Fluid-Injected Screw Compressor Element with Direct Contact Bearings
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Solution Overview
Problem
Conventional screw-type compressor elements with oil or water injection face challenges such as high costs, complex assembly, and leakage losses due to the use of expensive radial and axial roller bearings, which increase production costs and vibro-acoustic noise.
Innovation Solution
A fluid-injected screw-type compressor element with rotors radially and axially bearing-mounted directly to the housing, utilizing a hard, almost frictionless coating and potentially one additional bearing to minimize friction, eliminating the need for additional radial bearings and simplifying the design, while using a low-viscosity fluid for lubrication and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If radial and axial roller bearings are used to reduce friction between rotors and housing, then friction is reduced and rotor operation is improved, but production costs increase and device complexity increases
Solution Approach 1:
The invention extracts and eliminates the radial and axial roller bearings from the compressor element design. Instead of using these complex bearing components, the patent employs a fluid injection system that directly reduces friction between the rotors and housing through injected fluid, thereby simplifying the overall structure and reducing production costs while maintaining effective rotor operation.
Solution Approach 2:
The invention applies pneumatic/hydraulic principles by injecting fluid (such as air or lubricating oil) directly into the contact zones between the rotors and housing. This fluid injection creates a lubricating film that reduces friction and wear, replacing the need for mechanical roller bearings with a fluid-based friction reduction mechanism.
2Reliability
If radial and axial roller bearings are used to absorb radial forces and limit vibration transmission, then rotor stability is improved and vibration transmission is reduced, but device complexity and production cost increase
Solution Approach 1:
The invention removes the complex radial and axial roller bearing structures from the design. Instead, it uses a simplified fluid injection system that delivers lubricating fluid directly to the rotor-housing contact points, providing necessary lubrication and vibration damping without the complexity of multiple bearing components.
Solution Approach 2:
The fluid injection system enables the compressor element to self-lubricate and self-damp vibrations. The injected fluid automatically forms lubricating films at contact zones and provides vibration damping, allowing the system to maintain rotor stability and reduce vibration transmission without requiring complex external bearing structures.
3Reliability
If water-lubricated slide bearings with corrosion-free bush are used, then rotor lubrication and sealing are improved, but manufacturing cost increases due to expensive materials and high manufacturing tolerance requirements
Solution Approach 1:
The invention extracts and eliminates the water-lubricated slide bearings with corrosion-free bush from the design. Instead of using these expensive bearing components with high manufacturing tolerance requirements, the patent employs direct fluid injection into the compression chamber and contact zones, providing necessary lubrication and sealing functions without the associated manufacturing costs.
Solution Approach 2:
The invention uses fluid injection (pneumatic or hydraulic) to deliver lubricating fluid directly to the rotor-housing contact zones and compression chamber. This fluid-based approach provides effective lubrication and sealing while avoiding the need for expensive corrosion-free bush materials and high-precision bearing manufacturing.
4Reliability
If conventional bearing designs are used, then rotor support is provided, but leakage losses occur between rotors and between rotors and housing wall
Solution Approach 1:
The invention uses fluid injection to create pressurized lubricating films in the gaps between rotors and between rotors and housing wall. The injected fluid (such as air or lubricating oil) increases the pressure in these clearance zones, counteracting the pressure differential that drives leakage, thereby reducing energy losses while maintaining proper rotor support.
Solution Approach 2:
The invention changes the pressure parameter in the clearance zones by injecting fluid at controlled rates. This increases the local pressure in the gaps between rotors and between rotors and housing, reducing the pressure gradient that causes leakage and thereby minimizing energy losses while maintaining rotor positioning.
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 reduces production and material costs, minimizes leakage losses, and enhances efficiency by reducing friction and vibro-acoustic emissions, resulting in a more compact, cost-effective, and longer-lasting compressor element.
Implementation Method 1
a hard, almost friction less coating which is provided over at least an end face of at least one of the rotors (2 and 3)
Implementation Method 2
utilizing a hard, almost frictionless coating and potentially one additional bearing to minimize friction, eliminating the need for additional radial bearings and simplifying the design, while using a low-viscosity fluid for lubrication and sealing
Implementation Method 3
using a low-viscosity fluid for lubrication and sealing
Data Source
Figure 1
AI summary
Fluid-injected screw-type compressor element comprising two co-operating rotors (2 and 3) which are radially and axially bearing-mounted in a housing (1), whereby this housing confines a rotor chamber (4) in which the rotors (2 and 3) are situated and in which a fluid circuit (11) for the injection of a fluid discharges, characterised in that the radial bearing of at least one rotor is formed by the contact of the rotor concerned with the part of the wall of the housing opposite the radial perimeter of the rotor concerned and/or the co-operation with the other rotor and by maximally one additional radial bearing.