SLEEVE INSTALLATION |
Tubes should be clean from all debris and the tube ends free of dings, weld spatter, ect. The parent tube is prepared for sleeve installation – measurements are reconfirmed as correct on the parent tube I.D. surface and sleeve. A sleeve is installed onto the sleeving tube – Expansion pressure is brought to 2000 PSIG to lock sleeve on installation tooling. The sleeve is installed into the parent tube section and set to the predetermined position (Flush or protruded). The sleeve is raised to its expansion/yield pressure where the stress pressure begins to yield the tube and reacts in a fully elastic condition. The sleeve is brought to its interference pressure (IP). The sleeve is held as it’s IP for a predetermined time (Dwell Time) during which there is elastic material recovery (Spring back). The pressures are released and installation tool removed. The flared sleeve end is rolled into the parent tube (Soft Roll). The straight sleeve end is expanded to the tube parent tube. |
NOMENCLATURE |
Load pressure – 2000 PSIG Yield Pressure – Calculated and field tuned (8000 PSIG - .750 X .030 wall – 316l Stainless Steel) Interference fit pressure - Yield pressure + 1000 PSIG Tube O.D. – (Eg – .1” O.D.) Tube I.D. – (Eg. – .782 I.D.) Tube wall Thickness – (Eg. - .109) Tube Material – (Eg. – SA-178) Sleeve O.D. – (Eg. – .593” O.D.) Sleeve I.D. – (Eg. – .495” I.D.) Sleeve wall thickness – (Eg. – .049”) Sleeve Material – 316 L Stainless steel) |
PROCEDURE for HYDRO-EXPANSION |
View of Finfan being sleeved due to severe inlet thinning – Sleeve length 2’ |
View of process gas cooler in sleeving process – Sleeve length 3’ |
Full length sleeve expansion 921 tubes completed in 27 hours |
Correct design information is required to insure a high strength sleeve to tube joint by the use of hydro-expansion techniques. The frictional interference fit between the installed sleeve and the parent tube produced by hydro-expansion is governed by many variables. These variables are listed below. |
It should be noted that specific tube heats may vary the expansion to a great degree. Calculated and actual expansion pressures might be different and the calculated pressure is meant as a guide line for installation. Determination of the actual field installing pressure are to be determined by calculated and field tuned pressures that yield the proper fit. |
Sleeve expansion develops interference fit pressure that expands the sleeve for its entire length within the parent tube. The appropriate calculation’s for specific material yields, material compatibility, and sleeve installation pressure are reviewed prior to sleeve installation to insure proper fit. Expansions of the sleeve test coupons are shown to have wall reductions of between 2% and 5%. These wall reductions are approximately 1/3rd to 1/2 of the wall reductions found in hard rolled tubes. |
Thorough review of corrosion mechanism, location and extent allow for the sleeving of tubular process equipment to be fully effective. The correct sleeve metallurgy being selected, the sleeve being positioned within the corrosion area and the correct sleeve length to cover the corrosion area must all be considered when planning a sleeve operation. |
Conditional analysis of heat transfer tubing is a major concern due to budgeted funding, repair, retube, and or modification of your heat transfer equipment to return it to 100 percent capacity. For this reason a comprehensive Eddy Current inspection should be performed to allow your plant personnel to make wise decision's concerning tubular equipment. |
Heat Exchanger Tube Sleeving |
Photo |
FINFAN |