U.S. patent application number 11/491552 was filed with the patent office on 2007-08-02 for integral sensor and control for dry run and flow fault protection of a pump.
Invention is credited to Jeff Cain, John Fong, James C. Walls.
Application Number | 20070177985 11/491552 |
Document ID | / |
Family ID | 38322263 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070177985 |
Kind Code |
A1 |
Walls; James C. ; et
al. |
August 2, 2007 |
Integral sensor and control for dry run and flow fault protection
of a pump
Abstract
A pump providing fault protection based on a controller
receiving sensed pressure values from a pressure sensor included in
a cavity of the pump, so as to be integral with the pump.
Inventors: |
Walls; James C.; (Mission
Viejo, CA) ; Cain; Jeff; (Tucson, AZ) ; Fong;
John; (Lake Forest, CA) |
Correspondence
Address: |
WARE FRESSOLA VAN DER SLUYS &ADOLPHSON, LLP
BRADFORD GREEN, BUILDING 5
755 MAIN STREET, P O BOX 224
MONROE
CT
06468
US
|
Family ID: |
38322263 |
Appl. No.: |
11/491552 |
Filed: |
July 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60701607 |
Jul 21, 2005 |
|
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Current U.S.
Class: |
417/44.2 |
Current CPC
Class: |
F04B 49/10 20130101;
F04B 49/022 20130101; F04B 2205/04 20130101; F04B 49/06 20130101;
F04B 2205/02 20130101; F04B 43/0081 20130101 |
Class at
Publication: |
417/044.2 |
International
Class: |
F04B 49/06 20060101
F04B049/06 |
Claims
1. A pump system, comprising: a pressure sensor, for providing a
signal indicative of a sensed pressure; a controller, responsive to
the signal indicative of a sensed pressure, and also responsive to
electrical power, for regulating the electrical power based on at
least the sensed pressure; and a pump unit, having a pumping
mechanism and an electrical motor for driving the pumping
mechanism, responsive to the regulated electrical power; wherein
the pumping mechanism includes an inlet cavity and an outlet cavity
on either side of a pumping structure, and the pressure sensor is
disposed in the inlet cavity and/or the outlet of the pumping
mechanism and is communicatively coupled to the controller.
2. A pump system as in claim 1, wherein the controller uses one or
more control parameters that are monitored for protecting the pump
unit from one or more fault conditions, and the controller is
programmable to provide a different response for different values
or different value trends of the one or more control
parameters.
3. A pump system as in claim 2, wherein the one or more control
parameters include the sensed pressure.
4. A pump system as in claim 2, wherein the one or more control
parameters include the sensed pressure and electrical current for
the electric motor.
5. A pump system, comprising: a pressure sensor, for providing a
signal indicative of a sensed pressure; means, responsive to the
signal indicative of a sensed pressure, and also responsive to
electrical power, for regulating the electrical power based on at
least the sensed pressure; and a pump unit, having a pumping
mechanism and an electrical motor for driving the pumping
mechanism, responsive to the regulated electrical power; wherein
the pumping mechanism includes an inlet cavity and an outlet cavity
on either side of a pumping structure, and the pressure sensor is
disposed in the inlet cavity and/or the outlet of the pumping
mechanism and is communicatively coupled to the controller.
6. A pump system as in claim 5, wherein the means for regulating
electrical power uses one or more control parameters that are
monitored for protecting the pump unit from one or more fault
conditions, and is programmable to provide a different response for
different values of the one or more control parameters.
7. A method, comprising: sensing pressure at either an inlet cavity
or an outlet of a pumping mechanism of a pump unit having an
electrical motor; and regulating electrical power to the electrical
motor based on at least the sensed pressure.
8. A method as in claim 7, further comprising monitoring one or
more control parameters and using the monitored values for
protecting the pump unit from one or more fault conditions.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] Reference is made to and priority claimed from U.S.
provisional application Ser. No. 60/701,607 filed Jul. 21,
2005.
FIELD OF THE INVENTION
[0002] The present invention relates to a pump, and more
particularly to a controller or device built into a pump for
providing protection for the pump against dry run and flow fault
conditions.
BACKGROUND OF THE INVENTION
[0003] Existing pump control devices for providing protection for a
smaller-sized water pump against dry run and flow fault conditions
typically include a pressure-activated electrical switch that turns
off power to the pump when the monitored pressure is too low (or is
a vacuum). The pressure-activated switch is installed externally to
the pump, in such a way as to monitor the inlet and/or outlet
pressure. The control is reflexive, in that a drop in pressure
below the threshold of the pressure-activated switch will cause the
switch to operate. The pressure-activated switch is typically
mechanical or electro-mechanical in construction.
