Compressor Unloader Lid Structure for Easier Seal Maintenance

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Solution Overview

Problem

Existing unloader designs for compressors require complex and error-prone servicing processes, involving the removal of the entire unit to replace seals and slide rings, which is physically demanding and exposes the compressor to dirt, leading to potential damage and inadequate sealing.

Innovation Solution

The unloader design incorporates a housing with a moveable piston rod and a lid that houses the piston, allowing the lid to be removed for easy access to the sealing means without dismounting the entire unit, reducing the weight and number of steps required for maintenance, and maintaining the compressor inlet's seal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the entire unloader is demounted to replace seals and slide rings, then the sealing components can be accessed and replaced, but the servicing process becomes complex, time-consuming, and physically demanding

Engineering Contradiction:
Improveaccessibility of sealing componentsVSAvoidnumber of disassembly actions
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The unloader is divided into separable components: the housing and the lid. The lid can be removed independently from the housing to access the piston, seal, and slide ring, while the housing remains mounted on the compressor. This segmentation allows servicing without complete disassembly, reducing complexity and time while maintaining accessibility to sealing components.

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If the entire unloader is demounted for servicing, then the sealing components can be replaced, but the physical effort required increases due to the weight of the unloader

Engineering Contradiction:
Improvereplacement of sealing meansVSAvoidweight of unloader
Core Design Contradiction:
Ease of repairVSWeight of moving object

Solution Approach 1:

The lid is designed as a separate, lightweight component that can be removed independently from the housing. Since only the lid needs to be handled during servicing rather than the entire unloader assembly, the physical effort is significantly reduced. The housing remains mounted on the compressor, eliminating the need to move the heavy thirty kilogramme unit.

Inventive Principle:
Principle #1Segmentation

3Ease of repair

If the entire unloader is removed from the compressor for servicing, then the seal and slide ring can be replaced, but the compressor inlet is exposed to dirt and contamination

Engineering Contradiction:
Improveaccess to piston rod componentsVSAvoiddirt entry into compressor
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The lid is designed to seal the cavity containing the piston and sealing components. During servicing, only the lid is removed while the housing remains mounted on the compressor, maintaining the seal at the compressor inlet. This allows access to the piston rod components through the removable lid without exposing the compressor inlet to contamination.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If the seal is installed blindly and using force during reassembly, then the unloader can be reassembled, but the seal may be damaged resulting in inadequate sealing

Engineering Contradiction:
Improvereassembly processVSAvoidsealing quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The cavity is designed to guide the piston and seal into their correct positions during lid reassembly. The sealing surfaces and component geometries are arranged to automatically align the seal properly as the lid is installed, eliminating the need for blind, forceful installation that could damage the seal and compromise sealing quality.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3749860B1Unloader for a compressor and the maintenance thereof and compressor provided with an unloader
Publication Date: 2021.09.08 ATLAS COPCO AIRPOWER NV
  • EP3749860B1 patent drawingFigure 1~2
  • EP3749860B1 patent drawingFigure 3~4

AI summary

Unloader for a compressor, said unloader (1) comprising a housing (2) with an inlet (3) and an outlet (4), and whereby the unloader (1) is further provided with a piston rod (5) which is arranged moveably in a reciprocating manner in the housing (2), whereby on one end (5a) of the piston rod (5) a valve (7) is provided to be able to close the outlet (4) and whereby on the other end (5b) of the piston rod (5) a piston (8) is arranged, the piston being arranged moveably in a reciprocating manner in a thereto provided cavity (9) of the unloader (1), said cavity (9) being at least partially delimited by a lid (10) which is provided on the housing (2) and which is also part of the unloader (1), whereby sealing means (11) are provided for the leakage-free movement of the piston (8) in said cavity (9), whereby the cavity (9) in which the piston (8) is arranged moveably in a reciprocating manner is provided at least partially in the lid (10).