Rotary shaft seals

Graphites (natural or synthetic) are black semireinforcing fillers used almost exclusively in rotary shaft seal applications where surface lubricity and abrasion resistance must be enhanced (see Carbon, natural graphite). 

An alternative approach for injection molding is the use of a rotary table injection machine. This type of machine uses the multistation concept, each station having a single cavity mold generally using a point gating/ injection point as previously mentioned. Consider a rotary table machine with eight stations, station one would be the injection station and station seven would be the unload and load metal insert station. This type of process has been successfully used for different types of lip type rotary shaft seals where more expensive elastomers are used and waste needs to be kept to a minimum. 

Ferrofluids find several technical applications, which include rotary shaft seals, damping fluids, accelerometers, optical switches and shutters, and magnetic inks. The earliest application was in the construction of wear-free seals for rotary shafts. A similar seal is used in computer disc drives. Using ferrofluids, high-pressure differential seals which work in multiple stages have been constructed. When the seal is pressurized, each stage develops a momentary leak into the next chamber. The total pressure that can be contained is the sum of the pressure differences across all the stages. Pressure seals... 

JAGGER, E.T. and WALKER, P.T. Further studies of the lubrication of synthetic rubber rotary shaft seals, Proc, Instn. 

The cell was supported on an alumina platform suspended from a hoist fitted with a rotary shaft-seal. By means of the hoist, the cell, without being opened to air, could be lifted out of the work-tube into a chamber sealed to the top of the work-tube. This enabled the work-tube to be outgassed by heating in vacuo before the cell was lowered into the hot-zone, and also enabled the cell to be cooled down and the electrodes replaced, without cooling the furnace to room temperature. After outgassing the system was filled with purified argon. 

The crankcase seal is a rotary shaft seal preventing the loss of oil from the crankcase via the drive shaft. The temperature at the lip of such seals is... 

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. 

Factiiring in general, we observe that there are more eentrihigal pumps. About 90% of the pumps in industry are eentrifugal pumps. And the PD pumps found in industry have much in common with their eentrifugal sisters. They are mostly rotary designed pumps, with precision bearings and a shaft seal. Much of the theory, and system needs, are applicable to both types of pumps. 

Figure 13-17 shows a balanced, single, rotary dement seal mounted onto the pump shaft, pressed against the stationary face and gland, mounted in the seal chamber. Note the individual component parts of the rotary element. 

A. S. Berensand J. H. Born, The Effect of Surface Microstructure on the Performance of Rotary Shaft Lip Type Oil Seals. Fourth Rubber and Plastics Conference, July 4-7 (1974). 

L. A. Horve, The Correlation of Rotary Shaft Lip Seal Service Reliability and Pumping Ability to Wear Track Roughness and Microasperity Formation. S.A.E. Paper 910530 (1991). 

Standard 682 Shaft Sealing Systems for Centrifugal and Rotary Pumps... 

API Std 682 Shaft sealing systems for centrifugal and rotary pumps ... 

Lever and Shaft Mechanisms In pressurized vessels, float-actuated lever and shaft mechanisms are frequently used for level measurement. This type of mechanism consists of a hollow metal float and lever attached to a rotary shaft which transmits the float motion to the outside of the vessel through a rotary seal. 

Most screw compressors are of the oil-lubricated type. There are two types—the semihermetic and the open-drive type. In the former, the motor is located in the same housing as the compressor, while in the latter the motor is located outside of the compressor housing and thus requires a shaft seal. The only moving parts in screw compressors are two intermeshing helical rotors. The rotors consist of one male lobe, which functions as a rolling piston, and a female flute, which acts as a cylinder. Since rotary screw compression is a continuous positive-displacement process, no surges are created in the system. 

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