JPH0415406B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid level meter for measuring the liquid level of liquid metal, and particularly for measuring the liquid level in a high-temperature liquid metal container of a fast breeder reactor. This article relates to a float-type laser level meter for measurement.

[Conventional technology]

Generally, in fast breeder reactors, it is necessary to constantly measure the coolant level of high-temperature liquid metal, and various level meters are used for this purpose. Accurate distance meters using laser technology are already available.
Although it has become common and commercialized, a laser level meter for use in containers of high-temperature liquid metal used as a coolant in fast breeder reactors has not yet been developed.

[Problem that the invention seeks to solve]

However, in order to use laser technology for level meters in high-temperature liquid metal containers in fast breeder reactors, if a laser beam is irradiated directly onto a liquid that is likely to cause reflections, it will cause diffuse reflections due to disturbances in the liquid surface. In some cases, it may be impossible to receive the reflected light, and the glass surface of the laser beam emitting/receiving device may It has problems such as clouding and adversely affecting measurement accuracy.

The present invention is intended to solve the above problems,
A float-type laser level that can measure the liquid level with high precision by preventing diffused reflection due to turbulence on the liquid level and clouding of the glass surface of the laser beam emitter and receiver due to vapor generated from high-temperature liquid metal. The purpose is to provide a

[Means for solving problems]

For this purpose, the float type laser level meter of the present invention
A guide sleeve is formed with a gas vent hole at the top and a hole for liquid metal inflow and outflow at the bottom, and is placed so that it is partially submerged in the liquid metal. A float that has a small outer diameter, has a laser beam reflecting surface consisting of a spherical head, and is formed so that the center of gravity is below the center of buoyancy, and a float that is connected to the upper part of the guide sleeve and placed inside the guide sleeve. It is equipped with piping for inflowing gas and a laser beam emitting receiver installed at the upper end of the guide sleeve, and while the liquid metal vapor in the guide sleeve is removed by the gas flowing in from the piping, the laser beam emitting receiver is It is characterized by measuring the level of liquid metal by reflecting the emitted laser light on the reflective surface of the float and receiving it.

[Effect]

The float-type laser level meter of the present invention floats a float having a spherical reflective surface in a guide sleeve whose lower end is inserted below the liquid surface from outside the liquid metal container, and introduces gas into the guide sleeve to measure the liquid metal. The liquid level can be detected by emitting laser light from a laser transmitter/receiver provided on the upper part of the guide sleeve while discharging steam and receiving the reflected light from the reflective surface of the float.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of an embodiment of a float type laser level meter according to the present invention, and FIG. 2 is a diagram showing a guide sleeve portion. In the figure, 1 is a float, 2 is a guide sleeve, 3 is a container, 4 is a liquid metal level, 5 is a gas vent hole, 6 is an inflow and outflow hole, 7 is a laser hole transmitter/receiver, 8 is a door valve, and 9 is a conversion 10 is an indicator, 11 is piping, 12 is a valve, 13 is a laser beam, XX is the central axis of the guide sleeve, and Y-Y is the central axis of the float.

In FIG. 1, the guide sleeve 2 is airtightly attached to the container 3, and a gas vent hole 5 and a hole 6 for liquid metal inflow and outflow are provided above and below the liquid level 4, respectively. There is no difference in liquid metal level. Float 1
moves up and down as the liquid level changes, with a very small distance between its side surface and the guide sleeve, and reflects the laser beam 13 on the reflective surface of its head. The laser beam emitting/receiving device 7 is attached to the head of the guide sleeve 2 via the door valve 8 so as to irradiate the float 1 with a laser beam parallel to its central axis X-X.
The door valve 8 can be closed as necessary when laser light is not being emitted or received. Processing of the laser beam emitted and received signal is performed by a converter 9, and an indicator 10
to indicate the level. Further, between the container 3 and the door valve 8, a pipe 11 is hermetically connected to the guide sleeve 2 via a valve 12, and is opened to the guide sleeve 2 to introduce gas into the interior.

In FIG. 2, the head reflecting surface of the float 1 has a spherical shape, as will be described later, and even if the liquid level 4 fluctuates and the spherical float 1 tilts, the shape of the exposed part from the liquid level 4 will not change. never changes. Therefore, the reflecting surface is always maintained perpendicular to the irradiated laser beam 13, and the reflected light is reflected toward the laser beam emitting/receiving device. Furthermore, since the inner diameter of the guide sleeve and the outer diameter of the float are almost the same, evaporation of the high-temperature liquid metal can be reduced. By doing so, it is possible to prevent the vapor from rising and to prevent the glass of the laser beam emitting/receiving device 7 from fogging up.

