JP2009115195A - Liquefied gas filling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquefied gas filling device capable of safely filling liquefied gas without influence of a water hammer phenomenon. <P>SOLUTION: The liquefied gas is filled in a vehicle vessel 2 via a liquid line 6 from a storage vessel 3. A flow rate of the liquefied gas flowing in the liquid line 6 is always measured in a filling period by a flowmeter 9. Measured data is transmitted to a control part 5. A filling flow rate gradually reduces since pressure in the vehicle vessel 2 increase as filling advances. When a measured value of the flowmeter 9 reduces to a flow rate value or less just near when the filling to the vehicle vessel 2 finishes, the filling flow rate is reduced up to a flow rate value of not causing inconvenience in an apparatus in the filling device by the water hammer phenomenon on the vehicle vessel 2 side by control of a solenoid valve 12 for filling. When a filled flow rate is a value of not causing the inconvenience by the water hammer phenomenon, the flow rate is not adjusted by the solenoid valve 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquefied gas filling apparatus used when filling a filled container from a storage container with a liquefied gas such as liquefied DME (dimethyl ether), LPG (liquefied propane gas), LNG (liquefied natural gas), etc. The present invention relates to a liquefied gas filling device that prevents problems caused by an overfilling prevention valve that operates on the filled container side in order to prevent overfilling of liquefied gas.

  As fuel for automobiles and the like, liquefied gas such as liquefied petroleum gas and dimethyl ether has been used. For example, when filling an automobile using liquefied gas as fuel, generally (i) filling nozzle connection (ii) vehicle container side valve opening (iii) filling device switch on (filling start) (iv) inside vehicle container The overfilling prevention valve is closed (filling is stopped) (v) the filling device is switched off (vi) the vehicle container side valve is closed (vii) and the filling nozzle is removed. When filling, the pump is activated by discharging the switch to discharge the liquid, the float of the overfill prevention valve in the vehicle container rises, and the overfill prevention valve is turned on when a predetermined filling amount is reached. Close and stop filling.

  Patent Document 1 shown below describes an invention related to a filling valve for filling a pressure-resistant gas container with liquefied gas. As a filling valve for filling liquefied gas into the gas tank in the liquid state, in order to prevent the pressure in the gas tank from exceeding the specified value due to gas overfilling, the liquefied gas exceeding the preset storage amount is stored in the tank. There is disclosed a device equipped with an overfilling prevention valve that shuts off a gas flow path when the inside is filled.

No. 5-40399

  However, in the invention disclosed in Patent Document 1, the occurrence of the water hammer phenomenon due to the operation of the overfill prevention valve becomes a problem. For example, when filling a vehicle with liquefied gas such as liquefied petroleum gas as fuel, the overfill prevention valve on the vehicle container side when filling is completed closes rapidly when the specified amount is filled, so a large flow rate is required. In the case of filling, the impact of the water hammer may adversely affect each device in the filling apparatus and even the upstream pump. As a measure for preventing the water hammer, generally, an accumulator is added. However, the addition of the piping equipment has problems such as securing a space and generating a leak portion due to an increase in the number of connection points.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a liquefied gas filling apparatus that can safely fill liquefied gas without being affected by the water hammer phenomenon.

  In order to solve the above-mentioned problem, the invention of the liquefied gas filling device according to claim 1 is the liquefied gas filling device having a filling path for filling the filled liquid with the liquefied gas, and starts the filling of the liquefied gas. A filling start instructing means for instructing the flow rate, and a flow rate of the liquefied gas that is provided in the filling path and is filled in the container to be filled when the filling of the liquefied gas is started by operating the filling start instructing means A flow rate measuring means for measuring the flow rate, a flow rate adjusting valve provided in the filling path for adjusting the flow rate of the liquefied gas flowing through the filling path, and the pressure in the filled container that rises with the filling of the liquefied gas, And a flow rate control means for reducing the flow rate of the liquefied gas by adjusting the flow rate adjustment valve when the flow rate measured by the flow rate measurement means becomes equal to or less than a first predetermined flow rate value. It is characterized in.

