Energy Conservation

4 Applications that Benefit from LCP DX-Based Liquid Cooling

Guest Contributor, Herb Villa, Rittal

Liquid cooling of IT equipment, now at the row level instead of for an entire white space, is gaining momentum in the distributed data center world, where the demand for efficiency in cooling higher density racks is making IT professionals rethink their reliance on traditional methods. Various liquid cooling technologies – direct-to-chip, immersion, direct expansion and others – are winning favor in the different IT spaces. Why? Because they bring heat removal closer to the equipment, require little if any changes to infrastructure, and are easy to scale as demand grows; when you need to add more racks, additional cooling capacity is achieved with the cooling systems supporting increased IT enclosures.

Liquid cooling is especially advantageous for small and medium-sized businesses that have on-premise servers mounted in one or more enclosures. Many of the IT professionals supporting these organizations are forced to put these in some remote, out-of-the-way space within the building, assuming (wrongly) that as long as the building’s HVAC system has a vent terminating in that room, cooling the equipment won’t be a problem.

But we’ve seen that “comfort cooling,” which is the job of a facility’s HVAC system, isn’t adequate for server rack cooling and the demands of heat-generating IT equipment. Those demands are non-negotiable: precise temperature and humidity control, and proper airflow to get the heat away from the equipment.

Focusing on just a few different market sectors can illustrate the demands of the new IT environment. Hospital & healthcare, schools, factory floor, distribution centers are all examples of the types of organizations and facilities often forced to utilize spaces never intended to support the climate control needs of IT equipment: unused offices, janitors’ closets, corners of basements, etc. And because all rely on data to run their businesses, they’re all at risk of system failure because they aren’t addressing the critical climate needs of their IT investments.

Enclosure Climate Control in Hospitals

Data is critical in ensuring quality patient care and the smooth, efficient performance of even the smallest healthcare facilities. Hospitals, clinics and physician practice groups rely on IT equipment to store and transfer data among departments, achieve operational efficiency and maintain compliance using enterprise resource planning (ERP) systems. Without proper temperature, humidity and airflow control, the IT equipment that processes and stores necessary data could fail, and the cost of downtime and potential lost data is immeasurable.  There is also extremely limited space to place these systems; after all, the main business of a hospital is patient care, not IT.  Especially today in the midst of a global pandemic, healthcare facilities must maximize space for their patients, not their IT appliances.

Data Center Cooling in Education/School Campuses

What happens when a school’s “comfort cooling” system can’t keep up with all the heat being generated by the server room’s IT equipment (if they are lucky enough to even have such a space)? These systems are intended to keep humans comfortable, not maintain the precision and optimal air flow needed to remove heat generated by the IT equipment. Schools rely on IT equipment to help maintain productivity, organize data, and reduce time and effort of work that would otherwise be manual. Servers and processors enable insights that help administrators allocate the right resources to the right areas at the right time, connect campuses and departments, and speed communication between students, teachers, administrators and parents. And as with the healthcare sector, COVID-19 has placed enormous demands on bandwidth and compute capability as school systems have become virtual classrooms supporting remote learning applications and programs. This means more equipment, more heat, and less available installation space.

Server Rack Cooling in Manufacturing

Manufacturing facilities represent some of the most uncontrolled environments in which to place IT equipment. Wide temperature ranges, dust, debris, moisture and corrosive elements are all enemies of smooth factory floor operations, and because there is often no dedicated IT room (or at least one designed for IT), the risk of equipment degradation and failure is very real. Manufacturing organizations rely heavily on manufacturing execution systems (MES) and ERP systems for visibility into all aspects of the supply chain and production, and for seamless integration between the shop floor and Billing, Sales, Operations, HR and other departments.

Climate Control Units in Distribution

Distribution warehouses are notorious for having subpar climate control: they’re often either too hot or too cold; when air conditioning is running, cold air is “dumped” to the floor and doesn’t mix with warmer air near the ceiling (and the opposite situation when the heat is running); air flow throughout the building is almost impossible to control; and air leaks from the inside to outside and vice versa are common. Imagine, then, the effect of a poorly controlled climate in a small room where heat is being generated.

