Gate Valve Sealing System with Thermoplastic and Elastomeric Inserts
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Solution Overview
Problem
Existing sealing systems for industrial gate valves, particularly those using thermoplastic materials, face issues with optimal sealing at high pressures, wear, deformation, and increased manufacturing costs due to metal-to-metal contact and the need for precise machining, as well as reliability concerns under high fluid pressures and potential contamination.
Innovation Solution
A sealing system incorporating a thermoplastic insert and an elastomeric rubber sealing member, such as an o-ring or delta ring, combined with a scraper ring, which ensures effective sealing at pressures up to 150 bars or more, reduces manufacturing costs, and minimizes the risk of metal-to-metal contact and contamination, while requiring less torque for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermoplastic insert is used for sealing between the seat and the slab, then the valve can operate with reduced manufacturing costs and simpler machining, but the sealing becomes suboptimal at high pressures and the insert is subject to wear and deformation
Solution Approach 1:
The patent employs a composite sealing system combining a thermoplastic insert (for cost-effectiveness and basic sealing) with an elastomeric rubber member (for enhanced sealing at high pressures). This composite approach allows the valve to benefit from both the manufacturing advantages of thermoplastic materials and the high-pressure sealing capabilities of elastomeric materials, resolving the contradiction between manufacturing ease and sealing reliability.
2Device complexity
If metal-to-metal contact is used for seat sealing, then the valve structure is simpler and manufacturing is easier, but the high pressure causes definitive seizing of the valve with irreparable damage
Solution Approach 1:
The patent introduces a thermoplastic insert as an intermediary layer between the metal seat and the metal slab. This intermediary prevents direct metal-to-metal contact, thereby eliminating the risk of seizing and irreparable damage while maintaining a relatively simple sealing structure. The thermoplastic material acts as a protective mediator that absorbs the high pressures without causing metal galling or seizing.
3Manufacturing precision
If the slab surface is accurately machined and lapped to achieve good sealing with thermoplastic material, then the sealing quality improves, but the production costs increase significantly
Solution Approach 1:
The patent segments the sealing function into two parts: the thermoplastic insert provides the primary sealing interface with the slab, while the elastomeric rubber member provides the secondary sealing interface with the seat. This segmentation allows the slab surface to be machined to standard tolerances rather than requiring expensive lapping operations, as the thermoplastic insert compensates for surface irregularities.
4Ease of manufacture
If a thermoplastic insert is used for sealing, then the valve can handle normal pressures, but the sealing is not reliable at high fluid pressure values exceeding 55 bars due to wear and deformation
Solution Approach 1:
The patent uses a composite sealing system where the thermoplastic insert handles normal operating pressures and the elastomeric rubber member is specifically designed to engage and provide reliable sealing at high pressures exceeding 55 bars. The elastomeric material's flexibility and pressure-resistance properties complement the thermoplastic insert, enabling the valve to withstand high fluid pressures without sealing failure.
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 system provides reliable and cost-effective sealing at high pressures, reduces the risk of valve seizing, and allows for the use of less powerful actuators, enhancing operational and manufacturing efficiency while maintaining valve integrity.
Implementation Method 1
at least one sealing member made of elastomeric material suited to achieve the fluid sealing between said seat and the slab of said valve
Implementation Method 2
a sealing member made of thermoplastic material works between the seat and the slab, which is suited to ensure the sealing of the valve while being suited to allow the relative movement between seat and slab
Data Source
AI summary
The present invention concerns a sealing system particularly for industrial safety valves, even more particularly for industrial gate valves. Hence, the subject of the present invention is both a sealing system (1) suited to be used on a gate valve and a gate valve comprising such a sealing system (1). The system according to the present invention allows to combine the advantages in terms of simplicity and cost-effectiveness for manufacturing gate valves provided with a traditional sealing system, with further advantages in terms of performance both at high and at low operating pressures and reducing the torques required to handle the slab, also ensuring the operation of the valve itself with unaltered sealing performance over time, even under particular and demanding operating conditions.