  As the filling container is filled with the liquefied gas, the pressure in the filling container gradually increases. As the pressure in the filled container increases, the flow rate at which the liquefied gas is filled, that is, the momentum at which the liquefied gas is filled in the filled container gradually decreases. The change in the flow rate from the beginning of filling to the point when the filling is almost full is measured, and the flow rate when the filling is completed (full tank) is set as the first predetermined flow rate value. When the flow rate (momentum) at which the liquefied gas is filled is reduced to be equal to or lower than the first predetermined flow rate value, it is determined that the liquefied gas in the filled container has become full, and the filling flow rate is decreased. By setting in this way, it is possible to fill up with a large flow rate, that is, vigorously until full tank is reached, and after reaching full tank level, reduce the flow rate to be filled, that is, reduce the momentum to fill. Can do. When filling is completed, that is, when the filled container is full, the overfill prevention valve provided on the filled container side is closed, and filling to the filled container side is stopped. When this overfill prevention valve is closed, a so-called water hammer phenomenon occurs, and when the flow rate of the liquefied gas to be filled is large, the impact of the water hammer adversely affects each device in the filling device. Therefore, by reducing the flow rate of the liquefied gas to be filled when the tank is full, the adverse effects due to the impact of the water hammer are prevented from occurring in each device.

  Further, the invention of the liquefied gas filling device according to claim 2 is the invention according to claim 1, wherein the flow rate control means is configured such that the flow rate measured by the flow rate measuring means at the start of filling of the liquefied gas is When the flow rate is equal to or smaller than the second predetermined flow rate value smaller than the first predetermined flow rate value, the liquefied gas is filled without adjusting the flow rate adjusting valve for reducing the flow rate of the liquefied gas. It is characterized by making it.

  If the flow rate of the liquefied gas to be filled is decreased, the time required for completing the filling is increased accordingly. Even if the time to decrease the flow rate is full (whether filling is complete), the time increases similarly. The reason why the filling flow rate is reduced in the middle is to prevent problems caused by the impact of the water hammer as described above. Therefore, it is not always necessary to reduce the filling flow rate as long as the impact does not cause a problem. Therefore, when the initial flow rate at which the filling of the liquefied gas into the filled container is a value that does not cause a problem to the device or the like due to the water hammer phenomenon due to the flow rate (below the second predetermined flow rate value), No adjustment was made. For example, when the filling flow rate measured after the start of filling does not increase because the pressure in the filling device is high, and the flow rate is less than or equal to the second predetermined flow rate value, the flow regulating valve for reducing the flow rate No adjustment was made. As a result, when the filling is a small flow rate (second predetermined flow rate value or less), it is possible to prevent an increase in filling time associated with a decrease in the flow rate.

  According to the liquefied gas filling apparatus according to the present invention, the filling of the liquefied gas into the filled container is completed, and by the overfilling prevention valve on the filled container side that is closed at the end of filling by reducing the liquefied gas filling flow rate. The adverse effect of the water hammer can be greatly suppressed, and the liquefied gas can be measured safely and reliably. In addition, an unnecessary increase in the filling time can be prevented by adopting a configuration in which the flow rate is reduced only in the case of a filling flow rate at which a malfunction due to a water hammer can occur.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a liquefied gas filling apparatus according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a system diagram showing a liquefied gas filling device 1. The liquefied gas filling device 1 is installed in a gas supply station or the like, and is a device that supplies the liquefied gas stored in the storage container 3 to the vehicle container 2 (filled container) mounted on the vehicle. Examples of the liquefied gas include liquefied DME (dimethyl ether), LPG (liquefied propane gas), and LNG (liquefied natural gas).

  The liquefied gas filling device 1 is schematically configured from a dispenser unit 4, each device mounted on the dispenser unit, and a control unit 5 that controls each device and the like. A liquid line 6 (liquefied gas filling path) communicating with the storage container 3 is connected to the dispenser unit 4. In the liquid line 6 of the liquefied gas filling device 1, a separator 7, a check valve 8, a flow meter 9 (flow rate measuring means), a back pressure valve 10, a pressure gauge 11, and an electromagnetic valve 12 are sequentially arranged downstream. Has been.

