SU1352334A1 - Method of continuous measurement of humidity content of wood chips - Google Patents

Abstract

The invention relates to a measurement technique and can be used to continuously measure the moisture content of bulk materials, such as wood chips, in the manufacture of particleboard. The goal is to increase the accuracy of measurements. Chips are fed to the surface of the rotating drum, a layer of chips is formed on the surface of the drum. The formation of a layer is carried out in an electric field, which is created by applying a constant voltage of opposite polarity to alternating conductive sections formed on the surface of the drum. The force of the effect of the formed layer on the strain gauge plate installed with a gap to the drum is measured. According to the measured characteristics, the moisture content of a substance is judged. 2 Il. I (L S

Description

113

The invention relates to a measurement technique and can be used to measure the moisture content of bulk materials, such as wood chips, in the manufacture of particle boards.

The purpose of the invention is to increase the measurement accuracy.

Fig. 1 shows a device that implements a method for continuously measuring the moisture content of wood chips; 2 - calibration curve for indirect measurements.

The device includes a dielectric rotating drum. 1, on the surface of which along its generatrix there is a series of conductive section 2 equally spaced one from another. On both end surfaces of drum 1 there are current collecting rings 3 to which, alternately through one, the above electrodes 2 are connected : some sections are connected to the ring 3 at one end of the drum, all adjacent areas to the ring at the other end of the drum. Through brushes 4 from a low-power current source 5 to the rings 3 a high constant voltage of opposite polarity of the order I -2 kW is applied.

A measuring element in the form of a console is installed at the surface of the drum.

but fixed flexible tensometric- 5 electrical material - Teflon.

This plate 6 is equipped with a sensitive element - a strain gauge 7 connected to the measuring device 8, calibrated in units of humidity. The longitudinal axis of the flexible plate is perpendicular to the axis of rotation of the cylindrical drum.

The gap between the flexible plate and the drum when measuring the moisture content of wood chips is 0.1-0.8 mm, since with smaller gaps it is possible to touch the plate behind the drum, and with large gaps it is possible for the chip to slip between the drum and the plate.

The method is implemented as follows.

A layer of the measured substance (wood chips) is formed with the mass of particles normalized within the prescribed limits and their geometrical sizes. The bed is fed to the surface of the rotating drum. Simultaneously to the conductive areas 2 from the current source 5

Conductive areas of copper were deposited on the surface of the drum with Hbj. The calibration curve obtained for this design with a field that is normalized to 40 is shown in Fig. 2. The relative error of moisture measurement did not exceed 5.5%.

Claims (2)

45 claims A method for continuously measuring the moisture content of wood chips, comprising: The gQ of the rotating drum serves chips, forms on the surface of the drum on a layer of chips, and according to its physical characteristics, the humidity of a substance is different. gg by the fact that, in order to increase the accuracy, the formation of a layer is carried out in an electric field, which is created by applying a voltage of opposite polarity to a high voltage. With this, an electric field is formed on the surface of the rotating drum 1 between the conductive parts 2. The wood chips 9, the pad from the technological conveyor 10 into the bunker II, fall into the zone of action of the electric field forces. Under the action of electric field forces, a part of the falling wood, chips are attracted to the surface of the drum 1, closing the gaps between the conductive parts 2. The chip 9 on the drum 1 is brushed off from its surface by means of an elastic plate 6, which in this case bends accordingly, depending on the moisture content of the wood chips. A strain gauge 7 fixed on plate 6 converts the size of the breakdown of the elastic plate into an electrical signal that is fed to a recording device 8, calibrated in units of humidity. Example. When measuring the humidity of standard wood chips used to manufacture chipboard, a constant voltage of 2 kW was applied to the conductive parts of the rotating drum. The gap between the flexible plate and the surface of the rotating drum was 0.6 mm. The rotating drum was made of a dian. The surface of the drum was applied conductive areas of copper. The calibration curve obtained by this design with a standardized field strength is shown in Fig. 2. The relative error of moisture measurement did not exceed 5.5%. formula of invention A method for continuously measuring the moisture content of wood chips, comprising: rotating drum serves chips, form a layer of chips on the surface of the drum and according to its physical characteristics judge the humidity of a substance that differs In order to increase the accuracy, the layer is formed in an electric field, which is created by applying a voltage of opposite polarity to alternating conductive parts made on the drum surface, and the force of the formed layer on to the drum strain gauge plate. YU Agh - .. y.ts ® -: -, 2 fig Order 5558/41. Circulation 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 . Production and printing company, Uzhgorod, st. -Project, 4