Like manufacturing, warehousing and distribution rely on up-to-date information about inventory, customers (through a CRM tool), fleet management, marketing, shipping and more. When equipment is compromised by temperatures that are too high (and in some cases too cold), all the data that’s used to ensure optimum facility and system performance is at risk for failure.

The best solution for cooling racks for these types of organizations is one that’s similar to a building’s own AC – one that uses direct expansion (DX). Heat removal is achieved with a compressor / condenser refrigeration cycle to reach and maintain a setpoint temperature and humidity level but that is designed to work at the cabinet (sometimes called enclosure) level.

Rittal’s DX-based solution (part of the Liquid Cooling [LCP] family of products) is ideal for businesses, like those above, that have “mission-critical” data needs but less-than-ideal data room options. The close coupled LCP DX 20kW provides a single or multiple IT enclosures with up to 20kW heat removal capacity, available in both closed loop rack and open loop inline options. Some of the benefits of this solution include:

  • A small footprint, making it appropriate for nearly any location within the building
  • Precise temperature and humidity control that responds to varying equipment heat loads
  • Local climate control – airflow is provided to one or more cabinets in a closed system, or cooling to the entire space in an open airflow configuration
  • Simple maintenance – tool-less fan replacement, easy-to-access electrical connections and remote notification of all operational parameters
  • Redundancy – up to 8 units can be interconnected, with coordinated air flow, alarms, and time-of-day operation
  • Reduce the need for a dedicated room to support IT equipment.  With proper planning and physical security, it is possible to place these systems out on the floor or shared space. The costs to build and maintain a dedicated IT room are eliminated

LEARN MORE ABOUT OUR 20kW LCP RACK AND INLINE DX

Today, every organization, no matter the size or industry, relies on optimum IT equipment performance in order to meet its ongoing operational demands. If yours is putting rack cooling needs at the mercy of your building’s HVAC system, the risk of system downtime is very real, and the potential cost to operations significant. The best protection against system failure is to utilize IT cabinets with liquid cooling capabilities that offer precise control of temperature, humidity and airflow – all critical factors when it comes to ensuring that your organization’s work is never disrupted.

CMA/Flodyne/Hydradyne is an authorized  Rittal distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

New hydraulic design for presses

Guest contributor: Stefan Zimmerman

New drive concept makes hydraulics economical and intelligent

By means of variable-speed pump drives, new, patented hydraulic axes simplify the design and control of presses of any kind. They considerably reduce the power consumption as well as the required oil quantity by up to 90 percent. To this extent, the control technology of a valve control moved into the software of intelligent servo drives of a displacer control. This reduces the complexity and opens up new levels of flexibility and of condition monitoring.

Worldwide, the climate change has increasingly drastic effects on the everyday life. Thus, governments and international organizations have defined climate targets in order to limit the CO2emissions. What has already become standard in light bulbs and household devices also takes increasingly more effect in the industry. Energy-efficiency has become a decisive criterion for the machine users when it comes to the selection of machinery and systems. They expect a considerably increased output with clearly reduced current and resource consumption. Apart from that, numerous companies have already publicly obliged themselves to reduce their CO2 emissions by defined quantities. They can only achieve these targets if new machinery and systems are considerably more energy-efficient. So it is the challenge of machine manufacturers to develop new concepts.

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Using the hydraulic force density as required

In large systems with very high processing forces as they are required for forming methods, the hydraulics as main drive is one of the largest power consumers. The end users have accepted this for a long time as they wanted to have the maximum force available at any time, even if the process did not permanently require it. Modern hydraulic drives distinguish themselves by the physical unique selling points such as power density and robustness; however, they clearly reduce the power consumption by controlling the displacer as required. Thanks to its hybrid concept, the new hydraulicAxis patented by Bosch Rexroth for presses of different kinds, from low to high drive power, connects the advantages of hydraulics with those of the electric drive technology. First equipment according the new concept has shown that the power consumption can be reduced by more than 30 percent. The required oil quantity of the hydraulic installation can be reduced by up to 90 percent.

