JP5848375B2 - Fuel gas supply device - Google Patents

Description

  The present invention relates to a fuel gas supply device that supplies fuel gas to a diesel engine mounted on a ship.

2. Description of the Related Art Conventional marine vessels use a two-stroke cycle low-speed diesel engine that can output at low speed and can be driven directly by a propeller.
In recent years, natural gas with low CO ₂ emission has attracted attention as a fuel for low-speed diesel engines. By injecting and burning high-pressure natural gas (fuel gas) into the combustion chamber of a low-speed diesel engine, high output can be obtained with high thermal efficiency.

  In order to inject natural gas at a high pressure and inject it into the combustion chamber of a low-speed diesel engine, it is conceivable to increase the pressure of liquefied natural gas (hereinafter referred to as “LNG”) and then heat and vaporize it. Specifically, the LNG stored in the tank is boosted by a liquid pump, and the boosted LNG is heated by a vaporizer and vaporized before being injected into a combustion chamber of a low-speed diesel engine (for example, Patent Document 1) . In the gas fuel supply device described in Patent Document 1, a hydraulic pump arranged in a non-hazardous area is driven by an electric motor, and hydraulic pressure is supplied to a hydraulic motor arranged in the dangerous area by the hydraulic pump, and the above-described liquid is supplied by the hydraulic motor. The pump is being driven.

JP 2012-177333 A

  In the conventional method, in order to control the rotation speed of the hydraulic pump, the discharge amount of the hydraulic pump is adjusted. The discharge amount of the hydraulic pump is adjusted by adjusting the stroke of the piston by changing the angle of the swash plate attached to the output shaft of the hydraulic pump. However, with this method, even if the amount of hydraulic oil discharged from the hydraulic pump is changed, the hydraulic pump operates at the rated speed, so the oil temperature rises due to the frictional resistance inside the hydraulic pump. End up. When the temperature of the hydraulic oil rises, the temperature of the hydraulic motor rises, and the temperature of the liquid pump driven by the hydraulic motor rises. As a result, when the temperature of the liquid fuel rises in the liquid pump, cavitation is likely to occur in the liquid pump, and the pressure increase efficiency by the liquid pump decreases. In addition, there is a problem that maintenance such as flushing of hydraulic pipes and measures against oil leakage are complicated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel gas supply device that can increase the pressure increase efficiency of liquid fuel by a liquid pump and can be easily maintained. It is.

In order to solve the above problems, a first aspect of the present invention is a gas fuel supply device for supplying fuel gas into a combustion chamber of a diesel engine of a ship,
A liquid fuel tank for storing liquid fuel obtained by liquefying fuel gas;
A liquid pump for boosting the liquid fuel supplied from the liquid fuel tank;
A vaporizer that vaporizes liquid fuel supplied by the liquid pump and supplies the vaporized fuel to the combustion chamber;
A hydraulic motor for driving the liquid pump;
A hydraulic pump for driving the hydraulic motor;
A sealed supply pipe that directly connects the hydraulic motor and the hydraulic pump, and supplies all hydraulic oil discharged from the hydraulic pump to the hydraulic motor;
A sealed discharge pipe that directly connects the hydraulic motor and the hydraulic pump and returns all hydraulic fluid discharged from the hydraulic motor to the hydraulic pump;
An electric motor for driving the hydraulic pump;
A control unit for controlling the rotational speed of the hydraulic pump by performing shift control of the electric motor;
Is provided.

A second aspect of the present invention is a fuel gas supply device for supplying fuel gas into a combustion chamber of a marine diesel engine,
A liquid fuel tank for storing liquid fuel obtained by liquefying fuel gas;
A liquid pump for boosting the liquid fuel supplied from the liquid fuel tank;
A vaporizer that vaporizes liquid fuel supplied by the liquid pump and supplies the vaporized fuel to the combustion chamber;
A hydraulic motor for driving the liquid pump;
A plurality of hydraulic pumps for driving the hydraulic motor;
A sealed supply pipe that directly connects the hydraulic motor and the plurality of hydraulic pumps, and supplies all hydraulic oil discharged from the plurality of hydraulic pumps to the hydraulic motor;
A sealed discharge pipe that directly connects the hydraulic motor and the plurality of hydraulic pumps, and returns all the hydraulic oil discharged from the hydraulic motor to the plurality of hydraulic pumps;
A plurality of electric motors for driving the plurality of hydraulic pumps;
A control unit for controlling the plurality of electric motors;
With
The controller is configured to control the number of rotations of at least one hydraulic pump by controlling the speed of rotation of at least one electric motor to control the output of the hydraulic motor.

