U.S. patent application number 10/028730 was filed with the patent office on 2003-04-24 for compressor protection module and system and method incorporating same.
Invention is credited to Collins, Michael, D'Aversa, Richard, O'Brien, Michael J..
Application Number | 20030077179 10/028730 |
Document ID | / |
Family ID | 21845097 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030077179 |
Kind Code |
A1 |
Collins, Michael ; et
al. |
April 24, 2003 |
Compressor protection module and system and method incorporating
same
Abstract
An apparatus for monitoring a compressor includes a plurality of
sensor inputs for receiving input regarding operating parameters of
a compressor, at least one control action output for sending a
control action to the compressor; and a control member communicated
with the plurality of sensor inputs and the control action output,
the control member being adapted to analyze input from the
plurality of sensor inputs, to determine a control action based
upon the input and to send the control action to the at least one
control action output.
Inventors: |
Collins, Michael; (Syracuse,
NY) ; D'Aversa, Richard; (Manassas, VA) ;
O'Brien, Michael J.; (Fort Wayne, IN) |
Correspondence
Address: |
George A. Coury
BACHMAN & LaPOINTE, P.C.
Suite 1201
900 Chapel Street
New Haven
CT
06510-2802
US
|
Family ID: |
21845097 |
Appl. No.: |
10/028730 |
Filed: |
October 19, 2001 |
Current U.S.
Class: |
417/63 |
Current CPC
Class: |
F04B 2205/10 20130101;
F04C 28/28 20130101; F04B 2205/04 20130101; F04B 2205/05 20130101;
F04B 2205/11 20130101; F04B 2201/0404 20130101; F04B 49/065
20130101; F04B 2205/01 20130101; F04B 2201/1212 20130101 |
Class at
Publication: |
417/63 |
International
Class: |
F04B 049/00 |
Claims
What is claimed:
1. An apparatus for monitoring a compressor, comprising: a
plurality of sensor inputs for receiving input regarding operating
parameters of a compressor; at least one control action output for
sending a control action to said compressor; and a control member
communicated with said plurality of sensor inputs and said control
action output, said control member being adapted to analyze input
from said plurality of sensor inputs, to determine a control action
based upon said input and to send said control action to said at
least one control action output.
2. The apparatus of claim 1, wherein said control member is adapted
to receive input comprising compressor discharge pressure,
compressor discharge temperature, compressor suction pressure,
compressor suction temperature, oil pressure and a compressor
on/off input signal.
3. The apparatus of claim 2, wherein said control member includes a
memory storing a plurality of potential control actions, a
plurality of adjustable operating parameters and a plurality of
sensor input value combinations corresponding to said plurality of
potential control actions, and a processor adapted to compare said
input to said sensor input value combinations and select said
control action from said plurality of control actions.
4. The apparatus of claim 3, wherein said plurality of potential
control actions includes a compressor shut down command, operation
parameter adjusting commands and commands for indicating that
maintenance is needed.
5. The apparatus of claim 4, wherein said control member is further
adapted to store information regarding at least one of sensor input
values, said control action and maintenance alarms in said
memory.
6. The apparatus of claim 3, further comprising a communication
member associated with said control member and adapted to allow
communication between said control member and a remote
location.
7. The apparatus of claim 6, wherein said plurality of control
actions includes a command to issue a signal through said
communication member.
8. The apparatus of claim 1, further comprising a display member
communicated with said control member, said control member being
adapted to display a message on said display member corresponding
to at least one of said input and said control action, and an
indication of at least one compressor shut down or maintenance
alarms; and to allow adjustment of at least one of said adjustable
operating parameters.
9. The apparatus of claim 1, wherein said control member is adapted
to identify a flooded start condition from said input.
10. The apparatus of claim 9, wherein said input includes suction
temperature, suction pressure, discharge pressure, discharge
temperature and oil pressure data, and said control actions include
issuing a flooded start warning, altering an operating parameter of
said compressor, shutting down said compressor, and combinations
thereof.
11. The apparatus of claim 1, wherein said control member is
adapted to identify a liquid slugging condition from said
input.
12. The apparatus of claim 11, wherein said input includes suction
temperature, suction pressure, discharge pressure, discharge
temperature and oil pressure data, and said control actions include
issuing a liquid slugging warning, altering an operating parameter
of said compressor, shutting down said compressor, and combinations
thereof.
