Bottom Entry Plastic Ball Valve Bottom Cover Design
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Solution Overview
Problem
Traditional plastic ball valves face manufacturing and assembly difficulties due to complex processes, high costs, and inaccuracies in sealing ring placement and pre-stressed force control, leading to potential leakage and excessive torque.
Innovation Solution
A bottom entry plastic ball valve design with a valve bottom cover hole below the ball chamber for direct mounting of sealing rings, using end surface welding instead of electric fusion welding, allowing for accurate control of sealing ring distance and pre-stressed force through hot melt welding, eliminating the need for complex electric fusion welding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electric fusion welding is used for large-diameter ball valves, then manufacturing precision and sealing reliability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The valve body is divided into upper and lower parts with a bottom cover hole, allowing sealing rings to be installed separately at the bottom rather than requiring complex fusion welding of the entire assembly. This segmentation enables simplified hot melt welding while maintaining precision.
Solution Approach 2:
The bottom cover hole acts as an intermediary structure that facilitates the installation of sealing rings and supporting rings. This intermediate feature enables precise positioning and simplified welding by providing a dedicated installation path separate from the main valve body fusion welding.
2Device complexity
If hot melt welding is used for large-diameter ball valves, then device complexity and manufacturing cost are reduced, but manufacturing precision and sealing reliability deteriorate
Solution Approach 1:
The bottom cover hole is pre-formed in the valve body before final assembly. This preliminary action allows sealing rings and supporting rings to be pre-positioned with high precision through the bottom cover hole, ensuring accurate placement before the hot melt welding process is completed.
Solution Approach 2:
The complex electric fusion welding mechanical system is replaced with a simpler hot melt welding process. The bottom cover hole structure compensates for the reduced precision of hot melt welding by providing a guided installation path for sealing components, ensuring accurate positioning without requiring complex welding equipment.
3Ease of manufacture
If traditional side-entry structure is used, then ease of manufacture is improved, but sealing reliability and pre-stressed force control deteriorate
Solution Approach 1:
Instead of the traditional side-entry structure where sealing rings are installed from the side, this invention inverts the approach by installing sealing rings from the bottom through the bottom cover hole. This inverted installation method provides better control over sealing ring positioning and pre-stressed force application, improving sealing reliability while maintaining manufacturing simplicity.
Solution Approach 2:
The sealing ring installation is moved from the horizontal side-entry dimension to the vertical bottom-entry dimension. This dimensional change allows for better gravitational assistance during assembly and more uniform distribution of pre-stressed force on the sealing surfaces, enhancing sealing reliability.
4Reliability
If large insertion depth of connecting pipe is used, then sealing pre-stressed force is improved, but torque and abrasion increase
Solution Approach 1:
The function of creating sealing pre-stressed force is extracted from the connecting pipe insertion depth and transferred to the bottom cover hole structure and ring assembly mechanism. This allows adequate pre-stressed force to be achieved through the bottom-up assembly approach without requiring excessive inserting depth, thereby reducing operating torque and abrasion.
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 design simplifies the manufacturing process, reduces costs, and ensures accurate control of pre-stressed force and torque, minimizing leakage risks and improving the overall performance of large-diameter ball valves.
Implementation Method 1
the inner cylindrical surface of the insertion-accepting part of the valve body and the outer cylindrical surface of the connecting pipe are heated and molten on a hot melting machine, and when the two cylindrical surfaces are molten to a certain thickness, the connecting pipe is inserted into the insertion-accepting part of the valve body to a certain depth and gradually cooled by keeping pressure
Implementation Method 2
the valve bottom cover can cover the valve bottom cover hole and can be fusion-bonded to the valve body
Data Source
AI summary
A bottom entry plastic ball valve comprises a valve stem cap (1), a valve stem (2), a valve stem sealing ring (3), a valve stem end surface sealing ring (4), a valve ball sealing ring (5), a supporting ring (6) for the valve ball sealing ring, a valve ball (7), a connecting pipe (8), and a valve body (9). A hollow valve ball chamber (911) is provided inside the valve body (9), the valve body (9) is provided with a valve bottom cover hole (912) just below the valve ball chamber (911), and the width of the valve bottom cover hole (912) is larger than the diameter of the valve ball (7). The ball valve also comprises a valve bottom cover (10) corresponding to the valve bottom cover hole (912) so that the valve bottom cover (10) can cover the valve bottom cover hole (912) and can be fusion-bonded to the valve body (9), thereby avoiding the need for electric fusion welding in the manufacture of large-diameter ball valves.