  The separator 7 functions as a gas-liquid separator, removes gas from the liquefied gas supplied from the storage container 3, and allows only the liquid to flow to the flowmeter side provided downstream. The check valve 8 prevents the backflow of the liquefied gas flowing from the storage container 3 through the liquid line 6 to the downstream side. The flow meter 9 measures the supply amount of the liquefied gas from the storage container 3 to the vehicle container 2, that is, the flow rate of the liquefied gas flowing through the liquid line 6. The measurement of the liquefied gas is continuously performed from the start of filling to the end of filling, and the measured flow rate value data is transmitted to the control unit 5 (flow rate control means).

  The back pressure valve 10 is a valve for keeping the upstream pressure at or above the pressure at which vaporization does not occur in order to prevent the upstream liquefied gas from being vaporized. As the pressure on the upstream side decreases and approaches the pressure at which vaporization can occur, the valve is closed to keep the upstream pressure at or above the pressure at which no vaporization occurs. The pressure gauge 11 is for allowing the operator to confirm the pressure by visual observation, and it is possible to infer abnormalities and operating states of the dispenser from the pressure value.

  The electromagnetic valve 12 is a flow rate adjustment valve that can change the flow path area, and adjusts the flow rate of the liquefied gas supplied to the vehicle container 2. The electromagnetic valve 12 is connected to the control unit 5, and the opening and closing of the valve is controlled by a control signal transmitted from the control unit 5. The solenoid valve 12 may be, for example, a variable throttle valve, and may have a configuration in which the flow area can be gradually reduced by restricting the valve to reduce the flow rate, or the flow area can be changed continuously by changing the flow area. It is also possible to use a configuration that can narrow down. The electromagnetic valve 12 used in this embodiment is an adjustment valve that can be completely closed by the control of the control unit 5 to adjust the flow rate to zero. Further, the solenoid valve 12 may be a flow rate adjustment valve that is controlled to open and close in order to switch the flow path of the liquefied gas, for example. A first flow path having a large flow path area, a second flow path having a small flow path area, and a first valve and a second valve for opening / closing each flow path are provided. To open and close the first valve and the second valve to change the flow rate.

  The controller 5 has a filling start switch 13 (filling start instructing means) for instructing the start of filling of liquefied gas, and a filling stop switch 14 (filling stop instructing means) for instructing to stop filling of liquefied gas. Is connected. The controller 5 controls the electromagnetic valve 12 in accordance with instructions from these switches 13 and 14 to control the filling flow rate.

  A filling hose 22 is connected downstream of the liquid line 6 via a safety coupling 21 that prevents leakage of liquefied gas. A filling nozzle 23 is provided at the tip of the filling hose 22, and this filling nozzle 23 is connected to the filling port of the vehicle container 2 to fill the vehicle container 2 with liquefied gas. An overfilling prevention valve 25 for preventing overfilling of the liquefied gas is provided in the vehicle container 2, and when the filled liquefied gas reaches a predetermined amount, for example, the vehicle container becomes full. When closed, the liquefied gas inlet is closed. By closing the overfill prevention valve 25, a so-called water hammer phenomenon occurs.

  The storage container 3 is provided with a pressure sensor 31 and a temperature sensor 32 for measuring the pressure and temperature in the storage container 3. The pressure sensor 31 and the temperature sensor 32 are connected to the control unit 5, and data of the storage container 3 measured by both the sensors 31 and 32 is transmitted to the control unit 5.

  The control unit 5 is composed of, for example, a CPU, and controls each device connected to the control unit in accordance with a program stored in a ROM built in the CPU to fill liquefied gas. Further, the data of each device, for example, the flow value measured by the flow meter 9, the data indicating the degree of opening and closing of the electromagnetic valve 12, etc. are written in the RAM built in the CPU, and read from the RAM as necessary. Used as control data.

Next, the operation of the liquefied gas filling apparatus 1 according to the present embodiment will be described based on the flowchart of FIG.
Here, the solenoid valve 12 used in this embodiment has a configuration in which the flow rate can be changed by switching the flow path of the liquefied gas, and a large flow rate, a small flow rate, a flow rate can be changed by the switched flow path. It can be changed to a three-stage filling flow rate of zero. In the following description, the flow path for large flow rate is referred to as a first flow path (main line), and the flow path for small flow rate is referred to as a second flow path (subline). A valve that opens and closes the main line is called a first valve (main line valve), and a valve that opens and closes the sub line is called a second valve (sub line valve). When the main line valve is opened (the sub line valve is closed) and the main line is used as a flow path for the liquefied gas, the flow rate of the filled liquefied gas is not reduced depending on the main line. When the sub line valve is opened (the main line valve is closed) and the sub line is used as a liquefied gas flow path, the flow rate of the liquefied gas to be filled is limited by the flow area of the sub line, and the vehicle container 2 The water hammer phenomenon due to the overfilling prevention valve 25 is reduced to a flow rate that does not have an adverse effect. Further, when both the main line valve and the sub line valve are closed, the filling of the vehicle container 2 becomes zero, that is, the measured value by the flow meter 9 becomes zero.

