Mud pump refers to the machinery that delivers mud or water and other flushing fluid to the borehole during drilling. Mud pump is an important part of drilling equipment.
Mud pump is commonly used in the positive circulation drilling, which is the surface flushing medium -- water, mud or polymer flushing fluid under a certain pressure, and through the high-pressure hose, faucet and drill stem center hole to send directly to the bottom of the drill bit, in order to cool the drill bit, remove the cuttings and transport them to the surface.
The commonly used mud pump is piston type or plunger type. The power machine drives the crankshaft of the pump to rotate. The mud pump crankshaft drives the piston or plunger to do reciprocating motion in the pump cylinder through the crosshead. Under the alternate action of suction and discharge valves, the purpose of pressing and circulating flushing liquid is realized.
The two main parameters of mud pump performance are displacement and pressure.
The discharge capacity is calculated as several liters per minute, which is related to the diameter of the borehole and the required velocity of the flushing liquid returning from the bottom of the borehole, i.e. the larger the aperture is, the larger the required discharge capacity is. It is required that the up return speed of the flushing fluid can wash the cuttings and rock powder cut by the bit away from the hole bottom in time and carry them to the surface reliably. In geological core drilling, the upward velocity is generally about 0.4-1.0m/min.
The pressure of the pump depends on the depth of the borehole, the resistance of the passage through which the flushing fluid passes and the nature of the flushing fluid delivered. The deeper the hole is drilled, the greater the pipe resistance and the higher the pressure required.
With the change of drilling diameter and depth, the displacement of pump can be adjusted at any time. A gearbox is arranged in the pump mechanism or its speed is adjusted by a hydraulic motor to achieve the purpose of changing the displacement. In order to accurately grasp the change of pump pressure and displacement, a flowmeter and a pressure gauge shall be installed on the mud pump, so that the drilling personnel can understand the operation / operation of the pump at any time, and judge whether the condition in the hole is normal through the change of pressure to prevent accidents in the hole.