GB2266560A

GB2266560A - Air motor driven valve actuation system.

Info

Publication number: GB2266560A
Application number: GB9208925A
Authority: GB
Inventors: William Stuart Deeley; Jeffrey Sewell
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1992-04-24
Filing date: 1992-04-24
Publication date: 1993-11-03
Anticipated expiration: 2012-04-24
Also published as: GB2266560B; GB9208925D0

Abstract

A remotely operated system for manipulating the valve of a gas container (27, Fig. 2) comprises an air motor 1 having a drive shaft, on which a flange 5 is keyed and adapted for engagement with the valve handwheel 6 of the gas container, there being a frame 3, removable from the container, for supporting the air motor 1. A control panel (23, Fig. 2) is located remotely from the gas container (27), for controlling supply of compressed air to the air motor to selectively rotate the shaft thereof. <IMAGE>

Description

System The present invention relates to a valve manipulation system, especially to an automatic valve manipulation system for use on gas containers. Many important chemical reactants, for use in the synthesis of other, more complex chemical compounds, are gaseous at normal pressure. Such gases need to be stored and transported as liquids under high pressures. Many such gases, e.g. chlorine, are hazardous to the health of operators. In the event of a major release of such a hazardous gas from its container, the only conventional method of closing and securing the escape of gas is by manual means. This method clearly involves considerable risks to the workers concerned, even if they are protected by suitable protective clothing.

In U.S. Patent 4527715, there is described a remotely actuated system for opening or closing the valves on gas cylinders. The apparatus in question, for the remote actuation of a valve, having a manually operable valve handle on a gas cylinder, comprises shaft means for engaging the valve handle and selectively moving the valve between its closed position and its open position; pneumatic means connected to the shaft means for actuating the latter, means for being removably connected to the cylinder to support the shaft means and the pneumatic means; means located remotely from the cylinder for controlling the operation of the pneumatic means; a source of compressed gas; and initiation means, included in the controlling means, for selectively directing flow of the compressed gas, under pressure, to the pneumatic means for rotating the shaft means in the direction of closing the valve, or rotating the shaft means in the direction of opening the valve.

This known apparatus has the disadvantage that the particular pneumatic means, which is specifically described in U.S. 4527715, consists of a cylinder assembly comprising a cylinder containing a slidable piston. A chain drive extends externally of the cylinder engaged with teeth mounted on shaft means, as it passes through the assembly. As a result of this design, the closing force applied to the valve is not limited by the pressure of the compressed gas, rather by the said gearing system. Consequently, excess torque can be easily applied to the valve, with consequent mechanical damage to the valve assembly.

In addition, a remotely actuated system for opening or closing valves on mini-bulk chlorine gas containers has been marketed in Great Britain under the trade name "Chlorguard". This device is heavy and cumbersome, severely restricting access around each container.

We have now developed a light and compact system which overcomes the disadvantages of known systems and which, in particular, applies a specific torque to the valve assembly, by using an air motor to provide the motive force required to operate the valve mechanism. It also offers a simple mounting system to the mini-bulk cylinder and, with use of the counter balance support, removes the valve assembly from the working area when it is not required.

Accordingly, the present invention provides a remotely operating system for manipulating the valve of a gas container comprising a) an air motor having a drive shaft; b) flange means, keyed onto the drive shaft of the air motor, and adapted for engagement with the valve of the gas container; c) means, removable from the container, for supporting the air motor; d) means, located remotely from the gas container, for controlling operation of the air motor; e) a source of compressed gas; and f) actuation means, associated with means d), for selective actuation of the supply of the compressed gas to the air motor, in order to rotate the shaft of the air motor.

In one preferred embodiment, one or more, preferably four dowels are arranged, preferably screwed into the flange means. These dowels are used to engage into one or more corresponding holes of a conventional valve handwheel. This assembly is preferably supported by a rigid, e.g. mild steel frame. This frame is conveniently secured to the gas container by utilizing some or all of the studs which are conventionally present on the container in order to protect the isolating valves during transport of the container. Such a preferred assembly enables the frame to be located accurately on to the gas-container. The flange on the air motor can readily be rotated so that the dowels are aligned with the holes in the handwheel.

The total weight of a typical frame is about 5kg. Preferably, the frame is supported by a retractable spring balance. When the frame is not in use, the spring balance supports the frame above the gas container. When the frame is in use, the spring balance reduces to a minimum the mechanical stress caused by the frame assembly on the studs. The studs can safely support the frame in the event of failure of the spring balance.

The air feed to the air motor is preferably effected via a metallic flexible hosing, which is preferably both crimp and fire resistant. Preferably, the main air feed line is constructed of stainless steel.

An air motor provides the motive force necessary to rotate the handwheel on the gas container valve. The motor is sized to generate the necessary torque to open or close the valve. Clean, well lubricated and pressure controlled air is preferably fed normally from a plant air main or, if circumstances dictate, from a standby air bottle.

