WO1999020872A1

WO1999020872A1 - Novel control system

Info

Publication number: WO1999020872A1
Application number: PCT/GB1998/002864
Authority: WO
Inventors: Timothy Mark Overfield; Michael Cumming
Original assignee: Timothy Mark Overfield; Michael Cumming
Priority date: 1997-10-17
Filing date: 1998-09-22
Publication date: 1999-04-29
Also published as: GB9721929D0; NO20001866D0; NO20001866L; EP1023523A1; AU9175398A

Abstract

A control system adapted for controlling hydro/mechanical tools in a selected environment, comprising a plurality of electronic components wherein at least one electronic component is sensitive to the selected environment, and at least one electronic component is substantially non-sensitive to the selected environment, wherein the system comprises dedicated means for protecting the at least one sensitive component from the selected environment such that the at least one sensitive component is in operative communication with the at least one non-sensitive component thereof.

Description

NOVEL CONTROL SYSTEM

The present invention relates to control system apparatus, components thereof, the use thereof, and a method for the manufacture thereof. Specifically the invention relates to control system apparatus comprising a protective housing, components thereof including the protective housing, the use thereof under hostile conditions and a method for the manufacture thereof.

Since the 1970's oil production has become a major industry, not least in Britain.

Early oil fields were in relatively shallow water which allowed the greater part of the production equipment to be fitted above water on platforms. Where equipment was installed sub-sea this was of simple construction that could be serviced by divers. Over the years this situation has changed.

There are three reasons for this:

1. The collapse of the oil price in 1985 has led to pressure to develop technologies that will result in significant long term cost reductions.

2. Oil fields are exploited in ever deeper waters as the larger and older fields in shallow water reach the end of their productive life.

3. Tightened Health and Safety legislation is increasing the cost of operation of conventional offshore structures in general and in particular diving operations associated with these structures.

The end result is that there is an increasing trend towards installing and decommissioning oil production equipment on the sea bed which can only be serviced by remotely operated submarines carrying specialised computer controlled tools.

This servicing work is carried out by sub-sea service companies working under contract to the oil majors who operate the oil fields. These service companies have a great deal of experience designing and operating the hydro/mechanical tools required for the various operations. In addition to this the servicing work requires a great deal of expertise in computer control skills together with specialist equipment in this area.

Existing computer control systems available on the market are based on bought in modules housed in large, strong, heavy containers at or close to atmospheric pressure. However this results in large, and heavy expensive systems that are cumbersome and not ideal for use.

Computer control systems typically comprise components including active and passive electronic components including a microprocessor, microcomputer or a micro-controller or some other control element mounted on printed wiring or circuit boards, timing or frequency generation components, pressure transducer valves installed for connection to hydro/mechanical tools and thereby to remotely operate these, in addition to any components required for video monitoring, illumination, provision of power supply for external items, digital and analogue sensors and serial data ports as an example only of the many possible components which it may be desired to incorporate for any given application or purpose. The size and sensitivity of such a control system to a given environment is dependent therefore on the nature and size of components. The size of the system is related to the size of components magnified to a degree dependent upon the nature and degree of hostility of the intended environment, by protective housing adapted to protect against conduct liquids or solids, high levels of contaminants or corrosive compounds, high levels of ambient pressure, high ambient temperature and the like.

Sensitive elements such as timing elements may survive in elevated pressure in environments up to about 10 bar atmospheric, without significant damage or becoming unreliable. However beyond these pressures the conventional packaging for such elements is insufficient to prevent substaining damage or unreliability.

Accordingly, there is a need for computer control systems of high quality suited to advanced applications such as sub-sea servicing or operations of hydro/mechanical tools whether for the oil industry or otherwise, which are of convenient size thereby improving access to hydro/mechanical tools, but nevertheless have an appropriate degree of protection to cope with the hostile conditions of the intended environment.

It should be appreciated that such control systems may be of advantage in any number of applications for control of hydro/mechanical equipment in hostile environments such as described above.

We have now surprisingly found that a novel control system may be provided to overcome the above mentioned disadvantages of known systems in admirable manner.

Accordingly, in its broadest aspect there is provided according to the present invention a control system adapted for controlling hydro/mechanical tools in a selected environment, comprising a plurality of electronic components wherein at least one electronic component is sensitive to the selected environment, and at least one electronic component is substantially non- sensitive to the selected environment, wherein the system comprises dedicated means for protecting the at least one sensitive component from the selected environment such that the at least one sensitive component is in operative communication with the at least one non-sensitive component thereof.

Reference herein to sensitive and non-sensitive components is to components the operation of which becomes impaired or distorted in any way by the selected environment.

