Bell Joint Injection for Corrugated Pipe Sealing
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Solution Overview
Problem
The formation of bell joints in corrugated pipes is hindered by deformation of ribbings and plastic memory in polyolefins, leading to incomplete seals due to incorrect gasket insertion and manual difficulties, especially in high diameters, where dirt accumulation and manual effort are significant issues.
Innovation Solution
The method involves producing an external sleeve by injection that adheres to and welds with the pipe, containing a circumferential gasket seat on its inner surface, allowing for stable bell joint formation without deformed ribbings, with the gasket inserted during the process using a shared mould to simplify and expedite the operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If hot plastic deformation is used to form the bell, then the pipe can be shaped with an external sleeve, but the ribbings deform and plastic memory causes the material to return towards the original position
Solution Approach 1:
The invention performs preliminary actions by pre-forming the bell shape and pre-installing the gasket during the injection molding process, before final assembly. This prevents subsequent deformation issues and ensures proper gasket positioning while the material is still pliable.
Solution Approach 2:
The invention changes the temperature and pressure parameters during injection molding to control the plastic deformation process. By optimizing these parameters, the bell is formed with minimal ribbings deformation and the plastic memory effect is managed through controlled cooling rates.
2Reliability
If a gasket ring is added in the external sleeve seat, then sealing is improved, but manual insertion is difficult and requires considerable effort especially for high diameters
Solution Approach 1:
The injection molding machine performs the gasket installation automatically as part of the bell formation process. The system serves itself by integrating the gasket placement operation into the existing molding cycle, eliminating the need for separate manual installation steps.
Solution Approach 2:
The invention merges the bell formation and gasket installation into a single integrated process. Both operations are performed simultaneously during injection molding, combining what were previously separate manual operations into one automated process step.
3Adaptability or versatility
If the gasket is inserted manually, then flexibility is maintained, but dirt accumulation in the gasket spaces hinders the operation and may cause incorrect insertion
Solution Approach 1:
The invention replaces the manual mechanical insertion process with an automated injection system. This substitution eliminates the problems of dirt accumulation and incorrect insertion by using a controlled, clean environment during the molding process, while still maintaining flexibility through programmable positioning.
4Stability of the object's composition
If the external sleeve is formed by injection during the forming process, then the bell shape remains stable and ribbings do not deform, but the process complexity increases
Solution Approach 1:
The injection molding apparatus performs multiple functions: forming the bell shape, creating the external sleeve, and installing the gasket all in one operation. This multi-functionality justifies the increased device complexity by consolidating what would otherwise require multiple separate processes and manual operations.
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 method ensures a dimensionally stable bell joint with improved sealing and reduced manual effort, allowing for efficient production of corrugated pipes with enhanced sealing performance and reduced material deformation, facilitating the use of various rubber materials for optimal sealing.
Implementation Method 1
the external sleeve of the joint is produced by means of injection during the process of forming, in such a way that it can adhere to and weld with the corresponding axial edge of the pipe
Implementation Method 2
adhere to and weld with the corresponding axial edge of the pipe
Implementation Method 3
insertion by injection in its seat of the sleeve and already in work position the sealing gasket
Implementation Method 4
providing a method for producing a bell joint for corrugated pipes, including a seal
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a system of production of a joint of the bell type for corrugated pipes in plastic material, preferably in polyolefins, comprising in a first working phase an appropriate processing of an axial end of normal pipe; in a second phase the injection by means of plastic material, at said end, of the external joint part shaped with a sleeve, mainly of cylindrical shape on its inner surface, of appropriate diameter but in any case greater than the outside one of the coupled pipe; moreover, it being possible to weld said sleeve at the time of injection, on the circumference of the processed end of the pipe, as above, and being coaxial thereto; an annular seat, designed to contain the sealing gasket of the joint, being moreover formed, in the operation of injection, in an appropriate position of the inner surface of the sleeve, as above; said system then comprising in a third phase the injection of the same sealing gasket, made in a suitable elastic material and in an appropriate shape, directly in the aforesaid seat of the sleeve, and placed already in a work position.