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.

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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.

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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.

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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

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Hydraulic Upgrades Enhance Aerial Lift Performance

Hydraulics technology plays an important role in the aerial devices the utility industry uses to reach and service electric lines. Cylinders on these truck-mounted lifts operate the booms that raise buckets or platforms carrying workers and equipment to heights that may reach up to 65 ft., with side-reach capabilities that can exceed 50 ft. on some models.

When Terex Utilities designed its Optima series of Hi-Ranger devices, the company addressed performance, productivity, and maintenance—three top concerns of its electric utility customers, according to Joe Caywood, director of marketing at Terex, Watertown, S.D. Starting with its proven Hi-Ranger design, the company incorporated several product improvements that provide greater vehicle payload capacity, better boom speeds, enhanced side reach and ground access, and features that improve maintenance access and reliability.

Terex Optima Series aerial lift uses hydraulics to raise and position utility workers for their work on distribution lines, as well as for handling materials and powering tools.

Machine Benefits from Hydraulic Upgrades
Although some of the upgrades required structural changes—such as using high-strength steel to reduce aerial weight and increase vehicle payload capacity—others focused on modifications to the equipment’s hydraulic system. For example, a higher-capacity pump provides greater flow, which translates into higher boom speed and allows operating multiple functions simultaneously with no reduction in speed. This also called for upgrading some valves to accommodate the higher flow rates, as well as improving the routing of hydraulic lines. Ultimately, these improvements boost the machine’s productivity.

The Optima aerial lifts are available with either an open- or closed-center load-sensing hydraulic system, with pilot-operated valves used on the closed-center version. The open-center system uses a vane pump, while the closed-center system has a pressure-compensated piston pump. A single-stick control is used in the work bucket for both systems, whereas the ground controls use individual levers.

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Aircraft Hydraulic System Market: Business Opportunities, Current Trends, Market Forecast & Global Industry Analysis by 2023

The Aircraft Hydraulic System Market Report provides thorough backdrop investigation of Aircraft Hydraulic System business, with an evaluation of the previous years. The Aircraft Hydraulic System Market Reports provides data on Aircraft Hydraulic System patterns and improvements, and target business sectors and materials, limits and advancements. The report broadly provides the market size, share, trends, growth and forecasts to 2025.

“The Aircraft Hydraulic System market was valued at Million US$ in 2017 and is projected to reach Million US$ by 2025, at a CAGR of during the forecast period. In this study, 2017 has been considered as the base year and 2018 to 2025 as the forecast period to estimate the market size for Aircraft Hydraulic System.

The Aircraft Hydraulic System Market report begins from Synopsis of Aircraft Hydraulic System Industry Chain structures and Industry Environment, then analyses market size and forecasts of Aircraft Hydraulic System by Key Players, Product Types, and Applications, additionally, this report includes Market Competition situation of Aircraft Hydraulic System among the Major Manufacturers along with company profiles.

Major Key Players of Aircraft Hydraulic System Market Report: United Technologies Corporation, Parker Hannifin Corporation, Safran S.A., Eaton Corporation PLC, Liebherr-International AG, Woodward, Inc., Triumph Group, Inc., Moog Inc., Arkwin Industries Inc., Beaver Aerospace & Defense, .

Aircraft Hydraulic System Market Segment by Product Types considering Production, Revenue (Value), Price Trends:

Open-Center
Closed-Center
Aircraft Hydraulic System Market Segment by Applications considering Consumption Growth Rate and Market Share:

Civil Aircraft
Military Aircraft
Helicopter
The study objectives of Aircraft Hydraulic System Market Report are:

To study and forecast the market size of Aircraft Hydraulic System in global market.
To analyse the global Key players, SWOT analysis, value and global market share for top players.
To define, describe and forecast the market by type, end use and region.
To analyse and compare the market status and forecast between China and major regions, namely, United States, Europe, China, Japan, Southeast Asia, India and Rest of World.
To analyse the global key regions market potential and advantage, opportunity and challenge, restraints and risks.
To analyse competitive developments such as expansions, agreements, new product launches, and acquisitions in the market.

Read more: Aircraft Hydraulic System Market: Business Opportunities, Current Trends, Market Forecast & Global Industry Analysis by 2023

 

Hydraulic Seals Designed for Heavy Duty

Machines operating in harsh environments often encounter wide swings in pressure and temperature shock loads, and sometimes side loads that present major challenges to seals in hydraulic cylinders. This report outlines the challenges of preventing seal leaks and keeping contaminants out of the hydraulic system.

