4. DESCRIPTION
FIELD OF THE INVENTION
The invention relates to a fluid supply flow & pressure control method and apparatus and in
particular to such a method and apparatus for a use in long water supply system. The term fluid includes all Newtonian incompressible liquids including water.
PRIOR ART& PROBLEMS to be SOL VED
As per conventional long distance water supply schemes around the world, pipeline network &
Offtakes (drawl points) are laid below / above ground level. The flow and pressure control of long gravity / rising mains with enroute Offtakes capable of achieving design flows at requisite pressures is a fairly complex operation. The adequate pressure & flows and its pipeline infrastructure vary from place to place & thus are to be hydraulically designed for every network. Conventionally, the water pipeline network is designed in such a way that, minimum requisite design pressure is maintained at all nodes / points /junctions in the system. DRAWBACKS
Any Leakages as well as enroute over drawls in the long gravity / rising pipelines are not easy to detect / regulate and any intentional / unintentional excess flow affects the entire pipeline system.
SOLUTIONS A VAILABLE in PRIOR ART
Presently the above referred problems can be controlled with the help of Flow Control Valves, Pressure sustaining valves, pressure reducing valves, along with valve accessories (Electric, pneumatic or Hydraulic valves actuators.
The present invention of Gravity Control Tower (GCT), aims to combat these problems, inherent in flow control valves by providing Economical & maintenance free Solution for the aforesaid shortcomings in the prior art.
As far as results of search in the internet, this method & apparatus adopted in GCT, has no equivalent prior art history in the field of pipeline network.
GCT functions by trapping & regulating the problem of Hydraulic Grade Line (HGL => is the line formed by joining the manometer water level readings, where manometer, is a vertical glass tube, of sufficient height, with top end free & open to air, bottom end attached to pipeline at any location along the pipeline alignment where piezometric readings, indicate the pressure in the pipeline at that location, and thus pressure is normally expressed in terms of water column height), control by reaching to water column height and developing a method & apparatus to regulate HGL as was designed to operate (when the pipeline network diameters were finalized in the hydraulic designs), within its acceptable / permissible drawdown limits,
The techniques available for the above referred regulations as Prior art, are designed to control
the HGL, from ground level, with the help of highly specialized, expensive, complex Flow Control
Valves with actuators, power supply, and manpower as prerequisites. Despite all these sophisticated
equipment, the system is prone to wear & tear resulting in costly purchases, installation, operation &
maintenance
OBJECT OF INVENTION
In case of Gravity based pipe system (Figure-1), the tail enders' (residing at lower altitudes), over drawls result in upstream system failures as sufficient pressures cannot be maintained there.
The scenario is reversed in case of Pumping based pipe system (Figure-2), here the residents of upstream section, are main beneficiaries, over drawl in upstream side results in pressure drops & less water availability to the tail enders, hence the chronic complaint, that, there is no water available at the tail ends, This is a living reality with seemingly no possible solution.
The principle object of this invention is to control the above referred drawbacks like Problem-1.
Sustaining normal / design HGL (18) to maintain flows with requisite pressure & discharge in the entire pipeline network is left to fate on the assumption that all the enroute dependent Offtakes shall draw only the design discharges. Another object of this invention is to control the following Problem-2.
The problem of leakages, pilferages or intentional tampering at any location e.g. such as at point (20) in figure-3, results in HGL drop (21) in the entire upstream section, consequently, the pipeline network is not able to maintain design pressures & thereby reduction in design discharges in case of leakage (at point 20). This also results into water hammer effect (surge) which has detrimental effects on the entire pipeline network. A further object of this invention is to control the following Problem-3.
The problem of intentional over drawl at any enroute Offtake location e.g. such as at point (8) in figure-3, results in HGL drop (22) in the upstream section (6-7-2-8), consequently, the pipeline network is not able to maintain design pressures & thereby reduction in design discharges in upstream sections and no discharge in downstream section (8-3-4-9-20-10) when HGL drawdown reaches the peak / ridge (3). HGL drop (22) will be as depicted when all the flow is withdrawn at Offtake (8), as if the pipe has burst at this point (8).
