Piston

Introduction of Piston

I. Structural Composition: The piston assembly typically consists of a piston core, rubber, retaining ring, pressure plate, and other components. The piston core is mostly forged from alloy steel such as 42CrMo, 45# steel, or 40Cr, while the piston rubber is usually made of nitrile rubber or polyurethane rubber.

II. Working Principle: The piston reciprocates linearly inside the cylinder liner. When the piston retracts, the volume inside the working chamber increases, reducing the pressure. Under external pressure, mud enters the working chamber through the suction valve, completing the liquid intake process. Conversely, when the piston advances, the volume inside the working chamber decreases, compressing the mud and raising the pressure. This forces the discharge valve open, expelling the mud and completing the liquid discharge process.

III. Common Types: There are mainly two types: assembled pistons and vulcanized integral pistons. Assembled pistons consist of multiple independent components such as the piston core, piston skirt, pressure plate, and retaining ring, which are assembled together. Vulcanized integral pistons directly vulcanizes and fixes the piston rubber onto the piston core.

IV. Material Characteristics: The piston made of nitrile rubber is suitable for general drilling environments with a working pressure below 20MPa and a working temperature not exceeding 120°C, offering excellent chemical resistance and wear resistance. The polyurethane rubber piston features superior oil resistance and wear resistance, capable of withstanding pressures below 35MPa, making it ideal for use in oil-based mud and high-sand-content environments.

V. Usage Precautions: Regularly inspect the piston for wear, damage, and leaks, and replace it promptly if any issues are detected.