Centrifugal Separator Disc Stack Compression During Bowl Assembly

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Solution Overview

Problem

The existing methods for mounting a stack of separating discs in a centrifugal separator bowl require significant effort due to friction between the bowl hood and the discs, as well as increasing compression forces, making it difficult to compress the disc stack effectively.

Innovation Solution

A method involving a compression tool with a screw and nut system that pre-compresses the disc stack before mounting the bowl hood, allowing for easier assembly by lifting the distributor to an upper position and securing it with a predetermined torque, followed by final compression with a lock ring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bowl hood is screwed onto the bowl body to compress the disc stack, then the separation efficiency is improved, but the mounting effort increases due to friction and compression forces

Engineering Contradiction:
Improveseparation efficiencyVSAvoidmounting effort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by pre-compressing the disc stack using a compression tool before mounting the bowl hood. The compression tool includes a support with a screw that presses against the top disc, compressing the entire stack beforehand. This preliminary compression eliminates the need to overcome high friction and compression forces during bowl hood mounting, as the discs are already in their compressed position. The bowl hood can then be easily screwed onto the bowl body without encountering resistance from uncompressed discs.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the disc stack is compressed during bowl hood mounting, then the leakage between discs is prevented, but the mounting process becomes difficult

Engineering Contradiction:
Improveleakage preventionVSAvoidmounting difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention resolves this contradiction by performing the compression action beforehand using a dedicated compression tool. The tool's support with screw mechanism compresses the disc stack to the required degree before the bowl hood is attached. This ensures that when the bowl hood is mounted, the discs are already compressed and positioned correctly, preventing leakage while avoiding the difficulty of compressing them during the mounting process itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The compression tool acts as an intermediary device between the disc stack and the bowl hood mounting process. It provides a controlled compression mechanism that independently compresses the discs before the final assembly is completed. The support with screw and nut mechanism serves as a mediator to achieve the desired compression state without directly involving the bowl hood threading, thus separating the compression function from the mounting operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 simplifies the mounting process by reducing the effort required to compress the disc stack, ensuring proper contact and compression without excessive force, thereby enhancing separation efficiency in centrifugal separators.

Implementation Method 1

a compression tool comprising a support having a centre axis, a screw supported coaxially with said centre axis in said support, and a nut threaded onto a first threaded end of said screw and adapted to be resting against a first end of said support, with a second end of said support on said bowl hood or a neck ring attached to said bowl hood

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

this is obtained with effort since the friction between the under-side of the bowl hood and the top disc counteract the mounting of the bowl hood as does the increasing compression forces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

tightening said nut with a pre-determined torque, in relation to said first threaded end of said screw in such a manner that said distributor is lifted to an upper position

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 4

In a centrifugal separator for separation of a liquid mixture into at least one heavy phase and one light phase having a relative lower density than said heavy phase

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3825010B1Method for mounting a stack of separating discs in a centrifugal separator bowl and a tool
Publication Date: 2022.06.22 ALFA LAVAL CORP AB
  • EP3825010B1 patent drawingFigure 1
  • EP3825010B1 patent drawingFigure 2
  • EP3825010B1 patent drawingFigure 3

AI summary

Method for mounting a stack 13 of separating discs in a centrifugal separator bowl 18 comprising a bowl body 5 and a bowl hood 6, the method comprising steps of: a) mounting and securing said stack 13 of separating discs on a distributor 19; b) placing and rotatably fixing said distributor 19 in said bowl body 5; c) mounting said bowl hood 6 on said bowl body 5; d) arranging a compression tool 201 for compressing said stack 13 of separating discs, said compression tool 201 comprising a support 202' having a centre axis X, a screw 207 arranged coaxially with said centre axis X in said support 202', and a nut 215 threaded onto a first threaded end 208 of said screw 207 and adapted to be resting against a first end 203 of said support 202', with a second end 205 of said support 202' resting axially on said bowl hood 6 or a neck ring 27 attached to said bowl hood 6 and said screw 207 extending into a central through-hole 8 in said bowl hood 6; e) fastening said screw 207 with a second threaded end 209 in a first threading 214 of said distributor 19; f) tightening said nut 215, in relation to said first threaded end 208 of said screw 207 in such a manner that said distributor 19 is lifted to an upper position; g) fixing said distributor 19 in its upper position; h) dismounting said compression tool 201. A compression tool for performing the method comprises a support, a screw and a nut in accordance to above. A centrifugal separator kit comprises a centrifugal separator and said compression tool.