Sewer maintenance tools now include special cameras and milling robots, such as the ones from BRM GmbH, Biebergemünd, Germany, says Günter Meister, managing director. The camera provides a first visual inspection of the sewer pipes. “The camera head—our own design—can be swiveled 270° horizontally and 400° radially,” Meister said. “This ensures that the specialists are able to inspect the pipe walls in minute detail, and determine any damage.”

Once the initial inspection has taken place, the small but powerful milling robot starts its work. The rotating milling head, with its diamond-studded surface, devours ingrown tree roots, broken-off pipe splinters and hardened, encrusted muck, thus removing any blockages in the pipes. The milling robot consists of a two-axle trolley to move the robot forward and back inside the pipe. Two hydraulic cylinders are fitted to the trolley. They tip the milling arm up and down or forward and back. The control electronics are also fitted to the trolley.

BRM’s milling robot F170, which uses customized air motors to deliver high power in adverse conditions. Photo courtesy of BRM.

A flange-mounted circle gear turns the milling arm, and the air motor is carried on the milling arm itself. This motor supplies the power for the milling work and causes the milling head to rotate. At the command console the operator manipulates joysticks and switches to control the milling robot. The special camera fitted to the milling arm monitors the work underground and transmits the images to a monitor. It means that the specialists are constantly able to monitor the progress of the cleaning work.

BRM GmbH supplies two different sizes of milling robot—the F130 for DN150 to DN300 pipe widths, and the F170 for DN200 to DN600 pipes. And now, the larger milling robot is available with even more power, thanks to a new air motor from DEPRAG Schulz GmbH, Lewisville, Texas, which gives the F170 twice the power.

BRM’s milling robot F170 entering a sewage tunnel. Photo courtesy of BRM.

According to application technician Sven Menzel at sewer maintenance company GM-San UG, the output is much higher than the previous design. “On a project with 35 branch pipes, we previously required 1050 working minutes to carry out the job. With this new air motor we had completed the work after just 525 minutes. That is an enormous saving in time and operating costs.”

DEPRAG, which specializes in customizing its line of air motors for different applications, supplied an air vane motor from its Individual Line onto the milling arm of the robot.

After testing several air motor designs, BRM’s Meister said that no other air motor achieved such high removal rates.

The air motor, which has been specifically developed for use in the milling robot, has a square housing. The power pack is 145 mm long and 70 mm wide, so is ideal for small, tight spaces. It occupies just a third of the size and has a fifth of the mass of a comparable electric motor.

Air vane motors operate on a very simple principle: The compressed air—generated by a compressor—causes the air motor to rotate. In air vane motors, the rotor—which rotates inside an eccentric cylinder—is set into motion. Vanes are inserted into the slots of the rotor and the centrifugal force that arises presses them outwards. This creates work chambers for the expanding compressed air. With this expansion the compressed air that feeds through converts the pressure energy into kinetic energy—causing rotational motion. Air motors can operate optimally within a wide range of changing loads, because the power output remains almost constant over a wide speed range. Motor power is adjusted by changing the operating pressure, while speed is controlled by smoothly throttling the air quantity.

Milling robot F170 getting ready to clear out a sewage tunnel. Photo courtesy of BRM

The air motor can cope with a variety of workloads. Meister added,  “If the milling head encounters what appears to be an indestructible obstacle and comes to a standstill, it suffers no damage. In the event of overload the air motor simply stops, and once the load abates it starts up again immediately. And this can happen over and over again even for extended operating cycles. In short, it is the ideal drive for our milling robots. This air motor cannot overload and suffer damage.”

To counter the adverse conditions of wet, aggressive contamination inside the sewer pipe this pneumatic drive is coated with an anti-corrosion protective coating. Additionally, before the milling robot descends into the sewer system, the air motor is charged with compressed air, meaning that moisture and contaminating particles cannot penetrate into the internal overpressure of the unit, because the air motor more or less “seals” itself, making it resistant to all types of contamination inside sewer pipes.

After the milling robot has cleared the pipes of muck and ingrown tree roots, and sewer inlets and outlets are sealed up, defective sections of pipe are refurbished rather than replaced. They are lined from inside with prepared special film tubes called inliners, thus sealing them from any potential leaks. Then, the milling robot is deployed a second time. A ball-head is used to ensure that the inlets and outlets are now properly reopened.