Conventional hydraulic systems

For decades, conventional systems have proven of value for presses in the medium and high performance range as drive technology of choice. In this connection, these systems mostly work with a central hydraulic power unit with several variable displacement pumps.  Moreover they are operated by electric motors directly connected to the mains. Apart from that, central or decentralized manifolds with on/off and proportional servo valve technology are required in order to control the cylinder(s) in rapid traverse, working or pressing mode and in the so-called return.

One disadvantage of this concept are idling losses during the standstill times. In the control of the cylinders, there are also throttle losses caused by the valve control. There is partly considerable heat introduction into the hydraulic oil, which must afterwards be compensated again by corresponding cooling.

Hydraulic axis replaces central power unit

A new, patented hydraulic concept replaces the previously common central power unit with valve control by a patented hydraulic axis with speed-controlled displacer control and a closed, decentralized fluid circuit. The hydraulic axis consists of a differential cylinder with a cylinder chamber and ring chamber. The cylinder chamber is for a powerful working movement and the ring chamber for the fast rapid traverse movement. An auxiliary cylinder takes up the oscillating volume during the different movements and in this way creates a closed circuit. A central oil tank is no longer necessary and thus completely omitted.

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The flow is generated by variable-speed pump drives. In order to satisfy the high precision and dynamics requirements, servomotors in combination with adjustable axial piston pumps lend themselves. Thus, all options of the 4-quadrant operation are available to the design engineers. With several cylinders, a corresponding number of Hydraulic axes is used. The synchronization control is performed by the software of the intelligent servo drives, synchronized by means of real-time communication.

Reversal of the movement by changing the direction of rotation

The area switchover for the relevant movement is effected by means of two valves. During the pressing process, the cylinder areas are large. Thus, the cylinders reach high forces at low velocity. During the return of the cylinders, however, the areas in the ring chamber are small in order to achieve the maximum rapid traverse velocity with low forces and to thus reduce the downtimes of the presses. For the reversal of the movement, the servomotors change their direction of rotation. If adjustable axial piston pumps are used, the swash plate of which can be swiveled through zero, the direction of the movement can also be changed by adjusting the swivel angle.

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Energy efficiency in practice: Presses consume more than 30 percent less

The hydraulic axis works in a strictly need-oriented manner. At partial load, the servo drive controllers reduce the speeds of the pump motors to the lowest value possible. During standstill times, e.g. for cooling down the tools, the motors are standing and do not consume any energy. During that time, safety valves support the return. Depending on the cycle times, variable-speed pump drives allow for energy savings of more than 80 percent as compared to constantly driven power units without variable displacement pumps. In practice, the first presses with hydraulic axes achieved reduced consumption of 30 percent as compared to already energetically optimized, conventional hydraulic solutions.

BR_Homburg_Booster-105Regarding the Sytronix family, Rexroth offers more than one hundred pump drives with variable speed relating to power and function. These can be integrated into all usual automation structures thanks to multi-Ethernet interfaces.

Exceeding the savings due to the need-based closed-loop speed control, additional functions increase the energy efficiency of the presses even further. In the lowering movement, the servomotors recuperate the braking energy and either feed it into an electric accumulator, make it available to other actuators, e.g. handling axes, via an intermediate circuit or feed it back into the mains.

Synchronization control of the hydraulic cylinders via intelligent software

The synchronization control can be effected via all common real-time protocols such as PROFINET, Ethernet IP, EtherCat or Sercos if the servo drive controllers provide corresponding multi-Ethernet interfaces. Changes in motion sequences are only transmitted via the machine control by means of software command to the intelligent drives. Mechanical adjustment works at the hydraulic axis are not necessary. So due to short changeover times, end users gain flexibility. At the same time, you can continuously document the manufacturing processes of every component by means of the servo-drive data. This satisfies the increasing demands on the traceability of products.

