HPLC Pump Head Design for Air Bubble Evacuation
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Solution Overview
Problem
High-performance liquid chromatography (HPLC) pumps face challenges in efficiently evacuating air bubbles from the pump chamber, especially at high pressures, leading to disturbances in chromatography pressure and flow, due to the large size of check valves and the tediousness of the priming process using syringes.
Innovation Solution
The design incorporates a pump head block and pressure sensor body with a tubular portion projecting into the sensor body, featuring diversion conduits for the inlet and outlet channels, allowing air to be effectively evacuated from the pump chamber, enabling closer placement of check valves and reducing internal volume, thus enhancing priming efficiency and reducing 'dead volume'.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pump chamber has a small internal volume to improve chromatography performance, then the check valves must be placed closer to the pump chamber, but the large size of check valves at high pressures makes this difficult to achieve
Solution Approach 1:
The patent applies nesting by placing the check valves inside the pump head block, which itself is positioned within the pump chamber assembly. The check valves are integrated into the pump head block structure, allowing them to be located close to the pump chamber while maintaining a compact overall design. This nested arrangement enables the small internal volume requirement to be met while accommodating the necessary check valve placement.
2Productivity
If the inlet and outlet channels are placed at opposite ends of the pump chamber to facilitate air evacuation, then the pump head structure becomes more complex, but this conflicts with the need to accommodate large check valves in a compact space
Solution Approach 1:
The patent resolves the spatial conflict by transitioning from a linear arrangement to a three-dimensional configuration. The inlet channel enters the pump chamber at one location while the outlet channel exits at a different spatial position, utilizing vertical and lateral dimensions rather than simply opposite ends of a linear path. This dimensional approach allows air evacuation functionality while maintaining a compact pump head structure that accommodates the check valves.
Solution Approach 2:
The pump head is segmented into distinct functional zones: the pump head block containing the check valves, the pump chamber for fluid containment, and the pressure sensor body for measurement. The inlet and outlet channels are routed through different segments, allowing air evacuation without requiring the channels to be at opposite ends of the entire assembly. This segmentation reduces overall structural complexity while maintaining evacuation efficiency.
3Ease of operation
If a syringe is used to prime the pump by drawing solvent into the pump head, then the priming process can be performed, but it is tedious and does not expedite the removal of air from the pump
Solution Approach 1:
The patent implements self-service priming by designing the pump head with integrated inlet and outlet channels that allow solvent to automatically flow through the pump chamber and evacuate air bubbles. The pressure differential created during normal pump operation drives the solvent through the chamber, eliminating the need for manual syringe operation. The system primes itself through its own operational cycles, significantly reducing priming time and operator intervention.
Data Source
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AI summary
A high or ultra high performance liquid chromatography pump (53) has a plunger rod (59) extending in an axial direction (60) into a pump chamber (55) through a plunger passage (58). The plunger rod (59) is reciprocally movable in the axial direction into the pump chamber (55) and back. An outlet channel (62,69) extends through the pump head between an outlet port (63) and the pump chamber (55) and an inlet channel (64,70) extends through the pump head between an inlet port (65) and the pump chamber (55). The pump head (54) is formed of a pump head block (56) and a pressure sensor body (57). A pressure sensor (77) is mounted to the pressure sensor body (57). A tubular portion (66) of the pump head block (56) projects into the pressure sensor body (57). The outlet channel has at least one conduit portion (69) at least partially bounded by the tubular portion of the pump head block, the conduit portion of the outlet channel extending from said pump chamber in said axial direction (60).