Note: Descriptions are shown in the official language in which they were submitted.
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,
POWER GENERATION FOR VALVE ACTUATORS
This application is a divisional of Canadian National Phase Application Serial
No. 2,644,180 filed March 7, 2006.
TECHNICAL FIELD
The present invention relates generally to valve actuators, and more
particularly, to power generation for the electronics of a valve actuator.
BACKGROUND
= Valve actuators are used to operate valves and are manufactured in
numerous
shapes, sizes, forms and have a wide variety of utilities. It is common for an
operator
of a valve actuator to want to know the specific position of a valve. Absolute
encoders
and incremental encoders have been utilized with valve actuators to determine
the
position of a valve. The encoders monitor the position of the valve actuator
to
determine the corresponding position of a valve.
Absolute encoders utilize a unique signature for each position of a valve
actuator. Absolute encoders often comprise either a single disc or multiple
discs that
are rotated as a valve actuator moves to different positions. The single or
multiple
discs of an absolute encoder have markings, different combinations of which
provide a
unique signature for each position of a valve actuator. This unique signature
can be
analyzed at any time to determine the position of the valve actuator.
Incremental encoders, on the other hand, do not have a unique signature for
each position of the valve actuator. Instead, incremental encoders monitor
changes in
the valve actuator relative to an arbitrary starting point, such as the fully
closed position
of a valve. An incremental encoder, also referred to as a relative encoder,
may be a
single disc with a series of duplicate markings around the edge of the disc.
As the disc
is rotated, each time one of the marks passes a point, a change in position is
recorded.
For example, if a disc had one hundred marks around the edge of the disc, the
disc
could be rotated multiple times and so that several hundred marks could be
counted to
indicate changes in position. As long as the marks are recorded in the memory
of a
computer, then the valve actuator position is known and can be indicated by on-
board
electronics using status contacts, data bits in user readable data registers,
or
alpha-numeric displays.
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Valve actuators will often have a handwheel, as well, in case the electric
motor
should either fail or there should be a power failure, so that manual
operation of the
valve is available. However, a loss of power could result in an erroneous
position
indication if the handwheel is moved while the power is down and there is no
backup
or redundant power supply. After the handwheel is moved, the lack of updating
can
result in a valve actuator indicating one position, when in fact, the valve is
in a different
position. Actuators using absolute encoders automatically correct the position
indication as soon as power is restored. Acuators using incremental encoders
must
have a bacicup or redundant power supply to allow them to avoid total loss of
position
knowledge during a power outage. For this case, when power is lost, the
incremental
encoder either reverts to its startup position, or its current count is saved
to a
non-volatile memory location in the on-board electronics. If the handwheel is
moved
on an incremental encoder system, the electronics will continue to track the
position as
long as the backup or redundant supply remains alive. If, however, the backup
or
redundant power supply dies (ex: dead battery), then the incremental encoder
based
actuator system will lose its proper sense of position if the user moves the
handwheel
after the backup or redundant power supply dies. Incorrect position
information could,
in turn, lead to valve damage and incorrect operation of a process controlled
by the
valve. Either absolute or incremental encoder based systems can maintain
proper
position information on loss of normal power, as long as there exists a backup
or
redundant power supply. An absolute encoding system may lose its ability to
indicate
the proper position during a total power loss, but it will immediately recover
on the
restoration of power. The incremental system, on the other hand, will need to
be
recalibrated after a total power loss if the user has also moved the handwheel
during the
power outage. Users are typically reticent to move a valve that is operating
in an active
process just to recalibrate the position sensor. To do so, even on a single
valve, often
requires a complete plant shut down.
The sensing of position information from either an absolute or an incremental
encoder requires electrical power. Additionally, when an incremental encoder
is used,
there is an additional power requirement for storing position information in a
memory.
Absolute encoders do not require the storage of position information since the
information can be readily ascertained from the absolute encoder. Valve
actuators that
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utilize incremental encoders require battery back-up to maintain position
information in
the event of a power failure. For both absolute and incremental encoders, a
back-up
power source is necessary to display position information during a primary
power
failure.
There is a need in the art for electronically displaying updated position
information during manual operation of a valve actuator without the need for a
back-up
battery. A need exists in the art for powering the other electronic components
of a
valve actuator. Additionally, there is a need in the art for providing
electrical power to
hydraulic and pneumatic valve actuators without the need for supplying
electricity
from an external source.
DISCLOSURE OF THE INVENTION
One embodiment of the invention is a method of electrically powering a portion
of a valve actuator comprising operating the valve actuator to generate
mechanical
energy, converting a portion of the mechanical energy into electrical energy,
and
electrically powering the portion of the valve actuator with the electrical
energy.
=
One embodiment of the invention includes a system for electrically powering
accessory electronics of a valve actuator, the system comprising a valve
actuator, and
an electrical generator adapted to electrically power the accessory
electronics of the
valve actuator.
One embodiment of the invention includes a power source for a valve actuator
comprising a power generation means, an input means adapted to transfer
mechanical
energy from a drive train of the valve actuator to the power generation means,
an
engagement means adapted to operatively couple the input means to the power
generation means, and a control means adapted to control when the engagement
means
operatively couples the input means to the power generation means.
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According to one aspect of the present invention, there is provided a valve
actuator comprising: a drive train; and an electrical generator connected
mechanically with the
drive train.
According to another aspect of the present invention, there is provided a
power
source for a valve actuator, the power source comprising: a power generation
means; and an
input means adapted to transfer mechanical energy from a drive train of the
valve actuator to the
power generation means.
According to yet another aspect of the present invention, there is provided a
valve
actuator comprising: a drive train comprising: a handwheel; an electric motor;
and an electrical
generator connected mechanically with the drive train, the electrical
generator adapted to receive
energy from manual operation of the valve actuator by the handwheel.
