Research on Optimization Design and Performance Enhancement of Vacuum Extruders
Based on Engineering Practice of Structural Improvement of Dual-Stage Vacuum Extruders
In a fired brick production line, the clay fired brick vacuum extruder is the core shaping equipment that determines the quality of green bricks and production efficiency. With the brick and tile industry's increasing demands for product quality, output, and equipment reliability, structural optimization and technological upgrading of vacuum extruders have become particularly important.
By researching and analyzing various vacuum extruder equipment developed domestically and internationally, and combining the advanced technical experience of different manufacturing enterprises, a systematic optimization design of key structures is carried out while ensuring equipment performance. By selecting technologically mature and economically reasonable supporting components, equipment functionality is enhanced while effectively reducing manufacturing costs, thereby achieving a comprehensive improvement in both equipment performance and economy.
I. Optimization Design of Key Components
1.1 Auger Shaft (Main Shaft) Structure Optimization
The auger shaft is the core transmission component of the vacuum extruder. Its main function is to transmit power and push the clay mixture forward, while simultaneously bearing significant torque and axial pressure. Therefore, the structural design of the auger shaft directly affects the overall stability and reliability of the machine.
In the original vacuum extruder structure, the diameter of the auger shaft at the bearing positions was Φ170 mm, and it utilized three bearings for support (including one thrust bearing). However, during actual operation, this structure presented the following problems:
• Relatively small center distance between the front and rear bearings
• Relatively long cantilevered section of the auger shaft
• Significant deflection of the shaft during operation
This structure tended to cause noticeable shaking of the extruder head during operation (commonly known as the "head shaking" phenomenon). Excessive or prolonged shaking not only affects the operational stability of the equipment but can also lead to component damage and even production shutdowns.
According to mechanical theory analysis:
Assume the distance from the front bearing center of the auger shaft to the front end of the auger is L₁
Assume the center distance between the front and rear bearings is L₂
When the following condition is met:
L₂ / L₁ ≥ 0.7
the auger shaft can maintain good operational stability.
In the original equipment structure:
L₂ / L₁ = 1040 / 1950 = 0.533
This is significantly below the reasonable design range, thus indicating a structural design deficiency.
1.2 Structural Improvement Scheme
During the optimization design process, the key transmission structure was adjusted to achieve a more rational auger shaft configuration.
Main measures included:
• Changing the original radial pneumatic clutch to an axial pneumatic clutch
• Reducing the axial installation dimensions of the clutch
• Moving the auger shaft bearing housing rearward
Through the above optimizations:
The center distance between the front and rear bearings increased by approximately 400 mm.
Under the new structure:
L₂ / L₁ = (1040 + 400) / 1950 = 0.74
This ratio now meets the requirements for stable operation, making the auger shaft run more smoothly and reliably.
Due to the increased structural rigidity, the auger shaft diameter could also be optimized accordingly:
Original maximum shaft diameter: Φ185 mm
Optimized bearing section diameter: Φ150 mm
Maximum shaft diameter: Φ160 mm
After structural optimization:
• The shaft weight is significantly reduced
• The mechanical structure is more rational
• Manufacturing difficulty is decreased
Simultaneously, the dimensions of bearings and related components were also reduced, making the entire auger shaft system more compact.
II. Pneumatic Clutch System Optimization
In the original equipment design, a radial pneumatic clutch was used as the power connection device. This structure had the following disadvantages:
• Complex structure
• Large footprint
• High requirements for installation and commissioning
• Strict requirements for equipment alignment accuracy
The radial pneumatic clutch required precise alignment with the reducer via a coupling and needed additional support structures, making installation and maintenance more complex.
In the optimization design, all radial clutches were replaced with axial pneumatic clutches, installed directly on the high-speed shaft of the reducer.
This structure offers the following advantages:
• More compact structure
• Easier to ensure installation accuracy
• More convenient commissioning and maintenance
• Significantly reduced equipment weight
• Lower requirements for the compressed air system
Through this improvement, not only was the operational reliability of the equipment enhanced, but the overall transmission structure also became simpler.
III. Enhancement of Equipment Production Capacity
The original dual-stage vacuum extruder suffered from relatively low output in practical use. Technical analysis identified the main reasons as:
• Insufficient feeding capacity from the upper stage
• Excessive compression ratio in the tapered cavity
• Relatively low conveying speed in the upper stage
Compression ratio of the original equipment's tapered cavity:
λ = 2.6
This value was close to the upper limit of the design allowable range.
The typical reasonable range is:
λ = 2.0 – 2.6
An excessively large taper reduces the conveying speed of the clay mixture, decreasing the amount of material entering the vacuum chamber per unit time, thus limiting the overall machine output.
In the optimization design, by adjusting the structural dimensions of the inner and outer tapered sleeves, the compression ratio was optimized to:
λ = 2.3
Furthermore, due to the replacement with the axial clutch, the rotational speed of the upper stage was appropriately increased, significantly enhancing the clay conveying capacity.
After optimization:
The amount of clay mixture entering the vacuum chamber per unit time increased by approximately 22%.
The production capacity of the new dual-stage vacuum extruder improved by about 25% compared to the original model.
IV. Structural Lightweighting and Manufacturing Optimization
During the overall equipment optimization process, systematic improvements were made to several structural components to enhance manufacturing efficiency and structural rationality.
4.1 Structural Weight Optimization
While ensuring equipment strength and performance, structural optimization was carried out on the following key components:
• Feeding box
• Vacuum chamber
• Machine body structure
By optimizing casting structures and machining processes, the overall weight of the equipment was significantly reduced, while processing efficiency was improved.
4.2 Standardization of Component Design
In the original equipment design, some auxiliary components such as:
• Filters
• Motor slide rails
• Lighting systems
• Vacuum chamber inspection doors
• Varied in structure across different equipment models.
In the optimization design, by implementing standardized component design, the following goals were achieved:
• Utilizing unified structural parts for different equipment models
• Making only appropriate dimensional adjustments
• Establishing a system of internal enterprise standard parts
This measure brought significant production advantages:
• Reduction in the variety of parts
• Increased batch production capability
• Enhanced processing efficiency
• Reduced manufacturing complexity
V. Effects of Optimization Design
Structure
• More compact equipment structure
• More rational transmission system
• Increased standardization of components
Performance
• More stable operation of the auger shaft
• Significantly improved production capacity
• Enhanced equipment operational reliability
Manufacturing
• Optimized equipment weight
• Improved processing and manufacturing efficiency
• More rational overall structure
In summary, the optimization design has not only elevated the equipment's technical level but also improved production efficiency and equipment reliability, enabling the vacuum extruder to deliver greater value in brick production lines.