These chronic problems of Water supply department / works in particular, has been addressed by proposing an innovative technique of Gravity Control Towers (GCT)
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 with the help of 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. ADVANTAGES OF GCT
The advantages of introducing a series of GCTs in the gravity trunk pipe line are as under:-Each GCT performs the vital role
1. In case of any leakages /over drawl / pilferages or damage to pipeline causes sudden drawl of water between the two affected GCTs, the failure will be restricted to that segment only while maintaining un-interrupted supply of water in GCTs, upstream of gravity pipeline network. This arrangement is helpful in leakage detection to be carried out between the affected sections as the segmental failure is direct indicator for restoration activities instead of groping aimlessly along the entire gravity trunk main system (as usually is the case presently).
2. Series of GCTs perform the role of intermediate support towers / piers keeping HGL as per
permissible design limits & within segments formed by series of GCTs.
3. Series of GCTs perform the role of intermediate support towers /piers keeping surge hammer effect within segments formed by series of GCTs.
4. Over drawl on the upstream side as well as downstream is permitted within the hydraulic design limits, beyond that limit, the offending Offtakes' downstream section is automatically isolated without affecting the other dependent gravity Trunkmain system.
STATEMENT OF INVENTION
Accordingly, the invention of Gravity Control Tower (GCT), is an apparatus consisting of the upstream pipeline main is bent vertically upwards upto GCT level (bed level of Pressure Chamber), connects to inlet pipeline, enters a metallic pressure chamber and then outlet pipeline exits at same level, it goes vertically down and connects to downstream pipeline main at ground level. Local Offtake outlet(s) are permitted only from Pressure Chambers above the top of inlet outlet pipeline mains level. The GCT Levels are explained in Figure-10. The branching off-take outlets is always kept above top of gravity trunk main so that in case of over drawl the branched off-take fails without affecting the downstream side of gravity trunk main, On top of Pressure Chamber, air valves are provided for release of any air trapped at top under design HGL, and, act as permit air entry when HGL drawdown occurs either due to overdrawl or due to leakages downstream, successfully breaking any symphonic conditions that may develop during HGL drawdowns.
There is also provided, a method of controlling HGL drawdowns in pipeline networks to regulate flows & pressures and preventing Overdrawl by any offending enroute Offtakes, as well as restricting failures due to leakages upto the nearest upstream GCT, allowing upstream pipeline network to operate normally, helping in sectionalizing failures & identification of leakage zone. There are at least five variations of GCTs This graphic depicts enlarged views of GCTs (33, 34, 35 & 36).
1. The GCT type 33 is deployed whenever there is only one single Offtake pipeline is needed at any location, in any pipeline network.
2. The GCT type 34 is deployed whenever there are more than one Offtake pipelines are needed at any location, in any pipeline network.
3. The GCT type 33 is deployed when the main pipeline terminates and branches into more than one terminating branches, at any location, in any pipeline network.
4. The GCT type 36 is deployed whenever there is no Offtake pipeline needed at any location, in any pipeline network, but the availability of any peak / ridge can be easily utilized to better segmenting & control of HGL. In case of pumping based pipeline networks, the GCT (36) can easily be adopted just outside of the pumping station as this would convert the
Page 5 of 17

long rising main into a very small vertical rising main / penstock & beyond this GCT, the flow would be like gravity flow conditions. 5. GCT cum ESR version (refer Figure 12) is a special combination of merging the benefits of GCT where local ESR is to be constructed. DETAILED DESCRIPTION OF INVENTION (WITH REFERENCE TO DRAWINGS / FIGURES).
(Table Removed)
1. FIGURE-1.1 Depicts
Plan of typical landscape with pipeline network including Source CWR (6), Gravity Trunkmain (alignment 6-7-8-9-10), Offtakes (7, 8, 9 & 12), branched pipeline (7-11, 8-15, 8-12, 12-13, 12-14, 9-16 & 9-17), ESRs (11, 13, 14, 15, 16 & 17) & terminal CWR (10)
2. FIGURE-1.2 Depicts
Longitudinal section along the pipeline network including Source CWR (6), Gravity Trunkmains (6-7-8-9-10), Offtakes (7, 8 & 9), terminal CWR (10) & its HGL (18).
HGL is Hydraulic Grade Line in simplest terms; it can be understood by the study of any irrigation contour canal system. Hydraulic grade line (HGL is the line formed when water surface is in contact with atmosphere) which implies, that HGL line is always at atmospheric pressure. Thus the contour canals are designed keeping HGL as canal's full supply level (FSL), and depth of canal is adopted to decide the canal's bed level which normally rests on firm natural ground.
