Abstrict A flow meter and electrically operable valve assembly having an
integral flow meter provide detection of very low water flows along
with ease of installation and compact packaging for a water supply
control system. The flow is particularly useful for systems that
control household water supplies to prevent flooding, but is also
useful in other applications such as agricultural and industrial
systems where low water flow rates must be determined. All of the
controls and features are integrable within a compact package that
occupies essentially the same volume and piping space as a conventional
electrically operable valve.
Claims What is claimed is:
1. A flow meter integrated within a water system control device
including a flow resisting element and a bypass channel around said
flow resisting element said flow meter comprising: a movable indicator
disposed within said bypass channel; and a detector for detecting
a position of said movable indicator, whereby a flow through said
water system control device may be determined.
2. The flow meter of claim 1 further comprising a second flow
resisting element contacting said moveable indicator when said flow
occurs, whereby displacement of said flow resisting element is proportional
to a force produced by flow through said bypass channel.
3. The flow meter of claim 2 wherein said second flow resisting
element is a spring disposed within said bypass channel.
4. The flow meter of claim 1 wherein said movable indicator comprises
a ball within said bypass channel, and wherein said bypass channel
defines a chamber having a diameter larger than a diameter of said
ball wherein said ball may move.
5. The flow meter of claim 4 wherein said ball is made of a material
having magnetic properties and wherein said detector is a hall effect
sensor mounted within said housing.
6. The flow meter of claim 4 wherein said bypass channel includes
an inlet having a diameter smaller than said diameter of said ball
whereby said ball may seat against said inlet, blocking a reverse
flow through said bypass channel from said household water supply
outlet to said water supply inlet.
7. The flow meter of claim 1 wherein said detector is a detector
for detecting the proximity of a material having magnetic properties,
and wherein said movable indicator is made from a material having
magnetic properties.
8. The flow meter of claim 1 wherein said water system control
device is an electrically operable valve assembly including an electrically
operable valve comprising a flow resisting element disposed between
a water supply inlet and a household water supply outlet and a bypass
channel leading from said water supply inlet to said household water
supply outlet, and wherein said movable indicator is disposed within
said bypass channel.
9. The flow meter of claim 1 wherein said water system control
device is an electrically operable valve assembly including an electrically
operable valve comprising a flow resisting element disposed between
an internal chamber and a household water supply outlet and a bypass
channel leading from said internal chamber to said household water
supply outlet, and wherein said movable indicator is disposed within
said bypass channel.
10. The flow meter of claim 1 wherein said water system control
device is a backflow preventor.
11. The flow meter of claim 1 wherein said detector is an analog
detector determining a continuous position of said movable indicator.
12. The flow meter of claim 1 wherein said detector is a binary
detector determining that a position of said moveable indicator
has exceeded a predetermined position.
13. A flow meter integrated within a water system control device
including a flow resisting element and a bypass channel around said
flow resisting element said flow meter comprising means for detecting
a flow through said bypass channel.
14. The flow meter of claim 13 wherein said flow meter further
comprises means for detecting a displacement of said flow resisting
element.
15. A backflow preventor including a flow meter, comprising: a
flow resisting element for resisting a backflow through said backflow
preventor; a movable indicator mechanically coupled to said flow
resisting element; and a detector for detecting a position of said
movable indicator, whereby a flow through said water system control
device may be determined.
16. The backflow preventor of claim 15 wherein said detector detects
a position of said movable indicator when forward flow occurs through
said backflow preventor.
17. The backflow preventor of claim 15 further comprising: a bypass
channel for conducting a flow of water around said flow resisting
element; a second movable indicator disposed within said bypass
channel; and a second detector for detecting a position of said
second movable indicator, whereby a flow through said water system
control device may be determined.
18. The backflow preventor of claim 16 wherein said detector provides
a high flow indication and said second detector provides a low flow
indication.
19. A backflow preventor comprising: means for resisting a backflow
of water through said backflow preventor; and means for detecting
a position of said resisting means for providing an indication of
forward flow through said backflow preventor.
20. The backflow preventor of claim 19 further comprising second
detecting means for providing an indication of forward flow through
a bypass channel of said backflow preventor.
Description BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to liquid flow meters,
and more specifically, to a positive flow meter for incorporation
within an electrically operable valve assembly for controlling a
water supply.
[0004] 2. Background of the Invention
[0005] Water supply control systems for household use generally
require a measure of water flow, so that water leaks may be detected.
