Knife Gate Valve Seat Locking for Reverse Pressure Stability
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Solution Overview
Problem
Conventional resilient seated knife gate valves face issues with positive securing, high machining costs, difficult assembly and replacement, instability under reverse pressure or horizontal orientations, and temperature limitations.
Innovation Solution
A knife gate valve design featuring an annular groove with a stepped surface and locking surfaces, which allows a resilient seat ring with a wedge to self-lock within the groove, eliminating the need for additional retaining devices and enabling secure operation under various orientations and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional molded plastic seats are used with pins or retaining devices, then the seat can be retained in the valve body, but the seat is not positively secured and may move out of position under reverse pressure or horizontal orientations
Solution Approach 1:
The annular groove is segmented into multiple functional zones: an insertion portion for easy installation, a stepped surface for positioning, and locking surfaces that engage with the resilient seat. This segmentation allows each portion to perform its specific function independently, achieving positive securing without complex retaining devices
Solution Approach 2:
The resilient seat itself performs the locking function through its elastic properties. When inserted into the annular groove, the resilient material deforms and automatically locks into the groove's locking surfaces, eliminating the need for external retaining devices. The seat self-secures under reverse pressure and in horizontal orientations
2Reliability
If additional retaining devices such as pins, screws, or O-rings are used to secure the seat, then the seat can be retained, but the machining cost increases and assembly becomes more difficult
Solution Approach 1:
The retaining function is merged into the valve body structure itself through the annular groove. The groove integrates multiple functions (retention, positioning, locking) into a single structural feature, eliminating the need for separate retaining components and reducing machining steps
Solution Approach 2:
The complex retaining devices (pins, screws, O-rings, welding operations) are extracted from the design. Only the essential annular groove remains, which can be machined in a single operation, significantly reducing manufacturing cost and assembly difficulty
3Ease of repair
If conventional molded plastic seats are used, then the seat can be installed, but replacement becomes difficult and requires multiple components
Solution Approach 1:
The seat and groove are designed as separate, independent components. The annular groove remains in the valve body while the resilient seat can be independently removed and replaced. This segmentation allows for simple replacement of just the seat without affecting other components
Solution Approach 2:
All retaining components (pins, retaining rings, fasteners) are extracted from the design. The resilient seat is held solely by the annular groove, which can be easily accessed and the seat removed from, simplifying replacement to a single-component operation
4Reliability
If elastomeric materials are used for the resilient seat, then sealing is effective, but temperature is constrained to below 150 degrees Celsius
Solution Approach 1:
The patent utilizes resilient materials with enhanced temperature resistance, combining the sealing effectiveness of elastomeric materials with improved thermal stability. The resilient seat material is selected to maintain elastic properties at higher temperatures, enabling operation beyond the 150°C limit of conventional elastomers
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 solution provides a cost-effective, easily assembled, and replaceable resilient seat that can withstand reverse pressure, horizontal orientations, and higher temperature ranges, improving the operational reliability and ease of maintenance of knife gate valves.
Implementation Method 1
The wedge is installed past the stepped surface of the annular groove... the first locking surface and second locking surface are configured to abut
Implementation Method 2
The resilient seat ring has a wedge defining a sloped surface... wherein the wedge is installed past the stepped surface of the annular groove
Data Source
AI summary
The embodiments disclosed herein relate to a knife gate valve having a valve body which defines a bore, and a gate for the bore, and having: an interior surface of the valve body; an annular groove defined entirely within the interior surface; a stepped surface and a first locking surface defined in and of the annular groove, wherein the first locking surface is adjacent and contiguous to the stepped surface; a resilient seat ring inserted into the annular groove, wherein the resilient seat ring has a wedge defining a sloped surface, and wherein the wedge is installed past the stepped surface of the annular groove; a second locking surface defined on the resilient seat, wherein the second locking surface is adjacent and contiguous to the sloped surface; and further wherein the first locking surface and second locking surface are configured to abut.