GB2184581A

GB2184581A - Remote control system

Info

Publication number: GB2184581A
Application number: GB08531802A
Authority: GB
Inventors: Colin Dougal Mcewen
Original assignee: STC PLC
Current assignee: STC PLC
Priority date: 1985-12-24
Filing date: 1985-12-24
Publication date: 1987-06-24
Also published as: GB2184581B; GB8531802D0

Abstract

In a shut off valve control system for an oil or gas platform, the valve (13) is operated by command signals from a control station (14) transmitted on a guided microwave carrier via the pipe (12). <IMAGE>

Description

SPECIFICATION Remote control system This invention relates to remote control systems e.g. for pipelines. There is a need to communicate control signals from marine oil/gas platforms to shut-offvaluesin pipelineswhich carry oil or gas from the platform to a shore station orto a collection point.

At presentthese values are controlled via a flexible wirethat is laid inside the pipe. If this wire is broken the valve cannot then beturned off resulting in a potentially hazardous situation particularly as breakage ofthewire may not become apparent until operation of the valve is required in an emergency.

Also it is not possible to effect a repair without dismantling the pipe and interrupting the fluid flow.

The object ofthe present invention isto minimise or to overcome this disadvantage.

According to one aspect of the invention there is provided a remote control system, the system comprising a control station, and one or more receiver stations each coupled to the control station via a pipe ortube having waveguiding properties, and means associated with the control station fortransmitting guided microwave signals via the pipes or tubes to the receiver stations.

According to another aspect ofthe invention there is provided a pipeline remote control system for a marine oil orgas platform, the system including a control station disposed on the platform, a microwave transmitter associated with the control station whereby the station is coupled to a gas or oil pipe providing a waveguide forthe microwave transmission, a shut off valve arranged to control a fluidflowthrough the pipe, and a microwave receiver and valve actuator associated with said valve whereby, in use, the valve is actuated in response to signals transmitted via the pipe from the control station.

An embodiment oftheinvention will now be described with reference to the accompanying d rawings in which: Fig. lisa schematic diagram of an oil/gas platform remote control system.

Fig.2 is a sectional view of the transmitter end of the pipeline ofthe system of Fig. 1; and Fig. 3 isis a sectional view ofthe receiver end of the pipeline.

Referring to Fig. 1, an oil/gas marine platform 11 is coupled to a shore station or a collection point (not shown);via a pipeline 12. This pipeline includes a shut offvalvel3typicallysituated about 600 m from the platform 11. A control station 14 disposed on the platform 11 includes a microwave generator 15 whereby guided microwave signals are transmitted via the pipe 12to a receiver 16 and an associated actuator 17 adjacentthe valve 13. Preferablytransmis sion is effected in the Ho1 mode as this mode exhibits a low toss in a similar guide.Further, this and certain other modes do not requirethe waveguidewalls of a metal waveg uidei to be perfectly conductive and hence it is not necessary to line a steel pipe with a highly conductive metal e.g. copper. Moreover it is not necessaryforthe pipe to have any electrical conductivity: it must merely havewaveguiding properties at microwave frequencies. Thus, for example, a dielectric pipe may be employed having a high dielectric constant inner surface and a low dielectric constant outer surface. The propagation is not effected significantly by bends in the pipe provided that the bend radius is large compared with the pipe radius.

The frequency of transmission is chosen such that the pipe contents, e.g. natural gas, have a low absorption. Since the transmission is guided there are no frequency restrictions improved by broadcasting regulations and hence one or more suitable frequencies,typically in the range 100 MHzto 100 GHz,can be used. Generallyweusea higherfrequencythanthe fundamentalfrequencyofthepipesothatthe waveguide is heavily overmoded. This is not a disadvantage in the present application as the transmission at high bit rates of large amounts of data is not required. Also, asthetransmission path is relatively short, a degree of power loss that would be totally unacceptable for longhand waveguide practice can be tolerated.

The microwave signal may be modulated to convey command information via the receiver 16to the actuator 17 to operate the valve 13. The system may be rendered fail safe by adapting the receiver 16 and actuator 17 to close the valve 13 in the event of an interruption to the microwave signal.

In some applications the power for actuation of the valve may be derived from the microwave energy. In such an arrangementthe receiver includes a rectifier coupled to a storage battery. Because the wave is guided, as opposed to free space propagation, the inverse square law does not apply and the efficiency of powertransfer is thus high. This enables worthwhile quantities of power to be transmitted in this way.

Fig. 2 illustrates the method of launching the microwave signal into the pipe. The pipe 12 has an opening 21 fitted with an insulating gland 22 through which a conductive probe 23 is inserted. The probe is coupled to the microwave transmitter. The position of the probe in the pipe is adjusted to provide optical coupling ofthe desired mode or modes of propagation.

Coupling of the receiverto the pipe can be effected via a similar probe or, as shown in Fig. 3, via a conductor 31 mounted on a dielectric slab 32 affixed to the inner surface of the pipe 12.

In afurtherapplicationthecontroil4and valve 13 may both have an associated transistor whereby signals may be transmitted back to the control 14 indicative of the open or closed position of the valve.

Whilst the foregoing description describes the operation of the system with reference to oil and gas pipelines it will be appreciated that it is not so limited.

Thus similar arrangements may be employed in remote control applications in e.g. mines and tunnels.

