FIELD OF THE INVENTION
The present invention relates to butterfly valves used in Hydro Electric Plants.
More particularly, the invention relates to an adjustable stopper cum lock device
for improved sealing of valve doors and valve seats in large butterfly valves.
BACKGROUND OF THE INVENTION
Butterfly valves are used in low and medium head hydroelectric plants for
stopping water under emergency or for maintenance of downstream components
of the plant. As shown in figure 1, the known butterfly valve essentially consists
of a body (1) in which rotates a door (2) with a rubber seal (3) on its periphery.
In the open position of the valve, when water flows through the valve, the door
(2) is parallel to the flow. When the valve is to be closed, the door (2) is turned
through 90° so that the door is perpendicular to the flow. The valve door (2) is
generally designed to have a closing tendency to facilitate emergency closure. In
the closed position, sealing of water takes place by the door seal (3) pressing
against a stainless steel valve seat (4).
In large butterfly valves, the deflection of the body (1) and door (2) due to
hydraulic load is quite significant and there is an optimum angular position of the
door (2) with respect of the body (1) which gives the best sealing performance.
When installed at site, the closed position of the door (2) with respect to the
body (1) is dictated by the piston (8) of an oil operated hydraulic cylinder (5)
touching bottom end (10) of a hydraulic cylinder (5). The present configuration
of closed position of the valve either hinders or is not convenient for adjusting
the angular position of the door (2) for best sealing. The present innovation is
about a device to adjust the door (2) for best sealing and also have a built in
provision for locking the door (2) in closed position.

It is known that sealing performance of large butterfly valve is dependent upon
the deflection patterns of the door (2) and body (1) of the valve. Optimum
position of the Butterfly valve door (2) with respect to the valve Body (1) may
always not be in mechanically closed position, but depends generally upon
deflection patterns. Deflection patterns of the upper and lower portion of the
door (2) are dependent upon the size of the door, head and eccentricity. The BF
valve door (2) of the prior art having stopper, has some drawbacks. For
example, in the prior art shown in figure 1, the position of locking boss of the
locking pin (11) corresponds to mechanical closed position of the door and there
is no provision of adjustment for better sealing.
The prior art shown in figure 2, has stopper for BF valve door (2) which touches
the bottom end of hydraulic cylinder (10) by virtue of piston(8). The locking
arrangement comprises a collar at eye end (28) being clamped with respect to
the hydraulic cylinder by means of special bolts (29). These special bolts and
collar of the eye end are designed to sustain full force of the cylinder.
Adjustment of the closed position of the door is done at site while installing the
hydraulic cylinder; but is very cumbersome.
It is therefore an object of the invention to propose an adjustable stopper cum
locking device for large butterfly valve door which allows an improved sealing of
the valve by taking into account the deflection pattern of the body and door of
the valve.
SUMMARY OF THE INVENTION
According to the invention, there is provided an adjustable stopper cum locking
device for improved sealing of valve doors and valve seats in large butterfly
valves. The device consists of a first plate welded to a lever arm resting on a

large spherical headed screw which is fixed on a second plate projecting from
the butterfly valve body. A locking bolt is provided to lock the BF Valve door with
respect of the body thus preventing any inadvertent opening of the valve when
any maintenance activities is under progress downstream of the valve.
The locking bolt can pull the door towards closure whereas the stopper screw
can push the door in the opening direction, therefore a fine adjustment of the
position can be done to achieve the best sealing position.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows a butterfly valve of the prior art.
Figure 2 - shows another butterfly valve of a the prior art.
Figure 3 - shows an adjustable stopper for butterfly valve according to the
invention.
Figure 4- shows an Isometric View of Stopper Cum locking device for
butterfly valve according to the invention.
Figure 5 - shows close-up Isometric View of the device of figure 4.
Figure 6 - sectional plan view of the device through the Locking Bolt
Arrangement.
Figure 7 - sectional plan view of the device through Spherical Headed Stopper
Screw Arrangement.

