Abstrict This invention relates to the dispensing of liquids by means of
a fluid dispensing apparatus (10) having one or more of a leakage
detection means (94), a latching solenoid (84), and a fluid flow
meter (20). The invention also provides each of the leakage detection
means, the latching solenoid, then fluid flow meter, a fluid dispensing
installation, and a method of dispensing fluid. In some embodiments,
the fluid dispensing apparatus is a pre-payment water dispensing
meter.
Claims What is claimed is:
1. A liquid dispensing apparatus for dispensing a liquid, said
apparatus comprising: a flow meter having flow rate detection means;
a latching solenoid valve operative with the flow meter for metering
the liquid being dispensed; a leakage detection means for detecting
liquid leaking from the liquid dispensing apparatus, the leakage
detection means including a diaphragm located radially to a direction
of flow of liquid through the liquid dispensing apparatus, a magnet
provided on the diaphragm and displaceable by the diaphragm in sympathy
with fluctuations in pressure exerted on the diaphragm, and a detection
switch actuatable by proximity to the magnet located on the liquid
dispensing apparatus for detecting displacement of the magnet towards
the detection switch; processing means for comparing signals from
said flow rate detection means and said leakage detection means;
and control means for interrupting the flow of liquid, wherein said
control means interrupts the flow of liquid when (1) said leakage
detection means detects a flow of liquid, and (2) said flow rate
detection means does not indicate at least a minimum predetermined
flow rate.
2. A liquid dispensing apparatus as claimed in claim 1 wherein
the detection switch of the leakage detection means is a reed switch
of the type having a magnetic reed of opposite polarity to the magnet
provided on the diaphragm, the switch being actuatable by the magnetic
repulsion of the magnetic reed as the magnet provided on the diaphragm
is displaced towards it.
3. A liquid dispensing apparatus as claimed in claim 2 wherein
the diaphragm is made of a material having a shore hardness on the
Shore A hardness scale of about 60.
4. A liquid dispensing apparatus as claimed in claim 1 wherein
the material of manufacture of the diaphragm is selected to have
a hardness on the Shore A hardness scale of between 50 and 70.
5. A liquid dispensing apparatus as claimed in claim 4 wherein
the diaphragm is made from a material selected from the group consisting
of synthetic butyl rubber, natural rubber, polyethylene, nitrile
rubber, and Neoprene.TM..
6. A liquid dispensing apparatus claimed in claim 5 wherein the
diaphragm is made of nitrile rubber.
7. A liquid dispensing apparatus as claimed in claim 1 wherein
the flow meter includes: a stator mounted in the flow path and configured
to impart an angular direction of flow to liquid passing therethrough,
a rotor mounted for rotation in the flow path immediately downstream
of the stator, the rotor including a hub and a plurality of circumferentially
spaced apart radially extending arms and axially extending vanes
protruding from said arms.
8. A liquid dispensing apparatus as claimed in claim 7 wherein
the rotor is made from a material having a density similar to that
of the fluid, the flow of which is to be measured with the use of
the meter.
9. A liquid dispensing apparatus as claimed in claim 8 which includes
a magnet mounted on the rotor and a counter configured to count
magnetic pulses which correspond to the revolutions of the rotor
and hence the liquid flow rate.
10. A liquid dispensing apparatus as claimed in claim 9 wherein
the magnet and counter are in the form of a magnet and ferritic
reed switch arrangement, the magnet being mounted on the rotor and
the counter is a reed switch actuatable by the magnet provided on
the rotor is displaced towards and passes in proximity of the reed
during rotation of the rotor.
11. A liquid dispensing apparatus as claimed in claim 9 wherein
a counter balance weight to the weight of the magnet is provided
on the rotor to ensure rotational balance of the rotor.
12. A liquid dispensing apparatus as claimed in claim 7 wherein
the rotor is made from H.D.P.E.
Description This Invention relates to the dispensing of liquids. More particularly
it relates to liquid dispensing apparatus and to a liquid dispensing
installation. It also relates to a method of dispensing a liquid.
The inventor is aware of a need for fluid dispensing apparatus
which can be used for pre-paid water distribution systems, but which
will respond to fluid leakage from a system to which it is installed,
will reduce unmeasurably low flows passing being dispensed, and
operate for longer periods of time without the need for maintenance,
in particular battery replacement.
According to one aspect of the invention there is provided liquid
dispensing apparatus which includes a housing; an inlet port leading
into the housing; an outer port leading from the housing; flow path
defining means within the housing defining a flow patch connecting
the inlet and outer ports in flow communication; and valve means
intermediate the inlet and the outer port and displaceable between
an open position and a closed position to regulate the flow of liquid
through the flow path, the inlet and outlet ports being spaced apart
and parallel.
Typically the inlet and outlet ports open out of a rear surface
of the housing.
According to another aspect of the invention there is provided
liquid dispensing apparatus which includes a housing defining a
flow path, an inlet port at one end of the flow path and an outlet
port at the other end of the flow path; valve means contained within
the housing for regulating the flow of liquid through the flow path;
and a processor contained within the housing for controlling the
operation of the valve means.
The housing may be formed from three parts, each of which is moulded
of a synthetic plastics material, two of the parts together defining
the flow path.
