U.S. patent application number 13/835807 was filed with the patent office on 2013-10-17 for compressed gas supply unit, compressed gas supply apparatus and control method of said unit and said apparatus.
The applicant listed for this patent is ANEST IWATA CORPORATION. Invention is credited to Tamotsu FUJIOKA, Kenji MATSUZAKI, Atsushi UNAMI.
Application Number | 20130272840 13/835807 |
Document ID | / |
Family ID | 49325252 |
Filed Date | 2013-10-17 |
United States Patent
Application |
20130272840 |
Kind Code |
A1 |
FUJIOKA; Tamotsu ; et
al. |
October 17, 2013 |
COMPRESSED GAS SUPPLY UNIT, COMPRESSED GAS SUPPLY APPARATUS AND
CONTROL METHOD OF SAID UNIT AND SAID APPARATUS
Abstract
A compressed gas supply unit includes compressors. Gas
discharged from the compressors is stored in a storage tank and
then supplied to a gas recipient. The pressure of the storage tank,
the operation temperature and the power consumption of each
compressor, and the temperature around the compressors are sent to
a controller and a monitoring device. A determination unit of the
controller determines the presence or absence of the abnormality of
the compressor from a difference between the operation temperature
of the compressor and the temperature around the compressors. An
effective load calculation unit calculates the effective load of
each compressor from the power consumption of the compressor and
the pressure of the storage tank. The controller controls the
compressors based on the calculated effective load such that the
loads of the compressors are equalized. An estimation unit
estimates maintenance timing from the effective load.
Inventors: |
FUJIOKA; Tamotsu;
(Yokohama-shi, JP) ; UNAMI; Atsushi;
(Yokohama-shi, JP) ; MATSUZAKI; Kenji;
(Yokohama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ANEST IWATA CORPORATION |
Yokohama-shi |
|
JP |
|
|
Family ID: |
49325252 |
Appl. No.: |
13/835807 |
Filed: |
March 15, 2013 |
Current U.S.
Class: |
415/1 ;
415/118 |
Current CPC
Class: |
F04D 27/0269 20130101;
F04D 27/001 20130101; F04D 27/00 20130101 |
Class at
Publication: |
415/1 ;
415/118 |
International
Class: |
F04D 27/00 20060101
F04D027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2012 |
JP |
2012-079612 |
Claims
1. A compressed gas supply unit comprising a plurality of
compressors, a storage tank which stores discharge gas of the
compressors, a compressed gas supply pipe which supplies compressed
gas to a gas recipient from the storage tank, and a pressure sensor
which detects a pressure of the storage tank, the compressed gas
supply unit controlling an operation of each of the compressors
based on a detected value of the pressure sensor, and comprising:
an operating state amount sensor which detects an operating state
amount of the compressor; a power sensor which detects a power
consumption of each compressor; and a controller which controls the
operation of each compressor, wherein the controller comprises a
determination unit which determines that the compressor is abnormal
when the detected value of the operating state amount sensor
exceeds a threshold, an effective load calculation unit which
calculates an effective load of each compressor from the detected
values of the power sensor and the pressure sensor, and an
estimation unit which estimates a maintenance timing of each
compressor from an average value of the calculated effective load
in an operation time, and the controller controls the operation of
each compressor based on the calculated effective load of each
compressor such that loads of the compressors are equalized.
2. The compressed gas supply unit according to claim 1, wherein the
effective load calculation unit for the compressors is a unit which
determines a correlation map of the power sensor, the pressure
sensor, and the effective load from a pre-measured value and
determines the effective load of the compressor from the
correlation map.
3. The compressed gas supply unit according to claim 1, wherein the
operating state amount sensor comprises a first temperature sensor
which detects an air temperature around the compressors, and a
second temperature sensor which detects an operation temperature of
each compressor, and the determination unit of the controller is a
unit which determines that the compressor is abnormal when a
difference between the detected values of the first temperature
sensor and the second temperature sensor exceeds a threshold.
4. The compressed gas supply unit according to claim 1, wherein the
operation state amount sensor is a second pressure sensor which
detects a pressure of the discharge gas of the compressor, and the
determination unit of the controller is a unit which determines
that the compressor is abnormal when a difference between the
detected values of the pressure sensor and the second pressure
sensor exceeds a threshold.
5. The compressed gas supply unit according to claim 1, wherein
each compressor comprises an inverter capable of controlling an
RPM, and the controller controls the inverter such that loads of
the compressors are equalized.
6. A compressed gas supply apparatus comprising: a plurality of the
compressed gas supply units according to claim 1 disposed at
positions apart from each other; and a central controller which can
perform data communication by means of a wireless access system
with the plurality of compressed gas supply units, wherein the
central controller comprises a storage unit which stores detected
value data received from the plurality of compressed gas supply
units, and a correction unit which corrects the threshold from the
detected value data accumulated in the storage unit and a result of
an actual abnormality occurrence of the compressor, and controls
each of the compressed gas supply units based on the corrected
threshold.
