2 replies to this topic

what is slope in piping? in P&ID slope 1: 100 what does it mean? can anyone explain in detail.

[gegio1960]

slope in piping is provided to avoid accumulation of liquid in the line.
the application of slope will force the liquid to go to the next low point of the line (it could be a piece of equipment).
slope could be either upstream or downstream.
slope 1:100 means that every 100 m of horizontal length, the line will be sloped by 1 m.
the most typical application of slope is relevant to the PSV inlet and outlet lines.
- inlet line is sloped upstream to the vessel
- outlet line is sloped downstream to the flare header
so the PSV will be in the high point of the line and no liquid accumulation will built-up in the in/out lines.
of course, sloped lines won't have pockets.
usual value for slope is 2:1000.

[kkala]

Thanks for the clear info on line sloping. Local Process Dept writes "slope - no pockets" on the relevant PID line, while Piping Dept specifies value of slope, depending on service. For hydrocarbon vapor PSV lines a slope of 2:1000 is applied here too, as described in post no 2.
Above concerns vapor lines, where liquids (by entrainment or condensation) are undesirable. Besides Chemical Engineers deal rather seldom with open channel flow in pipes (*), which have to be sloped; for instance see http://www.eng-tips.com/viewthread.cfm?qid=137668.
(*) where liquid flows with a free surface contacting atmospheric air.

Edited by kkala, 20 January 2013 - 07:00 AM.