According to another aspect of the invention there is provided
liquid dispensing apparatus which includes a housing; an inlet port
leading into the housing; an outlet port leading from the housing;
flow path defining means defining a flow path connecting the inlet
and outlet ports in flow communication; valve means intermediate
the inlet and the outlet ports and displaceable between an open
position and a closed position to regulate the flow of liquid through
the flow path; and a flow meter for measuring the volumetric flow
of liquid through the flow path, the flow meter including a rotor
mounted for rotation in the flow path and linked magnetically to
a counter.
According to yet another aspect of the invention there is provided
liquid dispensing apparatus which includes a housing; an inlet port
leading into the housing; an outlet port leading from the housing;
flow path defining means defining a flow path connecting the inlet
port and outlet port in flow communication; valve means intermediate
the inlet port and the outlet port and displaceable between an open
position and a closed position to regulate the flow of liquid through
the flow path; and a flow meter for measuring the volumetric flow
of liquid through the flow path, the flow meter including a stator
mounted in the flow path and configured to impart an angular direction
of flow to liquid passing therethrough, a rotor mounted for rotation
in the flow path immediately downstream of the stator, the rotor
including a hub and a plurality of circumferentially spaced apart
radially extending arms and axially extending vanes protruding from
the arms.
The hub may be generally frusto-conical in shape and taper away
from the stator, i.e. in the downstream direction.
The flow meter may include a magnet mounted on the rotor and a
counter configured to count magnetic pulses which correspond to
the revolutions of the rotor and hence the liquid flow rate.
According to still another aspect of the invention there is provided
a liquid dispensing apparatus which includes a housing; an inlet
port leading into the housing; an outlet port leading from the housing;
flow path defining means within the housing defining a flow path
connecting the inlet and outlet ports in flow communication; valve
means intermediate the inlet and the outlet port and displaceable
between an open position and a closed position to regulate the flow
of liquid through the flow path, a processor for controlling the
operation of the valve means; and leakage detection means designed
to detect flow below a predetermined level and linked to the processor
so that the valve means is closed should a flow below a predetermined
level be detected.
The inlet and outlet ports may be parallel and open out of a rear
surface of the housing.
The housing may include a front surface which is parallel with
the rear surface, and at least one hole extending through the housing
from the front surface to the rear surface through which a shank
of a fastener can pass, the hole being spaced from and extending
parallel to the inlet and outlet ports. Preferably, at least two
parallel spaced apart holes extend through the housing. The or each
hole may be countersunk to receive a head of the associated fastener.
The apparatus may include a tamper indicating cap or plug receivable
in each of the holes to inhibit access to the fasteners. Alternatively,
the apparatus may include a tamper indicating cap having a number
of plugs receivable in at least some of the holes to inhibit access
to the fasteners.
The liquid dispensing apparatus may include a reader configured
to read information stored on payment means in the form of an electronic
data storage device and linked to the processor thereby permitting
the apparatus to function as a pre-payment meter.
The electronic data storage device may be in the form of a chip
card, a magnetic data carrier, or the like.
The apparatus typically includes an electrical power source, e.g.
in the form of a battery. However, the electrical power source may
be an electrical supply circuit connection, a water powered electricity
generating dynamo, all the like.
The valve means may be in the form of a diaphragm valve. In particular,
the valve means may be a latching valve.
The housing may be about the size of a conventional brick so that
it is readily mountable in a wall.
According to yet another aspect of the invention there is provided
a liquid dispensing installation which includes an inlet pipe connected
to a pressurised supply of liquid; an outlet pipe; liquid dispensing
apparatus which includes a housing; an inlet port leading into the
housing; an outlet port leading from the housing; flow path defining
means defining a flow path which connects the inlet port and the
outlet port in flow communication; and valve means for regulating
the flow of liquid through the flow path, the inlet pipe and inlet
port and the outlet pipe and outlet port being provided with complementary
formations which are slidably engageable to provide a fluid tight
connection between a downstream end of the inlet pipe and the inlet
port and between an upstream end of the outlet pipe and the outlet
port.
Preferably, male formations are provided on the inlet pipe and
the outlet pipe which formations are receivable in a liquid tight
manner in the inlet port and outlet port, respectively, male/female
fashion.
Each of the male formations may have an annular seal on its outer
surface.
The inlet and outlet pipes may be embedded in or extend through
a wall, the desired spacing of the male formations, which are typically
recessed into the wall, being determined by a spacer plate through
apertures in which the male formations protrude, the housing being
retained in position by means of at least one and preferably two
fasteners which extend through holes in the housing into engagement
with the spacer plate.
A normally closed shut-off valve may be mounted in the inlet pipe,
the valve including a closure member which is urged to a closed
position, a closure member engaging formation being mounted in the
liquid dispensing apparatus such that when the male formation of
the inlet pipe is inserted into the inlet port the closure member
engaging formation engages the closure member and displaces it away
from its closed position to permit the flow of liquid from the inlet
pipe into the flow path and when the inlet pipe is removed from
the inlet port the closure member is permitted to return to its
closed position thereby cutting off the flow of liquid.
A filter may be mounted in the inlet pipe upstream of the shut-off
valve.
