JPH0643523U - Cargo level meter - Google Patents

Abstract

(57) [Summary] [Purpose] The wetted diaphragm can be reliably protected when cleaning the tank, and the liquid in the tank is hard to solidify on the pressure receiving surface side of the wetted diaphragm, so that pressure transmission to the wetted diaphragm is not possible. Good and improves measurement accuracy. [Structure] A flange 16 is fixed to a lower surface of a housing 13 having a semiconductor pressure sensor 18, a transmitter 20 and the like built therein.
A wetted diaphragm 17 is arranged at the center of the lower surface of the flange 16. Further, the upper end opening of the tubular body 40 is joined and fixed to the lower surface of the flange 16 to protect the liquid contact diaphragm 17. A plurality of gas vent openings 4 are provided at the upper edge of the cylinder 40.
1 is formed in the circumferential direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cargo level meter for measuring the liquid level of liquid such as crude oil stored in a closed tank.

[0002]

[Prior art]

 Conventionally, as a cargo level gauge (pressure type level gauge) of this type used to measure the level of liquid stored in a closed tank in a tanker, an oil refining plant, etc., for example, crude oil. Proposed. 4 and 5 show a conventional example of a cargo level meter. Briefly explaining it, 1 is a closed tank for storing crude oil 2, and this tank 1 is a tank bottom plate 3, deck 4, tank partition wall 5, etc. Since the crude oil 2 is combustible, an incombustible gas (inert gas) 6 is enclosed at a pressure (P0) slightly higher than atmospheric pressure. The cargo level meter 7 for measuring the liquid level height H of the crude oil 2 includes a pipe 8 arranged in the tank 1 along the partition wall 5, and two level detectors 9 and 10 attached above and below the pipe 8, respectively. And a temperature sensor 11 and the like.

As shown in FIG. 5, the high-voltage side level detector 9 located below includes a housing 13 formed of a tubular body connected and fixed to a lower end opening of the pipe 8 by a plurality of bolts 12, and a housing 13. A flange 16 which is in close contact with the lower surface of the flange via an O-ring 14 and is joined and fixed by a plurality of bolts 15, and a peripheral portion is fixed to the center of the lower surface of the flange 16 to form a pressure receiving portion for the crude oil 2. The liquid contact diaphragm 17, the semiconductor pressure sensor 18 disposed in the housing 13, and the displacement of the liquid contact diaphragm 17 enclosed between the liquid contact diaphragm 17 and the semiconductor pressure sensor 18 are transferred to the semiconductor pressure sensor 18. The transmission of the enclosed liquid 19 such as silicone oil to be transmitted and the displacement of the semiconductor pressure sensor 18 which is also disposed in the housing 13 by converting the displacement into an electric signal. A protective plate 21 is provided on the lower surface of the flange 16 for preventing damage and breakage of the wetted diaphragm 17 due to cleaning water during tank cleaning, and is fixed to the lower surface of the flange 16 by a plurality of bolts 23 via a spacer 22. There is. A large number of holes 24 are formed in the protective plate 21. The spacer 22 is provided only in the bolt fastening portion, and a gap G is formed between the adjacent bolts 23. Therefore, when the crude oil 2 is injected into the tank and the oil level rises, degassing is performed in this gap G, and when the wetted diaphragm 17 is immersed in the crude oil, this gap G and the hole 24 of the protective plate 21 are provided. Internal and external flow is performed through.

The low-voltage side level detector 10 located above is joined and fixed to a branch pipe 8 A provided at the upper end of the pipe 8 in the same configuration as the high-voltage side level detector 9.

In the figure, 25 is a printed wiring board forming the transmitter 20, 26 is potting for molding electronic components of the transmitter 20, 27 is a cable connecting the level detectors 9, 10 and the controller 28, 29 Is a tube for guiding the pressure of the noncombustible gas to the reference pressure side of the semiconductor pressure sensor 18, 30 is a connector, and 31 is a column for fixing the pipe 8.

In such a configuration, the high-pressure side level detector 9 installed below and the low-pressure side level detector 10 installed above detect the level pressures PL and PU at the installation positions and convert them into electric signals. The liquid level height H of the crude oil 2 can be measured by converting and transmitting the electric signal by the transmitting unit 20, and processing the electric signal by the processing circuit of the controller 28. That is, the level pressure PL in the high pressure side level detector 9 is expressed by the following equation: PL = P0 + .rho. (H-HL) ... (1). However: ρ is the density of the measurement target. The pressure PH in the low-pressure side level detector 10 is expressed 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) By substituting ρ of the equation (6) into the equation (3) or the equation (4), the liquid level height H at the liquid temperature can be calculated. The pressure PU when the low-pressure side level detector 10 is located above the liquid level height H is expressed by the following equation PU = P0 ... (7).

[0007]

[Problems to be solved by the device]

 In such a cargo level meter 7, as described above, the protection plate 21 is conventionally provided on the lower surface of the high-pressure side and low-pressure side level detectors 9 and 10 in order to prevent the wetted diaphragm 17 from being damaged by cleaning water when cleaning the tank. Although it is attached via the spacer 22, the flat plate causes the oil to solidify between the liquid contact diaphragm 17 and the protective plate 21 when the viscosity of the crude oil is high or the ambient temperature drops, and pressure transmission is not smooth. Therefore, there is a problem that the measurement accuracy is reduced.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to reliably protect a wetted diaphragm when cleaning a tank, and It is an object of the present invention to provide a cargo level meter that improves the measurement accuracy because the liquid in the tank is hard to solidify on the pressure receiving surface side of the diaphragm and the pressure transmission to the liquid contact diaphragm is good.

