RU2142346C1 - Belt screen - Google Patents

Abstract

FIELD: fine separation of material by size fractions in any branch of industry. SUBSTANCE: belt screen includes screening surface in the form of endless traction member having sections with working zone and discharging zone, embracing drum, strings arranged between section bases and mounted with tension in working zone and without tension in discharging zone. Each section is provided with mechanisms for tensioning strings with predetermined effort only in working zone. Racks with grooves for fixing strings are arranged under strings. Number of racks prevents string slackening and oscillation in working zone. Strings are covered by antiabrasion coat. EFFECT: enhanced accuracy of material separation by size. 2 cl, 3 dwg

Description

 The invention relates to the field of separation of materials by size and can be used for thin screening.

 The prototype is a tape screen (copyright certificate N 1488023 A1 of the USSR of 02.22.89).

 The disadvantage of this screen is that despite the tension of the strings sag, and when passing the material in the form of pulp through the screen surface, the strings oscillate horizontally. Since the screen is used for thin screening, the vibration of the string within tens of microns gives an error in the selection of a certain class of material.

 To eliminate sagging and vibrations of the string in the proposed device on each section under the strings perpendicular to the tension rails are installed with grooves, the number of grooves is equal to the number of strings, the gap, the distance between the grooves is equal to the working gap of the screen. The number of rails installed on one section depends on the length of the section and the permissible string vibrations. Along the entire length of the string with a certain step, you can set the ribs, the size of the ribs is equal to the working clearance. In the working area, when the string is tensioned, the ribs come in contact with the surface of the adjacent string, which does not allow vibrations.

 In FIG. 1 shows the proposed device, side view; in FIG. 2 - the same, top view; in FIG. 3 - node 1 in FIG. 2.

 The belt screen includes a frame 1, a screening surface 2 in the form of an endless traction unit, stretched over the drums 3. The screening surface 2 consists of sections 4, mounted on both sides of the chains 5. The screening surface is moved by engaging the teeth of the drum with chains. The speed of the belt is regulated depending on the requirements of the material separation technology. Each section is equipped with sides 6, which increases its productivity and reduces pulp spraying. Screening surface 2, i.e. sifting elements made of strings 7 fixed between two bases 8 of section 4. Moreover, a fixture 9 is installed on each section, which creates tension in the working area of the strings of the section with a given force, and in the unloading zone - there is no string tension. The device for string tension can be magnets, electric magnets, pneumatic and hydraulic cylinders, a lever mechanism using the weight of the section, in this case a mechanical device in the form of springs 9. On each section, rails 10 with grooves are installed perpendicular to the string tension, the number of grooves is equal to the number of grooves strings 7, sections, i.e. each string, lie in its groove of the reiki 10.

 To increase the throughput of the screen in the working area of the section, vibration and shock loads may be exposed. For dry classification, a vacuum may be applied.

 The screen is equipped with a washing 12 and replaceable 13 devices, receivers of the under-sieve 14 and over-sieve 15 of the product.

 A screen with a working gap of 0.1 mm works as follows.

 Material with a particle size of 75% of the class 0.074 mm is fed to a screen in the feed zone. Each section 4, having received the calculated portion of the material, enters the washing zone 12 of the oversize material, material with a size of 0.1 mm enters the receiver 14. The section with the washed oversize material + 0.1 mm enters the unloading zone, where the string tension is for the passage time there is no discharge zone, the strings sag, stuck hard grains are released and washed off with water to the receiver 15. The cleaned section 4, leaving the discharge zone, restores the working clearances 11 due to the tension of the strings 7 with the device 9.

 To increase the service life of the strings are coated with anti-abrasive coating.

Claims (2)

 1. A belt screen, including a screening surface in the form of an endless traction unit from sections with a working zone and an unloading zone, covering drums, screening elements made of strings fixed between the bases of the sections and installed with tension in the working zone and without tension in the unloading zone, characterized in that each section of the screening surface is equipped with devices (mechanisms) that ensure the tension of the strings with a given force only in the working area, rails with grooves are installed under the strings to fix them , in an amount that ensures the elimination of sagging and vibrations of the strings in the working area, and the strings are made with anti-abrasive coating.  2. The belt screen according to claim 1, characterized in that along the length of the string with a certain pitch, ribs are installed with the possibility of their contact with an adjacent string when string is tensioned.

Images