7. A compressed gas supply apparatus comprising: a plurality of the
compressed gas supply units according to claim 1 disposed at
positions apart from each other; a central controller which can
perform data communication by means of a wireless access system
with the plurality of compressed gas supply units; a connection
pipe which connects the compressed gas supply pipes of the
plurality of compressed gas supply units; and an on-off valve
provided in the connection pipe, wherein the central controller
remotely controls the on-off valve based on a detected value of a
pressure of a storage tank received from each of the plurality of
compressed gas-supply units.
8. A control method of a compressed gas supply unit which
temporarily stores discharged gas of a plurality of compressors in
a storage tank, supplies compressed gas to a gas recipient from the
storage tank, detects a pressure of the storage tank, and controls
an operation of each of the compressors based on a detected value
of the pressure, the control method comprising: a first step of
detecting an operating state amount of each compressor and
determining that the compressor is abnormal when the detected value
exceeds a threshold; a second step of detecting a power consumption
of each compressor and an internal pressure of the storage tank,
calculating an effective load of each compressor from the detected
values, and estimating a maintenance timing of each compressor from
an average value of the calculated effective load in an operation
time; and a third step of controlling the operation of each
compressor based on the effective load of each compressor
calculated in the second step such that the effective loads of the
compressors are equalized.
9. The control method of a compressed gas supply unit according to
claim 8, wherein the first step is a step of detecting an air
temperature around the compressors and an operation temperature of
each compressor and determining that the compressor is abnormal
when a difference between these detected temperature values exceeds
a threshold.
10. The control method of a compressed gas supply unit according to
claim 8, wherein the first step is a step of detecting the internal
pressure of the storage tank and a pressure of the discharge gas of
each compressor and determining that the compressor is abnormal
when a difference between these detected pressure values exceeds a
threshold.
11. The control method of a compressed gas supply unit according to
claim 9, wherein each compressor is constituted of a multi-stage
compressor, and the operation temperature or the pressure of the
discharge gas of the compressor is the operation temperature or the
pressure of the discharge gas of the compressor other than a final
high-pressure stage compressor.
12. A control method of a compressed gas supply apparatus
comprising: a plurality of compressed gas supply units which are
disposed at positions apart from each other, temporarily store
discharge gas of a plurality of compressors in a storage tank,
supply compressed gas to a gas recipient from the storage tank,
detect a pressure of the storage tank, and control an operation of
each of the compressors based on a detected value of the pressure;
and a central controller which can perform data communication by
means of a wireless access system with the compressed gas supply
units, the control method comprising: a first step of detecting an
operating state amount of each compressor and determining that the
compressor is abnormal when the detected value thereof exceeds a
threshold; a second step of detecting a power consumption of each
compressor and an internal pressure of the storage tank,
calculating an effective load of each compressor from the detected
values, and estimating a maintenance timing of each compressor from
an average value of the calculated effective load in an operation
time; a third step of controlling the operation of each compressor
based on the effective load of each compressor calculated in the
second step such that the effective loads of the compressors are
equalized; a fourth step of transmitting detected value data to the
central controller from the compressed gas supply units; a fifth
step of causing a storage unit of the central controller to store
the detected value data of the compressed gas supply units; and a
sixth step of correcting the threshold from the detected value data
accumulated in the storage unit and a result of an actual
abnormality occurrence of the compressor and controlling each
compressed gas supply unit based on the corrected threshold.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a compressed gas supply
unit which includes a plurality of compressors and allows the
energy-saving operation of the compressors and saving of a
maintenance cost, a compressed gas supply apparatus, and a control
method of the unit and the apparatus.
[0003] 2. Description of the Related Art
[0004] There is known a compressed gas supply unit which includes a
plurality of compressors and supplies compressed gas to a gas
recipient while controlling the number of compressors under
operating condition according to a demand. In such a compressed gas
supply unit, energy saving is achieved by minimizing the number of
compressors under operating condition. Japanese Patent Application
Laid-open No. 2010-190197 discloses a compressed gas supply unit
which includes a shared storage tank which stores gas discharged
from a plurality of compressor and a pressure sensor which detects
the internal pressure of the storage tank, grasps a change in the
amount of consumed gas using the internal pressure of the storage
tank, and controls the number of compressors under operating
condition according to the detected value of the pressure
sensor.
[0005] Japanese Patent Application Laid-open No. 2010-53733
discloses that, in a compressed gas supply unit having a plurality
of air compressors, the surplus of the ability of each air
compressor is calculated from a power consumption amount measured
in each air compressor under operating condition in the control of
the number of operated compressors. In addition, Japanese Patent
Application Laid-open No. 2003-91313 discloses a remote monitoring
system which remotely monitors the operation of a plurality of
compressors disposed at remote sites. In the remote monitoring
system, a server of a server-client system is provided in a remote
monitoring center, and operation information on the compressors
separately disposed in a plurality of client plants and the like is
downloaded into the server via the Internet or a public
network.
[0006] Japanese Patent Application Laid-open No. 2008-258935
discloses a remote monitoring system in which a plurality of
compressors are connected to a personal computer with a LAN (wired)
cable and the operating states of the plurality of compressors are
monitored using the personal computer.
