JP3061096B2 - Liquefied gas meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a flow rate of a liquefied gas containing a plurality of components such as LPG.

[0002]

2. Description of the Related Art A liquefied gas is prepared by mixing a plurality of different components such as propane and n-butane. And propane has a low boiling point and a relatively high price, and butane has a relatively high boiling point and a low price.Therefore, the proportion of butane is high in high-temperature regions, and propane is used in low-temperature periods and regions. The composition of the ingredients differs depending on the region and season. For this reason, in the liquefied gas metering device, a temperature correction table of a liquefied gas having a certain density to be measured at the time of installation is set, and the flow rate measured based on this temperature correction table is set to a standard state, for example, a flow rate at 15 ° C. It is configured to convert. The correction data is set by a sealable dip switch or the like in order to prevent inadvertent changes.For example, when the mixing ratio of propane and butane, which is a component, is changed according to the season, However, there is a problem in that the density of the liquefied gas changes, and a large-scale verification operation must be performed each time.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to measure at an arbitrary temperature by a simple operation irrespective of the fluctuation of the components. An object of the present invention is to provide a novel liquefied gas metering device capable of accurately correcting a flow rate of a liquefied gas to a flow rate at a standard temperature and displaying the corrected value.

[0004]

To SUMMARY OF THE INVENTION <br/> order to achieve the above object, the other end is connected to a flow meter in the middle of the pipe to the filling nozzle connected to the liquid supply tank is connected In the liquefied gas metering device, the filling nozzle is connected to a flow meter.
With at least three liquids in the wetted area in the middle of the pipeline
And the incident light and the reflected light are parallel
A prism configured as described above and a temperature sensor for detecting the temperature of the liquefied gas are provided, and the light amount ratio between the incident light amount and the return light amount of the prism and the temperature in the standard state based on the temperature from the temperature sensor. Density calculating means for calculating density; volume conversion coefficient calculating means for obtaining a volume conversion coefficient based on the temperature and the density; calculating means for multiplying the data of the flow meter by the volume conversion coefficient; and to a display unit for displaying the output of.
The density is accurately measured on the three surfaces of the prism based on the refractive index of the liquefied gas, and a volume conversion coefficient is calculated based on the density to correct the data of the flow meter.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention. In the drawing, reference numeral 1 denotes a positive displacement flowmeter using a piston or the like. The discharge port of the installed pump 4 is connected, the liquid supply pipe 5 is connected to the outlet, and the filling nozzle 7 is connected via the pressure-resistant hose 6, and the flow rate of the liquid flowing through the liquid supply pipes 2 and 5 is controlled. The flow rate pulse transmitter 8 is configured to output a flow rate pulse to a control device 11 described later.

Reference numeral 11 denotes a control unit, which is a flow rate pulse transmitter 8
Pulse from the sensor, prism 9 and temperature sensor 1
It is configured to calculate the flow rate in the standard state based on the signal from 0 and display it on the display 12.

FIGS. 2A and 2B show one embodiment of the above-described prism. In FIG. 1A, reference numeral 9 denotes three surfaces 9a in the liquid contact area.
The prisms 9b and 9c are formed, and the incident beam L1 from the first light guide material 13 such as an optical fiber whose exit port is disposed opposite to the other end is reflected by three surfaces, and emitted parallel to the incident beam L1. It is configured to be incident on the light guide member 14 disposed on the other side as a beam L2.

FIG. 2 (b) shows a structure in which a liquid contact area is formed by a prism 15 having a semicircular cross section, and two light guide members for incident and outgoing light are respectively provided at one end. 16 and 17 are arranged so that the light beam L1 incident from the light guide 16 is reflected at three places of the prism 15 so that the light beam L2 parallel to the incident light beam L1 is incident on the other light guide 17. Is configured.

[0009] 3 By adopting such a configuration, the density of the fluid wetted the prism 12 and 15, and the refractive index of the optical material constituting the prism, as amount of light caused by the difference between the refractive index of the liquid Times can be detected. That is,
Light quantity affected over three times coming returning from the light guide member 14, 17 by the density of the liquid, ensures slight change in density
Can be detected as a change in the amount of light.

FIG. 3 shows an embodiment of the control device 11 described above. In the figure, reference numeral 20 denotes a light emitting means for generating a light beam for measurement, and reference numeral 21 denotes a light returning from the prism 9. This is a light receiving means for measuring the intensity of the reflected light. Reference numeral 22 denotes a temperature calculation unit that calculates the temperature of the liquid based on a signal from the temperature sensor 10.

Reference numeral 23 denotes a density calculating means for converting a signal representing the light quantity R2 of the light L2 received by the light receiving means 21 into a ratio R2 / R1 of the light L1 incident on the prism 9 from the light emitting means 20 to the light quantity R1. And this ratio R2 / R1,
The first storage means 24 described below is accessed with the measured temperature T determined by the temperature calculation means 22 and the density of the liquid in a standard state is calculated and output based on the data stored therein. Have been.

