FORM 2
THE PATENTS ACT, 1970
(39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and rule 13}
l. TITLE OF INVENTION Hydraulically operated Zero
velocity valve
2. APPLICANTS)
a. Name: l)Vikrant Karandikar
2] ShrikantBorle
b. Nationality: Indian National
c. Address: 1) Flat No 5, Lata Sadan,Plot no 15 ,
United western Housing Society, (Opp Tathawade Uddyan) Karve Nagar, Pune - 411052.
2] 311, Greenpark Society, Vsahyadri Society, Karvenagar Pune 411052.
"PREAMBLE TO THE DESCRIPTION The following specification
particularly describes the invention and the manner in which it is to be performed.

HYDRAULICALLY OPERATED ZERO VELOCITY VALVE
FIELD OF INVENTION
Present invention is related to valves used on water pipelines. More particularly the present invention is related to valves used for eliminating surge pressure when water velocity becomes zero in long pipelines due to stoppage of pumping.
PRIOR ART
Water pipelines for water supply are laid between sources where water pumping stations are provided, to high level water tanks from where water is supplied to users. The length of these pipe lines usually has to be of the order of few kilometers to many kilometers. These pipe lines are run along the profile of land on which they are laid causing high and low points in their level at different places according to the profile of the land. Due to long length of these pipelines, problems are created which are to be solved while designing and installing these pipelines.
When water pump stops due to break down or due to advertent switching off for maintenance; due to sudden stoppage of pump the forward velocity of water column goes on decreasing due to friction and gravity. The water column on upgrade reverses its velocity causing surge pressure. This surge pressure is harmful

for the pipeline. Hydraulically operated zero velocity valves are provided on such points on the pipe line. Function of Hydraulically operated zero velocity valve is to avoid the surge pressure by closing the valve gradually. A bypass is provided in the valve to maintain balanced pressure across the valve and also to avoid vacuum on the downstream side of valve if that column experiences certain reversal.
The hydraulically operated zero velocity valves according to prior art are described below with help of following figure.
Fig 1 shows cross sectional view of hydraulically operated zero velocity valve according to prior art.
With reference to Fig 1, hydraulically operated zero velocity valve; hereinafter referred to as "the valve", in the description of the prior art, comprises shell (1) which houses the components of the valve. Arrow [A] shows direction of water flow through the valve. At upstream end and downstream end of the valve, plurality of disc supporting ribs (12) is provided. An additional set of ribs (14) is provided half way between the supporting ribs (12) at upstream and downstream end of the valve. The said sets of ribs support plurality of shaft sleeves (3) and bushes (5) provided at the center line of the valve which fix the shaft (4) slidably and coaxially with the shell (1). A disc (2) is fixed on the shaft (4) coaxial with shell (1). The disc (2) is kept pressed

against an orifice (13) at the upstream side by means of plurality of springs (8) and keeps it closed thus closing the valve when water is not flowing through the pipe line. A bypass [9] is provided across the valve together with an isolation valve (10). An inspection window (6) is provided on the shell [1] for inspection of inner parts. When water starts flowing through the valve, disc (2) is pushed away from an orifice (13] against the force of springs (8) creating passage for water flow. Internal cone (7) is provided to achieve streamlined flow of water through the valve to reduce head loss through the valve. In another embodiment as an alternative to internal cone (7] a dome is provided for better streamlining of the flow of water. The springs are so designed that the disc remains in fully open position for velocity of water equal to approximately 25% of the designed maximum velocity in the pipeline.
With sudden stoppage of pump, the forward velocity of water column goes on decreasing due to friction and gravity. When forward velocity becomes less than 25% of the maximum, the disc starts closing at the same rate as the velocity of water. The disc comes to the fully closed position when forward velocity approaches Zero magnitude.
Water column on the upstream side of the valve is thus prevented from acquiring a reverse velocity and taking part in creating surge pressures. The by-pass maintains balanced pressure on the

disc and also avoids vacuum on the downstream side of valve if that column experiences certain reversal.
Limitations and drawbacks of the prior art
1. The closure of prior art valves starts only when flow velocity is reduced to about 25% of the maximum, this limits the closure time of the valve and hence valve is inefficient in reducing surge pressures.
2. In prior art valves the disc is oriented to move axially for creating flow passage, causing resistance to flow. To reduce the head loss by streamlining the flow, it is required to provide internal cone or dome; due to this, it becomes necessary to provide a bulge in the diameter of shell around the disc and internal cone or dome, increasing size of the valve requiring more space for installation.
3. In spite of the provision of internal cone or dome, the head , loss in the valve is high.
4. The control springs according to prior art valve is mounted inside the shell of the valve causing difficulty in maintenance.

