The SD220L Crawler full hydraulic pump reverse circulation drilling rig is mainly used for drilling vertical pile foundations in large-diameter, pebble, hard rock and other complex strata. With the advantages of fast footage and high automation, it is widely used in the drilling construction of pile foundations in ports, wharfs, bridges in rivers, lakes and seas, significantly saving labor and construction costs.

Main Structure and Performance Characteristics

Main Structure

• The equipment adopts a crawler chassis. The hydraulic system, composed of an engine and hydraulic pump installed at the rear of the vehicle, drives the motor reducer to realize self-propelled functionality.
• Four hydraulic jacks are installed on the front and rear sides of the track chassis. The main machine can be supported and adjusted to front, rear, left, and right levels without leveling the construction site ground. The jacks can be opened and closed freely under separate control. During construction, the hydraulic jacks are extended, allowing the maximum width of the outrigger fulcrums to reach 3.8m.
• The gantry of the drilling rig is fixed at the front end of the chassis platform and placed vertically in its working state.
• The gantry frame and the lower door-opening frame feature an integrated structure, which greatly enhances the stability of the overall frame structure.
• A gantry subframe is installed inside the gantry, increasing guide performance, stabilizing construction, and greatly prolonging the service life of the drill pipe. The power head is installed inside the lower end of the gantry subframe. The hydraulic cylinder used for lifting the power head (including the subframe) is installed inside the square tube of the subframe's mullion.
• The rotary head adopts a rotary drilling rig head to increase output torque, driven by three 107 variable motors.
• The right mullion of the gantry is equipped with a manipulator and a cantilever crane (composed of a hydraulic winch, cantilever, pulley, etc.) used for disassembling and assembling drill pipes.
• Close to the rear of the gantry, the middle and front part of the platform is equipped with an air-conditioned cab containing an operation console and display screen.
• Behind the cab and in the middle of the platform, a slurry pump is installed. The slurry pump is directly driven by a 90kw motor, avoiding the energy loss of electric-to-hydraulic conversion while reducing construction costs.
• In the hydraulic pump station at the rear of the platform, two independent hydraulic systems are installed:

  10.1 Travel Hydraulic System: Composed of a Cummins 197kw diesel engine and negative flow constant power variable pump. It is used for the travel motor, main engine outrigger cylinder, door opening frame outrigger cylinder, lifting cylinder, and other actuating elements to facilitate site movement and pile hole alignment.

  10.2 Rotary Head Hydraulic System: Composed of a 132kw three-phase asynchronous motor and negative flow constant power variable pump. It is used for rotary head operation, lifting oil cylinders, manipulator oil cylinders, hydraulic winches, and other actuating elements.

• The advanced hydraulic system is specially designed for pump suction reverse circulation. Main components such as the main pump, rotary head motor, main valve, and load-sensitive auxiliary valve are sourced from well-known domestic and international brands (including Rexroth, Kawasaki, HC, Hengli, and Changjiang Hydraulic) to ensure stable performance.
• Key electrical control components (display and controller) are high-end original imports from internationally famous brands. The control box adopts reliable aviation grounding and plug connections, creating a specialized electrical control system optimized for pump suction reverse circulation drilling.
• The switchboard is installed behind the two hydraulic pump stations and is enclosed under protective covers.
• Placing the mud pump on the platform reduces the distance between the mud pump and the water surface of the pile hole. This shortens the suction lift, greatly improving the mud pump's working performance.
• Drill Pipe Specification: ￠325x25x2000. Features threaded connections for convenient automatic assembly/disassembly. The buckle heads and nuts at both ends are taper rectangular buckles made of quenched and tempered 35CrMo, while the pipe body is made of 16Mn. Preheating before welding and heat preservation after welding processes are used to ensure welding quality and extend service life.
• Drilling Accessories: Utilizes rotary drilling tools. Recommended accessories depend on geological conditions, including two-wing, three-wing, and four-wing rotary drilling tools, as well as cylindrical rotary tools. Teeth classifications include scraper-type alloy teeth, roller teeth, and cutter teeth.

Performance Characteristics

• Advanced Slurry Pump: Designed by water conservancy experts. The double-channel impeller offers high working efficiency and energy-saving effects. Pump casing and impellers are made of wear-resistant high-chromium iron via investment casting. The impeller undergoes dynamic balance testing to support high balance and fast speeds. Solid particles, rock blocks, and pebbles smaller than the drill pipe's inner diameter can be discharged without repeated crushing, leading to high slag removal efficiency.
• High Torque & Lifting Force: Specifically designed to handle complex geologies such as gravel, pebble, and hard rock.
• Integrated Manipulator & Winch: Arranged on the gantry frame to make drill pipe removal and installation convenient, reliable, and labor-saving.
• Smart Rotary Head: Delivers constant power output with automatic transmission. The variable motor automatically adjusts output torque and speed depending on geological conditions for fast, automated footage and high construction efficiency.
• Real-time Monitoring: The cab display screen monitors and displays operational data for each system, keeping the operator fully informed of machine status.

Technical Specifications

Project Process Scheme

The pump suction reverse circulation drilling rig utilizes water circulation to continuously transport cutting materials from the pile hole to an adjacent mud pit. Sand, stone, and other granular materials settle to the bottom of the pit, while the clarified mud flows back into the pile hole to maintain the required water level. The specific process scheme operates as follows: