Power Team has launched a newly redesigned website with enhanced features that let users more easily search products and product specifications. The company manufactures high-force

SPX Hydraulic Technologies is a leading manufacturer of high performance, fluid-power equipment, bolting equipment, and railway products. Visit the new site at www.powerteam.com for a complete product listing, application stories, technical manuals, product specifications, a product selection guide, material safety data sheets, and more.

Power Team
powerteam.com

Windpower Engineering & Development

The Optima vT is said to configure to a wide range of testing specs.

Alternative energy technology developers looking for leak detection equipment that can be custom configured to their particular test-application requirements without added costs, can obtain a competitively priced and first-of-a-kind leak and flow tester from uson — the Optima vT Leak and Flow Tester. The device includes one or two test channels with four sensors each, totally customizable pneumatics, multiple built-in automated calculators, myriad data handling and storage options and other features that combine to make the Optima best-match test technology for the most leak and flow-test applications.

R&D for the multi-function single or dual channel leak and flow tester began in 2009 and incorporates uson’s knowledgebase of the wide ranging requirements for leak detection and flow testing.

If a situation calls for production speed on the order of a million parts a year including highly accurate and multiple tests, the company says its Optima can be configured to do so. If a variety of tests must be done in sequence, such as a pressure decay followed by a series of flow tests in different ranges, that is doable too.

The unit is said to configure to widely varied testing specifications. The company has helped design test equipment when it first developed dry-air leak testers for NASA.

A few features of the Optima vT Leak and Flow Tester include:

• Capabilities for vacuum decay tests, pressure decay leak testing, differential pressure decay leak tests, mass flow leak detection (including back pressure and differential), upstream and downstream cracking pressure, pressure rise tests, burst tests, laminar flow tests, force decay testing, and occlusion testing
• State-of-the-art microcontrollers comparable to those used in the most demanding consumer electronics applications
• 2 channels with up to 4 sensors/channel, for up to 8 sensor inputs
• Simultaneous testing on all sensor inputs
• Built-in automated calculators to speed testing and data handling
• Fully customizable pneumatic controls
• Large easy-to-read full color touch screen display with intuitive user interface

Uson
www.uson.com

Windpower Engineering & Development

Rotary union -Deublin

Valve selection provides a good example of the complexity that comes in just selecting one component. Selecting a proportional hydraulic valve for pitch control is an important task. From a functional viewpoint, valves in turbine hydraulics are not required to do anything unusual. They simply control the flow of fluid to cylinders in response to sensor signals in a fairly straightforward closed-loop servo control circuit.

However, the valves are subject to temperature extremes, high and variable rotational and vibration loads, and long periods between maintenance. Servicing such valves requires the attention of specialized personnel.

In response to the wind industry’s need for more precise control, proportional valves are being equipped with an improved control interface featuring CANbus communication using the CANopen protocol. These electronic controls are packaged to industry IP67 environmental standards to meet the needs of the next generation of wind turbines. Fittings and hoses should be considered critical components. They are key components in gearbox lubrication, typically an active system with constantly circulating fluids. Hoses with class-zero leakage do not weep in extreme temperature variations or on cool down, so selecting them eliminates a potential source of fluid loss. Such hoses also promote a safer working environment inside the nacelle by keeping its floor drier and delivering extended service lives.

Premium hoses made with Teflon PTFE are resistant to bulging under pressure, making them a good choice for critical braking circuits. They are also chemically inert which is important in gearbox lubrication circuits. Color coding these devices helps prevent assembly errors on shop floors, and potentially catastrophic failures on a system in service.

Rotational unions mentioned in the first paragraph allow a rotating and stationary portions share hydraulic power. The union lets a hydraulic pump in the nacelle direct pressurized fluid to the hydraulic cylinders in the rotating hub, to pitch the blades, for example.

Windpower Engineering & Development

The Parker Catalog 4400 is printed with mobile Quick Response (QR) codes - 2D barcodes - that link users to additional content such as crimper training videos and the new ParkerStore Onsite Mobile Work Container Program.

A recent version of Hose Products Division Catalog 4400 is now available from Parker Hannifin Corporation, the global leader in motion and control technologies. The up-to-date guide is the fluid power professional’s single best resource for product information and installation assistance for Parker hydraulic hoses, fittings, equipment, accessories and technical information.

From the Parker Tracking System to the HoseFinder mobile app, Catalog 4400 brings the latest Hose Products Division innovations to users in a five-tab, easy-to-navigate manual. It  separated into an Introduction, Hose, Fittings, Equipment, Accessories and Technical information. The glossy, 400+-page catalog is three-hole punched for easy binder storage and is available immediately to all Parker customers and distributors.