Typical flow meters use a paddle or other device inserted into the
liquid flow. Displacement of the paddle against a restoring force
provides a linear or angular measurement of the flow amount. However,
paddle type flow meters generally cannot measure the low flow rates
associated with slow water leaks.
[0006] A water supply control system also generally requires an
electrically operable valve to control water flow and other devices
such as a pressure regulator and backflow preventor. The combination
of all of these devices along with a flow meter makes a very large
in-line installation in a typical water supply control system and
requires a number of connections, each that may be susceptible to
failure. Assembly time is also increased when the devices used are
discretely installed in-line.
[0007] Therefore, it would be desirable to provide a flow meter
for measuring low flow rates associated with small leaks. It would
further be desirable to provide a flow meter that may be integrated
with other devices such as electrically controllable valves, backflow
preventors and pressure regulators, whereby fewer interconnects,
smaller in-line installation space and less assembly time is required.
SUMMARY OF THE INVENTION
[0008] The above objective of providing a flow meter for measuring
low flow rates that does not require additional in-line space, additional
interconnects and assembly time is achieved in a positive flow meter
that may be constructed integral to an electrically controllable
valve, pressure regulator and backflow preventor. The water system
control device and flow meter are thus incorporated within one housing.
[0009] The positive flow meter is integrated in a water control
system valve or backflow preventor that include a main chamber and
a bypass channel. A movable indicator is disposed within the bypass
channel and a position sensor is located near the bypass channel
so that the position of the movable indicator is detectable via
the sensor. The flow meter may further be integrated with a backflow
preventor having a flow resisting element and a position sensor
located near the flow resisting element so that a position of the
flow resisting element may be detected to provide a measure of flow
in the forward direction. A combination of sensors may be used on
the flow resisting element and the bypass channel indicator to provide
a high flow/low flow indication.
[0010] The foregoing and other objectives, features, and advantages
of the invention will be apparent from the following, more particular,
description of the preferred embodiment of the invention, as illustrated
in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a mechanical drawing depicting a cross-section
of an electrically operable valve assembly incorporating a flow
meter in accordance with an embodiment of the invention.
[0012] FIG. 2 is a mechanical drawing depicting a top view of the
electrically operable valve assembly of FIG. 1.
[0013] FIG. 3 is a mechanical drawing depicting a cross-section
of an electrically operable valve assembly incorporating a flow
meter in accordance with an alternative embodiment of the invention.
[0014] FIG. 4 is a mechanical drawing depicting a cross-section
of a backflow preventer incorporating a flow meter in accordance
with an alternative embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] 1. Electrically Operable Valve
[0016] Referring now to the figures and in particular to FIG. 1
an electrically operable valve assembly 10 in accordance with an
embodiment of the present invention is depicted. A water supply
inlet 11 provides a connection to a water supply system such as
a city water main connection. A household water supply outlet 12
provides connection to a household water supply system. In the depicted
embodiment, electrically operable valve assembly 10 includes a backflow
preventor, which prevents any backflow of water to the water supply.
The backflow preventor comprises a piston 30 and spring 31 that
prevent the flow of water when back water pressure moves piston
30 to compress spring 31. Alternatively a ball 30A may be used in
place of piston 30 with the ball mounted above spring 31. Alternatively,
as shown in balloon 40 a ball 30B may be used in place of piston
30 with the ball mounted above a spring 31A. The backflow preventor
device is closely coupled to the operation of an integral flow meter,
which will be described in further detail below. The backflow preventor
device is closely coupled to the operation of an integral flow meter,
which will be described in further detail below.
[0017] Control of electrically operable valve assembly 10 is provided
by a piston-mounted gasket assembly 20 that shuts off the main water
channel from water supply inlet 11 to household water supply outlet
12. Gasket assembly 20 is slidably mounted on an outer piston 23
that surrounds an inner piston 22. Outer piston 23 is mechanically
coupled to a lower diaphram 16. Electrically operable valve assembly
is closed by water pressure on the lower side of lower diaphram
16 causing outer piston 23 to move gasket assembly 20 to force the
gasket against seat 21. The water pressure on the lower side of
lower diaphram 16 is supplied by a channel 15 that receives flow
when a piston 14 coupled to electrical solenoid 13 is in the raised
position. Referring momentarily to FIG. 2 channel 15 receives flow
from central aperture 51 which in turn receives flow from peripheral
aperture 55 when piston 14 is raised (an o-ring or washer is provided
at the end of piston 14 to provide a seal). Peripheral aperture
55 is coupled to water supply inlet 11 and thus provides a source
of pressure higher than household water supply outlet 12.
