CN101814768A - Fuel cell based standby power system - Google Patents
Fuel cell based standby power system Download PDFInfo
- Publication number
- CN101814768A CN101814768A CN 201010121996 CN201010121996A CN101814768A CN 101814768 A CN101814768 A CN 101814768A CN 201010121996 CN201010121996 CN 201010121996 CN 201010121996 A CN201010121996 A CN 201010121996A CN 101814768 A CN101814768 A CN 101814768A
- Authority
- CN
- China
- Prior art keywords
- fuel cell
- converter
- control unit
- standby power
- hydrogen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Fuel Cell (AREA)
Abstract
The invention discloses a fuel cell based standby power system, which comprises a fuel cell system, a DC/DC converter, an auxiliary power supply device and a control system. The fuel cell system comprises a hydrogen supply system, an air supply system and a water circulating system which are respectively connected with a fuel cell stack, and the fuel cell stack is provided with a power output end; the DC/DC converter is connected with the power output end; the auxiliary power supply device is connected with the DC/DC converter in parallel and is then connected with electrical equipment; and the control system comprises a system control unit with a human-computer interface, the system control unit is respectively coupled with a battery management system, a hydrogen management system and a fuel cell control unit, and the fuel cell control unit is respectively coupled with the DC/DC converter and a single monitoring unit. The fuel cell based standby power system provided by the invention overcomes the defects of the battery and can conveniently supply power to equipment.
Description
Technical field
The present invention relates to a kind of standby power system based on fuel cell.
Background technology
Along with the progress of society and the raising of living standards of the people, supply of electric power has become indispensable key factor in production and the life, particularly seems particularly outstanding in some government function mechanisms and signal centre.Because some uncontrollable factors artificial or nature might make some period, certain panel region electric power occurs and supplies with forfeiture, so stand-by power supply is absolutely necessary.At present domestic communication base station mainly is that its initial investment is lower with lead acid accumulator power supply in support, but shortcoming is very outstanding: the maintenance and the management cost of storage battery are higher; Useful life is short; The restriction of capacity makes its stream time very limited, and long-time, stable electric energy output can not be provided; Cause environmental pollution easily.Fuel cell technology be generally acknowledge can replace the most promising technology of storage battery as communications industry stand-by power supply.It can source clean, the energy conversion efficiency height, and to the control technology of fuel cell power generation also comparative maturity.But at present domestic do not have as yet with the ripe case of fuel cells applications in field stand-by power supplies such as communication systems, also is in the research and development experimental stage mostly, and system's power output is also less.
200910061032.1 in a kind of standby electrical power system of fuel cell for communication has been proposed, but it does not make more detailed elaboration to its concrete case study on implementation, the characteristic of its application and the test status of system are also described; Its outage judges that so need increase different power-fail detection circuits in the system outside at different power consumption equipments, ease for use and versatility have certain deficiency by directly the detection of civil power being obtained; Its data communication is all transmitted in single CAN communication network, and when data volume was big, system real time was difficult to be guaranteed, and is unfavorable for the expansion of multisystem.
Summary of the invention
In order to solve the problems referred to above that prior art exists, the present invention proposes a kind of standby power system based on fuel cell, this system with hydrogen as the main energy, clean and effective; System can provide long-time stable, powerful direct current supply for external loading under the situation of civil power power down; System realizes judgement to outside civil power state by the monitoring to internal bus state and auxiliary power supply operating state, and ease for use and highly versatile have the feature of plug and play; System has adopted multichannel CAN communication network, and in conjunction with RS485, and the control monitoring means of system's different levels is adopted different data transmission channels, helps improving the expansion of the data-handling capacity and the system of system.