[0007] Although Japanese Patent Application Laid-open No.
2010-53733 discloses that the surplus of the ability of each
compressor is calculated from the power consumption of each
compressor, the pressure on the discharge side of the compressor
also influences the power consumption of the compressor, and hence
it is not possible to accurately calculate the surplus of the
compressor only from the power consumption of the compressor. That
is, with the recent prevalence of an inverter, the load fluctuation
of the compressor is no longer raster. In addition, the power
efficiency of the compressor changes depending on the way to
operate the compressor. For example, the power efficiency of the
compressor in an unloaded operation is lowered.
[0008] In the system in which the compressor provided in the client
plant and the personal computer provided in the monitoring center
or the like are connected with the LAN cable as the remote
monitoring system of a compressed gas supply apparatus, information
on other clients may be leaked out of the LAN cable, and hence the
system has a security problem. In addition, the system requires a
construction cost for providing a network line to the
compressor.
[0009] In the compressed gas supply unit, energy saving can be
achieved by the combined use of an operation in which a plurality
of compressors are operated with equal loads and control of the
number of compressors under operating condition. In addition, with
the equal load operation, it is possible to eliminate an
irregularity in the maintenance timing of the compressor and reduce
the maintenance frequency of the entire compressed gas supply unit
to thereby save a maintenance cost and improve the utilization rate
of the compressed gas supply unit.
SUMMARY OF THE INVENTION
[0010] In view of the problem of the conventional art described
above, a first object of the present invention is to provide a
compressed gas supply unit including a plurality of compressors
which allows an equal load operation of the plurality of
compressors while monitoring the operating state of each compressor
and achieves energy saving and saving of a maintenance cost by
using the equal load operation and control of the number of
compressors under operating condition in combination. A second
object of the present invention is to realize a low-cost remote
control unit without any security problem in a case where a
plurality of the compressed gas supply units disposed at positions
apart from each other are remotely controlled.
[0011] A compressed gas supply unit of a first aspect of the
present invention (hereinafter referred to as "an apparatus of a
first aspect of the present invention") is a compressed gas supply
unit including a plurality of compressors, a storage tank which
stores discharged gas of the compressors, a compressed gas supply
pipe which supplies compressed gas to a gas recipient from the
storage tank, and a pressure sensor which detects a pressure of the
storage tank, the compressed gas supply unit controlling an
operation of each of the compressors based on a detected value of
the pressure sensor, and including an operating state amount sensor
which detects an operating state amount of the compressor, a power
sensor which detects a power consumption of each compressor, and a
controller which controls the operation of each compressor.
[0012] The controller includes a determination unit which
determines that the compressor is abnormal when the detected value
of the operation state amount sensor exceeds a threshold, an
effective load calculation unit which calculates an effective load
of each compressor from the detected values of the power sensor and
the pressure sensor, and an estimation unit which estimates a
maintenance timing of each compressor from an average value of the
calculated effective load in an operation time. The operation time
may be, e.g., the operation time of the compressed gas supply unit
after the previous maintenance, but is not particularly limited
thereto.
[0013] The determination unit determines the presence or absence of
the abnormality of each compressor, and the operation of each
compressor is controlled based on the effective load of each
compressor calculated by the effective load calculation unit such
that the loads of the compressors are equalized. In addition, the
maintenance is executed based on the maintenance timing estimated
by the estimation unit.
[0014] The effective load calculation unit detects the power
consumption of each compressor and the internal pressure of the
storage tank, and calculates the effective load of each compressor
from the detected values. The effective load of the compressor is
influenced not only by the power consumption of the compressor, but
also by the internal pressure of the storage tank. Consequently,
both of the power consumption of the compressor and the internal
pressure of the storage tank are detected and the effective load of
each compressor is calculated from the two detected values, and
hence it is possible to accurately calculate the effective load.
Next, the average value of the calculated effective load in the
operation time is calculated and the maintenance timing is
estimated from the foregoing average value, and hence it is
possible to estimate the accurate maintenance timing.
[0015] Thus, since the equal load operation of the compressors is
performed based on the calculated effective load, the energy saving
of the compressed gas supply unit is made possible by the combined
use of the equal load operation and control of the number of
compressors under operating condition. In addition, with the equal
load operation, it is possible to eliminate an irregularity in the
maintenance timing of the compressor and reduce the maintenance
frequency of the entire compressed gas supply unit. As a result, it
is possible to save the maintenance cost and also improve the
utilization rate of the compressed gas supply unit. Further, with
the estimation unit, it is possible to accurately estimate the
maintenance timing of the compressor.
[0016] The effective load calculation unit may be a unit which
determines a correlation map of the power sensor, the pressure
sensor, and the effective load from a pre-measured value and
determines the effective load of the compressor from the
correlation map. With this, even in a case where at least a part of
the compressors is in an unloaded operation, which is inefficient
in power, or an inverter is incorporated into the compressor, it is
possible to accurately grasp the effective load of the compressor,
whereby it becomes possible to perform control of the optimum and
minimum number of compressors and achieve the energy saving.
