October 2020 Design Notes

In hydraulic systems, the actuator, typically one cylinder, must exhibit smoothstart acceleration to be able to guarantee safety, comfort and extreme durability. No one wants to sit in an excavator and move the joystick only to watch the boom shoot forward at full speed, scaring those working nearby, jolting the excavator driver and, what’s more, placing unnecessary strain on the mechanics. In fact, it is imperative that even an unexperienced driver can work in a controlled, precise and, at the same time, comfortable manner. MINIMESS Minivalv by Hydrotechnik is an effective, economical and easy-to-integrate solution for this.

Hydrotechnik’s MINIMESS Minivalv is a throttle check valve that restricts the flow rate through a notch or hole in one direction and, in the other direction, releases it without restriction.

Complex controls and servovalves make it possible to control the movements of an actuator in any possible way and to optimize them for every situation. However, if yours is a cost-sensitive market segment and you want to use conventional directional valves with a hydraulic joystick, MINIMESS Minivalv offers an ideal alternative.

MINIMESS Minivalv is a throttle check valve that restricts the flow rate through a notch or hole in one direction and, in the other direction, releases it without restriction. It can be mechanically preloaded if desired. It is typically integrated in the hydraulic pre-control line with throttle where the directional valve terminates and ensures that the valve piston is somewhat restricted in its movement from or into neutral position. In contrast to a simple throttle, the return valve’s design ensures that negative pressure does not build up during the supply process.

Minivalv can be integrated in the pre-control line for rotation of the cab of the Volvo Construction Equipment ECR50D mini digger.

Depending on the desired degree of throttling, either a hole in or a notch on the valve piston is used to show the throttle cross-section. Preferably, the notched valve piston is used when throttle cross-sections are very small. This has the advantage that it is easy to flush out any dirt particles that collect in the notch when the flow direction is reversed. The more economical bored valve pistons are used when cross-sections are larger.

MINIMESS Minivalv is known for its compact design. It is the size of a customary male connector and can therefore be integrated without additional effort. It is suitable for system pressures up to 400 bar. Mechanical connections, the size of the orifice or notch and the pre-load or cross-section are adapted to the requirements of the application.

MINIMESS Minivalv is known for its compact design. It is the size of a customary male connector and can be integrated without additional effort.

Typical applications include switch speed limitation of excavator booms, excavator bucket movement or the rotation of the cab as well as the optimization of the pre-control of counter-balance valves. The image shows how Minivalv can be integrated in the pre-control line for rotation of the cab of the Volvo Construction Equipment ECR50D mini digger.

Hydrotechnik GmbH | hydrotechnik.com

Smart hydraulic actuators simplify hydroform tube processing upgrade

In this before and after shot, one sees the mess of the hydroforming line compared to the new system using Kyntronics smart hydraulic actuators with in-line configuration.

A chassis system manufacturer needed to retool a Tier-1 automotive hydroforming line to accommodate a new model design change. The new line required the flexibility to produce both the current OEM product and the new product at higher volumes. As a requirement for the new machine design, the manufacturer wanted to eliminate the messy and inefficient hydraulic system used in the old machine and implement new technology that provided better process control, was cleaner, quieter, saved energy and had the flexibility to handle the part variability. In addition, the new system would need to seamlessly integrate with Rockwell Automation controls and drives.

The manufacturer considered using electro-mechanical actuators but found that the large size and high cost of EMA technology would not meet their project requirements. Instead, the manufacturer chose 16 Kyntronics Smart Hydraulic Actuators (SHA). The SHAs were rated from 6,000 to 23,000 lb-ft (27 to 103 kN) of force and were provided in both in-line and right-angle configurations to optimally fit the available space envelope. The SHAs incorporated Rockwell Automation (Allen Bradley) servomotors and drives that met the customer’s control specifications.

Kyntronics smart hydraulic actuators with right-angle configuration compared to the inefficient system.

The Kyntronics SHAs implemented on the new hydroform tube processing machine exceeded the requirements of the machine builder and end customer including the following highlights:

• The SHAs eliminated the space-consuming HPU, manifolds, valves and hoses which helped contribute to the machine footprint being 50% smaller than the previous production line.

• The ability of the SHAs to operate independently with cycle overlap allowed the new machine to produce 25% more parts per shift versus the previous machine.

• The programmability of the SHAs provides flexibility to handle multiple part variations with improved process control – using position and force control to ensure optimal cycle times.

• Elimination of the hydraulics on the new machine results in an environment that is cleaner, less noisy and more energy efficient.

