Flexible Bag Systems

Flexible bag systems have numerous applications in Bioprocessing for which Colder quick connections have been used since the beginning of single-use connections. These include sampling, media/buffer storage, and short or long term product hold. Specialized bags have even been developed to store frozen protein at -40ºC.

Flexible bag systems are used to hold sterile fluid from 30 ml to 3000 L. Bags up to 200 L are typically made in a two-sided “pillow” design, whereas larger bags (50 to 3000 L) utilize a gusseted construction to achieve a 3-dimensional shape during filling. Bags can be filled through Colder's MPC or MPX couplings and capped (with MPC and MPX caps) at the completion of filling or through Colder's HFC39 couplings with integrated shutoff valves.

A number of manufacturer-specific plastic film systems are used for flexible bags. Common features among film systems are an inert fluid contact layer of polyethylene or ethylene vinyl acetate; a gas barrier layer, typically ethyl vinyl alcohol; and an exterior layer designed to increase bag strength. Bags are constructed in single, double or triple web formats. In double and triple web formats, film layers are separate, but sealed together at the bag seams. With the single web format, films layers are laminated together use heat and/or adhesive.

Assembled bag systems are sterilized by gamma irradiation. Bag systems designers and users employ special components and techniques to maintain sterility within the system. These include attaching sterilizing filters during bag assemble; making connection with standard couplers such as  Colder Product’s MPC and MPX couplers in a Class 100 “mini-cleanroom” environment; sterile tubing welders and aseptic or sterile connectors including Colder's Steam-Thru Connections.