The liquid dispensing apparatus may include a reader for reading
information on a storage device and a processor linked to the reader
and, configured to control the operation of the valve means and
hence the dispensing of liquid. The reader may include an electrical
contact arrangement against which a storage device, including an
electrical circuit configured complementarily to the electrical
contact arrangement, may be located in electrical communication
therewith for reading, for example, a microprocessor and associated
reader.
The installation may include a remote data access point through
which access can be gained to data stored in the processor. The
access point will typically be positioned outside the wall thereby
permitting access thereto by the authorities, e.g. a water bailiff.
The apparatus will typically be liquid dispensing apparatus of
the type described above.
According to still yet another aspect of the invention there is
provided a method of dispensing a liquid making use of apparatus
which includes a flow line, valve means for regulating the flow
of liquid through the flow line, processor means for receiving data
from a pre-payment token and for regulating operation of the valve
means, which method includes the step of signalling to a person
that his credit is almost exhausted by operating the valve means
to pulse the flow of liquid being dispensed.
According to still a further aspect of the invention there is provided
a method of dispensing liquid making use of the apparatus which
includes a flow line, valve means for regulating the flow of liquid
through the flow line, processor means for receiving data from a
pre-payment token and for regulating the operation of the valve
means which method includes the steps of sensing the rate of liquid
flow and if the flow rate remains below a predetermined level for
a predetermined period of time closing the valve means to interrupt
the flow of liquid.
According to still another aspect of the invention there is provided
a liquid dispensing apparatus which includes a housing; inlet port
leading into the housing; an outlet port leading from the housing;
flow path defining means within the housing defining a flow path
connecting the inlet and outlet ports in flow communication; first
valve means intermediate the inlet and the outlet port and displaceable
between an open position and a closed position to regulate the flow
of liquid through the flow path; a processor for controlling the
operation of the first valve means; a reader configured to read
information stored on payment means in the form of an electronic
data storage device and linked to the processor thereby permitting
the apparatus to function as a meter or a pre-payment meter; and
second valve means intermediate the inlet and the outlet port and
displaceable between an open position and a closed position to regulate
the flow of liquid through the flow path, the second valve means
having an actuating handle receiving portion shaped and dimensioned
to receive a removable actuating handle.
The second valve means may be configured such that the removable
actuating handle is only removable from said receiving portion when
the valve is in the closed position, typically in a standpipe type
installation.
However, the second valve means may be configured such that the
removable actuating handle is only removable from said receiving
portion when the valve is in the open position, typically in a yard
type installation.
The second valve means have one or more parts in common with the
first valve means. Typically, the second valve means uses the same
diaphragm as the first valve means.
The second valve means removable actuating handle may include the
payment means.
Typically, the removable actuating handle may be in the form of
a bar having an actuating handle receiving portion engaging formation.
The engaging formation may be the electronic data storage device
of the payment means.
In one embodiment, the removable actuating handle is in the form
of a Dallas tag having a magnetic data carrier provided thereon,
and the actuating handle receiving portion of the second valve means
is in the form of a recess sized and dimensioned to snugly receive
said handle therein for actuation of the second valve means. In
this embodiment the housing may have a slot provided therein to
permit the insertion and withdrawal of the removable actuation handle
into and from the housing.
The liquid dispensing apparatus may include leakage detection means
designed to detect flow below a predetermined level and linked to
the processor so that the first valve means is closed should a flow
below a predetermined level be detected.
According to still a further aspect of the invention there is provided
a method of dispensing liquid making use of the apparatus which
includes a flow line, valve means for regulating the flow of liquid
through the flow line, processor means including reader means for
receiving data from a pre-payment token and for regulating the operation
of the valve means, and a pre-payment token, which method includes
the steps of: bringing said pre-payment token into data transfer
communication with the reader means; reading the pre-payment token
into the processor; and if the pre-payment token is not valid for
dispensing the fluid, operating the valve means from the processor
to prevent the fluid from being dispensed.
The last three steps of the above method may be performed in any
order or simultaneously.
By "not valid" in relation to the pre-payment means is
meant that the pre-payment means has expired, is faulty, has been
reported missing, or the like.
According to still a further aspect of the invention there is provided
a method of dispensing liquid making use of the apparatus which
includes a flow line, first valve means for regulating the flow
of liquid through the flow line, processor means including reader
means for receiving data from a pre-payment token and for regulating
the operation of the first valve means, second valve means for regulating
the flow of liquid through the flow line, and a removable second
valve actuating handle including a pre-payment token, which method
includes the steps of: bringing said removable handle into abutment
with the second valve means and data transfer communication with
the reader means; actuating the second valve means by use of said
removable handle; reading the pre-payment token into the processor;
and if the pre-payment token is valid for dispensing the fluid,
operating the first valve means from the processor to permit the
pre-paid amount of fluid to be dispensed.
The last three steps of the above method may be performed in any
order or simultaneously.
According to yet another aspect of the invention, there is a leakage
detection means for a liquid dispensing apparatus as described above,
the leakage detection means including: a diaphragm locatable radially
to a direction of flow of liquid through the liquid dispensing apparatus;
a magnet provided on the diaphragm and displaceable by the diaphragm
in sympathy with fluctuations in pressure exerted on the diaphragm;
and a detection switch actuatable by proximity to the magnet located
on the liquid dispensing apparatus for detecting displacement of
the magnet towards the detection switch.
