ISO TR 21784:2018 pdf free

ISO TR 21784:2018 pdf free.Plain bearings一Spray nozzle type directed lubrication for tilting pad bearings
There are two kinds of lubrication systems for tilting pad thrust bearings: a flooded lubrication system and a directed lubrication system. In the flooded lubrication system, lubricant continually fills the inside of the bearing housing. In the spray nozzle type directed lubrication system, lubricant is sprayed from mounted nozzles between the pads to the pad surfaces (refer to Figures 3 and 4). Lubricant is supplied through the oil groove on the back surface of the bearing, led to the nozzles, and then sprayed directly to the thrust collar from the oil supply holes of the nozzles (refer to Figure 4). The nozzles can also act as pad stops, preventing circumferential movement due to rotation of the collar and retaining the pads during assembly and disassembly. The oil sprayed from the oil supply holes ensures ample fresh cooled oil is supplied to the leading edge of each pad and reduces the amount of hot oil carry over from the trailing edge of each preceding pad. The spray nozzle type directed lubrication system delivers the oil required for oil film formation directly to the thrust collar surface and eliminates the need to maintain unnecessary oil in the bearing housing.
Like tilting pad thrust bearings, tilting pad journal bearings can also be of the flooded or directed lubrication type. In the flooded lubrication system, oil fills the bearing housing and the working components are kept submerged by attaching seal rings at both axial ends of the bearing. In the spray nozzle type directed lubrication system, oil is supplied directly to the shaft surface from nozzles mounted between the pads and the seal rings attached at both ends of the bearing are removed to allow the oil to discharge freely in the axial direction. Figures 5 a) and 5 b) are examples of arrangements.
In some applications using nozzle type directed lubrication, seal rings are included, but they have a larger clearance with the shaft than in the case of those used for flooded lubrication. In this case, some oil remains to some extent in the bearing housing. Figure 5 c} shows this type of arrangement.ISO TR 21784 pdf download.