JP5194969B2 - Fluid dispensing device - Google Patents

Description

  The present invention relates to a fluid dispensing device.

As is well known, an LNG (liquefied natural gas) base vaporizes LNG stored in an LNG tank using a vaporizer, and provides the natural gas output from the vaporizer as a fuel to consumers such as thermal power plants It is a facility to do. Such an LNG base supplies LNG from the LNG tank to the carburetor using a dedicated discharge pump (LNG pump). However, a pipe (header) connecting the LNG pump and the carburetor is connected to the currently operating LNG base. In order to prevent the internal pressure of the piping) from abruptly fluctuating due to the start / stop of the LNG pump, an outlet flow rate adjusting valve is provided on the outlet side of the LNG pump, and for preventing the LNG pump from surging, Some are provided with a reflux pipe (miniflow pipe) through which a small amount of LNG passes between the LNG tank. This mini flow pipe is provided with a flow rate adjusting valve (mini flow rate adjusting valve) for adjusting the amount of reflux to the LNG tank.
For example, the following Patent Documents 1 and 2 disclose the technology related to paying out LNG from the LNG tank at the LNG base.
JP 10-318499 A JP 08-285194 A

  By the way, in the existing LNG base, since two control valves (an outlet flow rate control valve and a mini-flow flow rate control valve) are provided when the LNG is discharged from the LNG tank, the equipment cost relating to the control valve itself and its control system increases. At the same time, there is a problem that the amount of maintenance work increases. In order to provide two control valves, it is necessary to secure a corresponding installation space. However, in order to secure this installation space, there is a problem that the arrangement of each device in the LNG base is restricted.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to realize suppression of rapid pressure fluctuation of a header pipe and prevention of surging of an LNG pump by using one control valve.

In order to achieve the above object, according to the present invention, as a first solution, the fluid stored in the tank is discharged by a pump, supplied to a customer through a header pipe, and part of the fluid discharged by the pump is returned. A fluid discharge device that recirculates to a tank via a pipe, and includes a control valve provided in the recirculation pipe, a flow meter that detects the flow rate of the fluid that passes through the pump, and a control valve that is based on the detection value of the flow meter When the pump is started, the control valve is controlled using the first flow rate as a flow rate set value, and when the pump is instructed to stop, a second flow rate larger than the first flow rate is set as the flow rate set value. And a controller that controls the control valve using the first flow rate as a flow rate set value when the pump is stopped.
As a second solution, in the first means, when the controller is instructed to stop the pump, the controller gradually changes the flow rate set value from the first flow rate to the second flow rate at a predetermined rate of change. , Is adopted.
As a third solution, in the first or second means, when the pump is stopped, the controller gradually changes the flow rate setting value from the second flow rate to the first flow rate at a predetermined rate of change. Adopt the means.
As a fourth solution, in any one of the first to third means, the liquefied natural gas from the tank in the LNG base that vaporizes the liquefied natural gas (LNG) stored in the tank and outputs it to the outside. The method of paying out and supplying to the carburetor that is the demand destination is adopted.

According to the present invention, when the pump is started, the control valve is controlled using the first flow rate as the flow rate set value, so that the control valve is fully opened and the flow rate of the fluid flowing through the reflux pipe is gradually increased. Accordingly, the opening of the control valve gradually decreases and becomes fully closed, and the flow rate of the fluid supplied to the header pipe gradually increases. If the pump is instructed to stop after operating in such a state, the control valve is controlled using the second flow rate larger than the first flow rate as a flow rate set value. As the flow rate increases, the flow rate of the fluid flowing through the reflux pipe gradually increases, and with this increase, the flow rate of the fluid supplied to the header pipe gradually decreases to zero. When the pump is stopped, the control valve is controlled using the first flow rate as a flow rate set value, so that the control valve is fully opened and the flow rate of the fluid flowing through the return pipe is reduced. It becomes zero.
According to the present invention having such an action, when a flow rate of the fluid supplied to the header pipe is relatively small, the surging of the pump is caused by the flow of the fluid to the reflux pipe when the flow rate of the fluid supplied to the header pipe is relatively small. In addition, since the flow rate of the fluid in the header pipe changes gently, sudden pressure fluctuations in the header pipe can be suppressed.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram of an LNG payout apparatus according to the present embodiment. In this figure, reference numerals 1A, 1B are LNG tanks, 2A1, 2A2, 2B1, 2B2 are LNG pumps, 3A1, 3A2, 3B1, 3B2 are flow meters, 4A1, 4A2, 4B1, 4B2 are mini-flow pipes, 5A1, 5A2, 5B1, 5B2 are mini-flow flow rate control valves (control valves), 6A1, 6A2, 6B1, 6B2 are controllers, 7A1, 7A2, 7B1, 7B2 are header pipes, 8A, 8B are on-off valves, and 9 is a vaporizer.

