinder facing
the
chamber 32.
in the event that the filling valve is opened, water flows past the valve
seat 27 since the valve is opened by the posihon of the piston 30 at the left
hand end
of the cylinder. Water thus flows into the duct 41 and passes to the outlet 23
to
provide filling to the tank. The water passing through the duct 41 flows
through the
venturi 40 thus providing a reduction in the pressure in the low pressure
chamber
45.
As the 1ow pressure chamber 45 is connected to the chamber 36 of the
cylinder, water can flow from the chamber 36 into the low pressure chamber 45
CA 02541613 2006-03-28
where it passes through the orifice of the venturY joining the flow through
the duct 41
and passes into the outiet 23. This flow of water from the chamber 36 of the
cylinder
aikms the pressure in the chamber 32 to cause the piston to move toward the
right.
The rate of movement of the piston is controlled by the needle valve 48 and
its
5 orifice 47. The needie valve 48 Is adjusted so that the time of movement of
the
piston before it reaches the valve seat 27 is longer than the expected time
for filling
of the tank.
In the event that the tank is filled and the filling tank 11 closed before
the valve member 28 reaches the seat 27, flow is haited through the venturi 40
by
10 the closing of the filling valve 11. In this situation the pressure in the
low pressure
chamber 45 increases back to inlet pressure so as to Increase the pressure in
the
chamber 36 of the cylinder. Thus the chambers 32 and 38 are at the same
pressure
so that the movement of the piston is controlled by the application of force
by the
spring 37.
Thus when the filling valve 11 is closed, the system moves back to the
initial position by the force from the spring 37 moving the piston 30 toward
the left.
This rate of movement can be increased by providing a valve 52 in a bypass 51
bypassing the orifice 47. In this way the flow through the transfer duct 46 to
the
chamber 36 can occur more quickly than it would if it passes through the
orifice 47
thus allowing the piston 30 to move more rapidly toward the left.
Thus it will be appreciated that the duct 38 through the piston rod
forms a first transfer duct allowing water to enter the chamber 32 and to
depart from
CA 02541613 2006-03-28
11
the chamber 32 as required. Symmetricaily the duct 46 forms a second transfer
duct
communicating with the chamber 36 of the cylinder.
In the event that a fault in the filling system means that the tank does
not fill in the expected time so that the valve 11 remains open, the piston 30
continues to move toward the right until the valve member 28 meets the valve
seat
27. In this position the water flow is closed so that no more water flows
through
either of the transfer ducts 38 or 46 and the piston 30 applies force against
the valve
seat 27.
The piston 30 holds the vaive member 28 against the valve seat 27
and the valve thus remains dosed while pressure continues to be called for at
the
Inlet 15.
A reset duct 60 is provided which communicates from the duct 26
upstream of the valve seat 27 to the chamber 36 of the cylinder. This duct 60
remains normally closed by a valve 61. However the valve 61 can be operated by
a
manual reset pull button 62. In the event therefore that the valve is closed
due to a
malfunGtion of the filling system, it remains closed until it is reopened by
manual
actuation of the reset button 62 which allows transfer of water from the inlet
to the
chamber 36 causing the piston to move toward the left. The reset button is
held for
a sufficient period of time to allow the water flow through the duct 60 into
the
chamber 36 and through the duct 38 from the chamber 32 to occur sufflciently
to
allow the piston to move to its initiai position at the left hand end of the
cylinder.
Of course it is expected that the reset button will only be depressed in
CA 02541613 2006-03-28
12
the event that the fault causing the originai failure of the filling valve 11
has been
resolved.
In the event that the tank has cracked allowing the water to discharge
from the tank, of course it will be necessary for the tank to be repiaced. In
the event
that the flapper valve has become stuck so that the tank continues to
discharge into
the toilet, return of the flapper valve to its closed position will allow the
tank to refill
after the reset button has been pressed. Repeated sticking of the flapper
valve will
of course be noted by the occupant or user of the toilet in that it will be
necessary to
repeatedly reset the valve 20 indicating that the flapper valve is continually
sticking
open.
In the embodiment shown in Figure 2 there is added a second venturi
which allows monitoring of low flow ieaks through the filler valve 11. This
may occur
due to low flow leaks past the flapper valve or due to slight overflowing of
the tank
into the overflow. The second venturi has a smaller orifice so that it allows
only a
relatively small amount of flow through the venturi while at the same time
generating
the low pressure chamber.