  It is preferable that the hydraulic pump is provided with a variable capacity hydraulic oil tank that stores the hydraulic oil in a sealed state.

The supply pipe is provided with a pressure gauge for measuring the pressure of the internal hydraulic oil,
It is preferable that the control unit controls the number of revolutions of the electric motor according to a measurement result of the pressure gauge.

A tachometer for measuring the rotation speed of the hydraulic motor;
It is preferable that the control unit controls the number of rotations of the electric motor according to a measurement result of the tachometer.

  The control unit and the electric motor are connected by wiring, the electric motor is disposed in a dangerous area, and the control unit is disposed in a non-hazardous area at least 8 meters away from the electric motor. preferable.

  It is preferable that the connection part of the said electric motor and the said wiring is an intrinsically safe explosion-proof structure.

  According to the present invention, since the rotation speed of the hydraulic pump is controlled by controlling the speed of the electric motor, the temperature of the hydraulic fluid in the hydraulic device is not increased, and the boosting efficiency of the liquid fuel by the liquid pump is increased. Can do. In addition, since the hydraulic supply pipe and the discharge pipe are sealed, a gas fuel supply apparatus that is easy to maintain without risk of oil leakage can be provided.

1 is a block diagram of a fuel gas supply device 10 according to a first embodiment of the present invention. It is the schematic of the pressure | voltage rise pump drive device 20A which concerns on 1st Embodiment. It is the schematic of the pressure | voltage rise pump drive device 20B which concerns on 2nd Embodiment. It is the schematic of the pressure | voltage rise pump drive device 20C which concerns on 3rd Embodiment. It is the schematic of booster pump drive device 20D concerning a 4th embodiment.

[First Embodiment]
Hereinafter, a fuel gas supply apparatus according to a first embodiment of the present invention will be described with reference to FIGS.
The fuel gas supply device 10 of the present embodiment is a device that injects and supplies fuel gas, which is a vaporized liquid fuel, into the combustion chamber of the diesel engine 90 at a high pressure. The diesel engine 90 of this embodiment is a diesel engine mounted on a ship, and for example, a two-stroke cycle low-speed diesel engine can be used.

As shown in FIG. 1, the fuel gas supply device 10 includes a liquid fuel tank 11, a booster pump 12, a vaporizer 14, a liquid fuel supply pipe 15, a boosted fuel supply pipe 16, and a fuel gas supply pipe 17. , A pressure regulating valve 18, a pressure gauge 19, a booster pump drive device 20 </ b> A, and a control unit 60.
All these components of the fuel gas supply device 10 are mounted on a ship. The liquid fuel tank 11, the booster pump 12, the carburetor 14, the liquid fuel supply pipe 15, the booster fuel supply pipe 16, the fuel gas supply pipe 17, the pressure regulating valve 18, the pressure gauge 19, and the booster pump drive device 20A are in the hazardous area HA. The control unit 60 is disposed in the non-hazardous area NHA. The dangerous area HA is preferably a section separated from the non-hazardous area NHA by a partition wall (A60 class partition) (not shown).

  Here, “dangerous area” means an area where there is or may be an amount of gaseous explosive atmosphere that requires special precautions for the assembly, installation and use of equipment. . “Non-hazardous area” refers to an area where it can be predicted that there will be no gaseous explosive atmosphere in an amount that requires special precautions for assembly, installation and use of the equipment. “Class A partition” means (i) a material equivalent to copper or steel, (ii) appropriately reinforced, and (iii) heat-resistant with a nonflammable material And (iv) a partition formed by partitions or decks that can block the passage of smoke and flame until the 60 minute standard fire test is over. “A60 class partition” means the heat insulation time in the standard fire test (the average temperature on the non-flammable side does not rise above 140 degrees Celsius from the initial temperature, and the initial temperature at any point including the joint) Refers to the time during which the temperature does not rise beyond 180 degrees Celsius).

