Sealed Magnet Check Valve for Precise Solvent Flow Control
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Solution Overview
Problem
Traditional ball-and-seat check valves in liquid chromatography systems often fail due to contamination, getting stuck open or closed, which affects the precision of solvent flow and chromatographic measurement data, and conventional active check valves using electro-magnetic actuation can introduce artifacts with dynamic seals.
Innovation Solution
An active check valve with a solenoid coil and a plunger assembly that includes a permanent magnet, where the plunger assembly is separate from the ball, allowing for electro-magnetic actuation to open and close the valve without direct contact, using static seals and a sealed internal volume to prevent solvent contact with internal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ball-and-seat check valves are used, then the structure is simple and cost-effective, but the valve gets stuck open or closed due to contamination from solvents
Solution Approach 1:
The patent replaces the traditional mechanical ball-and-seat check valve system with an active check valve system that uses electromagnetic actuation. The solenoid coil generates a magnetic field to move a plunger assembly, which controls the opening and closing of the valve through a sealing member, eliminating the need for a floating ball that is susceptible to contamination adhesion.
Solution Approach 2:
The patent introduces a plunger assembly with a magnet as an intermediary between the electromagnetic field and the sealing member. This plunger assembly is sealed to prevent solvent contact with the magnet, while still transmitting the electromagnetic actuation force to control the valve opening and closing, thus protecting the magnetic component from contamination.
2Reliability
If active check valves with dynamic seals are used, then the valve can be actuated to overcome adhesion, but dynamic seals introduce artifacts to solvent flow
Solution Approach 1:
The patent extracts the dynamic sealing components from the actuation mechanism. The plunger assembly is completely sealed to prevent solvent contact, and the actuation force is transmitted through this sealed barrier rather than through dynamic seals that would contact the solvent flow path, thereby eliminating seal artifacts.
Solution Approach 2:
The patent employs a sealed plunger assembly housing that acts as a barrier between the electromagnetic actuator components and the solvent. This sealed enclosure prevents solvent from reaching internal components while allowing the plunger to move and transmit actuation force, eliminating the need for dynamic seals in the solvent path.
3Ease of operation
If the plunger assembly contacts the solvent, then actuation can be achieved, but internal components become contaminated
Solution Approach 1:
The patent creates an asymmetric arrangement where the plunger assembly is positioned off-center in the valve body, allowing it to move between open and closed positions while maintaining a sealed enclosure. This asymmetric positioning enables actuation functionality while the sealed housing prevents solvent contact with the magnet and other internal components.
4Reliability
If the ball is held against the seat by weak attraction, then the valve closes, but contamination causes the valve to get stuck closed
Solution Approach 1:
The patent replaces the passive ball-and-seat closing mechanism with an active sealed sealing member that is actuated by the plunger assembly. The sealing member is pushed against the valve seat by the plunger to ensure reliable closing, eliminating reliance on weak gravitational or elastic forces that can be overcome by contamination adhesion.
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 ensures precise and reproducible solvent flow by avoiding disruptions and artifacts, maintaining high volumetric precision and accuracy in solvent composition, and is applicable beyond liquid chromatography applications.
Implementation Method 1
The coil is attached to the valve body and configured to generate a magnetic field in response to an electrical current
Implementation Method 2
The plunger assembly is at least partially disposed within the coil and movable along the flow path between a closed position and an open position. The magnet is disposed in the sealed internal volume
Data Source
AI summary
Described is an active check valve that uses electro-magnetic actuation for operation. The valve includes a plunger assembly having a magnet in a sealed internal volume. The plunger assembly further includes a plunger tip that extends from either a plunger assembly housing or a sealing member. Although the plunger assembly is disposed in the solvent flow, the magnet is not exposed to the solvent. When the valve is actuated, the plunger tip moves the sealing member to open or close the valve. Optionally, an arming force may be applied to the sealing member in advance of opening or closing to reduce the subsequent additional force necessary to move the sealing member during opening or closing, thereby improving the accuracy of the solvent composition in liquid chromatography system applications.