Kinematic Transfer, Strike Velocity, and CFM Dynamics
Drill string penetration relies on matching a drill's internal bore stroke kinetics and valve cycling frequency with the rock mass deformation modulus.
Air Distribution Valving: Flapper vs. Rifle Bar Precision
Pneumatic drills experience severe energy attenuation when backpressure accumulates in the front cylinder head. SHENLI incorporates specialized flapper valve chests in the YT28 and YT29A units. Unlike standard rotary valves prone to micro-friction seizing, our directional steel flapper delivers instant port alternation, cutting kinetic drop at lower receiver pressures down to 0.45 MPa. This structural advantage gives mining crews sustained penetration in fractured gneiss where back-flushing air demand surges.
Flapper Valve Dynamics Anti-Seize Rifle Bar Torsional DurabilityPiston Stroke Geometry vs. Steel Fatigue
Penetration speed is not simply a function of raw force; excessive single-blow energy on brittle quartzite often induces premature rod fatigue and bit button pop-out. SHENLI's engineering balance pairs an 80–82 mm cylinder bore with a calibrated 60–70 mm stroke length. This ratio controls peak stress wave amplitude through H22 hex drill rods, protecting carbide tips while transferring over 75 Joules of net destructive fracture energy directly into the solid rock face.
Stress Wave Damping H22 Hex Compatibility Fatigue SuppressionMatching SHENLI Equipment to Specific Rock Formations
From dense plutonic granite intrusions to brittle sedimentary seams, choosing the correct SHENLI mechanism depends directly on compressive load thresholds, moisture conditions, and drift dimensions.
SHENLI YT29A Air-Leg Rock Drill
Engineered for dense plutonic granite, massive quartzite, and pyritic ore bodies with a Protodyakonov hardness scale of f = 12 to 18. Built for high-advance drift headings.
- Net Weight: 27.0 kg
- Cylinder Bore: 82 mm
- Air Consumption: ≤65 L/s (0.5 MPa)
- Drill Hole Range: Ø34 – Ø45 mm
Why it excels: The 82 mm bore produces exceptional percussion energy without stalling against high-torque rotational resistance in abrasive, fractured ground.
SHENLI YT28 Air-Leg Rock Drill
The benchmark choice for medium-to-hard rock strata (f = 8 to 14), such as skarn, basalt, and silicified limestone. Highly efficient in tunneling drifts up to 4.5 meters in height.
- Net Weight: 26.0 kg
- Piston Stroke: 60 mm
- Air Consumption: ≤52 L/s (0.5 MPa)
- Working Pressure: 0.4 – 0.63 MPa
Why it excels: Centralized control valve group located on the backhead provides intuitive handling while reducing overall air consumption by 15% compared to oversized equivalents.
SHENLI Y24 Handheld Rock Drill
Designed for downward vertical blast holes, secondary block benching, and dimensional stone quarrying in formations graded at f = 6 to 12.
- Net Weight: 24.0 kg
- Piston Stroke: 70 mm
- Impact Rate: ≥31 Hz
- Flushing Media: Air/Water Dual Path
Why it excels: The long-stroke 70 mm piston produces deep single-blow impact, preventing drill rod stick in vertical down-hole drilling where cuttings naturally build up.
SHENLI Y19A Handheld Rock Drill
Optimized for small-scale open quarrying, marble block splitting, and foundation bolt anchoring in softer sedimentary layers or thin-bedded sandstone (f = 4 to 8).
- Net Weight: 19.0 kg
- Impact Frequency: ≥34 Hz
- Air Hose ID: 19 mm
- Hole Depth Cap: Up to 3.0 m
Why it excels: Lightweight body reduces operator fatigue in elevated or tight working spots, maintaining smooth bit rotation without fracturing structural marble veins.
SHENLI G10 Pneumatic Breakers
Designed for soft stratum cutting, coal face extraction, roof brush trimming, and clay seam excavation where mechanical rotary drilling causes uncontrolled wall collapse (f = 1 to 4).
- Weight (G10/G20): 10.5 kg / 20.0 kg
- Impact Energy (G20): ≥60 J
- Percussion Rate: 16 – 20 Hz
- Shank Retainer: Heavy Helical Spring
Why it excels: High single-stroke chisel impact breaks brittle material cleanly along natural bedding planes without creating fine airborne dust clouds.
SHENLI B87C Heavy Paving Breaker
A powerhouse tool for reinforced concrete demolition, trench rock ditching, and secondary breaking of oversized igneous boulders in open-pit drop yards.
- Net Weight: 39.0 kg
- Bore Diameter: 63.5 mm
- Stroke Length: 146 mm
- Percussion Energy: ≥100 J
Why it excels: Long piston travel combined with a massive 39 kg deadweight converts line pressure into over 100 Joules of pure down-hole impact force.
