JPH0677643B2 - Centrifugal evaporator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a centrifugal evaporation device for evaporating a liquid into a vacuum evaporation tank while rotating a liquid on an evaporation surface of a rotor heated by using a heat medium.

(Prior Art) Conventionally, as a means for heating an evaporation surface rotating in a vacuum evaporation tank provided in a centrifugal evaporation device, a radiant heating method using a heater and a heating medium for circulating a heating medium through a rotor having an evaporation surface The heating method is used. The radiant heating method using a heater is prone to failure due to wire breakage or adhesion of objects to be processed, and since it is radiant heating, it is necessary to raise the temperature of the heater, resulting in high power consumption and uneven temperature. Furthermore, there is a risk of overheating, which is not preferable. On the other hand, the heat medium heating method has an advantage that heating can be controlled easily and heating can be performed without unevenness.

The device used for this heat medium heating system usually has a heater such as a heater for heating the heat medium and a heat transfer part for the heated heat medium in a circulation circuit of the heat medium connected to the heat transfer part of the rotor. A pump that circulates through and a reservoir having a space for expanding and exchanging the heat medium are provided.

(Problems to be Solved by the Invention) In the heat medium circulating device configured as described above, the heat medium is oxidized during heating, so that the heat medium is replaced in a short period of time to prevent corrosion of the equipment. In addition, the heat medium may leak and mix into the object to be processed. If the heat medium contains harmful or toxic substances, the object to be processed is also contaminated and dangerous. In the centrifugal evaporator, the heat medium circulates inside the rotor that rotates in the vacuum evaporation tank, so there is a high risk of leakage.

It is an object of the present invention to provide a safe centrifugal evaporation device that prevents oxidation of a heat medium and can be used even with a substance that easily oxidizes and does not leak the heat medium.

(Means for Solving the Problems) In the present invention, a rotor having an outer surface formed on the evaporation surface of a liquid is rotatably provided inside the evaporation tank main body evacuated to a vacuum, and a heat provided integrally with the rotor is provided. A heater having a heating unit for heating the heating medium, a pump for circulating the heated heating medium through the heating unit, and a reservoir having a space for expansion and replacement of the heating medium, in the heating unit through which the medium flows. A heat medium circulation circuit having a pipe connected to a vacuum pump in the space of the reservoir so as to maintain the entire circulation circuit in a depressurized state during heating and circulation of the heat medium. By connecting, the above-mentioned object was achieved.

(Function) The heat medium in the circulation circuit is heated by the heater and then circulated by the pump to the heat transfer section of the rotor that rotates in the vacuum evaporation tank. The inside of the circulation circuit is depressurized to, for example, 1000 Pa level or less. While maintaining this depressurized state, the heat medium is heated and circulated in the circuit by the pump, the evaporation surface of the rotor is heated in the heat transfer portion, and the liquid sprayed on the evaporation surface is evaporated. Since the inside of the circulation circuit is in a depressurized state, the heat medium is not oxidized, and therefore an easily oxidizable substance such as tempura oil can also be used as the heat medium, and further, the inside of the heat transfer part of the rotor is depressurized to the outside. The pressure difference from the vacuum pressure in the evaporation tank is reduced, and the wall thickness of the heat transfer portion can be reduced to improve the heat transfer efficiency.

(Example) The Example of this invention is described based on drawing.

In the drawings, reference numeral (1) is an evaporation tank for centrifugal evaporation, (2) is a rotary drive shaft that is provided inside and outside the evaporation tank (1), and (3)
Is a rotor having a funnel-shaped evaporation surface (3a) on the outer surface, which is rotated in the evaporation tank (1) by the drive shaft (2).

The evaporation tank (1) has a mechanical booster (5), an oil rotary vacuum pump (6), and a diffusion pump (7) via a cold trap (4) in order to evacuate the inside thereof to, for example, 1000 Pa.
Is connected to a vacuum exhaust device (8). (9) is the refrigerant passage
It is a refrigerator connected to the cold trap (4) via (10).

