Trunnions

Fig. 8. Steel ladle (a) vertical section through the trunnions, and (b) side view.

Figure 12-61 also illustrates three basic types of trunnion rollbearing assemblies. Antifriction pihow blocks are the most common on modern diyers however, when the dryer load requires larger than a 12.7- to 15.2-cm-diameter bearing on the trunnion shaft, the dead-shaft antifriction bearing is substituted. This represents a considerable cost saving compared with the larger pillow blocks. They are completely sealed and continuously bathed in lubricant. Pillow-block bushings are less often used. The thrust washers are difficult to seal against dust, and they draw more power. Thrust roll mountings are depicted also in Fig. 12-61. These are usually dead-shaft.

FIG. 12-61 Rotary-dryer components, a) Alternative rotary gas seals, (h) Alternative trunnion roll bearings, (c) Thrust roll assembly. (ABB Raymond/Battlett-Snow TM.)... 

Stokes Vacuum, Inc. Price includes dryer, 15-lVin jacket, drive with motor, internal filter, and trunnion supports for concrete or steel foundations. Horsepower is established on 65 percent volume loading of material with a hulk density of 50 Ih/ft. Models of 250 ft, 325 ft, and 400 ft have extended surface area. 

All drum filters (except the single-compartment filter) utilize a rotary-valve arrangement in the drum-axis support trunnion to facih-tate removal of filtrate and wash hquid and to allow introduction of air or gas for cake blowback if needed. The valve controls the relative duration of each cycle as well as providing dead portions of the cycle through the use of bridge blocks. A typical valve design is shown in Fig. 18-121. Internal piping manifolds connect the valve with various sections of the drum. 

Wash sprays may be applied to the cake, with collection troughs or pans inserted inside the drum to keep the wash separate from the filtrate. Filtrate is removed from the lower section of the drum by a pipe passing through the trunnions. 

Drum Separators Very coarse solids, up to 0.3 m (12 in), are often processed in a drum separator of the type shown in Fig. 19-32. This is similar to a ball-mill shell with hfters permanently attached to the wall. Medium and feed enter at one end, and the float product flows out through the discharge trunnion, while the sink is lifted by the rotation of the drum to a stationaiy launder, through which it is flushed out. Modifications of this type include division of the shell into two compartments, which permits simultaneous operation at two different piup densities resulting in various grades of products. The two-compartment revolving drum is illustrated in Fig. 19-32. 

Mill feeders attached to the feed trunnion of the conical mill and used to pass the feed into the mill without backspill are of several types. A feed chute is generally used for diy grinding, this consisting of an inclined chute which is sealed at the outer edge of the trunnion and down which the material slides to pass through the trunnion and into the mill. A screw feeder, consisting of a short section of screw conveyor which extends partway into the opening in the feed trunnion and conveys the materi into the mill, may also be used when diy... 

Joy Denver Equipment Div Manufactures a variety of grinding mills. Designs incorporate cast steel heads, hea y rolled steel shell, replaceable cast steel trunnions, hydraiilic starting lubricator, inter-... 

Fig ure 5-15. The inlet support, with the trunnion blocks, supports the inlet casing and is designed for thermal expansion of the casing while maintaining the centerline of the unit. 

The slow rotation of the drum and reciprocation of the agitator reduce maintenance requirements to a minimum but the following should be inspected periodically. The strip liner of the trunnion bearing at the valve end will normally wear at the lower half. However, in situations when the slurry has a high specific gravity, the drum has a tendency to become buoyant causing wear to the upper half. 

A drum that is supported by a large diameter trunnion on the valve end and a bearing on the drive end and its face is divided into circumferential sectors each forming a separate vacuum cell. The internal piping that is connected... 

Lever through 8", Gear Operated 10" and larger 2"-4" Floating Ball, Regular Port 6" and larger Trunnion Mounted Ball, Regular Port Trim Construction Renewable Seats, Removable Stem, Fire Safe... 

Zapfen, m. peg, pin, plug, stud, pivot tap, spigot, bung journal, trunnion tenon cone,... 

Ton cylinders on trunnion, including pigtails, (subheader lines) to main header lines... 

In its simplest form, the ball mill consists of a rotating hollow cylinder, partially filled with balls, with its axis either horizontal or at a small angle to the horizontal. The material to be ground may be fed in through a hollow trunnion at one end and the product leaves through a similar trunnion at the other end. The outlet is normally covered with a coarse screen to prevent the escape of the balls. Figure 2.27 shows a section of an example of the Hardinge ball mill which is also discussed later in this chapter. 

Both floating and trunnion-mounted designs are available with other design variations that include metal seied valves, soft seated valves, top-entry valves, end-entry valves, and split body valves. Valves in all these design variations are available as either full port or reduced port. Port refers to the round-bore fluid flow area through the ball. Full port valves have a bore that is approximately equal to the inside diameter of the mating pipe. Reduced port valves have a bore that is approximately equal to the inside diameter of pipe one size smaller than full bore. 

Value for bottom feed filters assume no trunnion stuffing boxes, except for precoat. Consult manufacturers for availability of higher submergences. 

Integral pipe attachments are welded directly to the pipe and are usually of special design. They are used in high temperature services, with moderate or severe loads, and in conjunction with supports, braces, and restraints where rigidity with the pipe shell is desired. Integral attachments may be grouped into five types ears, lugs, shoes, cylindrical trunnions., and skirts (see Fig. 8). 

Cylindrical trunnions are of more favorable contour for stress distribution and frequendy are used in high temperature services. Their load-carrying capacity is high and their structural effect on the pipe shell can easily be determined. 

Skirts are used in vessels and towers. They transmit high axial and bending loads and offer favorable geometry for thermal gradients. In piping, when loads are beyond the capacity of lugs and trunnions, skirts are often favored. 

---