13. The apparatus of claim 1, wherein said control member is
adapted to compare discharge temperature from said input to a
discharge temperature set point and to control a liquid injection
valve on said compressor based upon results of the comparison.
14. The apparatus of claim 13, wherein said control member is
adapted to open said liquid injection valve when said discharge
temperature is greater than said set point.
15. The apparatus of claim 13, wherein said control member has a
memory storing expected reactions to control actions taken on said
liquid injection valve, and wherein said control member is adapted
to compare actual change in said discharge temperatures to said
expected reactions so as to identify a malfunctioning liquid
injection valve.
16. The apparatus of claim 1, wherein said control member is
adapted to identify a liquid floodback condition from said
input.
17. A method for monitoring a compressor, comprising the steps of:
obtaining input regarding a plurality of compressor operating
parameters; feeding said input to a control member; analyzing said
input with said control member to determine a control action based
upon said input; and carrying out said control action on said
compressor.
18. The method of claim 17, wherein said input comprises compressor
discharge pressure, compressor discharge temperature, compressor
suction pressure, compressor suction temperature, oil pressure and
a compressor on/off input signal.
19. The method of claim 18, wherein said control member includes a
memory storing a plurality of potential control actions and a
plurality of sensor input value combinations corresponding to said
plurality of potential control actions; and wherein said control
member selects said control action from said plurality of potential
control actions.
20. The method of claim 19, wherein said plurality of potential
control actions include a compressor shut down command, operation
parameter adjusting commands and commands for indicating that
maintenance is needed.
21. The method of claim 19, further comprising the step of storing
information regarding at least one of said input and said control
action in said memory.
22. The method of claim 17, wherein said input is obtained from
sensors positioned within about 1 foot of said compressor.
23. The method of claim 17, further comprising the steps of
enabling communication of said control member with a remote
location, and at least one of (a) sending information related to
said control action to said remote location and (b) allowing access
to information regarding said control action from said remote
location.
24. In combination, a compressor and control module system,
comprising: a compressor; and a control module comprising a
plurality of sensor inputs for receiving input from said
compressor; at least one control action output for conveying
control actions to said compressor; and a control member
communicated with said plurality of sensor inputs and said control
action output, said control member being adapted to analyze input
from said plurality of sensor inputs, to determine a control action
based upon said input and to send said control action to said at
least one control action output.
25. The system of claim 24, wherein said control member has a
memory storing expected reactions to control actions taken on said
liquid injection valve, and wherein said control member is adapted
to compare actual change in said discharge temperatures to said
expected reactions so as to identify a malfunctioning liquid
injection valve.
26. The system of claim 24, further comprising a plurality of
sensors associated with said compressor and connected to said
sensor inputs.
27. The system of claim 24, wherein said plurality of sensors
comprises sensors for measuring compressor discharge pressure,
compressor discharge temperature, compressor suction pressure,
compressor suction temperature, oil pressure and compressor on/off
input signal.
28. The system of claim 24, wherein said control member includes a
memory storing a plurality of potential control actions and a
plurality of sensor input combinations corresponding to said
plurality of potential control actions.
29. The system of claim 28, wherein said plurality of potential
control actions include a compressor shut down command, operation
parameter adjusting commands and commands for indicating that
maintenance is needed.
30. The system of claim 28, wherein said control member is further
adapted to store information regarding at least one of said input
and said control action in said memory.
31. The system of claim 24 further comprising a communication
member associated with said control member and adapted to allow
communication between said control member and a remote
location.
32. The system of claim 31, wherein said at least one control
action includes a command to issue a signal through said
communication member.
33. The system of claim 24, further comprising a display member
communicated with said control member, said control member being
adapted to display a message on said display member corresponding
to said control action.
34. The system of claim 33, wherein said message includes a value
of at least one sensor input, status of at least one control output
and an indication of at least one compressor shut down or
maintenance alarm.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a compressor protection and control
module and a system and method incorporating same.
[0002] Compressor maintenance and reliability are critical issues.
In connection with reliability, a malfunctioning compressor can
cause difficulties spanning from minor inconvenience to loss of
valuable refrigerated product. Furthermore, compressors themselves
are costly equipment and improper maintenance or operation can
result in damage requiring expensive maintenance or
replacement.
[0003] Systems and methods are known for limited, local control and
protection of compressors. Such systems tend to focus on single
parameters to provide for emergency action. Although this is
helpful, such systems do not assist in identifying a potential
problem before the compressor is incapacitated.