To achieve this condition, the terrain for contour canal construction has to be of gently falling gradient & favorable. But this is not always feasible, and then use of pipeline along the available ground profile is adopted, allowing the water to flow under higher pressures. This is known as pipeline system under gravity flow and the imaginary line (Piezometric line) above the pipe centerline where the pressure reduces upto atmospheric pressure is the hydraulic grade line (HGL). which in turn, is the deciding parameter for maintaining the design flow discharges at requisite pressures for any pipeline network to function properly, we aim to control this imaginary line (HGL) with the help of this GCT invention.
3. FIGURE-2.1 Depicts
Plan of typical landscape with pipeline network including Source CWR (6), Pump sets (19). Pumping Trunkmain (alignment 6-19-7-8-9-10), Offtakes (7, 8, 9 & 12), branched pipeline (7-11, 8-15,8-12, 12-13, 12-14, 9-16 & 9-17), ESRs(l 1, 13, 14, 15, 16& 17) & terminal CWR (10).
4. FIGURE-2.2 Depicts
Longitudinal section along the pipeline network including Source CWR (6), Pump set (19), Pumping Trunkmains (6-19-7-8-9-10), Offtakes (7, 8 & 9), terminal CWR (10) & its HGL (Hydraulic Grade Line => 18).
5. FIGURE-3.1 Depicts
Same as figure 1.1 above for study of problems being encountered in pipeline network due to leakages & due to over drawl.
6. FIGURE-3.2 Depicts
Longitudinal section along the pipeline network including Source CWR (6), Gravity Trunkmains (6-7-8-9-10), Offtakes (7, 8 & 9), terminal CWR (10), This graphic depicts the various possible flow failures in pipeline system
a) Problem-1
Sustaining normal / design HGL (18) for maintaining flow with requisite pressure & discharge in the entire pipeline network is left to fate on the assumption that all the enroute dependent Offtakes shall draw only the design discharges.
b) Problem-2
The problem of leakages or intentional tampering at any location e.g. such as at point (20) in
figure-3, results in HGL drop (21) in the entire upstream section as pipeline network is not able to maintain design pressures & thereby reduction in design discharges in case of leakage (at point 20). c) Problem-3 The problem of intentional over drawl at any Offtake location e.g. such as at point (8) in figure-3.2, results in HGL drop (22) in the upstream section (6-7-2-8), as pipeline network is not able to maintain design pressures & thereby reduction in design discharges in upstream sections and no discharge in downstream section (8-3-4-9-20-10) when HGL drawdown reaches the peak / ridge (3). HGL drop (22) will be as depicted when all the flow is withdrawn at Offtake (8), as if the pipe has burst at this point (8).
7. FIGURE-4.1 Depicts
Search of similar real life problems. Plan of typical landscape starting point(l), alignment under study (1-2-3-4-5), dips (2 & 4). ridges (1, 3 & 5). Same as figure 1.1 above without pipeline network.
8. FIGURE-4.2 Depicts
Longitudinal section along the typical alignment This graphic depicts one long and thick single deck bridge (24) to span the entire length (from 1 to 5), resting on two abutments (23) at the ends.
Although it is possible if the length is small, but the proposal becomes uneconomical as the span increases, the slab thickness has to be increased to control excessive deflection in the slab.
We can develop an analogy between pipeline and single deck bridge slab
1. The length of pipeline = length of bridge
2. The HGL in pipeline = deflection in slab of single deck bridge.
9. FIGURE-5.1 Depicts
The problem proposed in figure- 4.2 can be easily solved by introducing several intermediate piers (26) thus restricting the large deflection of Single deck bridge in smaller multiple panels simply supported at end abutment (25) & piers (26) & between piers (26-26). Thus the problem of thicker slabs to arrest larger deflection in single deck bridges has been successfully solved by introducing intermediate vertical supports. The world is full of multi-decked, multi-pier bridges.
10. FIGURE-5.2 Depicts
The problem of carrying overhead High Tension Power transmission line (29) can be easily solved by introducing several evenly spaced, intermediate towers (28) thus restricting the large catenary's sag, without introduction of towers(28), these HT cables would touch the ground due to its self weight and electricity can be hazardous to mankind. Thus the problem of HT Power
transmission line has been successfully solved by introducing intermediate vertical support towers.
