JPS608303Y2 - Freeze drying equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention mainly relates to a freeze-drying device used for freeze-drying samples in physical and chemical experiments.

When freeze-drying a sample, in order to improve drying efficiency, a small amount of the sample is placed in a container such as a sample bottle or test tube, and the sample is frozen by spreading it thinly on the wall of the container.Next, a predetermined amount of the sample is poured into this container. The method is to freeze-dry it.

Conventionally, this pre-freezing and freeze-drying uses a dedicated freezing tank and cold trap, and these are cooled by separate refrigerators, so two independent refrigerators are built into a single device. As a result, the entire device becomes larger.

It cannot avoid the drawbacks of being heavy and expensive.

Additionally, when ice forms in the cold trap, the use of water or hot water is undesirable due to the built-in vacuum exhaust system, so operation is stopped and the ice is allowed to thaw naturally over a long period of time, reducing the efficiency of experiments. It was the cause.

In this project, the compressor and condenser of the refrigerator are common, and the evaporator for cooling the freezing tank for pre-freezing and the cold trap for freeze-drying is installed in parallel and switchable, and the compressor outlet and the cold trap are connected in parallel. By short-circuiting the evaporator inlet and the evaporator inlet, the aforementioned drawbacks were eliminated.

The embodiment of the present invention will be described below with reference to the drawings.
In addition, a check valve 8 is installed in the return pipe 5 on the freezing tank side, and the pipes 10 from the common condenser 9 are expanded by electromagnetic switching valves 11. A short-circuit pipe 17 branches off into two feed pipes 14 and 15 having valves 12 and 13 and connects to the inlet ends of the evaporators 3 and 4, respectively, and further branches off from a pipe 16 connecting the compressor 7 and the condenser 9. An electromagnetic on-off valve 18 is provided in the cold trap, and this is connected between the expansion valve 13 of the feed pipe 15 on the cold trap side and the evaporator 4.

The refrigerant pressurized and heat radiated by the compressor 7 and condenser 9 is transferred to the switching valve 1.
1 to one of the inlet pipes 14.15, the expansion valve 12.13 lowers the temperature and pressure, the evaporators 3 and 4 absorb heat, and the cycle returns to the compressor 7 via the return pipes 5 and 6. It is the same as a normal refrigerator.

Here, first, a sample of about one-third of the volume of the container 21 is put into the container 21, immersed in the liquid 19 of the freezing tank 1, and the switching valve 11
is opened to the pre-freezing side, and the refrigerant from the condenser 9 is sent to the evaporator 3 of the freezing tank 1, and the container 21 is rotated or vibrated while cooling the liquid 19.

For this reason, the sample is spread by centrifugal force on the wall of the container 21 and gradually freezes while being cooled to form a thin frozen layer 22.

Shortly before this pre-freezing is completed, the switching valve 11 is operated to send the refrigerant to the evaporator 4 of the cold trap 2 to start cooling, and a predetermined amount of the sample 23 is placed in the container 21 where the pre-freezing has been completed.
and connect it to cold trap 2, container 21
The freeze-drying is performed while the inside of the cold trap 2 is evacuated by the vacuum pump 20.

When ice forms in the cold trap 2, the switching valve 11 is placed in the neutral position to cut off the pipe 10 and the two inlet pipes 14 and 15, and the on-off valve 18 is opened to remove the high temperature refrigerant from the compressor 7. It flows through the short-circuit pipe 17 to the evaporator 4 of the cold trap 2 to melt the ice.

Note that the switching valve 11 can be replaced with two on-off valves, and the same effect can be obtained by installing these at appropriate positions on the inlet sides of the expansion valves 12 and 13 of the respective feed pipes 14 and 15, or alternatively, an on-off valve can be provided on the expansion valves 12 and 13. It goes without saying that the feed pipes 13, 14 may be opened and closed alternately, or may be closed simultaneously.

Furthermore, a switching valve may be provided at the branch point of the short-circuit pipe 17 and the pipe 16 to short-circuit the compressor 7 and the evaporator 4 during ice thawing.

As mentioned above, in this case, the evaporators for cooling the freezing tank for pre-freezing and the cold trap for freeze-drying are installed in parallel with the common compressor and condenser.
When trying to improve drying efficiency by first freezing a sample thinly and then freeze-drying it in a physical and chemical experiment, pre-freezing and freeze-drying can be performed simply by operating the switching valve or on-off valve while the common compressor and condenser are running. This can be done consecutively.

Since the compressor and condenser are commonly provided for the two evaporators, not only can the device be made smaller, lighter, and cheaper, but also the predetermined evaporation can be performed according to the freezing order. Since the refrigerant is sent to the refrigerator and the switching is performed while the refrigerator is continuously operating without starting or stopping the entire refrigerator, freezing can be performed with low power consumption.

In addition, according to this proposal, the outlet of the compressor and the inlet of the evaporator of the cold trap are connected by a short-circuit pipe, so that the refrigerant compressed by the compressor and heated to a high temperature is transferred to the evaporator of the cold trap without passing through the condenser. Therefore, when ice forms in the cold trap, the compressor continues to operate and the refrigerant is used to quickly melt the ice.
This method does not reduce the efficiency of experiments, etc., and has the advantage that a single refrigerator can be used for both cooling and heating, allowing freezing and thawing to be carried out at the same time.

[Brief explanation of the drawing]

The drawing is a piping diagram showing an embodiment of the present invention. 1...Freezing tank, 2...Cold trap, 3゜4...Evaporator, 7...Compressor, 9...Condensation Device, 11...Switching valve, 1
2, 13...Expansion valve, 17...Short-circuit pipe, 18...Opening/closing valve.

Claims (1)

[Scope of utility model registration request] Evaporators 3 and 4 that separately cool the freezing tank 1 for pre-freezing and the cold trap 2 for freeze-drying are connected to a common compressor 7.
and a freeze-drying device which is installed in parallel and switchably with the condenser 9 and further connects the outlet of the compressor 7 and the inlet of the evaporator 4 of the cold trap 2 with a short-circuit pipe 17.