Hydraulic direct drive powers mine conveyor

Conveyors are critical to mine production, and certainly to a mine that refines around 350 million metric tons of ore and pellets per year.

One such mine was the first in Brazil to equip a belt conveyor with a Hägglunds hydraulic direct drive system – a milestone in Brazil with significance for the rest of Latin America.

The Hägglunds system replaced an electromechanical drive with independent electric motors, each run at a constant speed and coupled with a speed reducer.

With its infinitely variable speed and resistance to shock loads, the hydraulic direct drive system offered clear production advantages.

But for the mining company, the strongest argument was safety.

The company had carried out a feasibility study, which highlighted potential improvements in safety and beyond.

With a hydraulic direct drive on the conveyor, all rotating parts would be enclosed rather than exposed.

There would be no sensitive couplings, and the motors themselves would have their own internal relief system. In total, this would mean a safer conveyor with greater reliability.

For all of these reasons, a hydraulic direct drive was installed at the mine.

Comprising two hydraulic Hägglunds CB400-320 motors, as well as a hydraulic pump unit and a Rexroth control system, it was installed in only three days.

“The motors were a good choice for the torque demand,” says Sales Engineer, Roberto Akira Koga at Bosch Rexroth, “and the tight integration between our teams helped us get the solution in place quickly.

Since installing the new drive solution, safety has indeed improved. Moreover, the reliability of the belt conveyor is far greater.

According to the mining company’s records, eliminating the low-speed coupling between the transmission and conveyor drive drum has done away with a good deal of maintenance.

“Maintenance is definitely lower with the direct drive solution, and the smoother, softer belt starts reduce wear and tear,” says Mr Akira. “The system now also absorbs any torque peaks, and it can be operated at a wide range of speeds to meet different process requirements.”

In fact, the hydraulic direct drive still has more to offer. Measurements show that the conveyor now carries around 2700 tons per hour, and that its capacity is slightly more than it was with the original drive system.

But thanks to the flow rate and power of the newly installed drive, it is possible to substantially increase the speed or torque without affecting the service life of the drive.

“The diagnostic tests that have been carried out show that the drive system is in excellent condition, and that the mining company can increase its production volume significantly if the needed,” says Kjell Byström, Engineer at Bosch Rexroth. “The company is very satisfied, which has been our experience virtually every time a hydraulic direct drive has been installed on a conveyor. It’s a pleasure to see.”

Read more: Hydraulic direct drive powers mine conveyor 

Redefining Through Disruption

When trying to describe the continuously evolving world, the acronym “VUCA” is particularly apt. In defining a set of challenges with which oil and gas professionals have become all too familiar, it stands for volatile, uncertain, complex and ambiguous.

The industry has been operating in “crisis mode” with the collapse of the oil price and the prolonged industry downturn, forcing the entire sector to shift its focus and acclimatize to the “new normal.”

In the recent past the focus was on increasing production and expanding into new geographies and basins. Companies now operate under the imperative of maximizing productivity and efficiency, lowering opex and enhancing flexibility to allow field viability at lower oil prices.

What, then, is the best way to navigate the industry’s constrained environment? Companies need to look at the tools and resources they have at their disposal to respond to today’s challenging demands and build a sustainable and prosperous long-term future for oil and gas.

With middle classes in the emerging world expanding and driving the global demand for energy, the industry has an important role to play. Today’s volatile market, however, calls for a new set of priorities.

Read more: Redefining Through Disruption 

Troubleshooting Challenge: No Pressure on a Simple System

A coil steel processing plant recently had a machine that ran 24/7 when the plant was operational; it lost all hydraulic pressure. Plant personnel had emailed me a copy of the original hydraulic schematic (shown) they were given when the unit was installed, hoping I could help them solve the problem over the phone.

They kept telling me a directional valve was mounted on top of the relief valve. One of the mechanics thought it was added during commissioning and debugging to fix a problem with the electric motor not having enough power to get the system up and running. The solution at the time was to add a single solenoid directional control valve to the top of the relief. They also felt the system ran hot from day one.

The circuit symbol indicated a directly operated relief valve, but it probably was a pilot-operated unit, which would allow changing the head to a solenoid-operated relief/unloading valve. This would let the electric motor build speed with no load. Energizing the added-on solenoid would provide a safety relief setting.

Some time after the system was operational, a more powerful electric motor was added. The unloading feature was not used so the directional valve was left energized, rendering the valve as a safety relief any time the system was running.