11. FIGURE-5.3 Depicts
The problem of ascending high mountains is being successfully done by erecting Ropeways (32) on several intermediate towers (30) thus restricting the large catenary's sag / dip. Thus the cable cars (31) hanging from the ropeway (32) overhead on towers (31) has been successfully implemented for transportation of tourists, goods etc in the hilly mountainous terrain.
12. FIGURE-6.1 Depicts
Same as figure 1.1 above for study of problems being encountered in pipeline network due to leakages & due to over drawl and solutions by introducing gravity control towers (GCT) of various types (33. 34. 36 & 36)
13. FIGURE-6.2 Depicts
Longitudinal section along the pipeline network including Source CWR (6), Gravity Trunkmains (6-7-8-9-10), Offtakes (7, 8 & 9). and terminal CWR (10), with location of Gravity Control Towers (33, 34 & 36) to support the HGL in the gravity Trunkmain (the GCT (type 35) installed on the branch (8-12) supports the HGL in this branch (8-12) similarly).
14. F1GURE-7.1 Depicts
Same as figure 6.1 above for study of problems being encountered in pipeline network due to leakages & due to over drawl and solutions by introducing gravity control towers (GCT) of various types (33. 34. 36 & 36) Same as figure 6.1 above for study of problems being encountered in pipeline network due to leakages & due to over drawl and solutions by introducing gravity control towers (GCT) of various types (33. 34. 36 & 36)
15. FIGURE-7.2 Depicts
Longitudinal section along the pipeline network including Source CWR (6), Gravity Trunkmains (6-7-8-9-10), Offtakes (7, 8 & 9), and terminal CWR (10), with location of Gravity Control Towers (33, 34 & 36) to support the HGL in the gravity Trunkmain (the GCT (type 35) installed on the branch (8-12) supports the HGL in this branch (8-12) similarly).
The functioning of GCTs introduced in figure 6.2 above for solving the problems depicted in figure 3.2 is explained graphically as below a) Solution for Problem-1 (refer to description of Figure 3.2 above)
Solved by introducing maintenance free, power free & manpower free Gravity control towers (types 33, 34, 35 & 36) at every Offtake (7, 8 & 9), branched junction (12), Ridges (at intermediate peaks 3 & start of rising main after pump's delivery main (19) refer figure 2.2), the single continuous HGL (18) is thus segmented into smaller sections by erecting GCTs at every Offtakes, ridges, similar to restricting deflections in multi decked bridges, catenary sag / dip in ropeways &
HT transmission lines by erection of piers (26) / towers (28 & 30) (refer figure 5).
b) Solution for Problem-2 (refer to description of Figure 3.2 above)
The leakage point (20) in pipeline section (9-20-10) will affect only in supply failure in section (9-20-10) only without affecting the pipeline section (6-7-2-8-3-4-9) upstream of GCT (type 34 at Offtake (9)).
Gravity control towers (types 33, 34, 35 & 36) function as breaking the single HGL (18) in segments created due to series of vertically erected GCTs, and failure in any segment will be restricted to the downstream sections only, The readjusted HGL (39) in case of leakage is depicted in figure- 7.2
c) Solution for Problem-3 (refer to description of Figure 3.2 above)
The erection of GCT at Offtake (8) will control the over drawl in pipeline section (6-7-2-8-3-4-9-20-10) and offending Offtake point (8)) will not be able to affect the pipeline flow system at any point of time, the worst damage Offtake (8) can cause is automatic isolation and failure of its own maximum permissible discharge drawl & subsequent isolation of Offtake (8) dependent Branches, without affecting the upstream as well as its downstream flow & pressure characteristics of the remaining pipeline network.
Gravity control towers (types 33, 34, 35 & 36) function as Offending Offtake isolators before it can cause and HGL draw downs (22), the readjusted HGL (40) develops in response to attempted over drawls by offending Offtake(8). The GCTs will function properly, only if Offtakes are made as per design i.e. from top end of pressure chamber (37) on top of GCT, and no intermediate tapings are permitted in pipeline between any two consecutive GCTs 16. FIGURE-8.1 & FIGURE 8.2 Depicts
Enlarged view of GCT from Figure 7.2, representing HGL readjustments during leakages. This has been graphically depicted, the GCT (type 34 at Offtake location (8 & 9)). When HGL drop (22) occurs due to leakages it is automatically restricted upto the bottom of Pressure chamber (37), this is because of the height of Gravity Control Tower creates an artificial obstruction upto Pressure Chamber's bed from the natural ground level where GCT is erected.
