JP2008097832A - Interior drying preventing device of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent drying of a polymer solid electrolyte membrane when a fuel cell is stopped for a long period. <P>SOLUTION: This is an interior drying preventing device in which a water flow passage 19 and an oxidizer gas flow passage 18, or a fuel gas flow passage 16 are arranged via porous separators 17, 20 and in which interior drying of the fuel cell 10 is prevented. This is equipped with a water tank 401 to store water supplied to the water flow passage 19, a water piping 402 to connect the water tank 401 and the water flow passage 19, a water supplying means 401 to supply water of the water tank 401 to the water flow passage 19 via the water piping 402, a water retaining means 408 to retain the water supplied to the water flow passage 19 in the water flow passage 19, and a water supply amount adjusting means 403 to adjust the supply amount of water by the water supplying means 401 while the fuel cell 100 is stopped. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal drying prevention device for a fuel cell.

  A fuel cell generates electricity by sandwiching an electrolyte membrane between a fuel electrode and an oxidant electrode and supplying fuel gas to the fuel electrode and oxidant gas to the oxidant electrode. For example, in an automobile application, a polymer solid electrolyte membrane having hydrogen ion conductivity is generally often used as an electrolyte membrane. Further, when hydrogen is supplied as the fuel gas and air is supplied as the oxidant gas to the fuel cell, the following reaction occurs.

Fuel electrode: 2H ₂ → 4H ⁺ + 4e ⁻ (1)
Oxidant electrode: O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)
Therefore, since the fuel cell only discharges water as a by-product, there is an advantage that a substance that damages the global environment such as carbon dioxide as in an internal combustion engine is not released.

  By the way, in order for the fuel cell to generate power efficiently, it is necessary to increase the conductivity of the polymer solid electrolyte membrane and reduce the resistance when electrons generated by the reaction move. For that purpose, the polymer solid electrolyte membrane needs to be appropriately humidified.

Therefore, the conventional internal dry prevention device of a fuel cell includes a moisture permeable humidifier that humidifies dry water after the reaction with moisture in the off gas between the dry air supply path and the off gas discharge path. It was. The dry air supply path and the off-gas discharge path are configured so that a closed loop can be formed. When the fuel cell is stopped, the closed loop is formed.When the fuel cell is restarted, the closed loop is formed by the supercharger. After adjusting the dew point in the fuel cell by circulating air, a control device for releasing the closed loop and operating the fuel cell normally was provided (for example, see Patent Document 1).
JP 2001-216989 A

  However, in the above-described conventional fuel cell internal drying prevention device, for example, when the fuel cell is stopped for a long period of time, the fuel cell undergoes a temperature change, a pressure fluctuation, etc., so it is technically necessary to form a complete closed loop. Have difficulty. Therefore, there is a problem that it is difficult to prevent the polymer solid electrolyte membrane from being dried.

  The present invention has been made paying attention to such a conventional problem, and even when the fuel cell is stopped for a long time, the polymer solid electrolyte membrane is prevented from being dried and in an optimal state at the time of restart. An object of the present invention is to provide an internal drying prevention device for a fuel cell that can be operated.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention provides an interior of a fuel cell (100) in which a water channel (19) and an oxidant gas channel (18) or a fuel gas channel (16) are arranged via a porous separator (17, 20). An internal drying preventing device for a fuel cell that prevents water from drying, a water tank (401) for storing water supplied to the water flow path, and a water pipe (402) for connecting the water tank and the water flow path Water supply means (401, 431) for supplying water from the water tank to the water flow path via the water pipe, and water holding means (408) for holding the water supplied to the water flow path in the water flow path And a water supply amount adjusting means (403) that is provided in the water pipe and adjusts the amount of water supplied by the water supply means while the fuel cell is stopped.

  Drying of the solid polymer electrolyte membrane can be prevented when the fuel cell is stopped for a long period of time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of an internal drying prevention device 1 for a fuel cell according to a first embodiment of the present invention.

  The fuel cell internal drying prevention device 1 includes a fuel cell 100, an air supply mechanism 200, a hydrogen supply mechanism 300, a humidifier 400, and a controller 500.