The present invention can be solved by the following technical programs:
A kind of standby power system based on fuel cell, it comprises a fuel cell system, and it comprises hydrogen supply system, air supply system, the water circulation system that links to each other with a fuel cell pack respectively, and described fuel cell pack is established an electric energy output end; One DC/DC converter, it links to each other with described electric energy output end; One auxiliary power supply, its with the parallel connection of described DC/DC converter after be connected with power consumption equipment; One control system, comprise the system control unit that is provided with man-machine interface, realize communication by RS485 between the two, this system control unit is linked with a battery management system, a hydrogen management system and a Fuel Cell Control unit respectively, realize communication by the CANA network between each unit, this Fuel Cell Control unit is linked with a described DC/DC converter and a monomer monitoring unit respectively, realizes communication by the CANAS network between each unit.The fuel cell system output is connected with voltage sensor, current sensor, realizing the status monitoring to fuel cell system, and connects fuse and diode as protective device; Auxiliary power supply and DC/DC converter output in parallel is connected to voltage sensor, to realize the real-time monitoring to system's output voltage; The auxiliary power supply output is connected to current sensor, its operating state of real-time diagnosis, and cooperate the busbar voltage state variation to obtain the power supply state of outside civil power, realized the internal judgment of external power source state.
Hydrogen supply of the present invention system comprises a hydrogen cylinder, and its efferent duct links to each other with described fuel cell pack by pressure sensor, temperature sensor and control valve successively; Described air supply system comprises a blower fan, and it links to each other with described fuel cell pack by a humidifier, and described blower fan also connects a controller of fan; Communicate by CANA between described system control unit and described battery management system, hydrogen management system and Fuel Cell Control unit, communicate by CANAS between described fuel control unit and DC converter and monomer monitoring unit.
By above-described technical scheme, a kind of standby power system of the present invention based on fuel cell, can utilize hydrogen as main fuel, galvanic current is pressed between output 44V-54V, can provide the single module net power output to reach the supply of electrical energy of 5kW in a long time, and can expand according to the actual requirements, to satisfy particular requirement, satisfy present communication base station etc. with the basic demand of equipment to stand-by power supply than large power-consuming equipment; This standby power system is independent fully, and the judgement of external power source state also realizes in internal system, and power supply interface externally only is provided, and has the feature of plug and play.
Description of drawings
Fig. 1 is the schematic diagram of a kind of standby power system based on fuel cell of the present invention and the interface of external equipment
1, fuel cell system; 2, the DC/DC converter; 3, auxiliary power supply; 4, power supply; 5, power consumption equipment
Fig. 2 is the internal structure of fuel cell system of the present invention
101, fuel cell pack; 102, hydrogen cylinder; 103, electromagnetically operated valve; 104, proportioning valve; 105, proportional control valve; 106, row's hydrogen electromagnetically operated valve; 108, hydrogen outlet; 109, humidifier; 110, blower fan; 111, controller of fan; 112, radiator; 113, water tank; 114, water pump; 115, air outlet slit; 116, electric energy output end
Fig. 3 is the topological structure of control system of the present invention
601, system control unit SCU; 602, man-machine interface HMI; 603, battery management system BMS; 604, hydrogen management system HMS; 605, Fuel Cell Control unit F CU; 606, monomer monitoring unit CVM, 607, extendible Fuel Cell Control unit
Embodiment
Below in conjunction with embodiment, further set forth the present invention:
A kind of standby power system based on fuel cell, it comprises fuel cell system 1, it comprises the hydrogen supply system, air supply system, water circulation system, those systems link to each other with fuel cell pack respectively, and fuel cell pack is established electric energy output end; One DC/DC converter 2, it is connected with electric energy output end; One auxiliary power supply 3 is connected with power consumption equipment 5 in the lump with the DC/DC converter; Also comprise a control system, it is divided into three layers, ground floor is a system control unit, it is provided with a man-machine interface, the second layer comprises a battery management system, a hydrogen management system and a Fuel Cell Control System, ground floor is realized communication by RS485, those systems of the second layer communicate by CANA with system control unit respectively and link, the 3rd layer comprises a DC/DC and a monomer monitoring unit, and DC/DC and monomer monitoring unit are respectively by CANAS communication network and Fuel Cell Control cell link.