The Hose section has been redesigned to include extended detail about each hose such as specifications, applicable markets, and applications. Complete dimension data is also listed for all of Parker’s hose and fitting offerings. Technical sections include the most current chemical compatibility charts, as well as diagrams demonstrating proper hose routing, and for identifying fittings.

Catalog 4400 is printed with mobile Quick Response (QR) codes – 2D barcodes – that link users to additional content such as crimper training videos, the new ParkerStore Onsite Mobile Work Container Program and further product details, which can be accessed by scanning the QR image with a smart phone.

Abbreviated Hose Products Division information is also available as a Quick Reference Guide (Bulletin 4400-B13) or Wall Chart. The Quick Reference Guide is an eight-panel foldout directory to Parker’s hydraulic, Push-Lok, suction and return, transportation and refrigerant hoses, as well as specialized hoses for low-temperature, ground support and alternative/marine applications. The Wall Chart includes Parker’s complete line of hoses in a large, easy-to-read poster format for fluid power professionals.

Additionally, updated Wall Charts for the Parkrimp No-Skive 43 Series and 77 Series Crimp Fittings are available immediately for quick and easy hose assembly end connection selection.

Parker Hose Products Division
www.parkerhose.com

Windpower Engineering & Development

Ameriloc
www.ameriloc.com

Windpower Engineering & Development

For hydraulic pitch adjustment of wind turbines, Liebherr supplies not only cylinders, but also the matching large diameter bearings.

German company Liebherr is offering their hydrau-lic cylinder for hydraulic pitch adjustment in wind turbines to the American market. The company offerso both electromechanical pitch adjustment with gearboxes as well as hydraulic pitch adjustment with the corresponding blade bearings as a full system. Cylinders are supplied in accordance with a customer’s particular requirements, in-cluding piston rod heads and integrated stroke measuring systems.

The cylinder fits perfectly to a large diameter bearing of 2,100 mm in diame-ter, typical for a 2-MW wind turbine. It has a piston diameter of 125 mm and stroke length of 780 mm, weighing 172 kg including piston rod head.

The company says their hydraulic cylinders are significant because of careful selection of material,  high standard of technical precision of the components, an exactly matched sealing system, and particularly low wear in operation. The manufacturing range for hydraulic cylinders extends to up to 5,000 mm stroke length and 500 mm piston diameter.

Liebherr, though a sys-tem supplier, is able to offer bearings and drive systems, as well as hydraulic cylinders and control technology, from its own development and production resources. In the sector of large bearings for blade and yaw adjustment in wind power systems, Liebherr manufactures four-point bearings in single-row and two-row versions. All these bearings are characterized by top quality and long service life. The range available among drive systems includes multi-stage coaxial planetary gearboxes, which can be flexibly adapted to every customer’s particular requirements. Liebherr drive systems are particularly famous for their reliability, the compact structural design, and the ideal power-to-weight ratio. Electric motors to supplement the drives likewise come from Liebherr’s own development and manufacturing facilities and resources.

There are essentially no limits on the structural size of the drive elements. The product range includes components for supplying wind turbines from 750 kW through to large tur-bines with rated capacities of 7.5 MW, for operation on land as well as for offshore systems.

www.liebherr.com

Windpower Engineering & Development

Before its launch, the company says Turcon M12 was put through its paces in the research lab, undergoing an extensive test program comparing it to best-in-class compounds against important sealing parameters. Turcon M12 was developed by the company in Helsingør, Denmark, and tested in R&D labs in Stuttgart and Fort Wayne, Indiana.

A proprietary polyurethane compound, Zurcon Z25, has all the characteristics of the widely used Zurcon grade Z20 with an elevated operating temperature to 130°C or 270°F. Zurcon Z25 is recommended for hydraulic applications in which high-temperature performance is required due to an improved extrusion resistance and compression set. The material is ideal for use in heavy-duty cylinder sealing applications where it can guarantee a long service life. These include industrial and mobile applications with limited cooling or cylinders exposed to high-temperature painting.

Self-energizing, Zurcon Z25 operates at pressures to 40Mpa or 5,800 psi without a Back-up Ring. It is suitable for use in all hydraulic fluids and has a low compression set. It has an MDI (diphenylmethane diisocyanate) material base and is also suitable for rotary applications such as swivel joints, where heat is generated by high pressures and low speeds.

