Packed glands

Polytetrafluoroethylene (PTFE) provides the most satisfactory electrical insulation. Concentric rings of PTFE and PTFE impregnated with calcium fluoride are used for the packing glands which support the anode and cathode posts. Rubber is used as the gasket material to form a seal between the cover... 

When wet, volatile, or hazardous gases are handled or when the service is intermittent, an auxihary packing gland and soft packing are usually employed (see Fig. 10-98). 

Other Types of Piping Joints Packed-gland joints (Fig. 10-135) require no special end preparation of pipe but do reqmre careful control of the diameter of the pipe. Thus the suppher of the pipe shoiild be notified when packed-gland joints are to be used. Cast- and ductile-iron pipe, fittings, and valves are available with the bell cast on one or... 

On initial start-up and shut-down the heat exchanger can be subjected to damaging thermal shock, overpressure or hydraulic hammer. This can lead to leaky tube-to-tubesheet joints, damaged expansion joints or packing glands because of excessive axial thermal, expansion of the tubes or shell. Excessive shell side flowrates during the "shake down can cause tube vibrations and catastrophic failure. 

Bolted to Shell Packing Gland at Tube Sheet... 

Sheli Cover Bolted to Shell. Shell Cover Bolted to Shell. Floating Head Caver Baited ta Floating Head Cover Boited Tube Sheet or its Backing Ring. Expansion of Tube Bundle to Tube Sheet or its Provided by External Packing Gland or by Internal Bellows... 

See Figure 12-9. The pressure seal between the cylinder pressure and the crank case or atmosphere is maintained by a packing gland. 

Adiabatic Shaft Efficiency. The adiabatic and polytropic efficiencies do not include the losses of packing glands, oil pump, journal bearings, thrust bearings, etc. To account... 

The stuffing box, or packed gland, has been used for many years, typical layouts being shown in Figure 32.60. Usually, since a very smooth shaft surface is needed a... 

The mechanical seal is now a standard fitting of high reliability and tends to be fitted instead of a packed gland. A typical mechanical seal is shown in Figure 32.63. The... 

If a mechanical seal or a packed gland is fitted properly, a good life can be expected if the liquid is clean. If grit is in suspension, the seal manufacturer should be consulted about appropriate materials and system design. 

As in the compressed packing gland, lubrication also must be provided in mechanical seals. The sealing area surfaces should be lubricated and cooled with pumped fluid (if it is clean enough) or an outside source of clean fluid. However, much less lubrication is required with this type of seal because the frictional surface area is smaller... 

Badly worn machinery, tight packing glands, badly adjusted drive belts, etc., leading to wastage of drive power... 

Check all circulating pumps for leaks around packing, glands, or mechanical seals and replace or tighten as necessary. 

The simplest, and oldest, form of seal is the packed gland, or stuffing box, Figure 5.12. Its applications range from sealing the stems of the water taps in every home, to proving the seal on industrial pumps, agitator and valve shafts. 

Figure 5.13. Packed gland with lantern ring...

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