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The article deals with the algorithmic method for precision enhancement of paper pulp blade consistometers . In the said method, the current strength in the winding of a moving coil of a magnetoelectric transducer in the steady regime of sensor`s blade motion condition is measured during its movement in downstream and upstream directions. Thus, we can minimize the error resulting from the impact of changes in flow velocity relative to paper pulp measuring blade of the consistometer. Schematic diagram of a paper pulp consistometer with paper pulp flow velocity compensation is presented. Dependence of voltage and current versus time on the outputs of the main blocks of presented paper pulp consistometer with compensation of paper pulp flow velocity influence is considered. Influence of paper pulp flow velocity and consistency on the dependencies of current versus time for the coil of a magnetoelectric transducer of a paper pulp consistometer is described.Keywords: blade consistometer; blade consistency meter; paper pulp; consistency; non-Newtonian fluid. Definition of the problem to be solvedPaper making industry is very important in modern industrial countries. First of all, it produces various package materials, which can be easily utilized by repeated recycling, giving as value production as from initial (starting) raw materials [1]. The processes of paper pulp recycling can be realized on large high capacity technological lines, as well as on relatively small ones. Moreover, this small production line shall be economically effective due to reduction of expenses for transportation of raw materials and ready-made products, and decrease of technological loading on environment. An important technological parameter in paper making industry is consistency (concentration) of paper pulp [2]. It is measured indirectly by measuring paper pulp viscosity, and is one of the few examples of medium concentration determination by measuring its viscosity [3,4]. The metrological and operational parameters of instruments developed for measuring paper pulp consistency can be improved by modification of measuring process with further algorithmic processing of the directly measured values. Below, the improved version of a blade consistency meter for paper pulp is presented in which the influence of paper pulp flow rate on the value of measured pulp consistency is considerably reduced. Analysis of the recent designs of the blade consistency meter devicesThere are several technical arrangements of blade consistency meter devices for paper pulp appropriate for industrial application. The most famous of them are as follows.Blade consistency meter design without activator (activating agent) [5,6,7].In this consistometer design, the blade is placed along the paper pulp flow. Paper pulp consistency is determined by the viscous friction force acting on the blade by the pulp flow. The value of the force acting on the blade varies approximately within the limits of 0 to 30 N when the paper pulp consistency varies 0 to 16 % Cs. For di...

This paper presents the results of theoretical and experimental testing of an optical rotation angle sensor of rotational paper pulp consistency meter. It is suggested that a specialized device consisting of two discs with the diameter as large as possible should be applied in the rotational consistency meters. There are holes in the disks. One more optocoupler should be applied for registering the beginning of the signal processing of separate measurements in order to reduce the root-mean square error. The measurement cycle of the sensitive element rotation angle is conducted within a predetermined number of full turns of the main shaft. The research results can be applied during development of the paper pulp rotation consistency meters based on the compensation of the viscous friction torque and based on the direct measurement of the viscous friction by defining the rotation angle of the sensitive element.Keywords: paper pulp consistency; measurement; rotation consistency meter; optical sensor; magneto-electric transducer. Definition of the scientific problem studied in the researchMeasurement of the paper pulp consistency on various stages of its preparation in tissue paper or cardboard manufacturing process can significantly influence the quality and the cost of production. Continuous control of the paper pulp consistency is usually performed by means of the mechanic method by defining the pulp viscosity [1,2]. There are two types of consistency meters that are based on this method: the rotational or mixer consistency meter, and the blade consistency meter. The rotational consistency meters can be of different design. However a common element for all of them is the device for measurement of the rotation angle of the sensitive element in relation to the rotation axe. During the improvement of such consistency meters and during development of new designs, it is important to increase the accuracy of measurement of the rotation angle for both rotation directions. This paper suggests a way of processing the signal from the optical sensor for the rotation angle measurement and discusses the obtained analytical ratios for processing of such signal. Analysis of the recent publications and research on the topicThe paper pulp is a non-Newtonian fluid. Its consistency can be measured indirectly based on the viscosity. Commercially produced rotational devices are based on various designs that include a device to determine a rotation angle of a sensitive element.

Maintaining of the proper predetermined paper pulp consistency on the different stages of the paper or cardboard manufacturing process significantly affects on quality and self cost of manufactured articles. The improvement of precision and repeatability of the paper pulp viscosity and consistency measurements is relevant to paper industry. Objective of the work is to improve the industrialtype paper pulp rotational consistometer. A new method for measurement of paper pulp concentration by means of a rotational viscometer was suggested which enables determining the flow consistency index K and flow behavior index n in the Ostwald-de Waele power law. The influence of the following torques on the measurement results is eliminated thanks to the new method: the friction torque in the seal of the sensitive element, the friction torque in the bearings of the shaft and the torque created under the influence of the flow with distorted flow speed profile. This is achieved by measuring the torque which acts on the sensitive element approaching the selected frequencies of sensitive element rotation both from the lower and higher frequencies. The mean torque value is calculated based on the obtained values. The measurements are conducted for two sensitive element rotation frequencies adjusted in advance. The frequency of sensitive element rotation is changed by means of a frequency converter. It is shown that by using two different rotation frequencies of the sensitive element of a rotational viscometer it is possible to define the flow consistency index and the flow behavior index. Paper pulp viscosity and consistency is defined on the basis of these two indexes. It is also suggested to average the results of viscous friction torque measurement approaching the rotation frequency of the viscometer sensitive element to the working frequency chosen for measurement from the lower and higher frequency ranges. By averaging the results of such measurement the friction torques in sealing and bearings supporting the sensitive element shaft are compensated. By changing the rotation direction of the sensitive element and by further averaging the obtained results it is possible to eliminate the influence of the asymmetrical distribution of paper pulp flow speed in the pipeline. This improves accuracy of the paper pulp consistency measurement.