Applications technician Sven Menzel of GM-San UG concluded, “With the F170 and the new DEPRAG air motor the work involved in opening the branch-outs is much faster.”

DEPRAG Schulz GmbH & Co

www.deprag.com

BRM GmbH

www.BRMGmbH.de 

Pneumatic Tips

Question: We have a new maintenance supervisor that has turned down our shop air pressure to 86 psi, supposedly saving operating cost. My opinion is it should be set between 90 and 100 psi to accommodate surges. Is there really a significant savings by turning the supply down to 86 psi?

-A concerned electrical controls programmer

Answer:

Dear Concerned,

Yes indeed, lowering discharge pressure reduces the compressor motor power by about 1% for every 2 psi of lower pressure. Also, the lower pressure makes any unregulated uses in the ”shop” reduce consumption (cfm) by almost 1% for every one psi of pressure reduction. You will achieve extra savings if your compressor control systems can turn down compressor power in response to reduced flow or unload and possibly shut off unnecessary compressors.

The best pressure at which to set your system is the level your production can operate efficiently and effectively without waste; there is no right pressure, it depends on your machines. That being said, often you may have 90 to 100 psig at the compressor, but at the production machine, where the actual work is being done. you could have only 65 to 70 psig. In some cases, it may be even lower due to pressure drops in undersized piping, filters, regulators, lubricators and tubing and connectors. The goal is to lower compressor discharge pressure, without affecting the end users. The method is to address these pressure differentials and get the pressure to the machines with minimal loss; then the compressor discharge pressure may be reduced even more. This is typically a job for a controls programmer like you.

Having artificially high plant pressure can help you deal with surges in compressed air demand that might occasionally cause low pressure and affect production. The higher pressure acts to store reserve air in the various volumes made up of receivers, pipes and such in your system. However, the higher pressure costs more to produce and makes unregulated end uses consume more air, which is an expensive trade off. Another strategy might be to use a pressure/flow controller and large storage receiver capacity in the compressor room. This will supply stored air for surges, but maintain lower plant pressures to reduce artificial demand caused by elevated pressures. Your compressed air service provider can assist with implementing this.

If you want to learn more about optimizing your system download the free resource “Improving Compressed Air Performance: A Sourcebook for Industry” written by the Compressed Air Challenge and the Department of Energy. Also check out the Compressed Air Best Practices Manual.

You may be interested in learning more in the Compressed Air Challenge’s upcoming November 5th webinar on compressed air Fundamentals seminar—or the many in-person seminars across the country.

By Ron Marshall for the Compressed Air Challenge.

Pneumatic Tips

Throughout the years I’ve learned about the hydraulics that gave the power density to The Top Thrill Dragster; the pneumatics that gave the Skyhawk its lift; and the linear synchronous motors that drive the Maverick roller coaster. So it was a no-brainer for me to touch base with the amusement park’s Corporate Vice President, Safety and Engineering Monty Jasper, to learn what type of technology was used on Cedar Point’s newest record breaker — the GateKeeper.

According to Cedar Point, the GateKeeper is the tallest, faster and longest wing coaster in the world, with its first hill climbing to 170 ft, then flying through two giant keyhole towers.

Cedar Point’s GateKeeper roller coaster uses pneumatic brakes to ensure safety.

I was a little disappointed that the ride didn’t use fluid power to propel it up its hills as I’d hoped, but did learn something new: I found that like most coasters, it uses pneumatic brakes to safely stop the ride. When I asked Jasper why, he said it’s because pneumatics are “inexpensive, proven and reliable.”

These words are pretty standard when it comes to users of pneumatics. As long as you maintain your compressed air systems, ensuring they are leak-free and running at their highest levels of efficiency, they are truly cost-effective, reliable systems that have proven their usefulness over many decades.

Although some roller coasters at Cedar Point use magnetic brakes, pneumatic brakes are still popular on the tracks. Simply engaging a pneumatic cylinder raises the brake, which in turn slows down the train. Having more than one set of pneumatic actuator brakes makes the braking fail-safe and redundant. And each set of brakes has its own air supply system in case of power supply failure. Check out Cedar Point’s video on their YouTube channel to see the coaster being tested, with the smooth braking action seen at the end.

