First, the cylinder type vacuum filter
Vacuum filter is cylindrical metal ore dressing plant most especially black concentrator applications dewatering equipment. According to its unloading method, it can be divided into various types. Figure 1 is a continuous filtering device that can simultaneously perform operations such as filtration, washing, and cake removal in the same rotating device. The cylinder is a cast or steel plate welded cylinder whose outer surface is divided into a plurality of filter chambers by a grooved lattice plate. The filter cloth is covered on the grid plate. The lower part of the cylinder is immersed in the slurry tank and is rotated around the horizontal axis by the gear system. The size of the filter chamber should not be too wide, generally not exceeding 550 mm. The number is related to the diameter of the cylinder. When the diameter is large, the outer surface area of the cylinder is large, and the number of filter chambers is correspondingly increased. Conversely, the number of filter chambers is correspondingly reduced. For example, a commonly used 40 m 2 filter has 24 filter chambers.
The outer filter type vacuum filter uses a scraper to drop the filter cake. The filter cloth is fastened to the filter plate by means of a wire . These wires also serve to prevent the filter cloth from being scratched by the scraper. The outer filter vacuum filter has a stirrer in the slurry tank, which is located below the cylinder and is driven by the bevel gear and the chain. When the agitator is working, the slurry can be kept in suspension in the trough. The number of times of agitation depends on the nature of the material, and is generally 20-60 beats/min. For materials with a large particle size and coarse density, the number of stirrings can be large.
The dispensing head is an important part of the filter. The filtrate is discharged through it, and suction and pressure are alternately carried out during the filtration process, so that the slurry forms a filter cake, and is changed from a vacuum suction state to a compressed air blow state, thereby effectively controlling the order of the filtration operation. The dispensing head is divided into two types: planar contact type and cylindrical surface contact type. Cylindrical surface dispensing heads are not easily repaired after wear. It is easy to get stuck by the ore particles and is used less. Most filters use a flat distribution head. In order to facilitate maintenance, the flat distribution head disk and the gas disk are often made to be in direct contact with the wearing parts.
Figure 1 Structure of the barrel type external filter vacuum filter
1. Cylindrical body transmission device; 2. Dispensing head; 3. Cylinder body; 4. Bearing seat; 5. Scraper; 6. Slurry trough;
7, stirring transmission device; 8, agitator; 9, winding device
The cylindrical external filter vacuum filter can be divided into the following working areas according to the filter cake forming process. as shown in picture 2.
Figure 2 Working diagram of the cylindrical external filter vacuum filter
1, the filter chamber; 2, the distribution valve; 3, 4, the tube connected to the vacuum pump;
5, 6, the pipe connected to the air compressor; 7, washing water pipe [next]
Filter zone I. The cylinder in this zone is immersed in the slurry, and the filter chamber formed between the filter cloth and the grid plate is evacuated, and the filtrate is sucked into the filter chamber through the filter cloth, and then discharged through the dispensing head. The solid material and residual moisture are adsorbed on the surface of the filter cloth.
Sucking area II. In this area, the remaining filtrate is drained and the filter cake is blotted dry.
Washing area IV. In this zone, fresh water is sprayed on the filter cake by the tube 7, and after filtering the filter cake, it is sucked into the filter chamber, discharged through the tube 3 together with the filtrate or separately discharged by the tube 4.
Blow in the area VI. In this zone, the filter chamber communicates with the compressed air, and the compressed air blows the filter cake to facilitate unloading.
Discharge zone VIII. In this zone, the filter cake is peeled off by the scraper.
In the figure, III, V, VII, and IX are non-working areas and are located between II, IV, VI, and VIII. Therefore, when the filter chamber is changed from one zone to another, it does not communicate with each other.
The beneficiation product usually does not require washing, so when the concentrator uses a vacuum filter, the washing zone is incorporated into the blotting zone.
Each cycle of the dipping filter, under the adjustment of the dispensing head with the vacuum tube, the cycle of filtration, dehydration, blow drying and filter cloth cleaning is gradually completed.
The specifications and technical performance of the commonly used tubular external filter vacuum filter are listed in Table 1.