[0004] In light of the foregoing, it is clear that the need remains
for improved compressor monitoring so as to avoid compressor shut
downs, if possible, and minimize expense due to compressor
repair/replacement, spoilage and the like.
[0005] Therefore, the primary objectives of the present invention
are to (1) provide a module for protecting a compressor which
detects trouble with the compressor before compressor failure, (2)
provide a module that can control key operating and control
functions based on monitored operating conditions and (3) provide
such a module, and a system and method incorporating same, wherein
preventive maintenance is facilitated.
[0006] Other objects and advantages of the present invention will
appear hereinbelow.
SUMMARY OF THE INVENTION
[0007] In accordance with the present invention, the foregoing
objects and advantages have been readily attained.
[0008] According to the invention, an apparatus for monitoring a
compressor is provided, which comprises a plurality of sensor
inputs for receiving input regarding operating parameters of a
compressor; at least one control action output for sending a
control action to said compressor; and a control member
communicated with said plurality of sensor inputs and said control
action output, said control member being adapted to analyze input
from said plurality of sensor inputs to determine a control action
based upon said input, and to send said control action to said at
least one control action output.
[0009] A display may be provided and adapted to show sensor input
values, control output and alarm status.
[0010] In further accordance with the present invention, a method
is provided for monitoring a compressor, which method comprises the
steps of obtaining input regarding a plurality of compressor
operating parameters; feeding said input to a control member;
analyzing said input with said control member to determine a
control action based upon said input; and carrying out said control
action on said compressor. A history of such control actions and
sensor inputs may be stored for later retrieval and analysis.
[0011] Still further according to the invention, a compressor and
control module system are provided, which comprises a control
module comprising a plurality of sensor inputs; at least one
control action output; and a control member communicated with said
plurality of sensor inputs and said control action output, said
control member being adapted to analyze input from said plurality
of sensor inputs, to determine a control action based upon said
input and to said control action to said at least one control
action output.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A detailed description of preferred embodiments of the
present invention follows, with reference to the attached drawing,
wherein FIG. 1 schematically illustrates a functional block diagram
of a compressor and module in accordance with the present
invention.
DETAILED DESCRIPTION
[0013] In accordance with the present invention, a compressor
protection module is provided which advantageously monitors a
combination of compressor operating parameters and which is
programmed to determine appropriate control actions based upon
combinations of sensor input. Verification of the control function
can also be accomplished by comparing the actual result to the
expected result. The module of the present invention can thereby
advantageously detect certain failure conditions before failure is
imminent, thereby reducing maintenance and repair costs and
avoiding potential damage to refrigerated product. The module can
also be programmed to maintain application specific operating
parameters as certain operating parameters and alarm setpoints can
be adjusted within a limited range.
[0014] Turning now to FIG. 1, a functional block diagram
schematically illustrates a compressor and module in accordance
with the present invention.
[0015] FIG. 1 shows a compressor chassis 10 and a module 12 in
accordance with the present invention. Module 12 includes a
processor 14 and a plurality of sensor inputs for measuring
compressor operating parameters. These inputs are preferably
connected to various probes and transducers including a discharge
thermistor probe 16 for measuring compressor discharge temperature,
a return gas thermistor probe 18 for measuring return gas
temperature or suction temperature, a suction pressure transducer
20 for measuring suction pressure, a discharge pressure transducer
22 for measuring discharge pressure and an oil discharge pressure
transducer 24 for measuring oil discharge pressure.
[0016] As shown in FIG. 1, the sensor inputs may also
advantageously include inputs 26 for power supply, compressor
on/off signal and safety input signal, a crank case heater current
transformer 28 which is preferably adapted to control and/or detect
operation of the crank case heater of the compressor, an output 30
for liquid injection valve control and outputs 32, 34 for providing
unloader control. Inputs for motor current and supply voltage could
also be provided.
[0017] Processor 14 in accordance with the invention is
advantageously communicated with each of these sensor inputs and
has memory programmed with a series of commands adapted to evaluate
different combinations of inputs from each sensor and thereby
identify correct operating conditions, operating conditions
indicating that the compressor is being improperly operated,
operating conditions indicating that the compressor needs
maintenance, operating conditions that indicate that the compressor
must be operated under different conditions to avoid damage, and
the like.
[0018] For example, control unit or processor 14 can advantageously
be programmed so as to detect conditions such as a flooded start,
liquid slugging, inadequate control of liquid injection volumes and
liquid floodback. Each of these conditions can be inferred from
different combinations of input from the sensor inputs, which will
then allow for appropriate control actions to be taken.