OBJECTIVE AND SUMMARY OF THE INVENTION
1. The object of present invention is to provide controlled closure of valve and start the closure as soon as the flow velocity of water starts reducing, thus providing efficient surge pressure suppression.
2. Another object of the present invention is to provide clear flow passage for water, thus offering minimum resistance to flow. This reduces the head loss. This is achieved with out increasing diameter of shell.
3. Yet another object of the present invention is to provide the valves which require less space for installation.
4. Yet another object of the present invention is to obviate need of an internal cone or dome which are required in case of prior art valves.
5. Yet another objective of the present invention is to provide an externally mounted control unit facilitating ease of maintenance.
To achieve said objectives and address the limitations of the prior art valves, the present invention uses a hinged disc to stop the

water flow in the manner required, based on analysis of the pipe line.
The "hydraulically operated zero velocity valve" according to present invention comprises a tubular shell in place of bulged shell of the prior art valves. A body with orifice for allowing water flow is provided inside the shell. The said orifice is closed by a disc which is hinged near body at inner periphery of the shell and is vertically placed with respect to axis of the shell. The said disc is enabled to close and open the orifice when it turns around the hinge.
When water flow starts, the disc is lifted due to dynamic force of flowing water creating free area for flow. When the water flow stops, the disc turns under gravity due to self weight to close the valve.
The hinge which bears the disc comprises a shaft rotatably fixed in bearings. The said disc is fixed to the shaft by means of a support plate. The said disc is provided with a hole enabling balancing water pressure across the valve when valve is closed during operation.
The said shaft sealably extends out from the shell forming shaft extension. The rotary motion of the shaft and in turn the closing and opening of the valve is controlled by a control unit provided

in juxtaposition of said shaft extension. The said control unit comprises hydraulic cylinder and cylinder rod extending out from the cylinder is connected to said shaft extension by means of linkage enabling the control unit to control rotary motion of the said shaft.
In first alternate embodiment, the control unit comprises plurality of hydraulic cylinders connected in series. In second alternate embodiment, the said hydraulic cylinders are connected in parallel.
In third alternate embodiment, the internal profile of the bore of the hydraulic cylinder is varied in axial direction enabling it to provide programmable control of the rotary motion of the said shaft.
Each of the said hydraulic cylinders are provided with a control circuit which comprises a unidirectional flow control valve connected between inlet and outlet ports of the cylinder. The cylinder with its control circuit is fully filled with a hydraulic fluid. During rotary motion of the shaft while closing and opening of the valve, the linkage between the shaft and the cylinder rod moves the cylinder rod in forward and return directions respectively, thus displacing hydraulic fluid. The said unidirectional flow control valve offers free flow of hydraulic fluid when the shaft turns to open the valve enabling opening of the

valve without any resistance to flow. When the valve is closing the turning of the shaft and hence the speed of closing of valve is controlled by the flow control valve according to preset flow control. The setting of the flow control valve is decided according to analysis of the pipe line, to achieve precalculated result.
The alternative embodiments described above enable setting of the hydraulically operated zero velocity valve so as to reduce the surge pressure to a permissible value, which is decided on the basis of analysis of the pipe line.
It is evident from above description that all the objectives mentioned above addressing the prior art problems are achieved by the present invention.
STATEMENT OF THE INVENTION
Hydraulically operated zero velocity valve (the valve) for
installation on water pipe lines for reducing surge pressures
comprising
a shell for housing components of the valve;
a body fixed in side the shell coaxial with internal diameter of the
shell; said body provided with an orifice to allow flow of water
through;
a disc enabled to close and open the orifice, said disc fixed by
hinge above said orifice vertically above axis of the shell;

