JP2733726B2 - Pressure level gauge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure type liquid for measuring a liquid level, for example, a crude oil, which is stored in a closed tank.
It relates to a face gauge .

[0002]

2. Description of the Related Art Various types of pressure-type liquid level gauges (cargo level meters) used for measuring the liquid level in a closed tank in a tanker, a petroleum refining plant, etc. have been proposed. ing. FIG. 3 and FIG. 4 show a conventional example of a cargo level meter. Briefly explaining the example, reference numeral 1 denotes a closed tank for storing crude oil 2 and this tank 1
Is composed of a tank bottom plate 3, a deck 4, a tank bulkhead 5, etc.
Since crude oil is flammable, a nonflammable gas (inert gas) 6 is sealed at a pressure (P0) slightly higher than the atmospheric pressure. A cargo level meter 7 for measuring the liquid level H of the crude oil 2 includes a pipe 8 disposed in the tank 1 along the partition wall 5, and two level detectors 9, 10 attached above and below the pipe 8, respectively. And a temperature sensor 11 and the like. The level detector 9 (similarly for 10) has one side of crude oil 2
A liquid contact diaphragm 12 forming a pressure receiving portion, a semiconductor pressure sensor 13, and a sealed liquid 1 such as silicon oil for transmitting a displacement of the liquid contact diaphragm 12 to the semiconductor pressure sensor 13.
4, an electric device unit 15 that converts the displacement of the semiconductor pressure sensor 13 into an electric signal and transmits the electric signal, a pressure sensor 16 that detects the pressure of the inert gas 6, and the like.

In such a configuration, the level pressures PL and PU at the installation positions are detected by a high-pressure level detector 9 installed below and a low-level level detector 10 installed above and converted into electric signals. Electrical equipment part 1
5, and the electric signal is processed by a processing circuit, whereby the liquid level H can be measured. That is, the level pressure PL in the high-pressure side level detector 9
Is represented by the following equation: PL = P0 + ρ (H−HL) (1) Where: ρ is the density of the object to be measured. The pressure PH in the low-pressure side level detector 10 is represented by the following equation: PU = P0 + ρ (H−HU) (2) From the above equation (1), H = {(PL−P0) / ρ} + HL (3) From the above equation (2), H = {(PU−P0) / ρ} + HU (4) From Equation (1) -Equation (2), PL-PU = ρ (HU−HL) (5) ∴ρ = (PL−PU) / (HU−HL) (6) HU, HL is uniquely determined when the cargo level meter is installed and is known. Therefore, by substituting ρ in equation (6) into equation (3) or (4), the pressure at the liquid temperature,
That is, the liquid level height H can be calculated. The pressure PU when the low-pressure level detector 10 is located above the liquid level H is expressed by the following equation: PU = P0 (7)

[0004]

However, in such a conventional cargo level meter, two levels, a high pressure side and a low pressure side, are used to measure the level pressures PU and PL of the crude oil 2 and the pressure P0 of the inert gas 6. Since the detectors 9 and 10 and the pressure sensor 16 are required, there is a problem that the number of parts increases and the cost increases.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to eliminate the need to measure the inert gas pressure, to measure the liquid level, and to measure the liquid level. Another object of the present invention is to provide a pressure-type liquid level gauge which achieves simplification and cost reduction and prevents the influence of droplets.

[0006]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention is to provide a closed tank storing liquid.
Pipe that is vertically installed and the lower end extends to near the bottom of the tank
And the non-flammable gas at the top of the tank
A pressure guiding tube for guiding the pressure of the layer to the semiconductor pressure sensor;
And a second pressure measuring unit, wherein the first pressure measuring unit is
It is provided at the lower end of the pressure guiding tube, and the liquid in the tank is provided on one side.
Pressure and the other side is filled with die
A diaphragm, a pressure-receiving part on the side of the sealed liquid and a non-combustible gas.
A semiconductor pressure sensor having a pressure receiving part on the pressure guiding tube side for guiding pressure
And convert the displacement of this semiconductor pressure sensor into an electrical signal
It consists of a level detector equipped with an electrical device part for transmitting,
The second pressure measuring unit is provided near the liquid level of the pipe.
A level detector having the same configuration as the level detector of the first pressure measuring section.
It is characterized by comprising a detector. The second invention is as described above.
In the first invention, the pressure guide tube is provided at an upper end opening.
A cylindrical protective tube and an anti-blocking plate for protecting the protective tube
The provided, the closure preventing plate, the lower surface is tapered in U-shaped
It is characterized by being inclined and arranged such that one end opening faces the pipe , and the height of the one end opening is set lower than the height of the opening on the side opposite to the pipe .

