An evaporator is a device used to separate some sort of solvent from a mixture of materials. Solutions need to be broken down into more purified compounds, so evaporators will remove the undesired component through a variety of means. Most often, the device is used to obtain water from some sort of mixture, such as saline water. However, the application can also be utilized in the separation of liquids from solids for the purpose of isolating the solid.
Basically, evaporators are used as part of the overall processing of substances in the field of materials science. Most readily, they seen as one of the steps of chemical or food production. Evaporators can be used to concentrate and purify solutions with the goal of limiting the volume of finished products and removing impurities for safer storage and consumption. In this way, the costs associated with the transport and processing of larger volume materials can be mitigated by simply evaporating the liquids from a product.
The process of evaporation is different than drying, due to the fact that the finished product can still maintain a certain volume of concentration. Many different types of evaporators are used to create this effect. An air evaporator uses heat to stimulate the molecules within a product, causing liquid to leave the material and enter the surrounding air, leaving only a concentrate. A vacuum evaporator uses the concept of forced liquid removal, creating a pressurized containment unit that physically separates solvents. Using a similar concept, a refrigerator evaporator causes liquid to be removed using the natural dehydration techniques of cold, known as crystallization.
There are a number of problems with using an evaporator, most readily seen within the food industry. Depending on the content of the material being evaporated, the overall efficiency of an evaporator can vary. Viscosity also has a alternating effect on the machinery itself, requiring different levels of pressure and power to pump materials through the process. Hard deposits can cause fouling, excess foam can develop due to heating, and acidic compounds often suffer from corrosion.
Many different companies produce evaporators designed for a large array of uses. Besides the food industry, evaporators are used in air conditioning, heating and chemical production. Automobiles used evaporators to purify petroleum and ships have systems of evaporators to keep potable water aboard for crew members. Each of these different devices come in a wide range of sizes and shapes.