Heated Pipe-Lining Pig With Diffuser for Uniform Thermoplastic Melting
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Solution Overview
Problem
Existing duct lining systems face limitations in achieving uniform heating of thermoplastic materials within fabric sleeves, leading to potential cold and hot spots, which can result in incorrectly formed or weak duct liners due to restricted pig length and non-uniform air delivery.
Innovation Solution
A pig design featuring a cylindrical heating chamber with coiled heating elements, a tree diffuser for gas distribution, and an outlet diffuser with vanes to ensure uniform gas flow and improved heating efficiency, along with baffles to direct gas flow across the heating coils, enhancing the uniformity and effectiveness of thermoplastic material melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pig length is limited to around 700mm for practical navigation, then the pig can navigate curves in the pipe, but the space available for heating air to sufficient temperature is restricted
Solution Approach 1:
The heating chamber is segmented into multiple zones with heating elements arranged in sections along the pig body. This allows the limited space within the 700mm pig to be efficiently utilized by distributing heating capacity across multiple smaller heating zones rather than requiring a single large heating chamber.
2Ease of operation
If the pig length is limited to around 700mm, then the pig can navigate curves in the pipe, but uniform heating of the fabric sleeve becomes difficult to achieve
Solution Approach 1:
Heating elements are distributed at multiple locations along the pig body, with different heating zones targeted at specific sections of the fabric sleeve. The outlet diffuser is designed with varying aperture sizes and distributions to deliver heat locally where needed, ensuring uniform overall heating despite the compact pig length.
Solution Approach 2:
An outlet diffuser is introduced as an intermediary component between the heating chamber and the fabric sleeve. This diffuser distributes the heated air uniformly across the sleeve surface, compensating for the limited heating space within the pig by creating a controlled heat distribution pattern.
3Temperature
If heating air to high temperature is achieved, then thermoplastic material melting is facilitated, but cold and hot spots occur in the fabric sleeve
Solution Approach 1:
The outlet diffuser acts as a heat distribution intermediary that receives high-temperature air from the heating chamber and redistributes it uniformly across the fabric sleeve. The diffuser's aperture design breaks up concentrated heat streams into multiple smaller flows, eliminating hot spots while maintaining sufficient temperature for melting.
Solution Approach 2:
The system changes the temperature distribution parameters by using multiple heating zones at different temperature levels rather than a single high-temperature zone. This allows the thermoplastic material to melt uniformly as different sections receive appropriately tailored heat inputs.
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 enables uniform heating of thermoplastic materials within ducts, preventing cold and hot spots, thus ensuring a correctly formed and robust duct liner with improved structural integrity.
Implementation Method 1
a heating chamber (17) within which is housed a heater (16)
Implementation Method 2
heats the liner sleeve in situ to melt thermoplastic material of the liner sleeve
Implementation Method 3
melt thermoplastic material of the liner sleeve to subsequently form, on cooling of the melted thermoplastic material
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3b
AI summary
The present invention relates to a pig for use in a system for lining ducts such as water or sewage pipes or electrical ducts or gas pipes. The pig is insertable at least partly within a fabric liner sleeve located in a duct such as a water or sewage pipe and is capable of heating the liner sleeve in situ in the duct to melt or soften thermoplastic material of the liner sleeve to subsequently form, on cooling of the melted thermoplastic material, a rigid liner in the duct. A pig for fitting a liner to the inside of a pipe, comprising a pig body defining a longitudinal axis in a longitudinal direction from a front portion to a rear portion; a gas supply port in the front portion; a gas outlet diffuser forming part of the rear portion; a heating chamber in the pig body forming a flow path from the fluid inlet to the outlet diffuser; and a heater within the heating chamber, wherein the outlet diffuser comprises a plurality of channels, each channel comprising an inlet facing the front portion in the longitudinal direction and an outlet extending radially outwardly from the longitudinal axis.