VALVE CLOSING MECHANISM BRACKET AND GAS SUPPLY SYSTEM
Field of the Invention
The invention relates to a valve closing mechanism bracket for use in closing
spindle-controlled valves of the type used with gas storage vessels, and a gas supply
system using the valve closing mechanism bracket.
Background of the Invention
Toxic or hazardous fluids such as chlorine are often stored in cylinders equipped
with a valve which is designed to be turned on and off by means of a rotatable spindle,
rotation of which serves to move a valve member relative to a valve seat. If there is a
leakage of the toxic fluid downstream of the storage vessel, it is essential that the valve is
closed rapidly and reliably without risk to personnel.
It has previously been proposed to provide a valve closing mechanism to close a
valve when a detector senses the presence of a toxic or hazardous gas in the surroundings.
For example, Australian Patent No. 667504 discloses a valve closing mechanism which
uses a compressed air cylinder and a one-way drive to rotate a spindle of the valve on
detecting a toxic or hazardous gas. However, the applicant has identified drawbacks
associated with previous valve closing mechanisms, and has determined that it would be
advantageous to provide an improved valve closing mechanism.
Examples of the present invention seek to provide a valve closing mechanism
bracket which overcomes or at least alleviates one or more disadvantages associated with
existing valve closing mechanisms.
Summary of the Invention
In accordance with one aspect of the present invention, there is provided a valve
closing mechanism bracket including a coupling for attaching the bracket to a valve body,
a mounting arranged to mount an actuator for automatically closing the valve in the case of
a predetermined event, a support structure for supporting the mounting relative to the
coupling, and an adaptor, wherein the mounting is arranged for fixedly fastening the
actuator to the mounting in a position in which, when the coupling is in place on the valve
body, an engagement member of the actuator is rotationally engaged with a spindle of the
valve such that rotation of the engagement member rotates the spindle to close the valve,
and wherein the coupling is adapted to be decoupled from the valve body for removal of
the bracket from the valve body with the actuator fixedly fastened to the mounting,
wherein the mounting is used to fixedly fasten a first type of actuator directly, and wherein
the mounting is used to fixedly fasten a second different type of actuator via the adaptor.
Preferably, the mounting includes a mounting plate which is adapted to receive
different types of actuators. More preferably, the mounting plate is adapted to receive a
pneumatic actuator or an electric actuator.
In one form, the mounting plate is able to be used to fixedly fasten a first type of
actuator directly, and wherein the mounting plate is able to be used to fixedly fasten a
second different type of actuator via an adaptor. Preferably, the mounting plate is provided
with apertures for fastening to the first type of actuator and the adaptor is arranged to be
fastened to the same apertures.
Preferably, the bracket is formed as a unitary piece. More preferably, the bracket is
formed by machining of carbon steel.
Preferably, the coupling comprises a pair of opposed legs having abutment surfaces
which are clamped to either side of the valve body.
In a preferred form, the bracket extends generally in a direction of an axis of
rotation of the spindle of the valve. More preferably, the bracket is arranged to support the
actuator with a axis of rotation of the actuator co-axial with the axis of rotation of the
spindle of the valve.
Preferably, the bracket is arranged to support the actuator with a longitudinal axis
of a body of the actuator co-axial with the axis of rotation of the spindle of the valve.
It is preferred that the engagement member is in the form of a sleeved key which
fits over the spindle, and the coupling is arranged such that the bracket is removed from the
valve body by moving the bracket in the direction of the axis of the spindle relative to the
valve body.
Preferably, the support structure is stepped inwardly to accommodate a yoke fitted
over the coupling of the bracket.
Preferably, the valve body controls the flow of gas from a vessel, and said
predetermined event is the detection of said gas by a gas sensor.
In accordance with another aspect of the present invention, there is provided a gas
supply system including at least one gas storage vessel having a valve controlled outlet and
associated valve closing mechanism including a bracket as described above, the system
further including a controller for controlling operation of the or each valve closing
mechanism, wherein the controller includes a gas sensor and the controller is adapted to
initiate operation of each actuator to close each valve body in response to sensing the gas
contained in the storage vessel.
Preferably, the system includes a plurality of the gas storage vessels, and the
controller controls the valve closing mechanism of each of the gas storage vessels. More
preferably, the controller is arranged to control one or more of the valve closing
mechanisms remotely.