According to still another aspect of the present invention, there is provided
a
power source for a valve actuator, the power source comprising: a power
generation means
comprising an electrical generator adapted to electrically power accessory
electronics of the
valve actuator; and an input means comprising a manual operation mechanism,
the input means
adapted to transfer mechanical energy from a drive train of the valve actuator
generated by
manual operation of the valve actuator by the manual operation mechanism to
the power
generation means.
The features, advantages, and alternative aspects of the present invention
will be
apparent to those skilled in the art from a consideration of the following
detailed description
taken in combination with the accompanying drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and
distinctly claiming that which is regarded as the present invention, the
advantages of
this invention can be more readily ascertained from the following description
of the
invention when read in conjunction with the accompanying drawings in which:
FIG, 1 illustrates an electrically driven valve actuator;
FIG. 2 Must' _________________ ates a pneumatically driven valve actuator;
FIG. 3 illustrates one embodiment of a power source according to the present
invention;
FIG. 4 is a cut-away view of the embodiment depicted in FIG. 3 showing an
energized solenoid and a disengaged clutch; and
FIG. 5 is a cut-away view of the embodiment depicted in FIG. 3 showing a
de-energized solenoid and an engaged clutch.
DETAILED DESCRIPTION OF THE INVENTION
The methods, apparatus, and systems of the present invention may be utilized
to provide electrical power to a valve actuator. In one embodiment, the
present
invention may be used to provide power to an electrically driven valve
actuator in the
event of a power failure. In other embodiments, the present invention may be
used to
power electronic equipment on a non-electrically driven valve actuator.
Examples of
non-electrically driven valve actuators include manuAlly operated valve
actuators (such
as those driven by handwheels or levers), pneumatic valve actuators, and
hydraulic
valve actuators. The present invention may be utilized with any type of motive
source
for valve actuators known in the art. The present invention may also be
utilized for
electrically driven valve actuators where electricity for operation of the
motor is
present, but it is desirable to provide a different electric power source for
the other
electronic components of the actuator. The present invention may be utilized
to
provide power to any electrical component of a valve actuator, excluding an
electric
motor prime mover of an electrically driven valve actuator.
FIG. I illustrates an electrically driven valve actuator without the present
invention. FIG. I illustrates just one version of an electrically driven valve
actuator
and is not intended to limit the applicability of the invention to any
electrically driven
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or other valve actuator. Valve actuator 20 includes electric motor 4 coupled
to worm
shaft 3. Handwheel 1 is connected to handwheel adapter 11. Handwheel adapter
11 is
connected to drive sleeve 2. Drive sleeve 2 is connected to valve stem nut
(not shown).
Worm gear 10 mates with worm shaft 3. Worm gear 10 is also coupled to a valve
stem
nut, which is able to drive the valve stem of a valve. In FIG. 1, valve
actuator 20 is not
shown attached to a valve. Operation of either electric motor 4 or handwheel 1
raises
or lowers a valve stem. The valve stem is able to travel up and down through
the
center of handwheel 1. The valve stem may also rotate and either operate a nut
in the
valve which can either open or close the valve or can directly rotate a valve
to an open
or close position (for example, as in a butterfly, vane, or ball valve).
Valve actuator 20 may include any drive train, hardware, devices, electronics,
and/or software utilized in operating a valve. Valve actuator 20 may be
designed for
any type of valve, including for example, linear, quarter-turn rotary, multi-
turn rotary,
ball, plug, gate, butterfly, and diaphragm valves. The components of valve
actuator 20
may be arranged in any fashion. Handwheel 1 may be oriented to the side of
valve
actuator 20, as is known in the art.
The drive train encompasses any prime mover, any manual operation
mechanism, any disengagement or isolation mechanisms, braking mechanisms, any
speed modulation mechanisms, and the mechanisms for attachment to a valve. A
drive
train may also exclude any of the above elements or also include additional
elements.
For purposes of illustration only, FIG. 1 shows electric motor 4 as the prime
mover and
handwheel 1 as the manual operation mechanism. Often, a clutch mechanism will
be
included so that operation of either electric motor 4 or handwheel 1 does not
result in
operation of the other. By way of example, a lever 5 and a declutch mechanism
13 can
be provided as the disengagement or isolation mechanisms. Numerous clutch and
engagement mechanism are known in the art. Declutch mechanism 13 may be
designed to engage or disengage any portion of the drive train of valve
actuator 20.
In FIG. 1, the braking mechanism and speed modulation mechanisms are both
incorporated in worm shaft 3 and worm gear 10. Instead of, or in addition to,
worm
gear 10 and worm shaft 3, other gear types or no gears may be used in valve
actuator 20. Gear types for valve actuators are often selected based upon the
amount of
speed reduction, if any, between electric motor 4 and valve stem nut.
Hereinafter,
_ _
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when referring to the gears of the drive train of a valve actuator, the
example of a worm
gear and a worm shaft are primarily utilized. However, it should be understood
that the
discussion may be applied to any gear. If a gear is not present in the valve
actuator,
then output mechanism of any applicable prime mover may also suffice.
In the example of HG. 1, the mechanisms for attachment to a valve may be a
valve stem nut and associated supporting structures, as are known in the art.
However,
any mechanism for attachment known in the art may be utilized. The term
"valve" as
used herein encompasses the most generic uses of the term as used in the art,
including
the definition of a device that at least partially controls the flow of a
liquid, gas, and/or
solid. Electric motor 4 may be any electrically driven prime mover capable of
operating a valve actuator.
