Steel pipe internal shot blasting machine
To meet the requirements for shot blasting the inner walls of steel pipes, this design incorporates a mobile, hydraulically driven shot-blasting unit specifically for pipe interiors, a stationary abrasive circulation system, a mobile hydraulic pump station with an abrasive supply system, mobile front and stationary rear shot-blasting chambers, a two-stage "inertia plus filter bag" dust collection system, and a Siemens electrical control system, thereby ensuring high production efficiency, a high degree of automation, and smooth, reliable operation.
A. Equipment Composition
The machine consists of the following nine major functional systems and components:
(1) High-performance wear-resistant materials: Investment-cast wear parts and SP high-manganese steel liners.
(2) Shot blasting and cleaning system (abrasive circulation): Hydraulic internal-wall shot blasting unit, support rollers for the blasting unit, rotating pipe transport carriage, belt-type abrasive feeder, abrasive flow controller, abrasive/debris separator, bucket elevator, abrasive return belt conveyor, screw conveyor (1 unit), mobile blasting chamber, stationary blasting chamber, and platforms, ladders, and guardrails.
(3) Hydraulic system: Closed-loop hydraulic control system for the internal blasting head.
(4) Pneumatic system: Pneumatic cylinders, pneumatic valves, air treatment units (FRL assemblies), etc.
(5) Electrical system: Siemens PLC, variable frequency drives (VFDs), sensors/detection components, control cabinet, operator console, cables, etc.
B. Process Flow
· Workpiece cleaning sequence:
The steel pipe is placed onto the rotating rollers of the mobile rotating carriage via the lifting and lowering action of a swing arm (positioned at the internal shot blasting station) → The mobile rotating carriage advances to feed the pipe into the fixed shot blasting chamber and seals the front end → The mobile shot blasting chamber advances to seal the rear end → A hydraulic shot blasting trolley drives the internal blast head into the pipe to perform cleaning. Upon completion of descaling, all moving components return to their initial positions.
· Abrasive circulation sequence:
Abrasive storage → Flow control → Belt-based abrasive feed → Shot blasting → Pneumatic transport of abrasive to the fixed shot blasting chamber → Belt return of abrasive → Screw conveyor → Bucket elevator → Abrasive/debris separator → Abrasive storage hopper (recirculation).
· Dust treatment sequence:
1. Shot blasting chamber dust → Airflow control → Inertial dust collector → Bag-type dust collector → Fan → Discharge to atmosphere.
2. Abrasive/debris separator dust → Airflow control → Cartridge-type dust collector → Fan → Discharge to atmosphere.
C. Machine Structure, Principles, and Features (Including High-Performance Wear-Resistant Materials)
1. High-Performance Wear-Resistant Materials
To address the primary challenge facing shot blasting equipment—wear life—our company has developed and introduced high-performance wear-resistant materials, thereby narrowing the quality gap between domestic and international equipment technologies:
· Wear-Resistant Parts for the Shot Blasting Unit
The key consumable parts of our shot blasting unit (blades, shot distributors, and control cages) are manufactured using high-wear-resistance alloys and precision investment casting processes. The castings feature directional solidification and are free from mechanical defects such as shrinkage porosity, shrinkage cavities, gas holes, and sand inclusions; their service life is 5–10 times that of conventional wear-resistant materials.
(1) Blades (high-wear-resistance alloy): Average service life > 2,000 hours.
(2) Shot distributors and control cages (high-wear-resistance alloy): Average service life > 2,000 hours.
· Wear-Resistant Parts for the Shot Blasting Chamber: The chamber liners are made of rolled SP high-manganese steel; their service life is 10–15 times that of conventional wear-resistant materials, with an average service life of ≥ 25,000 hours.
· Shot Blasting Impeller: The impeller is made of a special alloy subjected to carburizing treatment—average service life > 7,500 hours.
2. Hydraulic Shot Blasting Head
This machine features a novel, high-efficiency, hydraulically driven internal shot blasting head designed based on technology from the Dutch company BL. To minimize the unit's size—enabling it to enter the interior of steel pipes—a hydraulic drive system was selected. The unit comprises the following main components: a hydraulic drive system, the shot blasting assembly, and a roller support structure.
Two internal shot blasting head systems are included in this configuration:
Model HSGN50JD (Large): for processing steel pipes with diameters of φ762–φ1020 mm.
Model HSGN35JD (Small): for processing steel pipes with diameters of φ356–φ711 mm.
3. Roller Support Mechanism
As the shot blasting head must travel along the interior of the steel pipe during operation, it is equipped with a roller support mechanism. This mechanism bears against the inner wall of the pipe, allowing the head to travel longitudinally and rotate radially, thereby ensuring smooth and reliable movement.
4. Abrasive Control System
The abrasive control system consists of an abrasive flow controller and an abrasive delivery pipe.
