Single-Use Technologies: Steam-Thru
Patented Steam-Thru® Connection
technology creates a sterile link between pre-sterilized bag systems or tube sets and stainless process equipment. The product’s innovative three-port design maximizes sterility assurance by eliminating “dead legs” and allowing steam to pass directly through the connection to “steam on” to stainless equipment.
Sterility assurance is further expanded with the introduction of Steam-Thru II, which offers “steam on” and “steam off” capability, allowing both a sterile connection and sterile disconnection without the need for a laminar flow hood. This reduces the potential of microbial contamination of the process flow path, as well as environmental contamination within facilities.
The Steam-Thru product line includes several valve and termination options that provide the flexibility needed to meet today’s mounting and flow requirements. The connection is attached to single-use bag systems or tubing, then pre-sterilized by gamma irradiation up to 50 KiloGrays or autoclaved up to 129°C for 60 minutes, depending on the product configuration.
For mounting to the processing equipment, engineers may specify the connection with either a ¾” or 1 ½” sanitary termination on the middle port. Tri-clover clamps are used to secure the middle sanitary to the equipment and the lower sanitary to the steam trap. Once attached, these two lower ports allow a true steam through SIP process to eliminate potential “dead legs” that trap contaminants. With Steam-Thru® II, an SIP cycle of up to 135°C or 35 PSI can be performed for up to 60 minutes to “steam on” the connector to the equipment. Effectiveness of the “steam on” cycle was confirmed through bacterial challenge testing using Bacillus stearotheromphilus performed at the University of Minnesota’s Biotechnology Research Center.
Once the SIP cycle is complete, the operator depresses the thumb latch to allow valve transition from the steam position to the flow position. This creates a sterile flow path between the stainless equipment and the single-use system, allowing aseptic fluid transfer to occur. A benefit of the Steam-Thru II valve design is a maximum Cv value of 8.2, which translates to a flow rate of 43.9 liters per minute at 2 PSI, making it appropriate for high volume applications.
After fluid transfer is complete, depressing the thumb latch again allows repositioning of the valve back to the steam position for a second SIP or “steam off” cycle. This eliminates any biologic residual remaining between the process equipment and the single-use system, minimizing the potential of environmental contamination at disconnection.
In addition to the bacterial challenge testing completed on the “steam on” cycle, bacterial challenge tests were performed following media transfer on the “steam off” cycle. Bacterial ingress tests using Brevendimonas diminuta were conducted by Northview Labs to verify post sterilization seal performance. Other performance tests, including helium/steam leak, tensile, and maximum burst, were completed to assure design and process integrity. The Steam-Thru II is comprised of non-animal origin USP Class VI polysulfone and platinum-cured silicone seals, which were tested for biocompatibility.