[0019] Module 12 of the present invention can also advantageously
be programmed to maintain a given operating condition and will
control the compressor in order to maintain the programmed
operating parameters. For example in refrigeration applications the
compressor is typically controlled to maintain the suction pressure
within a given range. By monitoring the suction pressure, module 12
can be programmed to start and stop the compressor and operate the
unloaders such that the desired suction pressure is maintained.
[0020] The various control actions that may be desirable, along
with appropriate input value combinations for using such control
actions, are stored in memory in module 12 for use in evaluating
actual input and selecting a suitable control action for the
compressor.
[0021] In further accordance with the present invention, module 12
advantageously is provided having an interface port 36 adapted for
connection with communication capability, for example through
CCN/LON or other communication network. This advantageously allows
for remote access from and to module 12 so that information can be
obtained from module 12 by personnel located at a remote location,
and information can be automatically sent by module 12 to a remote
location, as dictated by control actions corresponding to
combinations of input from the sensor inputs. The communications
can also be used to send commands to the module such as on/off
control, unloading control and the modification of adjustable
operating parameters. This communication can be by dedicated or
shared telephone access, for example using a modem, or wireless
access, or through any other manner known to persons of ordinary
skill in the art.
[0022] Module 12 in accordance with the present invention further
preferably includes a human interface 38 which may advantageously
be a display member for indicating various information to a user,
such as current operating status, detected fault conditions, and
the like. The display can also be utilized to modify adjustable
operating parameters such as unloading and liquid injection
setpoints and application specific warning parameters such as high
limits for return gas temperature and discharge temperature.
[0023] Still referring to FIG. 1, module 12 may advantageously be
communicated with a system control box 40 such that commands issued
by processor 14 can be enacted on the compressor, for example to
change operating speed, turn off power, control crankcase heater
operation, and the like,
[0024] Module 12 in accordance with the present invention
advantageously provides for two forms of compressor protection,
specifically, immediate and prognostic protection. Immediate
protection is provided for combinations of input indicating a
failure is occurring or likely to occur, and the compressor can be
immediately shut down or other action taken. Prognostic protection
is provided for combinations of sensor input that indicate
impending failure or degradation of compressor performance, and
suitable action may include adjusting the compressor operation
accordingly and issuance of a warning to the user and/or
maintenance personnel that compressor maintenance is required.
[0025] As set forth above, it is particularly advantageous in
accordance with the present invention to program module 12 and
processor 14 to detect certain types of conditions based upon input
from the different compressor sensors. It is preferred that the
input sensors include input as to compressor suction pressure,
compressor suction temperature, compressor discharge pressure,
compressor discharge temperature and oil pressure. It is important
to note that the entering (suction pressure and temperature) and
leaving (discharge pressure and temperature) refrigerant conditions
are measured for each individual compressor. With these factors,
flooded starts, liquid slugging and liquid floodback can be
detected, and appropriate action taken. With additional sensor
input as to the liquid injection set point, module 12 and processor
14 can be adapted to detect inadequate control of liquid injection
as well, and take appropriate action.
[0026] Thus, module 12 in accordance with the invention
advantageously allows protection of the compressor using local
sensors, preferably positioned within about one foot of the
compressor, which gather information for processing by module 12 to
take action dictated by programming in module 12 and also to allow
communication from remote locations, for example a monitoring
station at a completely different building, site or location, as
desired, so as to provide effective protection of the compressor
and, when applicable, products preserved by operation of the
compressor.
[0027] Flooded Start Detection
[0028] Liquid refrigerant will often return to a compressor during
an off cycle. Starting the compressor when it is filled with liquid
refrigerant can cause severe damage to the compressor including
compressor failure. In accordance with the present invention,
processor 14 is advantageously adapted to detect a flooded start,
as well as the severity of the flooded start, and to either warn
the user or shut down the compressor, as appropriate.
[0029] By examining the suction temperature, suction pressure,
discharge pressure, discharge temperature and oil pressure
variations during the startup of the compressor, processor 14 can
differentiate a flooded start as compared to a normal compressor
start, as well as the severity of same, and take an appropriate
control action.