I told technicians to check the control orifice in the main stage of the relief valve and to make sure the directional valve on top was working properly. To do this, my instructions were to check the pilot poppet and spring. They assured me all was okay, but they still had no pressure and planned to replace the pump, which had a 10-week delivery promise.

I visited the job site and had trouble believing it was the pump. Everyone had an opinion about the pump, cylinder, directional control valve, and even the accumulator. What do you think was the problem?

Read more: Troubleshooting Challenge: No Pressure on a Simple System 

Interviews with Earthmoving Manufacturers: Technology-Enabled Solutions

As part of RER’s continuing interviews with earthmoving manufacturers, we interviewed Mitch Tobias, Caterpillar Inc. customer enterprise digital manager; Steve Brown, Caterpillar, global rental marketing & operations manager; and Jason Hurdis, Caterpillar, senior market professional about how advanced digital technology has impacted earthmoving equipment.

RER: What are the latest technological developments with your equipment?

Tobias: We recently launched our 988K Wheel Loader and D8T Dozer remote control systems as a part of our Command technologies.

What trends do you see and do you expect to see in earthmoving equipment in the near future?

Tobias: We would expect the use of technology in many areas to continue to increase and become more common practice. Some of the most recent advances that would be built upon are Grade Control, Payload, and Intelligent Compaction. Customers will continue to migrate to the use of these tools to assist in improving productivity, lowering material costs, increasing safety of their workforce, and reducing time of projects. A great reference video is: https://www.youtube.com/watch?v=6nF2YIf9r-k&feature=youtu.be

There was a lot of interesting technology at the Conexpo show, such as use of drone technology in earthmoving equipment, virtual reality training and more sophisticated use of telematics. What were some of the new technological advancements you have made?

Tobias: Also at the show, we had a D8T Dozer located in Peoria, IL being controlled remotely from the operator station at the exhibit in Las Vegas. The new Cat Command remote control system for the D8T offers a choice of two operator interfaces— a portable operator console designed for line-of-sight use and an ergonomically designed operator station that can be located remotely when the dozer is equipped with the Command Vision system. Wireless connectivity enables the operator to work from a safe location, whether nearby or far away. Additionally, we demonstrated a remote control skid steer loader at Conexpo as well.

It appears that hybrid machines are now more popular than in the past? Do you find more of a demand for them in the rental market?

Brown: From an OEM perspective, we see rental demand often mirrors retail. Hybrid machines are becoming more popular in rental fleets as customers are seeing value in the technology.

Are you finding increased demand for any particular kinds of machines from the rental market?

Brown: We are seeing an even distribution in demand across our product segments. Increased investment in infrastructure and commercial construction are pulling products across our portfolio into dealer rental fleets.

Read more: Interviews with Earthmoving Manufacturers: Technology-Enabled Solutions 

Pipeline services portfolio

Valuable new services from a single supplier have recently been brought to market to enable users in the oil pipeline sector to increase their flexibility and benefit from cost advantages.

Before these new services came the Parflange system developed by Parker, which continuously flares and then flanges the tube during its cold-forming procedure.

Since its introduction, it has proved highly effective with regard to mechanical strength and long working life.

Furthermore, this method is 9 to 12 times faster than comparable welding. On top of this, cleaning the tube before and after the manufacturing process is not necessary.

The Parflange process is always environmentally friendly since no dangerous gases occur, like they do with welding and brazing, and heating up before the manufacturing process is also not necessary.

It was from this technology that the Parflange F37 system was developed, enabling tubing systems of various sizes to be connected to each other. It uses the orbital tube forming technology for tubes from 16 to 273mm outside diameter and is intended for wall thicknesses up to 9mm and pressure ratings up to 420 bar.

For connections in which no pre-formed tube can be assembled, the F37 retaining ring system is available. Here the flange is held on the tube by a retaining ring that, together with a high-tech seal carrier, ensures leak-free connections.

The Parflange F37 system offers distinct advantages compared with classical welding; the preparation time per tube-end is shorter and the not inconsiderable costs for cleaning the tube and checking after welding are quite simply not required.

Also, the tube connections show constantly high quality and accuracy. As a result, installation times are shorter and the project time overall is also shorter as well.

Parker has developed its Complete Piping Solutions (CPS) system around this technology. It has been put together from several modules such as consultation, piping layout, pre-assembly, delivery and installation, from which the customer can put together his tailor-made concept for the manufacture of piping systems or, when required, can make use of all the above-named services.