  The liquid fuel tank 11 stores liquid fuel before the fuel gas supplied to the diesel engine 90 is vaporized. As the liquid fuel, liquefied natural gas (LNG), liquefied petroleum gas (LPG), or the like can be used. The liquid fuel tank 11 is connected to the liquid fuel supply pipe 15 and supplies the liquid fuel to the booster pump 12 through the liquid fuel supply pipe 15.

  The booster pump 12 has an inlet side connected to the liquid fuel supply pipe 15 and an outlet side connected to the boosted fuel supply pipe 16. The booster pump 12 boosts the liquid fuel supplied from the liquid fuel supply pipe 15 and supplies it to the carburetor 14 via the boosted fuel supply pipe 16. As the booster pump 12, a reciprocating pump of a type in which a movable part (plunger or the like) reciprocates can be used. The booster pump 12 is driven by a booster pump drive device 20A described later. The rotational speed of the diesel engine 90 is adjusted by the amount of liquid fuel supplied by the booster pump.

  The vaporizer 14 has an inlet side connected to the boosted fuel supply pipe 16 and an outlet side connected to the fuel gas supply pipe 17. The vaporizer 14 heats and vaporizes the pressurized liquid fuel supplied through the pressurized fuel supply pipe 16. As a heat source for heating the liquid fuel, for example, combustion heat of boil-off gas generated in the liquid fuel tank 11 can be used. For example, the liquid fuel may be heated by heat exchange with warm water heated by the combustion heat of boil-off gas.

The fuel gas supply pipe 17 is provided with a pressure regulating valve 18, one end of which is connected to the carburetor 14 and the other end is connected to the combustion chamber of the diesel engine 90. The fuel gas in which the liquid fuel is vaporized is regulated to a pressure within a predetermined range (for example, 150 to 300 bar) by the pressure regulating valve 18 and then supplied to the combustion chamber of the diesel engine 90 via the fuel gas supply pipe 17. .
The fuel gas supply pipe 17 is provided with a pressure gauge 19. The pressure gauge 19 measures the pressure in the fuel gas supply pipe 17 and outputs a measurement signal to the control unit 60.

The control unit 60 controls a booster pump drive device 20A, which will be described later, in accordance with the measurement signal output from the pressure gauge 19. Further, the control unit 60 controls the booster pump drive device 20A according to the rotational speed of the diesel engine 90 required according to the speed of the ship on which the fuel gas supply device 10 is mounted.
For example, when the boat speed is low and the load is low in a harbor or the like, the rotational speed of the diesel engine 90 is decreased (for example, 60 rpm). At this time, the boost pump driving device 20A is feedback-controlled so that the pressure measured by the pressure gauge 19 is relatively low (for example, 250 bar).
On the other hand, for example, when the boat speed is fast and the load is high in the open ocean, the rotational speed of the diesel engine 90 is increased (for example, 120 rpm). At this time, the boost pump driving device 20A is feedback-controlled so that the pressure measured by the pressure gauge 19 becomes relatively high (for example, 300 bar).
Even in cases other than the above, in order to adjust the rotational speed of the diesel engine 90 according to the load, the booster pump drive device 20A is set so that the pressure measured by the pressure gauge 19 becomes a pressure corresponding to the desired rotational speed. Feedback control.

