Reciprocating Compressor Inverted Crank Mechanism
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Solution Overview
Problem
Positive-displacement reciprocating compressors face issues with frictional forces, dimensional and weight increases, balance difficulties, structural complexity, and reliability problems due to conventional crank mechanisms, as well as inefficient lubrication systems and valve systems that lead to increased production costs and overheating.
Innovation Solution
A non-conventional crank mechanism using a sintered material with self-lubricating properties and a targeted lubrication system that draws power from the drive shaft, combined with a single-plate valve system to reduce components and clearances, simplifying assembly and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional crank mechanism is used, then the compressor can operate with a standard structure, but frictional forces increase and the piston rod length must be increased to reduce seizure risk, causing dimensional and weight increase
Solution Approach 1:
The patent inverts the conventional crank mechanism by making the connecting rod the rotating element instead of the crank. The connecting rod rotates about a fixed point on the crankshaft, while the crank pin moves in a circular path. This inversion eliminates the need for a long piston rod, reducing weight and inertial forces while maintaining reliability by avoiding seizure through proper lubrication points.
Solution Approach 2:
The patent changes the kinematic parameters of the mechanism by altering the rotation point and motion path. Instead of the crank rotating about a fixed center, the connecting rod rotates about a fixed point on the crankshaft, changing the motion characteristics and reducing the required piston rod length while maintaining the necessary stroke and compression ratios.
2Reliability
If the piston rod length is increased to reduce seizure risk, then reliability improves, but dimensional size and weight increase with concomitant increase of inertial forces
Solution Approach 1:
By inverting the mechanism so the connecting rod rotates rather than the crank, the patent eliminates the need for excessive piston rod length. The rotation point is fixed on the crankshaft, allowing the connecting rod to serve dual functions as both the rotating element and the drive link, simplifying the overall mechanism dimensions while maintaining seizure resistance through proper lubrication.
3Device complexity
If a non-conventional crank mechanism is used, then frictional forces and structural complexity are reduced, but the mechanism requires precise lubrication to maintain reliability
Solution Approach 1:
The patent incorporates self-lubricating features directly into the mechanism. The connecting rod rotation point on the crankshaft is designed with embedded lubricant reservoirs or self-lubricating materials that automatically provide lubrication during operation. This self-service approach maintains reliability by ensuring continuous lubrication without requiring complex external lubrication systems.
4Productivity
If traditional valve systems are used, then the compressor can operate with standard valve arrangements, but the number of components increases and assembly becomes more difficult
Solution Approach 1:
The patent combines multiple valve functions into integrated valve assemblies. Instead of separate suction and delivery valves with individual mounting, the valves are merged into a unified system where the valve plate serves multiple functions and the valve components are pre-assembled as modules. This merging reduces the total number of parts while maintaining compression efficiency through proper valve timing and sealing.
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
The solution reduces friction, weight, and complexity, enhances reliability, and lowers production costs while providing precise lubrication and reducing overheating, resulting in a more efficient and cost-effective compressor design.
Implementation Method 1
a planet, realised in a material with self-lubricating properties
Data Source
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AI summary
A positive-displacement reciprocating compressor comprising a "non-conventional" crank mechanism which eliminates the amount of frictional force between the wall of the piston and the wall of the cylinder, whose characteristic feature is to have a planet (20) made of sintered material, with self-lubrication properties, allowing to eliminate bushings or similar additional elements. An economical and structurally simple lubrication system, which preferably comprises a classical link rod/crank mechanism, utilises the mechanical energy provided by the drive shaft of the compressor and sends the lubricant (oil) in a precise manner to the surfaces that need to be lubricated. This oil is easily retained by the very small grains of the sintered material. Moreover, a valve system based on a single plate simplifies the structure of the cylinder unit (30).