JPH11281457A - Level gage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a level gage which continuously measures even the level of nonconductive liquid such as oil. SOLUTION: A level gage is provided with a vertical shaft 3 which is inserted and rotatably supported in liquid stored in a container 2 along the gravity direction, a vane 4 which has a prescribed length along the axial direction in the vertical shaft 3 and is extended outward diametrically, a motor 5 which is attached to the vertical shaft 3 and drives to rotate the vertical shaft 3, and a level detecting means 6 which detects the liquid surface level from the load current of the motor 5 generated, when the vertical shaft 3 is rotated by the motor 5.

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 device for measuring a liquid level in a container.

[0002]

2. Description of the Related Art As a liquid level measuring device for measuring a liquid level in a container, there is an electric level transmitter used for a boiler.

[0003] The electric level transmitter measures the liquid level by supplying electricity to liquid (water) in a container.

[0004]

Since the electric level transmitter measures the level by applying a current to the liquid in the container, it can be used for non-conductive liquids such as oil. However, there is a problem that there is no practical level measuring device that cannot be used even in automatic control.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a liquid level measuring instrument capable of continuously measuring the level even of a non-conductive liquid such as oil.

[0006]

To achieve the above object, the present invention provides a vertical shaft rotatably supported by being inserted along the direction of gravity into a liquid contained in a container, A blade having a predetermined length along the axial direction and extending radially outward, a motor attached to the vertical shaft for driving the vertical shaft, and rotating the vertical shaft by the motor. And a liquid level detecting means for detecting a liquid level from a load current of the motor generated when the motor is driven.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a liquid level measuring instrument 1 includes a vertical shaft 3 inserted in a liquid contained in a container 2 along the direction of gravity and rotatably supported, and a vertical shaft 3. A blade 4 having a predetermined length along the axial direction and extending radially outward; a motor 5 attached to the vertical shaft 3 for driving the vertical shaft 3 to rotate; And a liquid level detecting means 6 for detecting the liquid level (the height of the liquid surface 17) from the load current of the motor 5 generated when the is rotated.

The container 2 is in the form of a tank for storing high-temperature oil. An inlet (not shown) for allowing oil to flow into the container 2 from outside, and the oil in the container 2 is supplied to the outside of the container 2. And an outflow port (not shown) for taking out the air. The liquid level in the container 2 rises when oil flows in from the inflow port, and falls when oil flows out from the outflow port.

The vertical shaft 3 extends vertically through the center of the ceiling 7 of the container 2 and extends outside the container 2 so as to be rotatable and vertically erected. A shaft seal 8 is provided between the ceiling 7 of the container 2 and the vertical shaft 3 so that high-temperature oil, which is a liquid in the container 2, does not leak out of the container 2.

The blade 4 is provided with a plurality of blade plates 9 formed of a vertically long rectangular plate long in the vertical direction below the vertical shaft 3 in a radial manner in plan view. Each wing plate 9 is made of a sufficiently strong and stable material such as metal so that it does not yield to the force received from the liquid when the vertical shaft 3 is rotated and can withstand high and low temperatures. Have been.

The motor 5 is disposed above the container 2 with the drive shaft 10 directed vertically downward, and the tip of the drive shaft 10 is coaxially and integrally connected to the upper end of the vertical shaft 3. I have. The motor 5 is connected to a battery 11 serving as a power supply via a power supply circuit 12.

The liquid level detecting means 6 is connected to the power supply circuit 12 and measures a load current of the motor 5 by a current measuring unit 13.
From the load current value measured by the current measuring unit 13
And a conversion unit 14 for obtaining the height of the reference numeral 7.

The current measuring section 13 and the converting section 14 are connected to each other via a wiring 15, and the load current value information measured by the current measuring section 13 is transmitted to the converting section 14 via the wiring 15. I have.

The converter 14 converts the input load current value information into liquid level information in consideration of the viscosity of the liquid to be measured.
The height of 7 is continuously output. Also,
The conversion section 14 has a display means 16 for displaying the liquid level, and the height of the liquid level 17 can be visually checked.

The relationship between the load current value and the liquid level is determined experimentally in advance by measuring the load current value while continuously increasing or decreasing the liquid in the tank. You may.

Next, the operation will be described.

When the container 2 is filled with oil, the blades 4 are rotated by being immersed in the oil to the upper end. The oil resistance and the hydraulic pressure are applied to the blades 4, and the motor 5 is also applied with a large resistance in a direction that hinders rotation.

For this reason, a large load current is generated in the power supply circuit 12 and the current measuring unit 13 of the liquid level detecting means 6
Detects this large load current. The detected load current value information is transmitted to the converter 14.