[0007]

According to the first aspect of the invention, the pressure guiding tube connects the inert gas space in the tank to the counter pressure receiving side of the semiconductor pressure sensor, and guides the inert gas pressure to the reference pressure side of the semiconductor pressure sensor. As a result, the sensor measures the level pressure based on the inert gas pressure, thereby eliminating the need for a pressure sensor for measuring the inert gas pressure and the processing for calculating the inert gas pressure and the liquid pressure. In the second invention, the protection tube and the blockage prevention plate prevent liquid droplets in the tank from adhering to the upper end opening of the pressure guiding tube and solidifying to close the opening. Further, the blockage prevention plate is formed in a special shape which is U-shaped and is tapered and inclined, and the penetration of the droplets is reduced depending on the direction thereof, and the attached droplets are easily dropped as droplets.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. FIG. 1 shows a pressure type liquid level gauge according to the present invention.
FIG. 2 is a schematic cross-sectional view showing an embodiment applied to a goniometer .
FIG. 3 is a perspective view of a protection tube and a blockage prevention plate. In addition, FIG.
4 and the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. In these figures, in this embodiment, level detectors 9, 10 are provided at the upper and lower ends of a pipe 8.
And the gas pressure P0 of the inert gas 6 in the tank 1 is set to the semiconductor pressure sensor 13 of each of the level detectors 9 and 10.
A pressure guiding tube 20 for guiding to the reference pressure side is disposed inside the pipe 8, and a cylindrical protective tube 22 and a U-shaped blocking prevention plate 23 are provided at an upper end opening 21 of the pressure guiding tube 20.
The configuration is such that the crude oil 2 is prevented from jumping up and adhering to the upper end opening 21 and solidifying.

A cylindrical opening 24 is formed at an appropriate position on the deck 4 constituting the tank 1.
Is hermetically covered by a connection box 25. The upper end of the pipe 8 is joined and fixed to the lower surface of the bottom plate 25A of the connection box 25. The upper end of the pressure guiding tube 20 protruding into the terminal box 25 from the upper end opening of the pipe 8 is bent into a hook shape, a U-shape, or the like, and the leading end opening 21 is formed in an insertion hole formed in the bottom plate 25A. , And faces the inert gas layer in the tank 1. The protection tube 22 is fixed to the lower surface of the bottom plate 25A by welding coaxially with the insertion hole. The blocking prevention plate 23 is formed in a U-shape as shown in FIG. 2 by bending a metal plate, molding a resin, or the like, and has an opening height and width from one end opening 23A to the other end opening 23B. It is formed to be tapered so as to gradually decrease,
Fixed portions 23a and 23b provided on both side ends are provided on the lower surface of the bottom plate 25A at the opening ends 23 having a small opening height and width.
B is fixed so as to be directed toward the pipe 8.

Since the combustion gas of heavy oil is usually used as the inert gas 6, the inert gas 6 contains a small amount (about 0.3%) of sulfur dioxide (SO2), which has a bad influence on the electronic parts of the electric equipment unit 15. There is a fear. Therefore, a desiccator 26 is installed in the middle of the impulse line 20 so that the SO ₂
Has been removed. Reference numeral 27 denotes an electric signal line, which is connected to a terminal (not shown) provided in the terminal box 25.

Thus, in the cargo level meter having such a configuration, the inert gas pressure P0 in the tank 1 is guided to the reference pressure side of the semiconductor pressure sensor 13 by the pressure guiding tube 20, and the inside of the tank 1 is determined based on the gas pressure P0. Crude oil 2
Since the level pressure P is measured, the calculation formulas (3), (4), (5), and (6) in the above-described conventional apparatus are used.
Becomes as shown in the following equations (3) ′, (4) ′, (5) ′, and (6) ′. H = (ΔPL / ρ) + HL (3) ′ H = (ΔPU / ρ) + HU (4) ′ ΔPL−ΔPU = ρ (HU−HL) (5) ′ .rho. = (. DELTA.PL-.DELTA.PU) / (HU-HL) (6) '.DELTA.PL and .DELTA.PU are pressures measured by the pressure sensors 9 and 10. FIG. By substituting the above (6) ′ into the above equation (3) ′ or the equation (4) ′, the liquid level height H can be obtained. As a result, the pressure sensor 16 (see FIG. 3) for measuring the inert gas pressure P0, which is conventionally required, is unnecessary.

