JP3226316B2 - Vapor compression evaporator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor compression type evaporator, and more particularly, to increase the number of revolutions of a vapor compressor at the start of a vapor compression type evaporator in accordance with the amount of vapor generated. The present invention relates to a vapor compression type evaporator as described above.

[0002]

2. Description of the Related Art FIG. 2 shows a vapor compression type evaporator (1) for concentrating a stock solution composed of an aqueous solution.

In FIG. 1, (2) is an evaporator for heating and evaporating the stock solution supplied to the first flow path (A), and (3) is a first flow path of the evaporator (2). This is a separator for performing gas-liquid separation of a stock solution containing an evaporation vapor discharged from (A), and separating the stock solution into an evaporation vapor and a concentrated solution.

[0004] (4) Preheats the stock solution supplied to the evaporator (2) and cools the evaporator vapor by the evaporative vapor discharged from the second flow path (B) of the evaporator (2). (5) is the second flow path (B) of the evaporator (2)
And a drain pot for separating evaporative vapor and vapor drain discharged from the vent condenser (4).

[0005] (6) and (7) are a vacuum device and a condensed water pump communicating with the drain pot (5).
As a result, the air generated in the drain pot (5) is released to the atmosphere, and the drain separated in the drain pot (5) is discharged to a predetermined location.

[0008] (8) is a circulation pump for returning the concentrated liquid separated in the separator (3) to the evaporator (2) again and sending it to a concentrated liquid tank (not shown).

(9) The evaporator (2) is used as a heat source for the evaporator (2) by suction-compressing the evaporative vapor generated in the separator (3).
A vapor compressor for supplying into the second flow path (B), and (10) a vapor compressor for evaporative vapor.
(9) Inlet vane for adjusting the intake volume to (9)
1) is an inlet vane operating device for operating the inlet vane (10).

[0008] (12) is a motor for driving the vapor compressor (9), (13) is a constant speed increase ratio of the gear type interposed between the motor (12) and the vapor compressor (9) Gearbox.

(14) A bypass valve interposed in a bypass passage (15) for returning the evaporation vapor discharged from the second passage (B) of the evaporator (2) into the separator (3). , (16) are bypass valve operating devices for operating the bypass valve (14).

In the above configuration, in order to concentrate the undiluted solution, first, the undiluted solution is supplied into the apparatus, and the bypass valve is provided.
After (14) is fully opened and the inlet vane (10) is reduced to a minimum, the condensate pump (7), the circulation pump (8) and the vapor compressor (9) are driven.

[0011] The undiluted solution flows from the vent condenser (4) to the evaporator.
When flowing into the separator (3) through the first flow path (A) of (2), the undiluted solution is again returned to the first flow path (A) of the evaporator (2) by the action of the circulation pump (8). Is repeated.

On the other hand, the air in the separator (3) is sucked by the vapor compressor (9),
The cycle (2) of returning from the second flow path (B) to the separator (3) through the bypass flow path (15) is repeated.

Then, while the above two cycles proceed simultaneously, evaporation starts from the undiluted solution in the separator (3), and after the evaporation vapor is suction-compressed by the vapor compressor (9), the evaporator ( The undiluted solution supplied to the second flow path (B) of (2) is heated by the heat of the compressed evaporative vapor, and flows through the first flow path (A) of the evaporator (2). When liquid separation is performed and concentration of the undiluted solution is performed, first, the bypass valve (14) is gradually tightened, and then the opening degree of the inlet vane (10) is gradually increased in accordance with the increase in evaporation vapor. Control to increase is performed, and the operation shifts to steady operation.

Thus, the vapor compression type evaporator (1)
Enters a steady operation, the stock solution supplied to the first flow path (A) of the evaporator (2) is heated, and an evaporative vapor and a concentrated liquid are formed in the first flow path (A).

The evaporative vapor and the concentrate are separated into gas and liquid in a separator (3), and the concentrate is sent to a concentrate tank, and a part of the concentrate is again supplied to the first flow path of the evaporator (2).
(A).

The evaporative vapor separated in the separator (3) is sucked and compressed by a vapor compressor (9), and then supplied to the second flow path (B) of the evaporator (2), where the evaporative vapor is evaporated. Used as a heat source.

The drain of the evaporation vapor discharged from the second flow path (B) of the evaporator (2) is supplied to a drain pot (5), and the remaining evaporation vapor is supplied to a vent condenser for preheating.
After being sent to (4), it flows into a drain pot (5), where gas-liquid separation is performed, the non-condensable gas is sent to a vacuum generator (6), and the drain is sent to a condensate pump (7). Is drained to a predetermined location.

[0018]

SUMMARY OF THE INVENTION A vapor compression evaporator
When (1) is configured as described above, until the vapor compression evaporator (1) enters a steady operation, the vapor compressor (9)
Because the rotation speed of the evaporator (2) cannot be changed, the second flow path (B) of the evaporator (2)
In addition to adjusting the opening of the bypass valve (14) interposed in the bypass flow path (15) provided between the separator and the separator (3), the inlet vane (10) provided immediately before the vapor compressor (9) By the vapor compressor (9)

It is necessary to control the suction amount of the vaporized vapor into the separator (3) so that the vaporized vapor is efficiently generated in the separator (3).

However, there is a problem that it is very difficult to reliably control the above two operations in accordance with the amount of evaporation vapor generated in the separator (3).

When the above control is performed, the bypass valve (14)
And a control mechanism for operating the inlet vane (10) and a bypass passage (15) are required.
There was also a problem that the structure of (1) became complicated.

Further, when the vapor compressor (9) is driven by the motor (12) through the speed-increasing gear (13), the motor (12) can be driven by an appropriate starting device, for example, a starting device employing a reactor starting method. There is also a problem that a large current flows at the time of the start of), so that it is necessary to enlarge the power receiving equipment.