Now, the concept is being extended with two additional modules. Parker Onsite Containers were developed, amongst others, for service in the offshore and shipbuilding sectors. They contain all the assembly machines that are required for preparing the assembly of tubes from 6 to 60mm diameter. If required, much bigger tubes with outside diameters up to 273mm can also be prepared.

Read more: Pipeline services portfolio 

Going with the Flow: A Quick Overview of Power Units

To understand the basics of hydraulics, it is best to start off learning about the standard power unit. Once a person knows how this integral system operates, it will be easier to learn about more complex hydraulic systems. Further study can help engineers troubleshoot and validate system designs.

A power unit converts mechanical power into fluid power, which can be used to drive an actuator. An actuator is generally a cylinder, motor, or rotary actuator that is controlled by a directional valve. A power unit must meet the power demands of the system by producing enough force or torque to move the load.

Six basic components, illustrated in the schematic below, make up a power unit. They all work together to transmit power to the actuator and keep fluid clean.
The first component in a power unit is the prime mover. Electric motors are commonly used as prime movers in industrial hydraulics, while gas and diesel engines are more commonly used in mobile hydraulics.

The prime mover supplies mechanical power to the pump via shaft connection. This transfer of energy allows the pump to overcome hydrostatic pressure in the closed circuit, and creates a vacuum relative to the atmospheric pressure, which pushes fluid from the reservoir into the pump inlet, and generates flow throughout the system. There are three basic types of pumps. They are gear, piston, and vane pumps.

Read more: Going with the Flow: A Quick Overview of Power Units 

Fluid Power Trends

When I was first approached to write this article, my mind was a whirl of state space equations and complicated closed loop hydraulic applications – I mean, whose wouldn’t be? After much thought (and some sound advice), I decided to describe a growing industry trend that starts with a human resource factor.

In earlier days, the hiring trend in the hydraulics industry was to pull from a talent pool that comprised people with primarily mechanical backgrounds. The overall shift away from this kind of hiring – to instead draw people from a broad, diverse and multidisciplinary background – has led to many advancements in the industry. These advances can be seen in both the product development being done by manufactures, as well as the overall system design development by integrators.

My own path through the hydraulic industry is an example of someone entering the hydraulics industry from a nontraditional background. I got my start in the Electrical Engineering Technology – Control System program at Humber College in Ontario. After starting with Motion Industries (Canada) Inc. as an electrical specialist, I worked closely with both Motion’s shop services and their tech team to provide programming and system design support on capital project-based work. Lots of automated hydraulic, lubrication and pneumatic systems, with the odd purist VFD/servo application of course. I ended up going back to school for a degree in electrical engineering and now manage Motion’s Calgary Service Center, as well as their team of system designers.

Industry Insights

As a result of this journey, I have realized several things. First and foremost, I love this industry. It has been my distinct pleasure to work with some of the best and brightest out there, and I am eternally grateful for that opportunity.

Second, there’s a lot of overlap in electrical/mechanical world; I mean, we all follow the same laws of physics, right? Some of the best programmers I’ve met came from a mechanical or even chemical background and had a strong aptitude for the work. I think the same is true from the automation to hydraulic world. The crossover in theory is very easy to adapt and is, in fact, quite intuitive.

Third, the hydraulics industry is ever-evolving. As things like integrated amplifiers, modular controls, better PID and tuning algorithms and the overall electrification of the hydraulic world continues to advance, so do the possibilities for system design. Those who adapt and embrace these changes (OEM machine builders, systems integrators, product designers) are going to be the ones driving this industry into the future. They will also be the benefactors of being on the leading edge of technological advances.

Trend watch

As far as industry trends go in the hydraulic world, this electrification/automation of things is by far the most prevalent and one that is still developing. Every day, it seems a new product is being offered and always with an integrated electrical control, amplifier or other embedded device. Things like combining electrical servo motors with a fixed displacement pump would have been an odd sight a decade ago. As would including a particle counter as a permanent installation to improve a customer’s preventative maintenance.

Advances in building inexpensive, reliable, integrated circuits with massive processing abilities is finally spilling out of the “Tech Sector” into the “Industrial Sector” at an exponential rate. This has allowed manufacturers to provide relatively lower-cost, advanced product offerings.

Read more: Fluid Power Trends

Deere announces top-of-the-line six-cylinder tractors

An engine boost of 37.2kW (50hp) through Deere’s Intelligent Power Management (IPM) provides the flagship 6250R with up to 223kW (300hp) when required.