  The fuel cell 100 generates power by reacting a fuel gas such as hydrogen with an oxidant gas such as oxygen in the air. The fuel cell 100 is configured by stacking a plurality of single cells 10. In addition, in order to understand easily, the longitudinal cross-section of the single cell 10 was described in FIG.

  The unit cell 10 includes a solid polymer electrolyte membrane (hereinafter referred to as “electrolyte membrane”) 11, an anode catalyst layer 12 and a cathode catalyst layer 13 that sandwich the electrolyte membrane 11, and anode gas diffusion provided outside the anode catalyst layer 12. A layer 14 and a cathode gas diffusion layer 15 provided outside the cathode catalyst layer 13.

  The single cell 10 is provided on the surface on the anode gas diffusion layer 14 side, and is provided on the anode separator 17 having the plurality of hydrogen flow paths 16 and the surface on the cathode gas diffusion layer 15 side. And a cathode separator 20 having a humidified water channel 19. The anode separator 17 and the cathode separator 20 are porous bodies. The anode separator 17 may be a solid body.

  In the present invention, the electrolyte membrane 11, the anode catalyst layer 12, the cathode catalyst layer 13, the anode gas diffusion layer 14, and the cathode gas diffusion layer 15 are composed of a membrane electrode assembly (MEA) (hereinafter referred to as “MEA”). 21 is configured.

  The air supply mechanism 200 supplies air as an oxidant gas to the air flow path 18 formed in the cathode separator 20 of the fuel cell 100. The air supply mechanism 200 includes a compressor 201, an air supply pipe 202, and an air control valve 203.

  The compressor 201 supplies pressurized air to the fuel cell 100 via the air supply pipe 202.

  The air supply pipe 202 connects the compressor 201 and the air flow path 18 of the fuel cell 100.

  The air control valve 203 is provided in the middle of the air supply pipe 202. The air control valve 203 adjusts the amount of air supplied to the air flow path 18. The air control valve 203 is controlled to be opened and closed by a controller 500 described later, and is opened during operation of the fuel cell 100. When the air control valve 203 is opened, air is supplied to the air flow path 18.

  The hydrogen supply mechanism 300 supplies hydrogen as fuel gas from a hydrogen tank (not shown) to the hydrogen flow path 16 formed in the anode separator 17 of the fuel cell 100.

  The humidifier 400 supplies humidified water to the fuel cell 100 and collects waste water discharged from the fuel cell 100. The humidifier 400 includes a humidified water tank 401, a humidified water supply pipe 402, a humidified water control valve 403, a drain pipe 404, a sub tank 405, a drain collection pipe 406, and a drain collection air supply pipe 407. .

  The humidified water tank 401 stores humidified water (pure water) for humidifying the MEA 21 of the fuel cell 100. The humidified water tank 401 is disposed at a position higher than the fuel cell 100 in order to supply humidified water to the fuel cell 100 by the head pressure.

  The humidified water supply pipe 402 connects the humidified water tank 401 and the humidified water channel 19 of the fuel cell 100.

  The humidified water control valve 403 is provided in the middle of the humidified water supply pipe 402. The humidified water control valve 403 adjusts the amount of humidified water supplied to the fuel cell 100. The humidifying water control valve 403 is a mechanical relief valve, and is normally closed, but opens when the pressure of the humidifying water supply pipe 402a between the humidifying water control valve 403 and the fuel cell 100 becomes a predetermined pressure or less.

  The drainage pipe 404 connects the air flow path 18 of the fuel cell 100 and the sub tank 405. A cathode off-gas containing water (water vapor) generated by the electrochemical reaction of the fuel cell 100 and air that has not been used in the chemical reaction flows through the drainage pipe 404. A drainage control valve 408 is disposed in the middle of the drainage pipe 404. The drainage control valve 408 is controlled to be opened and closed by a controller 500, which will be described later. The drainage control valve 408 is opened during the operation of the fuel cell 100, but is closed during the stop so as to retain moisture in the fuel cell 100.

  The sub tank 405 stores the condensed water contained in the cathode off gas.

