Circulating lubrication system

Refers to the ability of an oil to separate from water, as determined by test method ASTM D 1401 or D 2711. Demulsibility is an important consideration in lubricant maintenance in many circulating lubrication systems. Refer to Demulsifier and Dynamic Demulsibility. 

Foam Inhibitors. Methyl sihcone polymers of 300-1000 mm /s(= cSt)) at 40°C are effective additives at only 3—150 ppm for defoaming oils in internal combustion engines, turbines, gears, and aircraft appHcations. Without these additives, severe churning and mixing of oil with air may sometimes cause foam to overflow from the lubrication system or interfere with normal oil circulation. Because sihcone oil is not completely soluble in oil, it forms a dispersion of minute droplets of low surface tension that aid in breaking foam bubbles. 

The frame lubrication system circulates oil to the frame bearings, connecting rod bearings, crosshead shoes, and can also supply oil to the packing and cylinder lubrication system. Splash lubrication systems are... 

In a forced-feed lubrication system, a pump circulates lubricating oil through a cooler and filter to a distribution system that directs the oil to all the bearings and crosshead shoes. Figure 11-23 is a schematic of a typical system. The details of any one system will vary greatly. Major components and considerations of a forced feed lubrication system are as follows ... 

In positive lubrication systems, a gear-type pump is normally used to provide positive circulation of clean oil within the compressor. In some cases, the main compressor shaft directly drives this pump. In others, a separate motor-driven pump is used. 

The operation and maintenance manual shall describe how the lubrication system circulates oil. 

To fulfill the task of cooling lubrication safely, all elements of the cooling lubrication system, i.e., cooling lubricant, circulation system with feeding and cleaning devices, must be effectively designed and coordinated. 

The coolant circulators, integrated into the bottom part of the 2 reactor vessels, will be dismantled including their oil lubrication system. The circulators will be removed using existing equipment for removal, shielding and transportation. 

Nuclear Radiation Effects. Components of a nuclear reactor system that require lubrication include control-rod drives, coolant circulating pumps or compressors, motor-operated valves, and fuel handling devices, and, of course, are exposed to varying amounts of ionising (14). 

The hydraulic oil must provide adequate lubrication in the diverse operating conditions associated with the components of the various systems. It must function over an extended temperature range and sometimes under boundary conditions. It will be expected to provide a long, trouble-free service life its chemical stability must therefore be high. Its wear-resisting properties must be capable of handling the high loads in hydraulic pumps. Additionally, the oil must protect metal surfaces from corrosion and it must both resist emulsification and rapidly release entrained air that, on circulation, would produce foam. 

The centrifugal separation of solid impurities is adopted either as an alternative to filtration or combined with it. For example, having fixed-element filters that arrest larger particles, and a centrifuge system that removes the finer solids in suspension together with any water contained in the oil can clean a lubricant circulating system. 

Antifoam agents Prevent foam formation. Foaming of lubricants is detrimental for two reasons. First, in an oil-circulation system foaming may lead to a break-down of the lubrication transport. Second, the increased surface area in a foam accelerates oxidation. 

R O—rust- and-oxidation inhibited. A term applied to highly refined industrial lubricating oils formulated for long service in circulating systems, compressors, hydraulic systems, bearing housing, gear cases, etc. The finest R O oils are often referred to as turbine... 

Oil as a Lubricant Oils are used for lubrication and heat dissipation therefore, oils are circulated through a machine (through bearings, seals, or gears), returned to a tank where dirt and water are allowed to settle out, and then pumped through coolers and filters back into the machine. Without a continuous Flow of oil, machines could rapidly fail this is why backup pumps are always provided. In systems where the main oil pump is directly driven by the machine (such as in gear boxes), two backup pumps are provided one driven by an ac motor, which is the same size as the main one, and one driven by a dc motor (battery operated), which is small, since machines are always shut down if the main and the spare pumps fail. The dc-driven pump must only supply oil during the coast-down operation. 

Air may not immediately be thought of as a contaminant, but the presence of air in its various forms may have an impact on the ability of the lubricant to perform its design function. Almost all lubricating oil systems contain some air. Air is found in four phases free air, dissolved air, entrained air, and foam. Free air is trapped in a system, such as an air pocket in a hydraulic line, and may have minimal contact with the fluid. It can be a contributing factor to other air problems when lines are not bled properly during equipment startup and free air is drawn into circulating oils. 

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