How does the four-ring freeze-drying experimental freeze-drying machine solve the temperature adjustment without setting the temperature adjustment unit

The principle of the four-ring freeze-drying laboratory freeze-drying machine: Freeze-drying refers to the process of removing moisture or other solvents from frozen biological products by sublimatio.
Sublimation refers to a process in which solvents such as water, like dry ice, change directly from a solid state to a gaseous state without changing its liquid stat.
The freeze-dried product is called lyophilisate, and the process is called freeze-dryin.
In the freeze-drying process of the four-ring freeze-drying experimental freeze-drying machine, the temperature needs to be controlled within a certain range of process requirements during the cooling and pre-freezing of liquid items and the subsequent sublimation of moisture in solid items, which requires the freeze-drying machin.
It has a certain precision temperature adjustment functio.
How to better solve the temperature adjustment problem without setting up a temperature adjustment unit, the specific scheme is as follows:In order to provide a surplus of cooling capacity of the refrigeration compressor, add a line next to the refrigeration system pipeline that supplies cooling to the front box Refrigeration branches that can provide appropriate cooling capacity to meet the cooling capacity requirements during temperature regulation;At the same time, during temperature regulation, the refrigeration compressor is supplying cooling to two evaporators with different evaporating temperatures, and the difference in working conditions may Due to the lag of the expansion valve control, the refrigeration compressor has a greater impact, and in severe cases, it may lead to the liquid shock of the refrigeration compressor and cause failur.
This requires a good grasp of the control of the return steam pressur.
An electromagnetic valve is added to the return line of the compressor, and the pressure difference between the front and rear of the electromagnetic valve is monitored by the pressure controller to control the opening or closing of the valve to reduce the load impact during temperature adjustment and ensure the smooth operation of the compressor;In order to To prevent the pressure in the front box evaporator from rising due to the closing of the electromagnetic valve, and the temperature adjustment effect cannot be guaranteed, the technicians added a steam return branch pipe to the return steam pipeline before the electromagnetic valve, which is connected to the refrigeration compresso.
The second-stage compressed suction pipe, through the practice on multiple low-temperature vacuum freeze dryers, the results have proved that this treatment plan is feasible, it can not only avoid the increase of the cost of adding a temperature control unit, but also solve the problem that is now commo.
The capillary temperature regulation adopted causes unsatisfactory temperature regulation effect and load impact on the compresso.