[0017] The operation state amount sensor may include a first
temperature sensor which detects an air temperature around the
compressors, and a second temperature sensor which detects an
operation temperature of each compressor, and the determination
unit of the controller may be a unit which determines that the
compressor is abnormal when a difference between the detected
values of the first temperature sensor and the second temperature
sensor exceeds a threshold. The operation temperature of the
compressor is, e.g., the temperature of the discharged gas or a
discharge path, or the temperature of a partition forming a
compression chamber. With this, it is possible to eliminate the
influence of the air temperature around the compressors exerted on
the operation temperature of the compressor and accurately grasp
the presence or absence of the abnormality of the compressor. In
addition, since the temperature sensor is used, it is possible to
make the apparatus configuration relatively simple and make its
cost lower.
[0018] The operation state amount sensor may be a second pressure
sensor which detects a pressure of the discharged gas of the
compressor, and the determination unit of the controller may be a
unit which determines that the compressor is abnormal when a
difference between the detected values of the pressure sensor and
the second pressure sensor exceeds a threshold. With this, it
becomes possible to perform the accurate determination without the
influence of the internal pressure of the storage tank.
[0019] The apparatus of the first aspect of the present invention
may include an inverter capable of controlling the RPM of the
compressor, and the controller may control the operation of the
compressor via the inverter. With this, it is possible to
individually control the loads of the compressors, and hence the
equal load operation is facilitated.
[0020] A compressed gas supply apparatus of a second aspect of the
present invention (hereinafter referred to as "an apparatus of a
second aspect of the present invention") includes a plurality of
the compressed gas supply units disposed at positions apart from
each other and a central controller which can perform data
communication by means of a wireless access system with the
plurality of compressed gas supply units. The central controller
includes a storage unit which stores detected value data received
from the plurality of compressed gas supply units, and a correction
unit which corrects the threshold from the detected value data
accumulated in the storage unit and a result of an actual
abnormality occurrence of the compressor, and controls each of the
compressed gas supply units based on the corrected threshold.
[0021] The result of the actual abnormality occurrence of the
compressor mentioned herein means, e.g., data obtained when an
operator visually identifies the abnormality, and the operator
inputs the data such as the threshold or the like at the time of
the identification in the central controller. According to the
apparatus of the second aspect of the present invention, by
successively correcting the threshold in conjunction with watching
the result of the actual abnormality occurrence of the compressor,
it is possible to accurately determine the presence or absence of
the abnormality of the compressor. In addition, the presence or
absence of the abnormality of the compressor is determined based on
a population of the high detected values collected from the
plurality of compressed gas supply units, and hence it becomes
possible to perform the accurate determination.
[0022] A compressed gas supply apparatus of the present invention
(hereinafter referred to as "an apparatus of a third aspect of the
present invention") includes a plurality of the compressed
gas-supply units disposed at positions apart from each other, a
central controller which remotely controls the operation of the
plurality of compressed gas supply units, a connection pipe which
connects the compressed gas supply pipes of the plurality of
compressed gas supply units, and an on-off valve provided in the
connection pipe, and the central controller remotely controls the
on-off valve based on a detected value of a pressure of a storage
tank received from each of the plurality of compressed gas supply
units.
[0023] According to the apparatus of the third aspect of the
present invention, it is possible to supply the compressed gas to a
plurality of gas recipients via the connection pipe from one
compressed gas supply unit. In addition, it is possible to send the
compressed gas to the plurality of gas recipients in conjunction
with monitoring the storage state of the compressed gas in the
storage tank of each compressed gas supply unit by means of the
central controller, whereby it is possible to efficiently utilize
the compressed gas produced by the plurality of compressed gas
supply units.
[0024] A control method of a compressed gas supply unit of the
present invention (hereinafter referred to as "a method of a first
aspect of the present invention") is for a compressed gas supply
unit which temporarily stores discharged gas out of a plurality of
compressors in a storage tank, supplies compressed gas to a gas
recipient from the storage tank, detects an internal pressure of
the storage tank, and controls an operation of each of the
compressors based on a detected value of the pressure.
[0025] A first step of the method of the first aspect of the
present invention detects an operating state amount of each of the
plurality of compressors and determines that the compressor is
abnormal when the detected value exceeds a threshold. As the
operation state amount, for example, the air temperature around the
compressors and the operation temperature of each compressor are
detected and it is determined that the compressor is abnormal when
a difference between these detected temperature values exceeds a
threshold. With this, it is possible to eliminate the influence of
the air temperature around the compressors exerted on the
compressor and accurately grasp the presence or absence of the
abnormality of the compressor. In addition, since the temperature
sensor is used, it is possible to make the apparatus configuration
relatively simple and make its cost lower. As described above, the
operation temperature of the compressor is, e.g., the temperature
of the discharged gas or the discharge path, or the temperature of
the partition forming the compression chamber.
