Dual-Path Control Fitting for Sand-Resistant Flow Switching
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Solution Overview
Problem
Conventional shut-off valves used in high-pressure fluid transportation systems, such as those for fracturing oil and gas wells, face issues with seizing, require frequent maintenance, and are prone to sand buildup, which interferes with operation, especially when dealing with abrasive and corrosive frac slurries.
Innovation Solution
The development of dual path control fittings with a cylindrical plunger and radial conduits that allow for selective fluid flow and tool access, featuring robust sealing elements and a compact design to minimize grease usage and sand accumulation, eliminating the need for separate shut-off valves and reducing maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shut-off valves are used in high-pressure fluid transportation systems, then fluid flow control is achieved, but the valves are prone to seizing and sand buildup which interferes with operation
Solution Approach 1:
The invention removes the traditional valve closure element (gate, ball, or plug) from the system. Instead of using a moving valve component to shut off flow, the patent employs a spool assembly with radial bore alignment that can be rotated to selectively connect different flow paths. This extraction of the traditional valve mechanism eliminates the seizing and sand buildup problems associated with conventional shut-off valves while maintaining flow control capability.
Solution Approach 2:
Instead of using a valve closure element to block flow, the invention inverts the approach by using an open spool assembly where flow is controlled by aligning or misaligning radial bores through rotation. The default state is open flow, and control is achieved by rotating the spool to disconnect flow paths rather than blocking them with a closure element. This inversion eliminates the mechanical interference problems of traditional valves.
2Reliability
If conventional shut-off valves are used, then fluid flow can be controlled, but frequent maintenance is required due to seizing and sand buildup
Solution Approach 1:
By removing the traditional valve closure element that is prone to seizing and sand accumulation, the invention eliminates the primary maintenance issues. The spool assembly with radial bores has no closure surfaces that can seize or accumulate sand, significantly reducing maintenance frequency and improving ease of repair while maintaining reliable flow control.
Solution Approach 2:
The spool assembly design allows for easy rotation between positions and can be manually operated without complex actuation mechanisms. The simple rotational movement between discrete positions enables operators to easily switch flow paths and perform maintenance operations without specialized tools or procedures, embodying the self-service principle.
3Reliability
If conventional shut-off valves are used, then grease must be applied to prevent seizing, but grease usage leads to sand accumulation and operational interference
Solution Approach 1:
The invention removes the need for grease entirely by eliminating traditional valve closure elements that require lubrication to prevent seizing. The spool assembly operates through rotational alignment of radial bores without sliding or rotating closure surfaces that would generate heat or require lubrication, thereby eliminating the source of sand accumulation from grease while maintaining reliable operation.
Solution Approach 2:
The invention replaces the mechanical sliding and rotating closure mechanism of conventional valves with a rotational alignment mechanism. Instead of a closure element moving against a seat, the spool assembly uses aligned radial bores to control flow paths. This mechanical substitution eliminates the need for lubrication and prevents sand buildup while maintaining flow control reliability.
Data Source
AI summary
Dual path control fittings have a fitting body and a cylindrical plunger. The fitting body has a cylindrical bore, a first conduit, and a second conduit. The cylindrical bore provides a first inlet and an opening. The first conduit provides a second inlet. The second conduit provides an outlet. The cylindrical plunger is mounted for reciprocation in the bore and has a first conduit and a second conduit. The first conduit extends from one end of the plunger to a port on the circumference of the plunger. The second conduit extends transversely across the plunger. The plunger has a first position in which the port is aligned with the second fitting body conduit to provide a first path and a second position in which the plunger second conduit is aligned with the fitting body first and second conduits to provide a second path.