1. A remote control system, the system compris ing á control station, and one or more receiver stations

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Remote control system This invention relates to remote control systems e.g. for pipelines. There is a need to communicate control signals from marine oil/gas platforms to shut-offvaluesin pipelineswhich carry oil or gas from the platform to a shore station orto a collection point. At presentthese values are controlled via a flexible wirethat is laid inside the pipe. If this wire is broken the valve cannot then beturned off resulting in a potentially hazardous situation particularly as breakage ofthewire may not become apparent until operation of the valve is required in an emergency. Also it is not possible to effect a repair without dismantling the pipe and interrupting the fluid flow. The object ofthe present invention isto minimise or to overcome this disadvantage. According to one aspect of the invention there is provided a remote control system, the system comprising a control station, and one or more receiver stations each coupled to the control station via a pipe ortube having waveguiding properties, and means associated with the control station fortransmitting guided microwave signals via the pipes or tubes to the receiver stations. According to another aspect ofthe invention there is provided a pipeline remote control system for a marine oil orgas platform, the system including a control station disposed on the platform, a microwave transmitter associated with the control station whereby the station is coupled to a gas or oil pipe providing a waveguide forthe microwave transmission, a shut off valve arranged to control a fluidflowthrough the pipe, and a microwave receiver and valve actuator associated with said valve whereby, in use, the valve is actuated in response to signals transmitted via the pipe from the control station. An embodiment oftheinvention will now be described with reference to the accompanying d rawings in which: Fig. lisa schematic diagram of an oil/gas platform remote control system. Fig.2 is a sectional view of the transmitter end of the pipeline ofthe system of Fig. 1; and Fig. 3 isis a sectional view ofthe receiver end of the pipeline. Referring to Fig. 1, an oil/gas marine platform 11 is coupled to a shore station or a collection point (not shown);via a pipeline 12. This pipeline includes a shut offvalvel3typicallysituated about 600 m from the platform 11. A control station 14 disposed on the platform 11 includes a microwave generator 15 whereby guided microwave signals are transmitted via the pipe 12to a receiver 16 and an associated actuator 17 adjacentthe valve 13. Preferablytransmis sion is effected in the Ho1 mode as this mode exhibits a low toss in a similar guide.Further, this and certain other modes do not requirethe waveguidewalls of a metal waveg uidei to be perfectly conductive and hence it is not necessary to line a steel pipe with a highly conductive metal e.g. copper. Moreover it is not necessaryforthe pipe to have any electrical conductivity: it must merely havewaveguiding properties at microwave frequencies. Thus, for example, a dielectric pipe may be employed having a high dielectric constant inner surface and a low dielectric constant outer surface. The propagation is not effected significantly by bends in the pipe provided that the bend radius is large compared with the pipe radius. The frequency of transmission is chosen such that the pipe contents, e.g. natural gas, have a low absorption. Since the transmission is guided there are no frequency restrictions improved by broadcasting regulations and hence one or more suitable frequencies,typically in the range 100 MHzto 100 GHz,can be used. Generallyweusea higherfrequencythanthe fundamentalfrequencyofthepipesothatthe waveguide is heavily overmoded. This is not a disadvantage in the present application as the transmission at high bit rates of large amounts of data is not required. Also, asthetransmission path is relatively short, a degree of power loss that would be totally unacceptable for longhand waveguide practice can be tolerated. The microwave signal may be modulated to convey command information via the receiver 16to the actuator 17 to operate the valve 13. The system may be rendered fail safe by adapting the receiver 16 and actuator 17 to close the valve 13 in the event of an interruption to the microwave signal. In some applications the power for actuation of the valve may be derived from the microwave energy. In such an arrangementthe receiver includes a rectifier coupled to a storage battery. Because the wave is guided, as opposed to free space propagation, the inverse square law does not apply and the efficiency of powertransfer is thus high. This enables worthwhile quantities of power to be transmitted in this way. Fig. 2 illustrates the method of launching the microwave signal into the pipe. The pipe 12 has an opening 21 fitted with an insulating gland 22 through which a conductive probe 23 is inserted. The probe is coupled to the microwave transmitter. The position of the probe in the pipe is adjusted to provide optical coupling ofthe desired mode or modes of propagation. Coupling of the receiverto the pipe can be effected via a similar probe or, as shown in Fig. 3, via a conductor 31 mounted on a dielectric slab 32 affixed to the inner surface of the pipe 12. In afurtherapplicationthecontroil4and valve 13 may both have an associated transistor whereby signals may be transmitted back to the control 14 indicative of the open or closed position of the valve. Whilst the foregoing description describes the operation of the system with reference to oil and gas pipelines it will be appreciated that it is not so limited. Thus similar arrangements may be employed in remote control applications in e.g. mines and tunnels. CLAIMS

1. A remote control system, the system compris ing á control station, and one or more receiver stations each coupled to the control station via a pipe or tube having waveguiding properties, and means associatedwith the control station for transmitting guided microwave signals via the pipes or tubes to the receiver stations.

2. Asystem as claimed in claim 1, wherein said pipe ortube comprises a gas or oil pipeline.

3. A system as claimed in claim 1 or 2, wherein said receiver incorporates energy storage means whereby power derived from the transmitted microwave signal is stored.

4. A pipeline remote control system for a marine oil or gas platform, the system including a control station disposed on the platform, a microwave transmitterassociated with the control station whereby the station is coupled to a gas or oil pipe providing a waveguideforthe microwave transmission, a shut off valve arranged to control a fluid flowthrough the pipe, and a microwave receiver and valve actuator associated with said valve whereby, in use, the valve is actuated in response to signals transmitted via the pipefromthe control station.

5. A remote control system as claimed in claim 4, wherein said actuator is adapted to close the valve in the absence of a microwave transmission.

6. A remote control system substantially as described herein with reference to and as shown in the accompanying drawings.