[0026] As another step, the internal pressure of the storage tank
and a pressure of the discharged gas of each compressor may be
detected and it may be determined that the compressor is abnormal
when a difference between these detected pressure values exceeds a
threshold. With this, it becomes possible to perform the accurate
determination without the influence of the internal pressure of the
storage tank. In addition, since the internal pressure of the
storage tank and the pressure of the discharge gas of each
compressor are detected, it becomes possible to perform the
accurate determination.
[0027] A second step detects a power consumption of each compressor
and the internal pressure of the storage tank, and calculates an
effective load of each compressor from these detected values. The
effective load of the compressor is influenced not only by the
power consumption of the compressor, but also by the internal
pressure of the storage tank. Consequently, both of the power
consumption of the compressor and the internal pressure of the
storage tank are detected and the effective load of each compressor
is calculated from the two detected values so that it is possible
to accurately calculate the effective load. Next, an average value
of the calculated effective load in an operation time is calculated
and maintenance timing is estimated from the average value. With
this, it becomes possible to estimate the accurate maintenance
timing. The operation time may be, e.g., the operation time of the
compressed gas supply unit after the previous maintenance, but is
not particularly limited thereto.
[0028] A third step controls the operation of each compressor based
on the effective load of each compressor calculated in the second
step such that the loads of the compressors are equalized. The
energy saving of the compressed gas supply unit is made possible by
the combined use of the equal load operation and the control of the
number of compressors under operating condition. In addition, with
the equal load operation, it is possible to eliminate the
irregularity in the maintenance timing of the compressor and reduce
the maintenance frequency of the entire compressed gas supply unit,
whereby it is possible to save the maintenance cost and improve the
utilization rate of the compressed gas supply unit.
[0029] Note that, when the compressor is constituted of a
multi-stage compressor, the first step may detect the operation
temperature or the pressure of the discharged gas of the
compressors other than the final high-pressure stage compressor.
When an abrasion is caused in the discharge path of a low-pressure
side compressor by the operation of the multi-stage compressor,
high-temperature and high-pressure gas of a high-pressure side
compressor flows backward to the low-pressure side compressor and
the temperature of the discharge path and the pressure of the
discharge gas of the low-pressure side compressor are increased.
Consequently, by detecting the temperature of the discharge path or
the pressure of the discharge gas of the low-pressure side
compressor, it is possible to detect the presence or absence of the
backward flow of the high-temperature and high-pressure gas. With
this, it is possible to accurately grasp the progress of fatigue of
the compressor, and hence it is possible to properly estimate the
maintenance timing.
[0030] A control method of a compressed gas supply apparatus of the
present invention (hereinafter referred to as "a method of a second
aspect of the present invention") is for a compressed gas supply
apparatus which includes a plurality of the compressed gas supply
units disposed at positions apart from each other and a central
controller which can perform data communication by means of a
wireless access system with the compressed gas supply units.
[0031] First to third steps of the method of the second aspect of
the present invention are the same as the first to third steps of
the method of the first aspect of the present invention. Fourth to
sixth steps of the method of the second aspect of the present
invention include the fourth step of transmitting detected value
data to the central controller from the compressed gas supply
units, the fifth step of causing a storage unit of the central
controller to store the detected value data of the compressed gas
supply units, and the sixth step of correcting the threshold from
the detected value data accumulated in the storage unit and a
result of an actual abnormality occurrence of the compressor and
controlling each compressed gas supply unit based on the corrected
threshold.
[0032] The result of the actual abnormality occurrence of the
compressor mentioned herein means, e.g., data obtained when the
operator visually identifies the abnormality, and the operator
inputs the data such as the threshold or the like at the time of
the identification in the central controller. By successively
correcting the threshold from the result of the actual abnormality
occurrence of the compressor, it is possible to determine the
presence or absence of the abnormality of the compressor further
accurately. In addition, the presence or absence of the abnormality
of the compressor is determined based on the population of the high
detected values collected from the plurality of compressed gas
supply units, and hence it becomes possible to perform the accurate
determination.
[0033] According to the apparatus of the first aspect of the
present invention and the method of the first aspect of the present
invention, since it is possible to accurately grasp the abnormality
of the compressor during the operation and perform the operation in
which the loads of the compressors are equalized, the combined use
of the equal load operation and the control of the number of
operated compressors allows energy saving, and can reduce the
maintenance frequency and save the maintenance cost. In addition,
according to the apparatus of the second aspect of the present
invention and the method of the second aspect of the present
invention, in addition to the operation and effect described above,
by successively correcting the threshold related to the difference
between the air temperature around the compressors and the
operation temperature of the compressor, it is possible to
determine the presence or absence of the abnormality of the
compressor further accurately. Additionally, according to the
apparatus of the third aspect of the present invention, it is
possible to efficiently supply the compressed gas produced by the
plurality of compressed gas supply units to a plurality of gas
recipients on the demands thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a system diagram of a compressed gas-supply unit
according to a first embodiment of each of an apparatus of a first
aspect of the present invention and a method of a first aspect of
the present invention;
[0035] FIG. 2 is a correlation map for determining the effective
load of a compressor in the first embodiment;
[0036] FIG. 3 is a partial system diagram of a compressed gas
supply unit according to a second embodiment of each of the
apparatus of the first aspect of the present invention and the
method of the first aspect of the present invention;
[0037] FIG. 4 is a system diagram of a compressed gas supply
apparatus according to an embodiment of each of an apparatus of a
second aspect of the present invention and a method of a second
aspect of the present invention; and
[0038] FIG. 5 is a system diagram of a compressed gas supply
apparatus according to an embodiment of an apparatus of a third
aspect of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Hereinbelow, the present invention will be described in
detail by using embodiments shown in the drawings. Note that the
scope of the present invention is not limited to dimensions,
materials, shapes, and relative arrangements of constituent parts
described in the embodiments unless specifically described.
