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Humidification and a controlled gas composition for carrying out cell cultivations

Do you have a shaking incubator with a small capacity that is restricted to temperature control? Would you like to implement humidification and a controlled gas composition for carrying out cell cultivations?

The combination of FlowCon and AerationSystem from Kuhner enables the user to run shake flasks cultivations in non-humidified and non-CO2-controlled incubator shakers. The FlowCon provides a precise gas composition and flow rate.  Simultaneously, the AerationSystem (consisting of GasDivider and AerationCaps) humidifies and distributes the gas flow evenly to the connected shake flasks, preventing high evaporation losses and stabilizes the pH of the media. By controlling the chemical composition of the inlet air with the FlowCon, it is not only possible to supplement CO2 but also to reduce the concentration of oxygen (O2) or even implement hypoxic conditions using nitrogen (N2)*. This control of gas compositions allows for a variety of different applications, including stem cell processes that require physiological oxygen concentration at 5% O2 or anaerobic cultivations in a nitrogen atmosphere.

Humidity control


CO2 control







The Kuhner FlowCon is a stand-alone gas mixing device, which has been developed for the R&D environment and the initial production steps in bioreactors with disposable bags. It provides the perfect headspace composition for your cultures by mixing up to four gases (including both pure and mixed gases). Whether stabilizing the pH in cell cultivations with CO2, or reducing oxygen concentration for microaerophilic organisms, the FlowCon gas mixer meets all of the user’s needs. The FlowCon can be used as a stand-alone device and is also fully compatible with other Kuhner equipment (including shaking incubators, disposable bioreactors, etc.).

Order number Description
106982 FlowCon - Mixing up to four gases (FlowCon 2/3/4), Selectable flow rate: 0-1 [sL/min], 0-20 [sL/min]


For universities and start-ups, which have a tight budget but want to perform cell culture (also stem cell) processes which demand a controlled gas composition, the Kuhner Flowmeter provides an optimal solution. The Flowmeter is integrated in the gas line between the gas cylinder (with precise pressure reducer), containing the required gas composition for the cell culture process, and the Kuhner AerationSystem. Thereby, the combination of Flowmeter, gas cylinder, and pressure reducer provides a cost-efficient alternative to a gas mixing device with mass flow controllers. Less effort is required in terms of connection and control of the gas supply. Also, there is a reduced risk potential by using a premixed gas supply compared to a gas mixing device as no pure oxygen or carbon dioxide must be handled. Also, tools and equipment like pressure reducers for connecting and using gas cylinders are already present in most laboratories.

The Flowmeter operates in accordance with the float measuring principle. The measuring unit consists of a small glass cone in which a float can move freely up and down. The small Flowmeter (150x275x125 mm) can simply be placed on top of the incubator shaker or besides the lab shaker.

The Flowmeter operates in accordance with the float measuring principle. The measuring unit consists of a small glass cone in which a float can move freely up and down. The small Flowmeter (150x275x125 mm) can simply be placed on top of the incubator shaker or besides the lab shaker.

The Kuhner AerationSystem consists of the Kuhner GasDivider and special shake flask caps. The patented GasDivider is placed on the shaking tray of the shaker (in a temperature-controlled room) or incubator shaker with temperature control. It humidifies and distributes the gas flow evenly to the connected shake flasks. The shake flasks can be connected via AerationCaps (e.g., for single-use flasks like Corning flasks) or FlexCaps (e.g., for glass Erlenmeyer flasks and flasks with baffles). Evaporation losses from the shake flasks are significantly reduced, which is particularly advantageous for very long cultivation times (such as cell culture processes) and contributes to successful cultivations. As the GasDivider is placed on the shaking tray, the gas flow is perfectly adapted to the cultivation temperature. Furthermore, opening the incubator door does not affect the gas composition of the connected shake flasks.

Order number Description
108413 Flowmeter - Gas flowmeter with holder and stand



The Kuhner FlowCon provides a single mixed and dry gas flow, which usually requires humidification and even distribution across several shake flasks. This task is performed by the Kuhner GasDivider which humidifies the gas flow and provides a precise gas distribution independent of the flask type attached, the tube length or any filters in-between. As the GasDivider is placed on the shaking tray inside the incubator, the gas flow is also perfectly adapted to the incubator temperature.

Order number Description
105519 GasDivider - The GasDivider humidifies and evenly distributes a mixed and dry gas flow among shake flasks, adapting to various flask types and incubator temperatures.

Shake flask caps: AerationCaps and FlexCaps

Nowadays, numerous shake flask variants are used in laboratories. To counter this diversity, Kuhner offers two different closure caps for the AerationSystem: AerationCaps and FlexCaps.

The Kuhner AerationCaps are used for aeration of standard single-use shake flasks (e.g., corning). They can be quickly and easily attached to the sterile caps ("Vent Caps"). Each AerationCap has two identical nozzles that are used for supply and exhaust air. The AerationCaps (as well as the FlexCaps) are connected to the GasDivider via gas-tight tubes. The AerationCaps are reusable, but not autoclavable. Since they are placed on the sterile covers of the single-use shake flasks, they do not come into contact with culture liquid and therefore do not need to be sterilized.


The Kuhner FlexCap is a universal silicone adapter lid that enables the utilization of various sizes and forms of shake flasks with the Kuhner AerationSystem. Its specific construction seals both the smaller and more narrow flasks (min. 25 mm inner neck diameter) and the larger and wider flasks (max. 55 mm outer neck diameter), respectively, using the same universal lid. With the FlexCap, also cultivations in custom-made flasks and baffled shake flasks are accessible for aeration and humidification with the AerationSystem. Besides the ports for supply and exhaust air, the FlexCap comes with an extra port for external feeding and sampling. Best of all, the FlexCap is reusable by autoclaving at temperatures up to 121°C without losing its mechanical performance.

Order number Description
105497 Kuhner AerationCap for 125 mL Corning flask
105498 Kuhner AerationCap for 250 mL Corning flask
105499 Kuhner AerationCap for 500 mL Corning flask
107105 FlexCap - Flexible silicone flask plug. Kuhner FlexCap 107105 Flexible silicone flask plug. To connect individual shake flasks with Kuhner TOM. The Flexcap allows to connect shake flask with a neck diameter between 25 (ID) - 55 (OD) mm with the Kuhner TOM. Autoclavable at 121°C. 4 pcs.


Mammalian Cell Cultivation using AerationCaps for Shake Flask Gas Supply

In our Science Room, we offer general information and data of cultivation processes in shaken bioreactors.

Kuhner shakers are suitable for the cultivation of microbial, plant, human and animal cell cultures. Find more information about the different application areas and suitable product recommendations for optimal cultivation here.

Stem cells
Cell culture
Plant cells & algae


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