A heat transfer part (11) through which a heat medium flows for heating the rotor (3) is integrally formed, and the heat transfer part (11) includes a heater (12), a pump (13) and A heat medium circulation circuit (15) provided with a reservoir (14) is connected. (16) (16) is a tank that stores the stock solution to be evaporated, (17) is the stock solution flow path (1
A pump that blows onto the evaporation surface (3a) of the rotor (3) in the evaporation tank (1) through the preheater (18) of (9), and (20) is the cooling water flow path (21).
Shows the cooled cooling plate of the cooling water from, the stock solution sprayed on the evaporation surface (3a) of the rotor (3) heated by the heat medium evaporates and adheres to the cooling plate (20). The first distillate that arrives is collected in the tank (23) and sent out by the pump (24). (twenty five)
Is a heater of the heater (12).

The heat medium circulating in the circulation circuit (15) accumulates in the reservoir (14) with a space (26) above the reservoir (14) for expansion and exchange of the heat medium, and the space (26) contains oil. A state in which the pipe (28) connected to the rotary vacuum pump (27) is connected, and the heating circuit is heated by operating the vacuum pump (27) and the entire circulation circuit (15) is depressurized to 1000 Pa during circulation. I was able to maintain.

When diluting the stock solution, the evaporation tank (1) is evacuated by the vacuum exhaust device (8), the rotor (3) is heated by the heat medium of the circulation circuit (15), and then the stock solution is sprayed on the rotor (3). The heating is continued during the distillation.

When this distillation time becomes long, the heat medium is conventionally oxidized to cause inconveniences such as corrosion of equipment such as the pump (13) of the circulation circuit (15), and the heat transfer section (11) provided in the rotor (3). There was a risk of leakage into the evaporation tank (1) due to damage, etc., but by reducing the pressure of the circulation circuit (15) as in the present invention, oxidation of the heat medium is prevented, and the heat medium is kept for a long time. It can be used, and even medium such as tempura oil that easily oxidizes can be used.
Further, since the pressure in the circulation circuit (15) is low, there is little risk of leakage, and the pressure difference between the inside of the heat transfer section (11) and the inside of the evaporation tank (1) is small, so that the heat transfer section ( The partition wall of 11) can be formed thin to improve the heat conduction efficiency.

Furthermore, since the pipe (28) is provided by utilizing the space (26) of the reservoir (14), it is not necessary to provide a special device in the circuit,
The circuit configuration does not become complicated.

(Effects of the Invention) As described above, according to the present invention, a pipe connected to the vacuum pump is provided in the space portion of the reservoir of the circulation circuit for the heat medium connected to the heat transfer portion of the rotor of the centrifugal evaporator. Since the whole system is maintained in a decompressed state, the heat medium can be prevented from being oxidized and the pressure difference between the inside and outside of the heat transfer section can be reduced to prevent leakage, and the partition wall of the heat transfer section can be made thin to conduct heat. There is an effect that efficiency can be improved, the structure is simple, and the manufacturing cost is low.

[Brief description of drawings]

 The drawings are diagrams showing an embodiment of the present invention. (1) …… Evaporation tank, (3) …… Rotor, (3a) …… Evaporation surface (11) …… Heat transfer part, (12) …… Heating device, (13) …… Pump (14) …… Reservoir, (15) ... Circulation circuit, (26) ... Space (27) ... Vacuum pump, (28) ... Piping

Claims (1)

[Claims] 1. A rotor having an outer surface formed on a liquid evaporation surface is rotatably provided inside an evaporation tank main body evacuated to a vacuum, and a heat transfer section, which is provided integrally with the rotor, for circulating a heat medium, A heat medium circulation circuit including a heater for heating the heat medium, a pump for circulating the heated heat medium through the heat transfer section, and a reservoir having a space for expansion and exchange of the heat medium. Centrifugal evaporation, characterized in that a pipe connected to a vacuum pump is connected to the space portion of the reservoir so as to maintain the entire circulation circuit in a depressurized state during heating and circulation of the heat medium. apparatus.