The mud pump is the key device in the drilling fluid circulation system. It is used to deliver drilling fluid to the bottom hole under pressure to cool the drill bit, carry cuttings and protect the wellbore wall.Mud pump is a reciprocating pump, its principle of action and the general reciprocating pump completely the same.
First, the structure and working principle
The working principle of the horizontal single-bar single-acting reciprocating pump is consisted of two parts: the drive (power end) unit and the hydraulic (hydraulic end) unit.
When working, the power machine drives the spindle and the crank fixed on it to rotate through belt, drive shaft, gear and other transmission parts.When crank rotates counterclockwise from horizontal position from left to right, the piston moved to the power end, the pressure in the cylinder decreases and forming a vacuum, pool drawn into the liquid in the role of liquid surface pressure, open the suction valve in hydraulic cylinder, until a piston moves to the right point, the working process is called pump suction process.Crank after finished the suction process, to continue rotating along the counter-clockwise, then piston began to move to hydraulic end , liquid in the cylinder pressure is squeezed, suction valve closed, the discharge valve is opened, the liquid into the discharge pipe, until the piston movement to the left end point, the working process is called pump discharge process.With the continuous operation of the power machine, the reciprocating pump continues to repeat the suction and discharge process, and the liquid in the pool will continue to flow through the discharge pipe to the bottom of the well.
The distance the piston moves in the cylinder is called the piston stroke.The number of reciprocations per minute of the piston is called the number of plunges of the piston.
Two, mud pump classification
There are many kinds of mud pumps, and the classification method is different, which can be summarized into the following types:
(1) according to the number of cylinders, it is divided into two cylinders and three cylinders.
(2) according to a piston in the liquid cylinder reciprocating inhalation or discharge of liquid times, liquid absorption or drainage once called single-acting pump, liquid absorption or drainage twice called double-acting pump.
(3) according to the arrangement mode and mutual position of the cylinder, there are horizontal pump, vertical pump, v-shaped pump and star pump, etc.
(4) according to the piston style divided into piston pump, plunger pump, etc.
As the liquid delivered by mud pump is usually drilling fluid, it is also called mud pump as drilling pump. At present, mud pump used in the construction of water drilling rig is mainly horizontal piston pump with three cylinders and two cylinders, and vertical pump.