90 percent less hydraulic oil – central tank omitted

Due to the new concept of the hydraulic axis, the movements are primarily controlled via variable-speed pumps rather than the throttling of the flow by the valves. So considerably less heat is introduced into the hydraulic oil and only minor agitation results. Result: In the first presses with hydraulic axes, the manufacturer could reduce the oil volume from e.g. 10,000 liters to only 900 liters. This saves space for the tank and reduces the operating costs as in an oil exchange, less than ten percent of the previously used oil quantity have to be purchased and disposed of.

An additional advantage is the clearly reduced average noise emission. With variable-speed pump drives, it is up to 20 db(A) below that of constantly driven pumps. During standstill, the noise level of the hydraulics falls to zero. Due to the omitted tank and complex piping for a power distribution, resonance bodies for the structure-borne sound are omitted. With the new concept, the expenses for the noise insulation are considerably lower.

Easier hydraulic construction with quick commissioning

For manufacturers of hydraulic presses, the conversion to hydraulic axes brings about considerable savings in the design, assembly and commissioning. Tank, cooling and piping are completely or largely omitted as is the valve technology. The variance of different motion sequences is moved from the valve technology into the drive controller software. Here, Bosch Rexroth has, for example, integrated best-in-class controllers for different force/path and synchronization controls. Due to the corresponding commissioning software, the engineers don’t even need in-depth hydraulic knowledge for the initial commissioning. Software wizards propose suitable parameters. This considerably shortens the commissioning phases of a hydraulic press.

Condition monitoring increases the availability

The data that is gathered by the intelligent servo drives anyway and that can be amended by more sensors is particularly interesting for end users. It forms the basis for condition monitoring strategies increasing the availability. Based on the analysis of the data, the corresponding software identifies wear and errors before they will lead to standstills. So machine downtimes are replaced by scheduled maintenance measures.

Find out more about self-contained hydraulic actuators here.

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized Bosch Rexroth distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

Battery production: Increased capacity through intelligent automation
Guest contributor: Hans Niessen, Business Development Manager Industry Sector Semicon, Electronic Manufacturing and Flat Panel Display at Bosch Rexroth 

Manufacturers of modern energy storage systems are faced with the challenge of developing high-quality batteries offering better performance and marketing them in large numbers in the short term. How can automation help when it comes to producing various models and batch sizes not only quickly and flexibly but also in an economical and environmentally friendly manner?

Electric cars, digital mobile devices, decentralized energy storage systems for wind or solar power: in the coming decade, demand for battery cells will increase dramatically. According to the Fraunhofer ISI’s recently published “Energy storage roadmap”, cell production capacities at European plants will have to increase to several hundred GWh by 2030 in order to meet demand in Europe. Manufacturers are in a race against time and must find ways of getting newly developed battery solutions onto the market in large quantities much more quickly.

Mass production with a high level of flexibility

Because the development of more powerful energy storage systems follows short evolution cycles, it must also be possible to adapt production processes quickly. Process and product improvements identified in the laboratory should be adopted in production immediately. How do the various automation partners cope with these requirements? How do they intend to reduce operating costs while ensuring optimum material and product quality and at the same time taking into account important sector issues such as energy efficiency and the use of resources? To achieve these aims in a convincing manner, they must look at all sub-processes involved in battery production – something that requires a broad knowledge of automation given their specific requirements.

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Layout of a battery production facility. Each individual step requires a great deal of highly efficient, flexible automation technology.