Trelleborg Sealing Solutions has also developed Turcon M12, a PTFE based sealing material for key hydraulic sealing characteristics such as friction, wear and high-pressure operation. Extensive testing has shown that Turcon M12 resists most all media, including a broad range of lubricants, and has outstanding wear resistance and friction characteristics. The cost-effective material also provides extended seal life, as well as a wide operating window in temperature, pressure and velocity. “On almost every parameter it is better than previously recommended compounds—sometimes significantly—or was at least equal to them,” says Trelleborg Sealing Solutions’ Fort Wayne product manager Nancy Getz. Turcon M12 can fit hydraulic applications and meet a more universal range of applications.”

Trelleborg Sealing Solutions
http://www.trelleborg.com/

Windpower Engineering & Development

Valve selection provides a good example of the complexity that comes in just selecting one component. Selecting a proportional hydraulic valve for pitch control is an important task. From a functional viewpoint, valves in turbine hydraulics are not required to do anything unusual. They simply control the flow of fluid to cylinders in response to sensor signals in a fairly straightforward closed-loop servo control circuit.

However, the valves are subject to temperature extremes, high and variable rotational and vibration loads, and long periods between maintenance. Servicing such valves requires the attention of specialized personnel.

In response to the wind industry’s need for more precise control, proportional valves are being equipped with an improved control interface featuring CANbus communication using the CANopen protocol. These electronic controls are packaged to industry IP67 environmental standards to meet the needs of the next generation of wind turbines.

Fittings and hoses should be considered critical components. They are key components in gearbox lubrication, typically an active system with constantly circulating fluids.

Hoses with class-zero leakage do not weep in extreme temperature variations or on cool down, so selecting them eliminates a potential source of fluid loss. Such hoses also promote a safer working environment inside the nacelle by keeping its floor drier and delivering extended service lives.

Premium hoses made with Teflon PTFE are resistant to bulging under pressure, making them a good choice for critical braking circuits. They are also chemically inert which is important in gearbox lubrication circuits.

Color coding these devices helps prevent assembly errors on shop floors, and potentially catastrophic failures on a system in service.

Windpower Engineering & Development

As in other areas of the wind industry, hydraulics engineers are looking for ways to improve turbine operating efficiency while reducing maintenance. This leads to a focus on preventative maintenance, rather than just replacing worn parts with new ones from the OEM. Research is also being conducted toward expanding hydraulics in wind transmission drives.

Ken Rohr with Applied Industrial Technologies explains how reducing maintenance costs and improving operating efficiencies are ways operators can improve their return on investment. “We are seeing companies push the envelope to learn how new technologies can help improve operating efficiencies beyond how the system was originally designed,” he says.

According to Rohr, proactively managing oil contamination and preventive maintenance on fluid power systems help keep turbines in peak operating condition. “Old-school maintenance programs of replacing worn parts with new ones at regularly scheduled intervals is being quickly succeeded by preventive maintenance programs that extend part life, and supplement that with replacement-part strategies that offer equal or better parts at a lower cost,” he explains.

Dheeraj Choudhary of Parker Hannifin’s Renewable Energy Division agrees, saying that combining the power density and weight benefits of hydraulics with electronics can make turbines more reliable and precise. “Sealing and connector technologies allow field replacement and repairs without the use of heavy or welding equipment on-site, and they enhance the life of rotational devices such as bearings, the gearbox, and generator,” he says. Choudhary explains that fluid power plays an important role in turbine gearboxes. For instance, new hydraulic systems cool and condition gearbox oil for lubrication and constantly monitor temperature, pressure, vibration, oil particles, and moisture. This helps reduce downtime, gearbox failure, and expensive repairs.

Groups are also doing research to expand the use of hydraulics in wind power. The Center for Compact and Efficient Fluid Power (CCEFP), a National Science Foundation engineering research center, recently launched several projects related to hydraulic applications in wind. One included a grant to study hydrostatic drives for wind transmissions. Brad Bohlmann, sustainability director for CCEFP explains that engineers are investigating using hydrostatic transmissions (HST) in wind applications. “HSTs have been a dominant choice for off-highway propulsion systems for more than 50 years,” he says. “There are literally millions of HSTs currently in use worldwide in very demanding commercial applications where performance, durability, and reliability are critical. Thus, the technology has a long and successful track record, and the proposed turbine drivetrain technology builds on a legacy of success.”