The conversion unit 14 converts the large load current value information transmitted from the current measurement unit 13 and displays the information on the display unit 16 as information in which the liquid level 17 is above the upper end of the blade 4.

In this state, when the liquid level of the oil in the container 2 gradually decreases and passes the position of the upper end of the blade 4, the upper end of the blade 4 projecting above the liquid level loses resistance due to the liquid. The resistance force applied to the motor 5 also gradually decreases.

For this reason, the load current in the power supply circuit 12 also decreases continuously and gradually. The current measuring unit 13 of the liquid level detecting means 6 continuously detects a gradually decreasing load current,
The load current value information is continuously transmitted to the converter 14.

The conversion section 14 converts the continuously transmitted load current value information into liquid level information in real time and displays it on the display means 16.

When the liquid level 17 in the container 2 drops below the blade 4, the blade 4 has no resistance due to the liquid.
The resistance applied to the motor 5 is also very small due to the air or gas in the container 2.

For this reason, the load current in the power supply circuit 12 is also minimized. The current measuring unit 13 of the liquid level detecting means 6 detects the minimum load current and converts the load current value information to the conversion unit 1.
4

The conversion section 14 converts the minimum load current value information transmitted from the current measurement section 13 and displays the information on the display means 16 as information in which the liquid level 17 is below the lower end of the blade 4.

As described above, the vertical shaft 3 is rotatably placed in the container 2.
And a vertically long blade 4, a motor 5 for rotating the vertical shaft 3 is mounted outside the vessel 2, and a liquid level detecting means 6 for detecting a liquid level from a load current of the motor 5 is provided to measure the liquid level. The liquid level measuring device 1 can be made to have a simple structure because the device 1 is configured. In particular, the liquid level can be continuously (real-time) accurately measured with high responsiveness from the upper end height to the lower end height of the blade 4. Can be obtained.

Further, since the change in the resistance of the liquid accompanying the change in the liquid level is utilized, the liquid level of any liquid can be measured regardless of the properties of the liquid such as the presence or absence of conductivity. It can be widely applied from low-temperature liquid to high-temperature liquid irrespective of liquid temperature and liquid pressure.

Then, the blade 4 is connected to a plurality of rectangular blade plates 9.
In particular, the liquid level and the resistance applied to the motor 5 can be made substantially proportional between the upper end and the lower end of the blade 4.

Since the vertical shaft 3 penetrates through the ceiling 7 of the container 2 and the shaft seal 8 is provided between the vertical shaft 3 and the ceiling 7 of the container 2, the container 2 is filled with oil. In other cases, oil can be prevented from being applied to the shaft seal 8, the hydraulic pressure acting on the shaft seal 8 can be minimized, and leakage of liquid can be prevented.

The current measuring section 13 of the liquid level detecting means 6
May obtain the load current value as digital information, and the conversion unit 14 may include an arithmetic device such as a CPU.

In this case, a thermometer (not shown) for measuring the liquid temperature is provided in the container 2, and when the conversion unit 14 calculates the liquid level, the calculation is made in consideration of the viscosity change of the oil due to the liquid temperature. Is also good.

Further, the motor 5 is not limited to the motor arranged above the container 2, but as shown in FIG.
The motor 5 may be arranged below the container 2, or the motor 5 may be arranged on the side of the container 2 as shown in FIG.

The difference between the liquid level measuring device 20 shown in FIG. 2 and the above liquid level measuring device 1 will be described.

The motor 5 of the liquid level measuring device 20 includes a drive shaft 10
Are arranged below the container 2 with the vertical direction upward, and the tip of the drive shaft 10 is coaxially and integrally connected to the lower end of the vertical shaft 21.

The shaft seal 8 is provided between the bottom 22 of the container 2 and the vertical shaft 21.

The blade 23 is composed of a plurality of vertically long rectangular plate-like blade plates 9. A plurality of blade plates 9 are attached to the upper part of the vertical shaft 21 in a radial manner in plan view.

By locating the motor 5 below the container 2 in this manner, the vertical axis 21 can be shortened, particularly when it is desired to measure the liquid level in the vicinity of the bottom 22 of the container 2. Can be made compact.

The difference between the liquid level measuring device 30 shown in FIG. 3 and the above liquid level measuring device 1 will be described.

The motor 31 of the liquid level measuring device 30 has a drive shaft 3
2 is arranged on the side of the container 2 with the horizontal facing. The tip of the drive shaft 32 extends through the side part 33 of the container 2 and extends into the container 2, and a first bevel gear 34 is coaxially provided at the tip of the drive shaft 32.

A shaft seal 8 is provided between the side portion 33 of the container 2 and the drive shaft 32 so as to prevent high-temperature oil, which is a liquid in the container 2, from leaking out of the container 2.