As shown in Figure 1, a kind of standby power system based on fuel cell is mainly by fuel cell system 1, DC/DC converter 2, auxiliary power supply 3 (batteries) and control system thereof constitute, and be connected with voltage sensor, current sensor at fuel cell system 1 output, realizing status monitoring, and connect fuse and diode as protective device to fuel cell system; Auxiliary power supply 3 and DC/DC converter 2 outputs in parallel are connected to voltage sensor, to realize the real-time monitoring to system's output voltage; Auxiliary power supply 3 outputs are connected to current sensor, its operating state of real-time diagnosis, and cooperate the busbar voltage state variation to obtain the power supply state of outside civil power, and realized the internal judgment of external power source state, the output of DC/DC converter 2 is connected with fuse and diode.When external power source 4 normal operations, by civil power directly electricity supply and use equipment use after changing; When external power source 4 quit work, as main supply of electrical energy source, the electric energy of its output was converted to the stable DC voltage that is suitable for external electric equipment behind DC/DC converter 2 by backup power system of fuel cell 1; After outside city power recovery was normal, backup power system of fuel cell 1 was out of service, was the power consumption equipment power supply by external power source 4.Auxiliary power supply 3 (batteries) has guaranteed the uninterrupted power supply continual and steady to power consumption equipment as the energy snubber device in the system mode transfer process.
As shown in Figure 2, the internal structure of fuel cell system of the present invention, this fuel cell system is made of the hydrogen supply system, air supply system, the water circulation system that link to each other with fuel cell pack 101 respectively, wherein the hydrogen supply system comprises hydrogen cylinder 102, connect pressure sensor successively, temperature sensor, and electromagnetically operated valve 103, proportioning valve 104, proportional control valve 105, final access fuel cell pack 101, and be provided with hydrogen outlet 108, the row's of being provided with hydrogen electromagnetically operated valve 106 between inlet pipeline and outlet conduit.Air supply system is a controller of fan 111 control connections one blower fans 110, and links to each other with fuel cell pack 101 by a humidifier 109, for it provides air; Water circulation system is that a water pump 114 is connected with water tank 113, connects and fuel cell pack 102 by a radiator 112, and this fuel cell pack 101 is provided with air outlet slit 115 and electric energy output end 116.When fuel cell system was in running status, the high pressure hydrogen in the hydrogen cylinder 103 entered fuel cell pack 101 after the multiple valve step-down, produced electric energy with the air generation electrochemical reaction that enters fuel cell pack 101 through blower fan 110.Water pump 114 is kept the normal operation of cooling water recirculation system, and keep entering the cooling water temperature of fuel cell pack 101 by radiator 112 can be not too high; Remaining hydrogen and air are discharged from hydrogen outlet 108 and air outlet slit 115 respectively after the generation electrochemical reaction, and electric energy output end 116 exports DC/DC transducer 2 backs to and is external electric equipment 5 power supplies.Also have temperature sensor in the system, parts such as pressure sensor come the real-time monitoring system state.
As shown in Figure 3, topological structure for control system of the present invention, it is divided into three layers, ground floor is a system control unit SCU601, and link to each other with a man-machine interface HMI602, the second layer comprises a battery management system BMS603, an one hydrogen management system HMS604 and a Fuel Cell Control System FCU605, those systems of the second layer pass through the CANA communication linkage with system control unit 601 respectively, the 3rd layer comprises a DC/DC converter 2 and a monomer monitoring unit CVM606, and DC/DC converter 2 and monomer monitoring unit CVM606 link with Fuel Cell Control unit F CU605 by the CANAS communication network respectively.This control system also comprises the Fuel Cell Control unit 607 that can expand.
The fuel cell pack 101 single module net power outputs that native system is selected for use are 7.5kW-8.5kW, and the main Blast Furnace Top Gas Recovery Turbine Unit (TRT) in the battery system that acts as a fuel is servicing unit 3 power supplies of power consumption equipment 4 and fuel cell system inside.The rated power of the DC/DC converter of selecting for use 2 is 8.5kW, and the input voltage range of its support is: 55-120VDC, output voltage range is: 40-54VDC.Auxiliary power supply 3 is 80Ah by the single-unit capacity, and nominal voltage is that the 4 joint VALTA storage batterys of 12V are formed; Power supply 4 is output as electric for be converted to the galvanic current pressure through civil power; Load adopts fuel cell test with electronics load simulation external electric equipment 5, and is 5kW with its power setting.
