Note: Descriptions are shown in the official language in which they were submitted.
METHODS AND SYSTEMS FOR AIR COMPRESSOR WITH ELECTRIC INLET
VALVE CONTROL
CROSS REFERENCE TO RELATED APPLICATIONS
[0001]
This application is a Non-Provisional Patent Application of U.S. Provisional
Patent
Application No. 62/587,923 entitled "Methods and Systems for Air Compressor
with Electric Inlet
Valve Control" filed November 17, 2017.
BACKGROUND
[0002] Conventionally, engine-driven power systems are configured to power
multiple
components, such as generators, air compressors, welders, to name but a few.
Some air compressors
employ pneumatic valves to regulate intake and/or outflows of air. However,
pneumatic valves
require sensitive equipment and frequent maintenance to ensure proper
operation. Thus, systems and
methods that improve upon the shortcomings of pneumatic valves used in air
compressors is
desirable.
SUMMARY OF THE INVENTION
[0003]
Systems and methods are disclosed for an electric inlet valve control for an
air
compressor, powered and controlled by electrical devices, substantially as
illustrated by and
described in connection with at least one of the figures. In particular, a
system to provide electrical
control of an electric inlet valve for a rotary screw compressor based on one
or more control signals
is disclosed herein.
[0003A] An
aspect of the present invention provides for an air compressor control system
in an
engine driven welding power system having a user interface configured to
receive a command from
an operator corresponding to an operating capacity of the engine or a desired
air pressure level; a
sensor configured to measure one or more characteristics of the system
including a load on an engine
configured to drive the air compressor; an electric inlet valve integrated
within an air compressor
and configured to regulate airflow of the air compressor based on a position
of the
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electric inlet valve; and a controller configured to: receive information from
the user interface or
the sensor corresponding to the load on the engine; compare the information to
the operating
capacity of the engine; and adjust a position of the electric inlet valve via
an electrical control
signal in response to a determination that the load is greater than the
operating capacity of the
engine.
10003B1
Another aspect of the present invention provides for an air compressor control
system
in an engine driven welding power system including an electric inlet valve
integrated within an air
compressor and configured to regulate airflow of the air compressor based on a
position of the
electric inlet valve; and a controller configured to: determine an operating
capacity of the engine;
and compare a load on the engine to the operating capacity of the engine;
calculate a power
difference based on the comparison; calculate a pressure output of the
compressor based on the
power difference; and adjust a position of the electric inlet valve via an
electrical control signal to
limit the air compressor to the pressure output.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a functional diagram of an example power system, in
accordance with
aspects of this disclosure.
[0005] FIG. 2 illustrates an example control for an air compressor, in
accordance with the
present disclosure.
[0006] FIG. 3 is a diagram of an example air compressor with an exploded
view of an
electrically controlled inlet valve, in accordance with aspects of this
disclosure.
[0007] FIG. 4 is a diagram of another example air compressor with an
exploded view of an
electrically controlled inlet valve, in accordance with aspects of this
disclosure.
[0008] FIG. 5 illustrates an example method of operating a power system, in
accordance with
aspccts of this disclosure.
[0009] The figures are not necessarily to scale. Where appropriate, similar
or identical
reference numbers are used to refer to similar or identical components.
DETAILED DESCRIPTION
[0010] The present disclosure provides an electrically powered and
controlled inlet valve of a
rotary screw compressor. In examples, an electric current powering a stepper
motor (or, in some
examples, a linear solenoid or other electric powered motion device) is used
to open and/or close
an air passage completely or partially to control outlet pressure and/or
intake airflow of a rotary
screws compressor.
[0011] The electrically powered and controlled inlet valve (i.e. electric
inlet valve) works by
applying an electric voltage and/or current to a motor and/or solenoid to
adjust a mechanical
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valve. The change in position of the mechanical valve on the inlet side of the
compressor pump
restricts inlet airflow to the pump. The inlet airflow restriction produces an
outlet flow/pressure
reduction of the fixed displacement rotary screw pump. Thus, the output of the
compressor is
controlled by restricting the inlet airflow. The electric power to command
adjustment of the
electric inlet valve can be modulated and/or controlled to move the valve from
a closed position
to an open position, throttled in between, and vice versa.
[0012] Conventional air compressor systems employ pneumatic inlet valves to
throttle air
into the compressor (e.g., a rotary screw air compressor). The pneumatic valve
uses air pressure
from the compressor pump to close the valve. The pneumatic valve can be
controlled in a variety
of ways. However, even with an alternative control, the valve is still
pneumatically
implemented, such that air pressure is used to position the valve.