The particular advantage of the apparatus of the invention derives from the recognition that a distinction may be made between sensitive and non- sensitive components of the control system whereby dedicated protecting means may be provided only for the sensitive components, together with means for ensuring operative communication of these with the remaining non-sensitive components. This significantly reduces the size of protective housing acquired or may even eliminate this totally, depending on the nature of the protective means employed.

It should be appreciated that the dedicated protecting means provided for the purposes of the at least one sensitive component may also by the nature of the provision thereof, provide protection for one or more non-sensitive components. Preferably therefore the protecting means is adapted with specifically to exclude at least the bulky non-sensitive components of a control system from protection. The distinction between bulky and non- bulky non-sensitive components should be made with reference to the individual case, wherein non-sensitive components which may be protected are those of small enough dimensions as not to compromise the advantages obtained by providing protecting means in dedicated form as hereinbefore defined. More preferably the apparatus of the invention comprises at least one sensitive component, at least one bulky non-sensitive component and optionally at least one non-bulky non-sensitive component, wherein dedicated protecting means provided for the sensitive component may also provide protection for the at least one, non-bulky, non-sensitive component but excludes from protection the at least one bulky non-sensitive component.

More preferably a non-bulky non-sensitive component is of similar order of magnitude to that of a sensitive component to be protected as hereinbefore defined.

The protective means envisaged include a dedicated protective housing, hereinafter a micro housing, comprised with non-sensitive components of the control system and any additional modules of the system as a unit apparatus. Alternatively protective means comprises a remote link for sensitive components to non-sensitive components and any additional modules of the control system, the remote link being such as to enable the positioning of the sensitive elements outside the boundary of the hostile environment but in operative communication with the non-sensitive components and any further modules of the control system located or adapted to be located within the hostile environment.

A remote link is provided between a sensitive component located outside the boundaries of the hostile environment and in operative communication with non-sensitive components, and additionally in operative communication with a similar sensitive component which is able to operate within the hostile environment, but subject to distortion or unreliability. Such remote link may be for transmission of a continuous timing signal or a non-continuous calibration signal. In the case of a non-continuous calibration signal, the control system of the present invention provides for improved accuracy and precision, since inaccurate internal or external timing signals may be calibrated or compensated by signals or constants transmitted via the remote link, whereby monitoring and recalibration enables the distorting effect to be compensated.

In a preferred embodiment of the invention the control system is adapted for use at high levels of ambient pressure. In this case, pressure sensitive components including timing or frequency elements, for example quartz crystals, ceramic resonators, atomic sources or monolithic oscillator systems, are comprised in a micro pressure vessel or comprised in a separate module located, optionally in a control centre, at atmospheric levels of ambient pressure or above sea level and in operative communication with the non- sensitive components and any further modules of the control system.

This embodiment of the present invention derives purely from the fact that the majority of components of a control system are pressure insensitive and it is in fact only a timing or frequency element which must be protected from high levels of ambient pressure.

It is a further particular advantage that the timing or frequency element is very small in comparison to the control system as a whole and correspondingly the micro-pressure vessel may be constructed with a very small internal volume. It is well known that the wall thickness of any vessel will be proportional to the internal volume thereof in order to withstand any given pressure without implosion or damage. Accordingly by minimising the internal volume required, it is possible to use a micro pressure vessel of relatively small dimensions.

Preferably the free space comprised as the internal volume of the micro pressure vessel is in the region of up to 1000 ml, preferably 0.1-500 ml, more preferably 0.5-50 ml, most preferably 1-30 ml whereby wall thickness may be in the region of 0.5-50 mm, for example 1-lOmm to withstand pressure in the region of up to 1000 bar a above atmospheric pressure. By this means the provision of dedicated protecting means for timing or frequency elements such as a quartz crystal or the like can provide a reduction in weight and volume of a control system of the order of up to up to at least 50 kg compared with systems having non-dedicated protecting means.

A micro pressure vessel may be constructed of any suitable material adapted to withstand the envisaged pressures. It is of particular advantage that the provision of a micro-pressure vessel or remote link with a pressure sensitive component enables freedom of choice of materials for construction of other modules or containing walls of control systems as hereinbefore defined. Materials for construction of containing walls or the micro pressure vessel of a control system as hereinbefore defined are suitably adapted to withstand any hostile conditions envisaged and preferably include any metals, alloys, reinforced composites or synthetic polymeric structures and the like for example . In particular aluminium, carbon fibre, titanium, ceramic, or steel is preferred.

A remote link between a timing or frequency element or other frequency calibration system located outside the hostile environment with a control system located within a hostile environment is typically comprised of appropriate electrical, fibre or sonic links using cables or emitting frequencies in the range of 1 Hz- 100 kHz or the like adapted to transmit the necessary signals, and which are substantially pressure insensitive.

Preferably a control system for use in humid, moist or the like environment comprises an anhydrous medium adapted to prevent ingress of moisture with detrimental effect on the control system and its operation. Any known medium may be employed, for example the control system may comprise oil or like fluid.

A control system requiring protection from moisture or humidity or the like as a hostile environment, preferably comprises an anhydrous medium as hereinbefore defined which is maintained at slight overpressure above that of the surrounding environment. This is a particular advantage of the invention whereby the control system may be constructed to lower constraints in terms of sealing against entry of moisture, the overpressure of an anhydrous medium serving as an effective seal against ingress of moisture or the like.

Preferably therefore the control system is maintained at an internal pressure of the order of 1-10 psi above the external pressure of the hostile environment, for example in the order of 2-5 psi.

The anhydrous medium is suitably substantially non-compressible and non- conductive and may be in the form of a solid, liquid or gel and is introduced in manner to fill all interstices and voids of the system comprised within containing walls.

A control system may comprise any known hydraulic system suitable for operation of external hydro/mechanical equipment, preferably a pressure transducer may be installed internally in the control system and ported externally for connection to external equipment.

It is a further advantage that any control system may be constructed in manner adapted for easy disassembly thereof for replacement or customising of component parts. Similarly any software comprised in the system may be easily modified, edited or upgraded without the need for physical disassembly, modification, replacement or alteration of parts. A control system comprising a remote link to the timing or frequency element may in a further advantage be adapted for modifying remote software to customise the actions, scaling of signals and the like without the need to reinstall the software.

The control system of the invention may be used with any suitable software as known in the art adapted for the particular application envisaged.

In a further aspect of the invention there is provided novel component parts of the control system of the invention, specifically dedicated protection means as hereinbefore defined comprising a micro vessel or a remote link as hereinbefore defined.

In a further aspect of the invention there is provided the use of a control system as hereinbefore defined to monitor, control, instrument or communicate information or data or to store information or data or protect systems in the control of hydro/mechanical tools in any desired operation to be conducted in a hostile environment as hereinbefore defined. Preferred applications include sub-sea exploration for mineral recovery, salvaging for scientific purposes, maintenance decommissioning or repair of subterraneous or, sub-sea applications such as in transport or storage of resources such as oil, water and the like in reservoirs or pipelines, for electronic monitoring of remote sites, operation of chemical plants in which airborne contaminants such as carbon dust can be damaging to components for control systems hereinbefore defined, and the like.

In a further aspect of the invention there is provided a method for manufacture of a control system as hereinbefore defined comprising providing dedicated protecting means as hereinbefore defined in manner adapted to be located within or connected to the containing unit of any control system.

The invention is now illustrated with respect to the following figures wherein:

Figure 1 and 2 illustrate a cross-section through a micro-pressure vessel of the invention as hereinbefore defined.

Figure 3 illustrates a control system adapted to contain a micro-pressure vessel of Figure 1.

Figure 4 illustrates a control system adapted to comprise a remote link to a pressure sensitive component.

In Figure 1 is shown a micro-pressure vessel comprising a pressure resistant truncated or symmetrical capsule (1) comprising cylindrical walls (2) and one or both pressure resistant ends (3). The capsule comprises pressure sensitive component (4) with connection wires (5) passing from inside to outside of the capsule (1), to provide a connection with non sensitive components and any further modules of a control system. The capsule is suitably provided with a pressure resistant seal (6). The seal (6) and additional pressure resistant spacers (7) may be employed to reduce the internal free space (8) of capsule (1), to less than the total internal volume thereof. The free space may be occupied by air or by a less compressible medium such as oil or the like.

In Figure 2 is shown an alternative micro-pressure vessel comprising cylindrical walls (2) with pressure resistant seals (6) at both ends thereof. Connection wires (5) may be positioned passing through one or both seals (6) as shown.

In Figure 3 is shown a control system comprising housing (10) sealing the contents thereof from the hostile environment (C). The contents of the housing are maintained in controlled environment (B) which is at a similar elevated ambient pressure to that of hostile environment (C), or may be at slight overpressure to prevent entry of moisture and the like. A plug- in unit (11) comprises micro-pressure vessel (12). The contents are maintained under controlled environment (A) which may be similar to that of environment (B) although separate therefrom. The contents of micro- pressure vessel (12) are maintained at atmospheric pressure as hereinbefore described. The control system may comprise any additional non-sensitive components and further modules as desired, such as inputs and outputs (13) for lights, cameras and the like, inputs for data such as digital and analogue input (14), power input (15) and the like. The unit (10) comprises porting for hydraulic interconnections (16).

