Displacement Pump Leak Rate Detection Using Pressure Repressurization
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Solution Overview
Problem
Existing laboratory automation apparatuses face challenges in detecting liquid leak rates in displacement pumps without requiring removal from the system, which can affect the accuracy and reliability of liquid handling operations.
Innovation Solution
An integrated method and computer program that utilize a pressure sensor and displacement pump to monitor pressure changes over time, calculating leak rate by pressurizing and repressurizing the system to detect leakage within the pump and associated components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the displacement pump is removed from the laboratory automation apparatus for leak rate measurement, then the leak rate can be measured accurately, but the system complexity increases and productivity decreases due to disassembly requirements
Solution Approach 1:
The system performs preliminary actions by closing the valve before measurement to isolate the pump, and uses pre-programmed pressure sequences to prepare the system for accurate leak rate detection without disassembly. The control unit executes predetermined pressure sequences that isolate the pump and enable accurate measurement while the pump remains installed.
Solution Approach 2:
The control unit acts as an intermediary by managing the pressure sequences and valve operations to enable leak rate measurement without physical removal of the pump. The control unit coordinates the pressure sensor readings and valve positioning to calculate leak rate while the pump remains integrated in the system.
2Productivity
If the displacement pump remains integrated in the laboratory automation apparatus, then productivity is maintained, but the leak rate detection becomes more difficult without removal
Solution Approach 1:
The measurement process is segmented into distinct phases: pressurization phase, holding phase for leak detection, and depressurization phase. The control unit manages each phase separately, isolating the pump from the rest of the system during measurement while maintaining integration during normal operation. This segmentation enables accurate leak detection without physical disassembly.
Solution Approach 2:
The system employs periodic action through repeated pressure sequences that cycle between pressurization, holding, and depressurization phases. The control unit executes these periodic pressure sequences to consistently measure leak rate while the pump remains integrated, making detection reliable without requiring pump removal.
3Measurement precision
If pressure monitoring is performed over a long time period to detect small leaks, then measurement precision improves, but the time required for measurement increases
Solution Approach 1:
The system changes pressure parameters by establishing a predetermined pressure sequence that sets a target pressure level. The control unit monitors pressure deviations from this established pressure level over time, enabling detection of small leaks through controlled pressure changes rather than static long-term monitoring. This parameter change approach maintains precision while reducing measurement time.
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
Enables in-situ leak rate detection of displacement pumps, ensuring reliable liquid supply without disassembly, and providing a routine control mechanism for maintaining pump performance.
Implementation Method 1
monitoring the pressure in the system by the pressure sensor during a predetermined time period Δt
Implementation Method 2
pressurizing a liquid in the system to an initial pressure P1 using the displacement pump
Data Source
AI summary
A method for detecting a leak rate of a displacement pump integrated in a laboratory automation apparatus having a valve, a displacement pump and a pressure sensor. The method involves closing the valve, pressurizing the system with a liquid to an initial pressure P1 using the displacement pump, monitoring the pressure by the pressure sensor during time period Dt starting from initial pressure P1 at time, detecting a second pressure P2 at t2 at the end of the time period Dt, wherein pressure P2 is below pressure P1 when leakage occurs, repressurizing the system to pressure P1 by displacing an additional volume DV of the liquid using the displacement pump, and calculating the leak rate by dividing the additional volume DV by the predetermined time period Dt.