JP2501544B2 - Wireless liquid amount measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless liquid amount measuring device suitable for remotely controlling the liquid level and liquid amount of an underground tank buried in a gas station or the like.

[0002]

2. Description of the Related Art A liquid level of fuel oil or the like stored in an underground tank is usually converted into an electric signal by a float type level gauge, and this electric signal is monitored through a transmission line in an office or the like. It is managed by transmitting it to the device.

In such a system, the line connecting the float type liquid level gauge to the monitoring device needs to be installed with explosion-proof treatment, which causes a problem of construction cost.

In order to solve such a problem, the applicant of the present invention has previously proposed a wireless liquid level measuring device capable of transmitting a liquid level signal from a float type liquid level gauge by a wireless signal (Japanese Patent Laid-Open No. Hei 10 (1999) -242977).
2-176425) was proposed.

Since this wireless liquid amount measuring device is arranged very close to the tank and uses a battery as a power source, it is assembled in a factory in a state where the battery is built in and hermetically sealed, and is directly assembled. Has been shipped.

For this reason, a radio signal is output at a predetermined cycle, which causes interference when assembling and adjusting in a factory, causes radio wave interference, and when installing a plurality of devices. Has a problem that radio waves from other wireless liquid amount measuring devices interfere with the adjustment work.

In order to solve such a problem, it is conceivable to provide an electromagnetic shield to the packaging case or to separately provide a power switch so as to cut off the power supply from the battery when not installed, but this increases the packaging cost. There is a problem that it invites or requires a special switch with a seal mechanism so that it can be operated externally.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to use unnecessary radio waves without requiring a special packaging case or power switch. Another object of the present invention is to provide a wireless liquid amount measuring device capable of stopping the transmission of the liquid.

[0009]

In order to solve such a problem, in the present invention, an electric signal is received by receiving the vertical movement of the float in response to the liquid level through a connecting member for transmitting the movement of the float. A means for converting the electric signal as a radio signal, a transmitting means for operating the transmitting means in a predetermined cycle, and the transmitting means of the transmitting means when the connecting member is pulled out to a specific position. The control means for stopping the operation is provided.

[0010]

DETAILED 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 which a microcomputer 1 constituting a control means receives an operating power from a battery 3 at a power supply terminal 1a via a voltage regulator 2 and a voltage regulator 2 The activation signal from the timer means 4 which is constantly supplied with electric power is received by the activation signal terminal 1b, and operates intermittently at a cycle T0 determined by the timer means 4.

The timer means has a fixed period T0, for example, 1
Microcomputer 1 outputs a start signal at intervals of 5 seconds
Is designed to operate.

The data storage means 6 includes a voltage regulator 2
Is constantly supplied with operating power via the liquid level measuring means 7 and takes in the liquid level, which is the previous liquid level F0,
In addition, the numbers Nx and Ny described later are stored, and data indicating the transmission stop liquid level Fx lower than the minimum liquid level of the underground tank for setting the transmission stop mode and the transmission stop release for canceling the transmission stop mode are set. It is configured to store data indicating the liquid level Fs.

The liquid level measuring means 7 is connected to a float 8 installed in a tank, one end of which is connected to the float 8 and the other end of which is a scale tape 9 wound around a tape reel 10 and a tape reel 10. A potentiometer 11
A voltage-frequency conversion means 12 for converting the output voltage from the potentiometer 11 into a frequency, and the potentiometer 11
And a voltage regulator 13 for supplying a reference voltage to
The operating power is supplied through a first switch 5 controlled by the microcomputer 1, and a frequency signal corresponding to the amount of the scale tape 9 pulled out, that is, the liquid level is output. In this embodiment, the scale tape 7 functions not only as a liquid level display member but also as a float 8.
It also functions as a connecting member that transmits the vertical movement of the to the potentiometer 11.

The modulation means 14 is the microcomputer 1.
The operating voltage is supplied from the voltage regulator 2 via the second switch 15 controlled by the above, and the liquid level from the liquid level measuring means 7 is transmitted from the antenna 16 as a radio signal.

