Why is reliability an important mass flow controller parameter for Bioreactors?

November 24, 2020 Dion Oudejans & Vincent Hengeveld

In bioreactors delicate processes take place to multiply biological materials. These processes contain valuable substances, sometimes even beyond a price tag, as these can be an important step in a new vaccine or treatment.

Our commitment to our customers in the biotech industry is to make bioreactors work with reliable and reproducible mass flow controllers. 
For this blog we interviewed Dion Oudejans and Vincent Hengeveld, Product Managers at Bronkhorst about reliable flow controllers. 

Reliability refers to the quality of being able to be trusted to do what somebody wants or needs (Definition Oxford dictionary). Vincent and Dion explain that our commitment to reliability is built on various pillars.

mass flow controller parameter for bioreactor

By providing the most reliable mass flow instruments - using robust sensors and valves with stable electronics and firmware¸ documented in material certificates - high accuracy which is documented in calibration certificates and best in class mean-time-between-failure (MTBF) data based on the IEC 61508 standard, the quality can be quaranteed. 

Could you explain what the high accuracy statement means and why this is an important selection criteria for our customers in the biotech industry?

Bronkhorst MTBF Statement

Why is an accurate gas flow control needed?

Optimal accuracy and ratios are required to allow the biological substance to grow in the right environmental conditions. During a bioreactor campaign, biological substance grows over time and requires an increasing flow rate during the growth process. Both low and high gas flow rates are needed.  

How is the gas flow controlled?

For these applications Bronkhorst offers mass flow controllers, based on reliable and accurate capillary bypass technology and valve technology, which can achieve a dynamic flow range of up to 1 : 200, providing the low and high flow rates required for the growth process. 

Mass flow controllers which are built with capillary bypass technology have a tube-shaped flow sensor inside that is positioned parallel – in bypass – with the main flow path. There is an accurate split of gas flow into the flow sensor and the main flow path, see picture [flow sensor used in the capillary bypass technology]. This particular technology enables reliable and accurate flow measurement and control for all different gases involved. 

Video explaining the principle of bypass technology

Flow sensor used in the capillary bypass technology
Flow sensor used in the capillary bypass technology

Only a part of the gas stream flows through the sensor and is warmed up by two heater elements (RHT1 and RHT2). The gas flow through the flow sensor is a proportional measure for the total flow through the instrument. Due to the homogeneous nature of the temperature distribution within the sensor, only the flow rate, the density and the heat capacity of the gas determine the flow output signal (Q, ρ, Cp). 

Conversion factors (ρ۰Cp) can be applied to calculate the flow rate of gases other than the calibration gas.

Reliability over time – MTBF rating

Mean Time Between Failures (MTBF) is used as a measure for availability and reliability of products. MTBF predicts the time that equipment is operating between breakdowns or stoppages. There are several methods of calculating the MTBF rating, with the IEC 61508 based on the Exida component database being the industry standard. With an MTBF rating of over 130 years for the major biotech industry product lines, we are best-in-class.

Easy field calibration

Easy field calibration with Air/N2, thanks to accurate conversion method and free software tools, supports our customer base to maintain the high accuracy documented in the calibration certificate provided at arrival of the mass flow controller.  

Check our bioreactor market page for more information about flow meters and controlles for bioreactor and ferementation.

bioreactor in use in fermenter and fermentation
Bioreactor in fermenter

Intelligent flow controllers for bioreactor processes

Especially for the valuable processes as these, it is very helpful if you can monitor the ‘health’ of your instruments, to ensure the continuity of the process. For this several parameters & diagnostics are interesting:

Bypass gas flow meter
Bypass gass flow meter

  • Measuring the device internal temperature and detecting temperature variations to improve product quality
  • Response alarm to monitor if the flow controller reaches and maintains its setpoint within the specified limits. It it helpful to indicate if the inlet pressure is too low, if a gas bottle is almost depleted, or to detect obstructions in the system. 
  • Power-up alarm message and function to return; after a power failure the process can continue directly returning to the last setpoint. 
  • Measure & valve out; by comparing the values of these parameters over time, you can detect if something has changed in the setup. E.g. a variation in inlet pressure of if there is some clogging or wear of components in the setup. In this case maintenance is adviced. 

Mass flow controllers for Biotechnology

Reliable gas flow control in bioreactor processes is crucial to allow the biological substance to grow in the perfect environmental conditions. Using automated instruments, such as flow controllers, with intelligent parameters can help you ensure the continuity of the process. 
Bronkhorst digital mass flow controllers offer a range of parameters for extended measurement, control and diagnostics functionality, such as: 

  • temperature measurement
  • response alarm
  • power-up alarm
  • valve out 
  • and more

Would you like more information about bioreactor flow controllers?

Check our recommended products Contact our bioreactor specialists

Bronkhorst USA LLC

57 South Commerce Way
Suite 120
USA - Bethlehem, PA 18017 
Tel.  +1-610-866-6750

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