Reference numeral 24 denotes the first storage means, as shown in Table 1, a measured temperature and a relative return light amount corresponding to the measured temperature, that is, a ratio of the light amount R1 of the incident light L1 to the light amount of the return light L2. The density is measured in correspondence with R2 / R1, and the result of conversion into a standard state is stored.
In Table 1, measured temperatures at every 10 ° C. are stored. For other temperatures, it is possible to obtain the density in a standard state at any temperature with sufficient accuracy for practical use by performing an interpolation operation. it can.

[0013]

[Table 1]

Reference numeral 25 denotes a volume conversion coefficient calculating means for accessing data in a second storage means 26 described later based on the measured temperature from the temperature calculating means 22 and the density in the standard state from the density calculating means 23. It is configured.

Reference numeral 26 denotes the above-mentioned second storage means for storing the density in the standard state defined by JIS as shown in Table 2 and the volume conversion coefficient at the measurement temperature, that is, the sample temperature at the time of volume measurement. It is configured.

[0016]

[Table 2]

Numeral 28 denotes a calculating means, which is a flow pulse transmitter 8
The data of the counting means 27 for integrating the flow rate pulses from the multiplication unit is multiplied by a volume conversion coefficient and output to the display unit 12.

Next, the operation of the above-configured apparatus will be described. When the liquid is supplied by connecting the nozzle valve 7 to the vehicle fuel tank, a flow pulse is output from the flow pulse transmitter 8 in proportion to the discharge flow, and the flow pulse is integrated by the counting means 27. In parallel with this liquid supply operation, the control device 11
Activates the light emitting means 20 to cause the prism 9 to emit the light beam L
1 is incident. The light beam L1 is applied to each surface of the prism 9 by the refractive indexes n ₀ and LP of the optical glass constituting the prism 9.
The light G is reflected at a reflectance determined by a refractive index n ₁ based on the density at the current temperature, is incident on the light receiving unit 21 with a light amount related to the density of the LPG, and is converted into a ratio R2 / R1 with respect to the incident light amount. The density calculator 23 calculates the LP calculated by the temperature calculator 22 based on the signal from the temperature sensor 10.
G based on the current temperature of G and the light amount ratio R2 / R1.
The density of the LPG in the standard state is calculated from the storage means 24.

For example, if the current temperature T of the LPG is 25 ° C.
When the light amount ratio R2 / R1 is 0.995, data of 0.530 is obtained as the LPG density in the standard state.

The volume conversion coefficient calculating means 25 reads the density in the standard state 0.530 obtained in this way and the current temperature 25 ° C. of the LPG obtained by the temperature calculating means 22 from the second storage means 26. Applicable volume conversion factor 0.9
Find 74.

The calculating means 28 multiplies the data of the counting means 27 by the volume conversion coefficient 0.974 obtained by the volume conversion coefficient calculating means 25 and outputs the result to the display 12. As a result, the supply amount converted to the standard state is displayed regardless of the density and temperature of the LPG.

[0022] Incidentally, Oite to the embodiments described above is a temperature sensor, and a density detector is provided in the supply pipe, it is clear that to obtain the same effect be provided to the tank.

In the above-described embodiment, the density is calculated every time the liquid is supplied. However, when the liquid supply device is installed, or when the composition of the LPG is changed, the density is calculated. A conversion coefficient is set as in the case or the density is obtained only when the check is performed, and this is stored in the storage means, and this density is output to the volume conversion coefficient calculation means every time the liquid is supplied. Obviously, the same effect is obtained even if it does so.

[0024]

As described above, according to the present invention, the prism provided so as to be in contact with the liquefied gas, the temperature sensor for detecting the temperature of the liquefied gas, and the light quantity between the incident light quantity and the output light quantity of the prism A density calculating means for calculating a density in a standard state based on the ratio and the temperature from the temperature sensor; a volume conversion coefficient calculating means for obtaining a volume conversion coefficient based on the temperature and the density; Since it has a calculating means for multiplying the conversion coefficient and a display means for displaying the output from now on, the light amount of the liquefied
Reliable detection of small density changes under the influence of density
Thus , the liquid amount in the standard state can be accurately obtained regardless of the component ratio of the liquefied gas.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating an embodiment of a density detecting unit. FIG.

FIG. 3 is a block diagram showing one embodiment of a control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow meter 3 Liquefied gas storage tank 5 Supply pipe 5 Return pipe 8 Flow pulse transmitter 9 Prism 10 Temperature sensor 11 Control device 12 Display

Claims (1)

(57) [Claims] 1. A liquefied gas measuring device comprising a flow meter connected in the middle of a pipe to which a filling nozzle having one end connected to a liquefied gas storage tank and the other end connected to a liquid supply tank is provided. In the middle of the pipe connecting the flow meter,
A reflective surface associated with at least three liquids in the liquid region;
And a projector configured so that incident light and reflected light are parallel.
Temperature sensor for detecting the rhythm and the temperature of the liquefied gas
And a light intensity ratio between an incident light amount and a return light amount of the prism, and a density calculating unit that calculates a density in a standard state based on a temperature from the temperature sensor, and based on the temperature and the density. A liquefied gas meter comprising: a volume conversion coefficient calculating means for obtaining a volume conversion coefficient; a calculating means for multiplying the data of the flow meter by the volume conversion coefficient; and a display means for displaying an output of the calculating means.