amics.org/lAGS Glass Fiber-Reinforced Composites Table Il. Pressure Vessel Types, Construction, and Cost-Performance Type 1 Type 3 f Market share(%) 93 Metal Metal liner reinforced Metal liner reinforced with Resin impregnated with resin impregnated resin impregnated continuous continuous filament continuous filament filament(full wrap) with a nonmetallic (hoop wrap Most commonly CrMo steel CrMo steel with glass Aluminum with HP glass HDPE liner with fiber or carbon carbon Indicative $3 to S5 $5 to S7 $9 to $14 S11 to $18 ost -USS/L Indicative 0.91 0.81.0 04-0.5 0.3-0.4 ture, but are the heaviest. Types 24 are composite vessels. Type 2 vessels have a heavy liner and utilize Rovin Tensioner composite rel nforcemer nt only in the hoop or circum ferential Types 3 and 4 have a full compos supply Resin bath ite overwrap, providing both circumferential and axial inforcement. The difference between Type 3 and 4 is in the liner. Type 3 cylinders have a metal(typically Tool Shuttle Axle aluminum) liner that may share a small fraction of the internal pressure load. Type 4 cylinders have a plastic (typically high-density polyethylene [HDPE) liner that serves only as a substrate for the load-bearing compos ite. In general, in order from Type I to Type 4, as Type number increases, price increases, and weight Semi-finished decreases. The indicative cost data in the table ii will component Track ange with raw material prices, but the relative cost ratios between the four vessel types should remain fairly Fig. 8. Filament winding proces schematic c Filament Winding Process by Owens Corning in the 1960s. A schematic of the filament winding process is given in Fig. 8. Rovings Before discussing why composites work in pressure are fed through tensioning devices to a resin impregna- vessel applications, it is of value to discuss how compos- tion bath. Impregnation is achieved either by feeding ite pressure vessels are made. Steel liners are made from rovings through the bath or by feeding them over a blanks using a deep draw process. Aluminum liners can metering roll that rotates through the bath to pick up a be made from blanks, but are more typically made from defined amount of resin. The impregnated rovings are seamless extruded tube stock. Ends are heat spun to then gathered together and placed onto the rotating shape into hemispherical domes, and in most cases, part in a high-precision, computer-controlled process necks are formed in the same processing step so that The number and tex of rovings used depends on the tire end cap is one piece. For Type 4 tanks, HDPE size of the part to be fabricated and the width of the liners are made by blow molding or rotational molding. band desired. mposite outer layer is created using filament A single-axis(or axle) winder would be adequate ding, a continuous fiber process that was developed for making Type 2 vessels, but a multi-axis winder isture, but are the heaviest. Types 2–4 are composite vessels. Type 2 vessels have a heavy liner and utilize composite reinforcement only in the hoop or circum￾ferential orientation. Types 3 and 4 have a full compos￾ite overwrap, providing both circumferential and axial reinforcement. The difference between Type 3 and 4 is in the liner. Type 3 cylinders have a metal (typically aluminum) liner that may share a small fraction of the internal pressure load. Type 4 cylinders have a plastic (typically high-density polyethylene [HDPE]) liner that serves only as a substrate for the load-bearing compos￾ite. In general, in order from Type 1 to Type 4, as Type number increases, price increases, and weight decreases. The indicative cost data in the Table II will change with raw material prices, but the relative cost ratios between the four vessel types should remain fairly constant. Filament Winding Process Before discussing why composites work in pressure vessel applications, it is of value to discuss how compos￾ite pressure vessels are made. Steel liners are made from blanks using a deep draw process. Aluminum liners can be made from blanks, but are more typically made from seamless extruded tube stock. Ends are heat spun to shape into hemispherical domes, and in most cases, necks are formed in the same processing step so that entire end cap is one piece. For Type 4 tanks, HDPE liners are made by blow molding or rotational molding. The composite outer layer is created using filament winding, a continuous fiber process that was developed by Owens Corning in the 1960s. A schematic of the filament winding process is given in Fig. 8.10 Rovings are fed through tensioning devices to a resin impregna￾tion bath. Impregnation is achieved either by feeding rovings through the bath or by feeding them over a metering roll that rotates through the bath to pick up a defined amount of resin. The impregnated rovings are then gathered together and placed onto the rotating part in a high-precision, computer-controlled process. The number and tex of rovings used depends on the size of the part to be fabricated and the width of the band desired.11 A single-axis (or axle) winder would be adequate for making Type 2 vessels, but a multi-axis winder is Fig. 8. Filament winding process schematic.10 Table II. Pressure Vessel Types, Construction, and Cost-Performance9 Type 1 Type 2 Type 3 Type 4 Market share (%) 93 4 <2 <2 Structure Metal Metal liner reinforced with resin impregnated continuous filament (hoop wrap) Metal liner reinforced with resin impregnated continuous filament (full wrap) Resin impregnated continuous filament with a nonmetallic liner Most commonly used CrMo steel CrMo steel with glass fiber Aluminum with HP glass or carbon HDPE liner with carbon Indicative cost -US$/L $3 to $5 $5 to $7 $9 to $14 $11 to $18 Indicative weight -Kg/L 0.9–1.3 0.8–1.0 0.4–0.5 0.3–0.4 www.ceramics.org/IJAGS Glass Fiber-Reinforced Composites 129