FIELD OF INVENTION
The present invention generally relates to a locking arrangement. More particularly, the
present invention relates to a locking device for gate valves applicable to industrial use.
BACKGROUND OF THE INVENTION
The flow of liquids or gases are generally conveyed by using tubular section in all steel
plants and engineering plants. The control of flow is exercised by providing different
types of valves like gate valve, ball valve, plug valve etc. in the piping work in the
system. Many a time it is required to maintain the position of valve either opening or
closing in the process especially while doing any maintenance work. Many engineering
and manufacturing plants handle different types of poisonous gases or liquids in their
process. The flowing medium may be used at very high temperature or pressure also.
This type of process is having potential hazards. In such type of cases it is urgently
required an isolation of the medium from the system. The purpose of positive isolation
is to ensure the prevention of injury to the personnel or damage of equipment or
dangerous occurrences during repair and maintenance of equipment or system.
An US Patent No. 535, 833 entitled "Gate valve locking arrangement" which discloses a
teaching of a gate valve locking arrangement in which a steel bracket is clamped on a
portion of the truss extending upwardly from the valve bonnet and supporting the gate
valve spindle and wheel. The bracket having a rigid bar extending upwardly and capped
by a L-shaped member seating against the inside of the wheel. The bracket may be
secured in a fixed portion relative to the wheel by a cylindrical lock, having a recess into
which the vertical portion of the L-shaped member is inserted and locked or by a
padlock in certain applications.
Another US Patent No. 7219685 entitled a "Gate valve locking device" which discloses a
teaching of a locking device for gate valves utilizes an available lock and avoids the
necessity of having no chain or weld the lock to the bonnet or other stationery portion
of a standard gate valve. The locking device includes a bracket, which mounts securely
to one of the truss members of the gate valve. The bracket also includes an upwardly
projecting mast, which is inserted between the adjacent spokes of the hand wheel. A
cap is seated onto the hand wheel and the mast of the bracket installed on the gate
valve. The cap includes a mast port through which the upper end of the mast projects
when the cap is seated on the hand wheel. In certain embodiments, the cap covers all
the spokes on the hand wheel and has a member of downwardly projecting spaced
spoke detents that are inserted into the openings between the adjacent spokes of the
hand wheel. The secure and easy installation of the cap on to the mast of the bracket
and the hand wheel prevents rotation of the hand wheel and adjustment of the valve.
Unfortunately, the locking device as disclosed in the above two prior patent have
certain shortcomings. Specifically, if the bracket only engages one of the truss
members, it is not securely mounted to the valve. The bracket is prone to movement on
the truss and the hand wheel can be rotated even when the locking device is installed.
The embodiment of the locking device which mounts to both the truss member may
offer a more secure attachment, but installation and remove is often difficult and
cumbersome. Moreover, the bracket often interferes with the stem packing to loosen
and or damage those components resulting leakage from valve.
Additionally, many valve hand wheels have 3, 5 or 6 spokes spaced equally at about
120°, 72° or 60° respectively. Even if the device is installed correctly and securely, the
vertical portion of the L-shaped member or mast projecting between the spokes does
not entirely prevent rotation of and tampering with the hang1 wheel. For example, if
such a locking device is installed on a gate valve with a 3 spoke hand wheel, the hand
wheel could still be rotated up to 120° causing an unauthorized adjustment to the valve
before the locking device prevents further rotation and adjustment.
A further US Patent No. 6,164,318 entitled "valve locking system" which discloses a
teaching of a valve locking system for safely and economically locking out control
valves. The valve locking system includes a valve locking assembly for preventing,
manipulation of a valve including a rotating handle. The handle includes at least one
aperture extending through the handle. The assembly includes a brace designed for
coupling around the neck of the valve such that the brace is preventing from rotating
around the neck of the valve. A cable includes a first end loop and a second end loop.
The first end loop is coupled to the brace. The second end of the cable is insertable
through the aperture in the handle. A locking member for coupling the first end loop to
the second end loop such that the cable ties the handle to the brace whereby the
handle is prevented from being rotated.
Unfortunately, certain people or even organizations are tempted to tamper with setting
of gate valve and to do so, the cable is cut and staple of a padlock is sawed. Quite
frequently, tampering with a gate valve to the extent of changing its setting even to the
extremes of shutting it off completely or fully opening it may produce disastrous
consequences. For example if the flow of water to a building is shut off none of its
automatic sprinklers may work with the result that there would be no automatic
suppression of a fire in the building. In this situation of a pipe line conducting the flow
of oil or water, shutting off a gate valve may result in shutting down pumps or even
causing damage to the pumps which do not have means to respond to a flow stoppage.
Therefore, a need exists for a secure, effective and easily implemented device to
prevent unauthorized, inadvertent or otherwise undesired manipulation and adjustment
of gate valve that does not suffer from these and other problems associated with prior
art locking devices.
