Discrete optical transmitter

 

(57) Abstract:

Usage: the invention can be used for level measurement in both transparent and opaque media. Discrete optical transmitter includes vertical racks, which are the primary and secondary optical fibers respectively connected to the source of light radiation, and the radiation detector. The transmitter is equipped with a prism whose base is installed at an angle of 0 to 15° to the axis of the rack, and the side faces are cylindrical protrusions with spherical ends, which is tightly fitted adjusting sleeve placed in them by the free ends of the optical fibers. 3 Il.

The invention relates to discrete optical sensors and can be used for level measurement in both transparent and opaque media.

Known discrete optical transmitter, containing situated on the height of the controlled level converters, made in the form of prisms, the main line which passes the luminous flux, being immersed in the liquid, and recognizes it when it is out of fluid, a source of light radiation, light radiation receivers, fiber optic cables, one of the to the e auxiliary faces of the prisms with the radiation receivers.

The disadvantages of this device are low-precision measurements, a narrow range of measurement and application, as well as the bulkiness sensitive and the light guide elements, restricting the use of the sensor for closed tanks, especially when the excessive pressure in them.

The closest in technical essence to the invention is a discrete optical transmitter, containing situated at an altitude of controlled capacity racks set n of level converters connected via optical fibers one to the source of light radiation, and the other to the level indicator. At this level transducers made in the form of hook-shaped exposed parts of siteprovides in the horizontal plane with the number of scrap turns more than one, and the sensor is put screens mounted between the exposed areas of the neighboring siteprovides and between the exposed areas of each loop. The distance between adjacent transducers level is selected depending on the required number of discreteness level. The level indicator comprises a receiver of light radiation, connected to the processing unit of the signal, whose output is connected to a recording device.

Low sensitivity of the sensor is due to the fact that in case of violation of the conditions of total internal reflection at the boundary of the glass-liquid only part of the light penetrates into the liquid, resulting in only a decrease in incident on the receiver of the light flux, and not the complete disappearance of the light flux output from the optical fiber.

The range of application of the known sensor is determined by the type of fiber used as a Converter (for example, quartz, polymer, etc. and a certain ratio of its refractive index and the refractive index of the liquid. Only for a narrow range defined by the specified ratio of the refractive indices of the fiber in the liquid, can be used a known transmitter.

The complexity of the structural scheme of the sensor is that it contains the receiver light radiation, related handling block signal and connected to the block recording device.

The purpose of the invention is the improvement of sensitivity, extending the scope of application and simplification of the structural schema.

This objective is achieved in that in a discrete optical level additional fibers connected respectively to the source of light radiation to the receiver. The free ends of the optical fibers are located at the lateral faces of a prism having a cylindrical protrusions with spherical ends, which is tightly fitted adjusting sleeve. The base of the prism is set at an angle of 0-15aboutto the axis of the racks.

Increasing the sensitivity of the sensor is achieved through the execution of level converters in the form of a prism, is supplied mounted on the prism faces and provides for the creation of a parallel flux of light rays incident on the main face of the prism. Consequently, when the main contact face of the prism with the liquid, the refractive index of which is even slightly different from the refractive index of the gas environment, is a violation of total internal reflection in the prism and the changing direction of the output light flux that is incident on the input end of the optical fiber connected to the scoreboard indicator. Thus in contact with the liquid is abruptly changed (reduced to zero) of the light flux in the light guide associated with scoreboard display.

These signs provide in the absence of fluid reflection and the origin through the fiber is the tourism. Therefore, the invention provides a greater range of change of the output luminous flux in comparison with the prototype, and thus greater sensitivity.

Extending the scope of application of the sensor is due to the fact that the base of the prism is set at an angle of 0-15aboutto the axis of the rack that provides runoff from the base of the prism liquids with a wide range of viscosities without the formation of droplets on it, and also due to the fact that it can be used for level measurement of all liquids with a refractive index higher than the refractive index of the gas environment. The use of densely planted alignment bushings ensures constant conditions for the passage of light between the ends of the cylindrical projections of prisms, regardless of the parameters of the liquid in the tank.

