Why Use a Vacuum Mixer?
A vacuum mixer is a device for mixing viscous materials in a completely air-free environment. This allows the original properties of the materials to be preserved and the quality of the finished product to be improved.
Incorporation of air can cause problems such as undesirable foaming, inhomogeneous distribution of liquid and powder phases, long process times or encapsulation of powder agglomerates. Vacuum mixing eliminates these problems.
Preparation of cements and amalgams
When preparing cements and amalgams it is important that the raw materials are properly mixed. The vacuum mixer can help to achieve this. The vacuum removes air from the mixture which helps to prevent “dusting” and floating of lightweight powders, resulting in better dispersion. It also shortens the processing time because it eliminates the need for a separate post-mixing deaeration step.
The mixing capsule assembly, which is particularly useful in preparing dental silver amalgams, comprises two tubular housing sections removably attached to each other and defining between them a first chamber for receiving a first material to be mixed and a second chamber for receiving a second material. The chambers are joined together by a partition integrally joinable to the inner surface of the tubular housing section, and the partition includes a plurality of o-rings alternating with washers.
When the capsule is filled with a predetermined amount of the solid, powdery bone cement component, it is sealed by the polyethylene ball and transferred to the cartridge mixer under a fine vacuum. A liquid active ingredient may be introduced into the filler pellets under a fine vacuum, and the vacuum mixer is used to mix and impregnate the filler agglomerates with the monomer. During this process, it is important that the monomer is chilled so that oxygen, which normally interacts with free radicals of the monomer and slows its polymerization, does not interfere with the reaction.
Dispersal of powders in liquids
In many applications the quality of a product depends on how well and how thoroughly powders are dispersed in liquids. These powders may be colour pigments, thickeners, flavours, matting agents, reinforcing fibres or fillers. The process often takes a long time due to the complex interaction between the powder particles. Using a vacuum mixer significantly reduces the mixing time and improves the dispersing result. The application of vacuum also prevents “dusting” and floating of lightweight powders, which can cause a number of problems such as product degradation, poor printability or syringe failure.
The vacuum mixer generates a powerful vacuum in its dispersing zone, which can reach up to a few millibar (absolute pressure). In the powder stream this vacuum expands the distance between the powder particles and fluidises them. This makes it possible to mix even compact and dense powders without additional fluidising air.
The Silverson Flashmix uses a revolutionary approach to powder-into-liquid mixing. Unlike common Powder-into-Liquid machines that use vacuum to pull in powders, it drives the powder into the liquid stream. This can be done with vacuum mixer all types of powders and additives, at varying temperatures and in viscous products, and it allows for fast high shear mixing without the associated problems such as agglomeration and dusting. The machine works outside the vessel and is connected to it by pipes or flexible hoses, so it can work with any container size and type.
Vacuum impregnation of filler pellets
Vacuum impregnation is a process that uses vacuum and pressure to seal leak paths or voids in metal castings or powdered metal parts. It improves machinability by stabilizing the individual powdered metal granules and improving finish quality. It also reduces tool chatter, allowing for more efficient and longer-lasting machining operations. It is used to improve the quality of powdered metal components by eliminating the fine leak paths that cause corrosion and other problems.
During vacuum impregnation, the solution containing different compounds penetrates into the matrix of the food tissue and significantly modifies or enhances its properties. These modifications can include nutritive enrichment (e.g., polyphenols, probiotics, and micronutrients), extending shelf life of the foods, and modification of sensory attributes.
Another application of vacuum impregnation is in reducing the water activity of fruit and vegetables, particularly for storage. It is believed that the improvement of capillary flow and mass exchange during impregnation with extracts may be due to an increase in surface tension at the solid-solution interface.
During vacuum impregnation, a dry powdered resin is impregnated in the voids or pores of a component under a controlled air pressure. The process is typically performed in a vacuum chamber and takes place over mixer manufacturer a specified period of time, depending on the product and its specific characteristics. The impregnating process can be performed using manual, semi-automated, or fully automated systems.
Vacuum drying
Vacuum drying of filler pellets in a vacuum mixer is an important process that helps reduce the size of the particles. This enables the product to be processed much faster and at lower temperatures, which can improve the quality of the finished product. This type of process also helps to reduce oxidation and prevent contamination. It is a very important step in the production of many products, such as rubber, plastics and composites.
Vacuum mixers are often used in food and medical production, so they must comply with strict standards to ensure safety and sanitation. They can be sterilized or come with components that can be replaced as needed to address concerns about contamination. In addition, they are often inspected by government representatives who enforce health codes and safety regulations.
A vacuum mixer can be used to prepare a variety of substances, including slurries, gels and pastes, granules, powders and liquids. In addition to preventing the integration of air into these materials, they also allow them to be dried at lower temperatures and help reduce oxidation and contamination.
A vacuum mixer can be used to mix silicone, epoxy, PDMS and other polymers, liquids, ingredients or dough in a completely free of air environment. It can also be used to remove moisture and contaminants from a sample before processing it in an instrument.