[0009]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides level detectors including a liquid contact diaphragm, a semiconductor pressure sensor, a transmitter, etc. above and below a tank for storing liquid, and these level detectors are used. In a cargo level meter that detects the level pressure of the liquid in the tank and measures the liquid level height from the signal, the liquid contact diaphragm connected to the lower part of the housing containing the semiconductor pressure sensor, transmitter, etc. A tubular body having both ends open surrounding the liquid contact diaphragm is joined and fixed to a flange having a diaphragm, and a plurality of degassing openings are circumferentially formed at the joining side opening edge of the tubular body.

[0010]

[Action]

 In the present invention, the cylindrical body joined and fixed to the flange protects the liquid contact diaphragm so that the cleaning water does not come into direct contact with the tank when cleaning. Also, since the bottom of the cylinder is missing, it is difficult for the liquid to solidify inside. The degassing opening of the cylinder allows the gas in the cylinder to escape to the outside when the liquid in the tank rises, and allows the liquid to flow in and out when the cylinder is immersed in the liquid.

[0011]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view of an essential part showing an embodiment of a cargo level meter according to the present invention, and FIG. 2 is a perspective view of a cylinder. In the figure, the same components as those in FIGS. 4 and 5 are designated by the same reference numerals, and the description thereof will be omitted. In these drawings, in this embodiment, the upper end opening of the tubular body 40 is joined by welding or the like to the lower surface of the flange 16 attached to the lower surface of the housing 13 in which the semiconductor pressure sensor 18, the transmitter 20 and the like are incorporated. It is fixed so that the liquid contact diaphragm 17 is protected from the cleaning water when cleaning the tank. The cylindrical body 40 is formed of a cylindrical body whose both ends are open, has an outer diameter D 2 which is larger than the outer diameter of the wetted diaphragm 17, and has a length L of about 2 / 3D to D. The extraction opening 41 is formed in the circumferential direction. In this case, as a matter of course, the opening 42 may be provided at the lower edge as shown in FIG. The other structure is similar to that of the conventional device shown in FIGS. 4 and 5. Reference numeral 43 is a screw hole into which a bolt 15 for fastening and fixing the flange 16 to the housing 13 is screwed.

In the cargo level meter having such a configuration, since the cylindrical body 40 is vertically provided below the flange 16, the liquid contact diaphragm 17 is washed with a cleaning liquid when cleaning the tank as compared with the conventional disc-shaped protective plate. It is possible to more reliably protect the wetted diaphragm 17 from damage and prevent damage to the wetted diaphragm 17 in advance. Further, when the crude oil is injected and the crude oil enters the cylinder 40, the internal air is released to the outside through the degassing opening 42, so that no air remains inside and the lower surface is opened. Because of this, the crude oil escapes well and does not accumulate inside and solidify. Further, as shown in FIG. 3, if an opening 42 is provided at the lower end edge of the tubular body 40, the viscous crude oil can be cut off easily.

In the present embodiment, the tubular body 40 is constituted by a cylindrical body, but the present invention is not limited to this, and a polygonal tubular body may be used.

[0014]

[Effect of device]

 As described above, in the cargo level meter according to the present invention, a flange equipped with a wetted diaphragm is fixedly joined to the lower surface of a housing containing a semiconductor pressure sensor, a transmitter, etc., and the wetted diaphragm is attached to the lower surface of this flange. Since a protective cylinder is laid vertically and a plurality of gas vent openings are formed at the joint-side opening edge of this cylinder, it is excellent in preventing damage to the wetted diaphragm by the cleaning liquid when cleaning the tank. In addition, even if the crude oil has a high viscosity or the ambient temperature drops, there is no risk of liquid accumulating in the cylinder and solidifying, and pressure can be transmitted smoothly to the wetted diaphragm, improving measurement accuracy. it can.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a cargo level meter according to the present invention.

FIG. 2 is a perspective view of a cylindrical body.

FIG. 3 is a perspective view showing another embodiment of the cylindrical body.

FIG. 4 is a configuration diagram showing a conventional example of a cargo level meter.

FIG. 5 is a sectional view of a level detector.

[Explanation of symbols]

 1 Tank 2 Crude Oil 6 Incombustible Gas 7 Cargo Level Meter 8 Pipe 9 High Pressure Level Detector 10 Low Pressure Level Detector 13 Housing 16 Flange 17 Wetted Diaphragm 18 Semiconductor Pressure Sensor 19 Filled Liquid 20 Transmitter 40 Cylindrical 41 Gas Out Opening

Claims (1)

[Scope of utility model registration request] 1. A top and bottom of a tank for storing a liquid,
A level detector consisting of a liquid contact diaphragm, a semiconductor pressure sensor, a transmitter, etc. is installed, and the level detector detects the level pressure of the liquid in the tank, and the signal is used to measure the liquid level height. In a level meter, a flange having the wetted diaphragm connected to a lower portion of a housing in which the semiconductor pressure sensor, the transmitter, etc. are built is joined and fixed to a cylinder body having both ends open, which surrounds the wetted diaphragm. A cargo level meter characterized in that a plurality of gas vent openings are formed in the circumferential direction at the joint-side opening edge of the body.