Replaceable Hard-Insert Valve Seat for Abrasive Slurry Sealing
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Solution Overview
Problem
Pumps used in abrasive slurries face rapid valve wear and leakage due to particle entrapment between valve disc and seat surfaces, leading to reduced performance, and existing solutions like elastomeric seals are inefficient and prone to wear, especially with conical contact surfaces which increase the risk of particle wedging and pressure imbalances.
Innovation Solution
A valve and valve seat design featuring a disc-shaped element with a spherical surface engaging a toroidal-shaped complementary seat, reducing the contact area to a minimal line of contact, eliminating the need for elastomeric seals, and using replaceable carbide inserts for enhanced sealing and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conical contact surface is used for the valve disc and seat, then the sealing area is increased, but particles can be trapped between the surfaces preventing full closure and causing seal failure
Solution Approach 1:
The patent replaces the conventional conical contact surface with a spherical contact surface on the valve disc that mates with a complementary toroidal (annular) seat. This spherical-toroidal geometry creates a line contact rather than a broad conical contact area, eliminating particle entrapment zones while maintaining sealing effectiveness. The curved spherical surface allows particles to be deflected away from the contact line, preventing the wedging action that occurs with conical surfaces.
2Reliability
If an elastomeric sealing element is used to seal over particles, then sealing is improved, but the seal element wears away over time due to particle entrapment and pressure imbalances
Solution Approach 1:
The patent completely eliminates the elastomeric sealing element from the valve assembly. By using the spherical-toroidal hard surface geometry, the invention achieves sealing through precise line contact between the spherical valve disc surface and the annular toroidal seat, removing the need for separate elastomeric seal components that are susceptible to particle damage and wear.
Solution Approach 2:
The patent employs hard carbide or ceramic materials for both the spherical valve disc contact surface and the annular toroidal seat. These hardened composite materials provide superior wear resistance and durability compared to elastomeric seals, while the specific spherical-toroidal geometry ensures that particles cannot be trapped between the contact surfaces, maintaining sealing integrity over extended service life.
3Strength
If carbide inserts are used for the valve disc and seat, then wear resistance is improved, but the weight and cost of the valve increases
Solution Approach 1:
The patent applies the spherical-toroidal contact geometry with hardened carbide or ceramic materials specifically to the contact surfaces of the valve disc and seat, while the remainder of the valve body can be constructed from lighter, less expensive materials. This localized application of hard materials provides wear resistance exactly where needed (at the sealing contact line) without unnecessarily increasing the weight and cost of the entire valve assembly.
Data Source
AI summary
A valve includes a valve disc movable along an axial direction and has an arcing outer engagement surface with an axis of curvature transverse to the axial direction. A valve seat defines a central opening aligned with the axial direction. The valve seat has a toroidal radially inner engagement surface around the central opening configured to engage the engagement surface of the valve disc in a closed position. The engagement surface of the valve disc and the engagement surface of the valve seat are configured to form a line of contact between the outer engagement surface and the inner engagement surface. The engagement surfaces of the valve disc and of the valve seat may be a carbide or ceramic material having a hardness of 1000 HV or more.