  Among these plural components, LNG pumps 2A1, 2A2, flowmeters 3A1, 3A2, miniflow pipes 4A1, 4A2, miniflow flow control valves 5A1, 5A2, controllers 6A1, 6A2 and header pipes 7A1, 7A2 are LNG. LNG delivery device for tank 1A is configured, LNG pumps 2B1, 2B2, flowmeters 3B1, 3B2, miniflow piping 4B1, 4B2, miniflow flow control valves 5B1, 5B2, controllers 6B1, 6B2 and header piping 7B1, 7B2 , An LNG dispensing device relating to the LNG tank 1B is configured. The plurality of components constitute an LNG base that vaporizes LNG (liquefied natural gas) and outputs it to an external fuel demand facility (for example, a thermal power plant or a city gas supply facility).

  The LNG tank 1A is an above-ground or underground structure that stores LNG (liquefied natural gas), which is a kind of fluid, and has two LNG pumps 2A1 and 2A2 provided therein. The LNG tank 1B is an above-ground type or underground type structure that stores LNG (liquefied natural gas) in the same manner as the LNG tank 1A, and includes two LNG pumps 2B1 and 2B2. The LNG pump 2A1 is a dispensing pump that dispenses LNG from the LNG tank 1A and supplies it to the mini-flow pipe 4A1 and the header pipe 7A1. The LNG pump 2A2 is a dispensing pump that dispenses LNG from the LNG tank 1A and supplies it to the mini-flow pipe 4A2 and the header pipe 7A2. The LNG pump 2B1 is a dispensing pump that dispenses LNG from the LNG tank 1B and supplies it to the mini-flow pipe 4B1 and the header pipe 7B1. The LNG pump 2B2 is a dispensing pump that dispenses LNG from the LNG tank 1B and supplies it to the mini-flow pipe 4B2 and the header pipe 7B2.

  The flow meter 3A1 is provided on the outlet side (LNG discharge side) of the LNG pump 2A1, detects the flow rate of LNG passing through the LNG pump 2A1, and outputs a flow rate detection signal indicating the flow rate to the controller 6A1. . The flow meter 3A2 is provided on the outlet side (LNG discharge side) of the LNG pump 2A2, detects the flow rate of LNG passing through the LNG pump 2A2, and outputs a flow rate detection signal indicating the flow rate to the controller 6A2. . The flow meter 3B1 is provided on the outlet side (LNG discharge side) of the LNG pump 2B1, detects the flow rate of LNG passing through the LNG pump 2B1, and outputs a flow rate detection signal indicating the flow rate to the controller 6B1. . The flow meter 3B2 is provided on the outlet side (LNG discharge side) of the LNG pump 2B2, detects the flow rate of LNG passing through the LNG pump 2B2, and outputs a flow rate detection signal indicating the flow rate to the controller 6B2. .

  The mini-flow pipe 4A1 is laid between the outlet side of the LNG pump 2A1 and the LNG tank 1A, and the LNG pump 2A1 returns to return a part of the LNG discharged from the LNG tank 1A to the LNG tank 1A. It is piping. The mini-flow pipe 4A2 is laid between the outlet side of the LNG pump 2A2 and the LNG tank 1A, and the LNG pump 2A2 recirculates a part of the LNG discharged from the LNG tank 1A to the LNG tank 1A. It is piping. The mini-flow pipe 4B1 is laid between the outlet side of the LNG pump 2B1 and the LNG tank 1B, and the LNG pump 2B1 returns to return a part of the LNG discharged from the LNG tank 1B to the LNG tank 1B. It is piping. The mini-flow pipe 4B2 is laid between the outlet side of the LNG pump 2B2 and the LNG tank 1B, and the LNG pump 2B2 returns to return a part of the LNG discharged from the LNG tank 1B to the LNG tank 1B. It is piping.

