SU1493480A1 - Method and apparatus for foroming blanks form chips and binder - Google Patents

Abstract

The invention relates to the production of parts and products from a mixture of wood chips and a binder and can be used in the woodworking industry. The purpose of the invention is to increase the productivity of the method and improve the quality of products. Simultaneously with the screening of the mixture through the vibrating screen, the speeds of screening part of the various fractions are controlled. The vibrating screen consists of the bottoms 2, 3, 4 with the ratio of the diameters of the holes of the upstream bottom to the lower located 1.3 - 1.5 and with the ratio of the distance between the bottoms to the size of the bottom bottom 5 - 5.75. The method is carried out by passing the mixture at least three times through the bottoms 2, 3, 4 with the dimensions of the holes decreasing from the top 2 to the bottom 4, and the filling of the space between the bottom bottom 4 of the vibrating screen and the surface of the mold 9 is carried out by sequential fractional laying of particles in the workpiece. The dilution of the mixture is carried out by distributing it at least on three bottoms 2, 3, 4, oscillating with the same frequency and amplitude, equal, respectively, to 880 - 960 counts / min and 7 - 12 mm. 2 sp.f-ly, 2 ill.

Description

7/2 3 4 I I / / I

WITH

oh

four:

00

sriel

The invention relates to methods for forming blanks from a mixture of wood chips with bonding and to an apparatus for carrying it out and can be applied in the woodworking industry in the production of chipboard.

The purpose of the invention is to increase productivity and improve product quality.

FIG. 1 shows a diagram of an apparatus for forming wood chip chips and a binder prior to the formation process; in fig. 2 is the same after forming the preform.

The device includes a vibrating screen 1 provided with bottoms 2, 3 and 4 arranged one above the other with a decrease in the size of the holes from the top to the bottom. The ratio of the pitch diameters of the holes of the upstream bottom to the lower one is 1.3-1.5, and the ratio of the distance between the bottoms to the size of the diameter of the bottom bottom opening is at least 5 (5-5.25). at the same time, the holes of the lower bottom have a diameter greater than 1.1-1.2 times the maximum width of the wood particles. The vibrating screen 1, which is hinged on the suspensions 5, is connected by means of connecting rods 6 with the drive 7. From a portion of the mixture 8 in the mold 9, product 10 is pressed with the lower 11 and upper 12 layers.

The method of forming the blanks is carried out as follows.

In the vibrating screen 1, which is outside the press, a predetermined portion of the mixture 8 is loaded, after which it is fed into the press zone and installed above the mold 9. When the vibration actuator 7 is turned on, the particles randomly move, self-sorting fractions by size and sieving them from the bottom layer through the holes of the bottom 2. In the initial period of time after the application of vibration, small and large particles of the lower layer are sieved. Further, due to the self-sorting of particles by particle size, the fraction of the fine fractions in the screened mass increases, reaches a maximum, and then decreases. The screening rate of particles is characterized by the sifting ratio, which expresses the change in the fraction of particles per unit of time through a unit area of the sieve holes. The screening factor of the particles is determined by the ratio of the sizes of the particles and the bottom holes. The dependence of the screening coefficient and the relative radius of the particles is determined by the hyperbola. By virtue of this dependence and the self-sorting of particles by size when sifting the mixture through the bottom, e 2, it is partially divided into fractions. As a result, the amount of the mixture on the bottom 2 decreases, and the sieved particles in a uniform flow fall on the bottom 3, the hole size of which is smaller than

at the bottom 2. The mixture with the mixture falls on the bottom 3 in a rarefied state, in which the number of interactions between particles is minimal. This contributes to the intensification of the screening of particles through the bottom 3. When the mixture hits the bottom 3, the relative radius of the particles increases and the screening coefficient decreases. Consequently, the rate of sieving of particles through the bottom 3 decreases. Moreover, when the particles hit the bottom 3, the mixture particles are oriented in the gateway space mainly in a horizontal position, which is achieved by their interaction with the openings of the bottom 2 and the environment. To ensure a predominantly horizontal orientation of the particles, the height of their free fall (i.e. the distance between the bottoms) must be at least 5 sizes of the diameter of the bottom bottom opening 4. The horizontal orientation of the particles when falling on the bottom 3 provides an additional reduction in the screening rate of coarse fractions and has little effect em at the rate of screening fines. In this way, conditions are created for rapid sifting of the mixture, the sieving rate of the particles of which decreases as their size increases. As a result, the separation effect of the particles into fractions on the bottom 3 is enhanced. At the same time, if the ratio of the sizes of the diameters of the holes of the leaching bottom 2 to the underlying 3 is 1.3-1.5, then the mixture is sieved so intensively that no accumulation of particles on the bottom 3 occurs.

The sieved particles arrive in a rarefied state on the bottom 4, the size of the holes of which is 1.3-1.5 times smaller than the bottom 3, but 1.1-1.2 times the maximum width of the particles. The particles enter the bottom 4 in the order in which they are sifted through the bottom 3. The smallest particles arrive first on the bottom 3, and then the size of the incoming particles increases. The largest particles fall last on the bottom 4. As particles arrive at the bottom 4, they are sieved. In this case, on the bottom 4, the same phenomena occur as on the bottom 3, as a result of which the separation of the mixture into fractions reaches an even greater degree.

The fractioned wood particles are placed on the mold 9 in the sequence in which they are sifted through the bottom bottom 4. As a result, the blank 10 is formed by successive fractional packing of particles until the space between the mold 9 and the bottom bottom 4 of the vibrating screen 1 is completely filled. In this case, the vibration is dried in the following mode: frequency 880–960 count / min, amplitude 7–

12 mm. Finally, a blank is obtained, the lower layer 11 of which, located directly on the mold 9, consists of particles with minimum sizes, and then the particle sizes increase further along the thickness of the blank. The top layer of the workpiece consists of particles with maximum sizes.

Changing the shape of the holes and placing them in the desired direction, form with oriented packing

ten

by sifting the mixture with simultaneous application of vibration, characterized in that, in order to improve the performance of the method and improve the quality of the products, during the formation, at least three-fold sieving of the mixture is performed while simultaneously sieving speed by vibrating sieves with a frequency of 880-960 count / min and an amplitude of 7-12 mm.

preparation

particles A device for forming a planar after complete filling of the space from a mixture of wood chips and the joint between the mold 9 and the bottom plate, including a number of

4 with a mixture of 8 vibrating screens 1 are removed from the press. A friend over the other vibrator head with holes

„Pressing of the workpiece as well as the forming conveyor, in order to increase

productivity and improvement of product quality, the vibrating bottom is made with the ratio of the diameters of the holes of the flush-mounted bottom to the lower position equal to

into the product.

The invention provides improved performance and quality of extruded

products.

Claims (1)

Invention Formula I. Method of forming blanks from a mixture of wood chips and a binder 20 1.3-1.5, and with the ratio of the distance between the bottoms to the size of the diameter of the hole of the lower bottom, equal to 5-5.25. by sifting the mixture with simultaneous application of vibration, characterized in that, in order to improve the performance of the method and improve the quality of the products, during the formation, at least three-fold sieving of the mixture is performed while simultaneously sieving speed by vibrating sieves with a frequency of 880-960 count / min and an amplitude of 7-12 mm. productivity and improvement of product quality, the vibrating bottom is made with the ratio of the diameters of the holes of the flush-mounted bottom to the lower position equal to 20 1.3-1.5, and with the ratio of the distance between the bottoms to the size of the diameter of the hole of the lower bottom, equal to 5-5.25. FIG. 2