Next, the booster pump drive device 20A will be described. FIG. 2 is a schematic diagram of the booster pump drive device 20A. The booster pump drive device 20A includes a hydraulic motor 21, a supply pipe 22, a discharge pipe 23, a hydraulic pump 24, an electric motor 25, and an electric motor control unit 29.
The hydraulic motor 21 is a power source that drives the booster pump 12. For example, the rotational movement of the hydraulic motor 21 can be converted into the reciprocating movement of the cylinder of the plunger pump using a crank (not shown).
The supply pipe 22 directly connects the hydraulic motor 21 and the hydraulic pump 24, and supplies all the hydraulic oil discharged from the hydraulic pump 24 to the hydraulic motor 21.
The discharge pipe 23 directly connects the hydraulic motor 21 and the hydraulic pump 24 and returns all the hydraulic oil discharged from the hydraulic motor 21 to the hydraulic pump 24.
The hydraulic pump 24 is a power source that drives the hydraulic motor 21 and is driven by an electric motor 25. As the hydraulic pump 24, for example, a fixed displacement pump such as a gear pump is preferably used. By using a fixed displacement pump as the hydraulic pump 24, the amount of hydraulic oil discharged can be adjusted by changing the rotation speed of the hydraulic pump 24, and the temperature rise of the hydraulic oil due to frictional resistance can be reduced.

The electric motor 25 is controlled by the electric motor control unit 29. The electric motor 25 is connected to the electric motor control unit 29 by wiring 30. The electric motor 25 is preferably disposed in the hazardous area HA, and the electric motor control unit 29 is preferably disposed in the non-hazardous area NHA at least 8 meters away from the electric motor 25. Since the electric motor 25 is disposed in a hazardous area, it is preferably a safety device. Moreover, it is preferable that the connection part of the electric motor 25 and the wiring 30 is an intrinsically safe explosion-proof structure. By using the electric motor 25, which is a safety device, and the connection portion between the electric motor 25 and the wiring 30 has an intrinsically safe explosion-proof structure, the electric motor 25 can be arranged in the zero risk area.
Here, the “real safety device” refers to an electrical device that is a circuit in which a spark or heat generated does not ignite a target explosive gas atmosphere when a circuit inside the device is in a normal state and a specific failure state. The “intrinsically safe explosion-proof structure” means an explosion-proof system that suppresses the electrical energy of the interconnection wiring exposed to the inside of the container and the explosive atmosphere to a level that causes ignition due to a spark or a temperature rise. The “hazardous zone 0” refers to a zone where an explosive atmosphere composed of a mixture of a gas, vapor or mist combustible substance and air continuously exists for a long time or frequently.

The hydraulic motor 21, the hydraulic pump 24, the supply pipe 22 and the discharge pipe 23 seal the internal hydraulic oil and block it from the outside air. Since the supply pipe 22 and the discharge pipe 23 are sealed, there is no risk of oil leakage, and maintenance can be performed easily.
The hydraulic pump 24 may be provided with a variable capacity hydraulic oil tank 26 that stores hydraulic oil in a sealed state. For example, by providing a bladder (an elastic film such as rubber in which gas is sealed) whose volume increases or decreases in accordance with the increase or decrease of the hydraulic oil inside the hydraulic oil tank 26, the hydraulic oil tank is sealed in the internal hydraulic oil. The capacity of 26 can be made variable. By providing such a hydraulic oil tank 26, even when the volume of the hydraulic oil increases or decreases due to a temperature change, for example, the volume of the hydraulic oil tank 26 changes following the volume change of the hydraulic oil. The state where the hydraulic oil is sealed by the hydraulic pump 24, the supply pipe 22, and the discharge pipe 23 can be maintained.

  Further, a pressure gauge 27 that measures the pressure of the hydraulic oil inside the supply pipe 22 may be provided, and the control unit 60 may control the rotation speed of the electric motor 25 according to the measurement result of the pressure gauge 27. Thereby, the pressure of the hydraulic oil in the supply pipe 22 can be kept within a certain range.

  Further, a tachometer 28 for measuring the rotation speed of the hydraulic motor 21 may be provided, and the control unit 60 may control the rotation speed of the electric motor 25 according to the measurement result of the tachometer 28. Thereby, the rotation speed of the hydraulic motor 21 can be kept at a desired value.

