Ladder pipe

Helical strakes (strips) are fitted to the tops of tall smooth chimneys to change the pattern of vortex shedding and so prevent resonant oscillation. The same effect will be achieved on a tall column by distributing any attachments (ladders, pipes and platforms) around the column. 

Ancillary equipment attached to a tall vessel will subject the vessel to a bending moment if the centre of gravity of the equipment does not coincide with the centre line of the vessel (Figure 13.21). The moment produced by small fittings, such as ladders, pipes and manways, will be small and can be neglected. That produced by heavy equipment, such as reflux condensers and side platforms, can be significant and should be considered. The moment is given by ... 

FIG. 14-68 Pressure liquid distributors, (a) Ladder pipe, (b) Spray. (Courtesy of Koch-Glitsch LP.)... 

Placarding Requirements These are detailed at 49 C.F.R. 172.500-558. Different requirements are specified for rail and highway transport, and for freight containers and tanks. In general, a placard must be readily visible from the direction it faces securely attached to the transport vehicle, tank, or container located away from obstructions such as ladders, pipes, doors, or tarpaulins and have words horizontally displayed. Illustrations for the required shape and design of placards serving specified purposes are also included. 

Located clear of appurtenances and devices such as ladders, pipes, doors and tarpaulins,... 

Figure 3.4 Common types of liquid distributors, (a) Ladder pipe distributor (6) perforated ring distributor (c) spray distributor id) orifice pan distributor (e) tunnel orifice distributor (f) notched-trough distributor (g) weir-riser distributor. (Parts a and c to f reprinted courtesy of Norton Company part b, reprinted courtesy of Koch Engineering Company, Inc. part g, reprinted courtesy ofGlitsch, Inc.)...

Several incidents have been experienced in which small distributor perforations were plugged by scale and dirt (168). In one reported case (346), enlarging the perforation diameter and installing an upstream filter with V64-in openings eliminated a plugging problem in a ladder pipe distributor. 

Petrochemicals Xylene fractionator Reflux entered via a ladder-pipe distributor, and the center bed was irrigated by an orifice distributor, both of standard construction. These were replaced by a lateral arm and orifice deck hi -performance distributors. HETP in the beds was lowered by 20 to 40%. As for 812. 

In design of pristressed concrete water reservoirs or underwater reinforced concrete tuimels for future installation of cathodic protection, all metaUic members of the structure, including wires, reinforcing bars in the walls and the floor, interior ladder, piping, and vertical stressing rods should be bonded together. 

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