Smooth and even control.

Danfoss Power Solutions has partnered with Australian crane manufacturer Franna to improve the performance of its MAC 25 crane. With the PVG 48 proportional valve at the heart of the work and steering subsystems, Danfoss is delivering a reliable, precise, future-proof solution.

Franna, a Terex brand, is a leading manufacturer of pick and carry cranes with a rich heritage of design and engineering excellence. For more than 40 years, Franna has been a leader in the Australian market, and today its products are at work in more than 30 countries across the globe.

Franna’s MAC 25 mobile articulated crane features a maximum lifting capacity of 25 tonnes (27 tons) and a maximum boom length of 18.4 meters (60 feet). The crane offers maximum safety, excellent roadability, intuitive operation, and unmatched versatility. True to the company’s heritage, the crane’s design has been tested, proven, and continuously improved over the years.

In 2021, Franna began looking at other options for the MAC 25 crane’s main control valve. The company required a solution that was precise, reliable, and future proof to accommodate increasingly sophisticated electronic control systems. The Danfoss PVG 48 proportional valve, then in development, emerged as the superior solution.

PVG 48 is a pre-compensated proportional control valve for applications requiring flow rates of up to 180 liters per minute (47.6 gallons per minute). The latest member of the PVG load-sensing valve family, PVG 48 is ideal for machines such as wheel loaders, aerial lifts, and cranes in which precise flow and controllability are essential.

Danfoss launched the PVG 48 valve to the general market in June 2023 with Franna as a key pilot customer. On the MAC 25, the valve turns operator joystick inputs into quick, accurate boom movement.

“The PVG is extremely precise and reliable. It does what you want it to do repeatedly,” said Adam Murchie, project engineer, Franna. “It’s the ideal choice for MAC 25 and likely to end up in other of our cranes, too – not least in future launches where more advanced electronic controls are key. We wanted a future-proof valve. PVG 48 is it.”

Franna MAC25 Crane

The PVG 48 valve integrates easily with electric actuators, sensors, and digital controls, opening a range of possibilities. One of them is to automate certain machine functions so the crane assists – or even takes over from – the operator. Such a function can be advantageous in many situations, particularly when instant reaction is required to ensure safety.

With the change to PVG 48, Franna also switched to Danfoss counterbalance valves. Together with PVG 48, they ensure smooth and safe activation of the crane’s boom.

“Controllability is smooth and even – very refined,” said Quentin Bourke, product support technician, Franna. “The initial tiny bounce on the front tires, which you sometimes see when operators raise or lower the boom, is completely gone. Extension or subtraction of the boom is impressively smooth, too.”

Bourke adds that initial feedback from crane operators using MAC 25 with a PVG 48 and Danfoss counterbalance valves is positive, too.

“Together with Danfoss, we’ve managed to create the exact kind of MAC 25 crane feel that we hoped for,” Bourke said. The these proportional valve is already at work in more than 100 of Franna’s MAC 25 cranes throughout Australia.

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@DanfossPower @Danfoss @TerexCorp @NapierPR #Pauto #Automation

Monitoring of mobile harbour equipment.

Tony Ingham of Sensor Technology Ltd explains how monitoring the work rate of cranes, loaders and unloaders means their performance can be optimised and downtime for maintenance can be scheduled for minimum disruption to operational requirements.

The increasing globalisation of the world economy is pressurising ports, docks and harbours into handling ever-increasing volumes of cargo, so mobile harbour equipment has to work efficiently and reliably at all times. 

Importing and exporting of dry bulk cargos, from minerals to grains, fertilisers to cement, wood chips to agricultural products, is almost exclusively a maritime operation. Thus there is a need to load and unload ships and barges, and in the modern world this has to be done quickly, efficiently and safely.

So as the volume requirements of world trade increase, harbour operators must ensure their loading/unloading equipment is in top condition, always available for use, and able to adapt to new operational, commercial and safety requirements. The best way to maintain such equipment is constant monitoring while it is working. This will allow the work to be totalised so that pre-emptive maintenance scheduling can be optimised, and will also instantly pick up early signs of emerging problems, such as sticking bearings.

The work done is directly related to the totalised load lifted, a parameter that crane and loader operators should also be measuring for both safety and commercial reasons. Constant load monitoring used to be very difficult, but Sensor Technology has developed the perfect solution. Called LoadSense, it was originally used with helicopters carrying underslung loads in cargo nets and has now been adapted for use on ground-based materials handling equipment.

The technology involves a sensor being fitted to each crane or unloader. Once installed this does not interfere with handling operations at all, but constantly sends real time data via a wireless link to a computer, where it can be displayed, stored, totalised and analysed to provide performance information to the operators and billing information for the customers.

LoadSense is an intelligent load sensor that can easily be integrated with a mobile harbour crane. Designed and manufactured by Sensor Technology in Banbury UK, it is fully automatic so causes no disruption to normal operations. Special training is not required; instead comprehensive and easily understood information becomes instantly available to operators and managers alike.

The LoadSense sensor is based on proven strain gauge technology, and is calibrated as standard in the range 1-50 tonnes, with other ranges available on request. It constantly monitors the load and transmits this wirelessly, using the unrestricted 2.4 GHz waveband, to a receiver for onwards transfer to the control computer. This enables accurate load data to be displayed, typically via a colour touchscreen computer, running Windows XP. The screen shows real time measurement of the load, while the computer records and analyses it.

