Mud pumps are divided into power end and power end. The following editor mainly introduces the mud pump accessories of these two major systems.
(a) Power end
1. The pump casing and pump cover are welded from steel plates. The bearing seats of the transmission shaft and crankshaft are integrally cast steel parts, which are welded to the pump casing after processing. After welding, they are annealed to eliminate residual stress.
2. The dimensions of the extended parts at both ends of the mud pump accessory transmission shaft are completely symmetrical, and large pulleys or sprockets can be installed at both ends. The supporting bearings at both ends adopt single row radial short cylindrical roller bearings.
3. The crankshaft adopts a forged straight shaft eccentric wheel structure, replacing the traditional three cylinder pump integral casting crankshaft structure at home and abroad. The casting is changed to a forging and the integral is changed to an assembly, which is convenient to use, easy to manufacture, and easy to maintain. The eccentric wheel, herringbone gear wheel hub, and shaft adopt interference fit.
4. The connecting rod of the mud pump accessory is made of ZG35CrMo, and the small end of the connecting rod is equipped with a pin shaft. Both ends of the pin shaft are equipped with single row centripetal short cylindrical roller bearings, which are assembled on the crosshead body. The crosshead body is made of ductile iron, and the guide plate is made of ductile iron. The gap between the guide plate and the crosshead is 0.26-0.38 meters, and the crosshead and intermediate rod are connected through flanges and bolts.
(b) Hydraulic end
1. Mud pump accessory valve box: The overall forging is a vertical structure with a clearance volume of only 7.3 liters, which is the drilling pump series with small clearance volume among high-power mud pumps in China. The three valve boxes are discharged and sucked in through the discharge and suction manifolds. One end of the exhaust manifold is equipped with a high-pressure four-way and exhaust pre compression airbag, and the other end is equipped with a lever type (single pin multi-point) shear safety valve.
The discharged pre compressed air bag is an integral casting with its body, capsule, and sealing ring. The inflation pressure of the pre compressed air bag capsule is 20-30% of the working pressure, but to ensure the long-lasting working performance of the capsule, it does not exceed 45.7 atmospheres (650psi). In this case, the pressure non-uniformity can be guaranteed to be ≤ 5%.
2. Mud pump accessories cylinder liner: Adopting bimetallic cylinder liner, the inner layer is made of high chromium wear-resistant alloy, and the internal surface roughness is required to be within 0.20, with an internal surface hardness of ≥ HRC60. The specifications of the cylinder liner are φ  100- φ  100 for users to choose from. The piston is composed of a piston core, pressure ring, and circlip, which meets ministerial standards. The intermediate mark is connected to the piston rod through a fixture for easy disassembly and assembly, and adopts an adjustable intermediate rod packaging box structure.
3. The cylinder head flange and valve cover flange are connected through trapezoidal threads.
4. Method for fixing the cylinder sleeve of mud pump accessories: The cylinder sleeve of the 3NB-600 pump is fastened and fixed with a movable joint.
5. Spray system: According to user requirements, a dedicated electric centrifugal pump or a centrifugal pump with a drive shaft is used as the spray pump, and the cylinder liner is cooled and lubricated through the nozzle on the spray box. Generally, water or water-based solution (soluble emulsified oil or diesel can be added) is used as the coolant, which flows into the water tank for recycling. According to water pollution procedures and water temperature (0 ℃
6. Mud pump accessory exhaust manifold assembly: Adopting an integral forged assembly and welded structure, the exhaust manifold and the front plane of the three valve boxes are connected with bolts and sealed with O-ring packing, and the exhaust valve cavities are not interconnected.