Preemptive Contamination Control

The centralized hydraulic system you needed was finally approved, installed, plumbed, and tested. The new system should provide a big boost to your plant’s productivity. It has state-of-the-art load-sensing pumps which will save energy and provide more than enough power to run the production line. Proportional valves with on-board electronics are mounted on the cylinders to control speed, acceleration, and positioning, and radial-piston motors with resolver feedback will provide powerful and precise control of conveyors.

The design of the centralized hydraulic system also includes a pressure filter to protect proportional valves, return line filters to protect any contamination coming back from components, an offline filtration system for continuous filtration and cooling of the oil, and last, a suction strainer with a 3-psi bypass to keep out large contaminants. The boss is excited because of the promised energy savings and production uptime resulting in more profit.

This is where most plant personnel wash their hands, relax, and set the cruise control, because they got this centralized hydraulic system running which will solve all their problems for the next 20 years. That sounds amazing…but the reality is this is only the beginning.

Another step that’s just as critical, if not more so, is to develop a maintenance strategy/program. This step is the backbone of energy savings and reliability. You cannot afford any downtime; otherwise, you’ll have to suffer the wrath of the plant manager for agreeing to spend the capital on this new hydraulic system. The question is, what does a maintenance program look like?

Mapping Out a Plan

Many plant personnel believe a maintenance strategy is to fix something when it breaks down and change the oil at specified intervals. This plan is reactive and preventive, which are lagging indicators of failures and provide us with no information about how the hydraulic system is running. If we move into the predictive and proactive realm, understanding how failures occur becomes relevant, making the 20-year goal now attainable.

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Hydrostatic Trencher can Dig Automatically

Vermeer’s T-755 hydrostatic tracked trencher combines toughness with technology. The powerful machine is designed for digging in rock, cross-country trenching or working drainage and utility projects on roadways. The T-755 cuts trenches as deep as 10 ft and 14- to 36-in. wide at chain speeds of 397 to 724 ft/min. These operations and more are monitored and controlled by Vermeer’s Smarttec electronic control system for versatility and ease of operation. The system also records key functions for proactive maintenance and operator performance analysis. Its software provides real-time operator prompts based on operating conditions.

Vermeer’s T-755 hydrostatic trencher uses a low-speed, high-torque motor fed by two pumps to drive its trenching chain. Although it’s shown here cutting into dirt, it’s just as capable digging into rock using rotary, carbide-tipped cutters.

Traction and Trenching Circuits

The T-755’s dual-path hydrostatic drive, powered by a 275-hp @ 2,200-rpm diesel engine, uses a matching pump, hydraulic motor, and planetary transmission in a separate circuit for each track and is capable of full counter-rotation. A 4-pad pump drive box transmits torque and rotational speed to a pair of pumps that supply the traction and another pair powers the low-speed, high-torque trenching motor. Maximum transport speed for the 37.5-ton machine is 170 ft/min, with digging speeds from 0 to 91 fpm. Practical cutting speed ranges from 400 to 670 fpm, depending on the application and operating conditions. The machine’s service brakes also are hydrostatic, parking and emergency brakes are spring-applied, hydraulically-released.
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Cat bolsters mini hydraulic excavator lineup

Caterpillar introduced a number of micro and mini excavators during this year’s GIE+EXPO.

The manufacturer says that new models come standard with several new customer-centered features.

First up are the four micro excavators that pack considerable power in the 1-to-2-ton class. There is the 301.5 that has a canopy, standard tail swing and is in the 1.5-ton class; the 301.7 CR that has a compact radius and canopy and in the 1.7-ton class;  the 301.8 is in the 1.8-ton class with standard tail swing and options for either a canopy or a cab; and the 302 CR is in the 2.0-ton class and has a compact radius. Operators have the option of a canopy or a cab.

The 301.5 is ideal for the entry-level landscaper. The 301.8 is suited for heavy lifting and the 302 CR offers site stability for heavy duty jobs.

One of the most notable features of these new excavators is the Stick Steer system. This allows operators to swap from a conventional lever/foot-pedal steering controls to left-hand joystick control of the bucket. This improves operator control with less effort.

“Great operators are few and far between, so machines need to be simple,” says Greg Worley, senior product engineer.