  In the sub tank 405, in order to collect the stored water in the humidified water tank 401, a drain collecting pipe 406 connected to the humidified water tank 401 at one end and a drain collecting air supply pipe 407 connected to the air supplying pipe 202. And are connected. A drainage recovery air control valve 409 is disposed in the middle of the drainage recovery air supply pipe 407. The wastewater recovery air control valve 409 is controlled to be opened and closed by a controller 500, which will be described later, and is normally closed, but is opened during wastewater recovery.

  The controller 500 includes a CPU, a ROM, a RAM (not shown), and the like, and controls opening and closing of the electromagnetic valves of the air control valve 203, the drain control valve 408, and the drain recovery air control valve 409 described above.

  The air control valve 203 is opened during operation of the fuel cell 100, and sends compressed air from the compressor 201 to the fuel cell 100.

  The drainage control valve 408 is opened during operation of the fuel cell 100, and is closed during operation to keep moisture inside the fuel cell 100.

  The waste water recovery air control valve 409 is opened at the time of waste water recovery performed during operation of the fuel cell 100, and sends compressed air from the compressor 201 to the sub tank 405. Note that the air control valve 203 is closed during the drainage recovery.

  Next, the operation of the fuel cell internal drying prevention device 1 will be described.

  When restarting after stopping the operation of the fuel cell 100, if the MEA 21 is in a dry state, the ionic conductivity is lowered, so that the power generation efficiency of the fuel cell 100 is lowered. Therefore, the fuel cell internal drying prevention device 1 needs to humidify the MEA 21 and prevent the MEA 21 from drying even when the fuel cell 100 is stopped.

  However, while the fuel cell 100 is stopped, the hydrogen flow path 16 and the air flow path 18 of the fuel cell 100 are equivalent to atmospheric pressure. Therefore, if humidified water is continuously supplied while the fuel cell 100 is stopped, water may accumulate in the hydrogen channel 16 and the air channel 18. Then, when the fuel cell 100 is restarted, it becomes difficult for gas to flow, and the power generation efficiency of the fuel cell 100 decreases.

  Therefore, the fuel cell internal drying prevention device 1 keeps the water inside the fuel cell 100 by closing the drainage control valve 408 while the fuel cell 100 is stopped. Thereby, even when the fuel cell 100 is stopped, the water contained in the cathode separator 20 formed of the porous body is supplied to the MEA 21. Therefore, the internal dry prevention device 1 of the fuel cell can prevent the MEA 21 from drying while the fuel cell 100 is stopped.

  However, depending on the ambient temperature, the water retained in the fuel cell 100 may evaporate and become water vapor. It is difficult to prevent such water vapor from leaking from the inside of the fuel cell 100 to the outside air. Therefore, when the stop period of the fuel cell 100 is extended for a long time, all the water held in the fuel cell 100 may evaporate and the MEA 21 may be dried.

  Therefore, in the present embodiment, the humidifying water control valve 403 is a mechanical relief valve that opens when the pressure of the humidifying water supply pipe 402a becomes lower than a predetermined pressure and closes when the pressure becomes higher than the predetermined pressure. As a result, regardless of whether the fuel cell 100 is in operation or stopped, when the humidified water evaporates and the pressure of the humidified water supply pipe 402a becomes equal to or lower than a predetermined pressure, the humidified water control valve 403 opens and the humidified water is fueled. The battery 100 can be supplied. Therefore, the fuel cell internal drying prevention device 1 can humidify the MEA 21 even when the fuel cell 100 is stopped, and can prevent the MEA 21 from drying. Below, supply control of the humidification water by the internal dry prevention apparatus 1 of this fuel cell is demonstrated.

  During operation of the fuel cell 100, the fuel cell internal drying prevention device 1 opens the drainage control valve 408. When the pressure of the humidified water supply pipe 402a becomes equal to or lower than a predetermined pressure, the humidified water control valve 403 is opened, and humidified water is supplied from the humidified water tank 401 to the fuel cell 100. After the supply, when the pressure of the humidified water supply pipe 402a becomes a predetermined pressure or higher, the humidified water control valve 403 is closed.