Brief Description of the Drawings
The invention is described, by way of non-limiting example only, with reference to the
accompanying drawings, in which:
Figures l a to Id show different views of a valve closing mechanism bracket in
accordance with an example of the present invention;
Figure 2 shows the valve closing mechanism bracket located on a cylinder valve;
Figure 3 shows the valve closing mechanism bracket used with a pneumatic actuator
mechanism;
Figure 4 shows the valve closing mechanism bracket used with an electric actuator
mechanism;
Figure 5 shows a valve closing mechanism on a cylinder valve with a yoke fitting
vacuum regulator;
Figure 6 shows a control system for a valve closing mechanism with a pneumatic
actuator;
Figure 7 shows detail of the valve closing mechanism bracket used in combination
with an adapter;
Figure 8 shows a control unit for an electric actuator mechanism;
Figure 9 shows a base of the control unit of Figure 8;
Figure 10 shows a control unit for a pneumatic actuator mechanism;
Figure 11 shows a base of the control unit shown in Figure 1Q; and
Figure shows a control unit and associated chlorine sensor on a stand.
Detailed Description
With reference to Figures l a to Id, there is shown a valve of closing mechanism
bracket 10 which is able to be used with either a pneumatic actuator mechanism or an
electric actuator mechanism. Advantageously, the valve closing mechanism bracket 10
enables removal of the valve closing mechanism from the storage vessel as a unit,
facilitating rapid changeover when it is necessary to replace a depleted storage vessel.
More specifically, the valve closing mechanism bracket 0 includes a coupling 2
for attaching the bracket 10 to a valve body 14, a mounting 16 arranged to mount an
actuator for automatically closing the valve in the case of a predetermined event, and a
support structure 18 for supporting the mounting 16 relative to the coupling 12. The
mounting 16 is arranged for fixedly fastening the actuator to the mounting 16 in a position
in which, when the coupling is in place on the valve body 14, an engagement member
of the actuator is rotationally engaged with a spindle of the valve such that rotation of the
engagement member rotates the spindle to close the valve. The coupling 12 is adapted to
be decoupled from the valve body 1 for removal of the bracket 10 from the valve body 4
with the actuator fixedly fastened to the mounting 16. Figure 2 shows the valve closing
mechanism bracket 10 coupled to a valve body 14, with the mounting 16 arranged for
attachment to an actuator arranged in line with an axis of rotation of the spindle of the
valve.
In the examples shown, the mounting 16 includes a mounting plate 20 which is
specifically adapted to receive different types of actuators. In particular, the mounting
plate 20 is adapted to receive a pneumatic actuator 22 or an electric actuator 24. The valve
closing mechanism bracket 10 is generally arranged as having a pair of legs 26 which
extend from the coupling 12 at one end to the mounting plate 20 at the opposite end. The
legs 26 terminate at opposite sides of the mounting plate 20 to provide adequate support to
the mounting plate 20, and use a brace 28 which serves to brace the mounting plate 20
relative to the legs 26. The mounting plate 20 has a central aperture 30 to allow the
engagement member of the actuator to extend through the mounting plate 20 for
engagement with the spindle of the valve.
Figures 3 and 4 sho the valve closing mechanism bracket 10 used with a
pneumatic actuator 22 and an electric actuator 24. With reference to Figure 3, the
mounting plate 20 is used to fixedly fasten the pneumatic actuator via an adapter 32. In
Figure 4, the mounting plate 20 is used to fixedly fasten the electric actuator 24 directly.
This is achieved by providing the mounting plate 20 with apertures 34 which are used for
fastening the electric actuator 24 or the adapter 32. The adapter 32 acts as a spacer to
accommodate the relatively longer engagement member 36 of the pneumatic actuator 22
when compared to the engagement member 36 of the electric actuator 24.
Figure 5 shows the valve closing mechanism bracket 10 with an electric actuator 24
fitted to the mounting plate 20, with a yoke fitting vacuum regulator 38 fitted around the
outside of the coupling 12. The support structure 18 is stepped inwardly to accommodate
the yoke fitting vacuum regulator 38 over the coupling 2 of the bracket 10.
Figure 6 shows a control system 40 for controlling the valve closing mechanism
having the pneumatic actuator 22.