The abrasive flow controller utilizes pneumatic abrasive supply technology from the US-based company Wheelabrator, featuring lead-screw adjustment and pneumatic opening/closing. It is primarily composed of a sector gate, a housing, transmission components, and a pneumatic cylinder.
This machine is equipped with the HAI Ocean Surge® direct-coupled high-efficiency blast wheel (German design with independent patents, Patent No.: ZL 2015 2 0702933.5).
The blast wheel is the heart of a shot blasting machine, and its design determines the performance of the entire system. The HAI Pengpai® blast wheel comes as standard equipment, delivering superior blasting performance. Available in a variety of sizes and materials, the H-series blast wheel ensures flexibility across diverse manufacturing processes. Its key advantages include enhanced blasting performance, reduced abrasive consumption, significantly extended equipment uptime, and effective noise reduction.The casing is lined with curved, multi-layer labyrinth-style sealing plates; the hot zone features a thickness of 70mm, ensuring excellent sealing performance and a uniform distribution of the projected abrasive media over an expanded coverage area. The internal design allows for the adjustment of abrasive trajectories, thereby enhancing blasting efficiency and minimizing self-wear. Additionally, a specialized dynamic design boosts efficiency by 30% compared to standard blast wheels.
Selected Cases of KEEJOO Roller Conveyor Steel Shot Blasting Machine
245 sets of section steel shot blasting machines manufactured for Hangxiao Steel Structure Company
16 sets of section steel shot blasting machines manufactured for Hangzhou Southeast Grid
Shanghai Guandar steel profiled steel roller conveyor shot blasting machine 2 sets
9 sets of section steel shot blasting machines manufactured for China Construction Steel Structure Tianjin Company
8 sets of through-type shot blasting machines manufactured for Shanghai Baoye Steel Structure
So far, the performance of more than 600 set-type steel pass-through shot blasting machines at home and abroad is far ahead.
......
A large listed domestic agricultural equipment group phased out its outdated shot blasting machines in the past two years and fully adopted hook-type shot blasting machines independently developed and manufactured by Qingdao KEEJOO Group. Up to now, the group has purchased a total of 58 units.........
The various shot blasting machines manufactured by Qingdao KEEJOO Group for European clients are highly acclaimed and well-received.!
Introduction to the Components of the Shot Blasting Machine
1Blast wheel
1. The blast wheel and motor adopt Germany-joint developed high-efficiency HP technology. Compared with conventional old-style blast wheels, this design eliminates multiple friction loss links, lifting motor efficiency by 20%, cutting down fault points and slashing maintenance costs by 50%.
2. features a more compact footprint than traditional blast wheels, supports arbitrary installation angle arrangement, and enables far easier inspection and maintenance.
3. Constant blasting performance is maintained throughout operation, free from inconsistent and fluctuating cleaning quality seen on conventional units.
4. Blades and all wear-resistant consumables are manufactured in Taiwan via high-chromium investment precision casting, delivering outstanding abrasion resistance. Their service life ranges from 1,200 to 4,000 hours, 3–4 times longer than ordinary casting materials.
5. Blast wheel impeller: Treated with carburizing wear-resistant alloy. The impeller hub is one-time finished by high-precision CNC machining centers for ultra-high dimensional accuracy, ensuring perfect dynamic balance during high-speed rotation, low vibration, low noise and extended service life.
6. Equipped with SKF bearings imported from Sweden.
7. Fitted with genuine Siemens motors.
8. German Schenck dynamic balancing tester is applied to guarantee precise high-speed dynamic balance of impeller hubs.
2Flow control valve
1. Semi-automatic flow control system for regulating the flow of abrasive media into the blast wheel, featuring manual adjustment of the steel shot flow rate.
2. Fully sealed structural design, featuring a lockable inspection opening and equipped with two bearings.
3. A manual shut-off valve is installed above each flow valve; this can be closed to stop the flow of media from the hopper, thereby facilitating maintenance of the flow valve.
3Blasting chamber
1. The shot blasting chamber is constructed from welded manganese steel.
2. Manganese steel protective plates are installed in the "hot zone" of the chamber—specifically covering three-quarters of the area directly exposed to the blast stream—to prevent steel shot from striking the chamber's outer walls; these plates are suspended for easy installation, removal, and replacement.
3. A three-layer sealing structure is installed at the top to prevent steel shot from leaking out during the blasting process.
4Variable-frequency automatic speed-regulating conveyor system (comprising an infeed roller conveyor, a shot-blasting zone roller conveyor, and an outfeed roller conveyor with automatic speed regulation)
Roller conveyor pass-through type:1. The workpiece conveying system for the entire production line utilizes stepless variable-frequency speed control and consists of an input roller conveyor, a shot-blasting chamber roller conveyor, and an output roller conveyor.