The Kyntronics SHA combines the power of hydraulics with the precision of servo control resulting in an ideal solution for the hydroform tube processing machine.

Kyntronics | kyntronics.com

Regenerative dryer reduces costs, increases performance of dust collector system

Suburban Manufacturing’s Tsunami Tank-Mounted Regenerative Air Dryer

Dust collector systems play a critical role in maintaining compressed air cleanliness for manufacturers. Plant operators are always looking for any incremental advantage to improve pulse jet cleaning in bag (sock) or reverse flow cartridge systems. This is because even the slightest improvement in dust cake contaminate removal can create a costimproving ripple effect throughout the system by increasing bag life and reducing compressed air consumption (CFM) through less frequent pulsing.

What if engineers, plant managers, and operators have been missing the key component to radically improve system effectiveness all along? What if there was a total solution available to optimize and protect the entire process? Suburban Manufacturing’s Tsunami Tank-Mounted Regenerative Air Dryer is revolutionizing how manufacturers maintain their dust collector systems for absolute performance at minimal costs.

The challenge faced in every dust collector application is to maximize pulse effectiveness and extend bag life, while minimizing energy consumption in the form of compressed air. The system is optimal when the pulse interval effectively removes dust cake to the point where the filter life meets or exceeds the manufacturers’ specification. Unfortunately, this scenario very rarely occurs, if ever.

While advancements in pulse valves, filter bags (socks), and pressure differential controllers show supporting data that doctor efficiencies in collector performance, this technology focuses on an incumbent enemy, that if corrected, will dramatically extend the life of all system componentry. Because dust collectors consume less than 30 cfm, on average, operators typically pay little attention to the quality of compressed air being supplied. Even though these collectors have low flow specifications, measured in cfm, the actual volume of air per pulse dramatically exceeds that specification.

What happens to this high volume of air as it rapidly exhausts out the orifice of a pulse valve is the underlying issue termed supercooling — this is what Tsunami addresses with its bag house drying technology.

Supercooling explains the rapid expansion of air that loses heat due to the immediate separation of molecules. Simply put, for every 20°F that air cools, it loses approximately 50% of its ability to hold moisture in the form of vapor, or humidity. In collector applications, this cooling effect converts water vapor to liquid as air quickly expands out of each pulse valve. Damp air hits the bags or elements creating a wet cake substance that prematurely clogs the filter and inhibits air from passing through. Not only does this wet air reduce the life of each filter, it also wreaks havoc on collector systems in climates where freezing may occur.

Having excess storage of ultra-dry air in dust collector applications is necessary for eliminating moisture within the system and increases the life and efficiency on the system.

Tsunami Compressed Air Solutions has designed an all-in-one regenerative air dryer to eliminate air-related issues that prevent a dust collector system from operating proficiently. Let’s examine how the system works.

Air travels into the zero-maintenance water separator where water is removed and particles are filtered down to 10 micron. Before exiting the pre-filters, the oil coalescing element removes aerosols down to 0.001 ppm and particulates down to 0.01 micron.

A gate valve and flow meter, integrated before the inlet of the dryer, help prevent the collector from overrunning the system.

Pretreated air enters the regenerative dryer where dew points and relative humidity are lowered down to –40° F and 0.01% RH. The technology features self-regenerating towers to eliminate the need for manually changing desiccant. This level of air quality prevents the chance of moisture creation during the supercooling process.

A small amount of dry air is reverse-flowed to purge out the humid desiccant while the bulk of the air is stored in an 80-gal receiver tank. This excess storage of ultra clean, dry air is essential to supply the high surges of flow experienced during pulsing. To accommodate for these spikes in demand, a high-flow regulator is utilized on the tank outlet port.

If monitoring compressed air quality is desired, a test port is located on the inlet side of the receiver tank.

In one example, a tank-mounted regenerative dryer was installed at a tire plant and then monitored by use of a data logger. The goal of the installation was to reduce the air consumption and improve bag life. Dust collectors were filtering carbon black and the pulse valves cycled off a photohelic pressure switch that unintentionally robbed the plant’s air capacity.

After just days of being installed, it was discovered that by using dry air with at least a –40° F dew point, the pulse valves cleaned the bags more effectively, and cycled 50% less often than before the dryer was installed.

The included chart shows the data logger that was used to capture air consumption during the study. The dust collector dryer reduced the amount of air/pulses considerably. The facilities engineer stated that the effectiveness of each pulse extended the filter life by two times and estimated the return on investment to be about three months.

Suburban Manufacturing | gosuburban.com