1 solid conduction. The glass bottle bottom and the shelf contact portion are transferred to the bottom of the glass bottle, and pass through the bottom portion of the bottle and the frozen portion of the product to the sublimation interface.
2 radiation. The lower surface of the upper shelf and the upper surface of the lower shelf radiate to the upper surface of the glass bottle and the product drying layer, and then reach the sublimation interface through the heat conduction of the glass bottle wall and the frozen layer or the dried layer.
3 convection. Convective heat transfer through the residual gas between the surface of the shelf and the outer surface of the glass bottle. Since there is a heat transfer temperature difference in heat transfer, and the heat transfer temperature difference of each section is proportional to its corresponding thermal resistance, the temperature distribution shown in Figure 6 (b) is formed in the product. For example, the surface temperature of the shelf is 50 ° C, the temperature to the sublimation interface is about -25 ° C, the high temperature of the ice layer is about -20 ° C, and the surface temperature of the upper layer of the drying layer may be 25 ° C.
When the product is sublimated, it is subject to the following temperature limits.
1 The temperature of the frozen part of the product should be lower than the temperature of the product's common melting point.
2 The temperature of the dried part of the product must be lower than the high temperature (not charred or denatured) allowed on the surface of the dried layer.
The temperature of the 3 sublimation interface should be lower than the disintegration temperature of the product.
When the liquid product freezes, the concentrated solute "skeleton" structure, when the temperature of the sublimation interface rises to a certain critical value, its rigidity will decrease and collapse, forming a barrier layer that prevents the sublimation water vapor from escaping, and the sublimation rate is slowed down. If the heat is required to be reduced, if the heating is not rapidly reduced and the temperature of the sublimation interface is lowered, the product will be overheated and melted and scrapped. This critical temperature is called the disintegration temperature. So it is important to know the disintegration temperature of the product.
The disintegration temperature is mainly determined by the composition of the solution. Too low a disintegration temperature will prolong the drying time and may not be achievable by the ability of the equipment. This can increase the disintegration temperature by selecting suitable additives. When the solid food is lyophilized, in order to avoid denaturation of the surface of the dried layer due to excessive temperature or burnout of the surface of the dried layer, the temperature should be limited to a certain full value.
Flower Type LED Operating Lamp
The flower type surgical lamp is designed at 2016, when it was been pushed into the market, it has good echo from the customers, because the flower type surgical lamp outlook is different with normal round types lamps, its outlook is just like a flower, it is very beautiful , also can add beauty in the operation room, the flower type ot lamp change the normal condition for baldness operation room style, can make doctor and patients feel much difference; for the flower type surgery lamps specification, it is almost same as round type surgical lamp, in the first year, it also has good selling;
Flower type surgical lamp also has three types, ceiling types which include single dome, double dome , with camera or without camera; wall type and mobile type flower operation lamp;
LED Ot Lamp,LED Operation Lamp,LED Surgery Light,LED Surgical Light
Shandong Lewin Medical Equipment Co., Ltd. , https://www.lewinmed.com