The cavitation phenomenon and patented, hybrid technology for channel cleaning

Cleaning method deployed in CoolingCare devices is based on the patented method of two-way pulsation of the cleaning medium. HYDRAULIC SHOCK WAVES GENERATE A CONTROLLED CAVITATION PHENOMENON THAT INITIATES THE PROCESS OF REMOVING SCALE AND RUST FROM THE CHANNEL SURFACE. Rapid compression and expansion of the liquid in the channel causes local pressure drops, resulting in the formation of thousands of cavitation bubbles. Cavitation cleaning is supported with a water-based cleaning solution, which additionally supports the dissolution of deposits on the channel walls. Unlike other technologies, where the cleaning method is based on pumping aggressive cleaning agents through the mold cooling circuits, the hydromechanical, hybrid cleaning method using the cavitation effect taking place inside the channel quickly and effectively removes limescale deposits mechanically, allowing the use of less aggressive, safer cleaning agents. After cleaning, the channels are automatically rinsed with water and dried with compressed air. The use of the hybrid pump / cavitation generator method allows to obtain high turbulence of the flow of the cleaning liquid and thus reduces the cleaning time. The patented method of cleaning using the ‘water hammer’ phenomenon is the only one on the market that enables unblocking completely clogged channels.

Cavitation effect demonstration video

How do I know if channels are clean? - Intelligent cleaning modes

The cleaning time of the individual cooling channels may and should differ from each other, taking into account the fact that each of the channels often has a different diameter, geometry and length, which affects the generated pressure losses and therefore the cleaning time. Therefore, the method of setting the same cleaning time for all channels, which is often used by manufacturers of devices for cleaning cooling channels, is very imprecise. Assuming all the channels will be equally clean after the same cleaning time is just wishful thinking, which can be far from their actual condition. COOLINGCARE CA2 and CA6 are the only devices that allow users to define a flow rate reference value as a benchmark for future cleaning. In the case of a new tool, a machine operator measures the flow rate values of the individual channels and saves them in a database. When the mold goes back for maintenance, the operator specifies a target percentage of the original flow rate to be achieved. The machine then begins the process and monitors the flow rate. After reaching the desired flow rate, the cleaning process ends, and the operator is informed about in the result with a text message sent to his phone number. In a case of an old tool, a machine operator selects “clean to stable result” option. The machine then measures the flow rate changes of individual channels at regular intervals, creating a curve showing the gradual increase in flow. At some point, the curve starts to level off, which will indicate that the maximum flow rate has been reached. When two successive results are similar, the machine stops the cleaning process and informs the operator with a text message that cleaning is complete. The operator can then save the flow rate as a reference for the future.

Device performance analysis

A separate, dedicated feed pump for every channel ensures greater efficiency and dynamics of cleaning. Many cooling channel cleaning systems on the market are equipped with a single feed pump. Such a solution creates many inconveniences that should be kept in mind when choosing a machine for channel maintenance.

Device efficiency – the more cleaning sections the device has, the more channels we will be able to connect to it at the same time, maintaining an independent and repeatable dynamics of the cleaning process.

Comparison of cleaning capacity of different machines

Cleaning time – Time savings we achieve by connecting several channels to one cleaning circuit is illusionary, because such a connection always generates much higher pressure drops, directly affecting the amount of liquid that we are able to pump in a given unit of time, and which has a direct impact on effectiveness cleaning. This is particularly important for single-pump devices, as cleaning efficiency in this type of design depends precisely on the ability of the system to pump as much liquid as possible. In practice, connection of cooling circuits in series requires a significant extension of the cleaning time, at the same time giving no guarantee that all lines will be cleaned equally. Individual connection of channels gives us much greater possibilities of monitoring and controlling both the dynamics of the process, as well as the assessment of its effectiveness.

Measurement of the flow rate – In the case of a single-section device to which the channels are connected in series, the performed flow measurement will not inform the user about the actual flow improvement for individual circuits, but only about the sum of flow rates, which can be compared ‘before and after’ the process. The user will not be able to tell what increases in flow rate values were achieved and whether all channels were actually cleaned to the same degree.

Leakage detection – The bridging of the system has one more, very significant disadvantage. In the event of a leakage, we are often unable to precisely determine which channel has caused it. When we connect the channels individually, finding the cause of the leak is much easier.

Return on investment

Every year, companies around the world unknowingly lose hundreds of thousands of Euros due to the gradual decline in cooling efficiency in their tools and machines. Lower mold efficiency, longer cycle time due necessity of counteracting dimensional deviations of plastic parts, longer mold downtimes, maintenance and servicing – all these factors increase operating costs and translate into a decrease in company profits. The source of these problems originates not only in the quality of the cooling water, but also in the processing temperatures, which translate into precipitation and gradual deposition of deposits and rust inside cooling channels of molds as well as other heat exchangers.

Annual savings for 1 injection molding machine (with cycle time reduction of 1 sec. for 30 sec. cycle time)

Mold safety

Intelligent leakage protection system – Compressed air-based leakage and pressure tests identify leakage or blockage problems before starting work on diagnostic and cleaning media. This gives users valuable insight into the health of their cooling channels. An advanced liquid level monitoring system allows the detection of even small leaks during the cleaning process, minimizing the risk of spillage of the cleaning agent on the floor. In addition, the device can perform leakage control tests of the system during cleaning and automatically stop the process when a leak is detected.
Less aggressive cleaning agents – High dynamics of the cleaning process combined with the cavitation phenomenon inside the channel quickly and effectively removes residual limescale deposits mechanically, allowing the use of less aggressive, mold-safe cleaning agents. After cleaning, the channels are automatically rinsed with water and dried with compressed air.

METHODOLOGY: in accordance with PN-76/H-04602 (PN-EN ISO 11463:2010). Material samples are immersed in 10% solution of DS1 cleaning agent heated up to 50°C, at atmospheric pressure. All samples have surface area = 40 cm². Weight loss was measured in 1h cycles for 5 hours, then the sampes were left in the solution in ambient temperature and their weight loss was measured after 24h.

Case studies

Thermovision analysis of parts in production circle and after 6 hour of mold cleaning

Flow rate values before and after cleaning

Thermovision analysis of parts in production circle and after 4 hour of cleaning

Flow rates before and after cleaning