  First, in step 41, it is determined whether or not the filling start switch 13 is turned on. If it is determined that the filling start switch 13 is turned on, the process proceeds to step 42, the filling electromagnetic valve 13 is controlled, the main line valve is opened, and the main line is opened. On the other hand, if it is determined that the filling start switch 13 is not turned on, the determination process of step 41 is repeated.

  When the main line is opened, the process proceeds to step 43, where the flow rate value measured by the flow meter 9, that is, the flow rate charged from the storage container 3 to the vehicle container 2 is greater than a predetermined specified value A. It is determined whether or not the flow rate value is large. The measurement of the flow rate by the flow meter 9 is always performed during filling (between the filling start switch is turned on and the filling stop switch is turned on), and the measurement data is transmitted to the control unit 5. The specified value A here is a flow rate value (first value) that does not adversely affect each device in the filling device due to the impact when the water hammer phenomenon occurs when the overfill prevention valve 25 of the vehicle container 2 operates. 2 (predetermined flow rate value).

  When it is determined in step 43 that the flow rate is larger than the specified value A, that is, when it is determined that the water hammer phenomenon due to the operation of the overfill prevention valve 25 has occurred, the devices in the filling device are adversely affected. Advances to step 44. On the other hand, when it is determined that the flow rate is equal to or less than the predetermined value A, that is, when it is determined that the water hammer phenomenon caused by the operation of the overfill prevention valve 25 does not adversely affect each device in the filling device. , Go to Step 45.

  In step 44, it is determined whether or not the flow rate value measured by the flow meter 9, that is, the flow rate charged from the storage container 3 to the vehicle container 2 is equal to or less than a predetermined value B. The flow rate of the liquefied gas filled in the vehicle container 2 is such that when the vehicle container 2 is in a sealed state, the volume of the vaporized gas part (gas phase part) in the vehicle container decreases as the filling of the liquefied gas proceeds, As pressure increases, it gradually decreases. Therefore, the flow rate value measured by the flow meter 9 gradually decreases accordingly. Here, the prescribed value B refers to a flow rate value (first predetermined flow rate value) that is presumed that the filling of the liquefied gas into the vehicle container 2 has been completed. That is, in step 44, it is determined whether or not the measured value of the flow meter 9 has become equal to or less than the flow rate value (specified value B) estimated that the vehicle container 2 is completely filled. The term “filling of liquefied gas” here means when the overfill prevention valve provided in the vehicle container 2 is closed, that is, when the water hammer phenomenon occurs. The specified value A and the specified value B are in a relationship of specified value A <specified value B.

  If it is determined that the flow rate value measured by the flow meter 9 has become equal to or less than the specified value B, that is, if it is determined that the vehicle container 2 has been completely filled, the process proceeds to step 46 and the electromagnetic valve for filling is performed. 12 is controlled, the main line valve is closed and the sub line valve is opened, so that the main line is in the “closed” state and the sub line is in the “open” state. As a result, the flow path of the liquefied gas filled in the vehicle container 2 is switched to the subline, the flow rate is limited to the flow area of the subline, and the water hammer phenomenon by the overfill prevention valve 25 of the vehicle container 2 causes each device to Reduced to a flow rate that does not cause a malfunction. On the other hand, if it is determined that the flow rate value is greater than the specified value B, the determination process of step 44 is repeated until the flow rate becomes equal to or less than the specified value B.

