Heat sealers are devices which seal plastic packaging with the application of heat. Many industries use heat sealers to prepare products for sale, ranging in size from small businesses to large corporations which handle high volumes of material. Various styles and sizes are available from several companies which specialize in making heat sealers, along with the plastic bags to use with them.
There are two basic types of heat sealers. Automatic or continuous heat sealers use moving belts to keep up a continuous production line. Products are bagged, sent down the belt, sealed, and dropped into boxes for shipment or storage. Impulse heat sealers have a single element, and are usually designed to be operated by hand. In some instances, an impulse heat sealer is partially automated. Continuous heat sealers are much larger, and more expensive, because of their greater size and higher volume capacity. Impulse heat sealers range in price, with simple desktop versions being very affordable.
Most heat sealers are designed to be used with a range of plastics, although they may specify which plastics are safe for use. A temperature dial allows the user to control the temperature of the heating element, so that the temperature can be lowered for more delicate plastics, or raised for heavy duty plastic. As the packaging goes through the heat sealer, pressure is applied to encourage the two sides of the bag to crimp together, and the timing is controlled as well, to ensure that the plastic is exposed to the heating element for an appropriate amount of time.
A heat sealer can also be combined with a vacuum packer, as is often the case with heat sealers used in food packaging. The vacuum packer pulls all of the air out of the bag, while the heat sealer makes a tight seal, preventing the food inside from being oxidized. Many fishermen use vacuum packer/heat sealers to preserve their catch at sea, freezing the majority of the fish in the vacuum packed packages for future consumption.
Heat sealing bags come in a wide range of sizes and shapes, allowing people to package a range of things inside. The size of the heat sealing bags a company can use is limited by the length of the heating element on the heat sealer, since the entire sealing edge needs to be sealed at once for the most effective, smooth seal. Many companies also manufacture labels which are designed to fit on their heat sealing packages, for businesses which want to print their own in house.