The controls are designed to be intuitive and each model comes with a Next Generation LCD monitor for machine information. Comfort has also been a focus for these models with adjustable wrist rests and a suspension seat available. The models where a cab is optional are pressurized and sealed to reduce dust and air conditioning is available with the climate control system.

All models are powered by the Cat C1.1 engine, a three-cylinder diesel rated at 19.2 net horsepower and 21.6 gross horsepower that meets Tier 4 Final standards. Dig depths are 7 feet 8 inches or 7 feet 9 inches depending on the model.

To boost versatility, the standard auxiliary hydraulic system provides one way, two way and continuous flow. Each model comes standard with an expandable undercarriage. All models retract from 51.2 to 39 inches, except the 302 CR, which retracts from 55.1 to 42.9 inches.

Read more: Cat bolsters mini hydraulic excavator lineup

Safety Valve System

The Hydraulic Block & Bleed valve system features a manifold base mounted design available in body sizes D03, D05, and D07; port sizes SAE-8, SAE-12; and 1¼ Code 61 Flange. A relief valve is also featured on inlet, and position sensors enable external monitoring. Tamper-resistant design prevents unauthorized personnel from altering the valve. The system blocks hydraulic supply pressure and bleeds downstream pressure back to tank for added safety. This is a redundant 3/2 normally closed function valve system, spool-type design, direct solenoid or solenoid pilot-operated. External monitoring allows safe redundant operation and position sensors enable external monitoring by an electrical safety control system.

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Wacker Neuson Introduces New 10-foot Hydraulic Ride-on Trowel

Wacker Neuson’s new 10-foot hydraulic ride-on trowel is being introduced to reflect the demanding needs of the professional concrete contractor. The CRT60X (CRT60-74LX) features a heavy-duty hydraulic system that includes a high capacity hydraulic pump and motors, as well as other ancillary components. These updates have been made to address the ever increasing demands of the flatwork industry. In addition, creature comforts have been added to include a new display and lighting.

The new CRT60X features:

  • A new display that allows the operator to quickly and easily see information such as machine hours, fuel level, engine rpm, fluid temperatures and pressures as well as alerts; all the information the operator needs in an easy-to-read display. This is the same display and diagnostic system that has been incorporated into Wacker Neuson’s skid steers and compact track loader lines.
    LED lights for improved lighting at night and low light concrete pours. The LED lights are brighter and will last longer than traditional lamps.
  • Patented built-in hydraulic wheel kit. This is a real time saver by allowing operators to easily raise the machine on the front and back wheels to change blades or install pans without the need of a forklift or cranes. The built-in system also allows for easier movement around the job site or shop.
  • Operator comfort features include an electronic cruise control, adjustable seat, plenty of legroom, ergonomically positioned arm rests, simple joy stick controls and fully hydraulic blade pitch providing tireless operation.
  • Powered by a 74-hp Kohler, non DPF Tier 4 Final engine. The engine provides power needed for a professional finish by providing a stable, consistent engine and pan speed.
  • The CRT60-74LX can easily maintain rpm under a high load finishing condition.
    A gyro assisted steering feature compensates for any unwanted machine rotation and allows the operator to stay on a steady course with less fatigue.
  • The unit continues to feature a patented power steering system. Wacker Neuson was able to combine fully hydraulic drive performance with a dual mode power steering system that makes operation more comfortable and the trowel more responsive to the operator’s command.
  • The dual mode system allows the operator to select the response of the joysticks to meet their preference and best suit the concrete condition.
  • The patented engine power regulation system continues to be an important feature of Wacker Neuson’s ten foot professional rider. Similar to an automatic transmission in a car, this innovative system will constantly monitor engine speed and adjusts the hydraulic load, allowing the unit to seamlessly run at optimal engine and blade speed for maximum power input to the concrete.
  • Wacker Neuson’s 60-inch, CRT60X is the largest model of Wacker Neuson’s extensive concrete ride-on trowel line. The unit offers a high blade speed, hydraulic blade pitch, 2-speed engine throttle and large 12-gallon fuel tank that offers four hours of uninterrupted run time. With six blades per rotor and a width of 123-inches, Wacker Neuson’s CRT 60X is the ideal machine for professional concrete contractors looking for high performance on large jobs. This is the ideal machine for high volume professional concrete contractors looking for an easy to operate, high performance trowel for large jobs.

