Wash Nozzle Assembly With Trailing Edge Orifice Plate

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Solution Overview

Problem

Existing wash nozzles in atmospheric diffusers are prone to clogging due to pulp fibers, leading to inefficient wash water distribution and increased downtime for cleaning, with limited ability to prevent pulp entry and requiring complex cleaning processes.

Innovation Solution

The wash nozzle assembly features an orifice plate located at the trailing edge of the nozzle, equipped with a non-return device such as a lip-type non-return device or perforated plate, which prevents pulp fibers from entering while allowing wash liquid to flow effectively into the pulp, and allows for easy detachment and cleaning of orifice plates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the orifice plate is located between the nozzle and nozzle arm, then the wash filtrate flow can be controlled, but the nozzle becomes susceptible to clogging by pulp fibers

Engineering Contradiction:
Improvewash filtrate flow controlVSAvoidnozzle clogging resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The orifice plate is inverted to a perpendicular orientation at the trailing edge of the nozzle, changing the flow direction from axial to lateral. This inversion prevents pulp fibers from entering the nozzle while maintaining wash filtrate flow control through the orifice opening.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The perpendicular orifice plate acts as an intermediary element that selectively allows wash filtrate to pass through while blocking pulp fibers. The plate serves as a mediator between the wash water supply and the pulp mass, enabling controlled liquid flow without fiber contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the wash filtrate flow velocity is reduced, then the nozzle can distribute wash liquid more evenly, but the nozzle becomes more susceptible to clogging by fibers

Engineering Contradiction:
Improvewash liquid distribution uniformityVSAvoidnozzle clogging resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

By inverting the orifice plate to a perpendicular orientation, the flow pattern changes from a concentrated axial jet to a distributed lateral flow. This allows even wash liquid distribution across the screen area while the perpendicular plate geometry maintains resistance to fiber clogging even at reduced flow velocities.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If the nozzle rotates at high velocity, then the wash liquid can be distributed more effectively, but the nozzle sucks pulp into it causing clogging

Engineering Contradiction:
Improvewash liquid distribution efficiencyVSAvoidnozzle clogging resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The perpendicular orifice plate orientation creates a flow pattern that is resistant to the suction effect generated by high-velocity rotation. The lateral flow path through the perpendicular plate prevents pulp from being drawn into the nozzle while maintaining effective wash liquid distribution across the screen area.

Inventive Principle:
Principle #13The other way round (Inversion)

4Ease of repair

If the orifice plate is made detachable, then the cleaning operation becomes easier and faster, but the device complexity increases

Engineering Contradiction:
Improvenozzle cleaning easeVSAvoidnozzle assembly complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The nozzle assembly is segmented into detachable components, with the orifice plate separable from the nozzle body. This segmentation allows the orifice plate to be easily removed for cleaning or replacement without disassembling the entire nozzle assembly, significantly improving maintenance ease while adding minimal complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The orifice plate is extracted as a separate, removable component from the nozzle assembly. This extraction allows the critical filtering element to be independently accessed, removed, and cleaned, simplifying the maintenance process and reducing downtime without substantially increasing overall device complexity.

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 design ensures even wash liquid distribution, reduces clogging, and significantly decreases downtime by maintaining nozzle cleanliness and simplifying the cleaning process, enhancing washing efficiency and availability of the diffuser.

Implementation Method 1

equipped with a non-return device such as a lip-type non-return device or perforated plate, which prevents pulp fibers from entering while allowing wash liquid to flow effectively into the pulp

Methodology Applied
Scientific EffectNon-return device: Valve

Implementation Method 2

The orifice plate/orifice assembly is preferably located at the trailing edge. It may also be located at the leading edge, in which case a shielding element is needed in front of the leading edge so that the pulp flowing against the nozzle will not prevent the liquid outflow from the nozzle.

Methodology Applied
Scientific EffectFluid flow through orifice: Pressure Gradient

Data Source

PatentEP3802948B1Wash nozzle assembly for atmospheric diffusers in pulp production
Publication Date: 2023.02.22 ANDRITZ OY
  • EP3802948B1 patent drawingFigure 1~2
  • EP3802948B1 patent drawingFigure 3~6
  • EP3802948B1 patent drawingFigure 7~8

AI summary

The invention relates to a wash nozzle assembly for all types of atmospheric diffusers for washing cellulose pulp. The nozzle assembly comprises a nozzle 5 which has a wash flow controlling orifice plate or another orifice assembly, preferably located at the trailing edge of the nozzle.