GRAVITY CONTROL TOWER (GCT) IS AN INNOVATIVE TECHNIQUE/ ARRANGEMENT FOR AUTOMATED FLOW CONTROL amp; REGULATION AT OFFTAKES EMANATING ALONG LONG GRAVITY TRUNKMAINS

摘要

Gravity Control Tower (GCT) is an innovative technique / apparatus for Automated Flow Control & Regulation along Long Gravity / Pumping Trunkmains in complex branched pipeline networks with several enroute Offtakes branching out to feed dependant Elevated Service Reservoirs (ESRs), clear water reservoirs (CWRs) etc. The principle object of this invention is to control the design HGL from drawdowns, by providing gravity control towers (GCT) to physically support HGL and prevent it from dipping / dropping down beyond the permissible design limits of drawdowns which can be sustained by the pipeline network, already anticipated during hydraulic designing of network. The distinct differences between GCT and other flow control valves is that GCT is an apparatus / method of controlling the HGL by raising the main pipeline upwards, upto, just below the operating design HGL level and then controlling flows by the permissible drawdowns within the Pressure Chamber, with a pair of air valves on its top (air valves are always to be provided at the highest points in pipeline and GCT creates these artificial peak / ridges), to which the inlet & outlet main pipelines as well as the Offtake pipeline(s) are attached and all the control operation is done automatically by virtue of behavior of drop in HGL, as it occurs due to Overdrawl, by offending Offtakes or by any leakages in pipeline. Once the GCT designed for any Offtake / location is erected, this mechanism does not require any specialized flow control valves, no valve actuators, no power supply, no man power, zero maintenance as there are no moving parts (except air valves installed on GCT peak). The series of GCTs function in segmenting the entire pipeline into manageable smaller sections, each section GCT controls its dependent Offtake overdrawls without allowing it to affect the upstream as well as downstream sections of pipeline network. This segmenting also reduces the occurrences of surge hammer as HGL is prevented from dropping below the bed level of Pressure Chamber in the upstream side of GCT, thus GCT functions as segmenting the effect of surge between two consecutive GCTs instead of the entire pipeline network. The Flow control valves on the other hand, causes surge hammer effect at shut-offs.