[0013] Advantages of employing an electrically powered and controlled inlet
valve include
obviating the need for air circuits to operate the pneumatic valve, which can
therefore be
removed. Additional control and ease of setting pressure and/or flow values of
the compressor is
also provided.
[0014] Further, pneumatic control circuits contain water, which tends to
condense out of the
air at pressure when the air in the control lines cools. In many situations,
such as in mobile
applications, the ambient temperature in which the compressor is operating is
often below
freezing. As the compressor cannot operate when water in the control lines
freezes, complex and
expensive heaters are often employed. The heaters are used to pre-heat the
control lines and
components to maintain a temperature above freezing, to keep the water in a
liquid form and
thereby to facilitate free flow through the control system. Employing an
electric inlet valve as
disclosed herein removes the pneumatic air control system, including pneumatic
tubes, hoses,
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regulating valves, passageways, etc., and therefore removes the issues that
stem from water
freezing in pneumatic controls during cold weather operations.
[0015] Conventionally, engine driven generators and air compressors systems
are either
driven at all times by a direct, continuous connection with the engine, or
intermittently via a
clutch or other variable and/or disconnecting member. Air compressors that
turn continuously
may be configured to stop producing air when pressurized output is not needed.
Cessation of
output from such air compressors can be achieved in a variety of ways, such as
by closing the air
compressor inlet, or diverting the unused air to be exhausted to the
atmosphere.
[0016] In the example of a fixed throttle air compressor driven by the
engine, this idle speed
varies depending on the engine temperature and compressor load, which are both
variables
dependent on ambient temperature, system temperature, operating conditions of
the components,
etc. Such conventional systems typically do not operate with other airflow
controls, since the air
compressor is either on or off.
[0017] Variable output (e.g., flow and/or pressure) air compressors are
desirable, however,
due to the lower operating costs associated with saved fuel and less demand
for maintenance.
Compressors that are configured to be disconnected from the engine have the
advantage of
turning on and off as needed. This is of particular value for engines
configured to power multiple
devices, such as an air compressor and/or a generator. For example, if only
output from the
generator is needed, the compressor can be turned off. If an output is needed
(e.g. pressurized
air), the clutch can engage the compressor and activate airflow to provide
pressurized air as
needed.
[0018] For a reciprocating type compressor, the clutch cycles on and off to
increase air
pressure within an air tank, or housing, as need. For a rotary screw
compressor, the clutch can be
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cycled by a pressure switch in the air tank. If no tank is being used, a
control scheme can
determine the timing and operation of the throttle at the air inlet to meet
output demand. For
instance, the inlet throttle control can be a proportional, electrically
controlled inlet valve that
adjusts the position of the valve to change inlet pressure to meet a target
output pressure level.
The electric inlet valve can be configured to partially open to control flow
levels, as well as
opening fully to allow maximum flow at the inlet. The inlet throttle control
can be electronically
controlled and electrically powered (e.g. via an electric motor), such that
the electric inlet valve
is adjusted in response to an input from a controller. The input from the
controller can be
modulated electrical power and/or a control signal. Control signals can be
derived from inputs to
the controller, such as when a pressure switch, sensor, or other input (e.g.,
from an operator)
identifies a predetermined pressure level, and adjusts the valve to allow a
different pressure level
in the compressor tank.
[0019] Conventional (i.e. pneumatic) systems are configured to maintain the
compressor at
full pressure, yet providing no output flow, when no output air is needed.
Operating in this mode,
however, consumes a high amount of power (i.e., requires significant fuel
consumption) as, even
though the pump is not pumping air for an output, the pump is spinning against
a high
differential pressure. The differential pressure is the case pressure (e.g.,
built up pressure within
the housing) of the compressor which is at the output set pressure (e.g..
about 150 pounds per
square inch (psi)), less the inlet to the pump which is at a near vacuum
(e.g., about -14 psi) when
the inlet valve is closed.
[0020] The systems and methods described herein provide an improvement to
conventional
pneumatic inlet valves by replacing the pneumatically controlled inlet valves
with an electrically
powered and controlled inlet valve.
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[0021] The electric inlet valve can be controlled by a controller (e.g., a
computer,
microprocessor, logic instructions. etc.). The controller is configured to
receive information
regarding pressure, temperature, airflow, and other feedback information from
the compressor,
as well as information from other sources, such as engine inputs (e.g., speed,
power, etc.),
operator inputs, etc. The controller analyzes and employs the information to
determine an output
signal to control the electric inlet valve (e.g., a position of the inlet
valve, amount of airflow
required, etc.). Thus, the controller controls the electric inlet valve to a
position as determined
(e.g., based on the information and the original position of the valve) via
one or more control
schemes, such as an open or closed feedback loop.
