Keg filling is a critical process in breweries large and small. A machine that helps speed the process – aided by pneumatics – has recently been introduced by KHS, an OEM based in Dortmund, Germany. Its Innokeg Till CombiKeg is a compact keg washer and racker well suited for craft brewers. It leak tests, washes, and fills up to 90 kegs per hour, and can handle both disposable and reusable kegs in sizes ranging from 10 to 58 liters – giving brewers the flexibility to switch configurations as market demands change.
In designing the machine, KHS engineers needed to ensure efficient, precise, and consistent contact pressure on the treatment head (the interface between machine and keg) during all phases of the process. They also had to pay special attention to hygiene, a key prerequisite for beverage applications. For instance, production areas and surfaces are subject to a rigid and carefully managed cleaning regime. And, to meet the demands of a range of different customers, the unit must handle processes from semi-automatic individual cleaning and filling to fully automatic keg paths.
They solved this problem by installing an IVAC cleanline pneumatic cylinder from Norgren to control the head. The space-saving IVAC comes as a complete, ready-to-connect unit with built-in main and pilot valves, magnetic switches, speed controls, and a central connection for compressed air, electrical power, and data.
The IVAC markedly differs from traditional pneumatic technology. Generally, pneumatic control on machinery involves a combination of valves or valve islands, actuators, flow controls and sensors, along with various connectors and accessories needed to make them all work together. According to Norgren, typical applications require up to 13 different components for each actuator function.
Putting together a system from this many components builds in some inherent disadvantages and performance limitations. First, multiple components must be specified, acquired, installed, and maintained. All of this consumes time, space, and money. These components must be connected with numerous tubes and wires, which complicates installation and maintenance and multiplies the number of potential failure points. It also makes cleaning more difficult. Finally, the size and complexity of the arrangement slows response times and wastes compressed air.
To overcome these limitations, Norgren developed a modular motion-control unit that combines all these components in a single Integrated Valve and Actuator Control (IVAC) element.
The IVAC starts with a double-acting cylinder in bores ranging from 32 to 100 mm. Integrated 5/2 or 5/3 valves are sized to match the cylinder. A module seated on top of the IVAC contains small, electrically operated pilot valves that shift the main control valve and drive the cylinder. Combining the pilot valve module and cylinder reduces tubing and space requirements. A single IVAC can also control an additional external cylinder.
The directional valve also features a glandless spool. With the inner and outer parts of the Teflon-coated spool precisely matched, no rubber seals are required. This gives the valve exceptionally long life, usually in excess of 200 million cycles – three to four times that of a typical valve with a seal, according to Norgren. However, if maintenance is needed, say to change the valve function, the IVAC’s modular design makes it simple to remove the spool and install a new one.
Flow controls in the cylinder end caps contribute to a streamlined design. The controls are tamper resistant, so they are less prone to random operator error. They improve speed control by greatly reducing any air-spring effect, especially when compared to sandwich flow controls on valve islands. The integrated design eliminates the inefficiency inherent in controlling flow from a location removed from the actuator.
For similar reasons, the time it takes to initiate a move once an electrical signal is sent is much shorter for the IVAC than for a conventional cylinder. Because the valve and cylinder are integrated in a single package, no time is required for air to fill the tubing between the valve and actuator.
Combining all these functions in one efficient design results in an integrated unit with just one electrical connection, one compressed-air connection, and one exhaust port – all at one end of the IVAC. And, it fits in the same dimensions as a standard ISO 15552 or VDMA footprint cylinder.
For KHS, the IVAC offers some key benefits in addition to fast and efficient motion control. The cylinder specifically meets the hygiene standards required in food and beverage operations. The IVAC cleanline model uses standard food-grade lubricant, and all adjusting screws are covered. Magnetic switches that verify actuator movement are integrated inside the IVAC casing. This keeps the profile smooth for easy cleaning and prevents tampering. The switches are accessible under a screw head, should adjustments be required.
The cleanline IVAC is rated IP67, meaning it can withstand not only water spray, but also temporary immersion up to one meter deep. This is important where the IVAC is exposed not only to water for washdown but other liquids containing organic matter or sticky substances.
The IVAC module also greatly simplifies installation, reducing labor time and cost. It eliminates the need for mounting valve islands to the machine framework or inside a cabinet. There is no pipework to run around the machine connecting each valve to each actuator. This contributes to a clean, uncluttered appearance – an increasingly important factor for today’s OEM.
Finally, another benefit is energy savings. Because the IVAC eliminates piping and connections previously used to link the cylinder and valve, the unit can significantly cut energy use. It is estimated that replacing traditional pipework and connections with IVAC technology can reduce energy consumption by up to 50%, depending on the application.