The characteristic of medical vacuum freeze-drying machine is that the products are generally completed the pre-freezing, heat preservation and sublimation drying process on a group of shelves in the same drying box. Because the same group of shelves must have both cooling and heating, small freeze dryers generally use intermediate media for indirect conduction. The uneven temperature of the shelves and the poor heat conduction of the tray cause large energy consumption and long process. The failure to meet the residual water content standards in product design is a key factor that has long hampered the development of pharmaceutical companies.
Freeze dryers generally pack raw materials in trays and place them on trays for freezing, sublimation drying, and analytical drying. The thickness of the tray should take into account cold and hot deformation, so it should not be too thin, generally 1.5mm Right and left, the vial or food containing the Y product is placed in the tray at a height of about 10-15 Mm. The temperature is transferred from the hot and cold temperature of the shelf to the bottom of the tray until the upper end freezes, sublimates to dry, and analyzes the dried items. However, due to the vial containing medicine, Y product, small freeze dryer biological products or food in the tray, the height is about 10-15mm, the temperature transfer takes a long time, and the temperature of the shelf is not uniform, which causes freezing The moisture content of the dry product is uneven, and the pass rate of the residual moisture content of the product is affected.
The tray on the manufacturing shelf is made of stainless steel, and it will deform when heated and contracted for a long time during freeze-drying, so each manufacturer has spent a lot of manpower and financial resources, such as the flatness of the surface of the shelf, the surface Plug position, thermal expansion and contraction caused by intermittent welding and materials, etc., all kinds of problems will directly affect the thermal conductivity between the shelf and the product and the tray, resulting in the possibility of uneven temperature, so there are often some The residual water content in the freeze-dried vials reported by users is inconsistent, and some vary greatly, failing to meet the product design residual water content standard. Some users use drawable tray frames or bulk vials when freeze-drying vials, which is a waste of loading and unloading time, and it is easy to break when loading and unloading medicine bottles. Now, foreign countries have begun to use sterile film forming trays, but the price High, easy to damage, short use time and other defects.