Explore all the options
19 Jan 2009
Simple and straightforward they may seem, but weighing and measuring systems are now being used for an increasing number of much more complicated tasks. Load cell weighing units, for example, are not the type of equipment normally considered for oil production operations on an offshore platform in the North Sea. However, this is where weigh modules and portable weighing terminals are helping improve oil production efficiency.
Tank weigh modules from Mettler Toledo, for instance, have been specially modified to suit the hostile North Sea environment, but the ATEX-certified stainless steel load cells are normally hermetically sealed to IP68 for harsh industrial applications. An anti-uplift bolt is incorporated to restrain the tank and prevent it from lifting too far - a feature that is especially useful for protecting against wind pressure in exposed, exterior locations, like offshore platforms. The portable stainless steel weighing terminal (IND429) is protected to IP69 in accordance with DIN 40050 for water ingress and is Ex certified for Zone 2 hazardous areas.
So why would you want to weigh a tank and its contents on a North Sea platform?
The weighing system is an integral part of the RBG Sand Management System, which recovers and separates sand from oil production flows. RBG is an integrated provider of oil, gas and petrochemical services, operating from an Aberdeen base. Its patented hydrocyclone-configured desander recycles water, while discharging recovered oil to the drains system.
Removed sand, contaminated with oil, is collected in the weigh tank to assess batch composition prior to dosing with cleaning agents. Accurate management and monitoring of the batch size enables the waste to be dosed with the correct quantity of chemicals for cleaning, leading to optimised performance and reduced chemical usage.
"Oil recovered from the waste is reintroduced into the process" commented the RBG implementation manager, James Calderwood: "This improves yield and also removes contaminants [the sand] from the waste, making it suitable for overboard discharge. Removing the recovered oil has significant cost savings for the client, as the oily waste would otherwise need to be shipped from the offshore platform to a specialist disposal contractor onshore".
The RBG system currently cleans the oil sand and monitors that it is less than 1% oil content. It can then be discharged overboard as it is less than the legislative recommended limit level for such discharges.
Another unusual offshore application for displacement sensors is in monitoring the structural movement of various platform components; the measurements are then used in long-term finite element analyses. The measurements are taken on the structure, pipelines, derricks, moorings and other critical high-stress members of offshore oil platforms.
Custom designs of high pressure and seawater submersion resistant LVDT position sensors have been developed by Macro Sensors for these duties. They are also used for incorporation into sub-sea measurement systems, where the design life is required to exceed 20 years at water pressures of up to 7,500psi. Underwater, they are used for measuring the positions of the valves on sub-sea oil well control towers located at the wellhead, as well as for controlling or measuring the position of robotic arms and actuators.
To minimise the number of pressure-sealed connections and I/Os, a 4-20mA two-wire, loop-powered sensor is used. This signal is then converted to an RS485 signal by a digital converter contained in a high-pressure sealed bottle located nearby, before transmission to the water surface.
Weighbridges can offer almost as demanding and harsh environmental conditions for load cell operation as offshore installations. Driver-operated weighbridges are playing an increasingly important role in today's quarrying industry, offering a number of operational advantages, especially in terms of vehicle throughput, extended working hours and improved data accuracy.
Weightron Bilanciai has described how two well established technologies, automatic number plate recognition systems and electronic signature pads, are now bringing further efficiency benefits to weighbridge systems. ANPR systems can be used to operate traffic lights and control security barriers - and number plate details can also be programmed directly into the designated weight terminal to include haulier details, product descriptions and even vehicle tare weights. This can remove the need for double weighing in some applications, thereby speeding up collection or delivery procedures.
Electronic signature pads will act as a permanent record for each weighing, and the signatures can be printed on paper receipts, as drivers may be required to sign so that they can gain entry to and/or exit from any particular weighbridge.
In many applications weighbridges are located at some distance from the main offices and hard wiring traditionally has been necessary to establish an appropriate recording communications link. Now solar power recharges local battery units, and robust wireless technology is making it far easier to maintain the communications link between the remote weighing terminal and an office-based PC system.
Wireless systems are also proving useful in avoiding the time and cost for installing cables when retrofitting weighing systems, such as on large grain silo installations.
