Biomedical Engineering Reference
In-Depth Information
pressure switch inside the pump can automatically stop the pump when the
pressure reaches a specified level.
The disposable diaphragm pump head must be integrated into the transfer
line prior to sterilization. As the pump head is totally closed, no other part
of the pump comes into contact with the fluid. After the process, the pump
head is disposed of, together with the rest of the transfer line. Flow rates of
0.1-4,000 L/h can be achieved with disposable diaphragm pumps such as
from Quattroflow (
www.quattrowlow.com
)
.
Aseptic Coupling
One of the most commonly used method is to connect the tubes or compo-
nents using sterile connectors under a laminar flow hood; however, this is
not always possible specially when the components such as disposable bags
are large and cannot be moved.
Some connectors require installation in a laminar hood followed by ster-
ilization. These are called
SIP connectors
. Two aseptic systems go through
sealing using these connectors following sterilization by autoclave, radia-
tion, or chemical treatment. Examples of these SIP connectors are from Coler
(
www.coler.com
) and EMD Millipore (www.millipore). The Lynx ST system
from EMD Millipore comprises an integrated valve, which can be opened
and closed after sterilization of the connection.
Aseptic Connectors
Critical to effective disposable processing operations are aseptic connection
devices. Pharmaceutical manufacturers typically make about 25,000 aseptic
connections each year, with some large manufacturers making as many as
100,000 aseptic connections annually.
The most convenient connectors are aseptic connectors that allow aseptic
connections in an open uncontrolled environment without using a laminar
flow hood. Examples of these aseptic connectors include the offering from
Pall, Sartorius-Stedim, GE Healthcare, EMD Millipore, and Saint-Gobain.
The aseptic parts on the connector side are sealed with sterile membrane fil-
ters or caps. After coupling, the sterile membrane filters must be withdrawn,
and both parts have to be clamped or fixed. These connectors are secure and
recommended to save time but offer an expensive choice and at times there
is a limitation of sizes of tubes that can be connected. These connectors are
also used as aseptic ports in bioreactors.