Table 1 Technical data of cylinder type external filter vacuum filter
| Model | Cylinder size, mm | Filtration area m 2 | Cylinder speed, r/min | Stirring times Times / min |
| Diameter × length | Group I | Group II |
| GW-20 | 2500×2650 | 20 | 0.14, 0.19, 0.27, 0.38, 0.54 | 25 or 45 |
| GW-30 | 3350×3000 | 30 | 0.12 0.16 0.23 0.29 0.39 0.56 | 0.11 0.14 0.21 0.26 0.34 0.5 |
| GW-40 | 3350×4000 | 40 |
| GW-50 | 3350×5000 | 50 |
| GW-3 | 1600×700 | 3 | 0.13-0.7 | |
| GW-5 | 1750×970 | 5 | 0.13-0.7 | |
| Model | With electric motor, kW | Dimensions, mm | Weight t |
| Cylinder | Blender | Length × width × height |
| GW-20 | -8/4/2.5/4.0 | 2.2 | 4480×4085×2890 | 10.6 |
| GW-30 | 3.5/4.0/5.0 | 3 | 5200×4910×3743 | 17.2 |
| GW-40 | 6200×4910×3743 | 19.5 |
| GW-50 | 4 | 7200×4960×3743 | twenty one |
| GW-3 | 1.1 | | | 3.43 |
| GW-5 | 1.1 | | | 5.5 |
Second, the cylinder type internal filter vacuum filter The inner surface of the cylinder of the cylindrical internal filter vacuum filter is its filtering surface. The slurry is fed to the inside of the cylinder, and the coarse material is deposited on the filter cloth before the particles due to gravity. A coarse particle layer with a large gap is formed, and as the fine particle material is deposited, a "bridging phenomenon" occurs in the pores, so that particles having a diameter smaller than the pores can be stopped, thereby improving the filtration effect. In the cake layer filtration, the main function of separation is the filter cake layer, not the filter medium. Therefore, when the filter type vacuum filter is formed into a filter cake, in addition to relying on the vacuum, the material can be settled by means of material sedimentation, and a high production capacity can be obtained by filtering the material elbow which is easy to settle. This is particularly suitable for the filtration of coarse-grained materials and magnetite which is particularly severe in magnetic agglomeration. In addition, the filter has a large filter cloth cleaning area, and the filter cake can be removed to have a longer cleaning room to restore the permeability of the filter cloth. [next]
The structure of the cylindrical internal filter type vacuum filter is shown in Figs. 3 and 4. The working principle is the same as that of the external filter vacuum filter. The inner filter surface of the internal vacuum filter is divided into a plurality of filter chambers, and the filter chamber is pumped and blown through a vacuum tube. The vacuum tube is connected to the dispensing head, and the dispensing head works in the same way as the external filter vacuum filter. The cylinder rotates for one week, and the circulation process of filtering, dehydrating, blowing, unloading, and cleaning the filter Ma Daha can also be completed, as shown in FIG. 5 .
Figure 3 barrel type internal filter vacuum filter (center tape unloading)
1, tape; 2, cylinder; 3, distribution head; 4, roller; 5, transmission
Figure 4 cylinder type internal filter vacuum filter (slot discharge)
1. Dispensing head; 2. Roller; 3. Unloading device; 4. Cylinder; 5. Transmission device
Figure 5 type internal filter vacuum filter working principle diagram
I, filtration zone; II, dewatering zone; III, discharge zone; IV, filter cloth cleaning zone
1, cylinder; 2, roller; 3, funnel; 4, belt conveyor; 5, filter cake; 6, pulp
There are two types of filter cake discharge methods for the cylindrical internal filter vacuum filter. One is to use a fixed chute with diabase lining to send the falling cake directly to the silo outside the silo. The discharging method is convenient to operate, the device structure is simple, and the multi-small filter is used; the other discharging method is the center belt conveyor discharging. This unloading method works reliably, and it is convenient for collecting belt conveyors and weighing scales when working in multiples.
The disadvantage of the cylindrical internal filter vacuum filter is that it is troublesome to replace the filter cloth, the body is large, and the working condition in the observation machine is inconvenient during operation.
The specifications, performance and technical parameters of the cylindrical internal filter vacuum filter produced in China are listed in Table 2.
Table 2 Performance of cylindrical internal filter vacuum filter
| model | Dimensions, length, width and height; mm | Filtration area m 2 | Cylinder speed, r/min | Cylinder drive power kW | Unloading method | Belt conveyor drive rate, kW | Weight t | |
| high speed | Medium speed | Low speed | |
| GN-8 GN-12 | 3200×3200×3400 3200×3200×3400 | 8 12 | 0.72 1.0 1.43 | 0.49 0.69 0.96 | 0.31 0.47 0.68 | 2.2 | Center belt conveyor or chute | 1.5 | 7 | |
| GN-20 | 5200×3900×4100 | 20 | 0.42 0.56 | | 0.12 0.17 | 3.5 | 2.2 | 13 14 | |
| Center belt conveyor | |
| GN-30 | 6300×3900×4100 | 30 | 0.84 1.04 | | 0.25 0.31 | 4.0 | |
| GN-40 | 6800×3900×4100 | 40 | 1.40 2.18 | | 0.42 0.66 | 5.0 | 3. |