[0004] The pressure sensing components for such pump control
devices are typically inserted into the plumbing lines leading into
and/or out of the pump. A common method consists in inserting a
vacuum-sensing switch into the plumbing line on the supply side of
the pump. This creates a risk of leaks in the plumbing, increases
the work required for installation, and adds to the physical
component count.
[0005] In addition, such pump control devices typically lack input
and decision-making flexibility in that they are designed to
respond to a single-variable input stimulus (pressure), and they
typically lack variable output functionality since they can only
switch the pump to an ON or OFF state. This can be problematic if
conditions on the sensed side of the pump are within acceptable
operating limits, but conditions on the other side are not. For
example, if a pump control device is configured only to respond to
vacuum conditions appearing on the supply side of a pump, then no
protection is afforded against uncontrolled flows resulting from
catastrophic failure of, or damage to, the plumbing system charged
by the pump.
SUMMARY
[0006] The invention provides a pump having integral dry run and
flow fault protection via a controller using a pressure sensor
embedded in either the inlet or outlet cavity of the pump, and the
method of operation of the controller. The controller operation is
based on the sensed pressure as well as possibly other control
parameters that are monitored for protecting the pump from one or
more fault conditions. The controller is programmable so that the
value, interpretation and response associated with the values of
the one or more control parameters--or with trends in the values of
the one or more control parameters--may be set and/or changed based
on a desired operational performance for the pump.
[0007] The one or more control parameters may include the outlet
pressure of the pump, as well as any number of conceivable
additional system parameters or control inputs in order to suit the
particulars of a given application system or context, such as the
inlet pressure, internal or external temperatures, external
operational mode signals, supply voltage, electrical current,
override commands, emergency shutdown commands, motor RPM, and so
on.
[0008] A method of operation of the controller may include one or
more steps run as a computer program on a computer processor or
other suitable processing device or module that forms part of the
controller. Thus, all or part of the operation of a controller
according to the invention may be encoded as instructions for
execution by a processor, and the instructions may be stored on a
storage medium where the processor can execute the instructions
such as read-only memory (ROM) or re-writeable program memory such
as FLASH. Therefore, the invention also provides a computer program
product, i.e. the computer program instructions and the storage
medium holding the instructions.
[0009] Alternatively, the logic according to which the controller
operates can be encoded and provided as one or more application
specific integrated circuits (ASICs). As a further alternative, the
full logic by which the controller operates can be provided by a
combination of stored computer programs and one or more ASICs.
[0010] In operation, the invention uses a microcontroller (MCU),
and one or more computer programs, a pressure sensor integral to
the pump, and electrical or electronic power switching components.
As such, the invention does not require components external to the
pump, nor does it require intrusions into the inlet or outlet
plumbing lines, thus avoiding the risk of damage to the plumbing
caused by inserting the pressure sensor into the plumbing line, and
thus also avoiding the associated burdens of parts and
installation.
[0011] However the logic of operation is provided, either via
computer programs used by a microcontroller or via ASICs or both,
the pump controller operation is interpretive and dynamic and can
provide optimized behavior unique to a given application, i.e. the
complex logic allows transcending first-order reflexive response
behavior. The computer program parameters can be set such that any
desired threshold of low pressure, alone or in combination with
other monitored parameters, can trigger a corresponding desired
response. For example, the pump controller can combine electrical
current data with pressure data over time, and then calculate a
threat index which in turn is used as a basis for response to the
sensed current and pressure data. In particular for example, the
pump controller logic can be tailored to incorporate fixed or
variable time delays, to operate the pump at single or multiple
reduced or increased power levels, to attempt resumption of
operation based on any number of decision criteria, to observe
configurable discretion and response criteria set at the time of
manufacture or in the field, and so on.
[0012] As is known, unusually large fluid flows in a plumbing
system may result from failure or damage to the plumbing system.
Such "flow faults" (analogous to excessively large electrical
current flow in an "electrical fault") can cause the pressure of
the fluid in the system served by the pump to fall to a low value.
The pump controller can be configured (via the computer programs or
ASICs) to disregard flow fault pressures, or to act on them in a
protective response in conjunction with any of various decision
approaches. Thus, the invention not only can protect against dry
run conditions (where there is no fluid remaining to be supplied to
the fluid system), but also against undesired, unusually large flow
conditions, i.e. flow faults.
[0013] An illustrative application of the invention is for a
Bag-in-Box beverage syrup dispensing system, where beverage syrups
are stored in non-pressurized bags. The syrup is pumped from the
bags upon demand, such as to fill a drink container. When the bag
is emptied, the described invention senses the drop in system
pressure via the integral pressure sensor in the pump, stopping the
pump after a pre-determined service time, thus avoiding further
operation of the pump sans syrup. Alternatively, an integral
pressure sensor can be configured such that it senses vacuum at the
pump inlet and/or differential pressure between the inlet and
outlet, depending on the particular characteristics of a target
system that need be served. The invention may also sense and factor
changes in electrical current delivered to the pump motor as
electrical current drawn by the pump motor often drops considerably
upon depletion of the fluid supply. Finally, the invention can be
realized in such a way that the low pressures resulting from flow
faults can result in a protective response, such as pump
shutdown.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other objects, features and advantages of the
invention will become apparent from a consideration of the
subsequent detailed description presented in connection with
accompanying drawings, in which:
[0015] FIG. 1 is a block diagram/ schematic of an integral pump
control typical system diagram according to the present
invention.
