The screw propeller is a major component of the drilling fluid centrifuge. Its structure, materials and parameters are directly related to the separation effect, production capacity and service life of the drilling fluid centrifuge . As long as the function of the spiral is to push sediment, its requirements are different in the settlement area and the drying area. The solid particles in the suspension in the sedimentation zone gradually form a sedimentation zone toward the drum wall. The spiral should be conducive to moving the sedimentation without violently stirring up the sedimentation, causing the separated sedimentation and liquid phase to mix. In the drying zone, the spiral should not only continue to move the sediment, but also create favorable conditions for sediment and water separation.
The screw propeller is generally composed of a screw blade, an inner cylinder and a feeding chamber.
Spiral blades are components that directly contact the sediment to transport it. The common forms are:
A: Connected to the whole spiral blade, commonly used and easy to manufacture
B: Continuous ribbon-shaped spiral blades. The blades have poor rigidity and are not used much. They are mainly used for sedimentation and separation.
C: disconnected spiral blade
D: spiral blade with additional blades
Spiral is divided into single-headed and double-headed. Because double-headed spirals are easy to process and balance, they are mostly double-headed spirals.
There are two types of spiral blades. One is that the spiral blades are perpendicular to the drum busbar. This is convenient for welding and calibration. It is often used in design. One is that the blade is perpendicular to the axis of rotation.
Because the blade of the propeller directly contacts the sediment, the blade has high requirements on the material, and the blade needs to have high abrasion resistance. Generally, the surface of the blade is surfacing or spray-welded with cemented carbide, which is difficult to process. At present, a new process for manufacturing wear-resistant blades has appeared, which is characterized in that the wear-resistant sheet is fixed to the tile-shaped workpiece by brazing, welding or bonding, and then the two assembly is welded to the spiral blade, so that The centrifuge maintains a high production capacity.