Using a hydrostatic transmission to create a variable-speed wind turbine has many advantages. NREL studies have shown that a variable-speed wind turbine using a continuously-variable mechanical transmission has the potential to extract more energy from wind than a fixed-speed system. The transmission could also eliminate the gearbox and power electronics required for conventional large turbines. It could even potentially obtain variable rotor speed with reliable and efficient permanent-magnet generators, which would eliminate the need for maintenance-prone slip rings. “Replacing the conventional, gearbox-driven drivetrain in a wind turbine with a hydrostatic transmission has the potential to simultaneously improve reliability and increase system efficiency,” Bohlmann says. “The result would be a lower cost of electricity.”

WPE

Windpower Engineering & Development

The cost of scheduled maintenance for wind turbines has been relatively low.  However, unscheduled maintenance is a completely different story. Until recently the turbine manufacturer’s warranty has covered unscheduled maintenance and repair costs. But that’s changing as a large number of turbines come off warranty and U.S. installations increase.  These trends have triggered demand for turbines with longer-lasting components and warranty periods that extend to seven years—rather than the two to five years most currently offer.

Component Failures
Vibration contributes to hydraulic component failures in wind turbines. Other causes of failure include environmental factors, such as extreme heat and cold, and corrosion in offshore installations. Hydraulic fittings used in a turbine’s many high-pressure hydraulic applications have the ability to overcome these failure modes, though they are often overlooked in the design phase. Typical high-pressure connections are located in pitch, yaw, and braking systems. Fittings are also used in gearbox lubrication systems to transfer fluids for filtration.

Soft-Seal fittings come in a wide variety of types and styles. used in turbines' hydraulid applications, they can allow manuracturers to extend warranty periods.

Causes of leakage in hydraulic systems
The greatest nemesis in wind-turbine design and application is commonly considered to be fluid leakage in hydraulic connections. But what causes leakage is surprising. Four leading contributors and how often they are a factor, include:

• Improper installation, 60%
• Poor system design, 20%
• Quality of components, 15%
• System abuse, 5%

While causes of leakage are identifiable, results can vary significantly. A sure consequence is that any leakage will cost money. Based on a 24-hours-a-day  operation with lubrication oil at $10 per gallon, here’s how a single leak can add up to a sizable expenditure if not corrected:

• 1 drop every 1 minute = 6.7 gallons per year = $67
• 1 drop every 10 seconds = 40 gallons per year = $400
• 1 drop every 5 seconds = 80 gallons per year = $800
• 1 drop every second = 402 gallons per year = $4,020

In addition to fluid loss, many costs associated with leaks are often overlooked. Some of the less visible ones are:

• Energy loss
• Safety hazards
• Maintenance costs
• Warranty issues
• Environmental responsibilities

Design considerations
System design is the first line of defense in leak prevention. It involves selecting the right components for wind turbines to reduce the occurrences of leaks and hydraulic connection failures. For those in the design phase of a turbine hydraulic system, consider these characteristics when selecting hydraulic components:

Application – the wind turbine’s environment will influence fitting design and selection. Protective coatings are usually applied to steel fittings to extend their useful life in corrosive environments. The most common finish for steel fittings is electroplated zinc. It will corrode sacrificially, protecting the steel base metal from normal rusting due to the presence of oxygen, moisture, and acidic gases. Stainless steel is used for highly corrosive environments typically seen in offshore wind installations.

Pressure – What is the minimum and maximum operating pressure seen in the hydraulic system, including potential spikes?
The rated dynamic pressure of the fitting should be equal to or higher than the system pressure. As a general rule, tube fittings are rated at a 4:1 design factor. The design factor is generally applied as a ratio of the materials’ ultimate strength with respect to the dynamic pressure rating of the connection. The 4:1 design factor applies to “normal” operating conditions, with moderate mechanical and hydraulic shocks.  For severe wind turbine vibration and shock operating conditions, a “de-rating factor” should be applied directly to the dynamic pressure of the fitting as shown in the table Severity of Service.

Shock – Will the component be subjected to mechanical or hydraulic shocks that could be detrimental to its expected life?

Vibration – How severe is the vibration? Will it cause the components to loosen or fail prematurely?

Temperature (ambient and fluid) – What extremes will the system be subjected to? How will they affect component materials?
The operating temperature range for tube fittings depends on the material, plating, and seal. Temperature ranges for both the fitting and seal material are given in the table Material temperatures for fittings and seals.

Environment – Where will the system be operating? How will the location affect its performance? Will there be excessive corrosive or mechanical abuse?

Contamination – Are contaminants introduced to the system through the style or quality of the fitting selection?

Fluid velocities – Does the tube and fitting size allow for acceptable velocity?