With reference to Figure 7, there is shown detail of the valve closing mechanism
bracket 10 fitted with the adapter 32. As can be seen, the adapter 32 has four apertures 34
which are used to fasten the adapter 32 to the mounting plate 20. The adapter 32 has a
central aperture 42 which is arranged to be positioned in line and coaxial with the central
aperture 30 of the mounting plate 20. The central aperture 42 of the adapter 3 is threaded
for receiving a threaded body of the pneumatic actuator 22.
The valve closing mechanism bracket 10 may be formed as a unitary piece, for
example by machining of carbon steel. The coupling 12 comprises end portions of the pair
of opposed legs 26 having abutment surfaces 44 which are clamped to either side of the
valve body 14. The end portions of the legs 26 may have apertures to receive a fastener to
tighten/loosen the clamping of the coupling 12 on the valve body 14. The bracket 0
extends generally in a direction of an axis of rotation of the spindle of the valve, and is
arranged to support the actuator 22/24 with an axis of rotation of the actuator 22/24 co
axial with the axis of rotation of the spindle of the valve. The valve closing mechanism
bracket 10 may also be arranged to support the actuator 22/24 with a longitudinal axis of a
body of the actuator 22/24 co-axial with the axis of rotation of the spindle of the valve.
This is advantageous as electric and pneumatic actuators are commonly in the form of a
device having an elongated body with an engagement member 36 which rotates about an
axis parallel to a longitudinal axis of the actuator body.
The engagement member 36 may be in the form of a sleeved key which fits over
the spindle, and the coupling 2 is arranged such that the bracket 10 is removed from the
valve body 14 by moving the bracket 10 in the direction of the axis of the spindle relative
to the valve body 14. The valve body 14 controls the flow of gas from a vessel, and the
predetermined event which results in automatic closure of the valve is the detection of the
gas by a gas sensor 46.
With reference to Figures 8 to 12, there are shown features of a gas supply system
using the valve closing mechanism bracket 10 as described above. More specifically, there
is provided a gas supply system including at least one gas storage vessel having a valve
controlled outlet and associated valve closing mechanism including a bracket 10. The
system includes a controller 48 for controlling operation of the or each valve closing
mechanism. The controller 48 is in communication with the gas sensor 46 and the
controller is adapted to initiate operation of each actuator 22/24 to close each valve body
14 in response to sensing the gas contained in the storage vessel.
The system may include a plurality of gas storage vessels, and the controller 48
may control the valve closing mechanism of each of the gas storage vessels. The
controller 48 may be arranged to control one or more of the valve closing mechanisms
remotely. This may be achieved by way of the controller 48 incorporating a modem 50
which is capable of transmitting information to/from a remote location. The controller 48
also includes a battery 52, UPS power supply 54, interface relay 56 and duct 58. The base
of the controller 48 has ports 60 for connection to a plurality of electric actuators 24, as
well as a port 62 for connection to the chlorine gas sensor 46.
Figures 10 and 11 show a controller 64 for controlling a gas supply system using
pneumatic actuators 22, and is generally similar to the controller 48 shown in Figures 8
and 9. The controller 64 includes air outputs 66, an air supply port 68, and exhaust
silencers 70. Both controller 48 and controller 64 include an on/off switch 72, a 240 V
input port 74, and an external contact port 76.
Figure 12 shows a stand 78 which supports the controller 48/64, as well as the
chlorine gas sensor 46.
Further examples and variations of the valve closing mechanism bracket and gas
supply system are discussed below.
The connection between the spindle and the engagement member (which may be in
the form of a transmitting key), support clamping bracket and actuator is of a quick release
slip off nature so that in the event of valve closure being effected by the actuator, access to
the spindle can be done rapidly to allow the valve to be opened (when safe to do so) for
example by manual manipulation of the spindle with the aid of a suitable tool.
Preferably the actuator is in the form of an electric driven motor with set torque
(eg. 30 to 40Nm) with internal limit switches to indicate the open and closed positions.
Alternatively, the actuator is in the form of a pneumatic driven actuator comprising
of a pawl and ratchet drive, for example of the type commonly employed in ratchet
spanners.
