Differential Pressure Transducer Damping for Pump Ripple
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Solution Overview
Problem
Differential pressure transducers are susceptible to pump ripple, a sinusoidally varying pressure fluctuation that can cause resonance and excessive stress leading to brittle failure, especially in compact designs where resonance amplification exceeds the sensor's rating, and can also allow contaminants to pass through, damaging the sensor and downstream equipment.
Innovation Solution
A differential pressure transducer with a coiled tube or adjustable dampening chamber, such as a spiral inlet tube and volume cavity, is used to suppress or attenuate unwanted pressure fluctuations, minimizing stress on the sensor and preventing resonance, while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact pressure transducer design is used, then the device size is reduced, but the transducer becomes susceptible to pump ripple resonance and excessive stress leading to brittle failure
Solution Approach 1:
A compliance chamber is introduced as an intermediary component between the pressure transducer and the pump system. This chamber acts as a buffer that absorbs pressure fluctuations and prevents pump ripple from directly affecting the transducer, thereby protecting the compact design from resonance and excessive stress while maintaining small size.
Solution Approach 2:
The compliance chamber provides beforehand cushioning by pre-absorbing pressure fluctuations before they reach the transducer. This protective measure is built into the system design, cushioning the transducer against pump ripple-induced stress and resonance before damage can occur.
2Measurement precision
If the transducer is ported directly to pump pressure, then accurate pressure measurement is achieved, but pump ripple causes resonance and amplification that can exceed sensor ratings
Solution Approach 1:
The compliance chamber serves as a mediator between the pump pressure source and the transducer. It allows the transducer to remain connected to the pressure system for accurate measurement while filtering out harmful pump ripple frequencies, preventing resonance without compromising measurement precision.
Solution Approach 2:
The compliance chamber is strategically positioned at a specific location in the pressure system where it can locally address the pump ripple issue. By placing the compliance element near the transducer, the solution provides localized damping exactly where needed, maintaining measurement accuracy while eliminating harmful vibrations.
3Reliability
If pump pressure is monitored in systems with pumps, then operational parameters are tracked, but the transducer is exposed to sinusoidally varying pressure fluctuations that can cause failure
Solution Approach 1:
The compliance chamber provides beforehand cushioning specifically针对 the sinusoidally varying pressure fluctuations from pump operation. This protective measure is built into the system design, cushioning the transducer against pump-induced stress before damage can occur, enabling reliable operational monitoring.
Solution Approach 2:
The compliance chamber converts the harmful effect of pump-induced pressure fluctuations into a beneficial damping effect. By allowing controlled compression and expansion of the compliance element, the system transforms the harmful sinusoidal variations into a protective mechanism that reduces peak stresses and prevents transducer failure.
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 effectively reduces the impact of pump ripple, preventing sensor damage and ensuring accurate pressure measurements by suppressing harmful pressure waves, thus enhancing the reliability and longevity of the transducer.
Implementation Method 1
a coiled tube in series with one of said ports and dimensioned to suppress said varying pressure fluctuation
Implementation Method 2
said diaphragm having pressure sensing elements on said diaphragm which elements provide an output proportional to an applied pressure on said diaphragm
Data Source
AI summary
A single pressure sensing capsule has a reference pressure ported to the rear side of a silicon sensing die. The front side of the silicon sensing die receives a main pressure at another port. The difference between the main and reference pressure results in the sensor providing an differential pressure output. The reference pressure or main pressure may be derived from a pump pressure which is being monitored. The pump pressure output is subjected to a pump ripple or a sinusoidally varying pressure. In order to compensate for pump ripple, a coiled tube or an adjustable dampening chamber comprising a spiral inlet tube and a volume cavity can be used. The tube length is selected to suppress the pump ripple as applied to the sensor die. In this manner, the pump ripple cannot cause resonance which would result in pressure amplification and which pressure amplification would destroy the sensor.