  The mini-flow flow rate adjusting valve 5A1 is provided in the middle of the mini-flow pipe 4A1, and controls the flow rate of LNG passing through the mini-flow pipe 4A1 by being controlled by the controller 6A1. The mini-flow flow rate adjusting valve 5A2 is provided in the middle of the mini-flow pipe 4A2, and is controlled by the controller 6A2 to adjust the flow rate of LNG passing through the mini-flow pipe 4A2. The mini-flow flow rate adjusting valve 5B1 is provided at an intermediate portion of the mini-flow pipe 4B1, and is controlled by the controller 6B1 to adjust the flow rate of LNG passing through the mini-flow pipe 4B1. The mini-flow flow rate adjusting valve 5B2 is provided in the middle of the mini-flow pipe 4B2, and controls the flow rate of LNG passing through the mini-flow pipe 4B2 by being controlled by the controller 6B2.

  The controllers 6A1, 6A2, 6B1, and 6B2 are composed of an MPU (Micro Processing Unit), a memory, various interface circuits, and the like, and a predetermined control program and flow meters 3A1, 3A2, 3B1, and 3B2 stored in the memory in advance. The MPU executes predetermined information processing based on the LNG flow rate input from the pump and pump control information (information indicating the control status of the LNG pumps 2A1, 2A2, 2B1, 2B2) input from the pump control system, which is the host control system As a result, the respective mini-flow flow rate control valves 5A1, 5A2, 5B1, and 5B2 are feedback-controlled.

The controller 6A1 feedback-controls the mini-flow flow rate adjusting valve 5A1 based on the flow rate detection signal input from the flow meter 3A1 and the pump control information input from the pump control system. The controller 6A2 feedback-controls the mini-flow flow rate adjusting valve 5A2 based on the flow rate detection signal input from the flow meter 3A2 and the pump control information input from the pump control system. The controller 6B1 feedback-controls the mini-flow flow rate adjustment valve 5B1 based on the flow rate detection signal input from the flow meter 3B1 and the pump control information input from the pump control system. The controller 6B2 feedback-controls the mini-flow flow rate adjusting valve 5B2 based on the flow rate detection signal input from the flow meter 3B2 and the pump control information input from the pump control system.
The control operation of each controller 6A1, 6A2, 6B1, 6B2 will be described in detail later.

  The header pipe 7A1 is laid between the outlet side of the LNG pump 2A1 and the carburetor 9, and supplies the LNG discharged from the LNG tank 1A by the LNG pump 2A1 to the carburetor 9 which is the demand destination of the LNG dispensing device. It is supply piping for. The header pipe 7A2 is laid between the outlet side of the LNG pump 2A2 and the carburetor 9, and supplies the LNG discharged from the LNG tank 1A by the LNG pump 2A2 to the carburetor 9 that is the demand destination of the LNG dispensing device. It is supply piping for. The header pipe 7B1 is laid between the outlet side of the LNG pump 2B1 and the carburetor 9, and supplies the LNG discharged from the LNG tank 1B by the LNG pump 2B1 to the carburetor 9 that is the demand destination of the LNG dispensing device. It is supply piping for. The header pipe 7B2 is laid between the outlet side of the LNG pump 2B2 and the carburetor 9, and supplies the LNG discharged from the LNG tank 1B by the LNG pump 2B2 to the carburetor 9 that is the demand destination of the LNG dispensing device. It is supply piping for.

  As shown in the figure, among the header pipes 7A1, 7A2, 7B1, and 7B2, the pair of header pipes 7A1 and 7A2 that supply the LNG discharged from the LNG tank 1A to the vaporizer 9 are joined together and the LNG tank 1B. The pair of header pipes 7B1 and 7B2 that supply the LNG discharged from the vaporizer 9 to the vaporizer 9 merges in the middle, and further merge to finally become one pipe, and the LNG discharged from the two LNG tanks 1A and 1B. Is supplied to the vaporizer 9.

  The on-off valve 8A is provided at a part where the pair of header pipes 7A1 and 7A2 are joined, and the on-off valve 8B is provided at a part where the pair of header pipes 7B1 and 7B2 are joined. These two on-off valves 8A and 8B are normally both open and enable supply of LNG from the two LNG tanks 1A and 1B to the vaporizer 9, but from either of the LNG tanks 1A and 1B When the supply of LNG to the carburetor 9 is stopped, the stop side is closed. The carburetor 9 is a customer of each of the above LNG dispensing devices, and vaporizes and outputs the cryogenic LNG supplied from each LNG dispensing device using, for example, seawater.