Read more: Wacker Neuson Introduces New 10-foot Hydraulic Ride-on Trowel

Volvo CE Unveils All-Electric Compact Excavator Prototype

We previously reported on the recent introductions of a refuse truck and mini excavator that both use electric drives to power each vehicle and its hydraulic system. Eliminating the internal-combustion engine from these machines make them quieter and with zero emissions.

Volvo Construction Equipment (Volvo CE) has taken this concept to the next level with its latest concept machine, EX2. The EX2 is a100% electric compact excavator prototype incorporates an electric drive for propulsion, but also for work functions. So, yes, it uses electromechanical actuators and no hydraulics.

The EX2 was presented at the Volvo Group Innovation Summit in London, UK, alongside innovations from across the Volvo Group, including an autonomous refuse truck from Volvo Trucks and an electric bus from Volvo Buses. The innovation summit centered on infrastructure and transport in cities of the future and focused on how the industry can have a positive impact on society through increased transport efficiency, reduced environmental impact and improved traffic safety.

Electrifying Innovation

The Volvo Group defines electromobility as “commercial vehicles and machines that can utilize an electrical motor to propel or to perform the main purpose of the machine.” To make the EX2 prototype fully electric, the internal-combustion engine has been replaced with two lithium ion batteries, totaling 38. kW-hr, which store enough electric energy to operate the machine for eight hours in an intense application, such as digging compact ground.
The hydraulic system has also been replaced with electric drives that incorporate electromechanical linear actuators. Removing the hydraulic system and the gas or diesel engine reduces cooling demand and significantly reduces noise. At this time, the EX2 is purely a research project, and no plans currently exist for production.

Read more: Volvo CE Unveils All-Electric Compact Excavator Prototype

Best Practices Move Beyond the Basics

An overwhelming amount of technical documentation presents valuable advice on such topics as the importance of keeping hydraulic fluid clean and why you should change the filters on a regular basis. These basics are second-nature to most hydraulics engineer and technicians. Although basic practices cannot be overlooked, executing best practices can move hydraulic contamination control to the next level.

Fluid cleanliness. Ensure that any fluid is filtered before it goes into the hydraulic reservoir. Fresh hydraulic fluid often is not clean enough to put into a system. So if you can’t verify that the fluid has been filtered to your system’s specifications, run it through a filter before transferring it into the reservoir.

Monitor fluid condition regularly. This means use laboratory-grade analysis on a schedule determined by the operating conditions, not an arbitrary timetable. Always flush a system to manufacturer’s specifications or in line with ISO standards every time components are replaced or repairs performed.

1. A high-pressure filter with visual and electrical indicator is mounted directly downstream of a pump in the hydraulic system’s HPU. The hydraulic system actuates a weir, or gate, in a dam that lets municipal workers control water level in a small lake.

Filter maintenance. Monitor the filters and change them before they go into bypass mode. Again, this requires a schedule based on the operating conditions, not an arbitrary timetable. Make sure replacement filter elements comply with the original manufacturer’s specifications.

Read more: Best Practices Move Beyond the Basics

Unique Hydraulic Auto Lock Cylinders Raise Portable Military Radar

The Thales Groundmaster 200 is a mobile military radar system by Thales Raytheon Systems, the joint venture between Thales and Raytheon in France. The GM200 is an autonomous tactical radar solution for Air Surveillance and Control. It is small enough to be embedded in a standard 20-ft ISO shipping container, transported by air, fitted entirely on a tactical vehicle, and operational in a short time.

Hydraulic equipment from French supplier Quiri is used to lift and maintain the mast and radar antenna. There are three operator positions for deploying the radar when mounted on a truck. Each Ground Master 200 radar system has one Quiri double-acting cylinder to push it up from its stored position to the low position and two synchronized telescopic lifting cylinders that push it up to the high position.

Thales Raytheon Systems’ GM200 is a tactical Air Defense Radar that provides an accurate detection against targets from very low to high altitudes and from short to medium ranges, whatever the environment.

The double-acting cylinder for low position rotation has a 400-mm stroke and 120 kN compression force. The telescopic double-acting cylinders for lifting and deployment provide a total stroke of 3,500 mm and 30 kN compression force. A 5.5-kW embedded hydraulic power unit has a double-outlet pump that supplies the telescopic cylinders with equal flow for extension and retraction operating pressures from 40 to 160 bar.

The cylinders themselves have electroless-nickel plated piston coating and accumulators that can handle the extreme environments specified by the military, with working operating temperatures from −40° to 30°C.

