Sandwich flanges and potted seals are inherently flawed. Sandwich flanges are difficult to assemble because you must hold the 24 loose sensor wires separated from one another while holding and aligning the two flanges and two rubber sealing disks while inserting and tightening the four sets of bolts, nuts, washers, and lock washers with two wrenches. Accomplishing this feat is extremely difficult, even with multiple people and must be repeated every time you have to change a broken sensor wire.
It is also very difficult to get a good seal between the two rubber disks and the sensor wires without tightening the assembly to the point of crushing and damaging the sensor wires. The sandwich flange cannot be used in high vacuum applications such as lyophilizers and definitely should not be used on Ethylene Oxide sterilizers where even leaks resulting in part-per-million concentrations outside the chamber cannot be tolerated.
Some recent attempts to modernize the sandwich flange have made it slightly easier to assemble but have not cured the leakage problems. It is still very difficult to get a good seal between the two flat rubber disks and the sensor wires without tightening the assembly to the point of crushing and damaging the sensor wires.
Creating a potted seal is easier than assembling a sandwich flange, but RTV rubber or epoxy take a long time to repair and the resulting seals are impossible to repair. Broken sensor wires cannot be removed without the risk of damaging other sensor wires. A broken sensor could force you to discard an assembly worth thousands of dollars.
Potted seals also present a safety concern. The RTV rubber and epoxy soften at sterilization temperatures and could be forced out of the metal retaining cylinder with catastrophic results due to the pressure inside the sterilizer. Rigid epoxies present other problems. With multiple uses the heating and cooling of the assembly can cause the bonds between the epoxy and wire insulation and the epoxy and the metal cylinder to rupture and form leaks that are impossible to permanently repair. The first heat/cool cycle will usually reopen the leaks.
The Skyl-Tech PV-Seal FEEDTHRU solves all of these problems.