Pipeless Screw Compressor Suction Bypass for Vibration Damage

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Solution Overview

Problem

The existing systems with external pipes in screw compressors face issues such as increased cost and complexity due to numerous parts, vulnerability to vibrations, and potential for dust and dirt accumulation, which complicates maintenance and increases the risk of damage during compressor movement.

Innovation Solution

A pipeless structure is implemented by providing an intake-gas bypass flow path and oil recovery system with check valves integrated into the compressor housing, eliminating the need for external pipes and reducing the number of parts, while ensuring reliable reverse-flow inhibition through strategically placed blocking sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external pipes are used to communicate with the suction chamber and provide reverse-flow inhibition mechanisms, then liquid reverse-flow prevention is achieved, but the number of parts increases, cost increases, and the risk of pipe damage due to vibrations increases

Engineering Contradiction:
Improveliquid reverse-flow preventionVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the reverse-flow inhibition mechanism directly into the suction chamber structure, merging the function of external pipes with the chamber itself. The blocking sections are formed as integral parts of the suction chamber wall, eliminating the need for separate external pipes and joints, thereby reducing the number of parts while maintaining liquid reverse-flow prevention capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces blocking sections as intermediary structures within the suction chamber that serve as internal barriers to prevent liquid reverse-flow. These blocking sections act as mediators between the suction chamber and the compressor body, providing the same function as external pipes with check valves but with fewer parts and reduced complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If external pipes are used to communicate with the suction chamber, then system functionality is achieved, but spatial occupation increases and handling convenience decreases

Engineering Contradiction:
Improvesystem functionalityVSAvoidspatial occupation
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent combines the functions of external pipes and reverse-flow inhibition mechanisms into the internal structure of the suction chamber. The blocking sections are formed as integral parts of the chamber wall, eliminating the need for separate external piping systems, thereby reducing spatial occupation while maintaining full system functionality

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If external pipes with check valves are used, then reverse-flow inhibition is provided, but maintenance complexity increases due to dust and dirt accumulation

Engineering Contradiction:
Improvereverse-flow inhibitionVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent extracts the reverse-flow inhibition function from external pipes and relocates it to the internal structure of the suction chamber. The blocking sections are formed as integral parts of the chamber wall, eliminating the need for external pipes that would accumulate dust and dirt, thereby reducing maintenance complexity while maintaining reverse-flow inhibition capability

Inventive Principle:
Principle #2Taking out (Extraction)

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 reduces the risk of pipe damage, minimizes spatial occupation, lowers costs, and enhances handling convenience by eliminating the need for external pipes and reducing the risk of reverse-flow inhibition failures, ensuring reliable operation and maintenance.

Implementation Method 1

a first check valve arranged in said intake-gas bypass flow path

Methodology Applied
Scientific EffectCheck valve reverse-flow inhibition: Valve

Implementation Method 2

a first blocking section provided between said secondary-side opening section and the meshing sections, and covering said secondary-side opening section in a separated state

Methodology Applied
Scientific EffectPhysical blocking: Physical Containment

Implementation Method 3

The suction throttle is opened and closed for adjustment of intake-gas amount or load of the compressor

Methodology Applied
Scientific EffectThrottle valve flow control: Valve

Implementation Method 4

a liquid is fed into working chambers for lubrication, cooling, sealing or the like

Methodology Applied
Scientific EffectLiquid cooling: Cooling

Implementation Method 5

a liquid is fed into working chambers for lubrication, cooling, sealing or the like

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3722610B1Liquid-feeding screw compressor
Publication Date: 2024.10.09 HITACHI IND EQUIP SYST CO LTD
  • EP3722610B1 patent drawingFigure 1
  • EP3722610B1 patent drawingFigure 2
  • EP3722610B1 patent drawingFigure 3

AI summary

A liquid-injected screw compressor includes: a casing that houses a screw rotor and a bearing, and has a suction port and a suction chamber connected to the suction port; a suction throttle valve that is installed at the suction port, and has a housing; and an intake-gas bypass system that establishes communication between a primary side and a secondary side of the suction throttle valve. The intake-gas bypass system includes: an intake-gas bypass flow path that is provided in a wall section of the housing, and has a primary-side opening section opening into the primary side of the suction throttle valve, and a secondary-side opening section opening into the secondary side of the suction throttle valve; and a first check valve arranged in the intake-gas bypass flow path. The intake-gas bypass flow path has an external opening section that opens to an outside of the housing and that allows insertion and withdrawal of the first check valve. Thereby, it is possible to make the system that communicates with the suction chamber in the casing and is provided with the reverse-flow inhibition mechanism a pipeless structure without impairing advantages of external pipes.