High-speed coating of electrodes…

Rechargeable battery cells are manufactured in a variety of forms. Regardless of whether they are cylindrical, prismatic or in the form of a pouch cell, each new generation has specific production and automation requirements. In an effort to achieve greater capacity in an even smaller space, the electrode foils wrapped or folded inside them are becoming increasingly thin and their coating increasingly thick. Highly precise web handling is needed in order to achieve the process speed needed for mass production but without impairing quality. This in turn requires specific functions such as those provided by the Motion Logic Control (MLC) control software from Bosch Rexroth with its libraries. The system is based on the embedded control system XM and allows motion tasks with over 200 distributed axes with sub-micrometer accuracy. Easily parameterizable control algorithms such as speed, force and travel control together with synchronization allow quick engineering with minimal programming work.

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Coating places huge demands on the production system as it has a significant influence over the properties, operating life and energy density of a battery.

… and structuring

As part of the high-precision roll-to-roll process, the two electrodes along with two separators are combined to produce a sandwich structure and, in the case of cylindrical batteries, are formed into a roll. For prismatic cells, they must be accurately stamped or cut using a laser and then stacked flat or folded in the form of a Z. In order to manufacture pouch cells, the electrode sections must be accurately cut, stacked and then welded. Because the stacking and welding are relatively time-consuming processes, they often lead to inconvenient delays in the overall process.

Production steps for various cell types requiring highly efficient roll-to-roll processes and flexible transport systems to prevent bottlenecks.

Flexible transport prevents bottlenecks

In order to prevent bottlenecks when manufacturing batteries, displays and other electronic products, Bosch Rexroth has developed the Flexible Transport System FTS. It is dimensioned according to the mass to be transported and transports the individual workpiece carriers independently of one another from station to station. As a result, maximum acceleration is possible at all times. The multi-product system can take on exact positioning tasks at the same time. Thanks to a more flexible layout, more time-consuming processes can be carried out in parallel, thus doubling productivity. With these new possibilities, the production of notebook and smartphone batteries could be increased by almost 200 percent without impairing the time to market.

With the Flexible Transport System (FTS), Bosch Rexroth prevents typical bottlenecks in battery, display and electronic production.

Producing battery packs quickly and stably

Before it is closed and sealed, the battery needs to be filled with electrolyte. It should be as full as possible so that only minimal spaces remain in the separator foam. Because the liquid is toxic, the process must be completed quickly in order to avoid contaminating the environment. The individual battery cells are then combined to form modules. Automated systems are also used to produce the housings for the battery packs in large numbers and with minimal waste. Solutions such as the IoT Gateway from Bosch Rexroth which collect sensor and control data and passes them on to cloud platforms or on-premises solutions for analysis and evaluation are ideal for monitoring process stability and making continual improvements.

Highly efficient, flexible module production

A typical battery pack is made up of several cells and a management/cooling system. In order for manufacturers to adapt their existing production lines quickly in the event of product changes or to react to changing batch sizes, they should standardize automation and handling and at the same time ensure adequate flexibility. Once again, the flexible FTS transport system is an option here. Thanks to its scalability for products weighing anything from 1 g to 2,000 kg, it is suitable even for large vehicle batteries.

Green processes: efficient energy use

As an automation provider with expertise in a range of technologies and the ability to collect and analyze data from machines and systems quickly and easily, Bosch Rexroth helps machine manufacturers when it comes to green processes too. When used in battery production, the Rexroth 4EE (Rexroth for Energy Efficiency) system helps to increase productivity while conserving resources, cutting emissions and reducing operating costs. This is possible thanks to four levers which work throughout the life cycle:

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Rexroth 4EE: The holistic view of machines and systems over their entire life cycle allows energy consumption, emissions and operating costs to be reduced sustainably while increasing productivity.

Productivity requirements demand full expertise

In spite of the various challenges in battery production, the situation from the point of view of an experienced automation partner is not new. The experts from Bosch Rexroth have already helped companies in the solar, photovoltaic and semiconductor industries to cope with the changes in their sectors and can therefore offer users and machine manufacturers competent advice. Over 20 years’ expertise from the printing industry has gone into the company’s roll-to-roll solutions. Open Core Engineering which allows the simulation and virtual commissioning of new automation solutions also plays a key role in reducing the time to market. Bosch Rexroth relies on open standards such as OPC UA in order to continually improve processes and provide condition-based maintenance. With innovative system solutions such as the FTS, global service and an international network of machine manufacturers, the basis for quick and lasting success in the market is already in place.