said disc provided with a hole enabling balancing water pressure
across the valve when valve is closed during operation;
said hinge comprising a shaft supported on bearings and having
an extension extending out of the shell in sealable manner;
said disc fixed to said shaft of the hinge by means of support
plate, thereby turning motion of the disc being imparted to said
shaft;
a control unit linked to said shaft extension enabling control of
turning motion of said shaft, thereby controlling closing and
opening of the orifice by said disc;
said control unit comprising of a composite hydraulic cylinder,
said composite hydraulic cylinder further comprising at least one
hydraulic cylinder with its control circuit; said hydraulic cylinder
with its control circuit filled with hydraulic fluid;
said control circuit comprising of bypass pipes connecting inlet
and outlet oil ports of said hydraulic cylinder through a
unidirectional flow control valve; thus providing free motion of
the said shaft in the direction in which said disc turns to open the
orifice and restricted motion of the said disc when it is closing
said orifice;
said unidirectional flow control valve being set to a preset value;
thereby, enabling free opening of the valve and closing of the
valve at a preset speed, to control surge pressure developed in
the pipe line, said preset speed being determined according to
surge analysis of the pipe line.

Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises plurality of hydraulic cylinders connected in series to form a composite cylinder. Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises plurality of hydraulic cylinders which are connected in parallel, forming a composite cylinder.
Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises plurality of hydraulic cylinders connected in series and parallel combination. Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises said hydraulic cylinder with internal profile of its bore varied in the axial direction of the cylinder, providing variable clearance at different axial positions between outer diameter of its piston and bore of the hydraulic cylinder enabling to provide programmable control of the rotary motion of said shaft.
Hydraulically operated zero velocity valve as claimed in claim 1 to claim 4 wherein said control unit comprises at least one hydraulic cylinder provided with variable clearance between piston and cylinder in axial direction of the cylinder as claimed in claim 5. Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises at least two of the plurality of hydraulic cylinders are provided with common unidirectional flow control valve with bypass pipes and the remaining hydraulic

cylinders provided with individual unidirectional flow control valve together with connecting bypass pipes.
Description of figures
Fig 1 shows cross sectional view of hydraulically operated zero velocity valve according to prior art
Fig 2 shows cross sectional view of the hydraulically operated zero velocity valve according to the present invention along its axis as installed in pipeline
Fig 3 shows side view of the hydraulically operated zero velocity valve according to the present invention
Fig 4 shows the details of linkage between the shaft and cylinder rod of the hydraulic cylinder provided in control unit, the details at "D" with reference to Fig 3, according to the present invention
Fig 5 shows the axial cross sectional view of the hydraulic cylinder according to fourth alternate embodiment of the present invention
Fig 6 shows the arrangement of plurality hydraulic cylinders in series according to the first alternate embodiment of the present invention

Fig 7 shows the arrangement of plurality of hydraulic cylinders in series according to the second alternate embodiment of the present invention
Fig 8 shows the arrangement of plurality of hydraulic cylinders in series and parallel combination according to third embodiment of the present invention
DESCRIPTION
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.
This invention, is illustrated in the accompanying drawings, throughout which, like reference letters indicate corresponding parts in the various figures.
The "hydraulically operated zero velocity valve" (100), hereinafter referred to as "the valve (100]"; according to present invention comprises a tubular shell (101) in place of bulged shell of the prior art valves. The valve (100) is installed in pipeline as shown in ghost lines in Fig 2 by means of flanges (113) and fasteners (not shown) provided at both ends of the valve (100). A

body (103) with orifice (14) for allowing water flow is provided in side the shell (101). The said orifice (14) is closed by a disc (102) which is hinged near body (103) at inner periphery of the shell (101) by means of a hinge (15) which is vertically placed with respect to axis of the shell (101) in working position of the valve (100) as installed on the pipe line. The said disc (102) is enabled to close and open the orifice (14) when it turns about the hinge (15).
Water flow direction through the valve (100) is indicated by an arrow (A). When water flow starts, the disc (102) is lifted due to dynamic force of flowing water creating free area for flow. When the water flow stops, the disc (102) turns under gravity due to self weight to close the valve (100).
The hinge (15) which bears the disc (102) comprises a shaft (104) rotatably fixed in bearings (107). The said disc (102) is fixed to the shaft (104) by means of a support plate (16). The said disc (102) is provided with a hole (17) enabling balancing water pressure across the valve when valve (100) is closed during operation.
Said shaft (104) sealably extends out from the shell (101) forming shaft extension (18). A gasket (109) is provided for sealing the interface between the shaft (104) and the shell (101). Rotary motion of the shaft (104) and in turn the closing and opening of

