Qestions in China slurry pump selection
China Slurry pump company - Do Pump specializes in the production of horizontal slurry pump, verticle slurry pump, submersible slurry pump, horizontal sand pumps, dredging pumps and submersible sand pumps. In this article, we will share the feedback of customers from Ivory Coast on the use of DO PUMP 12-inch horizontal sand pumps.
The life span of parts is sometimes only one month. Therefore, the use of correct information is a key factor in pump design. The main causes of wear are sliding erosion and particle impact. The wear of the slurry pump is generally severe.
Issues considered in hydraulic design and structural design
The flow rate of rotating parts and fluid should be kept low enough, a. Wear and hydraulic performance issues: in order to reduce wear. The thickness of the pump body cemented carbide lining or elastic lubrication material section should be increased to meet the needs of actual operation. The radial section of the impeller is generally close to a rectangle, and the front end seal is used on the vertical plane to reduce the axial rotation area. The pump casing is generally designed as a semi-spiral or ring shape, so that less wear is maintained in a wide range near the highest efficiency point the amount. When large solids need to be transported, the width of the built-in closed impeller is usually larger, and the number of blades is also reduced to 2-3. Under the premise of increasing the wear of the pump, the hydraulic performance of the pump will be reduced to varying degrees.
The volute structure of the slurry pump ranges from spiral volute to semi-spiral volute, in order to make the pump have the smallest amount of wear in the range of different working conditions with the highest efficiency flow. Then to the toroidal volute and the OB structure. The impeller types include the RV type with a rectangular radial cross section, the ME type with a twisted blade and a smooth rectangular cross section in the radial direction, and the most common HE type.
Different combinations of impeller and volute have different hydraulic performance and wear characteristics. Generally:
Has good hydraulic performance, 1.HE/T combination. But the wear performance is poor;
Has good hydraulic performance and wear performance; 2. ME/C combination.
It can be used in places with severe wear. 3. Different combinations of A or OB type volute and impeller.
For example, rubber, neoprene, polyurethane resin and other elastic materials, b. Data problem: impeller and volute material of slurry pump. Generally used in places where the impeller inlet speed is lower than 23m/, this can increase the effective cavitation margin of the pump.
c. Mechanical design (shaft, bearing, seal, pump body, etc.)
When using sliding thrust bearings under heavy loads, shafts and bearings must have higher strength, rigidity and reliability. Impellers connected by trapezoidal screws can generally accept heavy loads. Ball bearings are generally used in light load conditions.
Therefore, the allowable shaft deflection is larger than that of ordinary pumps, and the slurry pump has no radial seal. This will limit the life of the stuffing box and mechanical seal. Therefore, a shorter shaft is generally used, and the allowable deflection is also smaller, which can increase the life of the stuffing box. Generally, high-pressure water should be injected into the sealed cavity to dilute the material and extend the service life of the pump; if the material cannot be diluted, push-out seals can be used, generally used in single-stage slurry pumps, but the efficiency will be reduced by 3% .
At this time, the conveying fluid can be used for cooling; in some cases, the pump may be idling, and the mechanical seal generally adopts a partial balance structure. At this time, double mechanical seals must be used. Under light load conditions, general mechanical seals are used; under heavy load conditions, special mechanical seals must be used.
Can not accept large pressure loads, generally the strength of the pump casing made of elastic materials may be too small. Therefore, a layer of pump casing should be added, which is called a double-wall structure. The materials are generally hard metal, rubber or polyurethane resin. For large pumps, considering the volume and cost constraints, bolt fastening structures can be adopted.
d. The influence of solid particles on the centrifugal pump
The flow resistance loss of the conveying pipeline will slowly increase with the increase of the flow rate, and the flow-lift curve of the slurry pump changes more gently. The angle between the pipeline characteristic curve and the performance curve is very small, so that a small change in the head will cause a large change in the flow rate.