2. The rollers for both the input and output roller tables are manufactured by welding heat-treated shaft ends to high-quality carbon steel seamless pipes, followed by integral machining on a lathe. Machining is performed after welding to ensure both a load-bearing capacity of 0.5 t/m and precise coaxiality.
3. The rollers within the shot blasting chamber that are subjected to the impact of the shot are all fitted with easily replaceable, wear-resistant sleeves made of special high-chromium-molybdenum iron.
4. The roller pitch is 600–800 mm, and the entire line utilizes variable-frequency speed control, enabling both high-speed and low-speed workpiece transport.
Wire mesh-belt conveyor type:
1. The system comprises dozens of transmission components, including carbon steel rollers, sprockets and chains, mesh belts, and bearings. The roller conveyor is divided into three sections: the infeed section, the shot-blasting section, and the discharge section. The rollers are constructed by precision-welding quenched-and-tempered end caps to high-quality seamless carbon steel pipes; their profiles and mounting dimensions are machined after welding to ensure compliance with load-bearing and coaxiality requirements.
2. The roller conveyors inside the blast chamber are equipped with easily replaceable wear-resistant medium-chromium cast iron sleeves. Labyrinth seals made of wear-resistant manganese steel are used at both ends of the roller shafts, completely preventing abrasive media from wearing down the bearings.
3. Utilizes imported HD wear-resistant manganese steel that has undergone solution and tempering treatments to eliminate internal residual stresses, moderately reduce the hardness of the manganese steel wire, and enhance its toughness and ductility.
4. A geared drive motor is installed on the right side of the conveyor belt and directly coupled to the drive roller, propelling both the belt and the workpieces; variable frequency speed control is employed, providing a conveying speed of 0.5–4 m/min.
5. A roller is installed under the driving shaft to serve as a guide and tensioner. When the steel mesh belt is loose, it can be tightened through this mechanism.
5Light curtain sensing system, automatic loading system/automatic unloading system
1. Two sets of light curtain sensing units are installed at the infeed and outfeed openings, respectively; the light curtain resolution can be selected based on workpiece size, and the units are used in pairs.
2. When a workpiece enters the shot blasting chamber, a light curtain at the inlet detects its presence, triggering a delayed start of the blast wheels. A light curtain sensor is also installed at the outlet; when the inlet and outlet sensors detect that no workpieces are passing through, the flow valve closes automatically and immediately to prevent "air blasting" (blasting without a workpiece present).
6Sorting system
1. A mesh screen separator is connected to the elevator and positioned above the magnetic separator; fine material passes through the screen into the magnetic separator, while coarse material and impurities are conveyed by a spiral mechanism along the screen to the discharge port at the rear.
2. It is designed to finely separate usable shot, broken shot, and dust, ensuring the uniformity of the shot media.
3.Featuring a welded structure, the interior contains multiple carefully designed compartments for airflow guidance. An access door on the front allows for routine inspection and maintenance; this door is equipped with an air inlet to provide the necessary airflow for dust separation.
4. An adjustable multi-vane baffle structure is used to regulate the uniformity of the falling abrasive curtain.
5. Stationary magnets installed at both the top and bottom enable the fine separation of usable shot from broken steel shot, ensuring the consistency of the blast media.
6. A storage hopper is connected at the bottom; after separation, the usable shot flows into the hopper for storage and subsequent reuse.
7Electrical control cabinet
1. Siemens PLC and touch screen
2. Siemens variable frequency drive (VFD) for speed control
3. Schneider low-voltage electrical components
4. Shot blasting time controller
5. AirTAC pneumatic components
6. Ammeter for flow monitoring
7. 1 lighting fixture
8. Dedicated constant-temperature air conditioning unit (optional)
8Dust collector
Pulse-jet cleaning system
Precision filter cartridge filtration system
High-efficiency three-stage dust removal
Optimized and upgraded Donaldson (USA) dust removal technology system
Standard configuration： |
| 1 | Electrical cabinet: This model comes standard with a cooling fan; air conditioning is available as an option. |
| 2 | Programmable Logic Controller (PLC): Siemens (other brands available as options upon customer request) |
| 3 | Touchscreen: Siemens (other brands available as options upon customer request) |
| 4 | Variable Frequency Drive (VFD): Inovance (China) — (Specific brands can be designated upon customer request; we recommend our domestic brand, as its quality is on par with or superior to Siemens.) |
| 5 | Power supply voltage: AC 380V, three-phase five-wire system |
| 6 | Low-voltage electrical components: Schneider (other brands available upon customer request) |
| 7 | Pneumatic components: ARITAC series (other brands available upon customer request) |
| 8 | Wires and cables |
| 9 | Qingdao KEEJOO Group can also customize various non-standard shot blasting machines according to your requirements.
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