Abstrict A selectively energizable flow meter system comprising a valve
having at least one fluid inlet port for receiving fluid under pressure
and a plurality of fluid distribution ports and including a valve
element selectively movable to direct liquid to predetermined fluid
distribution ports, a metering device, and valve element positioning
mechanism connected to the valve element. The valve element positioning
mechanism is operable upon energization of the system to establish
fluid flow communication between the metering device and at least
one valve fluid distribution port and responsive to de-energization
of the system to direct pressurized fluid entering the valve fluid
inlet port to a valve fluid distribution port bypassing the metering
device.
Claims I claim:
1. A selectively energizable flowmeter system comprising, in combination:
valve means defining at least one fluid inlet port for receiving
fluid under pressure and a plurality of fluid distribution ports,
said valve means including a valve element selectively movable to
direct said liquid to predetermined fluid distribution ports;
metering means; and
valve element positioning means connected to said valve element
operable upon energization of said system to establish fluid flow
communication between said metering means and at least one valve
means fluid distribution port and responsive to de-energization
of said system to direct pressurized fluid entering said valve means
fluid inlet port to a valve means fluid distribution port bypassing
said metering means.
2. The system of claim 1 wherein said metering means includes a
housing having a reciprocating metering element slidably disposed
therein in fluid-tight relationship therewith, said system additionally
comprising a conduit connecting each end of said housing to said
valve means whereby pressurized fluid entering a first end of said
housing from a first valve means fluid distribution port will displace
said reciprocating metering element and cause fluid disposed between
the metering element and a second housing end to flow to a second
valve means distribution port.
3. The system of claim 2 additionally comprising means for detecting
when said metering element is at a predetermined location in said
housing, said detecting means being operatively associated with
said valve element positioning means to reposition said valve element
whereby fluid flow in said housing is reversed and pressurized fluid
from the second valve means distribution port enters the second
end of the housing to displace the reciprocating metering element
and cause fluid disposed between the metering element and the first
housing end to flow to the first valve means distribution port.
4. The system of claim 3 wherein said detecting means includes
a signal element disposed outside of said housing and fixed to said
metering element for reciprocating movement therewith and switch
means to detect the location of said signal element.
5. The system of claim 4 wherein said signal element comprises
an optical scale having indicia thereon, said system further comprising
photoelectric means for detecting said indicia and means operatively
associated with said photoelectric means and responsive to the rate
of movement of said indicia relative to said photoelectric means
for determining the rate of fluid flow through said housing.
6. The system of claim 4 wherein said valve element positioning
means includes a reversible electric motor and wherein said switch
means comprises spaced optical switches positioned adjacent to said
signal element and responsive to movement of said signal element
to a predetermined extent to actuate said reversible motor to reposition
said valve element whereby fluid flow in said housing is reversed.
7. The system of claim 6 wherein said valve element is a valve
rotor driven by the output shaft of said reversible motor, said
system further comprising means responsive to rotation of said rotor
to de-energize said reversible motor when fluid flow in said housing
is reversed.
8. The system of claim 7 wherein said means responsive to rotation
includes a disk rotatable with said rotor and an optical switch
actuated by movement of said disk relative to said optical switch.
9. The system of claim 1 wherein at least one of said fluid distribution
ports is a drain port, said valve element positioning means being
responsive to de-energization of said system to direct pressurized
fluid entering said valve means fluid inlet port to said drain port.
10. The system of claim 9 wherein said valve element is a valve
rotor and wherein said valve element positioning means includes
a reversible motor having an output shaft connected to said rotor.
11. The system of claim 10 additionally comprising means for maintaining
the reversible electric motor in an energized state upon de-energization
of said system to rotate the output shaft of said motor and said
valve rotor until said fluid inlet port is in communication with
said drain port along a flow path bypassing said metering means.
12. The system of claim 11 additionally comprising means for de-energizing
the reversible electric motor when the system is de-energized and
the valve rotor has reached the position whereat the metering means
is bypassed.
13. The system of claim 12 wherein the electric motor de-energizing
means includes an element mounted for rotation with said valve rotor
and motor output shaft and switch means responsive to the position
of said element.
14. The system of claim 13 wherein the element is a rotating disk
having a cutout formed therein and wherein said switch means is
an optical photoswitch for sensing the location of said disk cutout.
15. The system of claim 1 wherein said valve means additionally
includes a stator element defining said ports, said selectively
movable valve element comprising a rotor having channels formed
therein for selective communication of said ports through said channels
upon rotation of said rotor.
16. The system of claim 15 wherein two of said fluid distribution
ports comprise drain ports and wherein two of said fluid distribution
ports comprise metering outlet ports in direct fluid flow communication
with said metering device.