The storage vessel may be of the common cylinder type used for storage of gases
such as chlorine. The cylinder may have an outlet fitted with a conventional valve
assembly having an outlet through which the gas is supplied to downstream equipment
when the valve assembly is open. Valve closure and opening is effected by rotation of a
spindle which at its upper end terminates in a squared section for co-operation with
suitable tool. In contrast with conventional practice, instead of closing the valve manually
with a tool, the cylinder is equipped with an automatic valve closing mechanism.
The mechanism comprises a support clamping bracket which is non-rotationally
fitted to the body of the valve assembly by means of a suitable clamping arrangement. The
square section of the spindle and electrical or pneumatic actuator is connected using the
transmitting key suitable for both types of actuators.
The transmitting key, support bracket and actuator are so designed that rotational
movement of the transmitting key is transmitted to the spindle to turn in the same direction
(closed).
The support bracket is so designed to allow fit and suitable clamping of the
actuators if the valve has a standard vacuum regulator yoke fitting or not.
The support bracket is designed to be fitted and fixed to the either type actuator
with tightening nuts if the electrical actuator is used or screwed thread fitting in the support
bracket if the pneumatic actuator is used.
The support bracket is designed as to permit the quick release from the squared
spindle section without the need for any special tools, eg. by loosening the tightening wing
nut on the support bracket and lifting off the bracket and actuator in one motion.
Compressed air is supplied to the pneumatic actuator via a regulator and control
unit which serves to supply regulated air pressure to the pneumatic actuator thereby closing
the valve spindle to the desired torque and turning off the actuator after a pre programmed
time.
In practice there will usually be a number of cylinders each equipped with its own
valve closing mechanism with the pneumatic ratchet, support bracket and interconnecting
key assembly. Each such assembly is connected via air supply to the control unit which
may be common to all the mechanisms.
Electrical power is supplied to the electric actuator via a power supply module,
battery backup and control unit that serves to supply electrical power to the electrical
actuator thereby closing the valve spindle to the desired torque and turning off the actuator
after a pre programmed time.
The valve closing mechanisms are present as a precautionary measure and will not
usually affect operation of the gas supply system.
Initially during setting up, after the positioning and fixing the actuator and support
bracket assembly to the valve body and the connection of the outlet of the cylinder to the
downstream equipment the valve is opened by manipulation of the spindle using a suitable
tool temporarily engaged with the squared section of the valve spindle. In normal
operation the valve is unaffected by the closing mechanism. If however the detector senses
the presence of gas in the surroundings, the valve is operated to supply compressed air to
the actuator assembly via the air solenoid valve (switching mechanism) thereby effecting
closure of the valve of each chlorine cylinder . The system includes an alarm device to
draw attention to the fact that the valve closing mcchanism(s) have come into operation.
In the event of operation of the valve closing mechanisms, once the source of any
leak has been traced and remedied, each valve is then manually restored to the open
position by releasing the drive fittings from the squared spindle section and rotating the
spindle in the valve opening direction using a suitable tool. The support bracket/actuator
assemblies are then refitted to the spindles to bring the valve closing mechanisms back into
operation.
As outlined above, it will be seen that valve closure is affected in a particularly
simple manner without the need for action on the part of personnel. Moreover the valve
closing mechanism is of a simple design, can utilise both electric or pneumatic powered
sources, can be fabricated economically and is readily changed over from one cylinder to
another when cylinder replacement is necessary.
In the latter event, all that is necessary is to release the support bracket from the
cylinder valve as a unit by loosening the tightening wing nut.
While various embodiments of the present invention have been described above, it
should be understood that they have been presented by way of example only, and not by
way of limitation. It will be apparent to a person skilled in the relevant art that various
changes in form and detail can be made therein without departing from the spirit and scope
of the invention. Thus, the present invention should not be limited by any of the above
described exemplary embodiments.
The reference in this specification to any prior publication (or information derived
from it), or to any matter which is known, is not, and should not be taken as an
acknowledgment or admission or any form of suggestion that that prior publication (or
information derived from it) or known matter forms part of the common general
knowledge in the field of endeavour to which this specification relates.
Throughout this specification and the claims which follow, unless the context
requires otherwise, the word "comprise", and variations such as "comprises" and
"comprising", will be understood to imply the inclusion of a stated integer or step or group
of integers Or steps but not the exclusion of any other integer or step or group of integers
steps.