What is HDD machine Mud motor?
Mud motor is a down-hole tool, which used for HDD machine (horizontal directional drilling) method when the cutting action required for harder soils. Mud motors, convert hydraulic energy from drilling mud pumped from the surface to mechanical energy at the bit in the horizontal directional drill hole. In some Mud motors allows for bit rotation without drill string/rod rotation. In certain applications, compressed air, or other gas, can be used for mud motor input power. Normal rotation of the bit while using a mud motor can be from 60 rpm to over 100 rpm.
There are two basic types of mud motors; positive displacement and turbine. Positive displacement motors are typically used in HDD machine applications. Basically, a positive displacement mud motor consists of a spiral-shaped stator containing a sinusoidal shaped rotor. Mud flow through the stator imparts rotation to the rotor which is in turn connected through a linkage to the bit.
For horizontal directional drilling machine, a small bend angle is provided between the power section and the bearing assembly. This bend angle gives mud motors the ability to selectively drill curved or straight holes. Drill string/rods rotation produces a straight, slightly oversized hole. In the absence of drill string rotation, the hole curves in the direction of the bend
In some cases, a larger diameter wash pipe may be rotated concentrically over the non-rotating steerable drill string. This serves to prevent sticking of the steerable string and allows its tool face to be freely oriented. It also maintains the pilot hole if it becomes necessary to withdraw the steerable string.
Basically a mud motor is three part combination. Each and every part of it has its own working roles. Those three parts are
1] Orienting sub or housing sub, which connect mud motors power housing with the drill rods. It has an inner bore where the steering tool can be fitted.
2] Mud motors power housing, which consists of the rotor and stator; the transmission section, where the eccentric power from the rotor is transmitted as concentric power to the bit using a constant-velocity joint the bearing assembly which protects the tool from off bottom and on bottom pressures; and the bottom sub which connects the mud motor to the bit.
3] Drill bit, which cut the drilling hole. This is a rotating part.
A mud motor is described in terms of its number of stages, lobe ratio and external diameter. Stages are the number of full twists that the stator makes from one end to the other and the lobe ratio is the number of lobes on the stator, to the number of lobes on the rotor (the stator always has one more lobe than the rotor). A higher number of stages indicate a more powerful motor. A higher number of lobes indicate a higher torque output (for a given differential pressure), a lower number of lobes indicates a reduction in the torque produced but a faster bit rotation speed.
The operating parameters include flow rate, bit rpm and torque. The relationship between the rotor and the stator geometry determines the rotational speed and torque. The rotational speed is proportional to the flow rate and torque is proportional to the pressure drop in the fluid as it flows through the motor.
The use of mud motors is greatly dependent on financial efficiency. In straight vertical holes, the mud motor may be used solely for increased rate of penetration (ROP), or to minimize erosion and wear on the drill string, since the drill string does not need to be turned as fast.
For using a mud motor, the HDD machine should have more powerful mud pump and bigger drill rod inner diameter. With ZLCONN HDD machine you can get perfect HDD machine which can fit with various mud motors. We can also design and supply external mud pumps for more mud flow with our machine , so you can work easily even working in the hard rock condition.
To be continued:
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