Hamilton sensor holders often mention o-ring position (OP). Selecting the proper OP helps ensure a good seal with the safety socket as well as minimizing dead-space where contaminants can hide out.

In many bioprocesses the G 1¼” process connection (sometimes referred to as a 25mm InGold connection) is very common. The OP is measured from the flange on the sensor holder to the bottom of the o-ring on the body of the holder.

Examples of different o-ring positions (OP) for the Flexifit Bio Sensor Holder. This product can be ordered with OP from 22 to 55mm

The safety socket length should match the OP of the holder. This puts the o-ring nearly flush (<1mm) with the end of the socket. If the OP is longer then the socket then no seal will occur. If the OP is shorter than the socket there will be excessive dead-space and the potential for poor or no sealing as well. For angled safety sockets the length is based on the shorter side of the socket as shown below.

The angled socket shown above measures the sealing surface based on the shorter side measured at the top of the socket