  Next, with reference to FIGS. 2 to 4 as to the operation of the LNG dispensing device configured as described above, particularly the control operation of the mini-flow flow rate adjusting valves 5A1, 5A2, 5B1, and 5B2, which are characteristic operations of the LNG dispensing device. Will be described in detail.

First, each LNG pump 2A1, 2A2, 2B1, 2B2 in this LNG dispensing device is a high-order control system of the controllers 6A1, 6A2, 6B1, 6B2 whose control targets are the miniflow flow rate control valves 5A1, 5A2, 5B1, 5B2. The start, operation and stop are controlled by the pump control system. On the other hand, each controller 6A1, 6A2, 6B1, 6B2 has the pump control information (information indicating the control state of the LNG pumps 2A1, 2A2, 2B1, 2B2) and the flowmeters 3A1, 6A2, 6B2 provided from the pump control system. Based on the flow rate detection signals input from 3A2, 3B1, and 3B2, the mini-flow flow rate control valves 5A1, 5A2, 5B1, and 5B2 are feedback-controlled.
Since the operations of the controllers 6A1, 6A2, 6B1, and 6B2 are basically the same, the characteristic operation of the LNG payout apparatus will be described below by taking the controller 6A1 as an example.

  FIG. 2 is a flowchart showing the control operation of the controller 6A1 in accordance with the control program. When a start command for the LNG pump 2A1 is input as one of the pump control information (step S1), the controller 6A1 converts the flow rate detection signal input from the flow meter 3A1 into a mass flow rate (kg / s). (Step S2). That is, the flow rate detection signal is a signal indicating the flow rate by, for example, a current value (A: ampere), and the controller 6A1 converts the flow rate detection signal into a mass flow rate (kg / s) corresponding to the current value. Thus, the LNG flow rate on the outlet side of the LNG pump 2A1 is recognized.

  Subsequently, the controller 6A1 performs a process of determining a flow rate set value that is a control target value of the mini-flow flow rate control valve 5A1 (step S3), and is calculated in the above step S2 with the flow rate set value determined in step S3. The difference from the measured mass flow rate (kg / s) is calculated as a flow rate error (step S4). Then, the controller 6A1 calculates the PID manipulated variable by performing PID calculation (proportional integral differential calculation) on the flow rate error (step S5). Then, the controller 6A1 determines whether the control mode of the LNG pump 2A1 is set to the automatic mode / manual mode based on the pump control information (step S6). Is output to the mini-flow flow rate adjusting valve 5A1 (step S7), while in the manual mode, the manual operation amount input from the pump control system is output to the mini-flow flow rate adjusting valve 5A1 as one of the pump control information ( Step S8).

  The controller 6A1 feedback-controls the mini-flow flow rate adjusting valve 5A1 by processing the flow rate detection signal and the pump control information based on the control program as described above, but the controller 6A1 sets the flow rate as follows. By determining the value, surging of the LNG pump 2A1 by adjusting the flow rate of the LNG returning from the outlet side of the LNG pump 2A1 to the LNG tank 1A via the mini-flow pipe 4A1 (the discharge pressure and the discharge flow fluctuate periodically) Thus, the occurrence of mechanical damage to the LNG pump 2A1 is prevented, and sudden pressure fluctuations in the header pipe 7A1 are suppressed.

FIG. 3 is a flowchart showing details of the flow rate setting value determination process.
The controller 6A1 sets the flow rate setting value to a standard value defined in advance as shown in “flow rate setting value” in FIG. 4 in a state where the start command of the LNG pump 2A1 is input (step S3a). Here, in the stop period of the LNG pump 2A1 shown in FIG. 4, the LNG flow rate on the outlet side of the LNG pump 2A1 is “zero”.

  When the LNG pump 2A1 is started based on the start command, the LNG flow rate gradually increases, but the controller 6A1 sets the opening of the mini-flow flow rate control valve 5A1 as shown in “valve opening” of FIG. Since the LNG pump 2A1 is set to the fully open state, most of the LNG discharged from the LNG pump 2A1 flows into the miniflow pipe 4A1 having a lower pressure than the header pipe 7A1 as shown in “Miniflow flow rate” and “Header flow rate” in FIG. Reflux to the LNG tank 1A. That is, in a state where the discharge flow rate of the LNG pump 2A1 is relatively small, that is, in a state where the LNG pump 2A1 is prone to surging, the LNG flows into the miniflow pipe 4A1 to prevent the LNG pump 2A1 from surging.

