RU1787546C - Pulp classifying device - Google Patents

Description

fishing is reciprocal. The length of the protrusions is equal to the amount of vertical movement of the cover. The overall linear size of the lid with openings in its walls exceeds the distance in the light between the tops of the protrusions. To remove pulp with a small spectrum of fractions from the classifier, a general collecting tray 12 is located, located along one of the walls of the classifier, which merges the pulp from channels 9. Pulp. With large particles is discharged to the bottom of the device through the pipe 13.

In FIG. 3 and A, a device is shown comprising two insulated chambers 1 and 14 of the same size, separated by a wall. The feed pulp is supplied to the chambers through the feed pulp lines 2 and 15. Pulp pipelines equipped with automatic valves at the entrance to the classifier 16.17 and fed from the common feed tray are connected to soothing cups 3 and 18, equipped with braking discs 4 and 19 from the bottom. The covers of the device 5 and 20 are not connected to the packages 6 of the precipitation plates. The covers in the initial (lowered) state rest on the shelves in the walls of the classifier), as well as on the heads of the 8 channels 9 for removing pulp with small particles. Shelves in the walls and the ends of the channels are located in one horizontal plane. The length of the channels corresponds to the width of the lightening mirror of each chamber. Other structural parameters of the channels, as well as the packages of the deposition plates, are assigned in the same way as described above for the previous design.

For the removal of pulp with fine particles in opposite walls of the device, prefabricated trays 12 and 21 are connected to channels 9. The large product is discharged through nozzles 13 and 22, equipped with check valves 23 and 24 and combined into a common outlet pipe 13 behind the valves.

In FIG. b and 6 show the construction of the device with a pulp-conducting tray located above the cover of the device. Tray 25 in its bottom is equipped with a nozzle 26 s; automatic valve 27. The pipe is connected to an insulated cavity

28. located in the cover of the device 5 in its central part using a funnel

29. mounted on the central axis of the device. Cavity capacity. 58, designed for 4N-4n «p e rVni / it) 6BariM of the mass of the lid, is 50-80 m3. The degree of penetration of the nozzle 26 into the funnel is selected from the condition of ensuring free movement

 lids in the widest possible range, as well as preventing overflows and splashing pulp from the funnel onto the lid. The feed unit pulp in the classifier is arranged similarly as described above. The channels for collecting the pulp with small particles 9 with the heads 8, as well as the packages of precipitation plates are the same as in the previous designs. The cover 5 moves freely,

0 precipitation plates mounted on the housing. A cavity 28 is connected to a nozzle 13 for draining pulp with large particles by means of a nozzle 30 and a short pipe 31 with a funnel 32 at its end. Pat-5 cutting 30 is mounted on the cover 5 and moves with it and is equipped with a valve 33. The fine-grained pulp is removed through a common collecting tray 12, passing along one of the walls

0 classifiers.

Devices work as follows ..

The pulp (Figs. 1 and 2) is fed through a slurry conduit 2 into a stilling glass 3 and then

5 to the braking disk 4. The cover 5 with the packages of plates 6 is lowered in the initial state. Until the classifier is completely filled, pulp is discharged through pipe 13. After the classifier is filled

0 the pressure in the device begins to increase, as the speed of the pulp and the pressure loss in the nozzle 13 increase. The cross-sectional area and the length of the nozzle 13 are set so that in the output mode of the initial flow

5 pulp through it, the pressure loss in the nozzle was 0.2-0.4 kg / cm3. At this overpressure, cover 5 rises and is in a floating state. Its movement is determined by two types of displacements: in the horizontal plane, due to fluctuations in the upward flow of the pulp due to the unevenness of the velocity field of the flow, and vertical, due to changes in the flow rate of the initial pulp. The movement of the lid in the horizontal plane is limited by walls equipped with protrusions, which are pushed against by openers 10, and the lid receives a shock pulse, causing vibrational disturbances in the plate packs. The collision frequency is 1-2 beats per minute. The frequency of vertical movements is small and is once every 30-60 minutes.

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To prevent the lid from hanging on the profiles 11 when it is lowered, their upper faces are arranged at an acute angle of less than 30 °, which ensures that the lid slides over the surface of the profile.

The combination of impacts during vertical and horizontal movements of the lid creates an oscillatory mode for the packs of plates 6, which ensures intensive and uniform sliding of the material deposited on them. The intensity and amplitude of oscillations on the scale of the device do not change the nature of the upward flow and do not increase its turbulence.

The pulp with small particles, pouring out from under the lid, enters the channels 9 and is transported through them to the collection tray 12 for removal. The pulp with large particles is removed through the nozzle 13.

A device with divided cameras (Fig. 3,4) works as follows.