Present invention is a simple mechanism which does not allow gate valve wheel to
rotate in any direction when placed in proper position. This can be locked and the
mechanism can not be taken out from wheel of the gate valve.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose an improved positional
locking device which maintains security and safety of flowing medium.
Another object of the present invention is to propose an improved positional locking
device which arrests the theft of valuable flow media.
A further object of the present invention is to propose an improved positional locking
device which is handy and easy to operate.
SUMMARY OF THE PRESENT INVENTION
Accordingly, the present invention is provided with a positional locking device (L) for a
gate valve, in particular gate valve having a long body structure and a driving wheel
containing a plurality of in build cast spokes with a rim, the device characterized in that
it comprises of a first part (1) consisting a single bar member having at least two ring
frame structures at both end of two parallel arms and middle part having a oblique 'L'
shaped configuration and a second part consisting a solid cylindrical locking pin (4)
having a larger diameter flange (5) at first end and a through and through hole (6) at
second end and a third part consisting a lock pad (7) having a latch (8) that can be
passed through a hole (6) of locking pin (4) and locked by means of a key characterized
in that the parallel arm of said first part are inserted from the top through a specific
spoke of the hand wheel and are passed through the side structure of the gate valve,
are being locked after entering the locking pin through the said ring structure, by
means of a locking pad after passing the latch through the holes of locking pin by a
key.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l - shows a schematic diagram of isometric view of the first part, second part and
third part of the locking device.
Fig-2 - shows a schematic diagram of isometric view of three parts in assembled
condition to form locking device.
Fig.3 - shows a schematic diagram of locking device mounted on the gate valve as per
present invention.
DETAILS DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The Improved locking device (L) comprising of three parts, First part (1)
consisting of a bar member having at least two right frame structure (2,3)
at both end and an oblique 'L' shape configuration is,made by bending the
middle part of the bar member. A second part consisting of a cylindrical
locking pin (4) having a flange (5) of higher diameter than that of the body
of the pin at first end and a through and through hole (6) at the second
end. A third part consist of a lock pad (7) having a lautch (8) of such a
diameter that it can pass through the hole (6) of the second part (4).
At first, the locking device (L) is inserted into a spoke (9) of the driving
wheel (10) from a side end and allows the arms of the device to pass
through one side structure (11) of the gate valve body. Thereafter, the
hole (6) end of the locking pin (4) is inserted from first ring frame structure
(2) and allows to pass through second ring structure (3) such that the
flange end (5) of locking pin is fixed at ring frame structure (5) and hole
(6) end of locking pin (4) comes out through the ring frame structure (3).
A latch (8) of a locking pad (7) is inserted into the hole (6) of locking pin
(4) and passes through the other hole (6) end and locks the lock pad by
means of a key.
WE CLAIM
1. A positional locking device (L) for a gate valve, in particular gate valve having a
long body structure and a driving wheel containing a plurality of inbuild cast
spokes with a rim, the device characterized in that it comprises of:
- a first part (1) consisting a single bar member having at least two ring frame
structures at both end of two parallel arms and middle part having a oblique 'L'
shaped configuration;
- a second part consisting a solid cylindrical locking pin (4) having a larger
diameter flange (5) at first end and a through and through hole (6) at second
end;
- a third part consisting a lock pad (7) having a latch (8) that can be passed
through a hole (6) of locking pin (4) and locked by means of a key;
characterized in that the parallel arms of said first part are inserted from the top
through a specific spoke of the hand wheel and are passed through the side
structure of the gate valve, are being locked after entering the locking pin
through the said ring structure, by means of a locking pad after passing the latch
through the holes of locking pin by a key.
2. The device as claimed in claim 1, wherein all parts are made of steel material.
3. The device as claimed in claim 1, wherein the device locks the driving wheel with
side structure of gate valve body.
4. The device as claimed in claim 1 wherein said device is adaptable to such gate
valve which has a long body structure.
5. A locking device (L) of gate valve substantially described and illustrated herein
with reference to accompanying drawings

The present invention relates to a positional device (L) for a gate valve, in particular
gate valve having a long body structure and a driving wheel containing a plurality of
inbuild cast spokes with a rim, the device characterized in that it comprises of a first
part (1) consisting bar member having at least two ring frame structures at both end
and a middle part having a oblique V shaped configuration and a second part
consisting a cylindrical locking pin (4) having a larger diameter flange (5) at one end
and a through and through a hole (6) at one end and a through and through hole (6) at
the other end and a third part consisting a lock pad(7) having a latch (8) that can be
passed through a hole (6) of locking pin (4) and locked by means of a key wherein
locking of the valve either in full open condition or in full closing condition or at any
intermediate stage can be secured by selecting the appropriate spoke and to insert the
device therein.