The function performed by GCT is as follows. The water enters through inlet pipeline (41) flow path goes vertically upwards, enters the pressure chamber (37), stabilizes and then comes downwards from separate outlet pipeline (42) vertically downwards, connecting to the downstream main pipeline. The top of Pressure chamber (37), is fitted with a pair of kinetic air valves (38) to permit entry of air into the pressure chamber (37), thereby breaking the pressure as well as any symphonic conditions that may have built up due to drawdowns. The readjusted HGL (39) in case of leakage is depicted in figure- 7.2
The Offtakes are permitted only from the upper part of pressure chamber's side walls (the top of main inlet pipeline (41) is always below the Offtake pipelines' bottom (43, 44 and additional Offtake pipes (if any), attached to pressure chamber (37)), before it is allowed any branching Offtakes (40) as well as allowing flow to main pipeline (42) downstream, and the readjusted HGL (40) in case of offending overdrawls from any Offtake is depicted in figure- 8.
17. FIGURE-9 Depicts
This graphic depicts enlarged views of GCTs (33, 34, 35 & 36).
a) The GCT type 33 is deployed whenever there is only one single Offtake pipeline is needed at any location, in any pipeline network.
b) The GCT type 34 is deployed whenever there are more than one Offtake pipelines are needed at any location, in any pipeline network.
c) The GCT type 33 is deployed when the main pipeline terminates and branches into more than one terminating branches, at any location, in any pipeline network.
d) The GCT type 36 is deployed whenever there is no Offtake pipeline needed at any location, in any pipeline network, but the availability of any peak / ridge can be easily utilized to better segmenting & control of HGL. In case of pumping based pipeline networks, the GCT (36) can easily be adopted just outside of the pumping station as this would convert the long rising main into a very small vertical rising main / penstock & beyond this GCT, the flow would be like gravity flow conditions.
18. FIGURE-10.1 Depicts
This graphic represents the plan of a multi Offtake GCT with cut section. The upstream gravity Trunkmain pipeline (54) is bent up vertically and enters the Pressure Chamber (37) through inlet Trunkmain pipeline (41). Water inside the pressure chamber (37) is normally under design HGL (18) pressure. Outlet Trunkmain pipeline (42) is connected to downstream Gravity Trunkmain pipeline (55). The pressure chamber (37) also is fitted with a pair of kinetic air valves (38) & isolating sluice / butterfly valves (48).
19. FIGURE-10.2 Depicts
This graphic depicts the internal details of Multi port Offtakes (43, 44, & 45, three in this case), which are connected to the Pressure Chamber (37) at least, 1m above the top of Inlet pipeline (41), so that, whenever the HGL (18) is dropping down as a result of Offending Offtake (43, 44 or / and 45) over draws beyond its design permissible limit (53), the water (47) in the pressure chamber (37) goes down, Offtakes' outlets (43,44, & 45) get exposed to atmospheric pressure via the Kinetic air valves (38). This result in free flow of air, without any possible symphonic conditions, the flow in Offtakes (43, 44 &45) ceases when HGL (18) readjusts to HGL (40). This automatic isolation of
offending Offtakes while the flow continues downstream through Outlet Trunkmain (42 & 55) under Pressure (52), The downstream pipeline (55) is hydraulically designed for requisite flows taking pressures available upto bed of Pressure Chamber (37) i.e. height of GCT Pressure Chamber (37) from natural ground level (49)=(50). Thus the flows in downstream pipeline are unaffected even if the Offtakes are overdrawing.
The other possible failure pattern is that there is leakage (20) in downstream pipeline (55), the HGL (18) gets readjusted to HGL (39), The Offtakes (43, 44 & 45) and Outlet (55) fail, but the upstream Pipeline network is unaffected due to this leakage. The Offtakes are restored by simply closing the leaky pipeline (55) through its isolation sluice / butterfly valve (48).
