Gas control and back pressure control in the biotechnology industry

There are two specific areas where we support the Biotechnology Industry. The first is with gas control to reactors and fermenters, the second is with single use and multi-use back pressure controllers

Gas Measurement and Control

Bioreactors and fermenters require a precise and wide-ranging supply of feed gases (usually N2, O2, CO2 and Air) and the Alicat Bio-Series are specifically designed for this application. Feedback from customers has highlighted that the following features are of particular benefit for this industry.

High controllable range (otherwise known as turndown) – 10,000:1

Allows for the consolidation of flow lines – often replacing 3 lines with 1.  Clearly this saves cost on the MFC’s themselves, but also within the procurement and fitting of ancillary equipment and the flow lines themselves. Reduced componentry means a reduced risk of contamination. Please see the associated White Paper on Alicat Mass Flow Controllers’ Resistance to Backpressure Contamination.

ASME BPE compliant materials

Although different engineers’ approach this in many different ways, there is general agreement that 316 stainless steel and USP Class VI elastomers are a good starting point. Naturally the Bio-Series conform to this. That said, some engineers prefer to stipulate their own specifications and we are only too happy to follow this lead and work together to manufacture the ideal solution within their specification/cost balance. Please see the associated White Paper on Elastomer Considerations for Bioreactors.

Tolerance to water ingression

Unfortunately, in the real world there are too many chances where the flow controller can get inadvertently exposed to water. Alicat instruments are highly robust and continue to perform well in this scenario – significantly better than traditional designs of MFC. Please see the associated White Paper.

Display – easy understanding of status, flow control

Whilst every system is governed by a data controller it is our experience that the operator gains significant peace of mind by having the ability to know exactly what a specific mass flow controller is doing simply at a glance.

 

Gas Select – flexible spares

Having the ability to switch a unit to the other gases (N2, O2, CO2, Air) and in unison with the high controllable range means that a user can easily swap in anything at the same or similar flow rate. There is a huge benefit in reduced spares and far greater flexibility. 

Valve Drive – know the status of the valve

Valve Drive is standard on Bio-Series and optional on other Alicat Series. It displays and signals the percentage of total available voltage that the valve is using to open – typically, this value will go up when the drive has to work harder/apply more voltage to hold the same setpoint.  Typically, this is indicative of contaminants in the line, or perhaps a decrease in line pressure, and allows the user to keep an eye on any change over time and/or whether an event is significant. The feed-back from users is that in the real world they tend to use this benefit as a kind of proxy for valve health.

 

Back Pressure Control

Permanent Installation – Multi-Use

The Equilibar FD Series has been specifically for biotechnology and pharmaceutical and whilst its’ principle of operation is similar to other Equilibar Back Pressure Regulators, the FD series meets the ASME BPE requirements. Some of these requirements are listed below:

  • USP class 6
  • EU 1935/2004 (on request)
  • Crevice free design
  • Electropolished
  • Surface roughness Ra < 0.5 µm

The FD series has been developed to achieve optimal draining.  The device is suitable for both Clean-In-Place (CIP) and Steam-In-Place (SIP) regimes and can be flushed in both directions. Whilst the standard operating mode could be for ultra-low pressure- and flow control (perhaps with a Cv of 10E-7) the CIP flows are often considerably higher. These contradictory requirements can be fulfilled by the FD Series often simplifying installation requirements, reducing cost, eliminating the need for bypass lines, pressure relief valves etc while maintaining the very best accuracy and control.

The Equilibar FD series is available with a CV range of 10E-7 to 19 over only 5 model types, ½” to 2”, and has a maximum pressure of 10 bar gauge (150 PSI). It is equipped with two diaphragms. The top diaphragm is the actuation diaphragm. The bottom diaphragm reduces the effect of water hammering, that sometimes occurs at a specific combination of flow and pressure. The diaphragms are available in different materials such as PTFE, Buna-N, FKM and EPDM (UPS class VI). The standard diaphragms allow a maximum temperature of 150°C. Higher temperatures can be achieved by applying different polymeric- or alloy diaphragms. Body materials are available in Stainless Steel, Hastelloy, Titanium, Monel, Zirconium, PTFE and PVDF with yet more options available on request. 

Common applications include chromatography pressure control, high precision pressure control within biopharmaceutical filtration and pump pressure regime control for accurate product blending.

Single Use Installation

The SD series acknowledges the rapidly expanding requirements of Biopharmaceutical Industry for single use, lower cost components, that can be sterilized through irradiation and disposed of after use. The Equilibar SD Series offers USP Class VI polymers that can be sterilized as a complete assembly with the wetted components and diaphragm being disposable whilst the permanent support housing can be retained. By use of sanitary clamp connections for quick and easy assembly these regulators combine ease of use with excellent stability, smooth control and seamless automation. Options include a sterilized version (Gamma radiation) and Sanitary Certifications.

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