SU890208A1 - Device for measuring humidity of sheet moving materials - Google Patents

Description

I

The invention relates to a measurement technique and is intended to measure the moisture content of sheet moving materials in a wide range of moisture contents.

A device for measuring the moisture of moving materials is known based on the conductometric method. It contains a double-sided roller sensor which presses against the tape of the material due to the weight of the upper roller, which is raised by the hinge. The resistance of the sensor with the material is measured at a constant current 1.

The closest to the present invention is a moisture meter containing a sensor representing a system of three roller sensors electrically isolated from each other, located on the same shaft and pressing with constant pressure to the surface of the material on one side with a special pressure device. On the other side of the material, there is a rotating shaft, which is necessary to create the required pressure to press the roller sensors to the material being monitored.

The resistance of a conductometric sensor with a material is measured at a direct current by a conversion having a measuring instrument calibrated in percent of the humidity of the material being monitored 2.

A disadvantage of the known device is the narrow range of measuring the moisture content of materials, limited by its maximum hygroscopic value. The purpose of the invention is to expand the measurement range in the region of large maximum hygroscopic moisture values.

 The goal is achieved by the fact that an additional roller with a hygroscopic coating is inserted into a device containing a roller sensor and measuring circuit, placed in a perforated housing with an electric heater located along 5 surface rollers.

FIG. 1 schematically shows the proposed device; in fig. 2 - installation diagram of ring electrodes.

Claims (2)

The device consists of a lower roller 1 and an upper intermediate roller 2, covered with a hygroscopic material 3, pressed against the surface of the material under test 4. The intermediate roller is covered with a perforated casing 5, under which an electric heater coil 6 is inserted along the surface of the intermediate roller 6. Behind the spiral in the direction of rotation of the intermediate roller is installed roller sensor conductometric moisture meter 7. The ring electrode 8 of the sensor (Fig. 2) is placed on an insulating cylindrical roller 9, which freely rotates with along its axis. The ring electrodes 8 are tightly pressed against the hygroscopic coating 3 with a special clamping device. Current from the ring electrodes is carried out using collector brushes 10 mounted on the insulating base 11. The conductivity sensor is connected to an electronic unit of the converter 12, which converts the resistance of the sensor into a corresponding DC electrical signal, supplying heater 6 and measuring instrument 13, graduated as a percentage of moisture content. The device works as follows. The wet material 4, when moving between the rollers 1 and 2, pressed against it with a constant pressure, transfers some of the moisture to the hygroscopic coating element 3 of the intermediate roller in the contact zone. Turning along the material, the intermediate roller moves the wetted element to the nodule area, where it is dried by electric heater 6. The nodal moisture is removed through the holes in the casing 5. At the exit from the nested area, the subclustered hygroscopic coating enters the contact area with annular electrodes 8 of the conductometric sensor 7, where its humidity is measured by the conductometric method. The resistance of the sensor is measured between the middle and two extreme ring electrodes. This resistance is a function of the moisture of the monitored material. Thus, with an increase in the moisture content of the material, the amount of moisture transferred by diffusion from the material to the hygroscopic coating of the intermediate roller during contact time increases. After drying at constant parameters in the contact zone of the conductivity sensor, the humidity of the hygroscopic coating also increases, which leads to a decrease in the resistance of the sensor. The measuring device 13, connected at the output of the electronic unit of the converter 12, shows a corresponding increase in humidity. This device allows us to significantly extend the range of moisture measurement of sheet materials up to the maximum possible values after mechanical pressing. In addition, due to the stability of the physical properties of the hygroscopic coating of the intermediate roller (it is recommended to be made of wool cloth) in the device, it is possible to weaken the measurement error by changing the concentration of dyes and other impregnations of the material being monitored. The advantages of the device also include a weak dependence of the readings on the thickness and density of the material being monitored. It is most advisable to use a device for controlling the moisture content of a fabric after mechanical pressing in finishing operations, where it can successfully compete with more complicated and expensive methods: ultra-high frequencies, infrared radiation, radioactive. Claims An apparatus for measuring the moisture of sheet moving materials, comprising a roller Conductometric sensor connected to a measuring circuit, characterized in that, in order to expand the range of measured values, an additional roller is introduced in contact with the sensor, made with a hygroscopic coating and placed in perforated casing with electric heater. Sources of information taken into account in the examination 1.Milman Ya.V., Shvyrev S.S. Fundamentals of automation of technological processes of textile industry. “Light Industry, 1964, p. nineteen. 2.Klaus Gott. Feuch temejjtechnik, Reihe automatisiezungstechnik. Band 48 VEBVERLAG Technik Berlin, 1966. / J