the working principle of is to use a vacuum pump to draw out the air in the plastic bag or aluminum foil film wrapped around the product, so that the product is always in a vacuum environment, or add nitrogen or other gases, which is more helpful to increase the product. the degree of preservation greatly extends the shelf life of the product. there are also several types of pumps for , such as single-stage rotary vane vacuum pumps, industrial pumps, etc. of course, the prices of pumps configured for these types of meat nitrogen vacuum packaging machines are also different. of course, whether it is internal or external, desktop, vertical or horizontal, the selects most of the single-stage rotary vane vacuum pumps, which are also called xd rotary vane vacuum pumps. grade oil-sealed rotary vane vacuum pump is the basic equipment to obtain vacuum.