API STD 611:2008 pdf download

API STD 611:2008 pdf download.General-purpose Steam Turbines for Petroleum, Chemical, and Gas Industry Services.
Al any speed greater than the maximum continuous speed, up to and including the trip speed of the dnver, the vibration shall not exceed 150 % or 0.5 mu above the maximum value recorded at the maximum continuous speed, which ever is greater.
NOTE These Imits are not to be confused with the limits specified wi Appendix B for shop veflflcathon of unbalanced response.
6.9.4.7 II non-contacting probes or provisions for them have been specified, electrical and mechanical runout shall be determined and recorded by rolling the rotor in V blocks at the journal centerline while measuring ruriout with a non-contacting vibration probe and a dial indicator at the centerline of the probe location and one probe-tip diameter to either side.
The mechanical test report shall Include the mechanical and electrical runoul for 360 degrees of rotation at each probe location
6.9.4.8 lIthe vendor can demonstrate that electrical or mechanical runout Is present, a maxwnum of 25 % of the test level calculated from Equation 2 pim or 6 tim (0,25 md), whichever is greater, may be vectoflally subtracted from the vibration signal measured during the factory test.
6.9.4.9 II non-contacting vibration probes are not provided or If vibration cannot be measured on the shaft, the peak vibration velocity measured on the bearing housing while it operates at speeds described in 6.9.4.6 shall not exceed 3.0 mmls (0.12 mis) (unfiltered) and 2.0 mmls (0.08 mis) at running speed frequency (filtered).
6.10 Bearings and Housings
6.10.1 Bearlngs—G.n.ral
6.10.1.1 Beanngs shall be one of the following arrangements: rolling element radial and thrust, hydrodynamic radial and rolling element thrust or hydrodynamic radial and thrust. Each shaft shall be supported by two radial bearings and one double acting axial (thrust) beaflng which may or may not be combined with one of the radial bearings. Unless otherwise specified, the bearing type and arrangement shall be selected in accordance with the limitations in Table 3.
6.10.1.2 Horizontal turbines shall be equipped with thrust bearings designed to handle axial loads in either direction. Multi-stage turbines shall have hydrodynamic thrust beanngs If specified, or where ant,fnctlon bearings fall to meet the mmimum 110 rating life (See Table 3, Item b).
6.10.1.3 Vertical turbines can have oil or grease lubricated ball or roller type radial and ttwust bearwigs. Thrust bearings shall be sized for continuous operation under all specified conditions of the driven-equipment. The thrust load of the driven equipment (up andlor dowo) shall be specified on the datasheets. Rolling element bearings shall be protected against over-greasing by means of an adequately sized vent.
6.10.1.4 Hydrodynamic radial bearings shall be split for ease of assembly, precision bored, and of the sleeve or pad type, with steel-backed, babbitted replaceable liners, pads, or shells. These bearings shall be equipped with antirotatlon pins and shall be positively secured in the axial direction.
6.10.3.2 Hydrodynamlc Thrust Bearings
6.10.3.2.1 Thrust bearings shall be of the steel backed, babbitted multiple segment type, designed for equal thrust capacity in both dWections and arranged for continuous pressunzed lubrication to each side. Both sides shall be of the tilting pad type, incorporating a self-leveling feature that ensures that each pad carries an equal share of the thrust load with minor variation in pad thickness
6.10.3.2.2 Each pad shall be designed and manufactured with the dimensional precision (thickness variation) that will allow the interchange or replacement of individual pads.
6.10.3.2.3 Integral thrust collars are preferred for hydrodynamic thrust bearwigs. If integral colars are furnished, they shall be provided with at least 3 mm (1/8 in.) of additional stock to enable refinishing if the collar is damaged If replaceable collars are furnished (for assembly and maintenance purposes), they shall be positively locked to the shaft to prevent fretting
6.10.3.2.4 Both faces of thrust collars for hydrodyriamic thrust bearings shall have a surface finish of 0.4 microns (16 pin.) Ra, or better and after mounting the axial total indicated runout of either face shall not exceed 13 pm (0.0005 in.).