[0030] Liquid Slugging
[0031] Liquid slugging is a major cause of compressor failure. A
refrigerant compressor is designed to compress vapor refrigerant
and pump the refrigerant through the refrigeration/air conditioning
system. Any liquid (i.e. non-compressible fluid), which is returned
to the compressor, even in small quantities, will stress the
compressor and can, in larger quantities, result in compressor
damage. By examining the suction temperature, suction pressure,
discharge pressure, discharge temperature and oil pressure
variations during a period of liquid slugging, processor 14 can
detect such slugging and, depending upon the severity of same, take
a control action including sending a warning to a user or
maintenance personnel, or shut down the compressor, or both.
[0032] Liquid Injection Control
[0033] Inadequate control of liquid injection can result in
inefficient compressor operation and possible compressor failure.
Certain high compression ratio operating conditions require liquid
refrigerant to be injected in the compressor suction stream in
order to maintain the compressor discharge temperature within
acceptable operating limits. In accordance with the present
invention, the amount of liquid injection is optimized based on
energy efficiency and temperature reliability requirements, and
operation of the liquid injection valve is confirmed by comparing
reduction in discharge temperature to an expected reduction in
discharge temperature. Providing good liquid control optimizes
compressor energy efficiency and reliability.
[0034] In accordance with the present invention, the opening of the
liquid injection valve (output on module 12 ) is controlled based
on the liquid injection set point and the measured compressor
discharge temperature. If the discharge temperature rises above the
set point, the valve opens until the discharge temperature drops
below the set point. By evaluating the response of the valve (i.e.,
the measured reduction in discharge temperature) the module can
determine if the valve is working properly by comparing the actual
reduction in discharge temperature to the expected reduction in
discharge temperature.
[0035] Liquid Floodback
[0036] Liquid floodback is a major cause of compressor failure.
Liquid refrigerant returned to the compressor is one of the leading
causes of compressor failure, and module 12 in accordance with the
present invention is advantageously adapted to determine if, and to
what extent, liquid refrigerant is entering the compressor.
[0037] Processor 14 advantageously is adapted to calculate or
determine suction superheat to determine if liquid refrigerant is
entering the compressor. If excessive liquid refrigerant is
returned to the compressor, it will extract heat from the
refrigerant stream when it boils off thus resulting in lower
operating temperatures. An expected compressor discharge
temperature is calculated and compared to the measured actual
discharge temperature to determine the extent of the floodback.
[0038] The module is programmed with refrigerant properties such
that it can calculate characteristics of the refrigerant type in
use. With this information, processor 14 calculates a saturation
temperature based upon refrigerant property tables and suction
pressure. The suction superheat is then determined by subtracting
the saturation temperature from the suction temperature. If the
suction superheat is below a warning threshold, the user is warned
of a floodback condition.
[0039] The expected discharge temperature is calculated as a
function of pressure ratio, suction temperature, compression
coefficient and compressor type. This is based upon the discovery
that evaporation of liquid refrigerant returned to the compressor
will suppress the discharge temperature. The difference between the
expected discharge temperature and actual discharge temperature is
proportional to the amount of liquid refrigerant returned to the
compressor.
[0040] Although the foregoing lists four particularly preferably
conditions which module 12 in accordance with the present invention
is adapted to detect, a further listing of conditions corresponding
to different sensor input and appropriate control actions
corresponding to same is provided in Table 1 below.
1TABLE 1 Failure Mode Possible Control Sensor(s) or Symptom
Description Action(s) Required High High discharge pressure at Turn
off the compressor Discharge Pressure Pressure the discharge side
of the if the discharge Protection compressor. pressure exceeds a
threshold value. Compressor Compressor Overheating is a Turn off
the compressor Discharge Temperature Overheating major cause of
compressor if the discharge failures. It has the temperature
exceeds a following potential causes: threshold value. - broken
discharge valve Unload Compressor. - low refrigerant charge -
liquid injection failure - cylinder head cooling fan failure Low
Oil Low oil pressure is also a Turn the compressor off Oil Pressure
Pressure major cause of compressor if inadequate net oil Suction
Pressure failures as it results in a pressure is developed. * net
oil pressure lack of lubrication. It calculated as oil has the
following potential pressure - suction causes: pressure - liquid
refrigerant in crankcase - high compressor wear - bad oil pump.