Mantracourt Electronics is a specialist in the design and production of a range of electronics for monitoring and displaying the outputs of load cells and strain gauges, and this includes various innovative radio telemetry systems. One example involved the use of wireless strain gauges contained in the shackles of standard skip chains on road vehicles. Here a hand-held display provides a sum of the two sensor measurements to indicate the skip weight. This can be zeroed before each collection and, when the customer load is added, a wireless-linked thermal printer in the vehicle cab can provide a ticket showing date, time and collected load weight information.
Mantracourt's fluid management system is used to monitor the contents of oil storage tanks. It will also control and monitor the consumption of each grade of oil via a radio telemetry link to the dispensing flowmeter in the delivery lines, for example in a garage or maintenance shop.
Each delivery transaction is transmitted to a local PC, where it is recorded and allocated to the individual operator using their PIN security code, which allows efficient accounting. The load cell monitoring of the tanks can trigger automatic re-ordering when needed.
Weighing systems are well established in food packaging and novel systems have been developed to fine-tune pack target weights based on real-time, factory-floor data. The Marco LineMaster portion control scales use a simple 16-segment, coloured traffic light bar graph to give a clear indication of when the pack weight comes within weight tolerance. Operators soon 'tune-in' to such visual systems and simply pack to the 'green light' without having to think about the actual weights.
Marco has developed software to ensure that packs meet the packer's code for 'e' weighing and minimises expensive product giveaway.
Accurate weighing of portions of fresh or sticky products, such as chicken breasts or fish fillets, can now be effectively addressed by use of screw-feeding multi-head weighers. Rose Poultry, located in Denmark, processes a total of 300,000 chickens every day using this type of weigher supplied by Cabinplant.
"We installed the first screw-feeding multi-head weigher from Cabinplant in the summer of 2005," said Thomas Loeth, co-owner of Rose Poultry: "With this solution we can achieve an accuracy which far exceeds that of traditional grade systems. It easily reduces giveaway to below 0.5%, and compared to a line grading solution we have now reduced the need for labour by up to 80%."
Klaus Wraa, production manager at Aker Seafoods Denmark, applied Cabinplant equipment to his fresh fish fillets: "We now have two complete lines and using multi-head weighing for our fresh fish fillets results in a considerable reduction of giveaway," he said.
Cabinplant, of Denmark, developed the first screw-feeding, multi-head weighing systems and has various patents pending on equipment now spread from Russia to Chile. A demonstration of its latest system for packing ready meals to a fixed weight was held at its factory in November last year.
Three screw-feeding multi-head weighers on one line used in-feed and distribution tools combined with other equipment, such as piston fillers, tray dispensers and conveyors. Designed to pack ready meals to a fixed weight at a rate of 120 trays per minute, the line has one significant advantage in that the product dispensed by the last two weighers can be used to adjust total portion weight to the desired target.
Two new designs of screw-feeding, multi-head weighers have been introduced by Ishida. The first features three-litre, stepper motor-driven, anti-stick metal hoppers and is particularly suitable for larger target weights and larger piece-size applications, including on-the-bone products. It has a top speed of 80 units a minute. The second version incorporates 1.5 litre pneumatic-driven plastic scraper hoppers with a maximum speed of 60 units/minute
Modern rotating filling machines are designed to handle bottles that vary in capacity and weight, and are capable of operating at speeds up to 400 per minute while the machine is rotating. Filling any vessel at such a velocity requires constant weight monitoring to control the whole filling process.
Stork Food & Dairy Systems produces these types of machines and they frequently incorporate advanced weighing systems from Penko. These are MID-approved control systems that regularly undergo initial verification of machine performance and checking by the authorities.
Three phases of bottle filling are used for liquids that are at risk of creating foam. Usually this requires the fill probe to sit beneath the surface for the main delivery to provide a slow fill that creates a 'bottom' level. This is followed by what is termed a 'coarse fill', with the operation completed by a slow final fill and cut-off. The weight is measured at a sample rate of around 1,000 measurements a second.
