Scroll Compressor Back Pressure Chamber Discharge Guide
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Solution Overview
Problem
The upper back pressure type scroll compressor faces challenges in quickly re-operating due to residual pressure in the back pressure chamber, leading to increased initial torque and noise, as the refrigerant from the back pressure chamber is not efficiently discharged to the compression and suction sides when the compressor stops, causing the fixed scroll to remain closely attached to the orbiting scroll.
Innovation Solution
A scroll compressor design with a discharge guide in the orbiting scroll and a volume ratio of the discharge space to the back pressure chamber set at 20:1 or more, allowing the floating plate to quickly move downward and discharge the refrigerant, and a recessed discharge guide to ensure continuous communication between the back pressure chamber and compression chamber, facilitating the discharge of intermediate pressure refrigerant when the compressor stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the back pressure chamber is formed on the bottom surface of the orbiting scroll (lower back pressure type), then the structure is simple and bypass hole formation is easy, but the back pressure chamber changes configuration and position according to orbiting motion, causing the orbiting scroll to tilt and increasing vibration and noise
Solution Approach 1:
The patent inverts the conventional lower back pressure type design by placing the back pressure chamber on the top surface of the fixed scroll instead of the bottom surface of the orbiting scroll. This inversion makes the back pressure chamber stationary and fixed in configuration, preventing orbiting scroll tilt and reducing vibration and noise, while still maintaining structural simplicity.
2Reliability
If the end of the wrap and head plate are strongly attached to prevent refrigerant leakage, then sealing is improved, but friction resistance increases causing more noise and abrasion
Solution Approach 1:
The patent introduces a back pressure chamber that applies controlled pressure to the wrap-end interface, dynamically adjusting the attachment force between the wrap end and head plate. This parameter change allows the system to maintain adequate sealing while reducing excessive friction, noise, and abrasion that would occur with constant strong attachment.
3Use of energy by moving object
If the compressor stops operation, then energy consumption is reduced, but residual pressure in the back pressure chamber maintains fixed scroll attachment to orbiting scroll, increasing initial torque for restart
Solution Approach 1:
The patent extracts and separately manages the pressure control function by introducing a discharge guide that selectively connects the back pressure chamber to either the compression chamber or suction chamber. This allows residual pressure to be discharged to reduce initial torque requirements for restart, while maintaining energy efficiency during stopped operation.
4Productivity
If the discharge space volume is increased relative to back pressure chamber volume, then refrigerant discharge efficiency is improved, but the overall compressor size increases
Solution Approach 1:
The patent employs dynamic volume control through a discharge guide that can be positioned in different states. During normal operation, the discharge guide connects the back pressure chamber to the compression chamber maintaining compact size. During restart conditions, it connects to the suction chamber to enable efficient refrigerant discharge, providing dynamic adaptability without permanent size increase.
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 enables the scroll compressor to quickly re-operate by maintaining equilibrium pressure and efficiently discharging the back pressure chamber's refrigerant, reducing the initial torque and noise, and improving operational efficiency.
Implementation Method 1
the refrigerant from the back pressure chamber is not efficiently discharged to the compression and suction sides when the compressor stops
Implementation Method 2
The orbiting scroll revolves with respect to the fixed scroll, thereby reducing a volume of a compression chamber, which is formed between the fixed scroll and the orbiting scroll according to an orbiting motion of the orbiting scroll, thus increasing a pressure of a fluid
Data Source
AI summary
A scroll compressor is provided that may include a casing including a rotational shaft, a cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space, a first scroll that is revolved by rotational of the rotational shaft, a second scroll disposed on or at a side of the first scroll to define a plurality of compression chambers together with the first scroll, the second scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers, a back pressure plate coupled to the second scroll, the back pressure plate having an intermediate pressure suction hole that communicates with the intermediate pressure discharge hole, and a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate. The discharge space may have a volume greater by a set ratio or more than a volume of the back pressure chamber.