  Further, since the flow rate error gradually decreases as the discharge flow rate gradually increases after the LNG pump 2A1 is started, the controller 6A1 has a mini-flow flow rate control valve as shown in “valve opening” in FIG. The opening of 5A1 is gradually decreased from the fully open state, and when the flow rate error finally becomes "zero", the fully closed state is set. Therefore, as shown in “Mini Flow Flow Rate” and “Header Flow Rate” in FIG. 4, among the LNG discharged from the LNG pump 2A1, the LNG flowing through the mini flow pipe 4A1 gradually decreases and finally becomes “zero”. On the other hand, the LNG flowing through the header pipe 7A1 gradually increases and fluctuates around the standard value.

That is, when the LNG pump 2A1 is activated, the LNG flowing through the header pipe 7A1 gradually increases, so that sudden pressure fluctuations in the header pipe 7A1 are suppressed.
The fully closed state of the mini-flow flow rate control valve 5A1 is a steady operation period of the LNG pump 2A1 shown in FIG. 4, and the supply amount of LNG in the header pipe 7A1 is a required amount of the carburetor.

  In such a steady operation state, when a stop command for the LNG pump 2A1 is input as pump control information (step S3b), the controller 6A1 sets the flow rate set value as shown in “flow rate set value” in FIG. The standard value is gradually increased from the standard value to the upper limit value at a constant rate of change (step S3c). As the flow rate set value increases, the flow rate error increases. Therefore, the controller 6A1 gradually increases the opening of the miniflow flow rate control valve 5A1 from the fully closed state. As shown in the “flow rate”, the LNG flowing through the mini-flow pipe 4A1 gradually increases.

  On the other hand, the discharge amount of the LNG pump 2A1 gradually decreases based on the stop command and finally enters a complete stop state. The period from the stop command to the complete stop of the LNG pump 2A1 is a stop preparation period shown in FIG. In this stop preparation period, as shown in “Mini Flow Flow Rate” and “Header Flow Rate” in FIG. 4, the LNG flowing through the header pipe 7A1 gradually decreases and finally becomes “zero”, but the mini flow pipe 4A1. The LNG flowing through the flow increases gradually. That is, the stop preparation period in which the discharge flow rate of the LNG pump 2A1 is gradually reduced is a state in which the LNG pump 2A1 is prone to surging, but since the LNG flows in the mini-flow pipe 4A1 instead of the header pipe 7A1, this stop preparation period However, surging of the LNG pump 2A1 is prevented and sudden pressure fluctuations in the header pipe 7A1 are suppressed.

  Further, when the stop (complete stop) of the LNG pump 2A1 is input as pump control information (step S3d), the controller 6A1 changes the flow rate set value to a constant value as shown in “flow rate set value” in FIG. The rate is gradually decreased from the upper limit value to the standard value (step S3e). As the flow rate setting value decreases, the flow rate error increases. Therefore, the controller 6A1 further increases the opening of the miniflow flow rate control valve 5A1 to make it fully open, but the LNG pump 2A1 has stopped. As a result, the flow rate of LNG flowing through the mini-flow pipe 4A1 becomes zero.

  According to this embodiment, the LNG pump is controlled by controlling the opening degree of the mini-flow flow rate control valves 5A1, 5A2, 5B1, 5B2 provided for each mini-flow pipe 4A1, 4A2, 4B1, 4B2. It is possible to prevent surging when starting and stopping 2A1, 2A2, 2B1, and 2B2, and to suppress rapid pressure fluctuations in the header pipes 7A1, 7A2, 7B1, and 7B2.

  For example, among the four LNG pumps 2A1, 2A2, 2B1, and 2B2, even if the LNG pump 2A1 stops, rapid pressure fluctuations in the header pipe 7A1 are suppressed, so that the other header pipes 7A2, 7B1, and 7B2 are routed. The LNG supply to the carburetor 9 is less disturbed, and therefore the LNG can be stably supplied to the carburetor 9 through the other header pipes 7A2, 7B1, and 7B2.

In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the above embodiment, when the stop command for the LNG pump 2A1 is determined, the flow rate set value is gradually increased from the standard value to the upper limit value at a constant rate of change, but the rate of change of the flow rate set value is not necessarily There is no need to set it gently. For example, if the “control delay element” in the feedback control system of the mini-flow flow rate control valves 5A1, 5A2, 5B1, 5B2 is relatively large, the header pipes 7A1, 7A2, Since the flow rate of LNG flowing through 7B1 and 7B2 does not change abruptly, the rate of change of the flow rate setting value may be made steep to some extent in consideration of the “control delay factor”.