The arrangement as shown In Figure 2 is substantially identical to that
as shown in Figure 1 so that that the identical components are described
herein and
have the same function and arrangement as previously described. Thus in place
of
the single venturi arrangement 40 of Figure 1 there is provided two separate
venturis
70 and 71. Each of these connects to the duct 79 downstream of the inlet and
in
advance of the valve member on the end of the piston. Thus the venturi 70 is
fed by
CA 02541613 2006-03-28
13
a duct communicating from the cylindrical duct 79 at a mouth 78 and similarly
the
venture 71 is fed from a duct communicating at mouth 77. It will be noted that
the
mouth 77 is closer to the piston 30 and the valve member 28 and thus is closed
off
when the piston 30 and Its piston rod 29 move toward the right.
The venturi 70 has a smaller orifice 75 than the orifice 76 of the venturi
71. Thus the venturi 71 constitutes a high flow venturi which allows through a
higher
level of fluid while generating the neoessary low pressure within the venturi
chamber. The venturi 71 is thus intended to take the majority of the flow
since a
smaller venturi such as that venturi 70 may generate cavitation in the area
just
downstream of the venturi orifice which can rapidly cause wear within and down
stream from the safety vaive,
In order that the flow passes through the low flow venturi 70 during low
flow conditions, the larger venturi 71 has a check valve 76 which is spring
actuated
into a closed position. The valve is downstream of the venturi orifice and is
pushed
opened against the spring in the event that high flow conditions occur. The
high flow
conditions occur in the event that the filling valve 11 opens so that there is
a
significant pressure drop between the inlet 22 and outlet 23 due to the valve
11
being approx 50 to 100% opened. When this large pressure drop occurs greater
than a predetermined set value of the valve 76, flow through the venturi 71
occurs at
the high flow rate which acts to fill the tank relativeiy quickly due to the
high flow and
also avoids cavitation in the low flow venturi 70. However in the event that
the valve
11 is only slightly open due to a leak, low flow conditions occur leading to a
low
CA 02541613 2006-03-28
14
pressure drop between the inlet 22 and the outlet 23 so ftt the valve 76
remains
closed and all of the flow passes through the venturi 70. The orifice 75 of
the venturi
70 is smaller than the orifice 74 of the venturi 71. in this way the necessary
pressure drop occurs in the venturi 70 allowing the device to operate in the
same
manner as previously described so that the piston 30 moves toward the right at
a
rate of movement controlled by the valve 48. If the movement occurs over a
period
of time which is sufficient to allow the piston to reach the right hand end,
the valve
member 28 closes against a valve seat 27 thus closing off the valve as
previously
described.
Thus in low flow conditions the venturi 70 controfs the operation of the
device and allows it to close off the filling, if the low flow filling
continues over a time
period longer than an allowable time period.
During normal filling operations, the high flow rate opens the valve 76
causing the high flow to pass through the venturi 71 which then flows through
the
duct 72 into the outlet 23. When the valve member 28 passes over the port 77
the
high flow rate venturi 71 is closed off and the further filling continues only
through
the low flow venturi 70.
A back check valve 73 is provided in a duct communicating between
the chambers of the venturi 70 and 71. The back check valve 73 prevents the
water
from flowing from the chamber of the venturi 70 to the chamber of the venturi
71.
This acts to prevent low pressure in the chamber of the venturi 71 from being
filled
with water drawn from the venturi 70.
CA 02541613 2006-03-28
The piston can have an 0-ring seal or a bellows type seal, the later
having less friction then the 0-ring and allows for the miniaturization of the
device.
We will probably go this way.
The venturl can be replaced with an orifice plate; a plate with a small
5 hole placed in it. Duct 46 would intersect duct 41 just down stream of the
orifice
plate and a similar pressure drop would occur. An orifice plate may be a more
cost
effecf method of achieving the same thing.
The device could work on a hot water tank as well. The device could
be set up to close at a time just greater then say a bath filling or one
shower. With
10 hot water tank failure you always get a tank load of water on the floor.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without department from such spirlt
and
scope, it is intended that all matter contained in the accompanying
specification shall
15 be interpreted as illustrative only and not in a limiting sense.