Size – the tube O.D. and wall thickness must be considered for all tube fittings. With most tube ends, there are limitations with respect to the tube and wall thickness. Other selection factors include system pressure, flow, temperature, and the service environment.

Media – the type of fluid being conveyed is important, and must be considered when selecting the fitting material and seal.

Soft O-ring leak-free fittings prevent vibration failure
Many recent industrial and wind turbine systems use metal-to-metal sealing methods in their hydraulic connections. The standard metal-to-metal fitting used in wind turbines is the metric 24° flareless, DIN 2353 style. Using soft-seal fittings versus traditional metal-sealing fittings lets manufacturers extend warranty periods in turbine hydraulic systems by reducing the possibility of improper installation and fatigue failures. Additionally, soft-sealing hydraulic fittings have high-pressure capabilities, up to 11,000 psi (758.4 bars) as a standard working pressure.

Metric 24° bite-type DIN 2353 are the standard metal-to-metal fittings used in wind turbines. However, using soft-seal fittings instead helps reduce the chance of improper installation and fatigue failures.

The two soft-sealing hydraulic fittings applicable to the wind industry are metric 24° flareless O-ring (DIN 2353) and the inch sized O-ring face seal (SAE J1453). These fittings use an elastomeric seal that makes contact to seal the threads during fitting installation.

The soft O-ring face seals can eliminate leaks in high-pressure hydraulic systems—despite severe mechanical shocks and vibration. The fitting has a body, tube nut, sleeve, and O-ring. The O-ring soft seal sits in a groove in the fittings flat face. The sleeve permanently attaches to the tube either mechanically (by flanging) or by brazing.

As the nut tightens to the fitting body, the O-ring compresses between the body and flat face of the tube flange (or braze sleeve) to form a tight seal. The result is a more-reliable seal than possible with traditional metal-to-metal connections—though it comes with more restrictive media and temperature limitations. O-ring soft-face, seal-tube fittings can stop leakage in hydraulic connections up to a maximum of 11,000 psi (758.4 bars) under constant vibration and mechanical shock.

An exploded view of an O-ring face seal fitting. Soft O-ring face seals help eliminate leaks in hydraulic systems, despite severe shocks and vibration.

Compared with traditional bite technology, EO-2 O-ring soft-face seals (90 durometer) offer the following benefits versus bite fittings for wind turbine applications subject to constant vibration and mechanical shock:

• Soft elastomeric seal
• High degree of fine sealing – proven up to 11,000 psi (758.4 bars)
• Long-term reliability without re-tightening
• No air ingress
• Easy assembly check
• Unlimited repeated assembly
• Seal can be individually replaced
• Minimal possibility of over tightening the nut during assembly
• Long history of product effectiveness

The temperature range for soft-seal O-rings depends on the seal material. Nitrile is most common and typically has a range of –30 to 250°F (-34 to 121.1 °C). Fluorocarbon O-rings handle temperatures to 400°F (204.4°C), while other materials suit various fluids and temperatures.

O-ring fitting/tube assemblies offer a more reliable seal (left - braze end; right - flange end) than possible with traditional metal-to-metal connections.

Non-welded, leak-free pipe connections
For reliable leak-free wind turbine piping systems larger than 2-in. (50.8 mm), Parker’s Parflange F37 system (Figure 5) is a suitable alternative to time-consuming and costly welding. It lets engineers quickly make hydraulic pipe connections that are sufficiently robust for heavy-duty wind turbine applications.

The system uses two connection technologies for leak-free, weld-less connections: F37 flare and F37 retaining ring. The flare system provides a smooth, clean, high-strength flared tube end fitted with a seal carrier insert. For higher-pressure systems, a retaining ring holds the flange along with a highly engineered seal carrier for leak-free performance

Parker’s Parflange F37 technology lets engineers quickly make non-welded pipe connections robust enough for use in wind turbines.

Performance benefits include:

• Complete pre-engineered piping
• Reduced dependence on welded piping
• Fully heat code traceable
• Reduced system flushing time
• Pressure capabilities to 6,000 psi (420 bar)
• Reduced concerns of stress-corrosion cracking of welded joints
• Compliant with ISO 6162-1/-2, ISO 6164 (dimensions & flange patterns)
• DNS and ABS approved

To sum up
These high-pressure fitting systems (soft-seal O-ring and F37 non-welded flange assembly) are used in all fields of hydraulic applications. A wide range of designs and materials makes them particularly suitable for wind applications where safety, corrosion-resistant leak-free connections, and ease of assembly are important factors. The fittings can also play a significant role in designs that call for longer-lasting components and extended warranty periods.

Windpower Engineering & Development