LoadSense has become a favourite amongst harbour crane operators as an important enabling technology to improve safety, asset availability, productivity and profitability. For instance, you may need to know how much material you have transported, or you could be handling two or more materials simultaneously which need to be accounted for individually. A common scenario is where multiple customers’ cargos are being handled at the same time; here LoadSense gives operators the information they need in order to invoice each appropriately.

LoadSense also enhances safety and prevents dockside handling equipment from failing catastrophically. There are typically two reasons for such failures:

• Overloading the crane with too much weight. Because LoadSense is constantly producing a digital signal, it is easy to set up the control computer with an overload value that will trigger an alarm if it is breached. It is equally simple, and practically better, to set the computer so that it will cut out lifting operations if the overload limit is breached, thus ensuring excessive loads are not raised off the ground.
• Aging cranes and unloaders can suffer fatigue failure. LoadSense can be used to keep count of the number of operational cycles performed, and signal when the equipment’s design life is being approached. An inspection can then be conducted to determine the likelihood of imminent failure and remedial works that can be undertaken.

In conclusion we can say that to be profitable harbour operators need to work their dockside handling equipment long and hard and that the best way to ensure reliability and safety is by constantly monitoring the load and interpretation of the ensuing data. LoadSense from Sensor Technology makes this requirement completely automatic and foolproof.

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@sensortech #Pauto

Crane performs electronic acrobatics!

A crane control refurbishment project at Clydeport’s Hunterston terminal (GB) relies on Parker SSD AC890 series system drives to deliver pinpoint control in the unloading of coal from vessels. The massive crane can lift up to 36 tonnes of coal in a single grab, allowing loads to be deposited reliably and accurately into the dockside hopper, even in inclement Scottish weather and winds of 40mph or more.

Clydeport operates Scotland’s main west coast ports, with Hunterston located on the Clyde Estuary in North Ayrshire providing a world class bulk coal facility. Hunterston has the natural advantage of having one of the deepest sea entrance channels in northern Europe; does not have to be dredged on an annual basis, and is flexible enough to cope with even the largest vessels afloat – up to 350,000 tonnes.

Formerly known as the Hunterston Ore Terminal, the facility was built on reclaimed land in the late 1970s by the former British Steel Corporation to land iron ore and coal, the raw materials for the Ravenscraig Steel Plant (Motherwell). Ravenscraig closed in 1992 and the terminal was bought by the Glasgow-based Clydeport port management company to handle coal.

The long travel dockside crane at Hunterston is one of the largest in Britain, but at over 30 years old its control system was beginning to show its age. Relying on mechanical brakes and thruster brakes, operation could be a nerve wracking business in the typically challenging weather conditions. In addition, mechanical wear and damage were ongoing problems, with the squaring of wheels and worn out tracks. Modern ports demand absolute efficiency, and demurrage – the compensation paid to the owner of a vessel which has been delayed in port beyond the agreed time – can be considerable.

To inject a new lease of life into the crane, Clydeport decided on a major refurbishment of the control system, and put the project out to tender. Among the keys to success would be the ability to integrate seamlessly with the existing Ward Leonard field control system, and to provide regenerative braking with an active front end (AFE) tied to the dock power supply. The former would maintain Clydeport’s own engineering personnel’s familiarity with the system, giving them increased confidence, while the latter would be key to increased control and energy efficiency.

The tender was won by Stockport based system integrator T&M Machine Tools, with owner Tom Yates developing a control system built around Parker SSD AC890 series drives with AFE technology for regenerative braking. Yates comments: “AC drives normally dissipate braking energy by using dynamic braking resistors. However, crane applications can operate much more efficiently with an active front end. Here the drives are on a common DC bus where the overall system shares the line’s energy, with the active front end providing a clean, efficient method to regenerate the drive’s braking energy directly back into the line as required.”
Each of the crane’s legs has four 37kW motors. The control solution developed by Yates divides these into eight paired sets, each under the control of an AC890 drive.

The control panel itself was built for Yates by the systems department at Parker SSD’s Littlehampton facility, which also provided full engineering support for the wider upgrade project. Yates worked closely with Parker SSD to develop the AFE regenerative braking system, with the full regenerative operation giving the crane drivers pinpoint joystick control of the traverse movement of this massive crane. “The AFE regenerative braking allows a lot of energy to be dissipated very quickly, giving very accurate control even in heavy winds,” says Yates.

The crane can lift up to 36 tonnes of coal in a single grab, raising it 100ft or more out of the vessel and into a dockside hopper, which feeds the coal onto a conveyor system away from the dockside. In a business where speed is critical if demurrage is to be avoided, the Hunterston terminal boats unload at speeds of over 2000 tonnes per hour, ensuring a quick turnaround for carriers. “The operators find the refurbished crane much easier to drive, which gives them a lot more confidence, and so helps to boost unloading efficiency. They can drive the crane faster, confident that they have pinpoint accuracy of traverse movement. Even in high winds, the crane can perform electronic acrobatics,” says Yates. “Also, mechanical wear is significantly reduced, so maintenance requirements are simplified, and further potential for demurrage is eliminated.”

Testament to the success of the upgrade is the fact that T&M Machine Tools has been awarded the contract for a second crane. “This is another job where I shall definitely be working with Parker SSD,” says Yates. “The products are extremely capable, and the engineering support from Littlehampton is excellent.”