JPS59191880A - Vacuum freezing drier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a vacuum freeze dryer, and more particularly to a device that achieves economical performance by using waste heat of a refrigerator as a heat source for sublimation heat supplementation. be.

[Prior art]

A conventional technique related to a vacuum freeze dryer will be explained with reference to FIGS. 1 and 2.

In the case of FIG. 1, the material to be dried 10 must first be placed on the drying rack 9 and pre-frozen. This is carried out by cooling the drying shelf 9 through a refrigeration cycle consisting of the pre-freezing butterfly, the compressor 1.1jpf compressor 2, the expansion valve 5, and the cooling coil 12. Generally, the freezing temperature at this time is -40'C or lower.

When freezing is completed, close solenoid valve 4 and close solenoid valve 6.
Open the cold trap 13 and switch the refrigeration cycle.
Cool for 41 minutes. After the cold trap has been sufficiently cooled, the vacuum pump 14 is started.

When the inside of the freeze-drying chamber 8 becomes very cold, the moisture in the material to be dried 10 begins to sublimate. Most of the sublimated water is collected in the cold trap 13. In order to continue subliming the moisture in the dried vlJ 10, it is necessary to apply heat equivalent to the heat of sublimation, and the heating heater 11
is incorporated into the drying rack 9 for this purpose, and is controlled by a temperature regulator (not shown) to maintain the temperature of the drying material 10 at a suitable level.

However, this heat of sublimation is extremely large, requiring a capacity comparable to that of a cold trap's cooling heat dragon, which has the disadvantage of increasing operating costs.

In the case of FIG. 2, when heating and cooling the drying rack 9, the cooling coil 12 is provided in the cooling heat exchanger 20, the heating coil 11 is provided in the heating heat exchanger 21, and the circulation pump 22 is the same. Therefore, like the above-mentioned one, it has the disadvantage of high operating costs.

[Purpose of the invention]

An object of the present invention is to heat a drying rack without using a large-capacity heater.

[Summary of the invention]

Based on the hint that the latent heat of sublimation of the material to be dried is balanced with the cooling heat of the cold trap, we came up with the idea of using the exhaust heat of the refrigerator that cools the cold trap.

However, if the discharged gas of the refrigerator is used as it is for heating, the amount of heating will be large due to the human power of the compressor and the heat loss to cold traps, etc., so it is necessary to limit the amount of heat used. did.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In place of the heater 11 in FIG. 2 of the prior art, a heating coil 19 is provided, and hot gas from the refrigeration cycle is passed through this during vacuum drying operation.

In the drying process, after the cold trap 13 has been sufficiently cooled and full operation begins, the flow of the refrigerant in the refrigeration cycle is controlled by closing the solenoid valve 18 and opening the solenoid valve 17. (generally about 100C) first enters the auxiliary cooler +5, where it is cooled down to the optimum temperature for the high pressure by controlling the rotation speed of the fan 16, etc. Next, this refrigerant gas is transferred to the heating coil 19 in the heating heat exchanger 21.
Here, heat is applied to the heat medium circulating through the circulation pump 22 and the three-way valve 23, and the heat medium is condensed and liquefied. If the heat medium is heated at the temperature of the refrigerant in this condensation process, overheating deterioration of the heat medium can also be prevented.

Next, the liquefied refrigerant passes through the electromagnetic valve 6 and the expansion valve 7, is evaporated and cooled in the cold trap 13, and returns to the compressor 1 again.

Since the heat pump heat amount of the refrigerator is almost equal to the evaporation heat amount, excluding the superheat amount (the heat amount removed by the auxiliary cooler 15), the refrigeration cycle is balanced and the heating heat of the drying rack 9 is sufficiently supplied.

In FIG. 4, when cooling the drying rack 9, the cooling coil 1
2, and when heating, the heat medium heated by the heating heat exchanger 21 is heated as a single stream.
r'! This is a first embodiment of the present invention that operates in the same way as the case shown in FIG. 73.

〔Effect of the invention〕

According to the present invention, since the waste heat of the refrigerator is used to generate heat equivalent to the heat of sublimation of the material to be dried,
It's economical and doesn't mean 2 is 8.

Furthermore, it has the effect of pre-cooling the discharge gas of the freezer to optimize the amount of heating, and at the same time, preventing deterioration of the heat medium due to high-temperature heating.

[Brief explanation of drawings]

? Figures p1 and 2 are cycle diagrams of a conventional vacuum freeze dryer, and Figures 3 and 4 are cycle diagrams of a vacuum freeze dryer according to the present invention. 1... Compressor 2... Condenser 4.6.17.18
... Solenoid valve 5,7... Expansion valve 8... Freeze drying chamber 9... Drying shelf 10... Material to be dried 11...
Heater 12... Cooling coil 13... Cold trap 14... Vacuum pump 15... Auxiliary cooler 19... Heating coil 20... Cooling heat exchanger 21... Heating heat exchanger 22 ...Circulation pump 23
...Mikata Bento 1m KayazfJ 1st group

Claims (1)

[Claims] In a vacuum freeze dryer in which a cooling device for freezing, a heater, and a cold trap are housed in a vacuum container and connected to a cooling 6K refrigeration cycle, a heat medium heated by the discharge gas refrigerant of the refrigerator is flowed into the heater. A vacuum freeze dryer characterized in that it can be connected.