Typically, the detection switch is a reed switch of the type having
a ferritic reed, the switch being actuatable by the ferritic reed
as the magnet provided on the diaphragm is displaced towards it.
The material of manufacture of the diaphragm is carefully selected
to be flexible such that deformation of the diaphragm, and thus
displacement of the magnet provided on the diaphragm, will occur
in response to a pressure fluctuation which is indicative of a leakage
condition.
Typically, the diaphragm is made of a polymeric material, whether
natural or synthetic, having a hardness rating of between 50 and
70 on the Shore A scale, generally about 60. The thickness of the
diaphragm may be between 0.2 mm and 1.5 mm, typically between 0.3
mm, and 1 mm thick about the zone of inflection of the diaphragm.
Materials suitable for manufacture of the diaphragm include both
synthetic and natural nitrile rubber, and Neoprene.TM..
According to yet a further aspect of the invention there is provided
a fluid flow meter, the flow meter including: a stator mounted in
the flow path and configured to impart an angular direction of flow
to liquid passing therethrough, a rotor mounted for rotation in
the flow path immediately downstream of the stator, the rotor including
a hub and a plurality of circumferentially spaced apart radially
extending arms and axially extending vanes protruding from the arms.
The invention extends to a fluid flow meter including a rotor made
of a material having substantially the same density as the fluid,
the flow of which is to be measured by the fluid flow meter.
The rotor may be made of H.D.P.E. The use of a rotor made from
a material having a similar density as the fluid, the flow of which
is to be measured by the fluid flow meter is that rotor balance
and strength problems are less likely to arise.
The rotor may be mounted with the vanes extending away from the
stator.
The hub may be generally frusto-conical in shape and taper away
from the stator, i.e. in the downstream direction.
The vanes may be shaped and dimensioned to optimise hydraulic drag.
The hub may be hollow to reduce the inertia of the rotor.
The flow meter may include a magnet mounted on the rotor and a
counter configured to count magnetic pulses which correspond to
the revolutions of the rotor and hence the liquid flow rate.
The magnet and counter may be in the form of a magnet and reed
switch arrangement, the magnet being mounted on a displaceable portion
of the rotor and the counter is a reed switch of the type having
a ferritic reed, the switch being actuatable by the ferritic reed
as the magnet provided on the rotor is displaced towards and passes
in proximity of the ferritic reed during rotation of the rotor.
A counter balance weight may be provided on the rotor to ensure
rotational balance of the rotor.
Typically, the counter balance weight is located on the hub at
a position diametrically opposed the location of the magnet.
Where the fluid flow meter is housed between two surfaces, for
example, in a box, the invention extends further to a method of
installing a rotor into the fluid flow meter to obtain the correct
axial bearing play, the method including: deflecting under a predetermined
load the surface to which one of the bearings is fitted i.e. the
top or the bottom bearing; urging the end of the rotor, and its
associated bearing, which are remote the deflected surface, into
position; and maintaining a residual deflecting load to maintain
the bearings with the correct degree of axial play.
According to a final aspect of the invention, there is provided
a latching solenoid valve arrangement for use in polluted and/or
corrosive environments, the latching solenoid valve including: a
body defining a fluid flow path therethrough between an inlet port
and an outlet port: a valve seat located in the flow path between
the inlet port and the outlet port: a housing in the form of a receptacle,
and housed inside the housing: one or more electromagnet; a displaceable
shaft made of a material capable of being drawn towards the electromagnet
when the electromagnet is energised; a corrosion inhibiting fluid
bathing the one or electromagnet and the shaft; and a resiliently
deformable diaphragm attached at one end of the shaft and configured
to seal the housing, the diaphragm being urgable by the displaceable
shaft under the action of the one or more electromagnet, to seat
sealingly against the valve seat, to inhibit flow through the flow
path between the inlet port and the outlet port, the diaphragm further
being configured to bias the shaft into the housing.
The one or more electromagnet may be arranged to provide a guide
channel or gap within which the shaft may be guided during displacement
between a first position, in which the diaphragm is urged to seat
sealingly against the valve seat, and a second position, in which
flow is permitted in the flow path between the inlet port and the
outlet port, the electromagnet being selected to maintain sufficient
residual magnetism to maintain the shaft in substantially its last
actuated position, i.e. in the vicinity of the first or the second
position, until the electromagnet is energised in the opposite direction
by means of either switching the polarity of the energising current
or by energising a second electromagnet having windings of opposite
direction to the first electromagnet. The bias of the diaphragm
on the shaft assists the electromagnet in the urging of the shaft
between the first and second positions.
The electromagnet may be in the form of a solenoid including an
iron containing core having electricity conducting wire wound around
said core.
The housing may be part of the housing of a fluid dispensing apparatus,
substantially as described above.
The shaft may be made of mild steel, or any other sufficiently
rigid, magnetically attractable material, which is economically
viable to use. The shaft may be coated with a friction reducing
composition and/or a corrosion reducing composition.
