Dual laminate fabrication

Dual laminate Same as adhesively bonded Fabricate liner first Pressure ok 33 diameter Visual Possible... 

Dual Laminate (Fluoropolymer-lined FRP) Same as Adhesive-bonded Fabricate liner first on a mandrel (hand and machine welding) and build FRP laminate over the liner. Use carbon cloth for spark testing Shop and Field Pressure OK (RTP-1 Dual lam) Vacuum OK for FRP/fluoropolymer bond. Design FRP for vacuum 33 dia max Visual Spark AE CRBBD Possible Testing recommended... 

The principle of dual laminate construction is to line an FRP vessel or column with a fluoropolymer lining. However, the sequence of construction is to first make the liner out of fabric-backed sheets the same as in the adhesively bonded construction. The FRP structure is then laminated on the liner to pro-... 

Figure 8.25 shows an operator working on laminate fabrication. Figures 8.26 and 8.27 illustrate the fabrication technique and examples of dual laminate structures. The job sequence is as follows ... 

Figure 8.25 Dual laminate flange fabrication. (Courtesy CPF Dualam.)...

The chlorine headers popular in Europe are dual laminate headers, which are preferred over FRP for environmental reasons. The dual laminate has an inner ring of less brittle PVC-C of 5-mm thickness for corrosion protection and an outer layer of 10-15 mm thickness of FRP for structural strength, the intermediate layer being 5 mm of resin-rich FRP 5 ION or 197-3. The outer layer contains a flame retardant and is added after the dual laminate is stress relieved. The chlorinated PVC (CPVC)/FRP dual laminate header is fabricated from CPVC tubing up to 60 cm in diameter. The dual laminate headers have a life of 8-10 years vs the 6-12 years of life of FRP, at a comparable cost. 

Dual laminate structures are composed of fiber reinforced plastic (FRP) built with fiuoropolymer sheeting that serves as a lining. This lining is fabricated by machine and hand welding of fiber backed fiuoropolymer sheets, like those described above for adhesive bonded systems. The fabric aids in bonding the sheeting to the FRP. 

FRP piping lined with fluoropolymer is manufactured by forming FRP over a fluoropolymer tube. The resulting structure is a called a dual laminate. Typically, this tube is a thermoplastic fluoropolymer such as PFA or FEP so that glass fabric can be readily embedded in its outer wall. This fabric bonds with the FRP structure so that the lining is held firmly in place. 

Dual layer hollow fiber membranes have become increasingly attractive due to which they can be fabricated in a single step using the non-solvent induced phase inversion method. A good lamination between the two layers as well as a regular morphology are critical to get a functional hollow fiber membrane [80]. 

Alternating layers of two different materials with different laminate thickness in the range of nanometers can be fabricated by electrochemical deposition. This technique demonstrates the capabiUty of the relatively inexpensive process of electrodeposition for the production of advanced materials with ultrafine microstmcture (Schwarzacher et al, 1997). Electrodeposition of multilayers can be carried out using either a single or dual bath approach. In dual bath electrodeposition the substrate is transferred to suitable electrolytes during the deposition of each layer. A single bath is a more desirable process and compositional modulation of the layers can be achieved by prdsing the current or potential. 

Fabrication of dual-layer membranes either in hollow-fiber or flat-sheet configuration is rather complex as many parameters are involved, which control the thermodynamic property and the phase inversion kinetics to obtain good lamination between the two layers as well as regular and uniform membrane cross-sectional morphology. Fabrication parameters can be classified into the chemistry of polymer solutions and the operating conditions. The chemistry of polymer solutions depends on the polymer concentration and type, the solvents affinity to the polymer or coagulant, and... 

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