A suitable air motor for use in a valve-closure system according to the present system is a non-reversible air motor.

An air motor control means, located remotely from the gas container, is conveniently in the form of a control panel. This panel may house relay/pneumatic control circuits necessary to provide air signals to operate the air motor. To take account of any mains air failure, a pressure switch may be provided which, on activation, can transfer air supply to a standby air bottle.

The control means preferably also comprises local emergency manual override systems, remote indicators showing the open/closed state of the valve, back-up battery system operation means and automatic close-down operation means for the valve, under preselected emergency conditions.

Preferably, means are also provided which are remotely located from the gas container and which serve to remove the valve manipulation system of the present invention, from an area adjacent to the valve, and to store it at the remote location.

One embodiment of the system in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a section through a valve manipulation device; and Figure 2 is a schematic elevation view of the control panel showing external connections.

Referring to the drawings, firstly to Figure 1, the valve manipulation device shown has an air motor 1, having an air motor exhaust 2. The air motor 1 is supported on a support frame 3. Dowels 4 on the keyed drive flange 5 engage with holes in the handwheel 6 of the valve. Figure 1 also shows the valve body 7, a stud 8 and a dish end 9 of a conventional chlorine drum.

Figure 2 shows the instrument air main isolation valve 10 which is conveniently located on a pipebridge adjacent to the chlorine drum 27. Pressure gauge 11 should preferably read approximately 6 bar. g if instrument air is available. Gauge 11 is conveniently located in the drum bay. Valve 15, regulator valve 16 and lubricator 17 provide adjustment controls to ensure that the downstream pressure gauge 12 registers the desired pressure, preferably about 80 p.s.i. of lubricated air. Valve 18 regulates the supply of air from the standby air bottle 21, and valve 18 is adjusted so that gauge 14 reads the desired pressure, conveniently about 100 p.s.i. Valve 21 and regulator valve 20 are adjustable to control the downstream pressure, preferably about 80 p.s.i., which is measured by local gauge 13.

Control panel 23 comprises emergency stop buttons, closure buttons for the respective valves of four cylinders in a typical bank of four gas cylinders, and over-ride switches for chlorine escape alarms and for low-pressure of standby air bottle. Spring balance 24, metallic hose 25, metal wire support 26 for the frame, chlorine drum 27 with its pig-tail 28 and air motor 29 are also indicated in Figure 2.

In the operation of the system according to the present invention, the air supply is set up by opening valve 10 and ensuring that gauge 11 reads about 6 bar. g. Before opening valve 15, regulator valve 16 is rendered free of any spring loading. It is ensured that lubricator 17 has the prescribed volume of oil in its reservoir. Valve 15 is opened. Regulator valve 16 is adapted to self-vent to protect itself, when closed. Regulator valve 16 is adjusted so that the downstream pressure gauge 12 reads about 80 p.s.i. and the setting is locked by applying e.g. a snap action lock. Valve 18 on bottle 21 is opened, so that guage 14 reads about 100 p.s.i. It is ensured that lubricator 24 has the prescribed level of oil in its - reservoir.- Regulator 20 is freed of-any spring loading. Valve 21-is opened. Regulator 20 is adjusted so that the local downstream guage 13 reads about 80 p.s.i. At this point air is then available to the control panel and can be used to operate the air motor 29.

Claims

1. A remotely operating system for manipulating the valve of a gas container comprising a) an air motor having a drive shaft; b) flange means, keyed onto the draft shaft of the air motor, and adapted for engagement with the valve of the gas container, c) means, removable from the container, for supporting the air motor d) means, located remotely from the gas container, for controlling operation of the air motor; e) a source of compressed air; and f) actuation means, associated with means d), for selective actuation of the supply of compressed air to the air motor, in order to rotate the shaft of the air motor.

2. A system according to claim 1 in which one or more dowels, for engagement into the corresponding holes of a handwheel of the valve, are arranged in the flange means.

3. A system according to claim 1 or 2 in which the air motor removable support means is a mild steel frame.

4. A system according to any of the preceding claims in which the air motor removable support means is secured to the gas container by using some or all of the studs which are conventionally present on the container for the protection of isolating valves.

5. A system according to any of the preceding claims in which the air motor removable support means is itself supported by a retractable spring balance.

6. A system according to any of the preceding claims in which air feed to the air motor is effected by means of a metallic flexible hosing.

7. A system according to any of the preceding claims in which the air motor control means is in the form of a control panel.

8. A system according to claim 7 in which the control panel houses relay/pneumatic control circuits necessary to provide air signals to operate the air motor.

9. A system according to any of the preceding claims in which means are provided which are remotely located from the gas container and which serve to remove the valve manipulation system from an area adjacent to the valve, and to store it at the remote location.