SHENLI Technical Parameter Comparison
Direct comparative matrix across mass, consumption, stroke parameters, and recommended geological strata.
| Model | Type | Operating Mass | Cylinder Bore | Piston Stroke | Air Consumption | Impact Energy | Shank Size | Optimal Ground Hardness |
|---|---|---|---|---|---|---|---|---|
| YT29A | Air-Leg Jackleg | 27.0 kg | 82 mm | 60 mm | ≤65 L/s @ 0.5MPa | ≥78 J | Hex 22 × 108 mm | f = 10 – 18 (Granite, Quartzite) |
| YT28 | Air-Leg Jackleg | 26.0 kg | 80 mm | 60 mm | ≤52 L/s @ 0.5MPa | ≥70 J | Hex 22 × 108 mm | f = 8 – 14 (Limestone, Skarn) |
| YT24 | Air-Leg Jackleg | 24.0 kg | 70 mm | 70 mm | ≤45 L/s @ 0.5MPa | ≥65 J | Hex 22 × 108 mm | f = 6 – 12 (Metamorphic Rock) |
| Y24 | Handheld Rock Drill | 24.0 kg | 70 mm | 70 mm | ≤40 L/s @ 0.5MPa | ≥60 J | Hex 22 × 108 mm | f = 6 – 12 (Bench Down-drilling) |
| Y19A | Handheld Rock Drill | 19.0 kg | 65 mm | 54 mm | ≤32 L/s @ 0.45MPa | ≥42 J | Hex 22 × 108 mm | f = 4 – 8 (Marble, Soft Sandstone) |
| G10 | Pneumatic Chisel Pick | 10.5 kg | 38 mm | 155 mm | ≤20 L/s @ 0.4MPa | ≥30 J | Ø24 × 70 mm | f = 1 – 3 (Coal, Soft Shale, Clay) |
| B87C | Heavy Paving Breaker | 39.0 kg | 63.5 mm | 146 mm | ≤36 L/s @ 0.5MPa | ≥100 J | Hex 32 × 152 mm | f = 4 – 10 (Secondary Concrete/Basalt) |
On-Site Empirical Performance Case Studies
Detailed operational feedback and advance rate data collected across global extraction sites using SHENLI equipment.
Leg Support: FT160BD Telescopic
Compressor Delivery: 22 m³/min @ 0.62 MPa
High-Hardness Sub-level Drift Heading Optimization
In an underground gold extraction drift with extreme silica content and heavy quartz veining, standard 76 mm piston units suffered constant bit stalls and valve fluttering. Upgrading the fleet to SHENLI YT29A drills boosted penetration speed by 28%. The heavier 82 mm piston diameter maintained full torque across deep 2.4-meter blast holes, eliminating rod binding near the drift perimeter.
Drilling Orientation: Vertical Split Line
Hole Pattern: Ø32 mm @ 200 mm Spacing
Preserving Block Quality in Premium Calcite Marble
High-energy pneumatic drills often generate micro-fractures radiating from blast and wedge splitting holes, ruining high-value marble blocks. Switching to lightweight SHENLI Y19A sinkers gave quarry teams precise, controlled penetration without internal stress shock. The balanced 34 Hz percussion rate produced exceptionally clean, straight holes across 1.8-meter cuts, protecting decorative stone veins.
Pneumatic Supply Optimization and Preventive Care
Maximizing SHENLI equipment lifespan and penetration rates requires precise lubrication rates and clean air supply lines free of dynamic pressure drops.
Inline Lubrication Control (FY200B)
Always pair SHENLI jackleg drills with an automatic inline oiler like the FY200B (200 ml capacity). Calibrate the needle valve to deliver 2.5 to 3.0 ml of rock drill oil per minute. Running with dry air causes fast galling on piston strike faces and rifle nut splines within 40 operating hours.
Pressure Line Maintenance
Keep gauge working pressure between 0.50 and 0.63 MPa right at the tool intake. Running below 0.40 MPa lowers strike energy by roughly 35% and increases drill steel jamming. Use a minimum 25 mm (1-inch) high-pressure air hose for runs over 30 meters from the manifold to prevent line drop.
Abrasive Dust & Water Flushing
In wet underground drilling, always turn on central water flushing (0.3–0.4 MPa water line) before engaging percussion. When finishing a shift, run dry air through the machine for 30 seconds to blow out moisture and coat moving internal parts with lubricating oil, stopping internal cylinder corrosion.
Selecting the Ideal SHENLI Package for Your Mining Plan
Balance production output, compressor fleet capacity, and spare parts interchangeability across your mining operations.
Underground Development Package
Target Operations: Hard rock drift headings, decline tunneling, and vein cross-cuts in solid igneous/metamorphic formations.
- Primary Drilling Rig: SHENLI YT29A / YT28
- Feed Mechanism: FT160BD Long Retractable Pusher Leg
- Lubrication Unit: FY200B Automatic Oiler
- Steel Profile: H22 Hexagonal Hollow Drill Rods
- Drill Bits: Ø38 – Ø42 mm Tungsten Carbide 7-Button Bits
Quarry & Open-Pit Benching Package
Target Operations: Secondary boulder breaking, dimensional block splitting, and down-hole bench blasting in surface quarries.
- Handheld Sinker Drill: SHENLI Y24 / Y19A
- Heavy Impact Breaker: SHENLI B87C (Secondary Fracturing)
- Air Supply Sizing: 7.5–11 m³/min Portable Diesel Screw Compressor
- Chisel Type: Moil Point & Narrow Chisel Shanks
- Recommended Flushing: Dry High-Pressure Air Blow System