FIG. 1 also illustrates a few of the accessory or auxiliary electrical
components
of a valve actuator. The terms "accessory" and "auxiliary" as used herein
refer to any
portion of the components of a valve actuator that utilize electricity, other
than the
electric motor itself. A particular embodiment of an encoder 6 is illustrated
as a
multi-wheel absolute encoder. Encoder 6 may also be a single wheel absolute
encoder
or an incremental encoder. Numerous encoders are known in the art. FIG. 1 also
illustrates control module 8 for controlling electric motor 4, and depicts
circuit
board 15 for receiving inputs from control panel 7 and for sending outputs to
indicator 12.
In this particular example, indicator 12 is illustrated as a liquid crystal
display
(LCD). One or more indicator(s) 12 maybe present. A few non-limiting examples
of
indicators include light-emitting diode lights (LED) and displays, filament
lights, and
dials. Numerous indicators for valve actuators as known in the art can be
used, such as
electrically powered pointers.
Any number of accessory electrical components (not shown) may be present in
a valve actuator and be supplied power by the present invention. For example,
numerous types of sensors for monitoring encoder 6 may also be present and
require
electrical input. A few non-limiting examples of sensors are optical sensors,
magnetic
sensors, and Hall effect sensors. Valve actuator 20 may also include any
number of
sensors for other purposes as well. Processors and associated elements (e.g.,
diodes,
gates, resistors, etc.) may also be present for converting signals from the
sensors into
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valve position data. Memory may also be present for retaining position data.
Of
course, processors, memory, and a wide variety of other circuit board elements
unrelated to encoder 6 and any sensors may also be present and be powered by
the
present invention.
The present invention is not limited to any particular valve actuator and may
be
applied to any valve actuator. FIG. 2 illustrates a pneumatically driven valve
actuator,
valve actuator 40, as known in the art. Valve actuator 40 is shown mated to
valve 36
and actuator stem 22 is coupled to plug 30. The movement of actuator stem 22
results
in corresponding movement of plug 30, which governs the operation of valve 36.
Valve 36 may be a globe, gate, ball, butterfly, plug, diaphragm, or any other
type of
valve operable by an actuator. Actuator stem 22 and plug 30 are illustrated
for a
representative globe valve. However, it should be understood that either
component
may be modified depending upon the type of valve present. Additionally, when
the
phrase "drive train" is used hereinafter, the phrase encompasses the drive
components
of valve actuator 40, such as actuator stem 22.
Valve actuator 40 may also include any number of electronic components, such
as, for example, position sensors, circuit boards, and indicators. Any
electronic
devices, hardware, and/or software known in the art for valve actuators may be
included. Any electronic components of valve actuator 40 may be powered by the
present invention.
The present invention utilizes operation of a valve actuator to generate
electrical power. In a particular embodiment, a portion of the mechanical
energy
generated by operation of a valve actuator is converted to electrical energy.
The
mechanical energy may be converted to electrical energy while the valve
actuator is
operating or the mechanical energy may be stored for later conversion. In an
alternative embodiment, operation of the valve actuator triggers the
generation of
electrical energy via the generator. The valve actuator may be operated
manually,
electrically, pneumatically, hydraulically, or otherwise. It is preferable
that the
conversion be accomplished by a generator; however, any source that may be
used to
generate electricity may be utilized with the present invention, including
drives other
than directly from actuator's drive train.
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"Generator" or "power generation means" as the terms are used herein
encompasses rotary, reciprocal, linear, and piezoelectric generators, as well
as any
other means, for generating power known in the art. The generators may operate
based
upon electromagnetic induction principles, piezoelectric principles, or any
other
principle known in the art. The term "generator" encompasses both AC
production,
such as by an alternator, and DC production. For rotary generators, the main
components are a rotor and a stator. Often, the rotor is a magnet such as a
permanent
magnet or an electromagnet. A rotor with a single magnet is referred to as
having
two-poles (north and south poles). A rotor with two magnets is referred to as
having
four-poles. A rotary generator of the present invention may have any number of
poles.
The stator is often comprised of a coil of copper wires. Any wires or material
capable
of having current induced therein may be used with the present invention.
Rotation of
the magnet induces current into the wires of the stator. Alternatively, wires
may be
rotated around a magnet to induce current into the wires. The term "magnet,"
as used
herein refers to any means of generating a magnetic field known in the art.
In a particular embodiment, the generator includes a component of the valve
actuator driven by the drive train. In another embodiment, the generator may
be
attached externally to a valve actuator, such as near a handwheel, near a
valve actuator
output, or near a valve stem. In other embodiments, the generator is not
attached to the
valve actuator. For example, the generator may be attached to the valve.
Alternatively,
the generator may be separate from the valve actuator and the valve
altogether.
The generator may be able to directly receive mechanical energy from a drive
train of a valve actuator. The rotary, reciprocating, or linear movement of
any
component of the drive train may be used to operate the generator. In another
embodiment, the generator is able to receive mechanical energy from objects
acted
upon by the valve actuator. For example, a portion of the mechanical energy
imparted
to a valve stem could be transferred from the valve stem to the generator. The
movement of the valve stem may be utilized to operate the generator. In
another
embodiment, mechanical energy from the valve actuator is not used to operate
the
generator. Instead, a separate mechanical energy source may be utilized, such
as an
engine. In such an embodiment, operation of the valve actuator triggers
operation of
the generator.
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The generator may be adapted to receive mechanical energy from any
component of a valve actuator. The generator may be designed to receive
mechanical
energy from an input means, such as a rotating shaft, a gear, or a linearly
moving rod
driven by any valve actuator component. Alternatively, a drive train component
may
be adapted to serve as the input means for the generator. In one embodiment,
the input
means can be a shaft driven by a gear integrated with the drive sleeve, such
as drive
sleeve 2 (FIG. 1), of a drive train. In another embodiment, the input means
can be a
shaft, where a pinion on one end of the shaft mates with a worm gear, such as
worm
gear 10 (FIG. 1). The other end of the shaft drives the generator. In another
embodiment, the generator is driven by a worm shaft, such as worm shaft 3
(FIG. 1).
