GB2470980A

GB2470980A - Control of tools and equipment in an explosive environment

Info

Publication number: GB2470980A
Application number: GB1006190A
Authority: GB
Inventors: Torn Lyngdal
Original assignee: Beerenberg Corp AS
Current assignee: Beerenberg Corp AS
Priority date: 2009-04-15
Filing date: 2010-04-14
Publication date: 2010-12-15
Anticipated expiration: 2030-04-14
Also published as: GB2470980B; DK201000311A; NO329264B1; NO20091456L; GB201006190D0; DK179232B1; GB201006192D0

Abstract

A device for operation, control and surveillance of electrical and pneumatic tools and equipment in or adjacent to explosive areas comprises: a power inlet 130; power outputs 105; gas detector outputs 104; high pressure air inlets 103 and outputs 101; alarm devices 100,106; and a programmable control unit 108 configured to cut high pressure air supply for the high pressure air outlets 101 and to cut power supply to the power outputs 105. Gas detectors can be set for a 10% LEL and the high pressure air output and the current outputs cut off at threshold values above this level. The alarm can be acoustic and visual and the device state can be displayed on display 107,. Solenoids 102, can close the high pressure air outlets. The controller 108 can be housed in a pressurized closed chamber integrated with the device in a cabinet (fig 2,250) fitted with wheels 109, and the outputs meet requirements for use in an explosive environment.

Description

Title: Device, system and method for operation, control and monitoring tools and equipment in and adjacent to explosive hazardous areas.

Technical Field

[0001] Device adapted for secure operation, control and surveillance of tools and equipment in and adjacent to explosive areas, as well as an arrangement and a method for the same.

Background Art

[0002] Many areas where installation work and maintenance work are carried out are in or adjacent to explosive areas. Strict rules govern use of tools and equipment which are powered by electricity or compressed air within such areas. Not only does current supply and pressurized air supply in itself constitute a risk in such areas, heat and sparking due to work may also occur. Cabling equipment and contact equipment shall be certified according to the explosive environment in which it is operative. Further, it is a requirement that he or she, or those who work in such areas is alerted if the danger of explosion is above a given lower limit. LEL (Lower Explosive Limit). Such explosive areas are often referred to as Ex environments and equipment for use in such areas is often referred to as Ex certified following sudden norms or standards.

[0003] It shall in particular be mentioned that strict rules regulate use of equipment for work on oil installations due among others to the danger of having hydrocarbon gases that rises to explosive levels where work with electrical or pneumatic tools are in use, A problem with outdoor work on an installation may be caused by change of wind direction, so that explosive gases and dust is blown in the direction of the area where the work is carried out.

[0004] He, she or those who operate tools and equipment in such explosive surroundings will normally be equipped with gas detectors carried on their wrist. If this gas detector is triggered it will trig an alarm device which is supposed to alert he, she or those who operates tools, Furthermore one may additionally have a person which has the superintendence of the area in which work will be carried out, this person will, if being aware of it, cut air and electrical supply to equipment that is used.

[0005] There are numerous disadvantages related to the use of such a locally carried gas detector, the person carrying the detector may be unaware of any alarm due to noise from tools. Further, explosive danger may have reached the limit value locally to the person carrying the detector, and furthermore it may take some time before he or she manages to switch of tools and the supply to the tools.

[00061 It is known from US 5828307 a house for housing electrical equipment so as to facilitate use of such equipment at petroleum refineries where combustible gasses are present. The design provides a housing which is gas tight, except for an open from which provides a user access to the equipment and which simultaneously provides sufficient ventilation to the equipment in the housing. A gas monitor monitors the small opening in the housing and the monitor provides automatic shut off of power supply to the equipment in the housing upon detection of dangerous concentrations of combustible gasses which enters the opening of the housing.

[0007] From WO 20071 22296 Al it is further known a system for control of power, water or supply of gas in emergency situations and under energy saving conditions. The system comprises one or more detectors so as to provide different states of a surveillance area, it comprises a control unit as well as means for control of power, water or supply of gas to equipment.

[0008] It is an object according to the present invention to remedy the indicated problems above related to security and warning when working in or adjacent to explosive areas.