  The humidified water supplied to the humidified water channel 19 of the fuel cell 100 is supplied from the humidified water channel 19 to the MEA 21 via the separator 20 formed of a porous body. At this time, since the MEA 21 generates heat in a power generation state, the supplied humidified water evaporates to become water vapor. By this water vapor, the fuel cell internal drying prevention device 1 cools the fuel cell 100 and humidifies the MEA 21.

  Note that when the humidified water supplied to the MEA 21 is evaporated and released to the outside air, the pressure of the humidified water supply pipe 402a gradually decreases. And when the pressure of the humidification water supply piping 402a becomes below a predetermined pressure, the humidification water control valve 403 opens again and humidification water is supplied to MEA21.

  Further, when the fuel cell 100 is stopped, the fuel cell internal drying prevention device 1 closes the drainage control valve 27. This is to keep moisture in the fuel cell 100 and prevent the MEA 21 from drying.

  Here, depending on the ambient temperature, when the fuel cell 100 is stopped, the water held in the fuel cell 100 evaporates to become water vapor, and this water vapor may leak from the inside of the fuel cell 100 to the outside air. If the water held inside the fuel cell 100 evaporates and leaks to the outside air, the MEA 21 dries accordingly. Further, the pressure of the humidified water supply pipe 402a also decreases accordingly. When the pressure of the humidified water supply pipe 402a becomes equal to or lower than a predetermined pressure, the humidified water control valve 403 is opened and humidified water is supplied to the MEA 21.

  Therefore, the internal dry prevention device 1 of the fuel cell can prevent the MEA 21 from drying even if the fuel cell 100 is stopped for a long period of time and the water retained in the fuel cell 100 evaporates.

  According to this embodiment described above, the humidifying water control valve 403 is provided which is a mechanical relief valve that opens when the pressure of the humidifying water supply pipe 402a becomes a predetermined pressure or less and closes when the pressure becomes a predetermined pressure or more. As a result, regardless of whether the fuel cell 100 is in operation or stopped, when the humidified water evaporates and the pressure of the humidified water supply pipe 402a falls below a predetermined pressure, the humidified water control valve 403 is automatically opened and humidified. Water can be supplied to the fuel cell 100. Therefore, drying of the MEA 21 can be prevented, and the fuel cell 100 can always be operated in an optimal humidified state.

  Further, the evaporated shortage of water can be supplied to the fuel cell 100 without consuming electric power. Therefore, the humidified water in the humidified water tank 401 can be used efficiently.

  Further, the water discharged as the waste water from the air flow path 18 is stored in the sub-tank 405 and is collected in the humidified water tank 401 using the pressure of the compressor 201, so that the humidified water can be efficiently used. Thus, the humidified water tank 401 can be downsized.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in that the humidifying water control valve 403 is an electromagnetic valve and a pressure sensor 421 is added to the humidifying water supply pipe 402a. Hereinafter, the difference will be mainly described. In each of the following embodiments, the same reference numerals are used for portions that perform the same functions as those of the first embodiment described above, and repeated descriptions are omitted as appropriate.

  FIG. 2 is a diagram showing a schematic configuration of the internal dry prevention device 2 of the fuel cell according to the second embodiment of the present invention.

  In this embodiment, the humidifying water control valve 403 is an electromagnetic valve, and the controller 500 controls the opening and closing of the humidifying water control valve 403 according to the pressure of the humidifying water supply pipe 402a. Therefore, the pressure sensor 421 is disposed in the humidified water supply pipe 402a.

  As a result, if power is supplied to the controller 500 and the pressure sensor 421, the pressure of the humidified water supply pipe 402a detected by the pressure sensor 421 becomes equal to or lower than a predetermined pressure even when the fuel cell 100 is stopped. In addition, the humidified water control valve 403 can be opened to supply humidified water to the fuel cell 100.

  According to this embodiment described above, in addition to the effects of the first embodiment, by using the pressure sensor 421, it is possible to accurately detect the drying of the MEA 21.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment is different from the second embodiment in that the humidified water tank 401 is not disposed at a position higher than the fuel cell 100. Hereinafter, the difference will be mainly described.