When the oil 2 splashes or residual oil adheres to the upper end opening 21 of the impulse line 20 and solidifies due to the rocking of the tanker, the impulse line 20 is closed and the inert gas pressure in the impulse line 20 is fixed and measured. Although an error occurs, in the present invention, the pressure guiding tube 20 is
Since the upper end opening 21 is protected, splashes and the like do not directly adhere to the opening 21 and splashes and the like that adhere to the blocking prevention plate 23 themselves are formed in a U-shaped tapered shape by the blocking prevention plate 23. Therefore, there is no danger that it will flow down and accumulate on the blockage prevention plate 23. In this case, the upper end opening 2 of the pressure guiding tube 20
1 is usually located close to the pipe 8, and if the blocking prevention plate 23 is arranged with the opening 23B having a small height and width opposed to the pipe 8, the splash which bounces on the pipe 8 Can be reduced into the inside of the blockage prevention plate 23, and the upper end opening 21
Can be protected from splashing.

[0013]

As described above, the pressure type according to the present invention is
The liquid level gauge is configured to guide the noncombustible gas in the tank to the reference pressure side of the semiconductor pressure sensor by the pressure guiding tube, detect the liquid pressure based on the noncombustible gas pressure, and measure the liquid level. Further, a pressure sensor for detecting the pressure of the non-combustible gas is not required, and the simplification and low cost of the liquid level gauge itself can be realized. Further, in the present invention, the upper end opening of the pressure guiding tube is protected by the cylindrical protection tube and the U-shaped curved tapered blocking prevention plate, so that the liquid in the tank adheres to the opening and solidifies. As a result, it is possible to prevent the pressure guiding tube from being closed, and it is possible to quickly drop the droplets adhering to the prevention plate itself, and to prevent stagnation and solidification.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a cargo level meter according to the present invention.

FIG. 2 is a perspective view of a protection tube and a blockage prevention plate.

FIG. 3 is a configuration diagram showing a conventional example of a cargo level meter.

FIG. 4 is a cross-sectional view of the level detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 2 Crude oil 6 Noncombustible gas 7 Cargo level meter 8 Pipe 9 High pressure side level detector 10 Low pressure side level detector 12 Diaphragm 13 Semiconductor pressure sensor 14 Filled liquid 15 Electric device part 16 Pressure sensor 20 Pressure guide tube 21 Upper end opening 22 Protection tube 23 Blockage prevention plate

Claims (2)

(57) [Claims] Claims: 1. A suspended tank in which a liquid is stored.
A pipe whose lower end extends close to the bottom of the tank;
It is inserted into this pipe and the non-combustible gas layer
A pressure guiding tube for guiding pressure to the semiconductor pressure sensor;
And a second pressure measuring unit, wherein the first pressure measuring unit is provided at a lower end of the pressure guiding tube,
One side receives the pressure of the liquid in the tank, and the other side encloses
The diaphragm in which the liquid is sealed and the receiving
Pressure section and a pressure receiving section on the pressure guiding tube side for guiding the pressure of the noncombustible gas.
Semiconductor pressure sensor, and a variation of the semiconductor pressure sensor.
Electrical equipment that converts the position into an electrical signal and transmits it
A level detector, wherein the second pressure measuring unit is provided near the liquid level of the pipe.
A level detector having the same configuration as the level detector of the first pressure measuring section.
A pressure type liquid level gauge comprising a detector . 2. The pressure type liquid level gauge according to claim 1, wherein a cylindrical protective tube provided at an upper end opening of the pressure guiding tube is provided.
And a closure preventing plate for protecting the protective tube, the closure preventing plate, the lower surface is inclined in a tapered shape with a U-shaped, one end opening
A pressure-type liquid level gauge, wherein the pressure-type liquid level gauge is arranged so as to face the pipe , and the height of the one end opening is set lower than the height of the opening on the side opposite to the pipe.