But above-mentioned embodiment is exemplary, is to be the restriction that this patent is comprised scope in order better to make those skilled in the art can understand this patent, can not to be interpreted as; So long as according to spirit that this patent discloses done anyly be equal to change or modify, all fall into the scope that this patent comprises.
Claims (10)
1. the standby power system based on fuel cell is characterized in that: comprise
One fuel cell system, it comprises hydrogen supply system, air supply system, the water circulation system that links to each other with a fuel cell pack respectively, described fuel cell pack is established an electric energy output end;
One DC/DC converter, it links to each other with described electric energy output end;
One auxiliary power supply, its with the parallel connection of described DC/DC converter after be connected with power consumption equipment;
One control system, comprise the system control unit that is provided with man-machine interface, this system control unit is linked with a battery management system, a hydrogen management system and a Fuel Cell Control unit respectively, and this Fuel Cell Control unit is linked with a described DC/DC converter and a monomer monitoring unit respectively.
2. a kind of standby power system based on fuel cell according to claim 1 is characterized in that: a voltage sensor in parallel between the electric energy output end of described fuel cell system and the DC/DC converter.
3. a kind of standby power system based on fuel cell according to claim 2 is characterized in that: series connection one current sensor between the electric energy output end of described fuel cell and the DC/DC/ converter.
4. a kind of standby power system based on fuel cell according to claim 3 is characterized in that: be in series with fuse and diode between the electric energy output end of described fuel cell and the DC/DC converter.
5. according to claim 1 or 4 described a kind of standby power systems based on fuel cell, it is characterized in that: described auxiliary power supply and DC/DC converter output in parallel is connected to voltage sensor.
6. a kind of standby power system based on fuel cell according to claim 5 is characterized in that: connect a current sensor between described auxiliary power supply output and the power consumption equipment.
7. a kind of standby power system based on fuel cell according to claim 6 is characterized in that: be connected with fuse and diode between the output of described DC/DC converter and the power consumption equipment.
8. a kind of standby power system according to claim 1 based on fuel cell, it is characterized in that: described hydrogen supply system comprises a hydrogen cylinder, and its efferent duct links to each other with described fuel cell pack by pressure sensor, temperature sensor and control valve successively.
9. a kind of standby power system according to claim 1 based on fuel cell, it is characterized in that: described air supply system comprises a blower fan, and it links to each other with described fuel cell pack by a humidifier, and described blower fan also connects a controller of fan.
10. a kind of standby power system according to claim 1 based on fuel cell, it is characterized in that: communicate by RS485 between described system control unit and the man-machine interface, communicate by CANA between described system control unit and described battery management system, hydrogen management system and Fuel Cell Control unit, communicate by CANAS between described fuel control unit and DC converter and monomer monitoring unit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN 201010121996 CN101814768A (en) | 2010-03-11 | 2010-03-11 | Fuel cell based standby power system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN 201010121996 CN101814768A (en) | 2010-03-11 | 2010-03-11 | Fuel cell based standby power system |
Publications (1)
Publication Number | Publication Date |
---|---|