[0022] In disclosed examples, the electric inlet valve can be controlled by
analog circuits
and/or a variety of switching devices, such as pressure or other mechanical
switches. For
example, a variety of applications may not employ digital controls and/or
computational logic.
However, by employing an analog circuit and/or switching device that is
triggered in response to
one or more conditions (e.g., exceeding a threshold pressure, power, voltage,
and/or current
value), will similarly benefit from the electric inlet valve disclosed herein.
[0023] In some examples, based on a determination that the compressor is
not in use, the
controller controls the electric inlet valve to a closed position to stop
airflow into the compressor.
Further, the compressor can reduce internal case pressure via a bleed down
valve, and/or as an
integrated function of the electric inlet valve to reduce the standby load of
the compressor.
Additionally or alternatively, the compressor can be declutched and the engine
can be controlled
to idle in response to a determination that the compressor is not in use.
[0024] Electric control of the compressor inlet valve allows control of the
valve without the
need for pneumatic control, such as when no air pressure is present. The
electric inlet valve can
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therefore close before starting of the compressor to produce "softer" (i.e.
lower power) starts,
and to reduce wear on the compressor clutch. The compressor can operate at
relatively low
pressures, below what is needed when using a pneumatic valve control. The
controller can
maintain the electric inlet valve in a closed position even after the
compressor is shut off and
pressure is bled down, including when pressure levels in the compressor fall
below a level
required for pneumatic control. This prevents oil mist and/or fumes from
evacuating the
compressor case as the compressor blows down and/or cools down.
[0025] Electric control of the compressor inlet valve further allows the
operator to select
pressure via the controller (e.g., via a user interface, control panel, remote
system, etc.). The
controller controls the electric inlet valve to regulate airflow into the
pump, which produces the
selected/desired pressure and/or output flow at the outlet of the compressor.
Use of an electric
control allows an operator to make a selection for the controller by a system
remote from the
compressor (e.g., via a wired and/or wireless communications protocol).
[0026] Electric inlet valve can be controlled to regulate flow and or
pressure output of the
compressor to a higher or lower level to match a needed output for a selected
process, such as a
welding and/or a cutting process. For example, the pressure output can be
reduced and
maintained at a low pressure for plasma cutting or carbon arc cutting to
reduce power
consumption and match the air delivery needs of those processes. As disclosed
herein, the
controller can identify an operator process selection and dynamically adjust
the compressor
output accordingly. The electric control eliminates the need of an operator to
select the process
and then set the air pressure level, as the electronic control sets the
compressor to match the
selected process. The result is similar to an "Autoset" feature (e.g., as can
be found in MIG
machines) such that a single input into the controller determines the settings
of multiple machine
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parameters (e.g., on the power supply, welder, air compressor, load, etc.).
Thus, the resulting
process is simpler, requires fewer inputs from the operator, and avoids
operator error in
equipment setup.
[0027] To improve upon conventional designs, the disclosed electric inlet
valve allows the
controller to reduce power consumption and/or output of the compressor. For
example, when the
controller determines the engine and/or the motor powering the compressor has
a larger load than
the current operating capacity (e.g., based information from one or more
sensors, associated
systems, a user input, etc.), the electric inlet valve can be adjusted to
regulate the airflow in the
compressor. Such a condition may result from overloading, or to reduce
overheating in high
ambient temperatures. This configuration results in a compact, cost effective,
and reliable
system. with the compressor to be driven by the engine.
[0028] The system can be housed in an enclosure, the engine being a source
of mechanical
power, with the compressor utilizing that power to provide output in the form
of compressed air.
The mechanical power of the engine is transferred to the air compressor via a
clutch, belt, idler
pulley, compressor pulley, etc., which is directly connected to the engine
crankshaft. In some
examples, the engine is directly coupled to an electric generator to generate
electrical power.
[0029] The electric inlet valve can be located within the enclosure and/or
integrated with the
air compressor, such as in an inlet air path. For instance, the electric inlet
valve can be mounted
directly to an inlet of the screw housing, or it can be mounted separate from
the screw housing,
such as coupled to the system via a hose, a pipe, etc.
[0030] In disclosed examples, a variety of mechanical configurations of the
electric inlet
valve are possible. For instance, the electrically powered operating mechanism
could be a
poppet valve, a rotary valve, a spool valve, a pressure balanced valve, etc.
Further, to facilitate
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the activation and/or deactivation of the electric inlet valve, one or more of
the mechanical vales
can include a spring, a diaphragm, an orifice, a piston, among other
configurations.