First Embodiment
[0040] A first embodiment of each of an apparatus of a first aspect
of the present invention and a method of a first aspect of the
present invention will be described with reference to FIGS. 1 and
2. A compressed gas supply unit 10A of the present embodiment
includes one storage tank 12 and four compressors 14a to 14d.
Discharge paths 16a to 16d of the individual compressors are
connected to a main supply pipe 18, and the main supply pipe 18 is
connected to the storage tank 12. Gas discharged from each
compressor flows through the main supply pipe 18 and is stored in
the storage tank 12.
[0041] The individual compressors are provided with drive motors
20a to 20d and inverters 22a to 22d which can control the RPMs of
the drive motors steplessly. With this, the RPMs of the individual
motors can be individually controlled. Temperature sensors 24a to
24d which detect the temperatures of compressed gas are provided on
the partitions of compression chambers of the individual
compressors. The compressors are provided with power sensors 26a to
26d which detect power consumptions of the drive motors 20a to
20d.
[0042] The storage tank 12 is provided with a pressure sensor 28
which detects an internal pressure in the storage tank 12. A
temperature sensor 32 which detects an air temperature around the
compressors is provided in the vicinity of the compressors 14a to
14d. Detection signals of the temperature sensors 24a to 24d, the
power sensors 26a to 26d, the pressure sensor 28, and the
temperature sensor 32 are sent to a controller 34 provided in a
monitoring room or the like.
[0043] The controller 34 opens or closes an on-off valve 39
provided in a compressed gas supply pipe 38 to supply compressed
gas to a gas recipient 30 in conjunction with monitoring the
detected value of the pressure sensor 28. The controller 34 has a
determination unit 35, an effective load calculation unit 36, and
an estimation unit 37. The determination unit 35 determines the
presence or absence of the abnormality of each of the compressors
14a to 14d from a difference .DELTA.T between the detected value of
the temperature sensor 32 and the detected value of each of the
temperature sensors 24a to 24d. That is, when the difference
.DELTA.T exceeds a threshold .DELTA.Ts, the determination unit 35
determines that the state of the compressor is abnormal.
[0044] The effective load calculation unit 36 calculates the
effective load of each of the compressors 14a to 14d from the
detected values of the pressure sensor 28 and the power sensors 26a
to 26d. FIG. 2 is a map showing the correlation of the power
consumption of each of the compressors 14a to 14d, the internal
pressure of the storage tank 12, and the effective load of each of
the compressors 14a to 14d which are determined from pre-measured
test data by using the compressor having the same type and capacity
as those of each of the compressors 14a to 14d. The effective load
of each of the compressors 14a to 14d is calculated from the
detected values of the pressure sensor 28 and the power sensors 26a
to 26d by using the map.
[0045] The estimation unit 37 estimates the maintenance timing of
each compressor from the average value of the effective load
calculated in the effective load calculation unit 36 in an
operation time. In the present embodiment, the operation time is
assumed to be the operation time of the compressed gas supply unit
10A from the time point of start of the operation after the
previous maintenance to the time point of the calculation. However,
in the present invention, the operation time is not limited thereto
and other times may be set as the operation time. The average value
is calculated with the stop time of each compressor included, and
the average value is calculated for each compressor. Alternatively,
the average value of the four compressors may also be calculated
instead of calculating the average value for each compressor.
[0046] A monitoring device 40 is provided in the monitoring room or
the like. To the monitoring device 40, the detection signal of each
sensor is sent from the controller 34, and the determination result
of the determination unit 35, the effective load of each compressor
calculated in the effective load calculation unit 36, and the
signal indicative of the next maintenance timing estimated in the
estimation unit 37 are also sent. The monitoring device 40 includes
a display unit 42 and an alarm device 44. The display unit 42
displays the detected value of each sensor, the determination
result of the determination unit 35, the effective load calculated
in the effective load calculation unit 36, and the next maintenance
timing estimated in the estimation unit 37.
[0047] The controller 34 performs an operation in which control of
the number of compressors which minimizes the number of compressors
under operating condition with respect to the load of the
compressed gas supply unit 10A and an equal load operation which
controls the inverters 22a to 22d of the individual compressors 14a
to 14d based on the effective loads of the individual compressors
calculated in the effective load calculation unit 36 such that the
loads of the compressors 14a to 14d are equalized, are used in
combination. In addition, when the determination result of the
determination unit 35 indicates the presence of the abnormality,
the alarm device 44 issues an alarm. Further, an operator performs
the maintenance based on the next maintenance timing displayed in
the display unit 42.