CN101814768A true CN101814768A (en) | 2010-08-25 |
Family
ID=42621917
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN 201010121996 Pending CN101814768A (en) | 2010-03-11 | 2010-03-11 | Fuel cell based standby power system |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN101814768A (en) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102594890A (en) * | 2012-02-17 | 2012-07-18 | 昆山弗尔赛能源有限公司 | Multifunctional remote monitoring system for fuel cell standby power supply |
CN102810901A (en) * | 2012-07-30 | 2012-12-05 | 西南交通大学 | Communication power supply system based on fuel cell |
CN103078124A (en) * | 2012-12-28 | 2013-05-01 | 新源动力股份有限公司 | Output control system for fuel battery emergency electric power source startup and control method |
CN103248082A (en) * | 2012-02-14 | 2013-08-14 | 江苏华源氢能科技发展有限公司 | Fuel cell standby power supply system provided with hydrogen circulation device |
CN103245922A (en) * | 2013-03-28 | 2013-08-14 | 昆山弗尔赛能源有限公司 | Fuel cell stand-by power supply system intelligentized test platform |
CN103390930A (en) * | 2012-05-07 | 2013-11-13 | 中兴电工机械股份有限公司 | Electric power system control method of fuel cells |
CN104393626A (en) * | 2014-07-16 | 2015-03-04 | 苏州华清京昆新能源科技有限公司 | Distributed solid oxide fuel cell charging station |
CN104485711A (en) * | 2014-12-25 | 2015-04-01 | 苏州华清京昆新能源科技有限公司 | Liquefied petroleum gas solid oxide fuel cell charging station |
CN104681829A (en) * | 2013-12-02 | 2015-06-03 | 陕西荣基实业有限公司 | Hydrogen fuel cell for communication base station |
CN105048594A (en) * | 2015-08-26 | 2015-11-11 | 苏州弗尔赛能源科技股份有限公司 | Fuel cell based portable automatic charging system of unmanned aerial vehicle |
CN105977560A (en) * | 2016-07-22 | 2016-09-28 | 珠海银通农业科技有限公司 | Fuel cell system used in unmanned aerial vehicle |
CN109103981A (en) * | 2018-08-30 | 2018-12-28 | 广东国鸿氢能科技有限公司 | A kind of fuel cell emergency power supply control system and control method |
CN110601344A (en) * | 2019-09-02 | 2019-12-20 | 北京航天发射技术研究所 | Fuel cell energy management system for base station standby power supply |
CN113130959A (en) * | 2021-03-31 | 2021-07-16 | 江苏科技大学 | Boat fuel cell power system and working method thereof |
CN113193645A (en) * | 2021-04-22 | 2021-07-30 | 四川荣创新能动力系统有限公司 | Control method of hydrogen fuel cell emergency power supply system |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN2914456Y (en) * | 2006-05-11 | 2007-06-20 | 广东中玉科技有限公司 | Stand-by power supply based on fuel cell |
JP2007228728A (en) * | 2006-02-23 | 2007-09-06 | Nippon Oil Corp | Emergency power system using fuel cell |
CN101505092A (en) * | 2009-03-09 | 2009-08-12 | 武汉理工大学 | Standby electrical power system of fuel cell for communication |
-
2010
- 2010-03-11 CN CN 201010121996 patent/CN101814768A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007228728A (en) * | 2006-02-23 | 2007-09-06 | Nippon Oil Corp | Emergency power system using fuel cell |
CN2914456Y (en) * | 2006-05-11 | 2007-06-20 | 广东中玉科技有限公司 | Stand-by power supply based on fuel cell |
CN101505092A (en) * | 2009-03-09 | 2009-08-12 | 武汉理工大学 | Standby electrical power system of fuel cell for communication |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103248082A (en) * | 2012-02-14 | 2013-08-14 | 江苏华源氢能科技发展有限公司 | Fuel cell standby power supply system provided with hydrogen circulation device |
CN102594890A (en) * | 2012-02-17 | 2012-07-18 | 昆山弗尔赛能源有限公司 | Multifunctional remote monitoring system for fuel cell standby power supply |
CN103390930A (en) * | 2012-05-07 | 2013-11-13 | 中兴电工机械股份有限公司 | Electric power system control method of fuel cells |
CN102810901A (en) * | 2012-07-30 | 2012-12-05 | 西南交通大学 | Communication power supply system based on fuel cell |
CN103078124A (en) * | 2012-12-28 | 2013-05-01 | 新源动力股份有限公司 | Output control system for fuel battery emergency electric power source startup and control method |
CN103245922A (en) * | 2013-03-28 | 2013-08-14 | 昆山弗尔赛能源有限公司 | Fuel cell stand-by power supply system intelligentized test platform |