[0031] In some examples, the air compressor is a rotary screw type
compressor driven by the
engine. A rotary screw compressor is a type of gas compressor that uses a
rotary type positive
displacement mechanism. They are used to replace piston compressors where
large volumes of
high-pressure air are needed, such as for construction or industrial
applications. The gas
compression process of a rotary screw is a continuous sweeping motion, so the
pressure build up
is generally smooth relative to a piston compressor. Additionally, rotary
screw compressors are
relatively compact and operate smoothly with limited vibration. Some rotary
screw compressors
are characterized as oil-injected, where lubricating oil aids in sealing and
cooling functions.
[0032] In disclosed examples, an air compressor control system includes an
electric inlet
valve configured to regulate airflow of an air compressor based on a position
of the electric inlet
valve, and a controller configured to adjust a position of the electric inlet
valve via an electrical
control signal. In some examples, a sensor is configured to measure one or
more characteristics
of the air compressor. In examples, the sensor is a pressure sensor having an
adjustable pressure
range.
[0033] In examples, a user interface configured to select a pressure level
to the controller. In
some examples, the controller is configured to receive a selected pressure
level for the air
compressor from the user interface, receive a signal corresponding to a
measured pressure level
of the air compressor from the sensor, compare the selected pressure level to
the measured
pressure level, and calculate a pressure difference based on the comparison.
In examples, an
electrically controlled and powered motor configured to adjust a position of
the electric inlet
valve, wherein the controller is configured to determine a position of the
electric inlet valve;
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calculate a change in position of the electric inlet valve based on the
pressure difference; and
control the motor to adjust the position of the electric inlet valve based on
the calculated change
in position.
[0034] In disclosed examples, an air compressor control system includes a
user interface
configured to receive a command from an operator; a sensor configured to
measure one or more
characteristics of the system; an electric inlet valve integrated within an
air compressor and
configured to regulate airflow of the air compressor based on a position of
the electric inlet
valve; and a controller configured to adjust a position of the electric inlet
valve via an electrical
control signal in response to a command from the user interface or a
measurement from the
sensor.
[0035] In some examples, the controller is configured to automatically
determine a desired
pressure level in the air compressor based on the command or the measurement.
In examples, the
command corresponds to a gouging or plasma cutting operation. In some
examples, the
controller is configured to: receive a selected gouging or plasma cutting
operation from the user
interface; determine a desired air pressure for the air compressor based on
the selected operation;
compare the desired air pressure level to a measured air pressure level; and
calculate a pressure
difference based on the comparison.
[0036] In examples. a motor configured to adjust a position of the electric
inlet valve,
wherein the controller is configured to: determine a position of the electric
inlet valve; calculate
a change in position of the electric inlet valve based on the pressure
difference; and control the
motor to adjust the position of the electric inlet valve based on the
calculated change in position.
In some examples, the sensor is a pressure sensor having an adjustable
pressure range.
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[0037] In disclosed examples, a method of controlling an air compressor
includes measuring,
by a sensor, a pressure at an inlet or an outlet of the air compressor; and
adjusting a position of
an electric inlet valve via an electrically powered mechanism to regulate
airflow of the air
compressor in response to an electrical control signal.
[0038] In some examples, the method further includes receiving, at the
controller, a pressure
level selection from a user interface. In some examples, the method further
includes receiving a
signal corresponding to a measured pressure level of the air compressor from
the sensor. In
some examples, the method further includes comparing the selected pressure
level to the
measured pressure level; and calculating a pressure difference based on the
comparison.
[0039] In some examples, the method further includes determining, by the
controller, a
position of the electric inlet valve; and calculating, by the controller, a
change in position of the
electric inlet valve based on the pressure difference. In some examples, the
electrically powered
mechanism is a motor, the method further includes controlling the motor to
adjust the position of
the electric inlet valve based the calculated change in position.
[0040] In some examples, the sensor is a pressure sensor having an
adjustable pressure
range. In some examples, the method further includes shutting off the air
compressor; and
controlling the motor to maintain the electric inlet valve in a closed
position to prevent oil mist
and/or fumes from evacuating the compressor case as the air compressor cools
down.
[0041] In disclosed examples, an engine driven power system includes a
power supply; an air
compressor comprising an electric inlet valve; and a controller configured to
receive an input
corresponding to one or more parameters associated with the power supply or
the air compressor,
and generate one or more electrical control signals to regulate an output of
the power supply and
to regulate airflow of the air compressor in response to the input.