In an alternative embodiment, a gear rack could be integrated with an actuator
stem,
such as actuator stem 22 (FIG. 2). The rack could, in turn, drive a pinion as
the rack
moves up and down during actuation of a valve. The rotation of the pinion
could, in
turn, drive a rotary electrical generator. The input means may have one or
more
elements, such as, for example, a variety of shafts, gears, chains, belts,
pulleys, wheels,
couplings, hydraulic pumps and drives. It is contemplated that the input means
can be
driven by any component of the drive actuator that results in movement of the
tube,
output shaft, or drive sleeve. Any means for delivering mechanical energy may
be
used.
In a particular embodiment, the generator is designed to receive the
mechanical
energy while the valve actuator is operated. In one embodiment, the input
means
delivers the mechanical energy only when a valve is manually operated, such as
by a
handwheel or lever. This may be accomplished in a number of ways. For example,
the
input means may be adapted to move (such as linearly or rotationally) when the
valve
is manually operated. A non-limiting example of such a means includes
incorporating
a gear, such as a bevel gear, into a drive sleeve. An input means, such as
shaft with an
appropriate pinion, can be mated with the gear and with a generator. Rotation
of a
handwheel connected to the drive sleeve drives the generator.
In another embodiment where a valve actuator includes a clutch, declutching
the actuator results in decoupling the motor drive from the drive sleeve and
coupling
the handwheel into the drive train. This sometimes decouples the worm shaft,
but can
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also decouple the motor. Therefore, the input means of the generator could be
designed for intermittent or continuous operation.
Alternatively, the input means can move any time the valve actuator is
operated, but the input means is not able to deliver mechanical energy to the
generator
unless manual operation is used as the source of operation. When a valve
actuator is
operated, the input means can move, but mechanical energy would not be
delivered to
the generator. In this example, if the input means is driven off a component
that
always operates, then the input means would rotate any time the electric motor
or the
handwheel operates. However, if an engagement means, such as a clutch,
disconnects
the input means from the generator, then rotation of the input means does not
result in a
transfer of mechanical energy to the generator. The clutch may be controlled
by
control means, such as a solenoid, which only allows engagement when the
handwheel
is the source of operation. The solenoid could be triggered by a loss of power
or any
other known means. Therefore, only manual operation would result in a transfer
of
mechanical energy, but electrical operation would automatically declutch the
generator.
In another embodiment, any time a valve actuator is operated, a portion of the
mechanical energy can be converted to electrical energy. Using the previous
example,
if the clutch were always engaged, then the generator is activated any time
that the
valve actuator is operated. Alternatively, where the input means is driven by
components that move during operation of the valve actuator (such as, e.g.,
with
movement of an actuator stem), then the clutch may not be necessary. In this
scenario,
anytime the valve actuator operated, electricity would be produced.
In another embodiment, mechanical energy would be converted when an
electric motor is operating, but not when a handwheel is operating. This may
be
accomplished by driving the input means off of components that only move when
the
prime mover is operating.
Additionally, mechanical energy from the valve may be stored for later use by
the generator. Numerous ways of storing mechanical energy are known in the
art, such
as, for example, with a spring. The term "spring," as used herein, encompasses
single
or multiple springs. By way of example, multiple springs could be arranged in
series,
parallel. With such an embodiment, as the drive train of the valve actuator
turns (such
as a worm shaft or a worm gear), an input means (such as a shaft) operably
connected
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to the worm shaft or the worm gear could, in turn, be driven and wind up a
spring. The
spring may, in turn, be used to drive a generator. When the handwheel of the
valve
actuator is cranked, the stored mechanical energy in the spring is released to
drive the
generator. In this embodiment, a one time movement of the handwheel could
result in
power being generated, which power could be utilized for powering status
indicators
with a valve actuator. When power is restored and the electric motor is
operational, the
electric motor could rewind up the springs, or series of springs, through the
different
components of the drive train. The valve actuator will then be prepared for
the next
power failure.
It may also be advantageous to include a set of electrical contacts built into
the
valve actuator or, alternatively, built proximate to the valve actuator, where
the
electrical contacts may be used to sense a power failure. In this fashion,
when the
power has not failed, but an operator desires to manually operate the valve
actuator, the
generator would not be released.
A spring represents just one type of a mechanical energy storage device
suitable for use with the present invention. Other mechanical energy storage
devices
that can be used include, for example, a flywheel mechanism, compressed gas or
hydraulic accumulators. Where the mechanical energy storage device is operated
by
the drive train of the valve actuator, a spring can be used.
Although the generator has been described as receiving mechanical energy
from the valve actuator, it is also possible for the generator to receive
mechanical
energy from other sources. For example, the generator may be designed to
receive
energy from a gas motor. In this embodiment, the generator can act as an
external
engine-driven generator set which is utilized to power some or all parts of
the valve
actuator, except for an electric motor. In this embodiment, the external
generator could
still be triggered by operation of the handwheel. For example, operation of
the
handwheel could trigger electrical contacts, which would signal generator
start-up.
Additionally, a set of electrical contacts that sense whether normal power is
present can
also be included. In this embodiment, in order for the generator to start, the
handwheel
would have to be operated and normal power would have to be off. When the
generator is not relying upon the valve actuator to supply mechanical energy,
the
generator may still be a part of the valve actuator, either incorporated in
the valve
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actuator or mounted externally on the valve actuator. Additionally, other
mechanical
energy sources other than an engine may be utilized to power the generator.
