RECIPROCATING SEAL

Reciprocating seal a dynamic seal used to seal pistons or rods that are in linear motion. 

The amount of previously published information on theoretical and experimental aspects of IsovlscouB-elastohydrodynamlc lubrication Is very limited, especially for the unusual geometries considered here. Several authors have produced theoretical results for the line contact problem, but very little experimental work has been published. Hlgglnson (14), and Dowson and Swales (9,15) considered the problem of the Isovlscous-elastohydrodynamlc lubrication of reciprocating seals, both experimentally and theoretically. A simplified theoretical analysis of the line contact problem existing In human ankle Joints was described by Medley and Dowson (13), who modelled the joint by both a cylinder near a plane and by an equivalent plane Inclined surface to allow squeeze effects to be Included more readily. 

Elastohydrodynamlc Approach to the Problem of the Reciprocating Seal., The Third International Meeting on Fluid Sealing, British Hydrodynamics Research Association, 1967, 33-44. 

Dowson D. and Swales P.D., The Development of Elastohydrodynamlc Conditions in a Reciprocating Seal., ... 

Eleaent Calculation of the Elastohydrodynaaic Behaviour of a Reciprocating Seal, Proc. of the Ninth Int. Conf. on Fluid Sealing 1981, 403-412, (BHRA Fluid Engineering, UK.)... 

The major difficulty with these reactors is in the outside recycle pump, especially at high temperatures. Reciprocating pumps require seal rings, and these cannot take the high temperature needed for most reactions. If the recycle gas is cooled down before entering the compressor, it must be reheated before it enters the reactor again. This makes them complicated in construction and excessive in cost. 

If a gas leak test is called for, the test can take place shortly after the hydrotest, especially on the reciprocator cylinder or centrifugal or rotary compressors, where the gas is tested without end seals. 

Static seals are standard provision from many suppliers therefore seals for the moving elements in pumps will be discussed. For centrifugal pumps, both stuffing box and mechanical seals will be considered and the discussion will be extended to reciprocating and rotary machines. 

The only other variables that affect performance are the inlet-discharge valves, which control flow into and out of each cylinder. Although reciprocating compressors can use a variety of valve designs, it is crucial that the valves perform reliably. If they are damaged and fail to operate at the proper time or do not seal properly, overall compressor performance will be substantially reduced. 

In oxidizing, oil becomes thicker and it deposits carbon and gummy, resinous substances. These accumulate in the piston-ring grooves of reciprocating compressors and in the slots of vane-type units, and as a result, they restrict free movement of components and allow air leakage to develop. The deposits also settle in and around the valves of piston-type compressors, and prevent proper sealing. 

Nitrile rubbers, including fiber-reinforced varieties, are used both as radial shaft-seal materials and as molded packing for reciprocating shafts. They have excellent resistance to a considerable range of chemicals, with the exception of strong acids and alkalis, and are at the same time compatible with petroleum-based lubricants. Their working temperature range is from —1°C to 107°C (30°F to 225°F) continuously and up to 150°C (302°F) intermittently. When used on hard shafts with a surface finish of, at most, 0.00038 mm root mean square (RMS), they have an excellent resistance to abrasion. 

This procedure provides detailed instructions on how to repack centrifugal pump packed stuffing boxes or glands. The methodology described here is applicable to other gland sealed units such as valves and reciprocating machinery. 

The piston is driven in and out of a solvent chamber by an eccentric cam or gear. On the forward stroke, the inlet check valve closes, the outlet valve opens, and mobile phase is pumped to the column on the return stroke the outlet valve closes and the chamber is refilled. Unlike syringe pumps, reciprocating pumps have an unlimited capacity, and their internal volume can be made very small, from 10-100 p. The flow rate can be varied by changing the length of stroke of the piston or the speed of the motor. Access to the valves and seals is usually fairly straightforward. 

Piston meters, reciprocating, 11 655 Piston seals, in high pressure apparatus, 13 415... 

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