20. FIGURE-11.1 Depicts
This graphic represents the plan of a multi Offtake GCT with cut section. The upstream gravity Trunkmain pipeline (54) is bent up vertically and enters the Pressure Chamber (37) through paired inlet(s) Trunkmain pipelines (41) in opposite directions so as to cancel out any thrusts developed due to higher pressures as the height of GCT increases. Water inside the pressure chamber (37) is normally under design HGL (18) pressure. Outlet is again through paired Trunkmain pipelines (42) in opposite directions so as to cancel out any thrusts developed due to higher pressures as the height of GCT increases, further connected to downstream Gravity Trunkmain pipeline (55). The pressure chamber (37) also is fitted with a pair of kinetic air valves (38) & isolating sluice / butterfly valves (48).
21. FIGURE-11.2 Depicts
This graphic depicts the internal details of Multi port Offtakes (43 & 44 two or more can be accommodated easily), which are connected to the Pressure Chamber (37) at least, 1m above the top of paired Inlet pipeline (41), so that, whenever the HGL (18) is dropping down as a result of Offending Offtake (43 or / and 44) over draws beyond its design permissible limit (53), the Offtakes' outlets (43 & 44) get exposed to atmospheric pressure via the Kinetic air valves (38). This result in free flow of air, without any possible symphonic conditions, the flow in Offtakes (43 & 44) ceases when HGL (18) readjusts to HGL (40). This automatic isolation of offending Offtakes while the flow continues downstream through Outlet Trunkmain (42 & 55) under Pressure (52), The downstream pipeline (55) is hydraulically designed for requisite flows taking pressures available upto bed of Pressure Chamber (37) ie height of GCT Pressure Chamber (37) from natural ground level (49)=(50). Thus the flows in downstream pipeline are unaffected even if the Offtakes are overdrawing. The GCT is embedded in the concrete thrust block (46).
22. FIGURE-12 Depicts
This graphic depicts the possible merger of GCT and ESR wherever there is an enroute Local
ESR to be constructed and HGL (18) runs on top of ESR inlet level. BEST METHOD OF WORKING
The Gravity Control Tower functioning has already been explained in detail vide figures 6 to 12 above. The critical data needed for proper functioning of any GCT at any location are
a) The GCT Height (50) from ground level).
b) Level (51) => diameters of inlet / outlet pipes (41 & 42), for HGL (39).
c) Level (52) => Height of Offtake outlet pipeline above crest of inlet / outlet Pipes (41 & 42) for HGL(40)
d) And normal operating HGL (18) in case the entire pipeline network strictly as per design hydraulics & controlled drawls.
The best method developed for this purpose is developing a Hydraulic simulation model using the public domain software "EPANet 2.00.12" developed & available at US environmental Protection Agency's website.
a) Step-1,
Develop the hydraulic model (for example as in Figure-1) in conventional way, and test it, optimize it by adjusting the most economical diameters that would permit flow in the pipeline network with desired terminal pressures at tail ends.
b) Step-2,
Focus on any single Branched Offtake in the hydraulic model (for example node (7) at ground level in Figure-1 and refer figure-10 for GCT details). Note the pressures at nodes (7 & 8) for this is normal HGL( 18)
c) Step-3,
Develop an equivalent hydraulic model for GCT-1 at node (7) by inserting two new nodes (54 and 55) to represent Upstream inlet pipeline and downstream pipeline at ground level respectively. Similarly add one node (44) to represent the inlet (44) as well as (45) to act as the bed level of Pressure Chamber (37). Add one more node to represent Offtake pipeline outlet (43). Connect inlet main pipeline (54-44), outlet main pipeline (44-55), Offtake Outlet pipeline (44-43) and branch pipeline (43-11) connecting GCT Offtake to ESR (11). Initially keep the Relative levels of all the newly created nodes same as original RL of node (7).
d) Step-4,
Increase the demand of ESR (11) by 20% (assuming that, 20% drawl can be anticipated / is expected from the pipeline network without failing) drawl, and test it, optimize it by adjusting the most economical diameters that would permit flow in the pipeline network with desired terminal pressures at tail ends. Note the pressures at node (43), the HGL (18) has dropped to a lower level,
this is readjusted HGL (40). This is the level beyond which no water should be allowed to flow
towards the overdrawing Offtake. Update the RL reading of Node (43) by adding the pressure (or
reading the Heads directly from the junction properties to be displayed in EPANet). Thus the cutoff
level has been determined for 20% permissible overdrawl.
e) Step-5,
Add one more similar GCT-2 an equivalent hydraulic model for GCT at node (8) downstream
And adjust GCT-2 nodes (44 & 43) RL to the HGL (18) level (this setting is to ensure that
downstream GCT-2 to function at normal HGL (18) despite any disturbances in the upstream GCT-
1).