The corrosion inhibiting fluid may be water, whether ordinary mains
water or purified, distilled and/or de-ionised water, to which a
corrosion inhibiting substance, selected to be inhibit corrosion
of the shaft, the core and windings, has been added. Typically said
fluid is non-toxic to humans at the quantities found in the housing.
The diaphragm may be made of any suitable water impervious, resiliently
deformable material.
Typically, the diaphragm is made of a polymeric material, whether
natural or synthetic, having a hardness rating of between 50 and
70 on the Shore A scale, generally about 60. The thickness of the
diaphragm may be between 0.2 mm and 1.5 mm, typically between 0.3
mm and 1 mm thick about the zone of inflection of the diaphragm.
Materials suitable for manufacture of the diaphragm include both
synthetic and natural nitrile rubber, and Neoprene.TM..
In one embodiment, the diaphragm of the latching valve is made
unitary (from a single piece of material) with the diaphragm of
the leakage detection means described above.
The diaphragm of the latching valve may be used for leakage detection,
as described for the leakage detection means above, thereby removing
the need for a separate leakage detection means.
The invention will now be described, by way of example, with reference
to the accompanying diagrammatic drawings.
In the drawings,
FIG. 1 shows a three-dimensional view of a liquid dispensing apparatus
in accordance with the invention;
FIG. 2 shows a sectional view of a liquid dispensing installation
incorporating the apparatus of FIG. 1;
FIG. 3 shows an exploded sectional elevation of the installation
of FIG. 2;
FIG. 4 shows a three-dimensional exploded view of the liquid dispensing
apparatus of FIG. 1:
FIG. 5 shows a plan view of a lower part of a housing of the apparatus
of FIG. 1;
FIG. 6 shows a sectional view of a stator of the apparatus of FIG.
1;
FIG. 7 shows a three dimensional view of a rotor of the apparatus
of FIG. 1; and
FIG. 8 shows an axial sectional elevation of the rotor of FIG.
7.
In FIGS. 2 and 3 of the drawings, reference numeral 10 refers generally
to a liquid dispensing installation in accordance with the invention.
The installation 10 includes an inlet pipe 12 connected to a supply
of pressurised liquid, typically water, an outlet pipe 14 and liquid
dispensing apparatus, generally indicated by reference numeral 16
connected in flow communication with the inlet pipe 12 and outlet
pipe 14 as described in more detail herebelow.
Referring now also to FIGS. 4 and 5 of the drawings, the liquid
dispensing apparatus includes a housing, generally indicated by
reference numeral 18 an inlet port 20 leading into the housing,
an outlet port 22 leading from the housing, and flow path defining
means defining a flow path 24 (see FIG. 3) connecting the inlet
port 20 and outlet port 22 in flow communication.
As can best be seen in FIG. 4 of the drawings, the housing 18 comprises
a lower part 26 an intermediate part 28 and a top part 30 each
of which is moulded of a synthetic plastics material.
The inlet port 20 is circular cylindrical in shape and opens into
a first chamber 32 in which is mounted a stator 34.
As can best be seen in FIGS. 5 6 and 7 of the drawings, the stator
34 is configured to act as a filter. The stator 34 has a plurality
of circumferentially spaced helically extending vanes 36 extending
outwardly from the centre region of the stator 34 with the gap width
between adjacent vanes 36 being selected to inhibit the passage
of undesirable particles through the stator 34. A series of closure
member engaging formations 40 protrude from the stator 34 axially
in one direction and a rotor support formation 42 protrudes axially
from the stator 34 in the opposite direction.
The apparatus 16 includes a rotor 44 rotatably mounted in the first
chamber 32 immediately downstream of the stator 34. The rotor 44
includes a hub 46 from which a plurality of circumferentially spaced
radially extending arms 47 and from the arms 47 axially extending
vanes 48 protrude. A lower bearing pin 50 protrudes axially from
the hub 46 and is supported on the rotor support formation 42. An
upper bearing pin 52 protrudes axially from the hub 46 in a direction
opposite to the direction of the lower bearing pin 50 and is supported
in a complementary bearing 53 provided in the intermediate part
28 of the housing 18. In order to minimise balance and strength
problems, the rotor 44 is made from HDPE, which has density similar
to that of water.
In an embodiment (not shown) the hub 46 is hollow and generally
frusto-conical in shape tapering in a downstream direction, i.e.
away from the stator 34.
A magnet 54 is mounted on that surface of the hub 46 from which
the upper bearing pin 52 protrudes. Further, a counter balance weight
56 is provided in the surface of the hub 46 at a position diametrically
opposed to the opposed to the position of the magnet 54 to ensure
that the hub 46 is rotationally balanced. A sensor in the form of
a reed switch 58 is mounted on the intermediate part 28 of the housing
18 to sense the passage of the magnet 54 and thereby count the rotations
of the rotor 44. The reed switch 58 is connected to a processor
(not shown).
The outlet port 22 is circular cylindrical in shape and defines
at its inner end a valve seat 60. The outlet port 22 is connected
in flow communication with the first chamber 32 by a generally peanut-shaped
connecting chamber 62.