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized Bosch Rexroth distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

New Design for Hydraulic Power Units

Guest contributor:  Andreas Günder, Bosch Rexoth

Optimum power, less installation space: Thanks to new intellectual and design approaches, compact hydraulic power units increase the economic efficiency of machine tools.

Powerful force in a very confined space

In the production world, hydraulics are firmly established. Machine tool manufacturers appreciate hydraulics for their high power density, toughness and modular design. In the lower performance range up to 4 kW, however, there are also some challenges. Since the installation space is often limited, designers and technical purchasers are constantly looking for increasingly compact solutions.

Installation space is valuable

The demand for compact hydraulic drives is not only due to the structurally limited flexibility regarding extensions, modernization measures and refittings but also due to the requirements regarding acquisition costs and assembly times or structural extensions of the working space with given machine dimensions. In addition to the level of integration of the functions, energy efficiency often plays an important role as well. Last but not least, many manufacturers are following the miniaturization trend. If workpieces become increasingly smaller, the moved mass of the machine tool has to be decreased accordingly.

“Installation space eaters” hydraulic power units

To reduce the installation space, solution manufacturers can start mainly with the following components: hydraulic power unit and control cabinet. When considering this split, it becomes evident that compact power units which are also easy to integrate require completely new design approaches to eliminate all features which waste unnecessary space in the performance spectrum up to 4 kW and to ensure that the units are still compatible with many different machine designs.

Highly integrated design approaches

The features of such innovative design concepts according to the EU Eco-Design Directive 2009/125/EC for example include a tank which is optimized for efficient degassing and reduces the oil volume by up to 80 percent. A much more decisive factor for gaining space is, however, that all functions can actually be integrated in one small power unit – from an economic variable-speed drive for demand-based power output to sensor technology with filling level, temperature, pressure and filter contamination sensors to a completely wired frequency converter.

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Compact and ready for Industry 4.0

For the future viability of this approach with regard to Industry 4.0, a data interface is essential as well. Only with permanent condition monitoring can the operating conditions be optimized comfortably and relevant faults be detected early on. With this equipment, the user only has to connect the electric power, the data interface and the hydraulic supply during installation and the hydraulic power unit is ready for operation

New cooling with heatpipe

So-called “heatpipes” are considered to be a space-saving innovation regarding the cooling of hydraulic power units. Their high-performance passive thermal conduction allows for a further reduction of the frame size. The heatpipes absorb the thermal energy of frequency converter, motor and hydraulic oil and efficiently transfer it to a central heat sink such as e. g. cooling water…
This ensures an intelligently optimized thermal management within the hydraulic power unit and optimally utilizes the cooling power of the cooling water. There is no need for a separate hydraulic circuit for oil cooling. This reduces installation space, noise emissions, energy consumption and possibilities for leakage.

Heatpipe – Functional principle

Basically, a heatpipe consists of air-tightly sealed copper pipes with underpressure. Inside, there is a medium which transfers thermal energy. In the temperature range of hydraulic power units, the medium may be e.g. distilled water. The boiling temperature of the water is significantly reduced by the low pressure within the heatpipe, which means that a boiling or condensation process can already take place at low temperatures.