Figure 8 - side view showing Slotted Ring Nut & Rectangular Steel Piece
Arrangement.
Figure 9 - Exploded View of the device of figure 4.
DETAILED DESCRIPTION OF THE INVENTION
As shown in figure 4, the doors of the butterfly valve are operated by oil
operated hydraulic cylinders (5). Opening of butterfly valve is invariably by oil
operated cylinders (5) whereas closing can be either by dead weights (6)
attached to lever arm (7) or by both dead weight (6) and closing force of
hydraulic cylinders (5). Butterfly valve gets stopped in open position when
piston (8) touches the hydraulic cylinder's top end (9). The close position of
butterfly valve door (2) gets dictated by the piston touching the cylinder bottom
end (10). In case of prior art shown in figure 1, this closed position should also
correspond to the position when holes of locking pin (11), lever arm (7) and
body (1) are in alignment. In prior art of figure 1, no scope is available for
adjustment for optimum position. In prior art of figure 2, even though there is no
constraint of locking pin (11) but adjustment by means of turning the piston rod
(12) or by turning the eye end of the servomotor and shimming between
servomotor bottom bracket (14) and foundation plate (15) is very cumbersome.
As shown in figure 4, the device comprises of first projecting plate (17)
projecting from the lever arm (7). The first projecting plate (17) in turn is
supported by a first plurality of triangular ribs (18) to give strength/rigidity. The
first projecting plate (17) and in turn the lever arm (7) gets stopped on a
spherical headed stopper screw (19) which is fixed in a second plate (20)
projecting from the valve body (1). This second projecting plate (20) from the

valve body (1) is additionally supported by a second plurality of ribs (21) welded
to the body (1).
The first projecting plate (17) of the lever (7) has a threaded hole (22) into
which engages a locking bolt (23) to lock the lever (7) and in turn the door (2)
with respect to the body (1). The head of the locking bolt (23) is provided with a
spherical bottom to sit on a spherical washer (24) which in turn rests on the back
side of the second plate (20) projecting from the body. This spherical bottom
bolt (23) and the spherical washer (24) arrangement compensate the
misalignment between axis of the threaded hole (22) in the door (2) and the
back of the second plate (20) of the body (1).
The spherical headed stopper screw (19) is provided with at least six holes on
the end opposite to the spherical end for the purpose of turning the screw (19)
by a tommy bar for adjusting the screw position. A slotted ring nut (25) is
provided to lock the stopper screw (19) after adjustment. For the purpose of
locking a rectangular steel piece (26) is put in a slot of the slotted ring nut (25)
and welded to the second projecting plate from the body. The locking bolt (23)
pulls the lever (7) along with the door (2) towards the body (1). On turning the
stopper screw (19) in one direction it pushes the lever (7) with the door (2)
away from the body (1) whereas turning the stopper screw (19) in the reverse
direction, it allows the lever (7) with the door (2) to come towards the body (1)
when pulled by the locking bolt (23).
Thus by the pushing action of the stopper screw (19) and pulling action of the
locking bolt (23) the angular position of the door (2) with respect to the door
seat (4) in the body (1) can be very precisely adjusted to achieve the improved
sealing performance of the butterfly valve.

LIST OF ITEMS
1. Butterfly Valve Body
2. Butterfly Valve Door
3. Rubber Seal
4. Stainless Steel Seat
5. Hydraulic Cylinder
6. Dead Weight
7. Lever/Lever Arm
8. Piston
9. Cylinder Top End
10. Cylinder Bottom End
11. Locking Pin
12. Piston Rod
13. Eye End
14. Bottom Bracket
15. Foundation Plate
16. Upstream Inlet Pipe
17. First Projecting Plate
18. Triangular Ribs
19. Spherical Headed Stopper Screw
20. Second projecting Plate From Body
21. Ribs
22. Threaded Hole
23. Locking Bolt
24. Spherical Washer
25. Slotted Ring Nut
26. Rectangular Steel Piece
27. Locking Boss
28. Collar of Eye End
29. Special Bolt

WE CLAIM
1. An adjustable stopper cum locking device for large butterfly Valves for
improved sealing of valve door and vale seat comprising:
a first projecting plate (17) welded to lever arm (7) which rests on a
spherical headed stopper screw (19) which is fixed in a second plate (20)
projecting out from valve body (1); a locking bolt (23) insertable into a
threaded hole (22) configured in the first projecting plate (17) of a lever
to lock the lever (7) with respect to the valve body (1), the spherical
headed stopper screw (19) and the locking bolt (23) in combination is
enabled to push or pull the door (2) with respect to the body (1) to place
the valve in an optimum sealing position, the spherical headed stopper
screw (19) having holes at the opposite end for turning by a tommy bar
and projectingly fixed from the valve body (1) on the second plate (20);
the screw (19) is locked by a slotted ring nut (25) by inserting a
rectangular steel piece (26) in the slot, wherein the locking bold head (23)
comprises a spherical back to sit on a spherical washer (24) to absorb
misalignment between the axis of the threaded hole (22) in the first
projecting plate (17) of the lever arm (7) and the second projecting plate
(20) on the body (1).