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.

What is claimed is: 
     
         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.