When the filling flow rate decreases in the processing of step 46, it is determined whether or not there is a flow pulse in step 47, that is, whether or not the flow meter 9 detects the flow rate of the liquefied gas and the detection pulse is transmitted to the control unit 5. Is done. When it is determined that there is no flow rate pulse, that is, when the filling of the liquefied gas into the vehicle container 2 is completed and the flow rate is not detected by the flow meter 9, the process proceeds to step 48 and the electromagnetic valve 12 for filling is turned on. Close (close both the main line valve and the subline valve) to finish the filling process. As described above, when filling of the liquefied gas in the vehicle container 2 is completed, the overfill prevention valve 25 is closed. By closing the overfill prevention valve 25, the filling from the storage container 3 side to the vehicle container 2 side is stopped, and the flow rate is not detected by the flow meter 9. Further, the water hammer phenomenon occurs when the overfill prevention valve 25 is closed. However, since the filling flow rate is reduced in step 46, there is no problem with each device.
On the other hand, when it is determined that there is a flow rate pulse, that is, when it is determined that the liquefied gas is continuously charged, the process of step 47 is repeated.

  When it is determined in step 43 that the flow rate is equal to or less than the specified value A and the process proceeds to step 45, it is determined whether or not there is a flow pulse, that is, the flow meter 9 detects the flow rate of the liquefied gas and the detection pulse is transmitted to the control unit 5. It is determined whether or not it is. If it is determined that there is no flow rate pulse, that is, if it is determined that the flow rate of the liquefied gas cannot be detected, the process proceeds to step 48, the filling electromagnetic valve 12 is closed, and the operation of the filling process is terminated. On the other hand, if it is determined that there is a flow rate pulse, that is, if it is determined that the flow rate is equal to or less than the specified value A but is filled with liquefied gas, the process returns to step 43 to perform the same processing as above. . When the flow rate is continuously filled at the specified value A or less, the processing in step 43 and step 45 is repeated until the filling is completed. Accordingly, when the filling flow rate measured by the flow meter 9 is, for example, the filling flow rate at the start of filling at which the measured value becomes the maximum (while a short period of time has elapsed from the start) is equal to or less than the predetermined value A, that is, If the water hammer phenomenon due to the flow rate does not adversely affect each device in the filling device, the filling process is performed in the main line “open” state without adjusting the solenoid valve 12 for reducing the flow rate of the liquefied gas. Done.

  In the above description, a flow rate adjustment valve (main line valve, subline valve) that changes the flow rate of the liquefied gas by switching the flow path is used as the electromagnetic valve 12. However, the present invention is not limited to this form. The solenoid valve 12 is provided in the liquid line 6 without switching, and is composed of a variable throttle valve. The valve is variably adjusted stepwise or continuously in accordance with a control signal from the control unit 5 and is filled. A flow rate adjustment valve capable of changing the flow rate of gas may be used.

It is a system distribution diagram showing one form of a liquefied gas filling device concerning the present invention. It is a flowchart which shows the filling control content of the control part of FIG.

Explanation of symbols

1 Liquefied gas filling device 2 Vehicle container (filled container)
3 Storage container 5 Control unit (flow rate control means)
6 Liquid line 9 Flow meter (Flow rate measuring means)
12 Solenoid valve (flow adjustment valve)
13 Filling start switch (filling start instruction means)
25 Overfill prevention valve

Claims (2)

In the liquefied gas filling device having a filling path for filling the liquefied gas into the filling container,
Filling start instruction means for instructing the start of filling of the liquefied gas;
A flow rate measuring unit that is provided in the filling path and measures a flow rate of the liquefied gas filled in the filled container when the filling of the liquefied gas is started by operating the filling start instruction unit;
A flow rate adjusting valve provided in the filling path for adjusting the flow rate of the liquefied gas flowing through the filling path;
By adjusting the flow rate adjusting valve when the flow rate measured by the flow rate measuring means becomes equal to or lower than a first predetermined flow rate value due to the pressure in the filled container that rises with the filling of the liquefied gas, A liquefied gas filling device comprising: a flow rate control means for reducing the flow rate of the liquefied gas. When the flow rate measured by the flow rate measuring unit at the start of filling of the liquefied gas is equal to or less than a second predetermined flow rate value smaller than the first predetermined flow rate value, 2. The liquefied gas filling device according to claim 1, wherein the liquefied gas is filled without adjusting the flow rate adjusting valve for reducing the flow rate of the liquefied gas.

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