17. The system of claim 16 wherein said channels are spaced, arcuate
channels formed in one side of said rotor, said valve element positioning
means adapted to reciprocably rotate said rotor relative to said
stator between a first position wherein said inlet port is in fluid
flow communication with one of said metering outlet ports through
one of said channels and a second position wherein said inlet port
is in fluid flow communication with the other metering outlet port
through the other of said channels.
18. The system of claim 17 wherein said channels are spaced from
one another by a bridge element having a width less than the diameter
of said inlet port; said valve element positioning means upon de-energization
of said system positioning said bridge element over the center of
said inlet port whereby pressurized fluid from said inlet port may
enter both of said channels, each of said channels when in said
later position being in fluid flow communication with one of said
drain ports.
19. A flowmeter system comprising, in combination:
valve means having a movable rotary valve element and defining
a fluid inlet port, a drain port and two metering outlet ports;
metering means connected to said metering outlet ports and including
a metering element movable between a first position and a second
position in accordance with the direction of fluid flow through
said metering means;
a reversible electric motor having an output shaft interconnected
with said rotary valve element;
means responsive to movement of said metering element to each of
said positions to energize said electric motor to rotate said rotary
valve element and reverse fluid flow direction through said metering
means; and
means responsive to de-energization of said system to rotate said
motor output shaft and rotary valve element until said fluid inlet
port is in communication with said drain port and fluid entering
the fluid inlet port bypasses the metering means.
20. The system of claim 19 additionally comprising means for detecting
movement of said metering element to said positions, said detecting
means including a signal element connected to said metering element
and switch means responsive to movement of said signal element.
Description BACKGROUND OF THE INVENTION
The present invention relates to flow meters, and more particularly,
relates to a selectively energizable flow meter system adapted to
accurately meter the flow of pressurized fluid continuously delivered
to the system as by means of a high pressure pump. During operation
of the system the pressurized fluid passes through both a valve
means and metering means incorporated in the system. When the system
is de-energized, means is provided to adjust a movable valve element
of the valve means so as to bypass the metering means and prevent
harmful pressure build-up in the system due to the continuing functioning
of the high pressure pump.
SUMMARY OF THE INVENTION
According to the present invention, a fluid flow meter system is
provided which is highly accurate and reliable in construction and
readily lends itself to the metering of high pressure fluid being
continuously delivered thereto. The system includes a valve means
defining at least one fluid inlet port for receiving the fluid under
pressure and a plurality of fluid distribution ports. The valve
means includes a valve element selectively movable to direct the
liquid to predetermined fluid distribution ports. The valve means
directs the fluid to metering means having a reciprocating metering
element movable between two positions. Valve element positioning
means is connected to the valve element to selectively position
same when the metering element reaches each of said positions. Thus,
pressurized fluid will be continuously delivered to the metering
means along alternative flow paths interconnecting the metering
means and valve means. Movement of the metering element under the
urging of the pressurized fluid will in turn force an equal amount
of fluid from the metering means back through the valve means. The
valve element positioning means is operable upon de-energization
of the system to direct pressurized fluid entering the valve means
fluid inlet port to a valve means fluid distribution port bypassing
the metering means.
Other objects and characteristics of the invention will be apparent
from the following more detailed description and accompanying drawings
in which :
DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic diagram of apparatus incorporating the principles
of the invention;
FIG. 2 is an enlarged detailed partial broken away view illustrating
the operative details of stator and rotor components of the valve
means of the apparatus;
FIGS. 3 and 4 are sectional views taken along lines 3 and 4 respectively,
of FIG. 2;
FIGS. 5-7 are schematic presentations showing interaction between
the valve means and metering means at various stages of operation;
FIG. 8 is a view taken along line 8--8 of FIG. 7; and
FIG. 9 is a schematic side view of an alternative form of signal
element that may be employed in association with the valve means
of the apparatus.
DETAILED DESCRIPTION
Referring now to FIG. 1 a preferred form of apparatus constructed
in accordance with the present invention includes a metering device
generally designated by the reference number 12 and comprising a
cylindrical housing 14 having a reciprocating metering element in
the form of a piston 16 slidably disposed therein in fluid tight
relationship. At the ends thereof the interior of housing 14 is
in fluid flow communication with a valve 20 through conduits 22
and 24. It will be appreciated that pressurized fluid flowing from
the valve through one of the conduits will cause piston 16 to move
in a predetermined direction within the housing thus forcing fluid
from the housing through the other conduit and back to the valve.