To determine the GCT-1 bed level, gradually, increase the drawl at next consecutive GCT-2 downstream (this forces HGL drawdown between GCT-1 & GCT-2, but GCT-2 is forced for HGL(18) conditions, there will be drawdown of HGL at GCT-1 to lower level), till the economical pipeline (55-8) determined in Step-1 above fails to carry flow. This is the HGL below which there cannot be any flow for the diameter of pipeline (55-8). This is the Bed level of Pressure chamber or in other words, height of GCT-1.
Thus all the vital elements for fixing the levels of Height of GCT-1 / Bed of Pressure chamber, Cutoff level of overdrawing (assumed permissible limit of 20%), normal HGL have been determined. Repetition of above steps 1 to 5 for every additional GCTs and readjusting the diameters for optimization will build a hydraulic simulation model capable of trapping the Overdrawls as well as leakages within the GCTs' design behavior. Thus no other control valves of any sort are needed once the GCTs have been designed for the pipeline network using the above method.

STATEMENT OF CLAIMS I claim
1. Accordingly, the invention of the product, Gravity Control Tower (GCT), process & method consisting of upstream main pipeline (conventionally laid at natural ground level) at node, peak, branching Offtakes, is / are split into Inlet Pipeline(s) (single vertical pipeline as well as multiple paired pipelines), raised to HGL drawdowns activity zone / level, this /these inlet(s) enter a small pressure chamber (as well as vertical Tee pipeline), near the pressure chamber's bed level, and (from same level as inlet), Outlet pipeline(s) Inlet Pipeline (single vertical pipeline as well as multiple paired pipelines), is /are lowered again to natural ground level, at ground level, these outlet pipelines are rejoined to downstream main pipeline. Any branched Offtake outlet(s) are permitted at levels above the crest of main pipelines' inlet(s) / outlet(s), thus ensuring, that the Offtake outlet(s) are isolated beyond their permissible overdrawls without being detrimental to flows in the main pipeline (u/s as well as d/s). Kinetic air valves as well as air release valves / vacuum breaker valves) permit entry & exit of air in the pressure chamber & symphonic conditions are avoided.
2. The device as claimed in Claim-1, wherein one inlet or multiple paired inlet pipelines connect to pressure chamber (or vertical tee jointed pressure pipeline). The multiple paired pipeline inlets are diametrically opposite to each other, to cancel out any resultant thrusts and keep the tower structure stable. The same logic has been applied for Outlet pipelines as claimed in claim-1 above.
3. The inlet & outlet pipelines as claimed in claim-1 & further defined in claim-2, are also used as part of the structure needed to support the Pressure chamber, Offtake pipeline(s), air valves and other accessories fabricated at top, within the HGL Drawdown activity zone. These vertical pipelines can be supported by RCC frame structure as well as can be fabricated from steel similar to self supporting lattice towers for Microwave /mobile communications, the inlet & outlet pipelines are clamped / act as tubular support structures as per suitability of structure.
4. The device as claimed in Claim-1, wherein there can be single Offtake outlet pipeline when only one dependent Offtake is to be branched out at any location in the pipeline network.
5. The device as claimed in Claim-1, wherein there can be multiple Offtake outlet pipelines when more than one dependent Offtakes are to be branched out at any location in the pipeline network.
6. The device as claimed in Claim-1, wherein no Offtake outlet pipeline is installed, as no branching is needed, but only the main pipeline is looped vertically upwards through the GCT's
pressure chamber in order to support the HGL wherever any Peak / ridge / at start of rising / pumping main is encountered along the alignment in the pipeline network.
7. The device as claimed in Claim-1, wherein Elevated Service Reservoir is also to be constructed at GCT location, then, these two structures can be merged, the supporting columns & bracing beams can be designed to support the GCT within the ESR structural design.
8. The device as claimed in Claim-1, wherein, the pipelines connected to pressure chamber can be of fabricated mild steel pipeline and lattice braced framed structure of steel to support the tower loadings.
9. The device as claimed in Claim-1, wherein, the various levels are designed by the method of
hydraulic simulation modeling.
10. An invention of the product, Gravity Control Tower (GCT), process & method using the inventive concept, substantially as herein described in the specification with reference to the accompanying drawings (figures 1 to 12)