Energy-efficient cleaning

In the wake of rising electricity, oil and gas prices, energy efficiency in component cleaning has become increasingly important. Opportunities to reduce energy consumption can be implemented in existing cleaning systems as well as in new ones to be procured.

Reducing energy consumption and the associated_{carbon footprint} has been an issue for some time. Not least because when banks evaluate companies, the aspect of how well they are positioned to achieve climate protection targets is playing an increasingly important role. However, due to the enormous rise in energy prices in recent months and the uncertain supply situation for fossil fuels, saving energy has become an economic necessity. Companies are therefore looking for potential savings in all areas, and component cleaning as a quality-assuring manufacturing step is no exception.

Do not look at parts cleaning in isolation

The most energy-saving and cost-effective cleaning is that which does not have to take place. Conversely, this means that the less cleaning is required to achieve the specified technical cleanliness, the lower the energy demand and costs. In addition to the choice of the right cleaning method and process, the amount of contamination introduced therefore influences the energy and time required. Here, potential savings can often be exploited cost-effectively without making any technical changes to the plant.

This includes checking part-specific process parameters once they have been defined. They are usually defined on the basis of a worst-case component, resulting in treatment times of ten to 15 minutes or even longer for cleaning, rinsing and drying. However, since the vast majority of workpieces to be cleaned are much less contaminated, energy and time are wasted - these parts are cleaned longer than necessary. If it is possible to avoid worst-case parts and to enter the system with workpieces that are as little contaminated as possible, treatment times can be significantly shortened and energy consumption reduced accordingly. This directs attention to the optimization of the pre-processes, whereby each production step must be examined from the point of view of technical cleanliness. The aim is to minimize net contamination before cleaning and keep it constant. One measure here can be, for example, a simple intermediate cleaning step in production by blowing off or counter-rinsing with clean machining medium that is available anyway. In addition to improved energy efficiency, this procedure makes it possible to maintain and secure a certain quality level. At the same time, the reduced dirt load reduces the energy required for media preparation.

Plant optimization options

On the plant and process engineering side, a wide variety of measures help to reduce energy consumption. To prevent or minimize heat loss, piping and relevant plant components should be well insulated. Optimized mechanical processes that enable more effective and faster cleaning of particulate and filmic contaminants also offer approaches. For example, kinematic cleaning and drying, in which the basket and nozzle system rotate in the same direction or in opposite directions, can save up to 20 percent energy compared with static nozzle systems - based on the process-specific energy requirement of the machine.

The positioning of the parts in the working chamber also influences energy consumption. They should be easily accessible from all sides for the medium and the process mechanics. This can be achieved by designing the bogie in the working chamber to be as open as possible.

In the case of units such as pumps, frequency control ensures that they are not constantly running at maximum output and thus wasting energy. Speaking of continuous operation, software solutions for efficient energy management, which, for example, shut down the plant to a "real" standby mode during breaks in operation or times when no goods are available, can save a lot of electricity and money. Depending on the design, their use requires effective production planning so that the plant is ready for operation when needed. Especially in new plants, the required pump capacity can be noticeably reduced if the piping is routed with fewer bends, angles and kinks. However, this requires somewhat more installation space.

When it comes to heating the cleaning and rinsing baths, heat recovery solutions, heat pumps and heat exchangers ensure that the energy used is kept in the cycle and does not have to be constantly replenished. Developments such as the Heat X heat exchange module enable heat from external sources, including solar thermal and process heat, to be coupled in. The costs for these solutions are still comparatively high in some cases, but the payback period is shortening noticeably due to the rise in energy prices.

Drying - the most energy-intensive process step

Component drying is the biggest energy consumer, especially when cleaning with water-based media. More effective drying technologies therefore offer comparatively great potential for energy savings. Approaches include the combination of infrared and vacuum drying as well as steam drying. Condensation drying with a heat pump takes place in a temperature range between 20 and 90 °C, depending on the components and application. Savings of 75 percent and more can be achieved with these solutions compared with conventional hot-air drying. They can be implemented as stand-alone drying systems or integrated into the working chamber of the cleaning system.

The right cleaning container reduces energy consumption

The cleaning container plays an important role in terms of both energy and quality. Boxes made of galvanized perforated sheet are counterproductive here. They prevent the process mechanics from reaching the parts without restriction and thus extend the cleaning time. The dripping behavior is also poorer, which makes significantly longer and thus more energy-intensive drying processes necessary. Cleaning baskets made of round wire, which ensure good accessibility on all sides, are optimal.

Dry cleaning - as an alternative to save energy

Based on the components, the required technical cleanliness and the possibilities to reduce the input contamination by optimizing the pre-processes, the question arises in many cases, is wet-chemical cleaning necessary or can the requirements be achieved with alternative, dry cleaning processes, including plasma, laser,_{CO2 snow-jet} or steam cleaning. For applications that require only partial cleaning for, for example, a bonding, sealing, coating or assembly process, these solutions, which can be easily integrated into the production process, offer more than just energy advantages over classic all-over cleaning.

Plant manufacturers provide support in the optimal design of cleaning processes and parameters as well as the optimization of pre-processes, for example through process analyses and other services. The development of innovative solutions for the digitalization of cleaning processes and the use of artificial intelligence for the demand-oriented adaptation of cleaning are further steps taken by manufacturers for energy-efficient and_CO2-reduced operation. Intelligent networking of building, supply and production technology also makes a contribution.

Author: Doris Schulz

Deutsche Messe - parts2clean
www.parts2clean.de