Through the slurry pipelines 2 and 15, equipped with automatic valves 16 and 17, the pulp is alternately fed into one or the other chamber 1 or 14. When the pulp is fed into one of them. The flow of pulp to another one, with the lid lowered at that time, is completely blocked: from above, the automatic slurry line 2 or 15 is blocked by automatic shutters 16 and 17, the check valve 23 or 24 is activated from below, preventing overflow. pulps: from one chamber to another . Switching the power supply from one camera to another is carried out in two stages. The first closes the automatic valve in the inlet slurry conduit of the working chamber, for example 1. At this time, the incoming feed slurry accumulates in the inlet chute. When the pulp leaves the chamber 1, its cover 5 is lowered to collide with the protrusions 7 and the heads 8, with which the plates are received, which receive an oscillating impulse in a collision. At this time (in the second stage), the valve on the slurry pipe 15 opens and the pulp from the slurry pipe enters the chamber 14, its cover pops up under the pressure of the pulp and the pulp with small particles comes out of the camera into the slot between the cover 20 and the heads 8 through channels 9 and the tray 21. The pulp flow entering the chamber 14 is discharged in the first stage after opening the gate valve on the slurry pipe 15 through the opened check valve 24 of the chamber. In this case, the check valve 23 of the chamber 1 closes and the pulp discharge from it stops. The device operates in this mode until the pressure loss in the pulp discharge path with large particles exceeds the pressure value of 0.2-0.4 kg / cm necessary for lifting the cover. As the lid is lifted, overflow of pulp containing fine fractions into the tray 21 begins through the formed gaps between the lid and the heads of the trays.

The dynamics of particle deposition in this device has the following features 5 related to the cyclic operation of the chambers. The particle motion path is a broken sawtooth line. The lifting sites correspond to the time interval of the pulp entering the chamber;

0 fall - time interval for switching the pulp to an adjacent chamber. The smooth envelope over the protrusions of the saw corresponds to the particle path in a conventional classifier with the same working volumes, the same surface mirror and the same pulp flow rate.

A device with a feed tray located above the cover of the feed pulp is shown in FIG. 5 and 6. In the initial position, the cover 5 is lowered and the cavity 28 in it is filled with pulp. The source pulp through the tray 25 and the pulp line 2 is fed into the system, consisting of a glass 3 and a braking disk 4, working

5, as described above, the operations of raising and lowering the lid are carried out automatically. To lift the pulp cover from the cavity 28, pipes 30 and 31 are fed into the pulp pipe 13 with large

0 fractions until the entire pulp flows out of the cavity. After that, the valve 33 on the nozzle 30 closes. A lightweight cap pops up to provide hydraulic resistance to the nozzle

5 13, the value of which allows the lightweight cover to float and maintain in suspension and lower the cover with the cavity filled with pulp into the initial position. The mating of the crow-shaped nozzle 29 and the nozzle 26 allows the cover to move freely when it is raised and lowered. The pulp with small particles is poured out from under the lid into the channels 9. The valve 27 on the nozzle 26 is closed at this time and the entire initial pulp enters the classifier. To lower the lid, a valve opens on the nozzle 26. and the pulp with a high flow rate, up to 1/2 of the total initial

0 flow rate, enters the cavity 28, the lid is thick. At the same time, the flow rate of the pulp supplied to the classifier is reduced by the amount of flow taken to the cover through the nozzle 26, therefore, the hydraulic resistance is also reduced. the pressure of the nozzle 13, the lid is lowered until the moment of impact with the protrusions 7 and the heads 8, with which the packages of plates 6 are rigidly connected. In this case, the vibrational impulse from the impact is transmitted to

plates. As a result, accelerated and more intensive sliding of the material deposited on the plates occurs. When the cavity 28 is filled with pulp (at the moment the lid collides with the protrusions and heads), the valve 27 closes, the valve 33 opens and the ascent of the cover begins.

The working position of the lid is the suspended position with the pulp being pulverized with small particles in the channels 9. The lid is lowered only to communicate the vibrational impulse to the plates 6 (10-12 times per hour). The dynamics of the particle deposition process is similar to the dynamics of deposition for a two-chamber classifier, but with less pronounced sawtoothness. ; .

Advantages of the proposed designs: simplification of the device due to the exclusion of the actuator and increased reliability.

For m ul and zobret e n and

Claims (4)

1. A device for classifying pulp, including a housing, inclined precipitation plates installed in the housing, a device for shaking the precipitation plates, a pulp supply pipe, a drain tray and an discharge nozzle, characterized in that, in order to simplify the design and increase reliability, the device, the device for shaking the plates is made in the form of a cover located freely on the surface of the pulp above the plates with the possibility of vertical movement under the influence of the pulp. 2. The device according to claim 1, the clause being that the lid and walls of the housing are made with protrusions arranged to interact with each other, while the precipitation plates are mounted on the lid. 3. The device according to p. 1, with the exception that it is equipped with a vertical partition dividing the housing into equal chambers, a system of automatic valves installed in the slurry supply pipe, and non-return valves installed in the discharge pipe for providing alternate autonomous operation of the chambers, while the precipitation plates are connected to the housing, and the lid is made of two parts located on both sides of the vertical partition. 4. The device according to p. 1.0, including that it is equipped with a pulp-feed tray installed above the lid, and a lid is made in the lid that communicates with the pulp-feed tray and with an unloading pipe, In this case, the precipitation plates are rigidly connected to the housing. $ game 4 tft.f