the valve (100) is controlled by a control unit (105) provided in juxtaposition of said shaft extension (18). The said control unit (105) comprising a composite hydraulic cylinder (19) is comprises of at least one hydraulic cylinder. Cylinder rod (20) extending out from the composite cylinder (19) is connected to said shaft extension (18) by means of linkage (21) and hinge pins (28) and (29), enabling the control unit (105) to control rotary motion of said shaft (104) and in turn the opening and closing motion of said disc (102).
According to the present invention, each of the said hydraulic cylinders of the composite hydraulic cylinder (19) is provided with a control circuit as shown which comprises a unidirectional flow control valve (24) connected between inlet and outlet ports (27) of the hydraulic cylinder by means of bypass pipes (26). The cylinder with its control circuit is fully filled with a hydraulic fluid. During rotary motion of the shaft (104) while closing and opening of the valve (100) the linkage (21) between the shaft (104) and the cylinder rod (20) moves the cylinder rod (20) in forward and return directions respectively, thus displacing hydraulic fluid. The said unidirectional flow control valve (23) offers free flow of hydraulic fluid when the shaft (104) turns during opening of the disc (102) enabling opening of the valve (100) without any resistance to flow. When the disc (102) is closing the orifice (14) and turning the shaft (104) in opposite direction, the unidirectional flow control valve (23) restricts the

water flow and hence the speed of closing of valve (100] is controlled by the flow control valve (23) according to preset flow control. The setting of the flow control valve (23] is decided according to analysis of the pipe line, to achieve precalculated result.
Preferable materials of construction of various components according to the present invention are as follows:
a) Shell, disc, flanges: - Mild Steel grade l.S. 2062 and equivalent
b) Material for seal any one selected from the group consisting of nitrile rubber, neoprene and water resistant elastomer.
c} Shaft and hinge pins : - Steel grade En 8 and equivalent.
d] Bearings: - Material selected any one from the group consisting of brass, gunmetal and a corrosion resistant bearing material.
Function of Valve (100)
1. Valve (100) opens gradually as pumping operation starts. Disc (102) is in full open condition when pumping is on. Disc (102) is held in open position due to velocity head of water available in the valve (100).

2. When pumping stops suddenly, velocity of water starts dropping & thereby velocity head available for holding disc [102] also reduces. Disc (102) starts falling down due to gravity force. This downward movement of disc [102] is controlled by external control unit (105) which allows movement of disc (102) at different speeds at different bands of closing. As an example valve is set to initial 50% rapid closure, next 30 % at slower speed & balance 20% at very low speed. This closing characteristic is decided according to surge analysis results of the pipe line. Multiple closing characteristics required are achieved using multiple cylinders in series or parallel installation.
Alternate embodiments of the present invention
According to first alternate embodiment of the present invention, the control unit (105) comprises plurality of hydraulic cylinders (22) connected in series to form a first composite cylinder unit (19A) as shown in Fig 6.
According to second alternate embodiment of the present invention, the control unit (105) comprises plurality of hydraulic cylinders (23) which are connected in parallel forming a second composite cylinder unit (19B) as shown in Fig 7.

According to third alternate embodiment of the present invention, the plurality of hydraulic cylinders are provided in series and parallel combination as shown in Fig 8.
According to fourth alternate embodiment of the present invention, as shown in Fig 5, the internal profile (PR) of bore (b), of hydraulic cylinder (19C) is varied in the axial direction of the cylinder (19C). This provides variable clearance shown as (Gl) and (G2) at different axial positions; between outer diameter of piston (P) and bore (B) of the hydraulic cylinder (19C). The bore (B) of the hydraulic cylinder is provided a profile (PR) varying at plurality of axial positions to control response of the valve, enabling to provide programmable control of the rotary motion of said shaft. This facilitates programmable control of closing of the valve (100) enabling the valve (100) to control surge pressure efficiently.
According to fifth embodiment of present invention out of the hydraulic cylinders according to first, second and third embodiments at least one hydraulic cylinder is provided with variable clearance between piston and cylinder in axial direction of the cylinder.
According to fifth alternate embodiment of the present invention, at least two of the plurality of hydraulic cylinders of said first to third embodiment are provided with common unidirectional flow