Both models weigh 9300kg in their standard form but both tractors can be ballasted up to 15 tonnes.

Both new tractors are powered by a 6.8 litre PowerTech PSS engine with dual turbochargers which use Diesel Particulate Filters and Selective Catalytic Reduction to adhere to Final Tier 4 emission standards.

The SCR system is a post-combustion treatment of the engine exhaust gases and requires the use of diesel exhaust fluid, or AdBlue, at the rate of about two to three percent of diesel fuel use.

PUNCHY

The engines punch out maximum torque at 1600 engine revs of 1074nM and 1167nM respectively for the 6230R and 6250R. Fuel tank capacity is 470 litres while the Adblue tank can hold 29 litres. The wheelbase on both tractors is 2900mm.

John Deere has upgraded the AutoPowr transmission for the two new models which allows for 100% mechanical power available at 3.5km/h for heavy draft operations, 11km/h for light draft work, 22.5km/h for heavy transport and 47.2km/h for light transport duties.

Once running at maximum road speed, engine revs automatically drop and 50 km/h is maintained at 1630rpm and 40km/h at a miserly 1300rpm.

HYDRAULICS

Equipped with a pressure and flow compensated hydraulic system, the 6R tractors have a maximum flow of 160 litres a minute at 1500rpm. Up to six hydraulic couplings or SCVs with individual pressure-relief levers are available and lift capacities are 10.4 tonnes on the rear hitch and five tonnes at the front. The front hitch can be optioned with two hydraulic couplings.

The 6230R and 6250R tractors also feature hydro-pneumatic cab suspension (called HCS Plus) which helps isolate noise and vibration from the cab interior.

Self-levelling TLS Plus Triple-Link suspension is also new on the front axle. The system automatically adjusts sensitivity and suspension rate, and synchronises with hitch sensors to compensate for power hop under heavy draft conditions.

Key service points on the new 6Rs include a 750-hour engine oil filter, fuel filter and engine oil change over interval.

Read more: Deere announces top-of-the-line six-cylinder tractors 

New Optidrive™ developed by Avant to improve engine performance

Avant has developed a new, innovative solution for improving the performance of the drive circuit in Avant loaders.

The drive system in Avant loaders consists of a variable displacement hydraulic pump, four hydraulic drive motors and some valves which are connected together with hydraulic hoses and fittings. This system where the drive power is conveyed from engine (electric motor on Avant e-series) to the wheels using hydraulic oil is often referred to as drive circuit. Instead of mechanical axles Avant uses a design where there are four separate hydraulic drive motors, one on each wheel of the loader.

Avant was the first manufacturer to design and utilize such a system in a compact loader. This system has proven to be very effective, offering lots of pushing power and yet enabling a very compact design to the loader while maintaining an extremely low center of gravity, which is an important part of the great stability of Avant loaders.

Through research and development Avant has now improved this system with an innovative way of rethinking. When hydraulic oil flows at high flow rate in the drive circuit – in hydraulic hoses, fittings, motors and valves – the resistance in these components heats up the hydraulic oil. The more there are hoses and fittings, the quicker the oil heats up, which means that all that unnecessary heat generated in the system uses a part of the engine output in vain. This also results in higher fuel consumption and less engine power is available for the actual job.

In the new system the amount of hydraulic hoses and fittings has been radically reduced and optimized, where the name Optidrive™ derives from as well. The new Optidrive™ is a standard feature first in Avant 700 series, later also in the 500 and 600 series.

Read more: New Optidrive™ developed by Avant to improve engine performance

The City’s Aging Dams Are Getting a Costly Check-Up

The city of San Diego worries some of its dams “may be nearing the end of their useful service life” and is spending up to $5 million to see how they’re doing.

Last year, city officials hired an engineering firm to do detailed checkups on each of the city’s nine dams. Carlsbad-based GEI Consultants has been working quietly ever since on a study that could take up to five years.

Most city dams are 80 years or older.

Brent Eidson, a spokesman for the city water department, said the study may ultimately find that no significant work is needed on the dams.

Officials already have a few concerns, though. In fall 2014, for instance, the city limited the amount of water it can store in the lake formed by the El Capitan Dam near Alpine, which is the city’s second-largest reservoir.

That’s because officials spotted water seeping out from underneath the dam. Some seepage is normal, but it could also be a sign of problems.

Read more: The City’s Aging Dams Are Getting a Costly Check-Up 

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