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Freezing to perfection – CRYOFLEX freezers from Linde.pdf
Our sub-zero freezers use liquid nitrogen to cool down parts inside a treatment chamber. The liquid gas is sprayed through fine nozzles into the chamber, where it evaporates quickly and thus lowers the temperature. This optimises the parts’ microstructure, transforming retained austenite into martensite. The temperature profiles are measured and precisely controlled by two sensors, making this method the ideal fit for the demanding requirements of aviation, aerospace and automotive industries.
In addition to liquid nitrogen, we offer specially engineered cryogenic cooling equipment. You can choose from our four off-the-shelf CRYOFLEX® freezers – our cabinet, box, tunnel and further continuous models.
Complementing this standard offering, we also design customised models in various standard and tailored sizes to meet your specific efficiency, heat loss and gas consumption needs.
Our CRYOFLEX C cryogenic cabinet freezer is designed for processes where temperatures close to that of liquid nitrogen may be necessary. It is ideally suited to batch production with front loading. An electric cryogenic valve controls the injection of liquid nitrogen (LIN) into the cabinet. Depending on the size of the freezer, it comes with up to three fans inside the chamber to ensure extremely uniform temperature distribution, allowing for optimum performance and efficiency. Standard temperature range: room temperature to –150°C.
To cool down moving blade strips more effectively, we developed the CRYOFLEX CC continuous contact cooling solution. Up to eight strips can be cooled in parallel and the total length of CRYOFLEX CC can be adapted to the feed rate of the overall line. Standard temperature range: room temperature to –160°C (cooling plate).
Customer: Based in Eisfeld, Germany, Feintechnik is one of Europe’s leading manufacturers of quality razors and razor blades, specialising in private label shaving systems and disposable razors. With its “made in Germany” seal of quality, the company is constantly refining its product technology, always with a view to producing precision products of the highest standards. To produce these razor blades, Feintechnik operates four heat treatment systems for stainless steel.
Challenge: After the hardening step, the razor blades are cooled down to 25°C. Subsequently, a sub-zero treatment transforms retained austenite into martensite. Feintechnik operated compressor-based systems for this step. However, these offer limited performance as they can only cool parts down to minus 80°C. In addition, these systems are subject to strong fluctuations in efficiency, depending on the surrounding temperature. Consequently, many of these systems do not reach their maximum performance if the surrounding temperature is elevated. In addition, compressor systems can be prone to heavy icing inside the cooler. This further compromises overall operational efficiency. Maintenance was also an issue for Feintechnik. Typically, the company had to call in a service technician three or four times a year to top up refrigerant and replace frozen valves and compressors.
Feintechnik was keen to overcome these challenges. On the one hand, it wanted to increase productivity and efficiency. It was therefore looking for an innovative technology that would enable it to cool razor blades faster to a lower temperature. There are two ways to increase throughput – either extend the cooling line or switch to a cooling line that offers faster results. And, on the other, Feintechnik wanted to put reliable, low-maintenance technology in place that would reduce high refrigerant losses and the number of visits from service technicians.
Feintechnik decided that the best way to meet all of these demands was to invest in a new heat treatment system and equip this with Linde’s cryogenic cooling technology. It would increase cooling speed by quickly reducing the temperature of hardened parts to below minus 100°C while also reducing maintenance effort and cost.
“CRYOFLEX® CC from Linde has enabled us to increase both productivity and quality while also reducing maintenance effort and contributing to climate protection by avoiding ozone-depleting substances. We are very happy with our decision to go with CRYOFLEX CC and plan to roll out more of these systems moving forward.”
Simon Artschwager, Production Engineering at Feintechnik GmbH Eisfeld, a Harry’s, Inc. company
Find out how Linde was able to resolve these challenges
In a continuous heat treatment process, operators are keen to avoid unnecessary handling and transportation of parts requiring sub-zero treatment. To accomplish this, we have developed a continuous conveyor belt in a sub-zero tunnel called CRYOFLEX T. This freezer can be easily integrated into continuous hardening lines. It is well suited to mass production of small or thin parts such as injectors, springs, nuts and bolts. Standard temperature range: room temperature to -110°C/-166°F
Our CRYOFLEX B cryogenic box freezer is designed for processes where temperatures close to that of liquid nitrogen may be necessary. The box is ideal for small production batches and is loaded from the top. In the freezer, the injection of liquid nitrogen is controlled via an electrically operated cryogenic valve. Standard temperature range: room temperature to -180°C/-292°F (liquid nitrogen).