Selecting the right seals for a specific heavy-duty application can be a daunting task without the expertise of a manufacturer with deep technical and engineering roots matched by field experience. Based on decades of technical knowledge and partnering with equipment manufacturers to design, test, and implement sealing solutions, the following are some of the most common piston, rod and wiper seals used in heavy-duty applications.

Challenges for Piston Seals

Piston seals are designed to prevent pressurized hydraulic fluid from leaking past a cylinder’s piston from one end of the cylinder to the other. This internal leakage wastes energy and can cause the piston to drift from a stationary position. It can also reduce extension and retraction speed and make positioning difficult.
Piston seals are selected by the amount of time, direction, pressure, and work to be done by the hydraulic cylinder. The challenge is for the seal material to maintain tight contact with the cylinder bore to prevent leakage while also resisting wear from the friction produced from the sliding motion with the bore. Common materials used for manufacturing single- and double-acting piston seals include polyurethane, rubber-fabric composite, PTFE, or polyester elastomers.

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Compact Excavators Adopt Big Machine Features

For the past decade full-sized excavators have adopted new technologies and features that make them more productive and fuel efficient. Now many of these features and technologies are trickling into the compact excavator market.

“More and more often compact excavators are being tasked to do the job of their larger counterparts, so they are equipped with greater hydraulic flow for improved hydraulic attachment/tool versatility, larger better-equipped cabins and fleet management/telematics to help manage machine location, usage, downtime, etc.,” says Lee Padgett, product manager, Takeuchi-US.

Comfort features from full-size machines are also trickling down into compact excavators. “It was not that long ago that none of the compact excavators had air conditioning,” recalls Tom Connor, product manager, Bobcat. “Now it is a fairly high take rate as far as a factory option.” Cabs have also continued to grow. “When the zero tailswing craze took off 15 years ago, one of the quick ways to help get to zero tailswing was to shrink the cabin space.” In the last five years, creative engineering has gained back space for the operator. “We were able to get about an inch and a half more in width of the cab, which doesn’t sound like a lot, but in a cab that size, it is actually quite noticeable. It allows us to put a wider seat in the machine.”

Bobcat E35Bucket64a320716u5FcBobcat offers several seat choices tailored to customer requirements. “For the R Series, the standard seat is a vinyl suspension seat on an open canopy machine,” says Connor. “But you can option that up to a cab with heat and air that comes with a cloth seat, which is a nice upgrade, especially in the hot weather.” You can even go above that and order a heated cloth seat in the cab-enclosed options.

According to John Comrie, product manager, compact equipment, Volvo Construction Equipment, larger cabs and air conditioning allow operators to focus more on the work with less fatigue, potentially extending the working season. “Many of Volvo’s compact excavators, like the ECR88D short swing model, offer the same features and spacious cabs found on our full-size machines,” he notes. Compact excavators increasingly have not only more cab space and foot room, but also storage. “Operators are often spending an entire day inside these machines. They want to focus on their work with minimal fatigue.”

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Equipment Showcase: Pumps

Pumps and pumping systems have multiple applications in power plants and can be located in several locations throughout a facility. These pumps are generally centrifugal and positive displacement pumps. Centrifugal pumps use an impeller to move fluid through the application process, with the velocity of the rotating impeller imparting energy on the liquid, causing a rise in pressure proportional to the fluid’s velocity. Positive displacement pumps move liquid with pressure generated from resistance to movement of the liquid downstream of the pump. The liquid being handled usually determines which pump technology to use. Some of the leading manufacturers and service companies for pumps serving the power generation industry are featured here.

Sulzer Launches New CPE End-Suction, Single-Stage Centrifugal Pump

Sulzer’s new CPE ANSI process pumps are specifically designed to exceed the strictest energy regulations for all industries as well as the requirements of ASME B73.1. With revolutionary hydraulics and high efficiency, they offer low lifecycle costs. The new CPE pumps meet the process requirements in a variety of industrial applications, and are suitable for use with clean or slightly contaminated liquids, viscous liquids of up to 3,000 centistokes, and fibrous slurries with a consistency up to 6%. Sulzer’s engineering of the new range of CPE pumps can bring cost savings, along with improved reliability and reduced risk for unplanned shutdowns thanks to optimization of the shaft sealing. Heavy-duty rigid bearing units ensure a long bearing life and further protection against unexpected shutdowns. The new pump design brings higher efficiency that translates into lower energy consumption.

Read more: Equipment Showcase: Pumps

 

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