Any suitable generator may also be integrated into the components of valve
actuator 20, such as, for example, rotary, reciprocating, linear, and piezo-
electric
generators. The principle components of those generators may be integrated
into valve
actuator 20. In an embodiment where it is only desirable to generate
electricity when
the handwheel is operated, the generator can be at least partially integrated
into the
components actuated by the handwheel. For example, drive sleeve 2 or handwheel
adapter 11 can serve as a rotor. Magnets (permanent or electromagnetic) can be
built
into or attached to either component in such a way as to generate an
electromagnetic
field with the appropriate orientation. Coils of wire can be integrated into
the housing
of valve actuator 20 that surrounds drive sleeve 2 or handwheel adapter 11.
Alternatively, conductive wires can be integrated into a rotary component,
such as
handwheel adapter 11 or drive sleeve 2, and magnets can be integrated into a
stationary
component of valve actuator 20. It is understood that any suitable way of
incorporating
a generator into the components operated by handwheel 1 can be employed.
In another embodiment, a generator may be integrated into components
operated by a prime mover, such as electric motor 4. For example, a rotary
generator
may be integrated into worm shaft 3 in a similar manner as discussed above
with
regard to handwheel adapter 11. A generator may also be integrated into worm
gear 10. In an alternative embodiment, a generator may be integrated into
actuated
components regardless of whether electric motor 4 or handwheel 11 is the power
source. For example, a generator may be integrated into valve stem nut.
Similarly, the generator may also be at least partially integrated into the
components of valve actuator 40. Magnets can be integrated into or attached to
actuator stem 22. A stator could then circumscribe actuator stem 22.
Alternatively, the
stator can be built into actuator stem spacer 24, actuator housing 26, or hub
housing 28.
The generator may also be partially or completely integrated with components
of a valve. In the embodiment of globe valve illustrated in FIG. 2, magnets
may be
integrated with or attached to plug 30. A stator can be integrated into bonnet
32.
Similarly, the generator may be integrated partially or completely with a
valve operated
by valve actuator 20. For example, a valve stem can be adapted to server as a
rotor.
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In all of the embodiments discussed herein, the generator may be used for
normal or intermittent operation. "Normal," as the term is used herein, refers
to the
usual operation of a valve actuator. For an electrically driven valve
actuator, normal
operation utilizes an electric motor, such as electric motor 4 (FIG. 1), to
operate a valve
actuator. Intermittent operation refers to operation via a handwheel, lever,
or other
manual operation device, such as handwheel 1.
Intermittent or normal operation may be governed by which component of a
valve actuator is driving the generator. If the component driving the
generator operates
normally then the generator will operate normally. Alternatively, the
generator may be
driven by a component which operates normally (e.g., worm shaft 3 of valve
actuator 20), but the generator may be intermittently operated. In this
embodiment, the
input means for the generator, which may be the drive train components or a
shaft, rod,
or gear driven by the drive train component, is separated from the generator
by a
disengagement means. The disengagement means may be a clutch or any other
device
for mechanically separating two components. Therefore, the input means may be
operated normally, but the generator will only be intermittently operated. The
engagement means may be governed by a control means.
For example, it may be desirable to have a control means which only allows
operation of the generator when the power supply for an electric motor, such
as electric
motor 4 (FIG. 1), is disrupted. The control means may be a solenoid, a
piezoelectric
material, an electrostrictive material, a magnetostrictive material, or any
device, or
combination of devices, that has different physical states depending upon the
presence
of electricity. For example, the position of a solenoid may depend upon
whether
current is present. Electrostrictive and magnetostrictive materials experience
elastic
strain when exposed to electric or magnetic fields, respectively.
Intermittent power generation may be useful in situations where the valve
actuator relies on electrical power for status indicators and other
electronics since the
main mode of power for the valve actuator is coming from compressed air.
Similar to
the pneumatic valve actuator, the present invention may also be used with
hydraulically
actuated valve actuators, or may be used with hybrid actuators such as, for
example,
gas over oil actuators, electrohydraulic fail-safe actuators, high pressure
gas powered
actuators and various combinations of electric, hydraulic, and/or pneumatic
actuators.
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The present invention may also be utilized with quarter-turn or multiturn
valve
actuators.
Additionally, it may be desirable to operate a generator at the same speed as
the
valve actuator, at a proportional speed relative to the valve actuator, or at
a constant
speed regardless of the speed of the valve actuator. A speed modulation means
may
therefore be added. The speed modulation means may receive mechanical energy
from
the input means and deliver the mechanical energy to the engagement means.
Alternatively, the speed modulation means may be disposed between the
engagement
means and a generator. The speed modulation means can include any suitable
mechanical device, such as gears, shafts, belts, friction devices, viscous
sheer coupling,
or wheels, for increasing, decreasing, or stabilizing the speed at which a
generator is
operated.
The speed modulation means may also include a transmission for operating a
generator within a range of speeds. The speed modulation means may vary
depending
upon the needs of the valve actuator. For example, a large valve actuator that
is
difficult to operate manually can turn at a slower speed than a smaller
actuator that is
easy to operate by hand. With regard to the larger valve actuator, it may be
necessary
to include more gears capable of increasing the input speed to a rotary
generator. A
smaller valve actuator may be capable of quicker rotation and, thus, need less
speed
increase.
In addition to the speed modulation means, power modulation means having
the necessary electronics to compensate for variations in speeds may be
provided. A
variety of diodes, regulators, transformers, and other electrical components
that are
known in the art may be utilized to maintain a constant voltage.
In a particular embodiment, the present invention can be used with an
electrically driven valve actuator. In another embodiment, when normal power
is not
supplied to the electrically driven valve actuator and the handwheel is
operated, enough
electrical energy is generated to power at least the local status indicators,
such as the
position indicators. Preferably, sufficient power is generated to power all of
the remote
and local indicators. Even more preferably, sufficient power is generated to
power all
of the accessory electronics of the valve actuator (i.e., everything but the
electric
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motor). The accessory electronics can include an absolute position encoder or
an
incremental position encoder.
