Screw compressor and refrigeration device

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Solution Overview

Problem

The interference between the spindle and rotary table of a 5-axis machining center occurs when machining helical grooves in screw rotors due to large relative angles, particularly at the axial ends, necessitating additional operations to avoid interference.

Innovation Solution

Refine the shape of the gates to ensure the maximum angle between the center axis of the screw rotor and the side wall surfaces of the helical grooves is 145 degrees or less, forming the corner portions between the bottom and side wall surfaces in a curved shape, and using a taper end mill for machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a screw compressor is used in a refrigeration device, then the refrigeration capacity can be improved, but the risk of liquid slugging and mechanical damage increases when the suction pressure is lower than the evaporator pressure

Engineering Contradiction:
Improverefrigeration capacityVSAvoidrisk of liquid slugging and mechanical damage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A pressure equalization valve is introduced as an intermediary device between the evaporator and the screw compressor. This valve controls the opening and closing of the communication passage to equalize pressures, preventing liquid slugging and mechanical damage while maintaining refrigeration capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pressure equalization valve dynamically adjusts the communication between the evaporator and compressor based on pressure differential. When suction pressure is lower than evaporator pressure, the valve opens to equalize pressures; when suction pressure is higher, the valve closes, enabling adaptive pressure control

Inventive Principle:
Principle #15Dynamics

2Reliability

If a pressure equalization valve is added to prevent liquid slugging, then the reliability improves, but the device complexity increases

Engineering Contradiction:
Improveprotection against liquid sluggingVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure equalization valve serves multiple functions: it equalizes pressures to prevent liquid slugging, controls refrigerant flow, and protects the compressor. This multi-functionality reduces the need for additional separate components, minimizing the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The pressure equalization function is merged with the existing refrigeration system components. The valve integrates the pressure control function into the refrigerant flow path, combining pressure equalization and flow control in a single component rather than adding separate systems

Inventive Principle:
Principle #5Merging (Combining)

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 approach avoids interference between the spindle and rotary table during machining, allowing seamless operation of the 5-axis machining center and enabling the formation of helical grooves between seal end portions, facilitating the production of screw compressors.

Implementation Method 1

a pressure equalization valve equalizing a suction pressure and an evaporator pressure by controlling opening and closing of a communication passage between the evaporator and the compressor

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP4477886B1Screw compressor and refrigeration device
Publication Date: 2026.04.29 DAIKIN INDUSTRIES LTD
  • EP4477886B1 patent drawingFigure 1
  • EP4477886B1 patent drawingFigure 2
  • EP4477886B1 patent drawingFigure 3

AI summary

Gates (52) each have a first seal line (55) and a second seal line (56). A shape of the first seal line (55) and a shape of the second seal line (56) are asymmetric with respect to a first imaginary straight line (L1) passing through a rotation center (O) of a gate rotor (51) and a first intermediate position (A) located on a tip end side of each of the gates (52) between the first seal line (55) and the second seal line (56). Helical grooves (40) each have a shape corresponding to each of the gates (52).