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.

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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.

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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.

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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.

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Troubleshooting Challenge: Pump Shaft Seals Blowing Out

A specially designed trenching excavator was built to dig a drainage line and lay plastic drainage tile at the same time. The drainage tile was coiled up on the back of the trencher, conveyed over the top of the machine, and placed into the freshly dug trench by a bucket. A trailing plow would push the dirt back into the trench, covering up the tile. The special design allowed a single machine to perform all of these operations at once. As a result, farmers could begin planting as much as four weeks earlier than when using up to three conventional pieces of equipment.

Workers would erect a single pole with a laser that rotated 360 deg., and a laser receiver on the trenching excavator positioned the depth of the trench. The laser output was tilted at an angle so that the drainage tile would be laid with a slight pitch to direct early spring moisture away from the fields.

The hydraulic system was controlled with proportional valves to maintain the proper depth of the bucket and plow. The system’s pump was located below the reservoir, with the case drain routed up to the top and into the reservoir. A standard filler breather incorporated a 25-µm filter element. The pump intake line, which came out from the bottom of the reservoir, had a ball valve shutoff.

The excavator was stored in a heated barn in the winter, and it seemed to work well even in zero-degree weather. Every so often, though, the shaft seal would blow out after the machine was started in cold weather. Workers took the machine back into the barn to remove the pump, only to find it in great condition. Before re-installing the repaired pump, they blew compressed air into the case drain line, which seemed free of any restrictions. They were using a low-viscosity hydraulic oil formulated for use at low temperatures. Workers did notice that the problem only occurred in the cold weather when the machine had been left outside overnight.

Read more: Troubleshooting Challenge: Pump Shaft Seals Blowing Out

Caterpillar introduces new Next Generation 36t excavators

Caterpillar has introduced its new Next Generation 36t size class excavators — the 336 and 336 GC — which are designed to increase operating efficiency, lower fuel and maintenance costs, and improve operator comfort compared to previous models.

According to Cat, the new excavators offer unique combinations of features designed to match contractors’ productivity and cost targets. The new 336 features standard integrated Cat Connect Technology and the most power and lift capacity of the two models for maximum productivity at the lowest cost. The new 336 GC, meanwhile. combines the right balance of productivity features with reduced fuel consumption and maintenance costs for high reliability and low-cost-per-hour performance.

The new 336 has the industry’s highest level of standard factory-equipped technology to boost productivity, says the manufacturer. Integrated Cat Connect Technology increases operating efficiency by up to 45% over traditional grading operations. The standard Cat Grade with 2D system provides guidance for depth, slope, and horizontal distance to grade through the standard touchscreen monitor, making operators more accurate. The system is readily upgradable to Cat Grade with Advanced 2D or Cat Grade with 3D.

Among its several features and smart work aides for operators, the standard Grade Assist automates boom, stick, and bucket movements so operators can stay on grade with single-lever digging. Cat Payload delivers precise load targets and increased loading efficiency with on-the-go weighing and real-time payload estimates without swinging to prevent truck over/underloading. The E-fence feature prevents the excavator from moving outside operator-defined set points—particularly useful when working beneath structures or near traffic.

By design, Cat Next Generation excavators produce more work per unit of fuel than the models they are replacing, says Caterpillar — up to 15% more fuel efficiency for the 336. New Smart mode operation automatically matches engine and hydraulic power to digging conditions, optimising both fuel consumption and performance. Engine speed is automatically lowered when there is no hydraulic demand to further reduce fuel usage. The cooling system features a new fan that runs on demand to keep the excavator working at the correct operating temperature for maximum efficiency.

With a new electrohydraulic system built for responsiveness and efficiency, the Cat 336 and 336 GC feature a new main control valve that eliminates the need for pilot lines, reduces pressure losses, and lowers fuel consumption. Fewer hydraulic lines on the excavators result in less oil required, lowering long-term operating costs.

Read more: Caterpillar introduces new Next Generation 36t excavators

Expansion Plugs Provide Leak-Tight Sealing of Fluid Channels

Expansion plugs provide a permanent, leak-tight sealing of fluid passages in hydraulic manifolds, castings, and other components without having to use O-rings, threads, or sealants. Several methods exist for installing the plug and expanding its circumference to establish as tight seal against the inside diameter of the drilled hole.

Ball style—Originally developed as an alternative to threaded plugs, ball style expansion plugs simplified the machining of the end of the drilled hole. The plug’s design uses a simple +0.12/−0.00 mm) counterbore hole to ensure a permanent, leak-proof seal, at pressures to 6,250 psi (350 bar) at a 3:1 safety factor.

Installation for low-volume applications is accomplished using a set tool and hammer or an arbor press, tapping or pressing the ball down into the sleeve until reaching its final desired position. In higher-volume applications, operators air hammers or automate equipment is used to drive the ball into the sleeve, thus speeding up the installation.

Rivet style—developed about 30 years ago, rivet-style plugs again simplified machining of the end of the drilled hole, requiring only a straight bore (+.12 mm/−0). The design often requires a smaller plug being than with the ball style. Rivet-style plugs introduced a hydro-pneumatic installation tool to secure the proper installation of the expander, virtually eliminating any potential installation error by relying on the tool to break the plug vs. an operator pressing the ball to the proper depth.

Operators insert the plug into the hydro-pneumatic tool, press the plug against the hole to be sealed, and depress the tool’s trigger. With the tool maintaining flush contact with the surface of work piece, the internal components of the tool grab a mandrel while holding the body of the plug just below the surface of the workpiece. The tool draws the pin into the body until the necked down area of the plug reaches its desired break point. When this occurs, the pin fully engages the body, causing radial expansion sealing the hole at 7,250 psi (500 bar) at a 3:1 safety factor. A quick, simple, and cost-effective permanent seal, the rivet style plug was an improvement to expansion plugs for many applications.

A Newer Option
These two options come in a variety of material choices, sizes, pressure ratings, and installation tools. The EIS pull plug was introduced in 2013 and automatically threads the plug onto the installation tool’s mandrel until ready to insert into the hole for sealing. Unlike the ball-style plus, the EIS Pull Plug does not require a counterbore, nor does it rely on the reaching a break force, as with the rivet-style plug

Read more: Expansion Plugs Provide Leak-Tight Sealing of Fluid Channels