Application of Flow Stabilizers Paired with Micro Pumps for Eliminating Airflow Pulsation in Gas Analysis and Sampling
Background Introduction
In gas analysis and detection-related industries, gas sampling places stringent requirements on sampling pumps. The pump must deliver relatively smooth and stable airflow to ensure detection accuracy, while being compatible with complex media and capable of stable, reliable operation over extended periods. Common gas sampling pumps in the industry include micro diaphragm pumps and rotary vane pumps, each with its own advantages and disadvantages. Considering only media compatibility, lifespan, and reliability, diaphragm pumps have significant advantages. However, regarding airflow stability, diaphragm pumps – being reciprocating positive displacement pumps – exhibit greater pulsation than rotary vane pumps. To compensate for this shortcoming of reciprocating positive displacement pumps like diaphragm and piston pumps, flow stabilizers were developed.
Why does a diaphragm pump produce pulsating airflow?
Diaphragm pumps are reciprocating positive displacement pumps that transfer media by changing the pump chamber volume through diaphragm movement. The output gas flow fluctuates with the pump’s cycling frequency, creating pulsations – instantaneous airflow variations rather than a smooth output.
What is a flow stabilizer?
A flow stabilizer is a device designed to reduce the amplitude of airflow pulsations caused by reciprocating positive displacement pumps. In applications requiring relatively smooth and stable airflow, a stabilizer is integrated into the gas path to mitigate these pulsations.
How effective are flow stabilizers?
Hilin flow stabilizers combine multiple stabilization principles. Under optimal conditions, pulsation percentage can be minimized to around 2%, achieving excellent pulsation suppression.
Pulsation percentage definition:
Pulsation percentage = (Peak-to-peak instantaneous flow fluctuation after stabilizer)/(Average flow after stabilizer) × 100%
This metric reflects the stabilizer’s effectiveness.
As clearly shown in the figure below:
The blue solid line represents the instantaneous flow of a micro pump without a stabilizer, showing significant periodic pulsations.
The green solid line shows the same pump with a stabilizer, where pulsation amplitude is drastically reduced, approaching the stabilized average flow.
While providing excellent pulsation control, stabilizers also cause some flow attenuation. Hilin stabilizers feature optimized internal gas path design to maximize source flow efficiency, minimizing attenuation – optimally to around 8%.
Attenuation percentage definition:
Attenuation percentage = [(Average flow without stabilizer) – (Average flow with stabilizer)]/(Average flow without stabilizer) × 100%
This metric quantifies the flow reduction introduced by the stabilizer.
How to pair with micro pumps?
1.As a flow stabilization component that also acts as a damping element, when pairing with a micro pump, select a pump with higher flow capacity than the target requirement.
2.Refer to the stabilizer’s specifications for its effective pressure and flow ranges when matching with micro pumps to avoid affecting performance or damaging the stabilizer.
3.Stabilizers have two ports: source end and stabilized end. Their operation is unidirectional, so proper orientation is essential.
a) For vacuum (suction) pumps:
Operates in negative pressure mode
Connect source end to pump inlet (IN)
Gas flows: Stabilized end → Stabilizer → Source end → Pump
Output from stabilized end is smoothed airflow
b) For pressure (blowing) pumps:
Operates in positive pressure mode
Connect source end to pump outlet (OUT)
Gas flows: Pump → Source end → Stabilizer → Stabilized end
Output from stabilized end is smoothed airflow
4.Note: Particles in the gas stream must be <0.2mm to avoid damaging the stabilizer. A filter is strongly recommended at the stabilizer inlet.
5.For specific performance data (pulsation control and attenuation) of Hilin micro pumps with stabilizers, consult the stabilizer manual or contact our technical team.