control valve with bypass pipes and the remaining hydraulic cylinders are provided with individual unidirectional flow control valve together with connecting bypass pipes.
The alternative embodiments described above enable setting of the hydraulically operated zero velocity valve according to the present invention, so as to reduce the surge pressure to a permissible value, which is decided on the basis of analysis of the pipe line.
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiments.
Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.
The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications

and alterations may be made without departing from the spirit and scope of the invention; which is defined by the scope of the following claims.
Advantages of invention
1. The present invention provides controlled closure of valve and start the closure as soon as the flow velocity of water starts reducing thus providing efficient surge pressure suppression.
2. The present invention provides clear flow passage for water when the valve is in open condition, thus offering minimum resistance to flow. This reduces the head loss. This is achieved without providing a bulge in the diameter of shell.
3. The present invention provides the valve which, require less space for installation.
4. The present invention obviates need of an internal cone or dome which are required in prior art valves.
5. The control unit according to the present invention is externally mounted facilitating ease of maintenance.

Hydraulically operated zero velocity valve (the valve) for
installation on water pipe lines for reducing surge pressures
comprising
a shell for housing components of the valve;
a body fixed inside the shell coaxial with internal diameter of
the shell; said body provided with an orifice to allow flow of
water through;
a disc enabled to close and open the orifice, said disc fixed by
hinge above said orifice vertically above axis of the shell;
said disc provided with a hole enabling balancing water
pressure across the valve when valve is closed during
operation;
said hinge comprising a shaft supported on bearings and
having an extension extending out jof the shell in sealable
manner;
said disc fixed to said shaft of the hinge by means of support
plate, thereby turning motion of the disc being imparted to
said shaft;
a control unit linked to said shaft extension enabling control of
turning motion of said shaft, thereby controlling closing and
opening of the orifice by said disc;
said control unit comprising of a composite hydraulic cylinder,
said composite hydraulic cylinder further comprising at least

one hydraulic cylinder with its control circuit; said hydraulic cylinder with its control circuit filled with hydraulic fluid; said control circuit comprising of bypass pipes connecting inlet and outlet oil ports of said hydraulic cylinder through an unidirectional flow control valve; thus providing free motion of the said shaft in the direction in which said disc turns to open the orifice and restricted motion of the said disc when it is closing said orifice;
said unidirectional flow control valve being set to a preset value;
thereby, enabling free opening of the valve and closing of the valve at a preset speed, to control surge pressure developed in the pipe line, said preset speed being determined according to surge analysis of the pipe line.
Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises plurality of hydraulic cylinders connected in series to form a composite cylinder.
Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises plurality of hydraulic cylinders which are connected in parallel, forming a composite cylinder.

4. Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises plurality of hydraulic cylinders connected in series and parallel combination,
5. Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises said hydraulic cylinder with internal profile of its bore varied in the axial direction of the cylinder, providing variable clearance at different axial positions between outer diameter of its piston and bore of the hydraulic cylinder enabling to provide programmable control of the rotary motion of said shaft.
6. Hydraulically operated zero velocity valve as claimed in claim 1 to claim 4 wherein said control unit comprises at least one hydraulic cylinder provided with variable clearance between piston and cylinder in axial direction of the cylinder as claimed in claim 5.
7. Hydraulically operated zero velocity valve as claimed in claim 1 wherein said control unit comprises at least two of the plurality of hydraulic cylinders are provided with common unidirectional flow control valve with bypass pipes and the remaining hydraulic cylinders provided with individual unidirectional flow control valve together with connecting bypass pipes.

Hydraulically operated zero velocity valve as claimed in claim 1 to claim 7 wherein material of construction of shell, disc and flanges is Mild Steel grade I.S. 2062 and equivalent.
Hydraulically operated zero velocity valve as claimed in claim 1 to claim 7 wherein material of construction of seal and gasket is any one selected from the group consisting of nitrile rubber, neoprene and water resistant elastomer.
Hydraulically operated zero velocity valve as claimed in claim 1 to claim 7 wherein material of construction of shaft and hinge pins is steel grade En 8 and equivalent.
Hydraulically operated zero velocity valve as claimed in claim 1 to claim 7 wherein material of construction of bearings is selected any one from the group consisting of brass, gunmetal and a corrosion resistant bearing material.
Hydraulically operated zero velocity valve as claimed in claim 1 as substantially described hereinbefore, with reference to the accompanying drawings.