CN104681829A (en) * | 2013-12-02 | 2015-06-03 | 陕西荣基实业有限公司 | Hydrogen fuel cell for communication base station |
CN104393626A (en) * | 2014-07-16 | 2015-03-04 | 苏州华清京昆新能源科技有限公司 | Distributed solid oxide fuel cell charging station |
CN104485711A (en) * | 2014-12-25 | 2015-04-01 | 苏州华清京昆新能源科技有限公司 | Liquefied petroleum gas solid oxide fuel cell charging station |
CN105048594A (en) * | 2015-08-26 | 2015-11-11 | 苏州弗尔赛能源科技股份有限公司 | Fuel cell based portable automatic charging system of unmanned aerial vehicle |
CN105977560A (en) * | 2016-07-22 | 2016-09-28 | 珠海银通农业科技有限公司 | Fuel cell system used in unmanned aerial vehicle |
CN109103981A (en) * | 2018-08-30 | 2018-12-28 | 广东国鸿氢能科技有限公司 | A kind of fuel cell emergency power supply control system and control method |
CN110601344A (en) * | 2019-09-02 | 2019-12-20 | 北京航天发射技术研究所 | Fuel cell energy management system for base station standby power supply |
CN110601344B (en) * | 2019-09-02 | 2021-11-09 | 北京航天发射技术研究所 | Fuel cell energy management system for base station standby power supply |
CN113130959A (en) * | 2021-03-31 | 2021-07-16 | 江苏科技大学 | Boat fuel cell power system and working method thereof |
CN113130959B (en) * | 2021-03-31 | 2022-05-13 | 江苏科技大学 | Boat fuel cell power system and working method thereof |
CN113193645A (en) * | 2021-04-22 | 2021-07-30 | 四川荣创新能动力系统有限公司 | Control method of hydrogen fuel cell emergency power supply system |
CN113193645B (en) * | 2021-04-22 | 2022-08-09 | 四川荣创新能动力系统有限公司 | Control method of hydrogen fuel cell emergency power supply system |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN101814768A (en) | Fuel cell based standby power system | |
CN101917026B (en) | Fuel battery-based emergency power generation vehicle | |
CN201821261U (en) | Backup power supply system based on fuel battery | |
CN202488178U (en) | Photovoltaic energy storage electric vehicle charging station system based on direct current bus | |
CN107579296B (en) | Lithium battery dynamic power system and vehicle | |
CN202712873U (en) | Intelligent household solar control inverter | |
CN113675952A (en) | Multi-element energy storage fusion control terminal and control system thereof | |
CN103066679A (en) | Universal communication base station solar and wind energy centralized power supply system and control method thereof | |
CN204497336U (en) | Multikilowatt fuel cell lithium ion battery hybrid power device | |
CN116799844B (en) | Portable distributed energy storage system | |
CN109103981A (en) | A kind of fuel cell emergency power supply control system and control method | |
CN111082413A (en) | Urban community full-direct-current micro-grid and control system thereof | |
CN108736518B (en) | Comprehensive energy supply system and method for urban complex and large public building group | |
CN111381174A (en) | Fuel cell test and lithium ion battery formation capacity-sharing coupling system and method | |
CN111404248A (en) | Micro-grid system and method based on coupling of fuel cell test and charging pile | |
CN111381172A (en) | Micro-grid-based battery testing and formation-capacitance-grading coupling system and control method | |
CN209803301U (en) | Micro-grid system based on fuel cell test | |
CN218771422U (en) | Modular green electricity hydrogen production storage control system | |
CN203312895U (en) | Universal type communication base station solar energy and wind energy centralized power supply system | |
CN116819355A (en) | Energy-saving test system for direct-current bus of micro-grid at rear section of battery cell | |
CN214898524U (en) | Photovoltaic energy supply system based on renewable fuel cell | |
CN212950158U (en) | Integrated electric energy conversion device, power supply device, vehicle and equipment | |
CN102969754B (en) | Storage battery pack connection circuit and intelligent storage battery pack | |
Conte et al. | Design procedures of lithium-ion battery systems: The application to a cable railway | |
CN217425976U (en) | Container energy storage system communication framework |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20100825 |