Read more: Unique Hydraulic Auto Lock Cylinders Raise Portable Military Radar

Pumping Up: Is Hydraulic Lifter Pump-Up A Real Problem Today?

There is an age-old decision that high performance engine builders must make: hydraulic lifters, or solid lifters? Typically, (or more accurately, traditionally) the school of thought has been that hydraulic lifters were a better choice for street engines that accumulated a lot of miles at varying RPM, and solids were a better call for race engines that spent more time at high-RPM and were rebuilt regularly.

These opinions were created way back in the flat-tappet era, and followed the respective designs into the modern roller generation. Since hydraulic lifters did not require adjustment once they were set, they were a lower-maintenance item that street enthusiasts would appreciate. Setting hot lash was an art form reserved for the more hardcore race crowd. Certainly, the stability of a solid lifter offered consistency and strength to survive extended periods of high-RPM use, and by setting the lash at the minimum, every thousandth of an inch of precious lift and every degree of duration would be delivered to every valve.

At idle, the reduction in oil pressure would allow a bit more civilized idle in the hydraulic designs, while the solids would demand perfect adjustment to deliver a signature “crisp” lopey idle sound, and the requisite mechanical performance advantage to match.

Well race fans, it’s deep into the twenty-teen years now, and most of those ancient myths are busted. Modern technology and advanced engineering are blurring the line between hydraulics and solids. While both designs have seen durability increase over the years (mostly due to improved materials, tighter tolerances, and wider roller bearing surfaces), the real advances have been on the hydraulic side of the fence.

Modern engineering has led to more precise plunger, spring, and retainer systems. These have resulted in more consistent fluid control, both in and out of the lifters. Combined with the rest of the aforementioned advances, and with the benefit of decades of research on every part of the lifter design, the modern hydraulic roller lifter gives up little, if anything, to its solid counterpart. The benefits of the hydraulic design, especially that lack of a need to set lash or adjust anything once it’s set properly and locked down, brings plenty of benefit to enthusiasts whose valve covers aren’t easy to access.

The current trend toward turbocharging brings with it a commitment to relatively exotic plumbing. The deep engine setback of modern performance cars makes pulling valve covers a real challenge. Not having to do so between races (or, in extreme cases, between rounds) is a real gift. Certainly, improved poly lock designs have really helped minimize the need to set valve lash on a regular basis. Compared to the early parts racers had back ten or twenty years ago, things are much improved.

Read more: Pumping Up: Is Hydraulic Lifter Pump-Up A Real Problem Today?

Robust Seal Systems Key to 10-Year Life of Tensioner Cylinders

The tensioner cylinders used to support subsea drilling and production risers where they connect to the rig are the size of an 18-wheeler. They are in motion 24/7 and must accommodate 50-ft strokes during storms. With a cost of up to $100,000 to ferry one onshore for refitting and return it to the rig (not including lost production costs), it’s little wonder rig operators insist that every cylinder they install lasts at least 10 years.

That’s a tall order for the seals contained within the system—not only because of the wear requirements, but also the water glycol fluids used in offshore systems. The fluids are more environmentally friendly than mineral oil-based fluids, but they exhibit poor lubricity (especially low film strength and low viscosity), which is detrimental to many seal materials, including rubber.

Redundancy and Wear-Resistant Materials
Successfully creating a sealing system that meets the requirements of an offshore tensioner cylinder involves extensive experience with these types of systems; flexible (yet strong) and wear-resistant seal and wear ring materials that are compatible with water glycol fluids; and inclusion of a secondary seal and wiper.

Key considerations for the primary seal include wear life, friction, and fluid compatibility. A highly wear-resistant seal material is essential to ensure the seal system is leak-free for as many years as possible. However, the seal must also be able to move constantly within the water-based fluid system with as little friction as possible and withstand the aggressive chemicals used to inhibit corrosion.

Seals composed of rubber-based materials tend not to perform effectively in these types of systems. They are prone to compression set and chemical attack, and their friction coefficient is higher than that of polytetrafluoroethylene (PTFE)- and polyethylene (PE)-based seals. The primary seals in tensioner systems are typically composed of PTFE or PE variants and are the first line of defense against leaks.

Read more: Robust Seal Systems Key to 10-Year Life of Tensioner Cylinders

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