  Here, the desired number of rotations of the hydraulic motor 21 varies depending on the pressure of fuel gas (pressure measured by the pressure gauge 19) necessary for supplying the oil into the combustion chamber of the diesel engine 90. For example, when the ship speed is low and the load is low in a harbor or the like, the rotational speed of the diesel engine 90 is small (for example, 60 rpm), and the pressure measured by the pressure gauge 19 may be relatively low (for example, 250 bar). Therefore, the desired number of rotations of the hydraulic motor 21 is reduced. On the other hand, for example, when the ship speed is high and the load is high in the open ocean or the like, the rotational speed of the diesel engine 90 needs to be large (for example, 120 rpm), and the pressure measured by the pressure gauge 19 is relatively high (for example, 300 bar). Therefore, the desired number of rotations of the hydraulic motor 21 increases. In any case, the control unit 60 is electrically operated so that the rotational speed of the hydraulic motor 21 is maintained at a desired value so that the rotational speed of the diesel engine 90 and the pressure measured by the pressure gauge 19 become a desired value. The motor 25 is controlled.

According to the present embodiment, the electric motor 25 controls the rotational speed of the hydraulic pump 24 and controls the output of the hydraulic motor 21, so that the power consumption of the electric motor 25 during low speed navigation (low output) such as in a harbor. Can be reduced. For this reason, the temperature of the hydraulic oil does not increase, and the temperature of the hydraulic motor 21 and the temperature of the booster pump 12 do not increase as in the case of performing output control using a swash plate. Therefore, the temperature of the liquid fuel in the booster pump 12 does not rise, the occurrence of cavitation in the booster pump 12 can be suppressed, and the boosting efficiency of the liquid pump can be increased.
In the present embodiment, since the hydraulic motor 21 and the hydraulic pump 24 are provided in the hazardous area HA, the supply pipe 22 and the discharge pipe 23 can be shortened. For this reason, maintenance such as flushing of the supply pipe 22 and the discharge pipe 23 and measures against oil leakage can be simplified.

[Second Embodiment]
FIG. 3 is a schematic diagram of a booster pump drive device 20B according to the second embodiment of the present invention. In addition, about the structure similar to the pressure | voltage rise pump drive device 20A of 1st Embodiment, the same code | symbol is attached | subjected and description is omitted.
In the present embodiment, in addition to the electric motor control unit 29 among the hydraulic motor 21, the supply pipe 22, the discharge pipe 23, the hydraulic pump 24, the electric motor 25, and the electric motor control unit 29 constituting the booster pump drive device 20B. The point from which the hydraulic pump 24 and the electric motor 25 are further arrange | positioned in non-hazardous area NHA differs from the said embodiment.

  Also in the present embodiment, as in the first embodiment, the temperature rise of the liquid fuel in the booster pump 12 can be suppressed, the occurrence of cavitation in the booster pump 12 can be suppressed, and the efficiency of the boosting by the liquid pump can be suppressed. Can be increased.

  Also in this embodiment, the hydraulic pump 24 may be provided with a variable capacity hydraulic oil tank 26 that stores hydraulic oil in a sealed state. Further, a pressure gauge 27 that measures the pressure of the hydraulic oil inside the supply pipe 22 may be provided, and the control unit 60 may control the rotation speed of the electric motor 25 according to the measurement result of the pressure gauge 27. Further, a tachometer 28 for measuring the rotation speed of the hydraulic motor 21 may be provided, and the control unit 60 may control the rotation speed of the electric motor 25 according to the measurement result of the tachometer 28.

[Third Embodiment]
FIG. 4 is a schematic view of a booster pump drive device 20C according to the third embodiment of the present invention. In addition, about the structure similar to the pressure | voltage rise pump drive device 20A of 1st Embodiment, the same code | symbol is attached | subjected and description is omitted.
In the present embodiment, there is one hydraulic motor 21, but the supply pipe 22 is branched into a plurality of supply pipes 22A and 22B, and the discharge pipe 23 is branched into a plurality of discharge pipes 23A and 23B. This is different from the first embodiment in that a plurality of hydraulic pumps 24A and 24B and a plurality of electric motors 25A and 25B are provided.