The apparatus 16 includes valve means, generally indicated by reference
numeral 64. The valve means 64 includes a diaphragm 66 mounted in
the connecting chamber 62 and configured to seat sealingly against
the valve seat 60. The diaphragm 66 and intermediate part 28 of
the housing 18 define between them a vent chamber 68. A vent line
70 leads from the vent chamber 68 into the outlet port 22 at a position
downstream of the valve seat 60. A bleed opening 72 which is of
substantially smaller cross-section than the vent line 70 extends
through the diaphragm 66. A pin 74 is mounted on the intermediate
part 28 in register with the bleed opening 72 so as to remove any
blockages from the bleed opening 72 as the diaphragm 66 moves as
described in more detail herebelow.
The vent line 70 comprises an upstream portion which leads into
an intermediate chamber 78 and a downstream portion 80 which leads
from the intermediate chamber 78 into the outlet port 22. The upstream
end of the downstream portion 80 of the vent line 70 defines a valve
seat 82. The diaphragm 66 extends into the intermediate chamber
78 and is displaceable by means of a solenoid 84 into a closed position
in which it seats sealingly against the valve seat 82 thereby inhibiting
flow through the vent line 70.
The solenoid 84 is sealed into the housing 18 by means of a diaphragm
66 portion 64.1 and includes a core 86 which comprises two pieces
86.1 86.2 between which is located a shaft in the form of a plastic
nail 89 which is attached to the diaphragm portion 64.1 at one end.
A magnet 87 is provided on the nail 89 and a ferritic washer 91
further down the nail 89 completes the magnetic circuit required
to operate the solenoid 84. The diaphragm portion 64.1 acts as a
spring and biases the nail 89 into its natural position in which
the diaphragm portion 64.1 is not deformed and into a position in
which the diaphragm 66 is urged into abutment with the valve seat
82.
Flow detection means, generally indicated by reference numeral
90 is provided to sense flow through the channel 70. A magnet 94
is mounted on a flow detection portion 64.2 of the diaphragm 66.
When flow takes place through the vent line 70 before valve 64 has
opened, pressure drops in the chamber 68 and lifts diaphragm portion
64.2. The magnet 94 is thus lifted towards the ferritic reed switch
93 which is activated by the proximity of said magnet 94.
In another embodiment (not shown), the flow detection means includes
a fixed magnet and a floating magnet mounted in the vent line 70
and configured so as to repel one another. Once again, a reed switch
is mounted in the intermediate part 18 adjacent to the rest position
of the floating magnet so that flow urges the floating magnet towards
the fixed magnet against the forces of magnetic repulsion thereby
activating the reed switch which in turn is connected to the processor.
From the above description, it will be appreciated hat the flow
path is defined in and between the lower part 26 and intermediate
part 28 of the housing 18 and a suitable seal 102 is provided therebetween.
The seal 102 includes all the diaphragms required for the operation
of the device 10 and is moulded from a suitable material, here nitrile
rubber, of varying thickness as required for the various stiffnesses
of the various diaphragm portions 64.1 64.2 66 and sealing portions.
The diaphragm 64.2 nitrile rubber thickness is 0.3 mm, thereby making
it sensitive to small pressure variations.
The top part 30 is mounted on the lower and intermediate parts
26 28 and defines a chamber 104 within which the processor (not
shown) and a power supply in the form of a battery (not shown) are
housed.
As can best be seen in FIG. 1 of the drawings, a tag reader 106
and an electronic display panel 107 are provided on a surface of
the top part 30. A switch (not shown) which is configured to connect
the processor to a power source can be positioned adjacent to the
tag reader 106 and can be activated by means of a magnet mounted
on a handle of a tag when the tag is positioned in abutment with
the tag reader 106 thereby connecting the processor to the power
supply.
As can best be seen in FIGS. 2 and 3 of the drawings, the inlet
pipe 12 and outlet pipe 14 extend partway through a wall 108 and
terminate in male formations 110 which are slidingly and sealingly
receivable in the inlet port 20 and outlet port 22. Each formation
110 is provided with an annular seal 112 to ensure a fluid tight
seal between the male formations 110 and the inlet and outlet ports
20 22. In order to ensure that the spacing between the male formations
110 corresponds to the spacing between the inlet and outlet ports
20 22 use is made of an apertured spacer plate 114 through which
the male formations 110 extend parallel to one another. A pair of
spaced apart screw-threaded holes 116 is provided in the plate 114
and the apparatus 116 is secured in position by means of a pair
of Allen cap screws 118 which extend through holes in the housing
into screw-threaded engagement with the holes 116. A tamper indicating
cap or plug 122 is provided over the holes through the housing so
as to inhibit access to the screws 118 and to serve as an indicator
if an attempt has been made to tamper with the screw 118.
In an embodiment not shown, a non-return valve is provided in the
inlet pipe 12. The non-return valve comprises a poppet or closure
member which is urged resiliently to its closed position by means
of a coil spring. The closure member engaging formation 40 fast
with the stator 34 is configured such that when the male formations
110 are received in the inlet and outlet ports 20 22 it abuts against
the closure member thereby displacing it away from its closed position
and permitting the flow of liquid through the inlet pipe 12. Further,
a filter 130 is mounted in a removable portion of the inlet pipe
upstream of the non-return valve, however it can be mounted anywhere
in the inlet pipe 12.