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[0042] In some examples, the input corresponds to a single input that
provides a plurality of
parameter settings for the power supply and the air compressor. In examples,
the input
corresponds to a gouging or plasma cutting operation. In some examples, a
sensor to measure a
pressure at an inlet or an outlet of the air compressor.
[0043] In some examples, the controller is configured to receive a signal
corresponding to a
measured pressure level of the air compressor from the sensor; compare the
selected pressure
level to the measured pressure level; and calculate a pressure difference
based on the
comparison. In examples, the controller is further configured to determine a
position of the
electric inlet valve; and calculate a change in position of the electric inlet
valve based on the
pressure difference.
[0044] In examples, the electrically powered mechanism is a motor, the
controller further
configured to control the motor to adjust the position of the electric inlet
valve based the
calculated change in position. In some examples, the controller is configured
to command the air
compressor to shut off; and to control the motor to maintain the electric
inlet valve in a closed
position to prevent oil mist and/or fumes from evacuating the compressor case
as the air
compressor cools down.
[0045] Advantages of the present disclosed methods and apparatuses include
the elimination
of pneumatic control lines, which are prone to freezing when exposed to cold
temperatures. The
system allows operators to set pressure from an electronic user interface,
which can be a remote
pressure adjustment control. Further, expensive pneumatic control components
and heater
systems are reduced and/or eliminated by implementation of the electronic
control systems.
[0046] The use of a controller and electronic components allows for receipt
and analysis of
multiple feedback parameters (e.g., pressure at the electric inlet valve,
outlet valve, within the
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compressor case; engine speed; power output characteristics such as voltage,
current; system
temperature; etc.) and operates the air compressor in different modes more
easily than a
conventional, mechanical control (e.g., standby mode, low power mode, startup
mode, idle
mode, etc.).
[0047] As used herein, the term "welding-type power" refers to power
suitable for welding,
plasma cutting, induction heating. CAC-A and/or hot wire welding/preheating
(including laser
welding and laser cladding). As used herein, the term -welding-type power
supply" refers to any
device capable of, when power is applied thereto, supplying welding, plasma
cutting, induction
heating, CAC-A and/or hot wire welding/preheating (including laser welding and
laser cladding)
power, including but not limited to inverters, converters, resonant power
supplies, quasi-resonant
power supplies, and the like, as well as control circuitry and other ancillary
circuitry associated
therewith.
[0048] As used herein, a "circuit" includes any analog and/or digital
components, power
and/or control elements, such as a microprocessor, digital signal processor
(DSP), software, and
the like, discrete and/or integrated components, or portions and/or
combinations thereof.
[0049] As used herein, the terms "first" and "second" may be used to
enumerate different
components or elements of the same type, and do not necessarily imply any
particular order. For
example, while in some examples a first compartment is located prior to a
second compartment
in an airflow path, the terms "first compartment" and "second compartment" do
not imply any
specific order in which airflows through the compartments.
[0050] FIG. 1 is a functional diagram of an example power system 100. The
system 100 is
an engine-driven power system, which includes an engine 104 that drives an air
compressor 102
(e.g., a rotary screw type air compressor). The air compressor 102 is driven
by the engine 104 via
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a clutch 106. The air compressor 102 can include one or more sensors 108 to
sense and/or
measure a pressure at one or more locations within the system. Sensors 108 can
also be used to
directly and/or indirectly measure variables such as airflow, changes in
temperature, forces
acting on housings, among others. The sensors 108 can be any type of sensor
configured to
measure a pressure, including analog and digital sensors, force collector type
sensors such as
piezo-resistive strain gauge. piezoelectric, optical fiber based sensors,
potentiometric thermal
sensors, transducers, pressure indicators, piezometers, manometers, to name
but a few.
[0051] In the example of FIG. 1, the sensor 108 measures pressure(s) within
a housing/tank
of the air compressor 102, at an outlet, an inlet, and/or another location of
the air compressor
102. A motor and/or solenoid 110 is configured to control an electrically
controlled compressor
inlet valve 111 and to adjust pressure in the compressor case from the
electric inlet valve 111. In
examples, a controller 114 is configured to monitor and/or control one or more
conditions of the
system 100. For instance, the controller 114 receives information from the
sensor 108, as well as
other operating parameters (e.g., temperature, rotation speed of one or both
of the compressor
102 and engine 104, etc.) of the system 100.
[0052] In some examples, an electrical generator 120 is connected to the
engine 104 to
provide one or more types of electrical power suitable for specific and/or
general purpose uses,
such as welding-type power, 110 VAC and/or 220 VAC power, battery charging
power, and/or
any other type of electrical power. The input and output characteristics of
the generator 120 (e.g.,
voltage, current, power, rotational speed, etc.) can be provided to the
controller 114 to determine
if and how much adjustment to the inlet valve 11 is needed. Furthermore, the
example system
100 may include other components not specifically discussed herein.