The present invention may be used without a battery, to backup a battery, or
both may be used in tandem. Alternatively, the battery may be used to backup
the
present invention. A rechargeable battery can also be used as a backup
battery. The
rechargeable battery can be charged by the generator of the present invention.
In
another embodiment, a super capacitor can be charged while operating under
normal
power, which in turn, could power the electronics for weeks or months upon
loss of
normal power. The super cap could smoothly transition to act as the power
source
during any loss of normal power.
The present invention also includes an electrical power storage means, not to
be
confused with the previously discussed mechanical energy storage device. In
addition
to the batteries and rechargeable batteries, the electrical energy storage
means may also
include, for example, capacitors, inductors, and/or bladders. The electrical
power
storage means may serve various functions, including to clean the energy being
produced by the generator. The electrical energy generated by the manual
operation of
the handwheel, by the operation of springs, or by some other source, may be of
variable
consistency. Variations in the speed at which a generator is turned can cause
numerous
problems. For example, for an AC generator, the speed of the generator
determines the
voltage and frequency of the power output. Components of the valve actuator
that run
on AC may only be designed to handle fifty or sixty Hertz of electrical input.
Additionally, variations in voltage may be unacceptable for certain electronic
devices.
For DC generators, variations in speed may result in variations in power
output. Many
electrical power storage means are designed for DC output. In the embodiment
where
the means is a battery, the battery can receive electrical input of varying
quality but
can, in turn, output a more consistent quality of electricity. Additionally,
power
modulation means (such as, for example, transformers, rectifiers, converters
or
inverters) may be utilized to control the type and quality of the electricity
transmitted to
valve actuator electronics.
The present invention encompasses operating the generator any time the
electric motor operates the valve actuator. For example, where the valve
actuator is
designed so that the status indicators and other accessory electronics are
positioned on
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a separate circuit relative to the electric motor, both circuits must be
powered in the
event of a power failure. Alternatively, the present invention may be utilized
to
generated electricity when the electric motor is operated, thus eliminating
the need to
power both circuits.
Another embodiment where the present invention may be utilized includes a
valve actuator that has a handwheel and does not have any other type of prime
mover.
This can provide power for electrical or digital position readout or other
status
information for systems found in remote locations. The power generated by the
generator may be utilized to power numerous electronics and devices. In a
valve
actuator having only a handwheel, the valve actuator may also be coupled to
the
transmitter, which can transmit either through land lines, wireless
communications, or
satellite communications the updated position of the valve as it is actuated.
The present
invention provides a way to provide power to previously isolated valve
actuators.
Similar to the valve actuator with only a handwheel, another embodiment
includes power takeoff or PTO driven valve actuators. The generator of the
present
invention may be coupled to a PTO driven valve actuator to generate
electricity for use
with indicators or any electrical component. The present invention may be
designed as
a device that is sold with new valve actuators or it may be designed to
retrofit old valve
actuators.
The power source of the present invention may be designed for providing
electrical power during operation of the valve actuator, immediately after
operation, or
both. Additionally, the generator and associated input means may be designed
to
provide enough power to power any accessory electronics for an extended period
of
time. The extended period of time is limited only by the type of generator and
energy
storage device that is employed.
FIGS. 3-5 illustrate one embodiment of a power source 50 of the present
invention. In this embodiment, the power generation means is a rotary
generator.
Generator 1000 is turned via gears 500 by an input shaft 400. Input shaft 400
may be
designed for normal operation, such as where input shaft 400 is connected to
the drive
train of a valve actuator. In a particular embodiment, input shaft 400 is
connected to
the handwheel, such as handwheel 1 (FIG. 1), of a valve actuator. Gears 510,
530, 550
and 570 are utilized to increase the speed of input shaft 400 so that input
shaft 1100 of - -
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generator 1000 rotates at a much higher speed. Gear 510 is shown with the
teeth on the
gear. Although not shown, teeth may also be present on gears 530 and 550 and
pinions 540, 560, and 570. Gears 530 and 550 and pinions 540, 560, and 570 are
illustrated as spur gears. However, any type of gear may be utilized, such as
worm,
bevel, helical or any other type of gear. Attached to the underside of gears
530 and 550
are pinions 540 and 560, respectively. Gear 510 mates with pinion 540, which
chives
gear 530; gear 530 mates with pinion 560, which drives gear 550. Gear 550, in
turn,
mates with pinion 570. In this manner, input shaft 1100 receives an increased
speed
input. Gears 510, 530, and 550 and pinions 540, 560, and 570 (collectively
"gears and
pinions") represent one embodiment of a speed modulation means. The ratio of
teeth
between the gears and pinions can be adjusted as necessary to provide the
proper input
speed to input shaft 1100. Additionally, fewer or more gears and pinions may
be
utilized. The gears and pinions may be located between clutch 600 and
generator 1000, as depicted. Alternatively, the gears and pinions may be
located
between the drive train and the input means. It is also understood that
increasing
generator speed is not always necessary and, in fact, there may exist
situations where
reduced speed input may be desired.
In the present embodiment, generator 1000 is mounted to mounting plate 100.
Generator 1000 is shown with housing 1200. However, it is understood that
housing 1200 may or may not be present. Solenoid 200 is also mounted to
mounting
plate 100. Solenoids are well known in the art. In a particular embodiment,
solenoid 200 is an electrical solenoid. However, solenoid 200 may include any
suitable
solenoid, such as a pneumatic or hydraulic solenoid. Solenoid 200 includes
plunger 220 and a solenoid spring (not shown). Solenoid operation is well
known in
the art. Plunger 220 has an iron core which is attracted to an electric coil
(not shown)
inside of the solenoid. When current is traveling through the coil, the iron
core of
plunger 220 is attracted and moves towards the center of the coil. The
solenoid
spring is attached to plunger 220 in opposition to the coil and the spring is
extended
whenever current is flowing through the coil. When current is not flowing
through the
coil, the solenoid spring retracts the plunger away from the center of the
coil.