Simplification of the structural scheme is achieved by the fact that due to the large range of variation of the output light flux to be transmitted to the scoreboard display, possible visual observation of the indications on the display indication, and therefore not necessarily using block processing signal to a recording device. This circumstance is achieved by the fact that due to the use of tsilindricheskogo fiber, connected to the sources of light radiation and incoming end of the light wave conductors connected to the scoreboard display, which provides the transmission of the light flux in the light with minimal losses, i.e., the larger luminous flux in comparison with the prototype with the same power source of the light beam.

In Fig.1 shows a General diagram of the device of Fig.2 is a view along arrow a in Fig.1; Fig.3 is a diagram of the passage of luminous flux in the transducer level.

Discrete optical transmitter includes spaced along the height of the controlled tank 1 rack 2 running n converters, level 3, is connected through the optical fibers 4 on one side to the source 5 light radiation, and the other to the pointer 6 levels, each Converter 3 is made in the form of a prism 7, a base 8 which is planar and is angled =0-15aboutto the axis of the uprights 2 (see Fig.2) and the side faces 9 and 10 are cylindrical protrusions 11 and 12 with a spherical end faces 13 and 14, into which is tightly fitted sleeves 15 and 16 placed in them by the free ends of the optical fibers 4. On the display 6 fixed output ends of the optical fibers 17 4 attached to the side edges 9 of the prism 7. The weekend ends 17 MAG.

The transmitter operates as follows.

When the vessel is empty 1 base 8 converters 3 are in the gas medium and the prism 7 is practically the conditions of total internal reflection of the beam of rays coming from the source 5 to the light rays through a spherical end faces 13 and 14 and the cylindrical protrusions 11 and 12. Thus the flux from the source 3 enters the light guide 4 on the scoreboard display 6, which are illuminated output ends of the optical fibers 4. To ensure total internal reflection on the main faces of the prism 7 other faces 9 and 10, it is set at an angle determined by the refractive index of the prism 7 and the refractive index of the gas environment in the tank 1.

Because the ends of the optical fibers 3 inserted in the focus of the spherical ends 13 and 14 of the cylindrical protrusions 11 and 12, diverging beam of light rays from the end face of the optical fiber 4 is connected to the radiation source 5 is converted into a parallel beam of light rays which are reflected from the main faces that come through the cylindrical protrusion 12 and the spherical end 14 in the form of a converging beam of light rays on the end face 17 of the light guide 4, is installed in the indicator 6. As the filling of the tank 1 convert the reflection at the boundary of the prism-liquid. Violation of these conditions leads to the fact that the luminous flux penetrates into all the liquid and is incident on the end face of the light guide 4, is connected to a level indicator 6, and the output ends 17 cease to glow. Thus on the level indicator 6 glow only output ends of the optical fibers 17 3 associated with transmitters, level 3, located in the gas environment, and not light ends 17 of the optical fibers 3 which are connected with level converters 3, immersed in the liquid.

The design of the level meter provides the greatest amplitude change of the output signal, which allows the use of visual observation of the change of sensor readings on the dipstick. Developed optical system provides a variation of the output signal from the maximum to the zero level in the absence and presence of contact with the transducer level. The use of optical fibers allows to transmit the optical signal over a distance of several tens of meters and measure the level in the tank without the use of photodetectors.

Along with the above advantages of the proposed device provides almost complete explosion in the measurement of level in tanks with oruchinga tanks, for example, automobiles, including liquefied gas.

In addition, the proposed device has a higher reliability compared to the prototype by simplifying design concept, as well as lower power requirement.

DISCRETE OPTICAL TRANSMITTER, comprising vertical uprights, one of which is fixed evenly along the height of the optical fibers, a source of light radiation, associated with one end of each optical fiber, and a radiation receiver, characterized in that it is equipped with prisms and more optical fibers, one end of which is connected with the radiation detector in optical fibers mounted on the other vertical rack, side faces of each prism is made with a cylindrical protrusions with spherical ends, covered adjusting sleeves, each of which is located on one free end of the respective additional and primary fibers and the base of the prism is set at an angle 0 to 15oto the axis of the vertical posts.

 

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