In the present embodiment, the electric motor control unit 29 controls the speed of at least one of the hydraulic pumps 24A and 24B by performing speed change control on at least one of the plurality of electric motors 25A and 25B. Output can be controlled. The plurality of hydraulic pumps 24A and 24B are provided in parallel, the supply pipe 22A and the discharge pipe 23A are provided in the hydraulic pump 24A, and the supply pipe 22B and the discharge pipe 23B are provided in the hydraulic pump 24B. Even in this case, the hydraulic motor 21 can be driven using the hydraulic pump 24B.
Further, similarly to the first embodiment, the temperature rise of the liquid fuel in the booster pump 12 can be suppressed, the occurrence of cavitation in the booster pump 12 can be suppressed, and the boosting efficiency by the liquid pump can be increased. it can.

  Also in this embodiment, the hydraulic pumps 24A and 24B may be provided with variable capacity hydraulic oil tanks 26A and 26B that store hydraulic oil in a sealed state. In addition, a pressure gauge 27 that measures the pressure of the hydraulic oil inside the supply pipe 22 is provided, and the control unit 60 controls the rotational speed of at least one of the electric motors 25A and 25B according to the measurement result of the pressure gauge 27. Good. Further, a tachometer 28 for measuring the rotation speed of the hydraulic motor 21 may be provided, and the control unit 60 may control at least one rotation speed of the electric motors 25A and 25B according to the measurement result of the tachometer 28.

[Fourth Embodiment]
FIG. 5 is a schematic view of a booster pump drive device 20D according to the fourth embodiment of the present invention. In addition, about the structure similar to the pressure | voltage rise pump drive device 20C of 3rd Embodiment, the same code | symbol is attached | subjected and description is omitted.
In the present embodiment, among the hydraulic motor 21, the supply pipes 22A and 22B, the discharge pipes 23A and 23B, the hydraulic pumps 24A and 24B, the electric motors 25A and 25B, and the electric motor control unit 29 that constitute the booster pump drive device 20D. In addition to the electric motor control unit 29, the hydraulic pumps 24A and 24B and the electric motors 25A and 25B are further arranged in the non-hazardous area NHA, which is different from the above embodiment.

Also in the present embodiment, as in the third embodiment, the electric motor control unit 29 performs shift control of at least one rotation of the plurality of electric motors 25A and 25B, so that at least one rotation speed of the hydraulic pumps 24A and 24B. And the output of the hydraulic motor 21 can be controlled. In addition, since the plurality of hydraulic pumps 24A and 24B are provided in parallel, the supply pipe 22A and the discharge pipe 23A are provided in the hydraulic pump 24A, and the supply pipe 22B and the discharge pipe 23B are provided in the hydraulic pump 24B. Even in this case, the hydraulic motor 21 can be driven using the hydraulic pump 24B.
Furthermore, the temperature rise of the liquid fuel in the booster pump 12 can be suppressed, the occurrence of cavitation in the booster pump 12 can be suppressed, and the boosting efficiency by the liquid pump can be increased.

  Also in this embodiment, the hydraulic pumps 24A and 24B may be provided with variable capacity hydraulic oil tanks 26A and 26B that store hydraulic oil in a sealed state. In addition, a pressure gauge 27 that measures the pressure of the hydraulic oil inside the supply pipe 22 is provided, and the control unit 60 controls the rotational speed of at least one of the electric motors 25A and 25B according to the measurement result of the pressure gauge 27. Good. Further, a tachometer 28 for measuring the rotation speed of the hydraulic motor 21 may be provided, and the control unit 60 may control at least one rotation speed of the electric motors 25A and 25B according to the measurement result of the tachometer 28.

In the above description, the case where the liquid fuel is LNG has been described. However, the present invention is not limited to this, and liquid fuel such as LPG may be used. Further, in the present embodiment, the case where the liquid fuel is boosted in one stage by the single booster pump 12 has been described, but the liquid fuel may be boosted in multiple stages using a plurality of booster pumps.
Moreover, the rotation speed of the diesel engine 90 and the pressure of the fuel gas supplied to the diesel engine 90 in the above description are examples, and the present invention is not limited to this.

