Why sealing required !<br />Key component of the pump is its mechanical seal. This spring loaded component consists of two faces, one stationary and another rotating, and is located on the Pump shaft between the impeller and the rear casing (see figure below). It is designed to prevent fluid from seeping outside of pump casing towards motor. Pumps designed for work in harsh environments require a seal that is more abrasion resistant than pumps designed for regular use.<br />
Mechanical Seal Vs Gland Packings<br />Loss of Material<br /> A basic comparison with the leakage rate for the compression packings and mechanical seal yields the followings:<br /> (25 drop/minx60x24)+45 drops/day=800<br /> a leakage ratio of packings to seals of 800:1<br />Power saving: 50% Less power consumption in Mechanical seal.<br />
Need of API Flushing Plan<br />To lubricate and cool the pumps mechanical seal.<br />To remove foreign particles to minimize abrasion.<br />To remove carbon deposition on compression unit.<br />To dilute ingresses material between Seal faces.<br />It could provide safety to the seal from dry running to the some extent.<br />To maintain the operational parameters of mechanical seal for which it is designed.<br />
PLANT 11<br />Plan 11. A line is connected from the discharge side of the pump and recirculated through an orifice into the gland flush connection. Orifices are hard to size and since many pumping fluids contain solids orifices are easy to clog<br />
PLAN 62<br /><ul><li>The quench gland. Often called the API gland
To dilute any leakage that might migrate across the seal faces.
To introduce low-pressure steam behind the seal to put out a fire.
The Quench connection is labeled (Q). A close fitting bushing (DB) in the end of the gland directs the quench fluid down a drain hole on the opposite side of the seal gland
Steam is the most popular quench medium, but care should be taken that the steam pressure is very low, or the hot steam will penetrate through the nearby bearing seals and contaminate the bearing oil. </li></li></ul><li>API PLAN 32<br />
Operational and Maintenance Errors<br />Operation error is the single most cause in seal failure in throughout industry today. Some are mentioned below :<br />Dry running.<br />Suction chocking.<br />Foreign material.<br />Material Incompatibility.<br />Abnormal process parameters.<br />Flushing Plan Off.<br />Maintenance fitting errors are also affects the mechanical seal Life :<br />Misalignment < 0.02 mm<br />Stuffing Box Concentricity or gland register <0.1 MM<br />Shaft Run Out < 0.07 MM<br />Stuffing Box To shaft Perpendicularity < 0.07 MM<br />End Play (Hold b/w 0.02 MM – 0.1 MM)<br />Radial Deflection < 0.07 MM <br />Failed Bearings<br />Unavailability of Flushing Plan Required<br />
Stuffing Box Concentricity or gland register <0.1 MM<br />
Stuffing Box To shaft Perpendicularity < 0.07 MM<br />