  FIG. 3 is a diagram showing a schematic configuration of the internal dry prevention device 3 of the fuel cell according to the third embodiment of the present invention.

  In this embodiment, since the humidified water tank 401 is not disposed at a position higher than the fuel cell 100, the humidified water cannot be supplied to the fuel cell 100 by the head pressure. Therefore, the pump 431 is disposed in the humidified water supply pipe 402 upstream from the humidified water control valve 403.

  As a result, the controller 500 drives the pump 431 and opens the humidified water control valve 403 when the pressure of the humidified water supply pipe 402a detected by the pressure sensor 421 becomes equal to or lower than a predetermined pressure. Humidified water can be supplied to the. Therefore, even when the humidified water tank 401 cannot be disposed at a position higher than the fuel cell 100, the humidified water can be stably supplied.

  According to the present embodiment described above, in addition to the effects of the second embodiment, it is not necessary to arrange the humidified water tank 401 at a position higher than the fuel cell 100, so that the degree of freedom in system design is improved. Further, since humidified water is supplied by the pump 431, stable humidified water can be supplied.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in that the humidifying water control valve 403 is a logic valve. Hereinafter, the difference will be mainly described.

  FIG. 4 is a diagram showing a schematic configuration of the internal dry prevention device 4 of the fuel cell according to the fourth embodiment of the present invention.

  In FIG. 4, the humidified water control valve 403 is a logic valve and is connected to a branch pipe 202 a that branches from the air supply pipe 202. The humidifying water control valve 403 is opened when the compressor 201 is operated and closed when the compressor 201 is stopped by the supercharging pressure of the compressor 201.

  The humidifying water supply pipe 402 is provided with a bypass passage 441 that bypasses the humidifying water control valve 403. The bypass passage 441 is provided with an orifice 442 that limits the flow rate of the humidified water flowing through the bypass passage 441. The orifice diameter is supplied via the bypass passage 441 in consideration of the amount of water vapor contained in the air leaking from the inside of the fuel cell 100 to the outside air while the fuel cell 100 is stopped, the head pressure from the humidified water tank 401, and the like. The amount of humidified water to be set is set to be approximately the same as the amount of water vapor leaking to the outside air.

  As a result, during operation of the fuel cell 100, the humidified water control valve 403 is opened, and humidified water is supplied to the fuel cell 100 via the humidified water supply pipe 402. On the other hand, when the fuel cell 100 is stopped, an appropriate amount of humidified water is supplied to the fuel cell 100 via the bypass passage 441.

  Therefore, even when the internal drying prevention device 4 of the fuel cell is stopped, the humidified water can be supplied without consuming electric power. During the operation of the fuel cell 100, the supply amount of the humidified water to the fuel cell 100 can be adjusted by the humidifying water control valve 403. During the stop, the orifice 442 of the bypass passage 441 supplies the humidified water to the fuel cell 100. The supply amount can be adjusted. That is, the amount of humidified water supplied to the fuel cell 100 can be set separately when the fuel cell 100 is in operation and when it is stopped.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, in the present invention, the humidified water channel 19 is provided in the cathode separator 20, but may be provided in the anode separator 17. In addition, the moisture may be retained inside the fuel cell 100 by making the humidified water flow path 19 dead end without using the drainage control valve 408. Further, by providing a valve such as a humidified water control valve in the vicinity of a heat source such as a stack end plate heater of the fuel cell 100, it is possible to quickly thaw even if it is frozen in a cold district.

  In the second and third embodiments, when the pressure sensor 421 is not used, timer control that repeats opening and closing of the humidified water control valve 403 at predetermined time intervals may be used. Thereby, drying of MEA 21 can be prevented without using complicated control.

  In the fourth embodiment, instead of the orifice 442, a mechanical control valve that opens when the pressure of the humidified water supply pipe 402a falls below a predetermined pressure may be provided.

It is a figure which shows schematic structure of the internal drying prevention apparatus of the fuel cell by 1st Embodiment. It is a figure which shows schematic structure of the internal dry prevention apparatus of the fuel cell by 2nd Embodiment. It is a figure which shows schematic structure of the internal drying prevention apparatus of the fuel cell by 3rd Embodiment. It is a figure which shows schematic structure of the internal dry prevention apparatus of the fuel cell by 4th Embodiment.