Summary of the invention

[0009] According to the present invention said problems are solved by a device adapted for operation, control and monitoring of tools and equipment in or adjacent to explosive environment, the device comprises: an input adapted for power supply; one or more power outputs approved for operation in explosive environments; one or more outputs for gas detectors, where the outputs meets requirements to equipment for use in explosive environment; one or more high pressure air inlet devices as well as on or more high pressure air outlets; at least one programmable control unit configured to shut off high pressure to the one or more high pressure outputs and to shut off power supply to the one or more power supply outputs, and one or more alarm devices.

[00101 The present invention also relates to a system for use of a device as indicated above. Where the system for operation and control of he tool and equipment comprises: said device above; one or more gas detectors adapted for connection to the outputs of the gas detectors; a cabinet adapted to hoLise the device, where the cabinet is provided with wheels and fastening ears.

[00111 Other advantageous features according to the present invention will become apparent from the accompanying independent and dependent claims.

Brief description of the drawings

[0012] The present invention will now be described in closer detail with support from the accompanying drawings, [0013] Fig. 1 shows a sketch of the principle of a device and an arrangement according to the present invention, [0014] Fig 2 shows a device according to the present invention in closer detail from three sides, and [0015] Fig. 3 shows an interlocking procedure for start up of the present device.

Detailed description of the invention

[0016] In the following a detailed description of the present invention will be disclosed with support in the accompanying drawings.

[0017] It shall be understood that by explosive environment, any area open or closed where danger of explosion may occur as a consequence of leakage or diffusion of explosive gases or dust, Further for simplicity, harmful gases is also included in the same definition if the contrary is not explicit disclosed.

[00181 Tool comprises air driven and electrically driven tools, but also equipment such as working light and any other equipment which is considered to be connected a device or an arrangement according to the present invention.

[00191 Alarm devices do not include the means that is trigging alarm signals, as it is meant devices which will render an active signal if an alarm is trigged as a consequence of threshold values being exceeded. Alarm signals will normally be trigged by one or more detectors where one or more predetermined threshold values are exceeded, e.g. where LEL is over 10%. The alarm devices include acoustic and visual signals. Typically an alarm device will comprise a siren which is certified according to given requirements to safety against explosion, as well as one or more lights which will light either constant or flashing and which satisfies given requirement to safety against explosion, further one may also have status information indicated on a displaying means which indicates an alarm signal.

[00201 Bu gas detector it is meant any detector which is adapted to sense particular gases and dust. The detector may be preset to deliver a trigging signal for an alarm at particular levels, or it may be programmable so that alarm levels can be configured based on requirements. One may also have sensors which produce one or more continuous signals indicating a state, such as concentration of dust or explosive gases. A continuous measurement may utilize a programmable or fixed unit which is programmed to execute a particular alarm interlocking as a response to received signals. It shall also be understood that gas detector can comprise a combination of different types of detectors or sensors, such as temperature or pressure detectors or sensors.

[00211 One or more programmable control units shall be understood as one or more units which may control one or more algorithms and/or interlocking systems. Typically a control unit may be a programmable logical controller, PLC. However it is obvious that microprocessors can be employed or programmed or programmable electronic circuits in place of PLCs'. The programmable control unit (108,208) is typically arranged in a closed chamber under over pressure, where the chamber is integrated in the device.

[0022] Electrical in and outputs will meet sudden requirements to safety against explosion dependent on the environment for which the inputs/outputs are considered to be used in. Such inputs or outputs are deigned to not produce sparks or current/voltage spikes at connection and disconnection.

The electrical inputs and outputs shall also be interpreted as electrical inputs or outputs which meet other types of requirements to the environment such as pressure, temperature or humidity above particular levels.

[0023] High pressure air inlets or high pressure air outlet shall typically meet the same requirement as those set forth for the electrical in and outputs.

[0024] Output for gas detectors or for other sensors or detectors may require to meet the same requirement as those for electrical in or outputs. According to one embodiment the electrical sensors or detectors will have a fixed connection to an arrangement according to the present invention, Another variant as depicted by figure 1 and figure 2 comprises a number of connections for connection of plugs from detectors or sensors which shall be connected.

[0025] The detector outputs inputs will typically be adapted operation as known to the person skilled in the art from control engineering applications.

Continuous analogue measures for the outputs may comprise 4-2OmA DC which represents 0-100% LEL, I 0-5OmA DC for full manipulated variable, 1 -5V DC, RS232, RS485 or other standardised values known to the person skilled in the art. The power supply to the detectors may typically be within the range 18 -32 V DC. As indicated the output of the detectors may be digital and utilize digital interface of electrical or optical type.

Typically such digital interfaces will be used where a sensor or a detector have an embedded analogue to digital converter. Output for gas detectors will normally comprise power supply to the sensor/detector devices; event though self powered stand alone detector units, being battery driven or powered by rechargeable batteries can be imagined. It is also known detector devices which outputs signals without voltage supply. Said input/output to the detector devices is comprised by all the examples indicated in any combination thereof.

[0026] WiFi equipment that is EX certified is known from prior art and one can imagine distributed sensors or detectors which transmits wireless information to the device according to the present invention.

[0027] Power supply shall be construed as the supply of current which is necessary for operation of a device and an arrangement according to the present invention, The power supply will operate the device as such according to the present invention, including logical circuitry, display means such as LCD displays, alarm devices, output for electrical tools as well as tap to the detectors. The power supply will typically be connected to a transformer which will convert voltage to an appropriate level for said display means, alarms and PLC's.

[0028] By display means it shall be understood that this is a screen being configured to show different operating conditions related to the device according to the present invention.

[0029] In its simplest form the present device will comprise a cabinet with a high pressure air distribution central. The high pressure air distribution central comprises a high pressure air inlet 103, a high pressure air outlet 101 as well as a solenoid 102. The solenoid 102 may as a response to a signal from the logical unit 108 shut off the high pressure air supply to the high pressure air outlet 101. The high pressure air distribution central may additionally be designed with an air filter and a visual inspection flask. As indicated, normally this high pressure air distribution central is certified for use in or adjacent to explosion hazard areas. The cabinet 250 comprises further a power supply 130 with an operating voltage typically equivalent to that of the mains, that is typically 230V AC 50/60Hz and typically with a capacity of I 6A or 110 V AC 50 Hz. It shall be appreciated that the supply also can be 380V AC. The supply current is connected to a transformer and distribution central arranged in the cabinet and which is adapted for explosive environments as the transformer and distribution central may reside in another cabinet 240. The transformer transforms the voltage from the primary side to the secondary side, where the secondary side is adapted for operation of electronics and alarm devices. One may realize a number of transformers according to need or a number of secondary taps to operate a plurality of voltages internally within the cabinet/device 250.

The secondary voltage or the secondary voltages is rectified by one or more rectifiers which reside in the second cabinet 240. A programmable logical control unit-PLC 108,208 is supplied by current from the secondary side of said transformer. The PLC 108, 208 is provided with a number of inputs and outputs with a standard interface adapted for operation and monitoring of detectors/sensors 120. Such a PLC can be programmed to respond to alarm signals generated by the detectors 120 as it transmits signals to the solenoid of the air distribution unit so that high pressure air to the high pressure output 101, 202 is shut off.

Simultaneously or substantially simultaneously the PLC 108, 208 will transmit a signal which trigs the alarm devices 100,200 and 106,206. Still further, the power supply 130 and not at least the power outlet 105,205 will be isolated and/or cut off. The display device 107,207 will preferably display continually updated state for the device and arrangement for secure operation according to the present invention. To render the device movable it is preferably equipped with wheels 109,209 and it is liftable as it may be provided with lifting lugs/fastening ears 230.