In use, in order to have water dispensed from the installation
10 a purchaser will purchase, from an authority, e.g. a municipality,
a token, e.g. in the form of a Dallas tag, encoded with a predetermined
amount of credit. When the purchaser reaches his home he inserts
the tag into the slot housing the tag reader 106 and the magnet
positioned in the handle of the tag activates the switch which energises
the processor. The processor then reads and stores in its memory
the credit contained on the tag and adds the credit to any existing
credit. In addition, the credit on the tag is cleared. The tag also
acts as an actuating handle to operate the valve manually to a closed
position for a yard meter installation, or to an open position for
a stand pipe installation. In FIG. 3 106 indicates the card reader
slot displaceably mounted on a pair of coil springs 106.1. Further,
a shaft 106.2 is connected to the card reader slot 106 such that
when the tag is inserted and the card reader slot 106 is urged downwards
against the bias of the coil springs 106.1 the shaft 106.2 presses
on a portion of diaphragm portion 64.3 to inhibit the flow of fluid
through the vent line 70 thereby preventing flow of fluid through
the flow path 24 between inlet port 20 and outlet port 22 thereby
acting as a manual secondary valve means.
When there is no flow through the outlet port 22 i.e. when a tap
downstream of the outlet port is closed the pressure acting on the
diaphragm 66 urges it against the valve seat 60. When the tap is
opened there will be an immediate pressure drop in the vent line
70 and hence in the vent chamber 68 thereby permitting the diaphragm
66 to be displaced away from the valve seat 60 and permitting water
to flows from the first chamber 32 into the outlet port 22. As the
water flows through the stator 34 it is deflected helically as it
exits the stator 34 the helical flow of the water causes the rotor
44 to rotate. It will be appreciated that the water passing through
the rotor 44 will apply an axial drag to the vanes 48 thereby tending
to lift the rotor 34 or displace it away from the inlet port 20.
A conical section 45 configured to match the rotor 44 is fitted
over the rotor 44. The conical section 45 serves to limit short
circuiting of fluid from the stator 34 directly to the chamber 62
without registering a reading on the meter or causing lateral forces
on the rotor 44.
In an embodiment not shown, the drag is offset by the taper of
the hub 46 which effectively increases the cross-sectional area
through which the water can flow thereby decreasing the velocity
and increasing the pressure of the water which tends to urge the
rotor 44 in a direction opposite to the direction of the force exerted
by the drag on the vanes 48.
As the rotor 34 rotates, the reed switch 58 senses the passage
of the magnet and the processor registers the number of rotations
of the rotor 44 and hence the rate of flow of the water which is
communicated to the processor. It is to be appreciated that the
water existing the rotor 44 will still have a swirling action and
a baffle plate (not shown) may be provided to guide the water into
the outlet port 22. When the tap downstream of the outlet port 30
is closed pressure builds up in the outlet port 22 which prevents
flow through the vent line 70. As a result pressure acting on the
diaphragm 66 causes the diaphragm 66 to be displaced into abutment
with the valve seat 60.
It will be appreciated that for all this time the core 86 of the
solenoid 84 has been in its retracted position so that the diaphragm
66 has been clear of the valve seat 82.
When there is no flow of water the processor enters a slumber mode
thereby conserving power. When the tap is once again opened there
will be flow through the vent line 70 which causes the magnet 94
to be displaced and permit the flow detection means 90 to detect
flow which will alert the processor which will then record the volume
of water dispensed by means of the rotor 44 in the manner described
above and will update the user's credit accordingly.
It will be appreciated that the inertia of the rotor 44 will be
very low and that little flow will be required in order to rotate
the rotor 44. However, it may be possible that with flow rates below
the minimum rated flow rate the rotor 44 will not rotate. In this
case, the flow detection means 90 will detect the flow in the manner
described above thereby activating the processor. If the processor
does not receive a signal from the reed switch 58 within a predetermined
period of time, e.g. three seconds, indicating the rate of flow
then the processor will operate the solenoid 84 so that the moveable
piece 86.2 of the core 86 is displaced to its protruding or extended
position (shown in FIG. 3 of the drawings) in which it urges the
diaphragm 66 against the valve seat 82 thereby preventing flow through
the vent 70. This results in a pressure build-up in the vent chamber
68 which urges the diaphragm 66 against the valve seat 60 thereby
interrupting the flow of water. It will then be necessary for a
user to reset the installation, e.g. by positioning his tag in abutment
with the tag reader 106 which will cause the processor to activate
the solenoid to retract the moveable piece 86.2 of the core 86.
Once in its retracted position the moveable piece 86.2 is retained
in its retracted position against the bias of the diaphragm portion
64.1 by residual magnetism. Naturally, should the flow detection
means 90 once again detect a flow rate below a predetermined minimum
level which is indicative of a leak or that the flow meter comprising
the rotor 44 and reed switch 58 is not operating the solenoid will
once again be energised to interrupt the flow of water in the manner
described above.
It is to be appreciated that in order to displace the piece 86.2
it is necessary only to assist the diaphragm 64.1 in overcoming
the force of the residual magnetism which requires very little electrical
energy.
