Variable Pitch Helical Shaft for Sludge Dewatering
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Solution Overview
Problem
Conventional multi plate screw press sludge dewatering machines have limitations including a narrow treatment range, shaft jamming and sticking issues, high breakage rate of plastic laminations, poor abrasion and corrosion resistance, complex and labor-intensive assembly, and reduced maintenance efficiency.
Innovation Solution
The design incorporates a helical shaft with a variable diameter and pitch, ultra-abrasion-resistant hard alloy layers, carbon fiber reinforced plastics (CFRP) composite material for rings, and a hydraulic or variable frequency motor drive, along with integrated regulation blocks for simplified assembly and enhanced structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multi plate screw press sludge dewatering machine is used, then the equipment can perform basic dewatering function, but the treatment range is narrow and cannot effectively handle sludge with water content higher than 98%
Solution Approach 1:
The dewatering machine is divided into multiple independent dewatering chambers (first, second, third dewatering chambers) with different structural parameters. Each chamber has specific filtering gap sizes and helical shaft pitch configurations optimized for different sludge characteristics, enabling the system to handle a broader range of sludge types and water contents through selective chamber operation.
2Productivity
If the lift angle of helical blade is set to 8-13° with gradual reduction from inlet to outlet, then the dewatering capacity is improved, but sludge sticking and shaft jamming occur when discharged sludge has low water content
Solution Approach 1:
Different sections of the helical shaft are equipped with helical blades having different lift angles tailored to local dewatering requirements. The first helical shaft section has a larger lift angle (10-15°) suitable for high water content sludge, while the second section has a smaller lift angle (5-10°) for low water content sludge, preventing sticking and jamming in different operational zones.
3Ease of manufacture
If plastic lamination is adopted for concentration section of helical shaft, then the manufacturing cost is reduced, but the lamination is easy to break and inadequate in strength
Solution Approach 1:
The helical shaft adopts a composite structure combining plastic lamination with metal reinforcement. The plastic lamination provides corrosion resistance and cost-effectiveness, while embedded metal elements (such as steel wires or metal layers) provide the necessary mechanical strength and breakage resistance, creating a material composite that balances both manufacturing economy and structural integrity.
4Strength
If metal material such as 304 stainless steel is used for lamination, then the structural strength is improved, but the abrasion resistance and corrosion resistance are poor with service life of only about 1 year
Solution Approach 1:
The lamination structure uses plastic material (such as polyurethane or polyethylene) as the base layer providing inherent corrosion resistance, combined with耐磨 (wear-resistant) material layers (such as rubber compounds or ceramic coatings) on the surface. This composite material configuration simultaneously achieves high structural strength, excellent corrosion resistance, and superior abrasion resistance, extending service life significantly beyond conventional metal materials.
5Adaptability or versatility
If conventional assembly method with separate regulation blocks is used, then the adjustment flexibility is maintained, but the assembly process is labor-intensive and prone to mistakes
Solution Approach 1:
The regulation blocks are integrated with the fixed rings to form an integrated assembly unit. The regulation blocks are pre-positioned and fixed on the fixed rings during manufacturing, creating a combined component that maintains adjustment flexibility while eliminating separate assembly steps. This integration reduces the number of discrete parts, simplifies the assembly process, and minimizes assembly errors while preserving the ability to adjust filtering gaps.
6Speed
If helical bevel gear speed reducer or worm-gear speed reducer is used, then the speed reduction ratio is achieved, but the device is heavy and inconvenient to maintain with low safety coefficient
Solution Approach 1:
The conventional mechanical speed reduction system (helical bevel gear or worm-gear) is replaced with a hydraulic drive system. The hydraulic motor directly drives the helical shaft, eliminating complex gear mechanisms. This substitution provides high torque at low speed without heavy gears, improves safety through inherent overload protection in hydraulic systems, and reduces maintenance requirements by eliminating gear lubrication and alignment issues.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design broadens the treatment range, reduces shaft jamming, increases service life of components, improves maintenance efficiency, and enhances the overall performance and durability of the dewatering machine.
Implementation Method 1
the helical shaft rotates to drive the sludge from the concentration portion to the dewatering portion
Implementation Method 2
the sludge pressurizes the movable rings to drive the movable rings to move between the fixed rings during rotation, and most of water flows to a filtrate recycling device through the gaps
Data Source
AI summary
The present invention provides a multi plate screw press sludge dewatering machine and a helical shaft thereof. The multi plate screw press sludge dewatering machine includes fixed rings, movable rings, the helical shaft, a sludge inlet tank and a sludge discharging tank; the helical shaft adopts a variable diameter variable pitch helical shaft, a lead angle arrangement sequence of a helical blade of the whole helical shaft is gradual reduction from the sludge discharging tank to the sludge inlet tank, and the lead angle arrangement sequence is gradually reduced from 16°-22° to 6°-14°; a pitch of the helical shaft is gradually increased along a direction from the sludge inlet tank to the sludge discharging tank; a diameter of a shaft body of the helical shaft is gradually increased along with a direction of the sludge discharging tank from a ⅓ position of a shaft length; and blockage prevention plates are arranged on two sides of the bottom of the helical blade. The helical shaft in the present invention is specially designed, so that the pitch is more reasonable, a helical angle is gentler, frictional resistance when sludge passes through the helical shaft may be effectively reduced, and phenomena of shaft blockage and shaft sticking of the sludge may be reduced.