How to choose dry mortar mixer machine and production line

At present, the dry powder materials used  in building materials mainly include two kinds of dry powder mortar and putty powder. Inorganic perlite insulation and thermal insulation mortar also belong to the category of dry powder mortar. The main method of these materials in the production is to mix and stir. Such materials as cement, drying sand, fly ash, rubber powder, cellulose, polystyrene particles, etc. are uniformly mixed in a certain proportion, so how to choose a dry powder mixer in the production of putty powder and dry mortar?

Few years ago, many putty powder manufacturers used vertical dry powder mixers considering from the aspect of cost. The raw materials were manually poured into the mixer and conveyed to the mixing bag by screw. Various raw materials were mixed together. There are three obvious disadvantages of the vertical dry powder mixer:

Obvious disadvantages of the vertical dry mortar mixer

• The mixing uniformity is not good; the putty powder and dry powder mortar require high uniformity, because most of the active ingredients are small qty polymer powder, cellulose, etc., and these small qty chemical addtive components in the finished product have a ratio of only one thousandth or evenless, therefore, the uniformity of the finished product is directly related to the quality of the product. The uniformity of the vertical mixer is acceptable when producing putty powder, but the specific gravity of cement and sand is quite different when producing dry mortar. It is easier to happen mixing uneven.

• The residual amount is too large caused unevenness between each batch of materials. The working principle of the vertical mixer is that the vertical spiral rotates at a high speed, and the material is lifted from the bottom to the top, and then gradually mixed in a diffuse manner after passing through the bulk plate. The high-speed rotation of the spiral makes the components with larger specific gravity such as quartz sand and other materials thrown far away from the axis because of the large centrifugal force and cannot participate in the mixing. On the other hand, the side clearance of the spiral is large, generally 4-5 mm or even larger, and the vertical spiral side clearance is up to 10 mm, so each batch of materials will not be completely removed, and there will be a large residue. Due to inaccurate operating procedures, the residues of each batch of materials are different which directly affects the content of various components in the next batch of materials, resulting in unevenness between each batch of materials. The key is: the less the added amount of raw materials, the more expensive the raw materials, the price is around thousands of USD a ton, so you can imagine the great loss.

• The maintenance rate is too high; the bearings of the vertical dry powder mixer are located at the upper and lower ends, and the lower bearing will contact the material, which will easily cause the sudden death and damage of the bearing. The bearing needs to be replaced regularly, and the maintenance rate is very high.

With increasingly fierce competition today, once unqualified products flow to the market, more or less quality problems will occur during construction, such as indoor paint cracking, hollowing, poor scratching, etc., outdoor protective layer and tile hollowing off, It is even blown off by strong winds, rainwater seeps through the cracks to the outer wall surface, and the fire resistance level is low and easy to age. Therefore, the quality of products restricts the sales. Recommendations-In addition to checking the rationality of the formula and the quality of various raw materials, whether the choice of the mixer is reasonable is a matter of concern. So what kind of dry powder mixer should I choose?

What type dry mortar mixer machine and production line should I choose

• Horizontal dry powder mixer has become the first choice at present. There are two series of horizontal spiral ribbon mixer and twin shafts non gravity mixer according to the mixing structure. The appearance of ribbon mixers is cylindrical and the material is carried through the multi-layer spiral in the cylinder.  Multi-layer spiral ribbon design, outer spiral ribbon narrow inner spiral wider, the direction of two adjacent spiral ribbons is reverse design. During the flow of materials in the cylinder, multiple material flowing direction are formed, interpenetrating, displacing and mixing repeatedly. The wall of the tumbling mixing cylinder on both sides has no block and dead angle, which is an ideal choice for mixing.

• However, the more efficient dual-shaft zero-gravity mixer is widely used in the complete automatic production line pursuing large output: the horizontal dual-shaft paddle mixer has faster mixing speed, good mixing quality, wide application range, and large-scale external insulation materials and dry powder coatings manufacturers normally choose this type mixer. The material in the mixing machine is subjected to the action of two oppositely rotating rotors and undergoes a compound movement. On the one hand, the blade with animal material rotates counterclockwise along the inner arm of the machine slot, and on the other hand, it turns the animal material left and right. At the intersection of the two rotors, it becomes a weightless zone. In this area, no matter the shape, size and density of the material, It can make the material float in a state of instantaneous weightlessness, which makes the material form an all-round continuous cyclic turning in the mixer tank, interlacing and shearing each other so as to achieve the rapid, soft and uniform mixing.

  
  

  
  

  
  

  
  

The material particles in the machine have circular motion and axial motion under the blades; according to the state of material mixing motion, there are convection mixing, shear mixing and diffusion mixing.

Different mixing process

Convective mixing;

the materials in the two shaft areas will flow in the axial direction respectively. After reaching the shaft end, due to the action of a set of small-angle blades at the shaft end, the material turns to the other shaft area to move, so that the material in the entire machine forms a horizontal plane. Circulating flow; on the other hand, the materials in the two shaft areas will rotate around their respective axes at the same time, and each shaft area forms a vertical surface and circulating material flow; and the materials at the junction of the two shaft areas also flow transversely to the other shaft area. Because of this multi-directional compound circulation convection, the materials in the machine will move and mix from one place to another more quickly.

Shearing and mixing: 

The materials form shearing surfaces with each other under the action of the blades, and the masses or particles of the materials slide and collide with each other to form shearing and mixing.

Diffusion mixing; 

the diffusion mixing exists in the entire machine, but it is more pronounced in the area near the center line of the machine, because the two rotors rotate in opposite directions and there is an overlapping area in the motion of the blades in the machine, which makes the area near the center line the material is affected by the rotating blade. The material turned by the blade in this area is scattered in the air due to inertia at the moment it leaves the blade. During the scattering process, the material friction and penetrate each other, forming a fluidized area near the centerline of the machine. Each particle can move freely in the fluidized area, and the material particles are fully diffused and mixed in the free movement. The friction in this area is small, the mixing is light and gentle, and there is no segregation in the mixing. Especially when the particulate material is in the fluid state, the diffusion and mixing effect is better. The formation of the fluidized zone, coupled with the effects of convection mixing and shear mixing, makes the mixing speed of the biaxial blade mixer faster than the general mixer and the mixing uniformity is high.

All in all, as horizontal dry powder mixers have become popular oday, it is a wise choice to choose different horizontal dry powder mixers according to their needs and output.  For more questions, please consult Ant Constructions engineer or visit antdrymix.com

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