Growing consumption of bottled drinks increases the pressure on manufacturers to produce more and they in turn push production machines upon which they rely to the limit. Manufacturers often demand 24 hour production, leaving little or no time for maintenance, and resulting in premature machine failures which dramatically impact availability. The goal of overall equipment effectiveness (OEE), at 80% or higher, often clashes with a reality of around 60%.
One of the most critical applications determining overall OEE in beverage manufacture is the filling machine itself. Applications include the filling of glass bottles, cans, pouches, tubes, and PET with contents ranging from water and tea to smoothies and yoghurt. Therefore the filling equipment must be accurate, versatile, hygienic and reliable. This is demanded by manufacturers even when these machines are operating continuously, at high speeds, and without planned maintenance breaks.
This article explores a new approach and considers the potential of automated lubrication systems and food-grade lubricants in beverage filling machines. Efficient lubrication of moving parts is essential for optimal beverage production. SKF customers in the beverage industry often list the following aspects of lubrications critical to the performance of filling machines.
• Too little grease: Lack of lubricant shortens the lifetime of the bearing and the machine. Both under- and over-lubrication can be due to imprecise metering, but also because some lubricating points are simply forgotten, especially those that are difficult to reach or cannot be accessed while the machine is in motion.
• Too much grease: The paramount risk here is costly contamination of the product. But even more critical is that grease can enter the water used to clean the machine, requiring water treatment processes to meet environmental regulations.
• Complexity: A filling machine may have up to 80 lubrication points, many of which are located inside rotating mechanical parts and therefore impossible to access while machinery is running. Manual access might be complicated by safety concerns. Components vary and their efficient lubrication can be complex.
• Corrosion: Lubrication systems may not be designed to operate under the aggressive conditions of the beverage industry, such as high humidity, leading to corroded metering devices, grease nipples, and piping. Mandatory frequent high-pressure washing of bottling lines poses a real challenge to the integrity of bottling mechanisms and their lubrication.
Centralised, automatic lubrication systems (ALS) have the potential to increase machine availability, while reducing reliance on scarce talent. These systems provide the appropriate quantity of lubrication at the correct intervals to the correct lubrication points, minimising friction and wear and optimising bearing and machinery service life. ALSs are designed to lubricate individual machines or entire plants. Moreover, automation removes human error, hugely simplifies lubrication management, reduces lubricant consumption, and thereby enhances the overall efficiency of the bottling process.
The main factors that determine the correct solution are:
• Dimensions: The size of the filling machine determines the number of lubrication points, and thus total lubricant consumption.
• Variation: The chosen system must have the capacity to deliver an exact quantity of grease or oil to each lubrication point, which may vary according to the part of the machine to be lubricated.
• Technical parameters: The system must consider back pressures at the lubrication points, operating temperature range, the choice of lubricant itself, the feed pump’s drive energy, control and monitoring.
• Type of mechanisms to be lubricated: Bearings, gears, selection screws, etc.
• Factory environment: In most circumstances, stainless steel components are essential to avoid corrosion. However, not all automated lubrication systems use corrosion-free materials.
Types of automated lubrication systems include single-line and progressive automatic lubrication systems. Single-line lubrication systems can be used to service one machine, different zones on one machine, or several separate machines. A pump delivers lubricant to an adjustable metering device that services the lubrication points, delivering a precise amount of grease or oil. Sensors monitor system pressures, and send signals to the control unit at preadjusted critical values. The control unit enables lubrication to be triggered automatically at predetermined intervals. Single-line lubrication systems can serve up to 900 lubrication points in machines over distances of up to 100 metres. Smaller systems are fed by compact pump units, including lubricant reservoirs, while bigger systems are fed by barrel pumps.
Progressive automatic lubrication systems are the most common lubrication solution in the food and beverage industry. They can be used on small to medium sized machines with dispersed lubrication points that require varying quantities of grease or oil. Progressive lubrication systems consist of a pump connected to a primary metering device, outlets from which they are connected via pipes or high-pressure hoses to the lubrication points of the filling machine.
The pump supplies lubricant to the meter, which splits the lubricant into predefined amounts, which in turn are pumped to the lubrication points, or alternatively to the inlet of a secondary metering device, thereby enabling more points to be lubricated. Progressive lubrication systems can dispense a precise, metered amount of lubricant to up to 150 lubrication points over distances of approximately 15 metres.
Some 99,5% of operated beverage filling machines are manually lubricated. Although there is an initial cost to installing an ALS, the return on investment can come faster than might be assumed. In addition to a significant reduction in labour costs, there are also considerable savings from reduced downtime and extended component life. There is no need to stop the machine for lubrication, only to keep the system filled and maintained, so efficiency is enhanced. Lubrication that takes place while the bearings are rotating also improves the distribution of lubricant. A small amount of grease remains flowing, keeping out contamination even when the machine is operating in a harsh environment.
Smart sensors and digital measuring devices also make it possible to monitor the entire lubrication process constantly. Monitoring and control are essential to the efficient operation of lubrication systems. Installed in conjunction with intelligent monitoring devices, automatic lubrication systems can facilitate economical and optimal lubrication. The resulting data can give operators advanced warning of lubrication or machine failure, enabling preventive action to be taken.
Economic advantages of automatic lubrication systems for filling machines include:
• Increased asset availability: With the reliability that comes with automated lubrication, the frequency and duration of downtime, because of mechanical failures, is sharply reduced. SKF has experience of applications in which downtime reduction has been up to 80%.
• Lower consumption of spare parts: With lubrication failures eliminated, annual consumption of spare parts such as bearings, chains and gear wheels is reduced on average by around 50%, according to SKF’s experience.
• Reduced maintenance costs: accurate and appropriate lubrication removes one of the main causes of machine failure.
• Higher speed: A bottling plant can as much as double the speed of a spiral conveyor, because automatically lubricated transmission chains can run faster without damaging the bottles.
Higher productivity, improved worker health and safety, and reduced risk of product contamination are additional benefits offered by ALS. All the above factors combine to deliver a swift return on investment in automated lubrication systems for beverage filling machines, offering rapid return on investment.
Regulation is increasingly affecting global food and beverage production, with stricter rules for food processors to change their processes or modify their machines. Upgrading to automated lubrication can bring the additional benefit of compliance with existing or anticipated regulations.
SKF and Lincoln lubrication products, systems, and services are available through a global network of distributors, supported by a unified sales organisation around the world to offer turnkey solutions and extensive aftermarket support, including food-grade lubricants tailored to the beverage sector. SKF is committed to your success through optimising your lubrication management.
| Tel: | +27 11 821 3500 |
| Email: | samantha.joubert@skf.com |
| www: | www.skf.co.za |
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