In this way, the laser beam 13 can be irradiated from the laser beam emitter/receiver 7 to the float 1 without being attenuated by the glass surface of the laser beam emitter/receiver 7, and a sufficient amount of reflected light can be received from the float 1. . This received signal is passed through a converter 9 to an indicator 10 to indicate the level of the liquid surface 4 in consideration of the height of the float 1 from the liquid surface.

FIG. 3 is a diagram showing details of the float of the present invention, and the second
The same numbers as in the figure indicate the same content. In addition, 21 in the figure
is an upright float, 21A is an inclined float 21, θ
is the inclination angle of the float 21A, AB is the stuttering surface of the float 21, CD is the moving position of the AB surface on the float 21A,
Y-Y is the center axis of float 1, O is the center axis Y of float 1
This is the intersection of −Y and the stuttering surface AB.

In the figure, the float 21 has a spherical head whose center is on the central axis Y-Y that reflects laser light at the upper end of a cylindrical body whose cross section is circular or a regular polygon with an even number of sides. The center of gravity is located below the center of buoyancy, resulting in a stable structure. When a float is floating in liquid metal, the weight of the float in the gas and the weight of the liquid displaced by the float are equal. Since the weight of the float does not change, the volume of the float in the liquid does not change even if the float tilts. Therefore, the float 21, which is made symmetrically about the central axis Y-Y, is tilted by an angle θ and 2
When the condition is 1A and the stuttering surface AB moves to the position CD, the stuttering surface AB and CD intersect at a line passing through point O, and the part surrounded by AOC submerged in the liquid and the part outside the liquid are separated. The parts surrounded by BOD are equal. That is, when the float 21 inclines, the water surface changes around point O.

The float 21 has a spherical head whose center is on the central axis Y-Y, and the outer diameter of the float 21 is formed slightly smaller than the inner diameter of the guide sleeve 2, so that the float 21 is connected to the guide sleeve 2. Since the center axis of the guide sleeve 2 and the center axis of the float 21 are not far apart from each other, the float 21 is tilted due to fluctuations in the liquid level. Even if the guiding sleeve is configured to maintain a reflective surface perpendicular to the laser light from the laser transmitter at the upper end of the guide sleeve, the reflected light can be received by a laser receiver to detect the level of the liquid metal.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by providing the guide sleeve in the high temperature metal liquid container, fluctuations in the liquid level in the guide sleeve can be prevented, and changes in the liquid metal level in the guide sleeve can be prevented. By equipping the guide sleeve with a float that moves up and down in response to the laser beam and has a reflective surface that is always perpendicular to the laser beam, the liquid level in the guide sleeve is reduced and the rise of high-temperature steam is reduced, and the upper part of the guide sleeve By sending gas for high-temperature steam exhaust from the float, the laser light emitted from the laser emitter/receiver on the upper part of the guide sleeve is reflected back to the laser emitter/receiver by the float's spherical surface while improving the laser light reflection efficiency of the float. , the stable and accurate liquid level can be indicated by an indicator via a converter.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the overall configuration of an embodiment of a float type laser level meter according to the present invention, FIG. 2 is a diagram showing a guide sleeve portion, and FIG. 3 is a diagram showing details of the float of the present invention. 1... Float, 2... Guide sleeve, 3... Container, 4... Liquid level, 5... Gas vent hole, 6... Outflow/inflow hole, 7... Laser light emitting/receiving device, 8... Door valve, 9...Converter, 10...Indicator, 11...
Piping, 12... Valve, 13... Laser light, 21
...An upright float.

Claims (1)

[Claims] 1. A guide sleeve that has a gas vent hole at the top and a hole for liquid metal inflow and outflow at the bottom, and is arranged so that it is partially submerged in the liquid metal. A float that has a small outer diameter, has a laser light reflecting surface consisting of a spherical head, and is formed so that the center of gravity is below the center of buoyancy, and a float that is connected to the upper part of the guide sleeve and has a laser light reflecting surface consisting of a spherical head. It is equipped with piping for allowing gas to flow into the guide sleeve, and a laser beam emitting/receiving device provided at the upper end of the guide sleeve. A float-type laser level meter is characterized in that it measures the level of liquid metal by reflecting and receiving laser light emitted from the reflecting surface of a float.