Positive Displacement Pump Leakage Detection via Pressure Analysis
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Solution Overview
Problem
Screw spindle pumps experience internal and outer leakages due to wear, leading to reduced volumetric efficiency, which is difficult to measure accurately without expensive flow meters, necessitating a simpler and more reliable method to assess wear conditions.
Innovation Solution
A method involving pressure measurements at different rotary speeds to indirectly determine leakage flow and actual volume flow rate by analyzing the pressure curve, which correlates with leakage points and flow resistance, allowing for assessment of internal and outer leakages without direct volume flow rate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive volume flow meters are used to measure actual volume flow rate, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses pressure as an intermediary parameter to indirectly determine volume flow rate and leakage. Instead of directly measuring volume flow rate with complex flow meters, the system measures pressure (a simpler parameter) and uses the known relationship between pressure, speed, and flow rate in positive displacement pumps to calculate the actual volume flow rate and detect leakage.
Solution Approach 2:
The patent replaces the mechanical volume flow measurement system (flow meters) with a pressure measurement system combined with computational analysis. By measuring pressure at different speeds and analyzing the pressure-speed curve, the system substitutes direct mechanical flow measurement with a more simplified pressure-based indirect measurement approach.
2Measurement precision
If direct volume flow rate measurement is performed, then measurement precision is improved, but ease of operation deteriorates due to cumbersome measurement procedures
Solution Approach 1:
The patent uses pressure as an intermediary parameter that is easier to measure and more accessible than direct volume flow rate. Pressure sensors can be conveniently placed in the pressure line, and the pressure readings at different speeds provide sufficient information to detect leakage without requiring complex flow measurement procedures.
Solution Approach 2:
The patent changes the measurement parameter from volume flow rate to pressure. By measuring pressure at different rotational speeds and analyzing how pressure changes with speed, the system achieves accurate leakage detection through a simpler parameter that is easier to measure and more readily available during pump operation.
3Productivity
If pump operates at higher speeds to increase productivity, then productivity is improved, but loss of energy increases due to greater leakage
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the pressure-speed relationship to detect changes in leakage. By measuring pressure at different speeds and comparing the actual performance against expected performance, the system provides feedback on pump condition and leakage levels, enabling operators to optimize operating speeds to balance productivity with energy efficiency.
Solution Approach 2:
The patent performs preliminary assessment of pump condition by measuring pressure at different speeds before full operation. By characterizing the pressure-speed relationship and detecting leakage trends in advance, the system enables proactive maintenance and optimization of operating parameters to prevent excessive energy loss from leakage before it significantly impacts efficiency.
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 reliable determination of pump wear conditions and volumetric efficiency by measuring pressure drops at varying speeds, providing insights into leakage causes and allowing for timely maintenance, thus maintaining pump performance without the need for expensive flow meters.
Implementation Method 1
measuring the pressure in the pressure line, successively driving the pump at different rotary speeds of the displacement body, measuring the pressure in the pressure line for each rotary speed of the displacement body
Implementation Method 2
In positive displacement pumps, ideally, the volume flow rate is uniquely determined by the geometry of the displacement bodies and the speed thereof
Implementation Method 3
all leakage points of the pump, together, present a certain obstruction for the medium flowing out, and this obstruction determines the relation between the pressure drop and the leakage volume flow rate
Data Source
Figure 1~2
AI summary
A method of detecting leakage in a pump (10) that has at least one displacement body (12) for displacing a medium to be pumped into a pressure line (20), characterized by the steps of: - closing-off the pressure line (20), - operating the pump (10) with a known speed of the displacement body (12), and - measuring the pressure (P) in the pressure line (20).