Runout mechanical

Seal Chamber Runout. Mechanical seal performance is highly dependent on die runout conditions that exist at die mechanical seal chamber. Pump shall be designed for compliance widi die runout limits shown below. On smaller sizes, die actual measurement of these runout values may not be possible or practical on an assembled pump. Types of runout having significant effect on seal performance include ... 

Vectorial subtraction of slow-roll (300-600 rpm) total electrical and mechanical runout is permitted by the API rules. Vectorial subtraction of bearing-housing motion may be Justified if it can be demonstrated to be of significance. 

Optical or laser alignment systems are based on the same principles as the reverse-dial method, but replace the mechanical components such as runout gages and cantilevered mounting arms with an optical device such as a laser. As with the reverse-dial method, offset is measured and angularity is calculated. 

Optical-alignment systems offer several advantages. Because laser fixtures eliminate the mechanical linkage and runout gages, there is no fixture sag. This greatly increases the accuracy and repeatability of the data obtained using this method. 

Electrical and mechanical runout of the rotor surfaces to be observed by vibration probes shall be determined and recorded. The runout shall be determined by rolling the rotor supported by V-blocks positioned at the centerhne of the bearing journals while measuring runout with a noncontacting vibration probe and a dial indieator simultane-... 

When noncontacting vibration probes are furnished, accurate records of electrical and mechanical runout for the full 360 degrees at each probe location shall be included in the mechanical test report. 

Mechanical seal performance depends on the runout conditions at the mechanical seal chamber. Seal chamber face runout is a measure of the perpendicularity of this face to the pump shaft axis. This runout (TTR) shall not exceed 10 pm per 20 mm (0.0005 in./in.) of seal chamber bore (Appendix K). 

If the vendor can demonstrate that there is electrical or mechanical runout of the rotor surfaees at the proximity probes (see 2.5.9), a maximum of 25 pereent of the measured value or 6 microns (0.25 mils), whichever is greater, may be vectorially subtracted from the vibration signal measured during the shop test. 

Rotor mechanical and electrical runout for pumps designed to use noncontacting vibration probes. 

Provisions shall be made to centre the seal gland and/or chamber with either an inside or outside diameter register fit. The register fit surface shall be concentric to the shaft and shall have a total indicated runout of not more than 125 pm (0,005 in). Using the seal gland bolts to centre mechanical seal components is not acceptable (see Annex K). 

The bearing runout problems discussed above highlight the importance of mechanical construction in rheometers. Clearly a small departure from 90° between the axis of a small angle cone and the surface of its plate will cause the shear rate to be higher on one side than on the other. The same is true for eccentricity in the axes of concentric cylinders (eq. 5.3.43) but with typical gap sizes (> 0.5 mm), alignment is less critical than with the cone and plate. 

The rest of the test procedure in furnace testing was identical to that of the burner rig testing. The same stress ratio and cyclic frequency (R = 0.05 and 1 Hz) were used. Peak stress was varied with each test such that the correlation between the applied peak stress and corresponding number of cycles at failure could be established. The test runout condition was again set at 90,000, or 25 hours, and a specimen that survived this duration was tested for residual strength at room temperature. Microscopic study of fracture surface was carried out to document the damage and failure mechanisms as well as to determine the extent of oxidation. 

Piston rod runout and crosshead design. A imique procedure is used by this manufacturer to verify the piston rod alignment of horizontal compressors and to reduce the rod runout to a minimtun. The system allows the rod nmout to be minimized by adjusting the piston rod in relation to the piston by means of a patented eccentric device for the connection of piston and piston rod. It does not need any dismantling of the driving mechanism. This solution is superior to the method recommended in API 618, which advocates crossheads incorporating shimmed shoes. See Fig. C-71. 

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