Screw Rotor Suction-Side Area Reduces Gate Friction

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Solution Overview

Problem

In single screw compressors, the gate rotor's sliding contact with the screw rotor during the transition from suction to compression stroke leads to unnecessary power consumption due to sliding resistance, reducing efficiency.

Innovation Solution

The spiral grooves of the screw rotor are modified with suction-side areas on the side and bottom walls, reducing contact with the gate rotor until the compression chamber is completely closed, minimizing sliding resistance and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gate rotor is designed to slide along the spiral groove walls to seal the compression chamber, then the compression chamber can be completely closed, but sliding resistance increases power consumption

Engineering Contradiction:
Improvesealing of compression chamberVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention applies local quality by creating a suction-side area on the front side wall of the spiral groove where the gate rotor does not contact the screw rotor. This localized modification allows the gate to enter the spiral groove without sliding contact during the transition period, reducing friction and power consumption while maintaining sealing effectiveness when needed.

Inventive Principle:
Principle #3Local quality

2Reliability

If the gate rotor contacts the spiral groove walls continuously, then sealing is maintained, but wear and damage occur to the gate rotor

Engineering Contradiction:
Improvesealing of compression chamberVSAvoidwear and damage to gate rotor
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the harmful contact portion by removing the front side wall surface of the spiral groove to create the suction-side area. This extraction eliminates the source of unnecessary sliding contact and wear during the transition period from suction to compression stroke, while the remaining structure maintains sealing functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the gate rotor enters the spiral groove smoothly, then the compression chamber can be sealed, but sliding resistance causes energy loss

Engineering Contradiction:
Improvesmooth entry of gate rotorVSAvoidenergy loss due to sliding resistance
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The invention converts the potentially harmful sliding contact into a beneficial non-contact entry by creating the suction-side area. The gate rotor can enter the spiral groove smoothly without friction during the transition period, and the suction-side area design actually benefits from this non-contact entry by preventing energy loss while maintaining the ability to seal when required.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 power consumption by minimizing sliding resistance between the gate and screw rotor, enhancing the efficiency of the single screw compressor and preventing damage or wear to the gate rotor.

Implementation Method 1

the gate (211) slidably contacts a side wall surface (202) of the spiral groove (201)... slidably contacts a bottom wall surface (204) of the spiral groove (201), followed by slidably contacting a side wall surface (203) of the spiral groove (201)... power is consumed due to sliding resistance therebetween

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2182217B1Single-screw compressor, and screw rotor machining method
Publication Date: 2016.09.28 DAIKIN INDUSTRIES LTD
  • EP2182217B1 patent drawingFigure 1
  • EP2182217B1 patent drawingFigure 2
  • EP2182217B1 patent drawingFigure 3

AI summary

In a screw rotor (40), a first suction-side area (45) is formed in a first side wall surface (42) of a spiral groove (41). In the first side wall surface (42), a portion extending from a start point to a point until immediately before a compression chamber (23) is in a completely-closed state defines the first suction-side area (45). The first suction-side area (45) is thinner than a portion of the first side wall surface (42) other than the first suction-side area (45), and does not contact a gate (51) of a gate rotor (50).