High Return High suction gas Warn user of high Suction gas Gas
temperatures returned to suction temperatures. temperature
Temperature the compressor can result in inadequate motor cooling
and compressor overheating. High High compressor cycling is Limit
compressor Run/Stop Signal Compressor generally an indication of
cycling by including a Cycles a bad system design or minimum off
time. refrigerant control Warn user of high problems. High
compressor compressor cycles. cycles can lead to premature
compressor failures. Low Low refrigerant charge can Turn compressor
off Suction Pressure Refrigerant result in high motor and during
low suction Discharge Temperature Charge discharge temperatures and
pressures or high freeze up of the discharge temperatures.
evaporator. Motor The motor can overheat due Turn the compressor
off Discharge Temperature Overheating to inadequate refrigerant at
high discharge cooling or running the temperatures. compressor
above its design limits. Liquid Liquid refrigerant returned Warn
user when Suction Temperature Refrigerant to the compressor in the
suction/discharge Suction Pressure Floodback suction gas stream.
superheat is low. Discharge Pressure Generally caused by Shut down
compressor Discharge Temperature excessive refrigerant feed with
excessive through the expansion floodback valve. Liquid Relatively
large amounts of Turn on warning light Suction Temperature Slugging
liquid (refrigerant and/or or alarm. Suction Pressure oil) returned
to the Record fault in memory. Discharge Pressure compressor in a
short Shut down compressor if Discharge Temperature period of time.
excessive Flooded When a large volume of Turn on crankcase Suction
Temperature Start refrigerant accumulates in heater. Suction
Pressure the crankcase or oil sump Warn user of alarm. Discharge
Pressure at shut down it dilutes Turn compressor off if Discharge
Temperature oil. This can in turn lead excessive to a lack of
compressor lubrication.
[0041] As can be seen, a substantial list of potential failure
modes or symptoms,and corresponding control actions are available
and can be incorporated into the programming of module 12 in
accordance with the present invention. In some instances, failures
can be determined using different sensors. For example, as shown in
Table 1, refrigerant floodback can be determined from input
obtained from four different sensor combinations.
[0042] It is anticipated that the module in accordance with the
present invention can advantageously be used to reduce failure rate
of a large number of compressor parts, including for example main
bearings, crankshaft, head gasket, discharge valve, suction valve,
motor and connecting rods, and the like.
[0043] In order to perform the desired operations in accordance
with the present invention, module 12 and processor 14 are
advantageously provided with control functions utilizing triac
outputs, specifically, triac outputs for CR1, CR2, liquid
injection, crankcase heater on/off, alarm, unloader 1 and unloader
2.
[0044] Module 12 may advantageously be provided having non-volatile
memory which can be accessed from remote locations as identified
above, and is advantageously adapted to save operational data so as
to assist in diagnosing problems. For example, it is anticipated
that 8 K of non-volatile memory would be suitable for such purpose,
although different amounts of memory may be desired.
[0045] Fault conditions are also preferably saved in such memory
for later retrieval.
[0046] Human interface 38 in accordance with the present invention
may advantageously consist of any known devices for communicating
information to the user, such as LED digits, LED's and buttons.
Such an interface allows a user to monitor compressor operational
status, to monitor compressor output status, to monitor compressor
input values, and to setup configuration values. Human interface 38
may advantageously be directly driven by module 12, and processor
14 of same, and may have any combination of display elements
suitable for conveying the desired information, for example, three
8-segment LED's, three push buttons, and eighteen individual LED's
could be provided for conveying such information.
[0047] Human interface 38 may further include a display listing
various faults, for example, over current, high pressure, low
pressure, oil pressure, floodback, motor temperature and crankcase
heater malfunction. Such listings can be adapted to display one or
more items as desired, for example, with LED's next to each item on
the list, or in other manners well known to a person of ordinary
skill in the art, and are communicated with processor 14 such that
control actions selected by processor 14 can include commands for
operating interface 38 so as to provide appropriate displays as
well.
[0048] In accordance with the foregoing, it should readily be
appreciated that a module has been provided which can be used with
compressors of varying types, for example screw compressors,
reciprocating compressors, scroll compressors, rotary compressors
and others, so as to detect impending failure and take appropriate
action. The module is particularly advantageous as compared to
conventional systems in that actions are taken based upon
combinations of input from different portions of the compressor,
and remote actions are enabled. This advantageously allows for both
prognostic and immediate protection of the compressor.
[0049] It is to be understood that the invention is not limited to
the illustrations described and shown herein, which are deemed to
be merely illustrative of the best modes of carrying out the
invention, and which are susceptible of modification of form, size,
arrangement of parts and details of operation. The invention rather
is intended to encompass all such modifications which are within
its spirit and scope as defined by the claims.
* * * * *