Means is provided for detecting when the piston 16 is at a predetermined
location in the housing. The detecting means includes a signal element
26 disposed outside the housing and connected to piston 16 as by
means of a rod projecting into the housing. It should be noted that
the rod projects from both ends of the piston to ensure that volume
changes occur equally in the housing upon piston movement. Optical
switches 28 and 30 detect the end of travel for the reciprocating
piston 16 by sensing the ends of a slot 32 formed in the signal
element. Signal element 26 also has indicia formed thereon sensed
by photoswitch 34. The outputs of optical switches 28 and 30 and
photoswitch 34 are connected to microprocessor 36 which incorporates
suitable circuitry to calculate the flow rate within metering device
12 by measuring the time interval between edge transitions from
photoswitch 34. Digit drivers 40 and segment drivers 42 are connected
to such circuitry. The microprocessor sends time multiplexing segment
information to the segment drivers 42 and scans the four digit drivers
40 to display the flow rate on four LEDs 44. An oscillator 50 with
a variable resistor 52 is connected to the microprocessor to permit
calibration of the metering device.
The microprocessor employed in the disclosed arrangement is preferably
the Model 8048 microcomputer commercially available from Intel Corporation,
suitably programmed to perform the functions attributed to microprocessor
36 herein. It will be appreciated that other alternative suitable
circuitry for performing the microprocessor functions may be employed
as desired.
As may best be seen with reference to FIGS. 1-4 valve 20 includes
a stator 54 and a rotor 56. Stator 54 has five ports formed therein,
namely a fluid inlet port 58 and a plurality of fluid distribution
ports 60 62 64 and 66. Through a conduit 68 fluid inlet port 58
is connected to the source (not shown) of high pressure fluid to
be introduced into the system. Rotor 56 has arcuate channels 67
and 69 formed therein for selective communication of the ports through
the channels upon rotation of the rotor. The rotor is movable between
two extreme positions, the first of which shown in FIG. 5 results
in high pressure fluid passing from inlet port 58 to fluid distribution
port 60 and thence through conduit 22 to the metering device, and
the second of which shown in FIG. 6 results in fluid passing from
the inlet port through distribution port 66 and conduit 24 through
the metering device. At the same time one of the channels formed
in the rotor completes the fluid path between the inlet port and
one of the distribution ports leading to the metering device, the
other of said channels completes a fluid flow path between the distribution
port connected to the discharge end of the metering device to one
of ports 62 and 64 which deliver fluid from the system after it
has been metered.
Rotor 56 is connected to the output shaft of a reversible motor
80 said motor serving to move the rotor between the two extreme
positions just described. Motor 80 is in operative association with
motor driver 82 which receives a signal from microprocessor 36 when
optical switches 28 and 30 detect the end of travel for the reciprocating
piston 16. The motor driver 82 will then become activated and reversible
motor 80 will continue to turn until fluid flow within the metering
device 12 and conduits 22 and 24 is reversed.
Also connected to the output shaft of motor 80 is a disk 84 which
turns with the rotor. A gap 86 is formed in the disk with the edges
of the disk defining the gap coming into the proximity of optical
switch 88 when the rotor has been positioned to reverse flow as
previously described. Optical switch 88 will then send a signal
to the microprocessor de-activating motor driver 82 and stopping
rotation of the motor output shaft. It will appreciated that this
activity will be on a continuous basis while the meter system is
energized so that a continuous flow of fluid through the metering
device and out of the system will occur.
The system is connected to a source of electricity through double
pole switch 90 so long as the switch is closed. When the system
is de-energized by opening switch 90 interrupt line 92 will detect
such action and microprocessor 36 will activate keep alive circuit
94 to maintain the supply of AC power to power supply 96 which is
in the form of an AC to DC transformer. Microprocessor 36 will then
turn the motor 80 until the valve rotor 56 has reached a safe stop
position wherein high pressure fluid entering the valve will bypass
the metering device and exit directly from the valve. This position
of the rotor is illustrated in FIGS. 7 and 8 wherein the bridge
between the channels 67 and 69 is positioned over the center of
the inlet port 58 with the other ends of the channels connecting
the inlet port directly to ports 62 and 64. In this manner, no potentially
harmful pressure build-up will occur in the system even though pressurized
fluid is being delivered thereto. At the time the rotor bridge element
is centered over the stator inlet port a slot 98 formed in disk
84 will be in alignment with an optical switch 100. When this safe
stop position is detected by optical switch 100 it will send a signal
to microprocessor 36 to de-activate the keep alive circuit 94 and
allow the flow meter system to power down.
It will be appreciated that the system as disclosed may be modified
somewhat without departing from the spirit of the invention. For
example, FIG. 9 illustrates an alternative form of signal element.
The signal element is in the form of a disk 112 having indicia thereon.
A rack and pinion arrangement 114 connected to piston 16 will serve
to rotate disk 112. This arrangement provides for somewhat greater
accuracy during the detecting stage since more of the disk surface
will pass by its associated detector switches (not shown) due to
piston movement than is the case with the linear signal element
shown in FIG. 1.
|