Suez Sievers UPW Boron Analyzer, Operation And Maintenance Manual

Page: 90 / 104

SUEZ © 2018 90 of 104 DLM 71000-03 EN
Rev. B
Chapter 8: Maintenance
Figure 14: John Guest Fitting (x-ray view)
1/4-28
This type of fitting is used to connect 1/16-inch OD and 1/8-inch OD tubing in many places in the Analyzer.
Tubing materials include rigid plastic (PEEK) and stainless steel. The fitting body has a flat bottom, which
seals to the flat face of the ferrule. The PEEK nut screws into the fitting body via 1/4-28 threads and
compresses the ferrule, thereby sealing the ferrule to the tubing and to the fitting body. Ferrules for 1/8 inch
tubing are one-piece, whereas ferrules for 1/16-inch tubing consist of two parts - a steel ring and a plastic
ferrule. The steel ring goes between the plastic ferrule and the PEEK nut. Replacement tubing assemblies
will have these ferrules already installed onto the tubing. The 1/4-28 fittings have plastic fitting bodies; do
not over-tighten the PEEK nut or the threads in the fitting body may be damaged.
Swagelok
The pressure regulator assembly has 1/8-inch Swagelok
®
connections. The sample line filters have
1/4 inch Swagelok connections. These are the only fittings in the Analyzer that require tools; you will need
7/16-inch wrenches for the 1/8-inch Swagelok connections and 9/16-inch wrenches for the sample line
filters. This type of fitting uses a nut with internal threads to compress a two-piece ferrule that seals the
tubing to the fitting body, which has external threads and a conical surface that seals to the ferrule. Be
careful not to overtighten this fitting, especially when the tubing is plastic.
Rheodyne
The Rheodyne
®
type of fitting is used on the injection valve and the reagent tee (node between V2, V3 and
V1-4). No tools are required to make or break connections. The PEEK nut has a built-in PEEK ferrule that
seals the 1/16-inch OD tubing to the fitting body. The reagent tee is PEEK, whereas the injection valve is
aluminum. Be sure the fine threads of the PEEK nut are not cross-threaded in the fitting body when making
a connection. This type of fitting is used in these places because it makes a zero dead volume seal; ensure
the tubing is fully inserted into the fitting body before tightening the PEEK nut, in order to affect the zero
dead volume seal.