Low-Density Blade Rotary Compressor for Two-Stage Systems
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Solution Overview
Problem
In two-stage compression systems, the use of an intermediate-pressure-housing type rotary compressor as the low-stage-side compressor leads to blade jumping due to lower back pressure, causing gas leakage and efficiency issues, despite efforts to reduce inertial force in single-stage rotary compressors.
Innovation Solution
The implementation of a rotary compressor with blades made of materials having a density of 3 g/cm³ or less to reduce inertial force, combined with a high-stage-side scroll compressor, ensures efficient operation across a wide range without blade jumping, using HFC, HFO, or HC refrigerants, and materials like carbon or aluminum alloy blades for enhanced heat and abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blade is made lighter to reduce inertial force, then blade jumping is prevented in single-stage rotary compressors, but gas leakage occurs inside the cylinder due to blade jumping in intermediate-pressure-housing type two-stage compressors
Solution Approach 1:
The patent changes the material density parameter of the blade from conventional materials (steel, aluminum alloy) to a low-density material with density of 3 g/cm³ or less. This parameter change reduces the inertial force of the blade during rotation, preventing blade jumping even in the intermediate-pressure-housing type two-stage compressor where the back pressure is lower. The reduced inertial force ensures the blade maintains proper contact with the rotor surface, preventing gas leakage while maintaining compression efficiency.
2Productivity
If the compressor rotating speed is increased by inverter control, then compression efficiency is improved, but blade jumping occurs due to increased inertial force
Solution Approach 1:
The patent applies parameter change by selecting a blade material with density of 3 g/cm³ or less, which fundamentally alters the mass parameter of the blade. This allows the compressor to operate at higher rotating speeds enabled by inverter control without experiencing blade jumping. The reduced density directly reduces inertial force (F = m × a), allowing the blade to follow the rotor rotation smoothly even at high speeds, thus maintaining both compression efficiency and operational reliability.
3Loss of energy
If the back pressure is reduced in intermediate-pressure-housing type compressor, then compression differential is reduced and leakage loss is reduced, but blade jumping occurs due to lower back pressure
Solution Approach 1:
The patent resolves this contradiction by changing the material density parameter of the blade to 3 g/cm³ or less. This parameter change reduces the blade's inertial force, allowing it to maintain proper contact with the rotor surface even when the back pressure is reduced. The lower back pressure in intermediate-pressure-housing type compressors creates smaller compression differentials that reduce leakage loss, while the low-density blade prevents blade jumping that would otherwise occur under these reduced pressure conditions.
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 configuration significantly reduces blade jumping and gas leakage, enhancing compression efficiency and securing a wide operational range with reduced leakage loss in the two-stage compressor system.
Implementation Method 1
a low-stage-side compressor for compression from a low pressure to an intermediate pressure
Implementation Method 2
a high-stage-side compressor for compression from the intermediate pressure to a high pressure
Data Source
Figure 1
Figure 2
Figure 3(A)~3(C)
AI summary
A two-stage compressor (1) is an intermediate-pressure-housing type two-stage compressor which includes a low-stage-side compressor (2) and a high-stage-side compressor (3) both provided inside a housing (10), and in which a refrigerant compressed to an intermediate pressure in the low-stage-side compressor (2) is discharged inside the housing (10) and the intermediate-pressure refrigerant is sucked into the high-stage-side compressor (3) and compressed to a high pressure. The low-stage-side compressor (2) is a rotary compressor equipped with a blade (26) partitioning an inside of a cylinder chamber into a suction side and a compression side and the blade reciprocates in response to rotation of a rotor (24). The blade (26) is formed of a material having a density of 3 g/cm 3 or less so as to reduce the blade's inertial force in response to a lower back pressure acting on a back surface of the blade.