Ferrules tightening

Tubes may be inserted into a tubesheet, and packing may be added between them and the tubesheet. A threaded ferrule is inserted to tighten the packing. This type of joint is used only for special expansion problems. 

Tighten Swagelok joints or remake the joint with new tubing and ferrules. 

The available configurations for these fittings are basically T, cross, straight with options for either all tube ends, or tube to NPT. The tube connecting ends consist of a nut with two sleeves (ferrules) that slip over the tubing. The sleeves are compressed and locked into the tubing by tightening the nut to create a sealed connection. For this type, do not use any thread compound or tape on the tube end connection threaded nut. You can use tape on the NPT side, however. 

Put the ferrules on the Teflon (see top of photo, above), insert into the tubing end of fitting and tighten lock nut slightly (see page 80). 

Place the taped rod with the Teflon insert into the fitting, put on the ferrules and nut, and then tighten. 

Put the tube into the fitting, add the ferrules, slip on the nut and tighten. 

Push the other 2" x %" Yor-Lok fitting on to the 211 tube, slip the ferrules into position and tighten the nut. 

All interconnection pieces, ferrules and fittings should come from one manufacturer, because different brand names may have small differences in their dimensions, leading to a small dead volume and consequently to a deterioration of the anticipated separation (see Tip No. 9). In general, connection fittings should be tightened by feel , since otherwise the screw thread can break off and, in accordance with Murphy s law, will invariably get. stuck inside the detector. If you need to apply force to tighten a leak, please make it gentle force ... 

The most well-known expansion bolt is made by Rawibolt and consists of a split iron shell held together by a steel ferrule at one end and a spring wire clip at the other end. Tightening the bolt draws up an expanding bolt inside the split iron shell, forcing the iron to expand and grip the masonry. Rawibolts are for heavy-duty masonry fixings. 

A hole is drilled in the masonry to take the iron shell and ferrule. The iron shell is inserted with the spring wire clip end first so that the ferrule is at the outer surface. The bolt is passed through the fixture, located in the expanding nut and tightened until the fixing becomes secure. 

Another potential source of trouble is gas leaks in the GC. Diluted detergent solutions may be used to detect them, but tightening the fittings will squeeze the liquid from between the front ferrule and the conus into the gas supply system. This causes sharp peaks as well as baseline drift and variations in detector sensitivity and thus is not encouraged. 

FIGURE 10.19 Ferrule profile reveals correct/incorrect tightening [reprinted with permission of Supelco, Bellefonte, PA 16823 (USA)]. 

Tighten the ferrule locking nut securely with a wrench or spanner, while preventing the packing retaining nut from moving with a second tool. 

---