Portable vacuum oven.
How does it work?
In four steps.
The MeltPrep VChamber turns any hot plate into a vacuum oven. It is designed to be easily installed on existing hot plates, e.g. lab heaters or measurement devices. Our solution brings the vacuum to the sample and not the other way around.
Vacuum heat treatment
Powder or extrudates pellets, flakes etc.
Silicon Petri dish or aluminium pan
The process can be split up in four easy steps. (1) The materials (powder, extrudates, pellets,…) are placed on the hot plate. (2) The VChamber forms a tight vacuum chamber around the sample and is evacuated. (3) The vacuum heat treatment at parameters of dry, temper, or melt the sample is set. (4) Finally, the vacuum is relieved and the VChamber can be removed.
What do you need to know?
The theory of drying.
In most cases, the moisture of hygroscopic materials should be removed. Simply put, the moisture from the environment is taken up and is either deposited on the surface or absorbed by the material. Drying means the removal of unwanted moisture from a solid material.
The mass transfer basics
Surface water quickly evaporates or boils off from particle surface. The bottle neck in drying is typically diffusion. When moisture is absorbed by the material, diffusion needs to bring the water molecules back to the surface of the solid particles.
Diffusion inside the particle
Evaporation or boiling
The general rule is: the bigger the particle, the longer the drying time as the diffusion path length increases. Micronized powder will require minutes whereas millimeter-sized particles will take hours to fully dry.
Apart from that, diffusion speed depends on the concentration gradient and temperature. Both can be maximized within the VChamber. High vacuum levels can be established within seconds and it is resistant to temperature levels up to 300°C. This makes the VChamber the fastest drying chamber on the market.
Drying Speed Scale
Boiling on hot plate
Why using a vacuum?
Desiccator vs. VChamber
Vacuum drying in a generic desiccator takes out energy from the material and the drying process is slowed down by temperature reduction (heat of evaporation). It can lead to freezing of water which basically stops the drying process as sublimation is the slowest transition into gas.
Phase Diagram Water
Glass fibre reinforced PTFE foil
Vacuum + Heat
Heating the material in a VChamber significantly shortens the drying time as the temperature is kept constant or can even be increased. Direct heat transfer from the heated plate enables fast cycles, and thanks to the compact and varied size options, a perfect sample to vacuum oven ratio are guaranteed. Thus, moisture can be removed quickly.
What are the typical applications?
The MeltPrep VChamber is an all-purpose vacuum chamber, specially designed for professional use in the pharma, food and plastic industry. Typical applications are drying, melting and tempting of powders, pellets or granulates.
Most material characterization methods will deliver falsified results when moisture is within the sample. Moisture overlaps phase transitions in thermal analysis or forms bubbles changing the mechanical properties.
Glass transition TG
Gentle drying below TG
Normal boiling point
Processing / Characterization
In processing moisture is also undesirable. In extrusion, foams might be formed at the outlet as the pressure suddenly decreases, and water vapor can expend. Gentle vacuum drying at the elevated temperature inside the VChamber resolves this issues.
Vacuum Drying + VCM Processing
VCM sample with bubbles, from moist pellets
Discs Ø 25 mm
VCM perfectly homogeneous sample, from VChamber dried pellets
Vacuum drying on small particles can fluidize the complete powder bed. The evaporating moisture stream is fast enough to lift the particles and make them behave like a fluid. The drying speed is maximized at gentle temperatures as heat is supplied by hot plate and moisture discharged by the vacuum pump. The short video shows an example of moisture removal from a polyethylenoxid powder.
Is there anything else?
See for yourself.
There are bottomless application fields apart from the typical ones. The VChamber can also be used for moisture removal from sensitive products like electronics, storage of oxygen sensitive material or solvent removal with the usage of capillary effects as well as for customized applications.
Dry - non hygroscopic powders can be molten within the VChamber directly. The air between the particles will be removed when vacuum is applied, and the particles can fuse to a homogeneous melt.
When moist powders have to be molten, a combined approach of drying at temperatures below the melting or glass transition point is recommended to remove the moisture, otherwise, the moisture is trapped during the melting and can not escape from the sample material.
After injection, molding residual stresses may remain inside a-part. Stresses relax faster at elevated temperatures, but oxidation also might occur. Vacuum reduces the risks of relaxation significantly and thanks to the VChamber, the parts are located on the temperature-controlled plate directly enabling fast heating and evacuation cycles for applications where this is critical.
How is it build up?
MeltPrep stands for user-friendly, high-quality products. And that’s how the VChamber is designed as well. Its main body is made of aluminum coated with nickel to make it lightweight and resistant to mechanical and chemical wear. The glass lid is a borosilicate glass to create a long lasting and reliable product.
Vacuum relief valve
One of the key distinctions of the MeltPrep VChamber compared to other vacuum ovens, and other solutions is the bottomless design. It allows the preparation of a sample right on the hot plate of a measurement device. The VChamber seals directly to the hot plate, allowing a direct heat transfer from the hot plate to the sample.
The VChamber is designed for continuous operation up to 200°C. For short term applications temperatures must not exceed 300°C. At the lower end -20°C can be reached when required. Thanks to the thermally isolated handles you can easily operate it without gloves.
Size matters. Choose the size that fits your hot plate and application to prevent unnecessary long cycle times.
The VChamber seals at your hot plate directly. Temperature resistant X-rings ensure reliable sealing and act as thermal isolators to minimize heat transfer between VChamber and hot plate. Thus, the heat is sufficiently directed towards the samples.
The control system integrated into the hot plate, regulates the temperature of the plate. Samples, located on the hot plate, reach the set temperatures almost as fast as your hot plate. The VChamber is thermally isolated from the hot plate to minimize thermal inertia. It is available in 3 dimensions to enable fast evacuation and purge as well as temperature cycles.
The VChamber is designed to simplify daily lab routines as well as challenging new tasks. There are various reasons why there should be VChamber in every lab. But we know your time is valuable, that’s why we are just presenting the four main aspects in detail.
What are the advantages?
Cost effective solution
Direct heat transfer
Simplicity is an art only very few people understand. As Albert Einstein already said, "Everything should be made as simple as possible, but no simpler.” We take him at his word and made it our mission to create simple products and simple explanations to help you save your time and nerves.
What is your motivation?
One of the core features of the VChamber is its bottomless design, which on the one hand, enables mounting it on every hot plate and on the other hand, allows to prepare the sample in-situ without error-prone sample moving.
Two advantages in one.
The VChamber consumes very little space within the laboratory compared to conventional vacuum ovens and can be used highly flexible in different places thanks to its handy design and adaptability.
Even for small labs.
Requires 1 m lab bench
The VChamber seals directly to the hot plate, allowing a direct heat transfer from the hot plate to the sample. Fast temperature changes are possible allowing short drying times and reducing the risk of degradation to a minimum.
Direct heat tranfer
Cost effective solution
When it comes to figures, the VChamber has one big buying argument. You can use your already existing elements in combination with the VChamber family. Bring vacuum drying to your lab for a fraction of the costs for a conventional system.
What can it be used for?
For more than one expects.
The materials can be melted directly on your existing hot plate, which gives you the opportunitiy to proceed right on and prevents moisture uptake and aging effects. For example, samples can be molten on your rheometer under vacuum directly. Subsequently, the VChamber is removed and one can proceed with the measurement.