Steel Elbow Polyethylene Coating Sealing for Continuous Spraying
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Solution Overview
Problem
Existing anti-corrosion coating technologies for steel elbows in long-distance oil and gas pipelines face issues with intermittent operation, low efficiency, and leakage due to insufficient sealing between inner and outer rings, leading to polyethylene overflow and waste.
Innovation Solution
A multiple sealing structure is implemented using wear-resistant materials and high-temperature gas sealing, combined with a gear transmission and L-shaped labyrinth sealing, to prevent polyethylene overflow during continuous spraying on steel elbows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single sealing structure is used between inner and outer rings, then the device complexity is low, but polyethylene overflow occurs and sealing reliability is insufficient
Solution Approach 1:
The sealing structure is divided into multiple independent sealing rings (first sealing ring, second sealing ring, third sealing ring) arranged in sequence between the inner and outer rings. Each sealing ring provides an additional sealing barrier, preventing polyethylene overflow through multiple layers of protection rather than relying on a single sealing point.
Solution Approach 2:
The sealing rings are nested within the annular space between the inner and outer rings, with each sealing ring positioned concentrically. The first sealing ring is closest to the inner ring, followed by the second sealing ring, and then the third sealing ring nearest to the outer ring, creating a nested sealing configuration that maximizes space utilization and sealing effectiveness.
2Productivity
If intermittent spraying is used for polyethylene coating, then the device complexity is low, but productivity is reduced and coating quality is compromised
Solution Approach 1:
The material conveying channels are designed to enable continuous flow of molten polyethylene from the extruder through the first material conveying channel, into the annular space between inner and outer rings, and through the second material conveying channel to the spraying head. This continuous material supply system eliminates intermittent operation, allowing uninterrupted spraying and significantly improving productivity.
Solution Approach 2:
The molten polyethylene is prepared and conveyed through the first material conveying channel in advance before reaching the spraying point. The material is pre-positioned in the annular space between the inner and outer rings, ensuring that spraying can proceed continuously without waiting for material replenishment, thereby maintaining high productivity.
3Loss of substance
If high-temperature molten polyethylene is conveyed through a single channel, then the device complexity is low, but material loss occurs due to overflow and sealing failure
Solution Approach 1:
The material conveying system is segmented into the first material conveying channel for supplying molten polyethylene to the annular space, and the second material conveying channel for delivering material from the annular space to the spraying head. This segmentation allows for controlled material flow and prevents overflow at critical interfaces, reducing material loss.
Solution Approach 2:
The annular space between the inner and outer rings serves as an intermediary chamber that receives molten polyethylene from the first material conveying channel and transfers it to the second material conveying channel. This intermediary space acts as a buffer zone that stabilizes material flow and prevents direct exposure to potential overflow points, thereby reducing material waste.
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
Ensures effective continuous spraying of polyethylene without overflow, improving efficiency and reducing waste by maintaining stable sealing performance.
Implementation Method 1
a high-temperature gas sealing structure is arranged on the outside of the first sealing structure... sealing by high-temperature gas
Implementation Method 2
the first sealing structure is made of wear-resistant materials
Implementation Method 3
L-shaped labyrinth sealing
Data Source
AI summary
The present disclosure discloses equipment for preparing a polyethylene coating with a three-layer structure wound on a steel elbow, belonging to the technical field of anti-corrosion pipe production equipment. The equipment including a material conveying mold for conveying molten polyethylene, the material conveying mold includes a static mold and a rotary mold which are rotationally connected, and a first material conveying channel is formed in the static mold, a second material conveying channel is formed in the rotary mold, a material outlet port of the first material conveying channel is coaxially communicated with a material inlet port of the second material conveying channel, a first sealing structure and a second sealing structure are arranged at the communication position around the axis from inside to outside at intervals, the first sealing structure is made of wear-resistant materials, and the second sealing structure is sealed by high-temperature gas.