The major benefit of this method is that the high level of weighing accuracy, combined with the high repeat measuring speed, reduces filling inaccuracy so that 75% of the bottles emerge filled to within one standard deviation from the mean. This results in less over-filling and increased profit for the plant.
Tank weigh modules from Mettler Toledo, for instance, have been specially modified to suit the hostile North Sea environment, but the ATEX-certified stainless steel load cells are normally hermetically sealed to IP68 for harsh industrial applications. An anti-uplift bolt is incorporated to restrain the tank and prevent it from lifting too far - a feature that is especially useful for protecting against wind pressure in exposed, exterior locations, like offshore platforms. The portable stainless steel weighing terminal (IND429) is protected to IP69 in accordance with DIN 40050 for water ingress and is Ex certified for Zone 2 hazardous areas.
So why would you want to weigh a tank and its contents on a North Sea platform?
The weighing system is an integral part of the RBG Sand Management System, which recovers and separates sand from oil production flows. RBG is an integrated provider of oil, gas and petrochemical services, operating from an Aberdeen base. Its patented hydrocyclone-configured desander recycles water, while discharging recovered oil to the drains system.
Removed sand, contaminated with oil, is collected in the weigh tank to assess batch composition prior to dosing with cleaning agents. Accurate management and monitoring of the batch size enables the waste to be dosed with the correct quantity of chemicals for cleaning, leading to optimised performance and reduced chemical usage.
"Oil recovered from the waste is reintroduced into the process" commented the RBG implementation manager, James Calderwood: "This improves yield and also removes contaminants [the sand] from the waste, making it suitable for overboard discharge. Removing the recovered oil has significant cost savings for the client, as the oily waste would otherwise need to be shipped from the offshore platform to a specialist disposal contractor onshore".
The RBG system currently cleans the oil sand and monitors that it is less than 1% oil content. It can then be discharged overboard as it is less than the legislative recommended limit level for such discharges.
Another unusual offshore application for displacement sensors is in monitoring the structural movement of various platform components; the measurements are then used in long-term finite element analyses. The measurements are taken on the structure, pipelines, derricks, moorings and other critical high-stress members of offshore oil platforms.
Custom designs of high pressure and seawater submersion resistant LVDT position sensors have been developed by Macro Sensors for these duties. They are also used for incorporation into sub-sea measurement systems, where the design life is required to exceed 20 years at water pressures of up to 7,500psi. Underwater, they are used for measuring the positions of the valves on sub-sea oil well control towers located at the wellhead, as well as for controlling or measuring the position of robotic arms and actuators.
To minimise the number of pressure-sealed connections and I/Os, a 4-20mA two-wire, loop-powered sensor is used. This signal is then converted to an RS485 signal by a digital converter contained in a high-pressure sealed bottle located nearby, before transmission to the water surface.
Weighbridges can offer almost as demanding and harsh environmental conditions for load cell operation as offshore installations. Driver-operated weighbridges are playing an increasingly important role in today's quarrying industry, offering a number of operational advantages, especially in terms of vehicle throughput, extended working hours and improved data accuracy.
Weightron Bilanciai has described how two well established technologies, automatic number plate recognition systems and electronic signature pads, are now bringing further efficiency benefits to weighbridge systems. ANPR systems can be used to operate traffic lights and control security barriers - and number plate details can also be programmed directly into the designated weight terminal to include haulier details, product descriptions and even vehicle tare weights. This can remove the need for double weighing in some applications, thereby speeding up collection or delivery procedures.
Electronic signature pads will act as a permanent record for each weighing, and the signatures can be printed on paper receipts, as drivers may be required to sign so that they can gain entry to and/or exit from any particular weighbridge.
In many applications weighbridges are located at some distance from the main offices and hard wiring traditionally has been necessary to establish an appropriate recording communications link. Now solar power recharges local battery units, and robust wireless technology is making it far easier to maintain the communications link between the remote weighing terminal and an office-based PC system.
Wireless systems are also proving useful in avoiding the time and cost for installing cables when retrofitting weighing systems, such as on large grain silo installations.
