Welcome to visit Beijing Songyuan Huaxing official website!
E-mail: sales@bjsyhx.com.cn
Product List
Breaking News
What are the advantages of a laboratory freeze dryer used in a laboratory over conventional methods?
The laboratory freeze dryer uses the physical principle to freeze the moisture in the compressed air to below the dew point, so that it can be precipitated from the air....
Analysis on the drying principle of freeze dryer
I believe everyone is familiar with freeze dryers. Such a machine that integrates freezing and drying has been favored by most experiments. The principle of freeze drying of freeze dryers is actually not complicated. Freezing and drying are divided into two processes. ...
How to properly maintain an industrial vacuum freeze dryer?
Industrial vacuum freeze dryer is composed of refrigeration system, vacuum system, heating system, electrical instrument control system. ...
What is the control system of industrial vacuum freeze dryer?
The control system of industrial vacuum freeze dryer is the command mechanism of the whole machine....
Analysis of periodic inspection and maintenance methods of pilot freeze dryer
Repair and eliminate the leakage and failure of the refrigeration system, vacuum system and heating system, and check whether the indicators of the pilot freeze dryer are in a normal state;...
Contact Us
Beijing Songyuan Huaxing
Service Line:+86-13161061291
Song Yuan:+86-13161061291
Address:C706 Changyin Building, NO.88 Yongding Road, Haidian District, Beijing, China
Email:sales@bjsyhx.com.cn
Facebook:SYHXfreezedryer
Your Location: Home >> News >> Enterprise dynamics >> How to control the pressure during the operation of the freeze dryer?

How to control the pressure during the operation of the freeze dryer?

Release Date: 2020/11/6 14:16:49 .
Browse: 420

  There are still many problems to be solved in the freeze dryers on the market. With the advancement and development of science and technology, these problems will be solved one by one. The function of the freeze dryer is to cool the material containing a large amount of water or other solvents in advance and freeze it into a solid, and then under a certain vacuum condition, the water or other solvents in it are directly sublimated from the solid in the form of vapor, and the material It is left in the ice shelf when it is frozen, and the material after the drying equipment has the same volume as before drying but is loose and porous, and has good rehydration.
  Freeze dryer is mainly composed of control system, vacuum system, refrigeration system and circulation system. In addition to the above components, the pharmaceutical freeze dryer also has hydraulic system, in-place cleaning system and in-place sterilization system. As the key equipment in the production process of aseptic freeze-dried preparations, due to the particularity of drugs, relevant departments have made clear regulations on the materials and performance of freeze-drying machines. Although the current freeze dryer meets the production requirements, there are still some shortcomings in terms of economic benefits, product quality, and production operations. The most important point is that the vacuum is too high, which is not conducive to product sublimation.
  In the freeze-drying process of the product, the vacuum degree of the environment has a direct influence on the length of the freeze-drying cycle. If the vacuum is too low, the sublimation rate will decrease significantly; if the vacuum is too high, the freeze-drying rate will decrease significantly due to poor heat convection conduction. Therefore, various methods must be adopted to control the pressure in order to achieve the best conditions for product drying. The main methods of pressure control are:
  1. Separating valve control method
  2. Water vapor condenser control
  The water vapor condenser control method refers to an operation method that increases the temperature of the water vapor condenser surface to reduce the condensation capacity, resulting in an increase in the partial pressure of water vapor in the drying box, thereby achieving the purpose of pressure control.freeze dryers
  3. Small butterfly valve control method
  Small butterfly valve control method refers to the purpose of controlling the pressure in the tank by opening or closing the valve between the water vapor condenser and the vacuum pump intermittently. The small butterfly valve control method uses the signal from the control system to control the opening and closing of the valve. When the pressure is higher than the set value, the valve is opened; when the pressure is lower than the set value, the valve is closed. However, if the temperature of the condenser is very low at this time, the temperature of the product shelf is also very low. As the sublimation rate slows down, the partial pressure of water vapor continues to decrease. At this time, the indoor pressure of the freeze spray drying equipment is already lower than the set value. , But because this method cannot increase the indoor pressure, the purpose of adjusting the pressure cannot be achieved.
  4. Aeration method.

share to:
Songyuan Freeze Dryer logo
Address:C706 Changyin Building, NO.88 Yongding Road, Haidian District, Beijing, China
Hotline:+86-13161061291
Email:sales@bjsyhx.com.cn Facebook:SYHXfreezedryer
Fax:+86-10-58895379