A computer control panel and signal conditioning unit (17) comprises non- sensitive elements which are maintained at conditions (B). Nevertheless certain non-sensitive elements may be incorporated in the micro-pressure vessel (12), typically being non-bulky non-sensitive elements, without loss of the advantages of the invention. Such non-bulky non-sensitive components may comprise, but are not limited to, resistors, capacitors, relays, semi-conductor devices or any other active or passive components. In this case the micro-pressure vessel (12) may be located directly as a plug-in unit on the external or internal wall of unit (17), without the provision of surrounding plug-in unit (11).

In Figure 4 is shown an alternative embodiment of the invention comprising pressure sensitive component (4), optionally located in plug-in unit (11), maintained at atmospheric conditions. The component is connected via connecting wires (5) to electronic system (21) (or is part of electronic system (21) which transmits the signal via remote link (20) to a control system (10) which is as hereinbefore defined located in the hostile environment (C).

Alternatively the electronic system (21) receives an inaccurate signal via remoted link 20 and compares with the accurate signal from pressure sensitive component (4). The difference or calibration signal is transmitted back to control system (10) via remote links (20) on a continuous or non continuous basis. In this case the control system omits any form of micro- pressure vessel and is maintained entirely under environment (C) or optionally under environment (A) and/or (B) as desired.

Further advantages of the invention will be apparent from the foregoing.

Claims

1. A control system adapted for controlling hydro/mechanical tools in a selected environment, comprising a plurality of electronic components wherein at least one electronic component is sensitive to the selected environment, and at least one electronic component is substantially non- sensitive to the selected environment, wherein the system comprises dedicated means for protecting the at least one sensitive component from the selected environment such that the at least one sensitive component is in operative communication with the at least one non-sensitive component thereof.

2. A control system as claimed in Claim 1 in which the protecting means is adapted specifically to exclude at least the bulky non-sensitive components of a control system from protection.

3. A control system as claimed in Claim 1 or 2 in which the apparatus of the invention comprises at least one sensitive component, at least one bulky non-sensitive component and optionally at least one non-bulky non-sensitive component wherein dedicated protecting means provided for the sensitive component may also provide protection for the at least one non-bulky, non- sensitive component but excludes from protection the at least one bulky non- sensitive component.

4. A control system as claimed in Claim 3 in which a non-bulky non- sensitive component is of similar order of size magnitude to that of a sensitive component to be protected as hereinbefore defined.

5. A control system was claimed in any of Claims 1 to 4 in which the protective means include a micro housing.

6. A control system was claimed in any of Claims 1 to 4 wherein protective means comprises a remote link for sensitive components to non- sensitive components and any additional modules of the control system.

7. A control system as claimed in Claim 6 wherein a remote link is provided between a sensitive component located outside the boundaries of the hostile environment and in operative communication with non-sensitive components, and additionally in operative communication with a similar sensitive component which is able to operate within the hostile environment, but subject to distortion or unreliability.

8. A control system as claimed in Claim 7 wherein a non-continuous calibration signal is transmitted along the remote link.

9. A control system as claimed in any of Claims 1 to 8 wherein the control system is adapted for use at high levels of ambient pressure and wherein pressure sensitive components including timing or frequency elements are comprised in a micro pressure vessel.

10. A control system as claimed in Claim 9 wherein the free space comprised as the internal volume of the micro pressure vessel is in the region ofup to 1000 mi┬¼

l l . A control system as claimed in Claims 9 or 10 wherein wall thickness is in the region of 0.5-50 mm.

12. A control system as claimed in Claims 1 to 11 comprising an anhydrous medium adapted to prevent ingress of moisture with detrimental effect on the control system and its operation.

13. A control system as claimed in Claim 12 wherein the anhydrous medium is maintained at a slight overpressure above that of the surrounding environment, preferably of the order of 1-10 psi above the external pressure of the hostile environment.

14. A control system as claimed in any of Claims 1 to 13 comprising a pressure transducer installed internally in the control system and ported externally for connection for external equipment.

15. A control system as claimed in any of Claims 6 to 8 adapted for modifying remote software to customise the actions, scaling of signals and the like without the need to reinstall the software.

16. Dedicated protection means as hereinbefore defined comprising a micro vessel or a remote link as hereinbefore defined.

17. The use of a control system as hereinbefore defined for sub-sea exploration for mineral recovery, salvaging for scientific purposes, maintenance decommissioning or repair of subterraneous or, sub-sea applications such as in transport or storage of resources such as oil, water and the like in reservoirs or pipelines, for electronic monitoring of remote sites, operation of chemical plants in which airbourne contaminants such as carbon dust can be damaging to components for control systems hereinbefore defined, and the like.

18. A method for manufacture of a control system as hereinbefore defined comprising providing dedicated protecting means as hereinbefore defined in manner adapted to be located within or connected to the containing unit of any control system.