[0018] Since the only path to the lower side of lower diaphram
16 is provided through channel 15 when piston 14 is lowered, water
pressure must be relieved through channel 15 to open electrically
operable valve 10. Piston 14 is hollow, and provides a connection
from channel 15 (via central aperture 51 of FIG. 2) to a side port
channel 24 that extends around the diaphram assemblies and connects
to an exit channel 26 on the outlet side 12 of electrically operable
valve 10. Referring to FIG. 2 the path of channel 24 connects through
channels 54 and 56 to channel 17 and venturi 18 of FIG. 1. Flow
in the main channel of electrically operable valve 10 causes a reduced
pressure at venturi 18 pulling water through the above-described
path from the top side of lower diaphram 16 as the valve closes.
A stop ball 53 disposed within channel 54 prevents backflow through
this path.
[0019] Solenoid 13 may be a latching-type solenoid, permitting
a momentary pulse to operate electrically operable valve assembly
10. A latching solenoid is preferred for extending solenoid life
and for reducing power consumption and noise, but a standard solenoid
may be preferred if it is desirable to cut-off water flow when electrical
supply to the assembly fails.
[0020] 2. Pressure Regulator
[0021] Upper diaphram 25 provides a pressure regulator integrated
within electrically operable valve assembly 10. A channel 17 connects
to a venturi 18 that couples the household water outlet side 12
of electrically operable valve assembly 10 to the lower side of
upper diaphram 25. The pressure supplied through channel 17 to upper
diaphram 25 acts against spring 27 that is manually adjustable via
turnscrew 28. When the outlet pressure exceeds a level as set by
turnscrew 28 adjustment, upper diaphram 25 lifts inner piston 22
raising gasket assembly 20 restricting the flow through the main
channel of electrically operable valve assembly 10. Thus, a pressure
feedback mechanism is established that regulates the pressure at
outlet 12.
[0022] 3. Flow Meter
[0023] A flow meter may be implemented within electrically operable
valve assembly 10 by a sensor 35 mounted near bypass channel 32
inlet. A ball 34 is mounted within bypass channel 32 and may be
made of a magnetized material or ferromagnetic material for use
with a hall effect sensor. Sensor 35 may be a hall effect sensor,
inductive sensor or other suitable sensor for detecting the proximity
of ball 34. The output indication from sensor 35 may be a continuous
analog reading of the position of ball 34 or a binary flow/no-flow
indication.
[0024] The flow meter implemented by ball 34 and sensor 35 is a
positive flow meter in that any flow through valve assembly 10 will
move ball 34 away from sensor 35 providing measurement of flows
much lower than flow rates detectable with conventional flow meters
for household water supply applications, which typically cannot
detect flows below 0.5 gallons per minute. The positive flow meter
permits detection of low volume water leaks that may cause damage
to a structure without registering a flow at a flow meter detection
system. Since any flow through valve assembly 10 requires a pressure
drop between water supply inlet 11 and household water supply outlet
12 ball 34 will move away from sensor 35 as flow through bypass
channel 32. Spring 33 has a very low spring constant and very little
force on ball 34 is required to compress spring 33. When no flow
(or back flow begins to occur), ball 34 will be forced by spring
33 against seat 36 effectively closing bypass channel 32 to prevent
backflow leakage. Setscrew 37 permits adjustment of the cross-section
of bypass channel 32 providing a means for adjusting the sensitivity
of the flow meter at the factory or after installation. As the channel
cross-section decreases, the amount of force compressing spring
33 for a given flow rate will increase, thus increasing the sensitivity
of the flow meter.
[0025] Spring 31 is designed so that gasket assembly 30 will not
open the main valve channel until the sensor 35 detects positive
flow and therefore any flow through electrically operable valve
assembly 10 will result in an indication from sensor 35. The above
operation is accomplished by making the spring constant of spring
31 such that ball 34 will travel past sensor 35 before spring 31
is compressed to open the main valve channel.
[0026] 4. Alternative Electrically Operable Valve and Flow Meter
1
[0027] Referring now to FIG. 3 an electrically operable valve
and flow meter in accordance with an alternative embodiment of the
invention is depicted. In this embodiment, the pressure regulator
is removed from the embodiment depicted in FIGS. 1 and 2 simplifying
the structure of the assembly. In the depiction, like reference
numbers are used to indicate the corresponding components, the operation
of which is described above for the embodiment of FIGS. 1 and 2.