A vertical shaft 36 is vertically and rotatably provided in the container 2 via a bracket 35 serving as a support member. At the upper end of the vertical shaft 36, a second bevel gear 37 meshing with a first bevel gear 34 provided at the tip of the drive shaft 32 is provided. When the drive shaft 32 is rotated, the vertical shaft 36 is also rotated. It has become so.

The lower part of the vertical shaft 36 is provided with a blade 4 composed of a plurality of blade plates 9.

As described above, by positioning the motor 31 on the side of the container 2, the liquid level measuring device 30 can be easily installed even if the container has a complicated shape.

[0045]

As described above, according to the present invention, the level can be continuously measured even for a non-conductive liquid.

[Brief description of the drawings]

FIG. 1 is a side view of a liquid level measuring instrument according to a preferred embodiment of the present invention.

FIG. 2 is a side view of a liquid level measuring device according to another embodiment.

FIG. 3 is a side view of a liquid level measuring device according to another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 liquid level measuring device 2 container 3 vertical axis 4 blade 5 motor 6 liquid level detecting means 17 liquid level 20 liquid level measuring device 21 vertical axis 23 blade 30 liquid level measuring device 31 motor 36 vertical axis

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[Procedure amendment]

[Submission date] July 3, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

The container 2 is in the form of a tank for storing high-temperature oil, for example. An inlet (not shown) for allowing oil to flow into the container 2 from the outside, and the oil in the container 2 is stored in the container 2. And an outlet (not shown) for outflow. The liquid level in the container 2 rises when oil flows in from the inflow port, and falls when oil flows out from the outflow port.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

The vertical shaft 3 extends vertically through the center of the ceiling 7 of the container 2 and extends outside the container 2 so as to be rotatable and vertically erected. A shaft seal 8 is provided between the ceiling 7 of the container 2 and the vertical shaft 3 so that the liquid in the container 2 does not leak out of the container 2.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The blade 4 is provided with a plurality of blade plates 9 formed of a vertically long rectangular plate long in the vertical direction below the vertical shaft 3 in a radial manner in plan view. Each slat 9 so as not succumb to the force received from the liquid when the Tatejiku 3 is rotated, also used
It is made of a sufficiently strong and stable material such as metal to withstand high or low temperature depending on the purpose of use .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

The motor 5 is disposed above the container 2 with the drive shaft 10 directed vertically downward, and the tip of the drive shaft 10 is coaxially and integrally connected to the upper end of the vertical shaft 3. I have. Further, the motor 5, 1 1 (FIG power battery used
However, if the power supply is stable, a battery
Need not be connected ) via the power supply circuit 12.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

When the container 2 is filled with the liquid , the blade 4 is rotated while being immersed in the liquid to the upper end. The resistance and liquid pressure of the liquid are applied to the blades 4, and the motor 5 is also applied with a large resistance in a direction that hinders rotation.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

In this state, when the liquid level in the container 2 gradually decreases and passes the upper end of the blade 4, the upper end of the blade 4 which rises above the liquid level has no resistance due to liquid, and the motor 5 The resistance applied to the body gradually decreases.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

When the liquid level 17 in the container 2 drops below the blade 4, the blade 4 has no resistance due to the liquid.
Resistance force applied to the motor 5 also becomes very thing Umate little in those with air or gas in the container 2.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

Further, since the vertical shaft 3 is made to penetrate the ceiling 7 of the container 2 and the shaft seal 8 is provided between the vertical shaft 3 and the ceiling 7 of the container 2, the liquid is filled in the container 2. In other cases, the liquid can be prevented from being applied to the shaft seal 8, the hydraulic pressure acting on the shaft seal 8 can be minimized, and the leakage of the liquid can be prevented.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

In this case, a thermometer (not shown) for measuring the liquid temperature is provided in the container 2, and when the conversion unit 14 calculates the liquid level, the calculation is made in consideration of the viscosity change of the liquid due to the liquid temperature. Is also good.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

A shaft seal 8 is provided between the side portion 33 of the container 2 and the drive shaft 32 so as to prevent the liquid in the container 2 from leaking out of the container 2.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Change

[Correction contents]

[0045]

In summary, according to the present invention, the level can be continuously measured even for a non-conductive liquid.

Claims (1)

[Claims] 1. A vertical shaft rotatably supported by being inserted along the direction of gravity into a liquid contained in a container, having a predetermined length along the axial direction of the vertical shaft, and A blade extending radially outward, a motor attached to the vertical shaft for rotating the vertical shaft, and a liquid level obtained from a load current of the motor generated when the vertical shaft is rotationally driven by the motor. A liquid level measuring device comprising a liquid level detecting means for detecting.