JPH0719930A - Method and device for measuring level height - Google Patents

Abstract

PURPOSE:To calculate the level height of a liquid requiring sealing property such as a fused metal by blowing an inert gas from a prescribed depth, and detecting the variation of the blowing pressure of the inert gas the following the variation of the level height. CONSTITUTION:From a bomb 1 in which an inert gas such as liquid nitrogen is housed, the gas having a pressure of 2kg/cm<2> is blown into a fused metal in an 1-ml/sec storing furnace 3 through a hose 2 by a blowing pipe 10. Since the gas pressure at this time is proportional to the height H with the fused metal surface in the blowing position, the fused metal height can be quickly known by measuring the blowing pressure of the gas, when a standard height is preliminarily measured, When the input side of a pressure converter 4 is connected to the hose 2, and the output side of the converter 4 to the input side of a digital indicator 5, the variation of the blowing pressure of the inert gas can be digitally read.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level measuring method and apparatus for measuring the level of a molten metal, a gasoline storage underground tank, or the like.

[0002]

2. Description of the Related Art Conventionally, the height of a molten metal surface is mainly determined by visual observation. In addition, for the water surface and the like, there is known a technique of controlling the upper and lower limits by using a transparent tube provided outside the tank or by using an electrode rod. Further, a method of detecting the water surface position using electromagnetic means is also known.

[0003]

Among the above-mentioned conventionally known technical means, not only continuous detection is impossible by visual observation, but also in the case of molten metal, there is a risk of impairing the tightness of the melting furnace. There was a problem.

Next, the installation of the transparent tube applying the principle of the U-shaped tube is not only restricted by the liquid used, but often depends on visual observation, and the installation location is easily restricted, and this is avoided. However, there is a problem that the whole structure tends to have a complicated structure.

Further, when an electrode rod is used, it is difficult to know the fluctuation of the liquid level in detail, and it cannot be used for a liquid (for example, gasoline) which may cause sparks due to an electric means, and The high temperature liquid (molten metal) has a number of problems such as electromagnetic measurement means being unable to be used because of electromagnetic variation.

[0006]

According to the present invention, however, the height of the liquid surface is calculated by discharging the inert gas at a predetermined depth in the liquid and measuring the discharge pressure of the inert gas. Is solved.

That is, the invention of the method blows out the inert gas from a predetermined depth in the liquid, detects the fluctuation of the blowing pressure of the inert gas due to the fluctuation of the height of the liquid surface, and measures the measured liquid surface based on the blowing pressure. It is a liquid level height measuring method characterized by calculating the height of the liquid. Further, another invention is one in which the blowout pressure is converted into an electric output, and the inert gas is characterized by being inactive with the liquid to be measured.

Next, in the invention of the apparatus, the upper end of the gas pipe which is inserted into the liquid and blows out the inert gas from the lower end thereof is connected to the discharge port of the inert gas cylinder by the gas supply hose, and the gas supply is performed. A liquid level height measuring device characterized in that a pressure-electricity conversion display means is connected to a hose.

In the above description, the inert gas means, for example, nitrogen gas, argon gas, helium gas, etc., and it is essential that the inert gas is inert to the liquid to which the present invention is applied.

The pressure-electricity conversion display means is, for example, a digital meter relay connected to the output of the pressure transmitter. The pressure transmitter measures a small amount of pressure and outputs it to 4 to 20 mADC or 1 to 5 mADC.
The digital meter relay is a meter that converts into an electrical signal of VDC and transmits it. The digital meter relay is a digital meter with a 31/2 digit LED display and a digital comparator relay with a high-low two-stage setting digital comparator.

Therefore, in response to a minute change in the pressure of the inert gas according to the present invention, a minute pressure fluctuation is detected, converted into an electric output, and the detected value is digitally displayed.
Therefore, if converted into height display, the liquid level height can be known immediately.

According to the present invention, it is possible to easily detect, at a remote location, the level of the molten metal or the level of the underground tank of the gasoline storage at a gas station, which has conventionally relied on visual observation.

