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Lubrication and Reliability Handbook 2010 Part 5

Tham khảo tài liệu 'lubrication and reliability handbook 2010 part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | A19 Circulation systems Double-line systems Double-line elements can be used in conjunction with a reversing valve and piston or gear pump to lubricate larger numbers of points spread over longer distances geographically. These elements and their operation are similar to those previously described under grease systems. Typical applications Machine tools textile plant and special-purpose machinery. Figure 19.5 Simple low-pressure systems The simple form illustrated uses a gear pump feeding the points from connections from a main feed line through needle valves with or without sight glasses. Typical applications Special-purpose machiner y and machine tools. DELIVERY LINE Figure 19.6 Gravity-feed systems Gravity-feed systems consist of a header tank piped through to one or more lubrication points. The level in the header tank is maintained by a gear or other pump with relief valve and filter mounted at the collection tank. This may be used as a back-up for a forced-feed system where important bearings have a long run-down period after removal of the power source e.g. large air fans. PUMP OVERFLOWRELIEF VALVE Figure 19.7 LINE Figure 19.8 A19.3 Circulation systems A19 GROUP 2 SYSTEMS The larger and usually more complex type of oil-circulatory system used for both lubrication and cooling falls into two distinct classes. The first type known as the self-contained system is usually limited in size by the weights of the components. For this reason the storage capacity of this type does not usually exceed 1000 gal. The second type covering the larger systems has the main components laid out at floor level e.g. in the oil cellar. The detailed design considerations of the main components are discussed elsewhere but in laying out the system the possible need for the equipment in Table 19.1 should be considered. Self-contained systems PRESSURE GAUGE REMOVABLE LID DRAIN COCK MAIN LUB. OIL CIRCULATING PUMP RETURN CONNECTIONS 2 BREATHER SHUT-OFF VALVES 2 STAND-BY .