Functionality: If you dip the heatpipe for example in hot hydraulic oil, the thermal energy at the lower immersed part of the heatpipe is transferred to the water. The water exceeds the boiling point, evaporates and absorbs a large amount of thermal energy with low temperature difference (latent heat). The water steam rises to the upper part of the heat pipe which is cooled by e. g. a cooling element. Here, the water steam condensates and gives off the thermal energy to the cooling water. Thanks to the latent heatabsorption and dissipation, the thermal conductivity of heatpipes can be up to 1000 times higher than the thermal conductivity of copper pipes. Due to the high elasticity of the copper pipes, the heat pipe can be easily shaped. In this way, ideal heat paths can be formed inside the hydraulic power unit and the installation space can be considerably optimized. Similar application ranges with equal optimization potential can be found in computer technology. Here, the thermal energy in laptops caused by heat sources such as the CPU are transferred to the central cooling elements using heatpipes.

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Plug & Play: no control cabinet

The frequency converter has a high potential for gaining installation space as well. If it has already been equipped with Multi-Ethernet interface for Sercos, Profinet and other standards by the manufacturer, machine and plant manufacturers are able to reduce the control cabinet requirement for the hydraulic unit by up to 100 percent. As a precondition, however, the sensor technology and the motor in the power unit have to be wired to the frequency converter in such a way that the frequency converter can control the hydraulic pressure autonomously. This means that the control cabinet can not only be designed with smaller dimensions. Sometimes it can even be completely omitted together with the corresponding installation effort and related sources of error.

Conclusion

Fully integrated small power units based on a completely innovative design approach for the performance range up to 4 kW provide machine and plant manufacturers with the advantages of hydraulic drives with very little space requirements. As an alternative to purely electrical solutions, the required energy can be converted into a linear movement in a precise and costeffective manner directly at the working area using a simple hydraulic cylinder. If sensor technology, frequency converter and data interface are integrated as well, users not only benefit from comprehensive condition monitoring but also from a significantly reduced control cabinet footprint or even from a design without control cabinet.
More information fully integrated power units: www.boschrexroth.com/cytropac

Operating principle: https://www.youtube.com/watch?v=sSPemS94G2I

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CMA/Flodyne/Hydradyne is an authorized Bosch Rexroth distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

Best Practices: Inconsequential Volume

Guest Contributor: SMC

The advent of manifold mounted, plug-in pneumatic valves has been a boon for machine builders. It allows them to mount complete valve packages in a safe and secure location on a machine. Using a D-sub connector, serial interface module, or similar single-point wiring system, all of the electrical control outputs can feed into one location on the manifold, greatly simplifying the wiring. Plumbing issues are reduced, since a single air pressure line can be used to feed a common pressure gallery. The same advantage applies to the common exhaust gallery. No longer would both a plumber and an electrician be required to replace a valve, since any valve can be replaced without disturbing electrical connections or plumbing lines.ex260_ported

Like most advances, there can be some downsides to this type of arrangement, depending upon the application. One of these revolves around considerations for energy conservation. Most circuits include two air lines extending from the valve to the actuator, one for extend and one for retract. Each time the valve cycles, the actuator is pressurized on one side or the other. Of course, the hose or tube that connects them must also be pressurized. This tubing volume is typically ignored as inconsequential when doing our sizing calculations, but should not always be overlooked.

The tubing volume offers no work at all…only a means of transferring the energy of the compressed air to the actuator. Inconsequential? Maybe. But depending upon the application, those volumes can be significant. Here is an example:

A packaging facility has corrugated boxes being erected at a mezzanine level and dropped down to the main floor where they are filled, sealed and palletized. The box drop-down employs gravity to lower the boxes, but incorporates a series of mechanical stops to sequence them as required. Each of the stops includes a pair of 2 inch bore x 1 inch stroke air cylinders to operate a brake that stops the box and releases it when needed. In all, four stops are included for each drop down, meaning eight actuators in total and four valves to control them.

The directional control valves are located at a central location on a single manifold, presenting a clean and compact package. However, the distance from manifold to actuator varies from 10  feet to 25 feet. In operation, each time a valve shifts, it exhausts one length of tubing and fills another. Given the small volume, we might still think this to be inconsequential, but let’s look at the numbers.

