SU121954A1 - Flow refractometer - Google Patents

Description

The known flow refractometers are based on the use of the effect of total internal reflection of light from the boundary of two media with different refractive indices. They have a complex optical system requiring the use of precise and expensive optical components.

The proposed refractometer is based on the principle of changing the refraction of a liquid lens formed by a transparent chamber, which makes it possible to substantially eliminate the disadvantages of sush, ec, refractometers. This refractometer has a simple optical system that does not require expensive, precise parts. The device is designed to measure changes in the refractive index of the flowing fluid, has a photoelectric receiver that perceives the light energy transmitted through the transparent refractometer chamber. The camera is made in the form of a hollow collecting lens. In addition, the refractometer is equipped with a second photoelectric receiver and a second hollow chamber, made in the form of a plane-parallel plate and located in series with the first chamber. These features of the invention provide changes in the amount of light energy supplied to the receiver, depending on the change in the refractive index of the flowing fluid, and eliminate the influence of the color and transparency of the fluid, as well as fluctuations in the light intensity of the source on the instrument readings.

The controlled fluid is passed through two series-connected chambers: / (see drawing), made in the form of a hollow collecting lens with transparent convex walls, which is the sensor of the measuring part of the device, and camera 2, prepared in the form of a plane-parallel plate with transparent walls, sensor of the compensating part of the refractometer. The light flux from the source 5 is directed through a condenser 4, a transparent lens /

№ 121954

and the diaphragm 5 on the photoelectric receiver 6. Since the refractive index changes accordingly with increasing or decreasing density of the flowing fluid, the focal distance of the lens / and the degree of illumination of the photoelectric receiver 6 automatically change. the brightness of the photoelectric receiver will decrease, while decreasing the density, on the contrary, will increase. At the lowest possible fluid density, the diaphragm 5 is set at the focus of the lens, /.

To eliminate the influence of the color and transparency of the liquid, as well as the fluctuations of the luminous intensity, the device has an optical compensation system that operates as follows. Light from source 3 through condenser 7. prism 8, transparent chamber 2 and optical wedge 9 is directed to photoelectric receiver W. Light passing through this system does not meet elements with variable refractive index in its path, as camera 2 has a flat -parallel walls- The amount of light that enters the photoelectric receiver 10 depends only on the color and transparency of the controlled liquid. The amount of light that enters the photoelectric receiver 6 of the measuring system will, in addition, depend on the refractive index of the liquid. Thus, the influence of color and transparency is excluded from the measurement indications, due to the non-identity of the light fluxes.

Through the resistances of the 11 - compensation n 12 - measuring systems, the currents caused by the action of light on the photoelectric receivers 10 and 6 pass. When the circuit is balanced, the voltage at the output terminals J3 and 14 is zero. If there is an imbalance as a result of a change in the concentration of the fluid at the terminals, the voltage is proportional to the magnitude of the change in concentration measured by a special measuring device connected to the terminals. The scaler instrument is calibrated against density reference samples directly in units of density of the fluid. Adjustment and adjustment of the refractometer are carried out with knobs / 5 and 16.

Subject invention

Claims (2)

1. Flow refractometer for measuring changes in the refractive index of a flowing fluid, having a photoelectric receiver that senses light energy transmitted through the transparent refractometer chamber, characterized in that, in order to change the amount of light energy supplied to the receiver depending on the change in refractive index of the flowing fluid The indicated camera is made in the form of a hollow collecting lens. 2. A flow refractometer according to claim 1, characterized in that. in order to eliminate the influence of the color and transparency of the liquid, as well as fluctuations of the source light intensity on the refractometer readings, the latter is equipped with a second photoelectric receiver and a second hollow chamber, made in the form of a plane-parallel plate and located in series with the first chamber.