(2) In the above embodiment, when the stop (complete stop) of the LNG pump 2A1 is determined, the flow rate set value is gradually decreased from the upper limit value to the standard value at a constant rate of change. The rate does not necessarily need to be set gently. For example, if the “control delay element” in the feedback control system of the mini-flow flow rate control valves 5A1, 5A2, 5B1, 5B2 is relatively large, the header pipes 7A1, 7A2, Since the flow rate of LNG flowing through 7B1 and 7B2 does not change abruptly, the rate of change of the flow rate setting value may be made steep to some extent in consideration of the “control delay factor”.

(3) In the above embodiment, when the stop command and stop (complete stop) of the LNG pump 2A1 are determined, the flow rate set value is changed to a constant change rate, that is, a ramp waveform shape. That is, it may be changed in a staircase shape.

(4) In the above embodiment, the LNG discharged from the two LNG tanks 1A and 1B is supplied to the carburetor 9 through four header pipes 7A1, 7A2, 7B1, and 7B2 that are finally unified. Although the case has been described, the present invention is not limited to this. LNG may be discharged from a single LNG tank and supplied to the vaporizer. That is, a configuration may be adopted in which one of the two LNG tanks 1A and 1B is deleted and the deleted LNG dispensing device is deleted.

(5) In the above embodiment, the two LNG tanks 1A, 1B each have two LNG pumps 2A1, 2A2, 2B1, 2B2, two flow meters 3A1, 3A2, 3B1, 3B2, and two mini-flow pipes 4A1, 4A2. , 4B1, 4B2, two mini-flow flow control valves 5A1, 5A2, 5B1, 5B2, two controllers 6A1, 6A2, 6B1, 6B2 and two header pipes 7A1, 7A2, 7B1, 7B2. Each LNG tank may be configured to include one LNG pump, a flow meter, a mini-flow pipe, a mini-flow flow control valve, a controller, and a header pipe.

1 is a system configuration diagram of an LNG payout apparatus according to an embodiment of the present invention. It is a flowchart which shows the control operation | movement of the LNG payout apparatus concerning one Embodiment of this invention. It is a flowchart which shows the flow volume setting process of the LNG dispensing apparatus concerning one Embodiment of this invention. It is a characteristic view which shows the operation | movement change of the LNG payout apparatus concerning one Embodiment of this invention.

Explanation of symbols

  1A, 1B ... LNG tank, 2A1, 2A2, 2B1, 2B2 ... LNG pump, 3A1, 3A2, 3B1, 3B2 ... Flowmeter, 4A1, 4A2, 4B1, 4B2 ... Mini-flow piping (reflux piping), 5A1, 5A2, 5B1 , 5B2 ... Mini-flow flow control valve (control valve), 6A1, 6A2, 6B1, 6B2 ... Controller, 7A1, 7A2, 7B1, 7B2 ... Header piping, 8A, 8B ... Open / close valve, 9 ... Vaporizer

Claims (4)

A fluid discharge device that discharges a fluid stored in a tank to a customer through a header pipe and supplies a part of the fluid discharged by the pump to the tank through a return pipe,
A control valve provided in the reflux pipe;
A flow meter for detecting the flow rate of the fluid passing through the pump;
The control valve is feedback-controlled based on a detection value of the flow meter. When the pump is started, the control valve is controlled using a first flow rate as a flow rate set value, and the stop of the pump is instructed. The control valve is controlled with a second flow rate larger than the first flow rate as a flow rate set value during the pump stop preparation period, and when the pump is stopped, the control is performed with the first flow rate as a flow rate set value. And a controller for controlling the valve.   2. The fluid according to claim 1, wherein when the pump is instructed to stop, the controller gradually changes the flow rate set value from the first flow rate to the second flow rate at a predetermined rate of change. Dispensing device.   3. The fluid dispensing device according to claim 1, wherein when the pump stops, the controller gradually changes the flow rate set value from the second flow rate to the first flow rate at a predetermined rate of change. . In an LNG base that vaporizes liquefied natural gas (LNG) as a fluid stored in the tank and outputs it to the outside, the liquefied natural gas is discharged from the tank and supplied to a vaporizer that is a demand destination. The fluid dispensing device according to any one of claims 1 to 3.

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