[0048] According to the present embodiment, since the determination
unit 35 of the controller 34 determines the presence or absence of
the abnormality of each compressor based on the difference .DELTA.T
between the temperature around the compressors 14a to 14d and the
compressed gas temperature of the compression chamber of each of
the compressors 14a to 14d, it becomes possible to perform accurate
abnormality determination without the influence of the air
temperature. In addition, since the temperature sensor is used, it
is possible to make the apparatus configuration relatively simple
and make its cost lower.
[0049] In addition, since the effective load of each of the
compressors 14a to 14d is calculated from the correlation map shown
in FIG. 2 in the effective load calculation unit 36 of the
controller 34, it is possible to calculate the accurate effective
load. Further, since the controller 34 performs the operation in
which the control of the number of compressors and the equal load
operation are used in combination, energy saving is made possible.
Furthermore, with the equal load operation, it is possible to
eliminate an irregularity in the maintenance timing of the
compressor and reduce the maintenance frequency of the entire
compressed gas supply unit, whereby it is possible to save the
maintenance cost and improve the utilization rate of the compressed
gas supply unit.
[0050] In addition, since there are provided the inverters 22a to
22d which can control the RPMs of the compressors 14a to 14d
individually, the load control of each compressor is facilitated.
In the present embodiment, although the controller 34 and the
monitoring device 40 are separately provided, an integrated
monitoring controller having these functions may also be used
instead.
[0051] Although the effective loads of the compressors 14a to 14d
are calculated from the detected values of the pressure sensor 28
and the power sensors 26a to 26d in the present embodiment, the
pressure of the discharged gas of each of the compressors 14a to
14d may be detected instead, and when the difference between the
detected value of the pressure sensor 28 and the detected value of
the pressure of the discharged gas of the compressor exceeds a
threshold, it may be determined that the corresponding compressor
is abnormal. With this, it becomes possible to perform accurate
determination without the influence of the internal pressure of the
storage tank 12.
Second Embodiment
[0052] Next, a second embodiment of each of the apparatus of the
first aspect of the present invention and the method of the first
aspect of the present invention will be described with reference to
FIG. 3. A two-stage compressor 50 constituting a compressed gas
supply unit 10B of the present embodiment includes a low-pressure
side compressor 52 and a high-pressure side compressor 54. That is,
the low-pressure side compressor 52 and the high-pressure side
compressor 54 are driven by a shared rotating shaft 58, and the
rotating shaft 58 is driven by a drive motor 56. Gas discharged
from the low-pressure side compressor 52 is supplied to the
high-pressure side compressor 54 via an intermediate discharge path
60, further compressed in the high-pressure side compressor 54, and
sent to the storage tank (not shown). The RPM of the drive motor 56
can be steplessly adjusted by an inverter 62.
[0053] The intermediate discharge path 60 is provided with a
temperature sensor 64 which detects the temperature of the
intermediate discharge path 60, and the drive motor 56 is provided
with a power sensor 66 which detects the power consumption of the
drive motor 56. The detection signals of these sensors are sent to
the monitoring device 40, and the inverter 62 is controlled by the
controller 34. The configuration of the compressed gas supply unit
10B is otherwise the same as that of the first embodiment.
[0054] In the two-stage compressor 50, when an abrasion or the like
progresses in a portion constituting the compression chamber,
high-pressure air of the high-pressure side compressor 54 may flow
backward to the low-pressure side compressor 52 through the
intermediate discharge path 60. According to the present
embodiment, the temperature of the intermediate discharge path 60
is detected as the operation temperature of the two-stage
compressor 50, and hence it is possible to detect the presence or
absence of the backward flow of the high-pressure air. With this,
it is possible to accurately grasp the progress of fatigue of the
two-stage compressor 50, and hence it is possible to accurately
grasp the maintenance timing of the two-stage compressor 50.
[0055] Note that, in the present embodiment as well, instead of the
temperature of the intermediate discharge path 60, the pressure of
the discharge air of the intermediate discharge path 60 may be
detected, and when the difference between the pressure of the
discharge air and the internal pressure of the storage tank 12
exceeds a threshold, it may be determined that the compressor is
abnormal. With this, it becomes possible to perform the accurate
determination without the influence of the internal pressure of the
storage tank 12.
Third Embodiment
[0056] Next, an embodiment of each of an apparatus of a second
aspect of the present invention and a method of a second aspect of
the present invention will be described with reference to FIG. 4. A
compressed gas supply apparatus 70 of the present embodiment
includes a plurality of compressed gas supply units 10A, 10B, and
10C provided at positions apart from each other and a central
control unit 72 which can remotely control the compressed gas
supply units. Each of the compressed gas supply units 10A and 10C
has the same configuration as that of the compressed gas supply
unit 10A of the first embodiment, and the compressed gas supply
unit 10B has the same configuration as that of the compressed gas
supply unit 10B of the second embodiment.