Use example of the arrangement according to the present invention [0030] A scenario for operations and start up of t he device according to the present invention may be as follows (fig. 3). One or more persons are invited to carry out mechanical work outdoor on an oil rig. As particularly strict rules apply for doing such works, the person or the persons who is supposed to carry out the work will have to get a permission to work within sudden time spans within clearly indicated restricted areas. The power supply to the device according to the present invention is supplied from a centrally controlled supply which can be switched off from a control room; the same applies to the high pressure air supply. When he or those who shall start working he or they will follow particular procedures which is adapted to the high security environment. The device shall be arranged at a suitable and approved place 300. It must be room around the device to allow inspection of the device and connections to the device. Gas detectors, typically four, will be connected to 301, 320 or alternatively be fixed connected through a cable. These detectors will be arranged remote to the device, typically 20 to 50 meters, and the localisation will be governed among others by the direction of the wind and obviously by the location of sources of explosive gases. Where the detectors 120 is provided with a cable and plug, the plug HC1 will be connected to a connector X-HCI 104, thereafter the plug HC2 320 is connected to connector X-HC2 1 04 etc. Having arranged the detectors at designated locations the supply 130 with typically 230 V -1 6A will be connected to 302, thereafter the input of the air distribution central 103,203 will be connected to 303. Pneumatic tools will then be connected 304 to the air pressure outlet 101,201. Next step in the start up procedure will be to switch on a main switch 305. The device will then read 306 the logical unit 108,208, e.g. the PLC 108, 208. Having read the PLC 108,208 a message 307 will be displayed on the screen of the display device 107,207. The message will typically be SYSTEM OK" 307. The operator or operators of the device according to the present invention will then be able to start 308 the device by pushing an activate button START on the device. The solenoid valve 102,202 will respond by opening an air supply fro the installation, that is, from the air supply inlet 103. The system is now pressurized 310 and pneumatic tools can be activated 311 and/or electrical equipment can be activated 311. During operation the display means 107,207 will continuously display the state, i.e. if for example a detector stops functioning or a detector must be cleaned, the display device 107,207 will indicate this, additionally the system will maintain an optimal security as air supply and electrical supply that is connected to equipment will be shut off, that is a shut down interlocking is performed as described elsewhere in the description. If one or more detectors sense threshold values outside limits of for instance gas, then the arrangement according to the present invention will shut of air and current to connected equipment. For instance if a gas detector HC.-1 120 detects more than LELI 0% gas then the supply of air will be shut off rendering pneumatic tools deactivated. A sound signal from an acoustic alarm device 106 will be activated; light signals from a lamp 100 will also be activated. Further the cLirrent output 105,205 will be disabled so that electrical equipment is also deactivated, In addition to this stepping down with warning the display means 107,207 will display status information.

[0031] It shall be appreciated that by the example for operation shown above the alarm situation will occur before the gas levels and hence the danger of explosion has reached critical levels at the place of work for the user of the arrangement according to the present invention. In occurrences where the user carries a detector on his wrist the earliest reaction would have occurred as the level of gas reached a critical level where the work is carried out. Mechanical work with tools can generate heat, cause sparking and hence constitute a risk if explosive gas or dust reaches critical values.

[0032] Above it is disclosed a mobile device for operation of air pressure tools and electrical equipment in fire-and explosive hazard environments. The interlocking procedures will be controlled by the programmable logical unit or processor 108,208. Hence it shall be appreciated that the device is particularly flexible as said control unit 108,208 is programmable or can be ordered according to customers' requirements if the control unit 108,208 is comprised of programmable or pre-programmed circuits. It is further disclosed an arrangement which comprises the device as well as external detectors. It shall be appreciated that the number of detectors can deviate from the example above where four detectors are indicated. It shall also be appreciated that the detectors can be of different type, both passive and active. The connection between the detectors and the device can be provided in accordance to what that the skilled person in the art finds most

suitable.

Reference numerals to the drawings [0033] Warning lamp, visual alarm device 101 Air pressure outlet 102 Solenoide, solenoide valve 103 Air pressure inlet 104 Output connectors for detectors. The contacts typically designated X-HCn Plug for output of supply voltage to electrical equipment. Typically 23OVAC, med 16A.

106 Acoustic alarm device, such as a siren 107 Display means, typically a LCD panel/screen 108 An electrical control unit such as a PLC 109 Wheel Detectors, generally gas detectors Warning lamp, visual alarm device 201 Air pressure outlet 202 Sole noide, solenoide valve 203 Air pressure inlet 204 Output connectors for detectors. The contacts typically designated X-HCn 205 Plug for output of supply voltage to electrical equipment. Typically 23OVAC, med 16A, 206 Acoustic alarm device, such as a siren 207 Display means, typically a LCD panel/screen 208 An electrical control unit such as a PLC 209 Wheel 230 Fastening ears 240 Second cabinet for transformer and other electrical equipment according to the present invention 250 First cabinet for a device according to the present invention.