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[0053] In some examples, the system 100 employs a controller 114 for
controlling an output
of the air compressor 102. For instance, the controller 114 can engage the
clutch 106 to operate
at variable speeds in response to the speed of the engine 104, operate one or
more valves to
release pressure from the air compressor 102, as well as controlling the
engine 114 to idle, such
as when the compressor 102 is not in use. Additionally or alternatively, a
user interface 118 can
be employed to allow a system operator to adjust one or more parameters
associated with the
system 100. For example, one or more predetermined pressure levels and/or
ranges can be
adjusted via the user interface 114 to accommodate a particular operation or
need. The user
interface 118 can be integrated with and/or located remotely from the air
compressor 102 and/or
the controller 114.
[0054] In other examples, an operation of the welding system 100 can be
selected (e.g., via
user interface 118) or automatically determined by the controller 114 based on
an analysis of
received data (e.g., via sensor 108). The electrical control system enables
the use of an
"AutoSet" feature, such that the engine driven unit can coordinate with the
air compressor output
pressure. Thus, a change in process and/or output requirements can set or
command an
adjustment in the air compressor in response to the change of process and/or
selection. In other
words, a single input from the operator produces setup parameters for the
welding system and the
compressor. The result is a more responsive, faster acting air compressor,
which provides more
precise control of the compressor outlet than conventional systems are capable
of.
[0055] The controller 114 is able to receive and analyze multiple
parameters associated with
the air compressor 102 or they system 100 (e.g., pressure at the electric
inlet valve 111, outlet
valve 116, within the compressor case; speed of the engine 104; power output
characteristics
such as voltage, current; system temperature; etc.) and operates the air
compressor 102 in
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different modes more easily than a conventional, mechanical control (e.g.,
standby mode, low
power mode, startup mode, idle mode, variable pressure, etc.). Thus, a more
informed analysis is
conducted in determining the proper valve adjustment.
[0056] In response to a process selection, the controller 114 can
dynamically control a
position of the electric inlet valve 111 to adjust the amount of airflow
through the compressor
inlet. In this manner, the controller 114 automatically sets the pressure
(e.g., via the "Autoset"
feature) to provide airflow as needed for a particular operation (e.g.,
cutting, gouging, welding,
etc.).
[0057] Additionally or alternatively, the controller 114 can command the
air compressor 102
or the engine 104 to change mode (e.g., standby, idle, full operational speed,
etc.) based on the
received and analyzed data. For instance, if the system 100 is set for a
plasma cutting operation,
the air compressor 102 may require an increase in air pressure. Thus, the
controller 114 will
adjust the electric inlet valve to increase the air pressure.
[0058] Conversely, if the system 100 is powered down, the controller 114
can institute one or
more procedures to shut down one or more components of the system. For
example, the
controller 114 can maintain the electric inlet valve 111 in a closed position
even after the air
compressor 102 is shut off and pressure is bleed down. This prevents oil mist
and/or fumes from
evacuating the compressor case as the air compressor 102 cools down and/or
blows down.
[0059] In some examples, the sensor 108 is one or more transducers 112
configured to
measure a pressure level one or more locations of the air compressor (e.g., at
an outlet, at a
housing, at the inlet, etc.). The transducer 112can transmit the information
to the controller
114via a signal indicating the pressure level to the controller 114 via one or
more circuits. The
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controller 114 can be configured to control the electric inlet valve 111, to
activate in response to
a change in the measured or selected pressure level.
[0060] Further, the controller 114 can control the clutch 106 to disengage
in response to the
second pressure level being below a second, low-pressure level. In this
example, the sensor 108
is able to sense the pressure at multiple locations, such as by alternating
measurements, and the
controller 114 is capable of analyzing the signals from the sensor 108 to
determine the
appropriate control.
[0061] Additionally or alternatively, the system 100 includes a timer, such
as a countdown
timer or other suitable timing device (e.g., incorporated with a
microprocessor, etc.), configured
to activate in response to a high-pressure level being sensed by the sensor
108. Simultaneously
or in response to the closure of the electric inlet valve 111, the timer
counts down a
predetermined duration (e.g., between about 30 seconds and 2 minutes), which,
upon expiry, can
inform the controller 114 to disengage the clutch 106. Before disengaging the
clutch 106, the
controller 114 determines if the pressure level has reset (e.g., the sensor
108 no longer senses the
high-pressure level). Thus, the timer is reset each time the sensor 108
indicates the high-pressure
condition is no longer present.