[0016] FIG. 2 shows an operational flowchart of the steps of
operation of a pump controller according to the invention.
DETAILED DESCRIPTION
FIG. 1
[0017] FIG. 1 shows a pump system 10 according to the invention,
for pumping a fluid. It includes a pump control module (PCM) 15
serving as a controller for a pump electric motor 16, built into or
attached to the pump. An electrical power source 13 (AC or DC), is
connected to the PCM 15 by an electrical connection 14.
[0018] The pump system includes a pumping mechanism 18 driven by
the pump motor 16 and installed in a plumbing line, so as to have
inlet plumbing 11 and outlet plumbing 12. The pumping mechanism
includes an inlet cavity and an outlet cavity, and a structure (not
shown) such as valve chambers in a positive displacement diaphragm
pump, located between the two cavities and driven by the electric
motor in a cyclical pattern so as to give rise to a pumping action.
A pressure sensor 19 is built into the inlet and/or outlet cavity,
and communicatively coupled to the PCM so as to provide to the PCM
signals indicative of the fluid pressure in the (inlet or outlet)
cavity. The PCM uses the sensor signals to regulate power to the
electric motor, i.e. to turn on or off the power to the pump, or to
provide more or less electric power to the motor (e.g. by applying
more or less voltage to the motor).
[0019] In some embodiments, the PCM 15 is programmable, i.e. it
includes an embedded digital computing device, such as a
microcontroller or microprocessor, that is able to read a computer
program and/or data stored on a non-volatile storage medium or it
includes one or more ASICs and/or programmable control parameters,
by which operation of the PCM can be configured as desired, and in
particular, in case of additional sensed values (e.g. temperature,
or current to the motor) provided by other sensors, to provide more
than reflexive response to the sensed pressure.
[0020] In illustrative operation, in some embodiments the PCM 15
monitors the (inlet or outlet) cavity pressure of the pump over
time, reaching decision points and action responses based on
operational assumptions, and/or pre-determined criteria, and/or
adaptive learning behaviors, utilized individually or in
combination, as configured by computer program(s) and/or the logic
functions configured into ASICs. The PCM then acts to regulate
power to the motor pump via power control electronics, which may
include such common devices as transistors or thyristors (TRIAC,
SCR, etc.).
[0021] The PCM 15 may also monitor and factor into the decision and
response process any number of conceivable additional system
parameters or control inputs in order to suit the particulars of a
given application system or context, such as the inlet pressure,
internal or external temperatures, external operational mode
signals, supply voltage, electrical supply current, override
commands, emergency shutdown commands, motor RPM, and so on.
[0022] In addition to regulating power to the pump motor 16, the
PCM 15 may provide standard or application-specific external alerts
(visual alerts, audible alerts, etc.), and a user interface (e.g. a
video display) or other hardware (illuminating devices or audio
devices) may be provided to enable providing the alerts.
FIG. 2
[0023] FIG. 2 illustrates operation of the pump system 10 shown in
FIG. 1, beginning with a step 21 to initialize the PCM. Next, there
is a step 22 to monitor selected parameters such as pressure,
current and/or other parameters over time. This monitoring can be
continues. Then there is a step 23 to perform analog and/or digital
signal processing to determine conditioned digital values for the
sensed parameters. Then there is a step 24 to compute one or more
fault index value(s), i.e. to compute an indicator of whether to
shut down or change operational modes, then a step 25 to determine
if a fault condition criteria is met (per the computed fault index
value(s), by comparison to predetermined threshold value), a step
26 to perform a fault response, such as shut down, if the fault
condition criteria is met, and alternatively, if the fault
condition criteria is not met, a step 27 to update the operational
mode, and a step 28 to update outputs. Logical control is then
returned to the step 22 of monitoring pressure.
Possible Applications
[0024] By way of illustration, the invention can be applied to the
control of: pressurized water system pumps, such as found in
potable and non-potable water systems in vehicles, vessels,
structures and modular or mobile platforms; and pressurized fluid
system pumps, such as found in beverage dispensers or commercial
and industrial fluid systems.
CONCLUSION
[0025] It is to be understood that the above-described arrangements
are only illustrative of the application of the principles of the
present invention. Numerous modifications and alternative
arrangements may be devised by those skilled in the art without
departing from the scope of the present invention, and the appended
claims are intended to cover such modifications and
arrangements.
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