Claims

CLAIMS1. A device adapted for operation, control and monitoring of tools and equipment in or adjacent to explosive environment, the device comprises: an input adapted for power supply (130); one or more power outputs (105,205) approved for operation in explosive environments; one or more outputs for gas detectors (104,204), where the outputs meets requirements to equipment for use in expbsive environment; one or more high pressure air inlet devices (103,203) as well as one or more high pressure air outlets (101,201); at least one programmable control unit (108208) configured to shut off high pressure to the one or more high pressure outputs (101,201) and to shut off power supply to the one or more power supply outputs (105,205), and one or more alarm devices (100,106,200,206).
2. Device according to claim 1, c ha r a c t e r i s e d i n that the device further commprises at leas tone display means (107,207) for display of the state of the device.
3. Device according to claim I or 2, c ha r a c t e r i s e d i n that the device further comprises at leas tone solenoide (102,202) for clsosing and opeing of the one or more high pressure air inlets (103,203) and high pressure air outlets (101,201).
4. Device according to one or more of the previous claims, c ha r a c t e r i s e d i n that the programmable control unit (108,208) is arranged in a pressurized closed chamber and the chamber is integrated with the device.
5. Device according to one or more of the previous claims, characterised in thattheoneormorealarmdevices (100,106,200,206) comprises at least one alarm which gives a visual alarm signal (100,200) and at least one alarm which gives an acoustic alarm signal (106,206).
6. Device according to one or more of the previous claims, c ha r a c t a ii s e d i n that the output for the gas detectors (104204) is configured for 10% LEL.
7. Device according to one or more of the previous claims, c ha r a c t e r s e d i n that the at least one programmable logical unit (108,208) is a programmable logical control unit configured to shut off high pressure air outlets (101,201) and current output (105) as well as transmit an alarm signal to the alarm devices (100, 106, 200, 206) at threshold values above 10% LEL..
8. Device according to one or more of the previous claims, characterised in that, the current input (130) is adapted for 230 V 16A alternate current; the one or more current outputs (105,205) comprises one current output (105,205) approved for operation in explosive hazardous environments and approved for 230 V I 6A alternate current; one or more outputs for gas detectors (104,204) comprises four outputs for gas detectors, where the outputs (104,204) meets requirements for equipment for use in explosive hazardous areas; the one or more high pressure air inlet units (103,203) as well as the one or more high pressure outlets (101,201) comprises a high pressure air inlet and one high pressure air outlet (101,201); the at least one programmable control unit (108,208) is configured to shut off high pressure air supply for the one high pressure air outlet (101,201) and to shut off current supply to the current output (105,205), and the one or more alarm devices (100,106,200,206) comprises an acoustic alarm device (106,206) and a visual alarm device (100,200) where both alarm devices is certified for use in explosive hazardous environments..
9. System for operation control and monitoring of tools and equipment in or adjacent to explosive environment; c ha r a c t e r i s e d i n that the system comprises: a device comprising; an input adapted for power supply (130); one or more power outputs (105,205) approved for operation in explosive environments; one or more outputs for gas detectors (104,204), where the outputs meets requirements to equipment for use in explosive environment; one or more high pressure air inlet devices (103,203) as well as one or more high pressure air outlets (101,201); at least one programmable control unit (108,208) configured to shut off high pressure to the one or more high pressure outputs (101,201) and to shut off power supply to the one or more power supply outputs (105,205), and one or more alarm devices (100,106,200,206); one or more gas detectors (120) adapted for connection to the output (104,204) for the gas detectors (120), a cabinet (250) adapted to house the device comprising: the input (1 30) adapted for current supply, the one or more current outputs (105,205), the one or more outputs for the gas detectors (104,204), the one or more high pressure air inlet units (103,203) as well as the one or more high pressure air outlets (101,201), the at least one programmable control unit (108,208) and the one or more alarm devices (100,106200,206) where the cabinet (250) is provided with wheels (109,209) and fastening ears (230).
10. System according to claim 9, c ha r a c t e r i s e d I n that the arrangement is further specified in that the gas detectors (120) comprises four gas detectors (120) adapted for wired connection to the outputs (104,204) for the gas detectors and that the detectors are configured to give an alarm signal at 10% LEL.
11 A method for initialising an interlocking procedure for start up of a device in accordance to the claims 1-8, c ha r a c t e r i s e d i n that at the method at least comprises the steps of: arranging the device (300); connect (301) one or more detectors (320); connect a current supply (302) to the device; connect to an air distribution central (303); connect pneumatic tools to the air distribution central (304); switch on mains switch (305), logical control reads data (306); display means (107,207) displays (307) start up status; push (308) activate button, and solenoide valve (102,202) opens (309) air supply to pneumatic tools.
12. Method according to claim II, c ha r a c t e r i s e d i n that the method further comprises the subsequent steps of: start up of tools (311) and equipment and to enter an operation mode.