[0062] In examples, when a pre-determined pressure level is reached (e.g.,
150 psi), the
controller 114 activates the electric inlet valve 111. The electric inlet
valve 111 closes to stop
the compressor 102 from pumping air.
[0063] In some examples, the controller 114 is configured to sense or
receive information
indicating that the air output has not been used, and proceeds to idle the
engine 104 based on the
information. The controller 114 responds to the low-pressure in the compressor
case. Once the
low-pressure level is met in the compressor case, the clutch 106 to disengages
in response.
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[0064] The clutch 106 disengages and an electrical signal from the
controller 114 can be
used to direct the engine 104 to enter into an idle mode. In examples where no
load is on the
engine 104, the engine 104 can idle with a fixed engine throttle position idle
system at a
consistent and predictable speed. With the clutch 106 disengaged, the
compressor 102 enters into
a stand-by mode. For instance, stand-by mode corresponds to the outlet
pressure being
maintained via the outlet valve 116 while the compressor 102 is at low or no
pressure and
disconnected from the engine 104. The compressor 102 is still on and restarts
when air pressure
at the outlet is reduced to a predetermined pressure level.
[0065] When air is used (e.g., to operate an air drive tool), the
compressor 102 responds by
starting to pump air again. In response, the compressor clutch 106 engages and
the electrically
controlled compressor inlet valve 111 opens, allowing air into the now turning
pump within the
compressor 102. Additionally or alternatively, the controller 114 is designed
to re-start the
compressor 102 from a stand-by mode, which is an improvement over conventional
compressor
control schemes.
[0066] FIG. 2 illustrates an example control 200 for an air compressor, in
accordance with
the present disclosure. As shown in FIG. 2, an inlet filter 202 is connected
to an electric inlet
valve 211 to allow air to flow into the compressor. A blowdown valve 206 is
connected to a
blowdown orifice 208. A pressure transducer 214 is configured to measure a
pressure level of
the compressor. A minimum pressure control valve 216 incorporates a check
valve to maintain
pressure downstream during blowdown of the compressor case. The pressure
transducer 214 is
placed after the minimum pressure/check valve 216 to measure the output
pressure of the
compressor. The inlet valve 211 is configured to open, close, or modulate air
flow in response to
a change from the pressure transducer 214. For example, a controller (e.g.,
the controller 114)
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can receive and analyze signals from one or more components (e.g., the
pressure transducer 214)
and generate a command signal to control operation of the electric inlet valve
202, for instance.
[0067] The blowdown valve 206 is configured to open in response to the
pressure transducer
214 sensing a pressure above a predetermined threshold level, a duration of no
output (e.g., a
time delay), a low pressure switch 412, or another means of determining the
air compressor is
not in use. Once activated/opened, the blowdown valve 206 releases air from
the compressor
case. For instance, once pressure transducer 214 senses a predetermined
pressure level, the
electric inlet valve 211 is closed and the blowdown valve 206 is opened to
provide a timed
pressure reduction of the compressor case until the pressure transducer 214 no
longer senses the
pressure level above the predetermined threshold level.
[0068] A second, low-pressure switch 412 may be configured to sense a
second, low-
pressure level in the compressor case, which can in response control a clutch
(e.g. clutch 106) to
disengage from an engine (e.g., engine 104). In particular, as the compressor
case bleeds down
and the pressure reduces to a predetermined level (e.g., 30 psi), the low-
pressure switch 412
deactivates/opens which disengages the compressor clutch. The clutch
disengages, which can
also indicate that the engine is to enter into an idle mode.
[0069] If the pressure at the pressure transducer 214 senses a pressure
below the
predetermined threshold level, the controller closes the blowdown valve 206
and opens the
electric inlet valve 211. The clutch can also be engaged, such that the engine
is capable of
turning the air compressor to increase pressure within the housing.
[0070] Additionally or alternatively, the control 200 can include a
pressure relief valve 418
as a safety outlet, pressure gauge 220, and an over pressure switch 210. For
example, when a
pressure exceeds a predetermined level, an over pressure switch 210 activates
which disengages
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the compressor clutch. A case temperature sensor 222 can also provide
information regarding a
temperature in the air compressor. In some examples, the control circuit 200
may implement
and/or be integrated into the controller 114 of FIG. 1. In some examples, the
control circuit 200
is a wholly separate controller configured to respond to changes in pressure
and control the
system components. The example circuit 200 responds to changes in the pressure
level at the
compressor 102 and controls the electric inlet valve 111 accordingly.