Next, the operation of the thus constructed apparatus will be described with reference to the flow charts shown in FIGS.
When the battery 3 is housed and assembled in a factory in an operable state, the microcomputer 1 stands by in a standby state, leaving only a function that can be activated when receiving the activation signal from the timer means 4. The timer means 4 is constantly supplied with electric power from the battery 3 to perform a time-dependent operation (step a), and outputs a start signal every time the time T0 elapses (step b). As a result, the microcomputer 1 leaves the standby state and shifts to the operating state, turns on the first switch 5 and supplies the operating power to the liquid level measuring means 7 (step C).

The liquid level measuring means 7 converts the current liquid level into a voltage by the potentiometer 11, converts this voltage into a frequency by the voltage-frequency conversion means 12, and outputs it to the microcomputer 1. The microcomputer 1
This frequency signal is counted for a certain period of time to obtain the liquid level F1 (step d), the first switch 5 is turned off to cut off the power to the liquid level measuring means 7, and the liquid level F1 and the transmission stop liquid level Fx are obtained. To compare. Scale tape 9 as connecting member
If is drawn to a position other than the transmission stop liquid level Fx and the transmission stop release liquid level Fs, that is, the position of the normal measurement mode, the liquid level F1 is not the data indicating the transmission stop liquid level Fx and the near equal. Since the data indicating the transmission stop release liquid level Fs is neither near-equal (step F) (step F), the transmission stop is not stored in the data storage means 6, and steps (H) and (R) and subsequent steps are performed. Go into action.

The microcomputer 1 compares the data of the measured liquid level F1 with the data of the previous liquid level F0 stored in the data storage means 6 (step
Re). In this case, the scale tape 9 has just been assembled and is in a stopped state at the wound position, and the measured liquid level F1 is the same as the previous liquid level F0 of the data storage means 6. (Step Nu).

Since it is the first measurement, the numerical value N is "0" (step). Therefore, the microcomputer 1 turns on the second switch 15 to operate the transmission modulation means 14 to transmit the liquid level F1. Then, after the transmission is completed, the second switch 15 is turned off to stop the transmission (step E). Then, set a numerical value N to the transmission interval, for example
0 "is set (step W), the liquid level F0 of the data storage means 6 is updated with the liquid level F1 of this measurement, and the standby state is entered (step C). This shuts down the entire system, leaving only the minimal functionality needed for the next start-up, minimizing power consumption.

When the timer means 4 measures the time T0 (step a) and the next start signal is output, the microcomputer 1 executes the operations of steps (b) to (l) as described above. In this case, since the numerical value N was set to "10" in the previous process and the numerical value N is not "0" (step), the numerical value N is decremented by 1 (step yo), and the liquid level data is obtained. The previous liquid level F0 of the data storage means 6 is updated with this liquid level F0 without transmission, and then the standby state is entered (step C).

When the above operation is repeated 10 times (steps I to Y, Y and K) and the numerical value N becomes "0" (step), the microcomputer 1 determines that the second switch 1
5 is turned on to supply electric power to the modulation transmission means 14 to transmit the liquid level F1 of the liquid level measurement means 7, and after the transmission, the second switch 15 is turned off (step o), and the transmission interval "10" is set as the numerical value N. Reset ”(step
Wa). Then, the previous liquid level F0 is updated to the current liquid level F1 and the standby state is set (step C), and the above process is repeated. After that, the liquid from the liquid level measuring means 7 is transmitted as a radio signal as in the case where the liquid is actually installed in the tank.

When the transmission stop mode is set, the scale tape 9 is pulled out to a position corresponding to the preset transmission stop liquid level Fx. In this state, when the next activation signal is output from the timer means 4 (step B) and the microcomputer 1 is activated, the microcomputer 1
The liquid level F1 from the liquid level measuring means 7 is compared with the data of the transmission stopped liquid level Fx of the data storage means 6 (step
F) Detecting that the scale tape 9 has been pulled out to the transmission stop position, add “1” to the numerical value Nx, and set the numerical value Ny.
Is reset to “0” (step). At this point, the numerical value Nx is "1" (step re), so the procedure returns to step (ii).