Simple, effective and safe. That’s the power of pneumatics.

Pneumatic Tips

Compared to the market standard, Rexroth has halved the weight of the new valves by using resistant high-performance polymers and reducing the number of parts. A further plus: The required space has also been cut by 45 percent. Developers arranged the valve components at an angle and optimized the supply and exhaust channels, thus reducing flow losses. Users profit from a flow improvement of 40 percent, allowing them to substantially lower the supply pressure and boosting their energy efficiency.

The new valve system also fulfills engineers’ demands for customized automation solutions. With 25-pin D-sub connection, manifolds can be configured in increments of 1 after the second valve position, and after the fourth valve position with 44-pin D-sub and Field bus connections.

The new AV03 can control up to 24 coils with 25-pin D-sub connection, up to 40 coils with 44-pin D-sub connection, and up to 128 coils with Field bus connection. Nowadays, more and more users also implement different pressure zones in a single valve system to achieve further savings. The new valve systems allow up to ten supply plates for this exact purpose.

In addition to improving the energy efficiency, the new AV03 also fulfills expectations for simple engineering. Users can connect the valve systems electrically using multipole or fieldbus connections, with integrated I/O modules, depending on their configuration. Thanks to the option of directly connecting sensors to the valve electronics, fewer cables have to be fed back to the control cabinet.

Find further information on the valve system.

Bosch Rexroth
www.boschrexroth-us.com

Pneumatic Tips

EXAIR
www.exair.com

Pneumatic Tips

The MR Series is designed to be a drop-in form, fit, and function replacement for magnetostrictive sensors but with much more robust construction and a lower cost of ownership, specifically targeting port-mounted applications of industrial, mobile, or subsea hydraulic cylinders and large pneumatic actuators. MR Series sensors are based on a patented contactless inductive sensing technology that employs a solid probe construction style which requires only a simple conductive tubular target or a small diameter deep hole gun drilled in the cylinder rod for operation rather than needing a permanent magnet ring or some other type of special target.

Because these sensors use a simple coil design rather than “time-of-flight” technology, the MR Series sensors can withstand intense shocks and vibration, and operating temperatures up to 85 C for standard products and 125 C for custom units. Resembling a magnetostrictive sensor with its sensor head and male o-ring port threads, an MR sensor  has a shorter stroke-to-probe length ratio and can thread into the same o-ring bosses (either SAE J1926-8 or ISO 6149-1 M18) that accept a magnetostrictive sensor.  For those applications where an MR is replacing an existing magnetostrictive sensor, the magnet ring can usually be left in place without affecting the performance of the sensor.

MR Linear Position Sensors are available in full ranges from 2 inches to 36 inches (50 mm to 900 mm) with either an analog DC voltage or current output, a linearity error of less than or equal to ±0.1% of Full Scale Output, and a -3dB frequency response of 500 Hz.  Being contactless, MR Series sensors are not subject to wear and show no output signal deterioration over the life of the sensors. The probes are offered in diameters of 7 mm (MR-7) for industrial use and 11 mm (MR-11) for heavier duty or larger cylinder applications. The MR Series comes standard with a 4-pin M-12 connector or 5-pin DIN connector, or with a 4-conductor cable, but other connectors and cable options are available.

The IP-67 sealed housing uses no trimmer pots for setting Zero and Full Scale.  Instead, ASG’s proprietary SenSet™ calibration feature permits the user to match the analog output of the sensor to the motion of the actuator or cylinder on a stand-alone basis rather than the user having to scale the sensor’s basic output in an associated control system.

Alliance Sensors Group
www.alliancesensors.com

Pneumatic Tips

Andrew Duguay, Institute for Trend Research (ITR)
Mr. Duguay will provide insights into the latest economic developments & future trends for the U.S. and global economy and its effects on the fluid power industry.

If you have any questions, please contact Eric Armstrong at 414-778-3372 or email earmstrong@nfpa.com.

To register, please click HERE.