With regard to the height of the molten metal surface, remote automatic control is easy if the upper and lower limits of the molten metal surface are set according to a predetermined set value. As a result, if a fixed amount of molten metal is constantly stored in the storage furnace or the like, the supply condition of the molten metal can be kept constant during use, and the homogeneity of the product can be improved. The pressure-electrical signal converter in the invention of the above device is arranged near the gas cylinder of the inert gas, but a device for digitally displaying an electric signal such as a digital meter relay can be placed in a remote place. It can be aggregated together.

[0014]

In other words, according to the present invention, since the inert gas is discharged below the liquid surface and the discharge pressure is detected to calculate the height of the liquid surface, the temperature of molten metal hot water, gasoline or other special liquid The surface height can be detected easily and at a remote location, and a corresponding command can be issued and automatic control can be performed.

[0015]

[Example 1] 1 to 2 kg of a gas cylinder containing liquid nitrogen
Nitrogen gas at a pressure of / cm ² is blown out through the hose 2 into the molten metal (eg, aluminum molten metal) of the storage furnace 3 at a volume of 1 ml per second. The pressure of the nitrogen gas at this time is proportional to the height of the surface of the molten metal at the blowing position. I can know.

In the above, if the input side of the pressure converter 4 is connected to the hose 2 and the output side of the pressure converter 4 is connected to the input side of the digital display 5, fluctuations in the blowing pressure of nitrogen gas are digitally displayed. Can be read as If the output of the digital display 5 is used as the input of the pump 6, the pump 6 can be started when necessary and the molten metal in the melting furnace 11 can be transferred to the required amount storage furnace 3.

[0017]

[Embodiment 2] A hose 2 of a cylinder 1 is connected to a blow pipe 10 installed upright in a storage furnace 3, and a throttle valve 7 is connected to the hose 2.
And the hose 8 of the pressure-electricity converter 4 is connected, and the electric wire 9 of the pressure-electricity converter 4 is connected to the digital display 5
Connect to.

In the above embodiment, the throttle valve 7 is appropriately throttled so that the amount of blown nitrogen gas is small and constant.

Next, when the nitrogen gas is discharged into the storage furnace 3, the height of the molten metal surface can be known immediately from the blowing pressure.

That is, since the height H of the molten metal is proportional to the blowing pressure, the height of the molten metal can be easily known by measuring the blowing pressure.

Since the digital display and the pressure-electricity converter described above are connected by electric wires, their length can be freely controlled and remote control is easy. According to the result of the experiment, the height of the molten metal could be measured with an accuracy of ± 5 mm.

[0022]

According to the present invention, the inert gas is blown into the liquid to be measured, the gas pressure is measured, and the liquid level is converted based on the measured gas pressure. However, there is an effect that the liquid level can be measured easily, safely, reliably and continuously.

However, if the gas pressure is electrically converted into a digital display, remote control is also possible.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an embodying apparatus of the present invention in use.

FIG. 2 is a block diagram of the same.

[Explanation of symbols]

 1 cylinder 2 hose 3 storage furnace 4 pressure-electricity converter 5 digital display 6 pump 7 throttle valve 8 hose 9 electric wire 10 blowing pipe 11 melting furnace

Claims (4)

[Claims] 1. An inert gas is blown from a predetermined depth in the liquid, a change in the blowing pressure of the inert gas due to a change in the liquid surface height is detected, and the height of the measured liquid surface is measured based on the blow pressure. A liquid level height measuring method characterized by calculating. 2. The liquid level height measuring method according to claim 1, wherein the blowing pressure is converted into an electric output. 3. The liquid level height measuring method according to claim 1, wherein the inert gas is inert to the liquid to be measured. 4. An upper end of a gas pipe which is inserted into a liquid and blows out an inert gas from a lower end thereof is connected to an outlet of an inert gas cylinder by a gas supply hose, and a pressure is applied to the gas supply hose. A liquid level height measuring device characterized in that an electric conversion display means is connected.