Piston Diaphragm Slurry Pump

In piston diaphragm pumps, the crankshaft is the core transmission component that converts rotary motion into reciprocating motion, enabling indirect actuation of the piston–diaphragm assembly while isolating the process fluid from the drive mechanism.

The main parts of a three-cylinder single-acting power end include a crankshaft, power end case, cross-head, connecting rod, and joint rod as well as bearing

The power end adopts two support structures, it is the frame that carries the crankshaft and cross-head for normal operation, and the piston cylinder is also fixed on the power end case. The piston thrust on the diaphragm and the crankshaft by the reaction force of the connecting rod are absorbed by the power end unit. This requires the power end box to have high strength and impact resistance,

Structure Introduction:

The power end housing is a one-piece casting structure. The crankshaft and the box body adopt two support structures, which greatly simplifies the maintenance work of the power end. The bearing cover and seat are connected with dynamic load pre-stressing studs. The thread of the stud is milled, and the mechanical property reaches 10.9 grade with reliable strength.                                                                                      

Technical advantages:

1. Compared with the structural part box, the cast box is suitable for mass production, and the production quality and production cycle can be easily guaranteed.
2. The ductile iron of the same grade as the wind power booster box body is chosen as the material of the power end box body.
3. The casting box body of ductile iron material has sufficient rigidity, shock, and impact resistance, which can prevent deformation and ensure transmission quality.
4. Cast box body of ductile iron material has almost no internal stress during the casting process, and simple aging treatment can eliminate the internal stress.
5. Compared with the welded box, the casting box does not have any welding work, which fundamentally avoids the contradiction between quality control and production cycle and manufacturing cost caused by a large amount of welding work.

In short, the cast power end box is better than the welded box in several aspects, such as seismic resistance, impact resistance, the concentration of internal stress, quality control, production cycle, and cost contradiction.

Crankshaft Structure Introduction:

The crankshaft adopts a three-inflection, two-support structure, manufactured by one-piece forging and molding.
It consists of the input end, three crank throws, and two orthocentric shafts, forming a compact and mechanically stable transmission structure.

Technical Advantages:

1. Two-Support Structure at Both Ends

Heavy Pump has reasonably allocated the crankshaft bearing clearances, forming a support layout in which:

• Both ends provide primary support
• The middle support plays a supplementary role

This design effectively avoids the static instability issues caused by four-support structures.
At the same time, crankshaft deflection is controlled within the allowable design range, resulting in:

• Stable force distribution
• Reliable power transmission
• Complementary interaction between strong and weak supports

Overall, the system achieves high operational stability under continuous heavy-duty conditions.

2. High-Strength Electroslag Remelting Alloy Steel Crankshaft

The crankshaft is made of high-strength electroslag remelting (ESR) alloy steel, which offers significant material advantages:

• No defects such as shrinkage cavities, looseness, inclusion aggregation, or macroscopic segregation
• High structural density and uniform composition
• Low impurity content and consistent mechanical properties

These characteristics are especially critical for process industries with high continuous operation requirements, such as tailings handling and heavy-duty pumping applications.

3. Optimized Connecting Rod Bearing Clearance Control

The connecting rod bearings adopt precise clearance control technology, which effectively:

• • Reduces impact loads on the bearings during operation
  • Improves bearing service life
  • Enhances overall operational smoothness and reliability