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Using Tubes, Bottles, and Accessories
Capping Tubes
Blue-anodized. Aluminum caps with blue-anodized crowns are used with thickwall polypropylene
and polycarbonate tubes for centrifugation at their maximum fill volumes in high-performance
rotors. The cap nut should be tightened with a torque wrench while the tube is held in the tube-cap
vise.
Clear- and black-anodized
• Clear-anodized crown aluminum caps that use O-rings for sealing are used in many rotors with
many types of tubes. Refer to Table 3.3. The caps should be hand tightened with a hex driver
while the tube is held in the tube-cap vise (refer to Assembling Tube Caps, below).
• Aluminum caps that use flat gaskets for sealing are used with small-diameter (13-mm) thinwall
Ultra-Clear and polypropylene tubes in all fixed-angle rotors except Types 42.2, 25, and 19.
They are also used with stainless steel tubes. Some caps for very small-diameter (less than
13-mm) tubes do not have filling holes (nylon insert or setscrew). The tube crown is made from
a lighter-weight aluminum alloy than that used for other clear aluminum caps; therefore, do not
interchange cap parts or use these caps in place of O-ring caps, since the weight difference can cause
rotor imbalance. The caps should be hand tightened with a hex driver while the tube is held in
the tube-cap vise.
• Caps for thickwall tubes used in Type 21 rotors have Delrin crown washers and must be tightened
with a torque wrench.
• Caps for thickwall tubes used in Type 30 rotors have black-anodized crowns and use neoprene
O-rings for sealing. These caps have Delrin crown washers and must be tightened with a torque
wrench.
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LR-IM-24AC