HA Hazardous Area NHA Non-hazardous Area 10 Fuel Gas Supply Device 11 Liquid Fuel Tank 12 Booster Pump 14 Vaporizer 15 Liquid Fuel Supply Pipe 16 Boosted Fuel Supply Pipe 17 Fuel Gas Supply Pipe 18 Pressure Regulator 19 Pressure Gauges 20A, 20B, 20C, 20D Booster pump drive device 21 Hydraulic motors 22, 22A, 22B Supply piping 23, 23A, 23B Discharge piping 24, 24A, 24B Hydraulic pumps 25, 25A, 25B Electric motor 26 Hydraulic oil tank 27 Pressure gauge 28 Tachometer 29 Electric motor controller 30 Wiring 60 Control unit 90 Diesel engine

Claims (7)

A fuel gas supply device for supplying fuel gas into a combustion chamber of a marine diesel engine,
A liquid fuel tank for storing liquid fuel obtained by liquefying fuel gas;
A liquid pump for boosting the liquid fuel supplied from the liquid fuel tank;
A vaporizer that vaporizes liquid fuel supplied by the liquid pump and supplies the vaporized fuel to the combustion chamber;
A hydraulic motor for driving the liquid pump;
A hydraulic pump for driving the hydraulic motor;
A sealed supply pipe that directly connects the hydraulic motor and the hydraulic pump, and supplies all hydraulic oil discharged from the hydraulic pump to the hydraulic motor;
A sealed discharge pipe that directly connects the hydraulic motor and the hydraulic pump and returns all hydraulic fluid discharged from the hydraulic motor to the hydraulic pump;
An electric motor for driving the hydraulic pump;
A control unit for controlling the rotational speed of the hydraulic pump by performing shift control of the electric motor;
Equipped with a,
Wherein said control unit and the electric motor are connected by wires, the electric motor is disposed in hazardous areas, the control unit Ru is disposed in a non-hazardous area away with the electric motor, the fuel gas supply system. A fuel gas supply device for supplying fuel gas into a combustion chamber of a marine diesel engine,
A liquid fuel tank for storing liquid fuel obtained by liquefying fuel gas;
A liquid pump for boosting the liquid fuel supplied from the liquid fuel tank;
A vaporizer that vaporizes liquid fuel supplied by the liquid pump and supplies the vaporized fuel to the combustion chamber;
A hydraulic motor for driving the liquid pump;
A plurality of hydraulic pumps for driving the hydraulic motor;
A sealed supply pipe that directly connects the hydraulic motor and the plurality of hydraulic pumps, and supplies all hydraulic oil discharged from the plurality of hydraulic pumps to the hydraulic motor;
A sealed discharge pipe that directly connects the hydraulic motor and the plurality of hydraulic pumps, and returns all the hydraulic oil discharged from the hydraulic motor to the plurality of hydraulic pumps;
A plurality of electric motors for driving the plurality of hydraulic pumps;
A control unit for controlling the plurality of electric motors;
With
The control unit and the electric motor are connected by wiring, the electric motor is disposed in a dangerous area, the control unit is disposed in a non-hazardous area apart from the electric motor,
The said control part is a fuel gas supply apparatus which controls the rotation speed of at least 1 hydraulic pump by carrying out transmission control of the rotation of at least 1 electric motor, and controls the output of the said hydraulic motor.   The fuel gas supply device according to claim 1 or 2, wherein the hydraulic pump is provided with a variable capacity hydraulic oil tank that stores the hydraulic oil in a sealed state. The supply pipe is provided with a pressure gauge for measuring the pressure of the internal hydraulic oil,
The fuel gas supply device according to any one of claims 1 to 3, wherein the control unit controls the number of revolutions of the electric motor according to a measurement result of the pressure gauge. A tachometer for measuring the rotation speed of the hydraulic motor;
The said control part is a fuel gas supply apparatus as described in any one of Claims 1-4 which controls the rotation speed of the said electric motor according to the measurement result of the said tachometer. The control unit is arranged at least 8 meters away from the electric motor ,
The fuel gas supply apparatus as described in any one of Claims 1-5.   The fuel gas supply device according to any one of claims 1 to 6, wherein a connection portion between the electric motor and the wiring has an intrinsically safe explosion-proof structure.

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