Explanation of symbols

16 Hydrogen channel (fuel gas channel)
17 Anode separator (porous separator)
18 Air channel (oxidant gas channel)
18a Air channel inlet (oxidant gas channel inlet)
19 Humidification water channel (water channel)
19a Humidification water channel inlet (water channel inlet)
20 Cathode separator (porous separator)
201 Compressor 202 Air supply piping (oxidant gas piping)
401 Water tank (humidified water tank)
402 Humidification water supply piping (water piping)
403 Humidification water control valve (Water supply amount adjusting means)
404 Drainage pipe 405 Sub tank 406 Water distribution recovery pipe (water recovery pipe)
407 Wastewater recovery air supply piping (oxidant gas bypass piping)
408 Drainage control valve
409 Air control valve for wastewater recovery (switching valve)
421 Pressure sensor 431 Pump 441 Bypass passage (water supply amount adjusting means)
442 Orifice (water supply amount adjusting means)

Claims (10)

An internal drying prevention device for a fuel cell that prevents drying of the inside of the fuel cell in which the water channel and the oxidant gas channel or the fuel gas channel are arranged via a porous separator,
A water tank for storing water to be supplied to the water flow path;
A water pipe connecting the water tank and the water flow path;
Water supply means for supplying water from the water tank to the water flow path via the water pipe;
Water holding means for holding the water supplied to the water channel in the water channel;
A water supply amount adjusting means provided in the water pipe for adjusting the amount of water supplied by the water supply means while the fuel cell is stopped;
A device for preventing internal drying of a fuel cell. 2. The fuel cell internal drying prevention according to claim 1, wherein the water holding means is a valve provided in a drain pipe from which drainage from the fuel cell is discharged, and is closed when the fuel cell is stopped. apparatus. 2. The fuel cell internal drying prevention apparatus according to claim 1, wherein the water holding means is a dead end portion formed in the water flow path. The fuel cell according to any one of claims 1 to 3, wherein the water supply amount adjusting means is a mechanical valve that opens when the pressure in the water flow path becomes a predetermined pressure or less. Internal dry prevention device. A pressure sensor in the water pipe;
The water supply amount adjusting means is an electromagnetic valve provided upstream of the pressure sensor and opened when the pressure detected by the pressure sensor becomes a predetermined pressure or less. The internal dry prevention device for a fuel cell according to any one of 3 to 3. 4. The internal dry prevention device for a fuel cell according to claim 1, wherein the water supply amount adjusting means is an electromagnetic valve that is opened every predetermined time. The water supply amount adjusting means is provided in the water pipe and opens when the compressor for introducing the oxidant gas into the oxidant gas flow path is operated, and is closed when the compressor is stopped to adjust the water supply amount by the water supply means. 4. The device according to claim 1, comprising a logic valve, a bypass passage provided in the water pipe and bypassing the logic valve, and an orifice provided in the bypass passage. An internal drying prevention device for a fuel cell according to claim 1. 8. The water tank according to claim 1, wherein the water supply means is a water tank that is disposed at a position higher than the fuel cell and supplies water to the water flow path by a head pressure of stored water. The internal dry prevention apparatus of the fuel cell as described in one. 8. The fuel cell internal drying prevention according to claim 1, wherein the water supply means is a pump provided in the water pipe upstream of the water supply amount adjustment means. apparatus. Drainage pipe from which drainage from the fuel cell is discharged;
A subtank connected to the drainage pipe and storing the drainage;
A water recovery pipe connecting the sub tank and the water tank in order to recover the waste water of the sub tank to the water tank;
A compressor for introducing an oxidant gas into the oxidant gas flow path;
An oxidant gas pipe connecting the oxidant gas flow path inlet and the compressor;
An oxidant gas bypass pipe for bypassing the fuel cell and connecting the oxidant gas pipe and the sub tank;
A switching valve for switching whether the oxidant gas is introduced into the oxidant gas flow path or the sub tank;
The internal dry prevention device for a fuel cell according to any one of claims 1 to 9, characterized by comprising: