Machinery's Handbook, 31st Edition
Sheet Metal Joints
1447
Clinch-bar Slip and Angle :
The clinch-bar slip and angle (Fig. 55), is similar to clinch bar slip (Fig. 54), but it has a riveted or spot-welded angle on the large end. This connection can also have a raw large end that is inserted into the space between the angle and the shop-fabricated slip. Matched angles, minimum of 16-gage (1.52 mm), are riveted or spot-welded to the smaller sides of the ducts to pull the connection “home.” Flanged Duct Connections Any of the following flanged connections may have gaskets. The drafter should not allow for gasket thicknesses in calculations for running length dimensions, nor indicate angle sizes, bolt centers, etc., as these items are established in job specifications and approved shop standards. Generally, angles are fastened to duct sections in the shop. If conditions at the job site require consideration for length contingencies, the drafter should specify “loose angles” such as at a connection to equipment that may be located later. The most common matched angle connection is the angle frame , or ring (Fig. 56 ). The angles are fastened flush to the end of the duct. The flanged end and angle (Fig. 57), is often used for ducts 16 gage or lighter, as the flange provides a metal-to-metal gasket and holds the angle frame or ring on the duct without additional fastening. The drafter may indicate in a field note that a round-duct fitting is to be “rotated as required”. This type of angle-ring-connection is convenient for such a condition. Double flanges (Fig. 58), are similar to Fig. 46, except that the con necting flange has a series of matched bolt holes. This connection, caulked airtight, is ideal for single-wall apparatus casings or ple nums. The flanges are formed at the ends of the duct; after assembly they will form a T shape. Mating flanges shall be locked together by long clips. In order to form an effective seal, gaskets with suitable density and resiliency are used. At the corners 16 gage (1.5 mm) thickness steel corners are used with 3 ∕ 8 inch (9.5 mm) diameter bolts.
Fig. 55. Clinch-bar Slip and Angle
Angle Frame, or Ring:
Fig. 56. Raw Ends and Matched ∠ s Flanged End and Angle:
Fig. 57. Flanged Ends and Matched ∠ s
Formed Flanges:
Fig. 58. Formed Flanges Double Flanges and Cleat:
Double Flanges and Cleat (Fig. 59) is identical to (Fig. 58), but has an air seal cleat. The reinforcements are attached to the duct wall on both sides of the joint.
Fig. 59. Double Flanges and Cleat
Clinch-type Flanged Connections:
Clinch-type flanged connections for round ducts, 16 gage or lighter, are shown in Fig. 60. The angles or rings can be loose, as explained in Flanged End and Angle , (Fig. 57). The drafter should indicate flange sizes, bend direction, and type of assembly. An example such as the flange lap for a field assembly of a 10 gage (3.4 mm) casing corner would be written: 1 1 ∕ 2 inches (38 mm) flange out square on side with 9 ∕ 32 inch (7 mm) ∅ bolt holes 12 inches (30 cm) CC. At the beginning and ending, angles are connected by rivets or welding. The bolt will be 5 ∕ 16 inch (8 mm) ∅ at 6 inch (152 mm) maximum spacing.
Fig. 60. Bead Clinch and Z Rings
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