Typically flow rates below the rated flow rates would be symptomatic
of a leak. Hence, by making use of the flow detection means 90 leakages
may be detected and be shut off.
As mentioned above, when there is no flow through the outlet port
and hence through the vent line 70 the diaphragm 66 is urged against
the valve seat 60. However, when there is flow through the vent
line 70 the diaphragm 66 is permitted to be displaced upwardly
away from the valve seat 60. Accordingly, instead of making use
of the magnets 92 94 the flow detection means 90 may include a
magnet (not shown) mounted on a pin 150 which is fast with the diaphragm
66 for displacement therewith. The pin rides in a complementary
recess 152 in the intermediate part 28 of the housing 18. The magnet
is mounted on that end of the pin 150 remote from the diaphragm
66.
Hence, when there is flow through the vent line 70 the diaphragm
66 is displaced upwardly away from the valve seat 60 and the magnet
mounted on the pin 150 activates the reed switch 98 which in turn
activates the processor, in the manner described above, to indicate
that there is flow through the vent line 70. If, within a predetermined
period of time, the processor does not receive a signal from the
reed switch 58 then the valve means is closed to interrupt the flow
of water and thereby restrict losses due to leakage in the manner
described above.
Further, should the user's credit which is stored on the processor
fall below a predetermined level, the processor will activate a
waning system to alert the user to the act this his credit is low.
The warning system may include a buzzer, instead, or in addition,
the processor may be configured periodically to activate the solenoid
thereby causing the valve means 64 to open and close which in turn
results in a pulsing of the water flow to provide a visual and/or
audible indicator to the user that the credit is low. This indication
is particularly valuable where the meter is located remote from
the dispensing point. The remaining credit can be displayed on the
display panel 107. Further, if the tag is held against the tag reader
for a predetermined period of time the total volume of water which
has passed through the apparatus is displayed.
If the user's credit falls below a predetermined minimum the solenoid
is operated to close the valve in the manner described above. The
valve will then remain in this position until the credit is increased
by engaging a credit containing tag in the reader 106.
The installation will typically include a remote access point 134
(FIG. 2) positioned for example on an outer surface of a wall of
a house in order that access can be gained thereto by a water bailiff
and that data stored on the processor can be downloaded simply by
pressing a sensor against the access point 134.
Should a user attempt to tamper with the installation the plugs
122 will provide a visual indication that tampering or attempted
tampering has taken place. In addition, should the user succeed
in removing the screws 118 as the apparatus 16 is removed the closure
member (not shown) will be urged to its closed position thereby
preventing the flow of water through the inlet pipe and minimising
losses in this manner.
To achieve lower power consumption, the valve means 64 is not switched
while sufficient credit remains or no leakage is detected, i.e.
it is left in the "latched open" position. Also, the processor
is only activated when flow is detected. If desired a lower power
consumption counter can be used for counting the pulses and hence
revolutions of the rotor 44. During this counting the processor
is kept in the slumber mode to conserve energy. Only when the counter
buffer is full is the processor brought into operation and the information
contained in the counter buffer is transferred to the processor.
When the battery does eventually run low a warning is placed on
the tag to inform the authorities that the battery is low and that
the apparatus 16 must be replaced. The unit is replaced by breaking
the seal 122 covering the heads of the screws 118 and removing the
screws. As mentioned above, when the apparatus 16 is removed the
closure member 126 returns to its closed position thereby shutting
off the flow of water through the inlet pipe 12.
The liquid dispensing apparatus units are factory sealed by seals
17 and must be returned to the factory to have the battery replaced
and to be recalibrated.
The centres of the seal 122 are of a thin material. This allows
the centres to be punched out when inserting an Allen key or similar
tool to unscrew the screws 118. When the screws are undone, the
remainder of the seals 122 are popped out by knocking the shank
of the screw so that the head abuts the remaining sections of the
seals 122 and dislodges them from the housing 18. Fresh seals can
then be inserted when the apparatus is re-installed.
The housing 18 is designed to be approximately the same size as
a conventional building brick which permits it to be readily mounted
in a wall.
The Inventor believes that an installation in accordance with the
invention will provide a cost effective and accurate method and
installation for monitoring the consumption of water. In addition,
by virtue of the extremely low power requirements of the installation,
the Inventor believes that a conventional battery will have an extended
life, typically of the order of five years. In addition, by virtue
of its modular "plug-in" construction, the Inventor believes
that the apparatus 16 will be relatively easy to install and replace
thereby saving time and improving productivity.
Further, the Inventor believes that by virtue of the integrated
construction of the apparatus. i.e. the fact that the housing comprises
three moulded parts which, when assembled, define the flow path,
the inlet and outlet ports and the valve seats 60 and 82 and the
fact that the meter, flow control valve, latching valve, filter,
tag reader processor, read out and battery are part of or mounted
in or on the housing, results in the apparatus being producible
at a relatively low cost. In addition, the configuration of the
flow path and the various components of the apparatus have been
designed for low flow resistance thereby to minimise hydraulic losses
which the Inventor believes will permit the apparatus to be particularly
accurate in monitoring the volume of liquid dispensed. |