Alternatively, the solenoid spring may be compressed whenever the coil is
energized.
Of course, numerous variations in solenoid 200 are possible. Solenoid 200 is
just one
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embodiment of a control means for the engagement means. Any suitable control
means known for engaging clutch 600 may be used. It is also understood that
other
embodiments are envisioned where solenoids are not included.
Lever 300 is attached to mounting plate 100. Lever 300 includes handle 340
and lever arms 360. Plunger 220 of solenoid 200 engages handle 340 of lever
300.
When the coil of solenoid 200 is energized, plunger 220 is retracted, causing
lever 300
to pivot so that lever arms 360 are in a down position. When the coil is de-
energized
then plunger 220 extends, pushing against handle 340 and pivoting lever 300
such that
lever arms 360 move into an up position. Lever arms 360 engage clutch 600.
When
plunger 220 is extended, clutch 600 is raised and results in input shaft 400
engaging
gear 510. Lever 300 is part of one embodiment of an engagement means.
FIG. 4 illustrates the operation of clutch 600 when the coil of solenoid 200
is
energized. FIG. 5 illustrates operation of clutch 600 when the coil is de-
energized.
Referring to FIG. 4, clutch 600 includes clutch spring 620. Clutch spring 620
opposes
the movement of arms 360 of lever 300. Clutch spring 620 is shown as being
inside
clutch 600. However, clutch spring 620 may also be around, above, or beneath
clutch 600. Clutch spring 620 is shown as being compressed whenever lever arms
360
are raised into the up position. Alternatively, clutch spring 620 may be
elongated
whenever lever arms 360 are raised to the up position.
In another embodiment, clutch spring 620 may not be present. Clutch
spring 620 serves to pull clutch 600 into a down position whenever lever arms
360 are
moved to the down position. In FIGS. 3-5, lever arms 360 push against a flange
of
clutch 600. However, if lever arms 360 are permanently secured to clutch 600,
and
lever handle 340 are secured or attached to plunger 220, then as plunger 220
is
retracted by energizing the coil, clutch 600 will in turn be pulled into the
down
position. Therefore, there is no need for clutch spring 620. Lever arms 360
may be
secured temporarily or permanently to clutch 60 in any fashion.
Clutch 600 and, optionally flat surface 700, comprise a particular embodiment
of an engagement means. Alternatively, clutch 600 may be a transmission, such
as an
infinite velocity drive where, regardless of the speed of input shaft 400,
generator 1000
is turned at the same speed.
_
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The functions of solenoid 200, lever 300, and clutch 600 may be performed by
a single device. For example, clutch spring 620 can also serve the function of
a
solenoid spring. Clutch 600 can be adapted so that the coil, when energized,
attracts
clutch 600 towards the center of the coil. When the coil is de-energized, the
clutch
spring 620 can pull clutch 600 into engagement with gear 510. In that
embodiment,
there is no need for lever 300. The embodiment of power source 50 shown in
FIGS. 3-5 has a flatter profile. In an embodiment where the solenoid 200 and
clutch 600 are integrated into a single device, it is likely that the profile
would be more
raised. However, the overall footprint of that embodiment can be smaller.
Therefore,
the embodiment where solenoid 200 and clutch 600 are a single device may be
useful
where it is necessary to have a narrower power source.
Input shaft 400 is just one embodiment of an input means. Input shaft 400 may
be coupled to a valve actuator in any manner discussed above and below, or in
numerous other ways apparent to one of ordinary skill in the art.
Power source 50 may have any number of layouts. Power source 50 may be
designed to fit a wide variety of space constraints for a variety of valve
actuators. In
tandem with or in alternative to space constraint of the valve actuator, power
source 50
may also be designed around the physical constraints of the selected generator
1000.
Generator 1000 may be selected to meet a wide variety of criteria, such as,
for
example, the power supply needs of the valve actuator auxiliary electronics,
such as
voltage or power type, as in AC or DC. The current and frequency requirements
may
also be analyzed in selecting an appropriate generator 1000. Additionally,
generator 1000 may be selected simply because it is an off-the-shelf
generator. In
either scenario, power source 50 may be designed around the physical size and
mechanical input needs of generator 1000.
In a particular embodiment, generator 1000 is a rotary generator.
Generator 1000 may be a DC or an AC generator. Power can also be generated by
generator 1000 as gear 510 is turned. In another embodiment, however, the
mechanical energy transfer from input shaft 400 to gear 510, and eventually to
input
shaft 1100, may be stored. For example, housing 1200 may include a spring that
is
windable by input shaft 1100. When the spring is fully wound, the spring could
slip or
ratchet, thus preventing over-winding of the springõ Alternatively, a circuit
connected
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to the coil of solenoid 200 could be utilized to control when the spring is
wound up and
disengage clutch 600 to prevent overwinding. Electrical contacts can also be
provided
within generator housing 1200 to signal either a controller or solenoid 200 to
disengage
clutch 600 when the springs have been fully wound. The springs can then be
released
upon operation of a handwheel. Various mechanisms for releasing the springs
may be
utilized. Rotation of input shaft 1100 in an opposite direction can trigger
the release of
the springs. However, it is generally desirable that input shaft 1100 be
rotatable in
either direction. Alternatively, magnetic switches holding the spring in place
can be
released by signals controlled through movement of a handwheel.
In the embodiments discussed so far, clutch 600 can be disengaged whenever
the coil of solenoid 200 is energized. However, solenoid 200, and any other
components of power source 50, may be designed such that when the coil is
de-energized, clutch 600 is engaged.
FIG. 4 illustrates that clutch 600 engages gear 510 via a flat surface 700.
