Polyethylene Pipe Butt Fusion With Calculated Cooling Time
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Solution Overview
Problem
The existing butt-fusion process for joining polyethylene pipes is inefficient due to conservative cooling time requirements, which lead to extended idle periods for the heat fusion apparatus, affecting the overall efficiency and cost of pipe line formation.
Innovation Solution
A method that calculates a minimum cooling time based on the wall thickness, bulk temperature, and heat soak time using a predictive formula, allowing for the release of interfacial pressure and safe handling of the joint, significantly reducing the cooling time required before the joint can be safely handled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conservative cooling time requirement (11 minutes per inch of wall thickness) is followed, then the joint strength and reliability are ensured, but the productivity and efficiency of the pipe line formation process deteriorate due to extended idle time
Solution Approach 1:
The patent applies parameter changes by transitioning from a fixed conservative cooling time parameter to a dynamic calculated cooling time parameter. The cooling time is determined by the formula t = k × (t1 - t2) × (t3/60), where k is an empirical constant, t1 is the heat soak temperature, t2 is the ambient temperature, and t3 is the heat soak time. This parameter-based approach allows optimization of cooling time while ensuring joint strength, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent implements self-service by using the process parameters themselves (temperatures, times) to determine the cooling time requirement. The system calculates the minimum cooling time based on the actual thermal conditions of the specific joint being formed, eliminating the need for external conservative estimates and enabling efficient scheduling of the heat fusion apparatus.
2Reliability
If the conservative cooling time is used, then the effects of ambient temperature, bulk pipe temperature, and heat time variables are accounted for, but the loss of time and waiting period increases substantially
Solution Approach 1:
The patent transforms the cooling time determination from a fixed conservative value to a calculated value based on actual process parameters. By incorporating ambient temperature (t2), bulk pipe temperature (t1), and heat soak time (t3) into the calculation formula, the system dynamically adjusts cooling time to match actual thermal conditions, reducing unnecessary waiting time while ensuring adequate cooling.
Solution Approach 2:
The patent applies feedback by using the measured or controlled process parameters (heat soak temperature, ambient temperature, heat soak time) to determine the appropriate cooling time. This feedback loop ensures that the cooling time is directly related to the actual thermal state of the joint, preventing both under-cooling and excessive waiting time.
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 approach shortens the cooling time, enabling the heat fusion apparatus to be used more efficiently, reducing waiting times and costs associated with the pipe line formation process while ensuring the joint's strength for safe handling.
Implementation Method 1
heated so that the molten PE material bonds the pipe e ends together into a fused joint
Implementation Method 2
the molten PE material bonds the pipe e ends together
Implementation Method 3
the required cooling time of a butt-fused joint
Data Source
AI summary
A method for minimizing the time to form a polyethylene pipe e joint comprises the steps of performing a butt-fusion process until the beginning of the full cooling cycle; holding an interfacial pressure through a minimum cool time calculated using a formula based on the wall thickness of the pipe e, the initial bulk temperature of the pipe e, and a heat soak time; and releasing the interfacial pressure from the fused pipe e joint at the end of the calculated minimum cool time.