Jet box and a dryer using the same
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Solution Overview
Problem
Existing drying technologies for sheet-like products, such as veneer sheets, face inefficiencies in heat transfer due to suboptimal air flow guidance by jet nozzles, leading to increased pressure loss and electricity consumption, and reduced evenness of drying results.
Innovation Solution
A jet box with a novel jet nozzle design featuring a three-dimensional guide surface with a convexly curved first portion and a concavely curved second portion, arranged to guide air flow perpendicularly to the veneer sheet, reducing turbulence and pressure loss while enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple opening or conventional jet nozzle shape is used, then the device complexity is reduced and ease of manufacture is improved, but the heat transfer efficiency decreases and pressure loss increases
Solution Approach 1:
The jet nozzle employs a three-dimensional guide surface with convex and concave curved portions instead of simple flat openings. The curved surfaces guide the air flow more effectively, reducing turbulence and pressure loss while maintaining manufacturing feasibility through standard forming processes.
Solution Approach 2:
The invention optimizes specific geometric parameters of the guide surface including the curvature radii of convex and concave portions, the angle ranges (30-60 degrees for convex, 15-30 degrees for concave), and the ratio between different dimensions to achieve optimal pressure loss reduction and heat transfer efficiency.
2Device complexity
If conventional jet nozzle shapes are used, then the device complexity is reduced, but the heat transfer efficiency and drying evenness deteriorate
Solution Approach 1:
The three-dimensional guide surface with strategically placed convex and concave curved portions redirects air flow more uniformly across the veneer surface, enhancing heat transfer efficiency and drying evenness while adding only moderate geometric complexity to the nozzle design.
Solution Approach 2:
Different portions of the guide surface have different curvature characteristics tailored to specific local requirements: convex portions in certain areas to redirect flow, concave portions in other areas to stabilize flow, creating locally optimized flow patterns that collectively improve overall heat transfer efficiency.
3Speed
If the jet nozzle guides air flow obliquely to the veneer sheet, then the incoming air flow direction changes, but turbulence increases and heat transfer efficiency decreases
Solution Approach 1:
The convex and concave curved surfaces of the guide surface gradually redirect the air flow from its incoming direction to a substantially perpendicular direction relative to the veneer sheet, minimizing flow separation and turbulence that would occur with abrupt directional changes.
Solution Approach 2:
The invention specifies optimal angle ranges for the convex (30-60 degrees) and concave (15-30 degrees) portions of the guide surface to control the air flow turning process, ensuring smooth directional change that maintains kinetic energy and reduces turbulence.
4Volume of stationary object
If dryer size is reduced to lower capital cost, then the investment cost decreases, but the drying capacity and production volume decrease
Solution Approach 1:
By optimizing the geometric parameters of the jet nozzle guide surface, the invention enhances heat transfer efficiency per unit area, allowing smaller dryers to achieve the same production volume as larger conventional dryers, thereby reducing capital costs without sacrificing productivity.
Solution Approach 2:
The improved jet nozzle design accelerates the drying process by enhancing heat and mass transfer rates, allowing the dryer to achieve the required drying capacity in a more compact volume or shorter residence time, effectively skipping the need for oversized equipment.
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
The improved jet nozzle design enhances heat transfer efficiency, reduces pressure loss, and maintains even air flow distribution, allowing for increased production volume with reduced energy consumption and improved drying uniformity.
Implementation Method 1
the first portion of the guide surface substantially on a side of the incoming air flow is convexly curved outwards from the jet box
Implementation Method 2
the second portion of the guide surface substantially on the opposite side of the opening structure in relation to the incoming air flow is concavely curved outwards from the jet box
Implementation Method 3
hot air is blown with circulation blowers against the veneer sheets by means of a jet box
Data Source
AI summary
Disclosed is a jet box for guiding an incoming air flow in drying of a veneer sheet. The jet box includes at least one jet nozzle. The jet nozzle includes a guide surface forming a three dimensional opening structure, which is limited at its first end to an inner opening and at its second end to an outer opening. The guide surface includes a first portion and a second portion, wherein the first portion substantially on a side of the incoming air flow is convexly curved outwards from the jet box and the second portion substantially on the opposite side of the opening structure in relation to the incoming air flow is concavely curved outwards from the jet box. Also disclosed is a dryer including at least one jet box.