Dry Starch Spray Nozzles for Paper Web Air Cushion Penetration
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Solution Overview
Problem
The challenge in producing paper products is that the application of dry starch is hindered by an air cushion on the surface of the material web, leading to significant losses and inadequate penetration, which reduces the strength of the final product.
Innovation Solution
Applying dry spray starch in powder form using nozzles with a carrier gas at speeds between 0.5 m/s and 3 m/s, allowing the starch to penetrate the air cushion and evenly distribute across the web surface, and potentially electrostatically charging the starch to enhance adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dry starch is applied to the material web surface, then starch penetration and strength improvement are enhanced, but the air cushion on the web surface prevents adequate starch reaching the surface
Solution Approach 1:
The patent uses a carrier gas as an intermediary medium to transport starch particles through the air cushion barrier. The carrier gas creates a controlled flow that carries starch particles across the air cushion interface and delivers them to the web surface, solving the problem of starch inability to penetrate the air cushion.
Solution Approach 2:
The patent applies pneumatic principles by using pressurized carrier gas to propel starch particles through the air cushion. The gas flow dynamics are controlled to ensure particles overcome the air cushion resistance and deposit on the web surface effectively.
2Strength
If aqueous starch suspension is sprayed in the wire section, then starch penetrates the material web and increases internal strength, but starch grains are drawn off with water and burden the wastewater treatment plant
Solution Approach 1:
The patent changes the physical state parameter of starch from aqueous suspension to dry powder form. This parameter change prevents starch from being carried away by water flow, as dry particles can be controlled to penetrate the web structure and remain trapped within the fiber matrix, reducing wastewater contamination.
Solution Approach 2:
The patent replaces the hydraulic delivery system (aqueous suspension through water flow) with a pneumatic delivery system (dry powder through carrier gas). This substitution eliminates the coupling between starch transport and water flow, preventing starch loss in wastewater while maintaining penetration capability.
3Quantity of substance
If starch is applied in powder form, then water content of the web is not increased, but the air cushion prevents adequate starch penetration
Solution Approach 1:
The carrier gas serves as a mediator that bridges the gap between dry starch powder and the web surface through the air cushion. It enables particle transport without requiring water as a vehicle, maintaining low water content while achieving effective starch delivery.
4Manufacturing precision
If spray starch is applied at high speed, then starch distribution across the web surface is improved, but starch may not have sufficient time to hydrate and distribute within the material web
Solution Approach 1:
The patent employs dynamic control of the carrier gas flow velocity to match the web transport speed. This dynamic adjustment ensures particles remain in contact with the web surface long enough for hydration while maintaining uniform distribution across the moving web at high production speeds.
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 method significantly improves the strength parameters of paper products by ensuring a higher proportion of starch reaches the web surface, reducing losses, and allowing for efficient hydration and distribution within the material web, thereby enhancing properties like bursting pressure and surface strength.
Implementation Method 1
dry spray starch is applied to a moving, wet web of material... the starch in powder form is supplied by means of one or more nozzles together with a carrier gas is sprayed onto the damp material web
Implementation Method 2
The web is transported through a drying section... the sprayed solid starch requires a certain amount of time to be wetted, hydrated and suspended or dissolved by the water in the material web
Data Source
AI summary
The invention relates to a method for producing paper, cardboard or paperboard, in which dry spray starch is applied to a running, damp material web and which is characterized in that the starch is sprayed onto the damp material web in a powder form by means of one or more nozzles together with a carrier gas at a speed of at least 0.5 m/s.