Vacuum drying at a new stage

Vacuum oven technology explained by a veteran expert. Read about its use, application, technical specialties and more in this Memmert exclusive interview.

Memmert: Hello Mr. Bayer, you have been part of the Memmert family for 35 years and know the product portfolio like the back of your hand – or maybe even better! You have already told us that the VO vacuum oven is one of your favorite products. Why?

Heinz Bayer: Over the last few decades, I have, of course, come to appreciate the many advantages of all our products, but the VO is one of my favourites. The Memmert vacuum oven VO has long term stability and is robust that almost no maintenance is required, and user failures are very limited. In addition, we, at Memmert, were the first on the market with this product to introduce digital vacuum control and removable, directly heatable thermal sheets. With that, we set the bar very high in the market – and have done so to this day!

Memmert Technical Sales Manager, Heinz Bayer, is an expert on Vacuum ovens, their use, features, advantages and more.

Heinz Bayer, Head of Technical Sales.

Memmert: What is a vacuum oven actually needed for?

Heinz Bayer: A vacuum oven is primarily used for gentle and rapid drying of a wide variety of materials and goods. In the electrical industry, for example, components or printed circuit boards are dried, in medical technology, for example, a vacuum oven is used to dry titanium powder for orthopedic materials. Vacuum ovens can also be found in the food industry, e.g., for the production of dried fruit, to test the preservation and dehydration of food or to develop quick and gentle variants for this. The pharmaceutical industry needs vacuum ovens for drying medicines, powders and granules and, for example, for determining the moisture content for quality assurance.

Memmert: And why aren't conventional drying ovens used for these processes instead of a vacuum oven?

Heinz Bayer: There are many materials that are not heat-resistant and therefore cannot be dried quickly in a drying cabinet. Reducing the pressure inside the vacuum oven lowers the boiling point of water. Water normally only evaporates (depending on the ambient conditions) above approx. 100 °C. Depending on the pressure set, the boiling point in the vacuum oven changes. At a pressure of approx. 50 mbar, the boiling point of water is already 33 °C. This means that the load can be dried very gently with a Memmert VO without being exposed to high temperatures that could damage the load.

Load can be dried very gently with a Memmert VO without being exposed to high temperatures that could damage it
Memmert vacuum oven VO.

Memmert: A vacuum oven is therefore an important part of many research and manufacturing processes in a wide variety of industries. Why should users rely on the VO from Memmert?

Heinz Bayer: Memmert has been developing and producing vacuum ovens since 2000 - thanks to many years of experience, we are experts in the field of vacuum drying. Memmert offers the vacuum oven in three sizes (29, 49 and 101 liters interior volume). The setting temperature range is +20 to +200 °C and a vacuum of 5 to 1100 mbar can be set for all sizes. In comparison to other manufacturers, Memmert does not use four-sided heating on the outside of the chamber in the vacuum oven, but directly heated thermal sheets.

Intelligent direct heating via individually positionable thermoshelves

Intelligent direct heating via individually positionable thermoshelves.

This enables direct contact between the heating (thermo sheets) and the load, which ensures that the heat output is transferred directly to the load. Inside the vacuum oven, there is no medium such as air that can transfer heat to the load, which is why direct contact with the heater is so important. The heat-up time of the thermal sheets is short, and the temperature distribution is very even and precise, so that precise heat transfer can take place. By the way, we recently published a detailed whitepaper on this topic.

Memmert: But it's not just the thermoshelves that are unique, the pump module too, right?

Heinz Bayer: That is correct. To generate the vacuum, Memmert optionally offers a noise-insulating pump module with an installed vacuum pump, which consumes 70% less energy than conventional vacuum pumps. Conventional pumps run continuously at full power, whereas the speed-controlled vacuum pump in the Memmert pump module switches off as soon as the desired vacuum value is reached. In the long run, this, of course, saves energy costs and extends the service life of the wearing parts installed in the vacuum pump, such as the membrane for generating the vacuum.

Memmert: And how is the entire process in the vacuum oven controlled?

Heinz Bayer: The intuitively operated Memmert software AtmoCONTROL enables the programming of different temperature and vacuum setpoints. In this way, users can program an individual sequence of the process, which can, of course, also be saved in order to play it back at a later point in time. In addition, protocols of the process are created, which are important for the evaluation of the tests carried out and also for the audits to be carried out, especially in the pharmaceutical industry, but also in other sectors. With AtmoCONTROL, each individual thermoshelf can also be calibrated and adjusted in the event of temperature deviations.

Memmert: Finally, how would you briefly describe why the Memmert vacuum oven VO is the ideal solution for drying applications?

Heinz Bayer: The VO is a combination of proven Memmert quality and innovative technology. The directly heated, removable thermal sheets and the electronic and, therefore, programmable vacuum control meet all the requirements of very sensitive materials that are often difficult to dry.