Assume ¼” OD tubing with an ID of approximately .180“. With the first station being 10 feet away from the valve, the volume of tubing going to the actuators is only 3.05 cubic inches. Since there are two lines from the valve to each actuator pair, the total volume is 6.10 cubic inches per complete cycle. To put this in perspective, each of the 2×1” cylinders has a total volume of 5-½ cubic inches. That’s the sum of both the extend and retract sides. Since there are two of them, the total cylinder volume is 11 cubic inches. The volume in the tubing is over half that of the actuators. Much of the energy developed at the compressor is being used to fill the tubing lines.

Let’s leave aside the potential problem with poor response times, and just look at the costs. Let’s also assume the working pressure to be 80 psi. By calculating the compression ratio to be 6.33, and multiplying that by the volume, the normalized volume becomes 38.6 standard cubic inches. If we have the cylinders being actuated five times a minute, we will be consuming 193 standard cubic inches per minute, or using more meaningful terms, 0.11 SCFM. That is just for filling the air tubing to the closest single station on the drop-down. How about the other 3 stops on the drop-down?

The chart below shows the air volume for each of the stations, with a total for all. Please note the total volume of the airlines extending out to the cylinders is 42.8 in³. When we calculate the total volume of all eight cylinders we get 44 in³. The volumes are almost identical. Now we have a situation where half the compressed air is consumed filling all the air lines.

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If that single drop down operates 24/7 and the cost for electricity is $.10 per KWh, the annual cost to fill those lines is about $110, the same costs we incur to fill the cylinders. With multiple drop-downs, the costs are multiplied. Staying with our example, the facility has 50 packaging lines, for an annual cost of $5500.

While this may be viewed as an extreme example, think back on all the applications where long air feed lines were employed in order to have a clean valve package. Or consider the oversize tubing that was utilized just because it was handy. Many of us might figure that larger tubing is better anyway, and everything will run more efficiently. However, please take into account that the larger tubing may double the volume to be filled without adding any productive benefit at all.

What happens to the same example when 3/8 inch tubing is used instead of the ¼ inch? The tubing ID increases to .27 inches and the volumes increase by a factor of 2.28, as do the costs. Now the annual price tag has jumped to $250. Again…that is just to fill the tubing for one drop-down.

As a side note, there is also some potential for liquid moisture build-up in those long lines when an excess of air is left between the valve and the actuator, even when good air filtration and drying is in place. Problems can arise due to the adiabatic expansion that occurs with each exhaust cycle. Condensation may occur as the exhausting air temperature falls below that of the atmospheric dew point. With long air lines and many cycles, the moisture may not be completely exhausted and can accumulate in the lines. That accumulation will occur near the actuator ports and will eventually work its way into the actuator, shortening its life.

What’s the solution? Have the valves mounted on or near the actuators so that all or most of the air volume is used to actuate the cylinders. This will require a pressure line running the length of the drop-down with a connection to each valve. However, that pressure line represents energy capacitance that works in our favor. We will also have fewer connections, which will translate into fewer potential leaks. Of course, the downside is that electrical lines will have to be extended independently to each valve. However, with low voltage, low wattage coils, this probably is not that difficult. Another benefit to be gained is that electrical response times remain unaffected, while pneumatic response times improve dramatically.  The dollar savings is the reduction in air consumption by half. In our plant, that could be up to $5500.00 every year.

Reducing the costs for compressed air needs to be an ongoing project for any company that uses substantial amounts of air as part of the manufacturing process. There is a tendency to approach the issue at the compressor room and look for answers there. The resulting recommendations can be expensive as well as require a long ROI. However, dealing with demand side issues, as described here, offers an easy solution that can be incorporated at the OEM level with little additional cost. A case can even be made for modifying these types of applications in the field when machines come due for refurbishment. Addressing these “inconsequential” issues will offer significant savings on the bottom line. “Watch the pennies and the dollars take care of themselves”.

To learn more about Best Practices in Pneumatics, please visit http://www.smcusa.com/

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CMA/Flodyne/Hydradyne is an authorized  SMC distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.