Mantracourt Electronics is a specialist in the design and production of a range of electronics for monitoring and displaying the outputs of load cells and strain gauges, and this includes various innovative radio telemetry systems. One example involved the use of wireless strain gauges contained in the shackles of standard skip chains on road vehicles. Here a hand-held display provides a sum of the two sensor measurements to indicate the skip weight. This can be zeroed before each collection and, when the customer load is added, a wireless-linked thermal printer in the vehicle cab can provide a ticket showing date, time and collected load weight information.
Mantracourt's fluid management system is used to monitor the contents of oil storage tanks. It will also control and monitor the consumption of each grade of oil via a radio telemetry link to the dispensing flowmeter in the delivery lines, for example in a garage or maintenance shop.
Each delivery transaction is transmitted to a local PC, where it is recorded and allocated to the individual operator using their PIN security code, which allows efficient accounting. The load cell monitoring of the tanks can trigger automatic re-ordering when needed.
Weighing systems are well established in food packaging and novel systems have been developed to fine-tune pack target weights based on real-time, factory-floor data. The Marco LineMaster portion control scales use a simple 16-segment, coloured traffic light bar graph to give a clear indication of when the pack weight comes within weight tolerance. Operators soon 'tune-in' to such visual systems and simply pack to the 'green light' without having to think about the actual weights.
Marco has developed software to ensure that packs meet the packer's code for 'e' weighing and minimises expensive product giveaway.
Accurate weighing of portions of fresh or sticky products, such as chicken breasts or fish fillets, can now be effectively addressed by use of screw-feeding multi-head weighers. Rose Poultry, located in Denmark, processes a total of 300,000 chickens every day using this type of weigher supplied by Cabinplant.
"We installed the first screw-feeding multi-head weigher from Cabinplant in the summer of 2005," said Thomas Loeth, co-owner of Rose Poultry: "With this solution we can achieve an accuracy which far exceeds that of traditional grade systems. It easily reduces giveaway to below 0.5%, and compared to a line grading solution we have now reduced the need for labour by up to 80%."
Klaus Wraa, production manager at Aker Seafoods Denmark, applied Cabinplant equipment to his fresh fish fillets: "We now have two complete lines and using multi-head weighing for our fresh fish fillets results in a considerable reduction of giveaway," he said.
Cabinplant, of Denmark, developed the first screw-feeding, multi-head weighing systems and has various patents pending on equipment now spread from Russia to Chile. A demonstration of its latest system for packing ready meals to a fixed weight was held at its factory in November last year.
Three screw-feeding multi-head weighers on one line used in-feed and distribution tools combined with other equipment, such as piston fillers, tray dispensers and conveyors. Designed to pack ready meals to a fixed weight at a rate of 120 trays per minute, the line has one significant advantage in that the product dispensed by the last two weighers can be used to adjust total portion weight to the desired target.
Two new designs of screw-feeding, multi-head weighers have been introduced by Ishida. The first features three-litre, stepper motor-driven, anti-stick metal hoppers and is particularly suitable for larger target weights and larger piece-size applications, including on-the-bone products. It has a top speed of 80 units a minute. The second version incorporates 1.5 litre pneumatic-driven plastic scraper hoppers with a maximum speed of 60 units/minute
Modern rotating filling machines are designed to handle bottles that vary in capacity and weight, and are capable of operating at speeds up to 400 per minute while the machine is rotating. Filling any vessel at such a velocity requires constant weight monitoring to control the whole filling process.
Stork Food & Dairy Systems produces these types of machines and they frequently incorporate advanced weighing systems from Penko. These are MID-approved control systems that regularly undergo initial verification of machine performance and checking by the authorities.
Three phases of bottle filling are used for liquids that are at risk of creating foam. Usually this requires the fill probe to sit beneath the surface for the main delivery to provide a slow fill that creates a 'bottom' level. This is followed by what is termed a 'coarse fill', with the operation completed by a slow final fill and cut-off. The weight is measured at a sample rate of around 1,000 measurements a second.
The major benefit of this method is that the high level of weighing accuracy, combined with the high repeat measuring speed, reduces filling inaccuracy so that 75% of the bottles emerge filled to within one standard deviation from the mean. This results in less over-filling and increased profit for the plant.
