Lantern ring, the

An effective auxiliaiy device frequently used with packing and rotary shafts is the seal cage (or lantern ring), shown in Fig. 10-110. The seal cage provides an annulus around the shaft for the introduction of a lubricant, oil, grease, etc. The seal cage is also used to introduce liquid for cooling, to prevent the entrance of atmospheric air, or to prevent the infiltration of abrasives from the process liqmd. 

The lantern ring performs three basie hinetions ... 

Oil, water, grease, or any liquid or substance compatible with the tluid are forced under pressure into the paeking through the lantern ring by means of a connection on the stuffing box wall to provide these three hinetions. 

Install the lantern ring in its correct location within the gland. Do not force the lantern ring into position (Figure 56.12). 

Staffing boxes on packed pnmps shall have provision for seal cages (lantern rings) for the introdnction of a cooling medinm directly into the packing. Inlet and ontiet connections shall be provided for the seal cage. 

The Lantern of the Hand at the ring finger is Alum. Properly speaking, Alum is a vitriol being the double sulfate of potassium and aluminum KA1(SC>4)2, but has been such a versatile mineral since ancient times that it s in a class of its own. It has been used for cleaning and deodorizing, as a mordant for dyes, to prepare leather, and as an astringent and styptic to close wounds. 

The packed-lantern-ring construction is generally limited to design temperatures below 191°C (375°F) and to the mild services of water, steam, air, lubricating oil, etc. Design gauge pressure does not exceed 2068 kPa (300 IbFin for pipe shell exchangers and is limited to 1034 kPa (150 Ibf/in ) for 610- to 1067-mm- (24- to 42-in-) diameter shells. 

FIG. 11-36 (Continued) Heat-exchanger-component nomenclature. (/) Exchanger with packed floating tube sheet and lantern ring. Type AJW. (Standards of the Tubular Exchanger Manufacturers Association, 6th ed., 1978.)... 

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