NQ3, HQ3, PQ3 Series Latch Assembly | Core Barrel Spare Parts

Q3 series latch assembly is a core matching spare part for DCDMA standard triple-tube wireline core barrels, specially designed for NQ3, HQ3 and PQ3 triple-tube coring tools. It fits high-precision core sampling in broken rock formations, loose ground and easy-collapse boreholes. The complete integrated assembly features easy installation, high concentricity and stable core holding performance, serving as a key wear-resistant part to improve core recovery rate and prevent core loss in broken formations.
Three mainstream specifications are available: NQ3, HQ3 and PQ3, covering small-medium to large-diameter deep & ultra-deep wireline coring projects. It boasts strong versatility and fits all brands of Q3 triple-tube core barrels in the market.

Complete Product Composition
Each full Q3 latch assembly is a complete 5-piece set with fully matched components without extra fittings required:
* Latch Base: Load-bearing fixing base that ensures structural stability, uniform stress distribution and anti-deformation performance
* Core Latch: Key core holding component that elastically clamps rock core. It locks core while tripping and releases core during lowering for reliable core capture
* Latch Retaining Ring: Limiting protective structure to prevent core latch from slipping out, loosening or shifting and avoid core holding failure
* Centralizer Ring: Centering guide piece to reduce friction between inner and outer tubes, stabilize tool rotation and protect pipe bodies
* Seat Ring: Auxiliary positioning and pressure-bearing part that optimizes assembly clearance, absorbs vibration and extends overall service life

- NQ3 Latch Assembly: Dedicated for small-medium diameter triple tubes, applicable to shallow & medium boreholes, regular rock layers and slightly broken ground for geological investigation
- HQ3 Latch Assembly: Mainstream medium-large diameter model, suitable for medium-deep boreholes, alternating soft & hard rock and moderately broken formation coring
- PQ3 Latch Assembly: Heavy-duty large-diameter model for ultra-deep boreholes, heavily fractured rock, loose sandy soil and high-difficulty coring projects

1. Integrated Complete Assembly for Effortless Installation
All five components are pre-matched with standard clearance before delivery, featuring precise matching without on-site adjustment. Users can directly replace worn parts, greatly cutting disassembly & maintenance time for field operation.
2. Specialized for Broken Formations to Greatly Boost Core Recovery Rate
The Q3 triple-tube matching latch delivers wider clamping range and stable elasticity. It firmly locks core without core falling or slipping in fractured rock, weathered strata and loose sand layers where standard double-tube tools struggle with poor core recovery, significantly raising overall coring qualification rate.
3. High-strength Wear-resistant Alloy Material for Long Service Life
The critical core latch is precision-machined from spring alloy steel with integral heat treatment, maintaining lasting elasticity and resisting fracture. The base, retaining ring and centralizer ring are made of high-strength structural steel, resistant to mud erosion, high-speed friction and downhole collision, compatible with both clear water and mud drilling media.
4. DCDMA Standard Dimension for Universal Interchangeability Across All Brands
Manufactured strictly in accordance with international DCDMA drilling standards with precise dimensional tolerances. It perfectly matches NQ3/HQ3/PQ3 triple-tube wireline core barrels of all domestic and overseas brands with zero jamming or fitting deviation during replacement.
5. Dual Centralizing & Limiting Structure for Stable Operation
Equipped with combined centralizer ring and seat ring to effectively correct inner tube eccentricity, reduce swing and vibration and lower tool abrasion. Cooperated with retaining ring limiting design, it avoids core latch loosening failure and enhances construction safety downhole.