FIELD OF THE INVENTION
The present invention generally relates to a locking arrangement.
More particularly, the present invention relates to an improved locking
device for plug valve applicable to industrial use.
BACKGROUND OF THE INVENTION
In typical steel plants or integrated Engineering industry, the flow of
liquid or gases are normally carried out by using tulutar section means.
The restriction of flow of fluid is done by providing different types of
valves like gate valve, ball valve, plug valve etc on the path of fluid
flow in the pipeline in the system. Some times it is required to maintain
the position of the valve, either opening or closing in the process
specially while doing any maintenance work. There are some
Engineering and manufacturing plants who handle different types of
poisonous gases or liquids in their process. They have to take special
care and security in respect of their flowability in the system. There
are some flowing medium that may be used at very high temperature or
pressure also and this type of process is involved many potential

hazards. In such cases, it is required to positively isolate 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. Present
invention is a simple mechanism which does not allow manually
operated ball valve and plug valve or any valve with 90 degree rotation
for full opening and closing to rotate in any direction when placed in
proper position. This can be operated from the valve rotating
arrangement.
OBJECTS OP THE INVENTION
It is therefore, an object of the present invention to propose a locking
device for plug gate which ensures the security and safety of the
flowing medium.
Another object of the present invention is to propose a locking device
for plug gate which abstrains from manually operation of the plug valve.

A further object of the present invention is to propose a locking device
for plug gate which ensures simplicity in operation mechanism.
A still further object of the present invention is to propose a locking
device for plug gate which arrests the theft if valuable liquid flowing
through it
SUMMARY OF THE PRESENT INVENTION
The present invention comprising of atleast two individual parts, first
part is a inverted 'L' shape member connected at a corner point of a
square shaped frame structure at one end insertable in the square
shape spindle of the plug valve and other end of inverted fL* shape part
having a hole trough which a latch of the lock can be fastened. The
second part having a hole at one end and other end having a circular
frame structure by joining two circular halves which are mounted over
a cylindrical pipe and fastened by nuts and bolts and sealed. According
to the requirement for opening or closing of the valve, the holes of two

parts are taken together and locked them by entering a latch of a lock
through these two holes. By this locking arrangement a manually operated
ball valve and plug valve of any size can be locked at fully closed position or
at fully opened position.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l - shows a schematic diagram of a plug valve mounted with the locking
device.
Fig.2 - shows a schematic diagram of the individual parts of the locking
device.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION
As shown in Fig.2, the improved locking fixture (1) for valves comprising of
at least two parts, a movable and detachable first part (2) is provided with a

inverted 'L' shaped member. At one end of the long arm of first part having
a square shaped frame structure (3) insertable in the square shaped spindle
(4) of valve (5) which enable the valve opening or closing by rotating the
first part form 0° (Zero degree) to 90° (Ninety degree) in clockwise or
anticlockwise direction. The other end of the first part has a hole (6) in the
short arm. A fixed second part (7) having a plurality of holes (8,16) at one
member and the other end is provided with a circular frame structure (9) by
joining two circular halves (10, 11) which are mounted over a cylindrical
pipe (12) and fastened by nut and bold (13,14) and sealed. At any opening or
closing position of the valve, square frame (3) of first part (2) is inserted into
a spindle (4) of valve (5) and the hole (6) of first part is taken together with
the hole (16) of second part (7) and locked by means of a locking pad (15) as
shown in assemble condition in Fig. 1. This fixture is operatable in all types
of marketable gate valve, plug valve and ball valve wherein the opening and
closing are performed by 90° rotation of gate and possess a square shaped
spindle and the fixture can be adapted in any size of pipe diameter.

WE CLAIM
1. A locking fixture for valves provided with a square shaped spindle
rotatable from 0° to 90° in clockwise or anticlockwise for opening and
closing operation comprising:
- at least two parts, a movable and detachable first part (2) having
an inverted 'L' configuration with a hole (6) in short arm end
and a square shaped frame structure connected at corner (3) at
long arm end and a fixed second part (7) having a plurality of
holes (8,16) at one member and a circular shaped frame
structure (9) at the other end that can be adapted in any size of
pipe diameter;
- the square shaped frame structure (3) of the first part (1) is
insertable to a square shaped spindle (4) of the valve (5);

- the circular frame structure (9) of second part (7) consisting of
two circular halves (10,11) which are mountable on the pipe
(12) by means of rigid fasteners (13,14); and
- the hole (6) of first part (2) and the hole (16) of second part (7)
are locked by means of a locking pad (15) and the hole (17) of
first part (2) is fastened with the hole (8) of second part (7) by
means of a fastener.
characterised in operating the valve (5) either in full opening
condition or in full closing condition wherein the said fixture is
operatable in all types of marketable gate valve, plug valve and
ball valve where the opening or closing are performed by 90
degree rotation of gate and possess a square shaped spindle.
2. The locking fixture as claimed in claim 1 wherein the parts (2, 7) are
made of steel materials.

3. The locking fixture as claimed in claim 1 wherein any marketable
lock pad can be accommodated.

The present invention relates to a locking device for valves provided with a
square shaped spindle rotatable from 0° to 90° for opening and closing operation
comprising atleast two parts, a first part (2) having an inverted 'L' configuration
with a hole (6) in short arm end and a square shaped frame structure connected
at corner (3) at the long arm end and a second part (7) having a plurality of
holes (8,16) at one member and a circular shape frame structure (9) at the other
end; the square shaped frame structure (3) of the first part (1) is insertable to a
square shaped spindle (4) of the valve (5); the circular frame structure (9) of
second part (7) consisting of two circular halves (10,11) which are mountable on
the pipe (12) by means of rigid fasteners (13,14) and the hole (6) of first part
(2) and the hole (16) of second part (7) are locked by means of a locking pad
(15) and the hole (17) of first part (2) is fastened with the hole (8) of second
part (7) by means of a fastener characterised in operating the valve (5) either in
full opening condition or in full closing condition.