[0071] FIG. 3 is a diagram of an example air compressor 302 with an
exploded view of an
electrically powered and controlled inlet valve 311, in accordance with
aspects of this disclosure.
In the example of FIG. 3, the electrically controlled inlet valve 311 includes
one or more
components to regulate flow of air into the air compressor 302. The components
can include a
conical spring 1, 0-rings 2, 3, and a valve disk with 0-ring and rod 4.
Additionally, a motor 310
is included to adjust a position of the electrically controlled inlet valve
311, as described with
respect to FIGS. 1 and 2. Thus, motor 310 (e.g., such as motor and/or solenoid
110) can receive
commands from a controller (e.g., controller 114) to adjust the position of
the electrically
controlled inlet valve 311 in order to provide the desired pressure level.
[0072] FIG. 4 is a diagram of another example air compressor 402 with an
exploded view of
an electrically powered and controlled inlet valve 411, in accordance with
aspects of this
disclosure. In the example of FIG. 4, the electrically controlled inlet valve
411 includes one or
more components to regulate flow of air into the air compressor 402. The
components can
include a conical spring 1, hex-nut 2, conical spring 3, piston 4, V-ring 5, 0-
rings 6, 7, lock
washer 8, plate set 9, 0-ring 10, and rod 11. Additionally, a motor 410 (e.g.,
such as motor
and/or solenoid 110) is included to adjust a position of the electrically
controlled inlet valve 311,
as described with respect to FIGS. 1 and 2. Thus, motor 410 can receive
commands from a
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controller (e.g., controller 114) to adjust the position of the electrically
controlled inlet valve 411
in order to provide the desired pressure level.
[0073] FIG. 5 is a flowchart illustrating example method 500 of controlling
an engine driven
air compressor, as described with respect to FIGS. 1 and 2. In block 502, a
sensor (e.g., the
sensor 108) measures a pressure at an inlet or an outlet (e.g., the outlet
116) of the air compressor
(e.g., the air compressor 102). In block 504, a controller (e.g.. controller
114) receives a signal
corresponding to a measured pressure level of the air compressor from the
sensor.
[0074] At block 506, the controller receives a pressure level selection
from a user interface
(e.g., user interface 118). At block 508, the controller compares the selected
pressure level to the
measured pressure level. At block 510, the controller calculates a pressure
difference based on
the comparison.
[0075] At block 512, the controller determines a position of an electric
inlet valve (e.g.,
electric inlet valve 111). At block 514, the controller calculates a change in
position of the
electric inlet valve based on the pressure difference. At block 516, the
controller generates an
electrical control signal based on the calculated change in position. At block
518, the controller
adjusts a position of an electric inlet valve via a motor (e.g., motor 110) to
regulate airflow of the
air compressor based on the electrical control signal. The process then
returns to block 502 to
continue monitoring and measuring a pressure of the air compressor.
[0076] Additionally or alternatively, method 500 of FIG. 5 may be
implemented by the
controller 114 of FIG. 1 by executing machine-readable instructions, such as
stored on a non-
transitory machine-readable storage device. In such an examples, the
controller 114 can receive
electronic signals from the system sensors (e.g., sensor 108, transducer 112,
or other system
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sensors) and control the system components (e.g., electric inlet valve 111)
based on a series of
algorithms and/or calculations consistent with the examples provided herein.
[0077] As utilized herein,"and/or means any one or more of the items in the
list joined by
"and/or". As an example,"x and/or y" means any element of the three-element
set {(x), (y), (x,
y)). In other words,"x and/or y" means"one or both of x and y". As another
example,"x, y,
and/or z" means any element of the seven-element set 1(x), (y), (z), (x, y),
(x, z), (y, z), (x, y, z)}.
In other words,"x, y and/or z" means"one or more of x, y and z". As utilized
herein, the term
"exemplary" means serving as a non-limiting example, instance, or
illustration. As utilized
herein, the terms"e.g.," and"for example" set off lists of one or more non-
limiting examples,
instances, or illustrations.
[0078] While the present method and/or system has been described with
reference to certain
implementations, it will be understood by those skilled in the art that
various changes may be
made and may be substituted without departing from the scope of the present
method and/or
system. In addition, many modifications may be made to adapt a particular
situation or material to
the teachings of the present disclosure without departing from its scope. For
example, systems,
blocks, and/or other components of disclosed examples may be combined,
divided, re- arranged,
and/or otherwise modified. Therefore, the present method and/or system are not
limited to the
particular implementations disclosed. Instead, the present method and/or
system will include all
implementations falling within the scope of the appended claims.
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Date Recue/Date Received 2021-09-29