[0057] The compressed gas supply unit 10A and the central control
unit 72 are provided with transmitter-receivers 74 and 80
respectively. The compressed gas supply unit 10A and the central
control unit 72 can perform data communication therebetween by
means of a data communication network 82 of a wireless access
system provided by a cellular phone carrier. The central control
unit 72 and the compressed gas supply unit 10B or 10C can also
perform the data communication therebetween by means of the same
wireless access system. Data such as detected values and the like
held by the monitoring device 40 of each compressed gas supply unit
is sent to the central control unit 72 through the data
communication network 82.
[0058] The central control unit 72 has a storage unit 76 and a
correction unit 78. The detected values of the temperature sensors
24a to 24d and 32 received from the compressed gas supply units
10A, 10B, and 10C are stored in the storage unit 76. In the
correction unit 78, the threshold .DELTA.Ts related to the
difference .DELTA.T between the detected value of the temperature
sensor 32 and the detected value of each of the temperature sensors
24a to 24d is corrected based on the detected values stored in the
storage unit 76 and the result of the actual abnormality occurrence
of the compressor. The result of the actual abnormality occurrence
of the compressor mentioned herein means data obtained when the
operator visually identifies the abnormality, and the operator
inputs the threshold .DELTA.Ts at the time of the identification in
the central control unit 72.
[0059] The central control unit 72 controls the operation of each
compressed gas supply unit based on the successively corrected
threshold .DELTA.Ts during the operation of the compressed gas
supply apparatus 70. Note that the monitoring device 40 of each
compressed gas supply unit and the central control unit 72 may be
accessed from a cellular phone 84 held by the operator via the data
communication network 82. That is, the operation state of each
compressed gas supply unit may be monitored by receiving data from
the central control unit 72 and the monitoring device 40 of each
compressed gas supply unit by means of the cellular phone 84.
[0060] According to the present embodiment, in addition to the
operation and effect obtained in the first embodiment of each of
the method of the first aspect of the present invention and the
apparatus of the first aspect of the present invention, by
successively correcting the threshold .DELTA.Ts of each compressed
gas supply unit in conjunction with watching the result of the
actual abnormality occurrence of the compressor, it is possible to
accurately determine the presence or absence of the abnormality of
the compressor. In addition, the presence or absence of the
abnormality of the compressor is determined based on a population
of the high detected values collected from the plurality of
compressed gas supply units, and hence it becomes possible to
perform the accurate determination.
Fourth Embodiment
[0061] Next, an embodiment of an apparatus of a third aspect of the
present invention will be described with reference to FIG. 5. A
compressed gas supply apparatus 90 of the present embodiment
includes two compressed gas supply units 10D and 10E and a central
control unit 92 which controls the operation of the compressed gas
supply units 10D and 10E. The compressed gas supply unit 10D
includes a storage tank 100, four compressors 102a to 102d, a
pressure sensor 104 which detects the internal pressure of the
storage tank 100, and a compressed gas supply pipe 106 which
supplies compressed gas in the storage tank 100 to a gas recipient
108.
[0062] The compressed gas supply unit 10E includes a storage tank
110, four compressors 112a to 112d, a pressure sensor 114 which
detects the internal pressure of the storage tank 110, and a
compressed gas supply pipe 116 which supplies the compressed gas in
the storage tank 110 to a gas recipient 118. Each of the compressed
gas supply units 10D and 10E has the same configuration as that of
the compressed gas supply unit 10A of FIG. 1. The compressed gas
supply pipe 106 and the compressed gas supply pipe 116 are
connected to each other by a connection pipe 96. The connection
pipe 96 is provided with an on-off valve 98.
[0063] As in the above embodiment, the data communication can be
performed between the central control unit 92 and the compressed
gas supply unit 10D or 10E or the on-off valve 98 by means of data
communication networks 94 of the wireless access system.
[0064] In the present embodiment, the opening/closing operation of
the on-off valve 98 is controlled by the central control unit 92.
For example, in a case where the compressed gas is supplied to the
gas recipient 108 and the internal pressure P.sub.1 of the storage
tank 100>the internal pressure P.sub.2 of the storage tank 110
is satisfied, it is possible to supply the compressed gas in the
storage tank 100 to the gas recipient 118 by opening the on-off
valve 98. In this manner, it is possible to monitor the internal
pressure P.sub.1 of the storage tank 100 and the internal pressure
P.sub.2 of the storage tank 110 by using the central control unit
92 to send the compressed gas of the compressed gas-supply unit 10D
or 10E to the gas recipient of the other compressed gas supply
apparatus, whereby it is possible to efficiently supply the
compressed gas to the plurality of gas recipients 108 and 118.
[0065] The present invention allows the energy-saving operation and
the maintenance cost reduction of a compressed gas supply unit
including a plurality of compressors, and solves a security problem
and allows low-cost remote control in a compressed gas supply
apparatus including a plurality of the compressed gas supply
units.
* * * * *