Triangular Strainer Front End Prevents Urea Blow-Back
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Solution Overview
Problem
In urea-SCR systems, the removal of dust from the urea aqueous solution tank is costly and time-consuming, and existing filters often result in the possibility of blow-back of the urea aqueous solution during maintenance.
Innovation Solution
A tank with a strainer having a cylindrical shape and a front end portion with a triangular or trapezoidal cross-section, formed from a material that prevents liquid passage, is integrated into the injection pipe to prevent blow-back by allowing the urea aqueous solution to flow out from the side surface, thereby preventing return flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is provided in the urea aqueous solution tank to remove dust, then dust removal effectiveness is improved, but the risk of blow-back during maintenance increases
Solution Approach 1:
The filter structure is segmented into a cylindrical strainer body with a screen portion and a separate front end portion with triangular or trapezoidal cross-section. This segmentation allows the liquid flow to be divided: entering through the front end, filtering through the screen, and exiting through the rear end, preventing direct backflow while maintaining filtration effectiveness
Solution Approach 2:
The front end portion is designed with an asymmetric triangular or trapezoidal cross-section rather than a symmetric cylindrical shape. This asymmetric geometry creates a one-way flow path that allows liquid to enter and pass through the screen but prevents liquid from flowing backward, thereby eliminating blow-back risk while maintaining dust removal capability
2Reliability
If a conventional filter is used in the injection pipe, then dust removal is achieved, but device complexity and maintenance cost increase
Solution Approach 1:
The filter function is merged with the injection pipe structure itself. The strainer body with screen portion and front end portion is integrated directly into the injection pipe, eliminating the need for separate filter components and reducing overall device complexity while maintaining effective dust removal
Solution Approach 2:
The strainer assembly serves multiple functions: it acts as both a filtration device for dust removal and as part of the injection pipe structure. The front end portion with its unique geometry simultaneously provides flow direction control and prevents blow-back, combining multiple functions in a single integrated component
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 solution effectively prevents blow-back of the urea aqueous solution, reducing the frequency of filter replacements and ensuring reliable operation by ensuring the urea aqueous solution flows out without returning, thus maintaining system efficiency.
Implementation Method 1
a screen portion (234) formed using a mesh material and covering the inner surface of the strainer body (23a)
Implementation Method 2
the front end portion (23b) is formed using a material through which the liquid cannot pass
Data Source
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AI summary
The present invention makes it possible to prevent blow-back of a urea aqueous solution. A strainer is provided in an interior of an injection pipe serving as an injection opening through which a liquid containing a reducing agent is injected into a tank body. In the strainer, a front end portion, having a substantially triangular or substantially trapezoidal shape when a cross section is taken along a plane including an axis of a strainer body having a substantially cylindrical shape, is formed integrally with a front end of the strainer body.