Flat
surface 700 may be part of one embodiment of an engagement means. However,
clutch 600 may be designed to engage gear 510 in numerous ways. FIGS. 4 and 5
illustrate one embodiment where clutch 600 is mechanically connected with gear
510.
Other mechanical means, such as the pressing of an elastomer pad between
clutch 600
and gear 510, may be utilized. Alternatively, clutch 600 and flat surface 700
may be
designed so they do not contact one another. For example, clutch 600 may be
designed
to hydraulically or magnetically engage flat surface 700 or gear 510. Clutch
600 may
be designed so that it turns whenever input shaft 400 is turning.
In one embodiment, input shaft 1100 and input shaft 400 are both designed to
rotate in two directions. Alternatively, input shaft 400 may be designed to
rotate in two
directions, but gearing may be present so that input shaft 1100 only turns in
one
direction. This may be accomplished so that movement of input shaft 400 in
either
direction may be transferred to input shaft 1100 or, alternatively, so that
only the
movement of input shaft 400 in one direction results in movement of input
shaft 1100.
In another embodiment, input shaft 400 is connected to a handwheel of a valve
actuator, such as handwheel 1, or to components operated by the handwheel. In
that
embodiment, input shaft 400 would only turn whenever the handwheel is
operated. In
certain situations, a handwheel may still be rotated manually even though
power is still
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available to turn an electric motor. In those situations, it may not be
desirable to
activate generator 1000 of power source 50. Therefore, the coil can be de-
energized in
order for the turning of input shaft 400 to also turn gear 510. The coil may
be
energized in numerous ways, as is known in the art. In one embodiment, the
coil
receives power from the same circuit that powers an electric motor, such as
electric
motor 4, of a valve actuator. Therefore, if power ceases to be supplied to the
controls
of the electric motor, then solenoid 200 de-energizes. Clutch 600 then engages
gear 510 and, should the handwheel be rotated, then generator 1000 will be
activated.
Additionally, a switch may be included whereby an operator may allow
operation of generator 1000 even though power is still available to an
electric motor.
For example, a switch may be included that opens the circuit energizing the
coil.
Clutch 600 engages gear 510 and any rotation of input shaft 400 results in
rotation of
generator 1000.
In another embodiment, input shaft 400 is rotated whenever the valve actuator
is operated. However, the operation of generator 1000 may still be controlled
by
whether the coil was energized or not. Therefore, generator 1000 will only be
rotated
whenever the valve actuator is operated without electrical input, such as
manually,
hydraulically, or pneumatically.
An energy storage device (not shown) may also be mounted on mounting
plate 100 and connected to generator 1000. The energy storage device may be
any
electrical power storage means previously discussed or known in the art.
Electronics 900 may also be mounted on mounting plate 100. Electronics 900
may be utilized to convert, invert, rectify, transform, clean, and/or control
the electrical
power delivered by generator 1000. Electronics 900 may be electrically
connected
between generator 1000 and the energy storage device. Alternatively,
electronics 900
may receive power from the energy storage device. For example, if generator
1000 is
an AC generator, then a converter may be utilized to convert the AC power to
DC
power for storage. Electronics 900 is one embodiment of an electrical power
modulation means. The electrical power modulation means and electrical power
storage means may be accomplished by the same device.
Numerous variations of each and all of the components of power source 50 are
within the scope of the invention. Power source 50 is shown as being mounted
on
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mounting plate 100. Generator 1000, solenoid 200 and the other components of
power
source 50 may be mounted to mounting plate 100 in any suitable way known in
the art.
Mounting plate 100 may be made out of a wide variety of materials, such as,
for
example, a metal or a semiconductor wafer. Mounting plate 100 is shown having
a flat
surface. However, mounting plate 10 may be any structure that connects the
different
components of power source 50. The term "components" as used in reference to
power source 50 refers to solenoid 200, lever 300, clutch 600, the gears and
pinions,
and generator 1000. The term "components" also refers to any devices
performing the
functions of those individual parts.
Additionally, in particular embodiments, mounting plate 100 may not be
included. For example, generator 1000 can be mounted to one portion of a valve
actuator, and solenoid 200 and clutch 600 could be mounted to other parts of
the valve
actuator. Alternatively, generator 1000, clutch 600 and the functions
performed by
solenoid 200 could all be integrated into a single device.
The components of power source 50 may be made from numerous materials.
Lever 300 and clutch 600, for example, may be made from materials such as
metals,
plastics, or resins. Mounting plate 100 may also be made from circuit board
materials
= or any other material compatible with such functions.
Input shaft 400 is shown in FIGS. 3-5 as being connected to input shaft 1100
via mechanical means. In the embodiment shown in FIGS. 3-5, the speed
modulation
means comprises mechanical means consisting of gears. However, other
mechanisms,
such as pulleys or wheels, may also be used to connect the two shafts.
Alternatively,
input shaft 400 may be connected to input shaft 1100 hydraulically, such as
via
hydraulic pumps and lines. Additionally, input shaft 400 may be fluidically
coupled to
input shaft 1100. Additionally, if it is not necessary to increase the speed
of input =
shaft 400, then input shaft 400 and input shaft 1100 can be directly coupled
to one
another, such as in an embodiment where the functions performed by solenoid
200 and
by clutch 600 are all integrated into a single device with generator 1000.
Although the foregoing description contains many specifics, these are not to
be
construed as limiting the scope of the present invention, but merely as
providing certain
exemplary embodiments. Similarly, other embodiments of the invention can be
devised which do not depart from the scope of the present invention. The
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scope of the invention is, therefore, indicated and limited only by the
appended claims
and their legal equivalents, rather than by the foregoing description. All
additions,
deletions, and modifications to the invention, as disclosed herein, which fall
within the
meaning and scope of the claims, are encompassed by the present invention.
