High-Performance 3 1/2-Inch External Spiral PDM Motor for Coal Mining Drilling

Product Introduction

Engineered for rigorous underground coal mine directional drilling, this 3 1/2-inch outer diameter positive displacement mud motor (PDM) converts the hydraulic energy of drilling fluid into steady mechanical torque. The equipment features a heavy-duty fixed 1.25° bent housing and industry-standard 2 7/8 REG connections at both ends, ensuring precise integration with various bottom hole assembly (BHA) configurations and measurement while drilling (MWD) systems. This standardization allows for rapid interchangeability of wear parts across global operations, minimizing downtime.

The core mechanism relies on a meticulously calibrated 7:8 lobe rotor-stator ratio. This specific configuration excels at delivering powerful, consistent torque at lower rotational speeds, perfectly matching the demands of penetrating hard rock formations in coal seams. Touching the internal components reveals the cold, heavy-duty feel of the high-strength alloy steel rotor, which undergoes a dual-layer chrome polishing process to create a remarkably smooth, friction-reducing surface. Paired with a temperature-resilient, dense rubber stator, this construction significantly extends operational lifespan even when exposed to abrasive drilling fluids. The compact architecture not only facilitates precise well trajectory control but also minimizes non-productive time during gas drainage, water exploration, and geological probing.

Product Advantage

Xinyongjia hydraulic downhole mud motors have obtained official API international certification. Key advantages of our coal mine downhole mud motors are listed below:

1.This positive displacement mud motor takes clean water as driving medium, suitable for water-based drilling operation of underground coal mine PDM drilling motor without complex mud circulation system.

2.Equipped with professional triple anti-drop assembly, the coal mine downhole mud motor greatly lifts safety coefficient during underground drilling and avoids falling accidents in boreholes.

3.Our hydraulic PDM drilling motor adopts heavy-duty durable drilling configuration, which extends service life and delivers stable performance in tough coal seam drilling environments.

Product Advantage

4.The outer contour of this downhole mud motor supports optional slick surface, spiral design or spiral structure with three straight blades to satisfy diverse coal mine borehole drilling demands.

5.Customers can select non-magnetic material or high-strength alloy steel for the coal mine screw motor to fit various complex underground coal mine drilling working conditions.

Technical Parameters

Product Uses

Application Scenarios of Xinyongjia 5LZ73X7.0-5 Hydraulic Steel Screw Motor

1. Coal Mine Gas Drainage Drilling

   The compact 89mm outer diameter allows this mud motor to maneuver through restricted underground mine tunnels with ease. It delivers the consistent torque required for drilling horizontal boreholes, facilitating efficient coalbed methane extraction and the construction of critical gas drainage networks.

2. Coal Mine Roadway & Side Drilling

   When reinforcing mine roadways, space is often severely limited. This miniature hydraulic screw motor is engineered for sidetracking and branch hole drilling within confined coal rock layers. Its precise directional control accelerates construction cycles for structural reinforcement.

3. Coalfield Geological Exploration Drilling

   Geological surveys demand reliable power when transitioning between mixed coal and rock formations. The motor's 7:8 lobe profile ensures a stable mechanical output that prevents stalling during short-distance directional exploration, providing accurate geological probing data.

Product Operate Guide

To maintain the optimal rate of penetration (ROP) during challenging coal seam drilling, field engineers must continuously monitor the motor's differential pressure. A sudden spike in operating pressure often indicates an impending stall condition, requiring an immediate reduction of weight on bit (WOB) to prevent mechanical damage. Conversely, gradual pressure losses over an extended period may signal normal stator rubber wear. We strongly recommend maintaining the drilling fluid flow rate strictly between 360 and 712 liters per minute to prevent premature degradation of the internal elastomer profile. For comprehensive troubleshooting protocols—including diagnosing rotor-stator interference, resolving low-torque outputs, and scheduling preventative maintenance—please refer to our complete operational documentation provided below. Proper adherence to these guidelines ensures extended equipment lifespan and reliable directional control.

Xinyongjia Downhole Motor Manual(Chinese -English)

Download