Therefore, only differences between the assemblies will be described.
[0028] Piston 23A is a single sleeve piston operating in similar
fashion to outer piston 23 of FIG. 1. Piston 23A does not have to
be hollow, as inner piston 22 of FIG. 1 was provided to implement
pressure regulation and is therefore not needed in the present embodiment.
Piston 23A is slidably coupled to gasket assembly 30A, which is
operated by diaphram 16 or backpressure from water supply outlet
12 eliminating the need for the separate gasket assemblies 30 and
20 of FIG. 1. The sliding mount of gasket assembly 30A in conjunction
with spring 31 provides closure of the main channel at the onset
of flow until ball 34 has seated against seat 36 providing proper
operation of the flow meter within the bypass channel. However,
since forward pressure can be applied through channel 32 when the
valve is closed (channel 32 in the embodiment of FIG. 1 is effectively
closed by gasket assembly 20 when the valve is closed), a second
seat 36B is provided for ball 34 in the reverse flow direction,
preventing leakage through the flow meter channel 32 when the valve
is closed. The bottom of seat 36B is provided by a threaded insert
43 in the depicted embodiment. In order for ball 34 to move when
a forward flow is generated through the valve assembly, water must
flow channel 32. Forward flow is provided by a channel passing through
threaded insert 43. Balloon detail 42 depicts the above-described
channel 38 that is cross-drilled through threaded insert 43 to connect
with the hole that is drilled to retain spring 33. When the valve
is closed, water can flow through channel 38 from the center of
spring 33 until ball 34 seats at bottom seat 36B.
[0029] 5. Alternative Embodiment--Backflow preventor with Flow
Meter
[0030] Referring now to FIG. 4 a backflow preventor 70 in accordance
with an alternative embodiment of the invention is depicted. Backflow
preventer includes a water supply inlet 72 and a water supply outlet
71 for coupling the backflow preventer to an electrically operable
valve for control of a household water supply. a plunger 74 is slidably
mounted on a piston assembly 73 which includes vanes 72 that permit
the passage of water beyond piston assembly 73. A spring 75 pushes
plunger 74 against a seat, preventing flow of water from water supply
outlet 71 to water supply inlet 72. Flow from water supply inlet
72 to water supply outlet 71 compresses spring 75 and spring 75
can be designed to provide pressure reduction from water supply
inlet 72 to water supply outlet 71 if desirable for a particular
application.
[0031] A flow meter is integrated within backflow preventor 70
by a ball 81 and sensor 85 which operate and are constructed as
described above for the flow meter incorporated within the electrically
operable valve asembly 10 of FIG. 1. Spring 82 is compressed by
flow through channel 80 and the spring constant of spring 82 is
specified so that ball 81 will move away from sensor 85 at a flow
rate lower than that required to move plunger 74. A seat 83 prevents
backflow through channel 80 and a setscrew 84 provides adjustment
of the cross section of bypass channel 80 permitting adjustment
of the flow meter sensitivity. A second flow meter may be incorporated
within backflow preventer 70 by incorporating a movable indicator
76 on the end of plunger 74 and detecting the position of movable
indicator 76 with a second sensor 77. Since ball 81 will move at
flow rates lower than those required to move moveable indicator
76 sensor 77 is a "high flow" indicator with respect
to sensor 85 which may provide a failure indication if sensor 85
is inactive when sensor 77 provides an indication of flow. Or, sensor
85 and sensor 77 may be used within a household water control system
to provide indication of various levels of flow. For example, a
dripping faucet will activate sensor 85 but will probably not activate
sensor 77 while a major plumbing leak will activate both.
[0032] The embodiments of the invention described above disclose
an electrically operable valve with pressure regulation incorporated
within one housing and using common mechanisms between the valve
and pressure regulator. In the alternative embodiment, backflow
prevention and flow rate indication are corporated also within a
common housing. Both embodiments provide a flow meter capable of
registering very low flow rates, so that household leak detection
may be accomplished for very low flow rate leaks. The valve is suitable
for use within the system and method described in the above-incorporated
patent application "METHOD AND SYSTEM FOR CONTROLLING A HOUSEHOLD
WATER SUPPLY", wherein the valve will provide a compact solution
having very high sensitivity to water supply system leaks.
[0033] While the invention has been particularly shown and described
with reference to the preferred embodiments thereof, it will be
understood by those skilled in the art that the foregoing and other
changes in form, and details may be made therein without departing
from the spirit and scope of the invention. |