When such an operation is executed three times, the numerical value Nx becomes "3", and the transmission stop is stored in the data storage means 6 (step S). When the transmission stop is stored in the data storage means 6, even if the scale tape 9 is returned to the original position, the step (b) returns to the step (b), so that the liquid level is not transmitted. That is, in order to enter the transmission stop mode, the scale tape 9 may be continuously pulled out to the transmission stop liquid level Fx for a period of time three times the time T0 or more to store the transmission stop. As a result, the emission of radio waves is stopped, and the consumption of the battery 3 can be suppressed.

In order to cancel the transmission stop, when the scale tape 9 is pulled out to the transmission stop release liquid level Fs, the microcomputer 1 receives the start signal and operates, and step (g)
And compares the liquid level F1 from the liquid level measuring means 7 with the transmission stop release liquid level Fs of the data storage means 6 to detect that the scale tape 9 has been pulled out to the transmission stop release position,
"1" is added to the numerical value Ny, and the numerical value Nx is reset to "0" (steps). And at this point the number N
Since y is “1” (step N), move to step (A). When this operation is executed 3 times, the numerical value N
When y becomes "3", the transmission stop stored in the data storage means 6 is erased (step N). That is, to cancel the transmission stop, the scale tape 9 is used to release the transmission stop liquid level Fs.
It is sufficient to erase the transmission stop of the data storage means 6 by continuously pulling out for more than three times T0.

In this way, in order to stop the transmission and release it, the scale tape 9 is held at the liquid levels Fx and Fs for a certain period of time or more. This is because.

When the transmission stop is released and the fuel tank is installed in the underground tank of the gas station, the fuel oil is pumped out by the fueling device, and the liquid level of the underground tank lowers. Therefore, the process moves from step (nu) to step (ru). The transmission interval value N "10" is decremented and the liquid level F1 is transmitted every "0".

Further, while the fuel oil is being replenished to the underground tank by the lorry, the liquid level rises, and therefore the process moves from step (n) to step (e), and the liquid level F1 is changed every time the microcomputer 1 is activated. Sent.

That is, when the liquid level in the underground tank is constant or has dropped, a cycle ΔT1 longer than the start cycle ΔT0 of the microcomputer 1 (III in FIG. 5).
In addition, when the tank is being replenished with liquid by the tank truck, the starting cycle ΔT0 of the microcomputer 1
(IV in FIG. 5), the modulation transmission means 14 operates to transmit the liquid level in the tank.

In this embodiment, when the scale tape 9 is completely pulled out from the tape reel 10, the transmission is stopped and released. However, as shown in FIG. When the scale tape 9 is wound up to the liquid levels Fs and Fx, it may be stopped and released. Further, even if the scale tape 9 is reciprocated at a reference position within the measurement range at a high speed that cannot occur with a normal liquid level fluctuation, and this is detected, the same operation is achieved.

Further, in this embodiment, in the transmission stop mode, the power supply to only the modulation transmission means is cut off. However, the power supply to the liquid level measurement means is also cut off to reduce the consumption of the battery. can do.

[0030]

As described above, in the present invention, means for receiving the vertical movement of the float in response to the liquid level through the connecting member for transmitting the movement of the float and converting it into an electric signal, and an electric signal. Is provided as a radio signal, and a control means for operating the transmitting means in a predetermined cycle and stopping the operation of the transmitting means when the connecting member is pulled out to a specific position. ,
Unnecessary emission of radio waves can be prevented and battery consumption can be suppressed without using a power switch or an electromagnetic shield case.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing an operation of the same apparatus.

FIG. 3 is a flowchart showing the operation of the above apparatus.

FIG. 4 is a front view showing an embodiment of a scale tape.

FIG. 5 is a timing diagram showing an operation cycle of the same device.

FIG. 6 is a view showing another embodiment of the present invention with a tape pull-out amount.

[Explanation of symbols]

 7: Liquid level measuring means 9: Scale tape as a connecting member 11: Potentiometer 16: Antenna

Claims (1)

(57) [Claims] 1. A means for receiving a vertical movement of a float in response to a liquid level through a connecting member for transmitting the movement of the float and converting it into an electric signal, and a transmitting means for outputting the electric signal as a radio signal. A wireless liquid amount measuring device, comprising: a control unit that operates the transmission unit in a predetermined cycle and that stops the operation of the transmission unit when the connecting member is pulled out to a specific position.