Pneumatic Tips

The VR24Z range of 3/2 way solenoid operated poppet valves is suitable for compressed air systems that require a dedicated valve and cylinder to engage and disengage an electrical connector.  Typical installations of this kind include cam shaft connectors, line breaker connectors, vacuum and air blast circuit breakers and shoe gear controls.

Developed specifically for the rail industry, the VR24Z range delivers Engineering Advantage through exceptional reliability and safety credentials, and has been designed to withstand the most extreme environmental conditions.  Functioning in temperatures ranging from -40ºC to 80ºC, the circuit breaker solenoid valves have also been shock and vibration tested to EN61373 Category 1 class A and B. The valve is suitable for retrofit as well as OE installation and is available with a short lead time.

Protected by a robust and lightweight aluminium housing, the valves come with customisable flange mountings for fixing holes and air connections, making installation both flexible and straightforward.  For easier maintenance, the valves are available with a manual override feature, which allows the solenoid valves to be shifted when the coil force is not available due to loss of power or coil failure.

The VR24Z circuit breaker solenoid valves have an operating pressure of up to 10 bar (145 PSI), and are designed for systems generating flow of up to 340 l/min.  The valves are available in 24 VDC, 36 VDC, 72 VDC and 110 VDC variations.

Norgren
www.norgren.com

Pneumatic Tips

• Turn on more pumps
• Buy a really big pump
• Fix the leaks

When it comes to compressed air leaks, it is surprising how many people choose the first two options to solve their problems, at a huge financial penalty in terms of ongoing operating costs and the equipment budgets.

Participants of the Compressed Air Challenge Fundamentals of Compressed Air Systems seminar, also available as a webinar, learn about the high cost of producing compressed air and the inherent inefficiencies in the compressor room. Understanding the supply side of the system is important, but more important is first looking at compressed air demand, including leaks.

Leaks can be a significant source of wasted energy in an industrial compressed air system, sometimes wasting 20-30% of a compressor’s output. A typical plant that has not been well maintained will likely have a leak rate equal to 30% of total compressed air production capacity or higher. On the other hand, proactive leak detection and repair can reduce leaks to less than 10%.

In addition to wasting energy, leaks can also contribute to other operating losses. Leaks cause a drop in system pressure, which can make air tools function less efficiently, adversely affecting production. In addition, by forcing the equipment to cycle more frequently, leaks shorten the life of almost all system equipment (including the compressor package itself). Increased running time can also lead to additional maintenance requirements and increased unscheduled downtime. Finally, leaks can lead to adding unnecessary compressor capacity.

How to fix leaks
Leaks occur most often at joints and connections at end-use applications. Stopping leaks can be as simple as tightening a connection or as complex as replacing faulty equipment such as couplings, fittings, pipe sections, hoses, joints, drains, and traps. In many cases leaks are caused by bad or improperly applied thread sealant. Select high quality fittings, disconnects, hose, tubing, and install them properly with appropriate thread sealant.

Non-operating equipment can be an additional source of leaks. Equipment no longer in use should be isolated with a valve in the distribution system.

Establishing a leak prevention program
A good leak prevention program will include the following components: identification (including tagging), tracking, repair, verification, and employee involvement. All facilities with compressed air systems should establish an aggressive leak reduction program. A cross-cutting team involving decision-making representatives from production should be formed.

A good compressed air system leak repair program is very important in maintaining the efficiency, reliability, stability and cost effectiveness of any compressed air system.

Compressed Air Challenge has a wealth of information on leaks and other related issues available for download at our website library. Also available at our bookstore.is our “Best Practices for Compressed Air Systems”.

By Ron Marshall, for the Compressed Air Challenge

Pneumatic Tips

For more than 100 years DXP Enterprises, Inc. has served a spectrum of industries including: manufacturing; oil and gas; and food and beverage processing. They also offer engineering and fabrication services as well as service and repair. DXP Enterprises, Inc. will aid Norgren in reaching industrial maintenance, repair, operation and production (MROP) customers in the South Atlantic states of Florida, Georgia, North Carolina and South Carolina.

DXP Enterprises, Inc. boasts excellence in the fluid power arena and offers certified specialists as well as repair, fabrication and warranty services.

Norgren
www.norgren.com

DXP Enterprises, Inc.
www.dxpe.com

Pneumatic Tips