Skip to main content

Posts

Showing posts with the label power plant maintenance

Clear steps for Boiler Safety valves major overhauling

 Boiler Safety valve major overhauling steps Cleaning of safety valve Complete dismantling of safety valve. Cleaning, polishing & buffing of parts. Thorough inspection of all parts. Seat & disc lapping Spindle run out (bend) checking Spring checking for any abnormalities like crack, bend, reduced tension etc Lapping of both disc & seat. Inspection of upper & lower ring teeth for damage/crac Measurement & re-assembly. Inspection of discharge pipe connection. If there is telescopic discharge pipe, then ensure a gap of minimum 10 mm for thermal expansion. ASSEMBLY STEPS. 1-After seat & disc lapping, place lower nozzle ring on seat & level both the faces 2-After leveling, turn the lower ring by 3 notches in clockwise direction. For example if Safety valve’s operating pressure is 117 kg/cm2, then 117 kg/cm2/42.4 kg/cm2 = 2.75 Appx. 3 Nos i.e 42.4 kg/cm2 for every notch (For more details, refer manufacturing data)   Then lock the lo

Turbine oil and transformer oil standard testing parameters

  TURBINE OIL STANDARD PARAMETERS OIL: Servo prime 46T Testing frequency: Every 6 months Sl No. Oil Property UOM Test Method Acceptable limits 1 Appearance NA Visual Clear/yellow Viscous liquid 2 Colour Hazen ASTM D1500 < 2 3 Density Kg/m3 IS 1448-P-16:1990 820-870 4 Flash Point 0 C ATM D 93 > 180 5 Kinematic Viscosity at 40 0 C Cst ATM D 445-17a 43-48 6 Kinematic Viscosity at 100 0 C Cst ATM D 445-17a >6.7 7 Viscosity index NA ASTM D 2270 > 98 8 PRPVOT (Revolving Presure Vessel Oxidation  Stabilty Test)

Power plant maintenance calculations

  1-A V pulley & Belt system is used for fuel feeding system. One of the pulley of size 6” is mounted on motor shaft & other 8” on gear box shaft. Then calculate the input speed to gear box if motor rated speed is 1450 RPM is transmitted through V belt to 8” pulley. We have, Speed of motor N1 = 1450 RPM Size of drive pulley (fitted on motor shaft) D1 = 6” Size of Non end drive pulley (fitted on Gear box input shaft) D2 = 8” Speed of pulley fitted on Gear box shaft N2 =? We have the formula for calculating the speed of non-drive end side N1 / N2 = D2 /D1 N2 = N1 X D1 / D2 N2 = 1450 X 6 / 8 N2 = 1087.5 RPM Speed of Non end drive end pulley N2 = 1087.5 RPM Note: If drive end pulley is smaller than non-end drive pulley, then non end drive pulley speed is always more than drive end pulley & Vice Versa 2-A gear box input & output speeds are 1475 RPM & 100 RPM respectively, then calculate the gear box reduction ratio We have, Gear box input s