_ used in vacuum freeze drying system

the vacuum system consists of vacuum container, vacuum pump, vacuum valve, vacuum gauge, vacuum sealing, condenser and the pipeline.

a. The basic requirements of vacuum system

( 1) According to the needs of freeze-dried materials, should be able to reach a certain degree of vacuum and vacuum degree of work. Limit vacuum is without leakage system can achieve the minimum pressure; Work can stay in the process of vacuum is in a vacuum.

( 2) Under the condition of as much as possible to improve the effective pumping speed, shorten the flush time, reduce the cost of freeze-dried products.

( 3) System structure is simple, strong, easy to operate, easy to maintain.

2. Vacuum sealing system

there are two kinds of vacuum seal, one is a metal or ceramic permanent seal or glass and metal welding; The other is a removable static seal and dynamic seal. Static seal through connection and after sealing parts remain still; Dynamic seal must ensure that the movement and seal.

removable vacuum sealing, must be in the middle of the component connection flange sealing material, through repression, fastening to achieve sealing. Can choose different according to vacuum sealing material. Common seal material are: rubber, four hydrogen ethylene, soft metal aluminum, oxygen-free copper, etc.

vacuum grease used in vacuum sealing and lubrication between two smooth surface. Vacuum sealing wax used for filling in the vacuum system leakage. Vacuum seal was divided into vacuum mud and vacuum wax.

3. Drying oven

drying oven is one of the important part of vacuum system, the vacuum performance will affect the whole performance of the refrigerator. It is a vacuum chamber and the container of freeze-dried materials.

4. Siamese

header is one of the container vacuum system, the role of capture water vapor from the sublimation of material to protect the vacuum pump. Also known as trap trap, the condenser and the cold trap.

5. Vacuum and vacuum valve

in the drying chamber and the water catchers, water traps have between vacuum pump and vacuum tubes, and to provide a vacuum valve to control the opening and closing, minimum flow, etc.

according to the working strength of the valve, vacuum valve can be divided into low vacuum valve, high vacuum valves and vacuum valves. Therefore, the choice of the vacuum valve mainly depends on its use and use condition, the model size, it depends on the diameter of the pipe.

6. Vacuum measurement

vacuum is usually expressed as a pressure. Therefore, vacuum cone due to pressure measurement in vacuum environment. Vacuum measurement is important and closely related to the same part of the vacuum technology. The traditional vacuum measurement method is directly measured pressure. For example, a u-shaped tube vacuum gauge ( For example McLeod gauge) Used to measure the I vacuum. It still apply, but it does not apply to contain condensable gas molecular environment and automatic control system. Vacuum is basically a molecular density is small, the number of less, the density of gas molecule has its own physical properties, such as heat conduction and conduction, according to these features a variety of vacuum gauge is designed.

vacuum freeze-drying system gas pressure in the range 105 - general 1 pa, but often have the non-condensable gas, such as water, oil vapor, often accompanied by changes in temperature and equipment throughout uneven temperature, still exist in some of the technological process of unsteady gas flow orientation. So should be paid attention to when choosing vacuum gauge and measure the actual process conditions, its influence on the measured value.

is suitable for the vacuum freeze drying technology application plan have McLeod gauge, film ionization vacuum gauge, resistance vacuum gauge, vacuum gauge, etc.