[0023]

SUMMARY OF THE INVENTION An evaporative vapor generated in a separator disposed downstream of an evaporator is suction-compressed by a vapor compressor, and the suction-compressed evaporative vapor is used as a heat source of the evaporator. In the compression evaporator,

As a driving source of the vapor compressor, a motor composed of a high-speed rotation type induction motor is used.
An inverter is used as the motor rotation speed control means, and the rotation speed of the motor is increased in accordance with the increase in evaporation vapor generated in the separator when the vapor compression type evaporator is started.

[0025]

As described above, the number of revolutions of the vapor compressor itself is made variable by driving the vapor compressor by the motor controlled by the inverter, thereby simplifying the entire apparatus and facilitating the control at the time of starting. It is.

[0026]

FIG. 1 shows a vapor compression type evaporator (2) according to the present invention.
FIG. 2 is a block diagram showing the overall configuration of 1).

In the figure, (22) is an evaporator for heating and evaporating the stock solution supplied to the first flow path (A), and (23) is
This is a separator for performing gas-liquid separation of the undiluted solution containing the evaporation vapor discharged from the first flow path (A) of the evaporator (22) to separate it into an evaporation vapor and a concentrated liquid.

(24) Preheats the stock solution supplied to the evaporator (22) and cools the evaporative vapor by the evaporative vapor discharged from the second flow path (B) of the evaporator (22). Condenser (25) for the second flow path of the evaporator (22)
5 is a drain pot for separating drain from the evaporation vapor discharged from (B).

(26) and (27) are a vacuum device and a condensate pump connected to the drain pot (25).
According to 6), the air separated in the drain pot (25) is discharged to the atmosphere, and the drain separated in the drain pot (25) is discharged to a predetermined location by the condensed water pump (27). .

(28) is a circulation pump for returning the concentrate separated in the separator (23) to the evaporator (22) again and sending it to a concentrate tank (not shown). The members are the same as in the prior art.

(29) The evaporative vapor generated in the separator (23) is suction-compressed, and the evaporator is used as a heat source of the evaporator (22).
This is a vapor compressor for supplying to the second flow path (B) of (22).

Since the vapor compressor (29) is designed so that the rotation speed of the compressor itself can be varied by the action of a motor (30) and an inverter device (31), which will be described later, the conventional compressor (29) It is not necessary to dispose an inlet vane immediately before or to provide a bypass flow path or a control valve between the evaporator and the separator.

(30) The above-mentioned vapor compressor (29)
This motor (30) includes:
An induction motor capable of rotating at a high speed of 20,000 rpm or more is used.

(31) is an inverter device for controlling the rotation speed of the motor (30). In this embodiment, the inverter device (31) controls the rotation speed of the motor (30) to 3,3.
600rpm ~ 24,000rpm (0 ~ 400Hz)
To increase the speed.

In the above configuration, in order to concentrate the undiluted solution by the vapor compression evaporator (21) according to the present invention, the condensed water pump (27) and the circulation pump (28) are driven and the motor (30) is driven. ) Is started at a low speed by the action of the inverter device (31), so that the vapor compressor (29) driven by the motor (30) is started at a low speed.

The undiluted solution is supplied from the vent condenser (24) to the evaporator.
When the undiluted solution flows into the separator (23) through the first flow path (A) of (22), the undiluted solution is again returned to the first flow path (A) of the evaporator (22) by the action of the circulation pump (28). Is repeated.

On the other hand, since no evaporation vapor is generated in the separator (23) at this time, the vapor compressor (29) sucks and compresses the air in the separator (23), To the second flow path of the evaporator (22).
(B), and the circulating flow is heated and heated.

When evaporative vapor is gradually generated from the stock solution in the separator (23) while the above two cycles proceed simultaneously, the motor (30) is synchronized with the generation of the evaporative vapor. The rotation speed is increased to increase the rotation speed of the vapor compressor (29), and the suction compression of the evaporation vapor by the vapor compressor (29) is gradually increased.
To the second flow path (B).

Then, the stock solution flowing through the first flow path (A) of the evaporator (22) is heated by the heat of the evaporation vapor, gas-liquid separation is performed in the separator (23), and the stock solution is concentrated. As the amount of evaporative vapor generated in the separator (23) increases, the rotational speed of the motor (30) gradually increases with the increase of the evaporative vapor, and the rotational speed of the vapor compressor (29) increases. Increase and finally shift to steady operation.

Thus, the vapor compression type evaporator (21)
Enters a steady operation, the stock solution supplied to the first flow path (A) of the evaporator (22) is heated, and an evaporative vapor and a concentrated liquid are formed in the first flow path (A).

The evaporative vapor and the concentrate are separated into gas and liquid in a separator (23), the concentrate is sent to a concentrate tank, and a part of the concentrate is returned to the first flow path of the evaporator (22).
It is supplied to (A) and circulated.

The evaporative vapor separated in the separator (23) is sucked and compressed by the vapor compressor (29), and then supplied to the second flow path (B) of the evaporator (22), where the evaporative vapor is evaporated. Used as a heat source.

The drain of the evaporative vapor discharged from the second flow path (B) of the evaporator (22) is supplied to a drain pot (25), and the remaining evaporative vapor is supplied to a vent condenser (24) for preheating. After being sent, it flows into a drain pot (25), gas-liquid separation is performed, and the non-condensable gas is sent to a vacuum generator (26).
The drain is drained to a predetermined location by the condensed water pump (27).

In the above embodiment, the vapor compressor (29) at the start of the vapor compression type evaporator (21) is used.
The setting of the rate of increase of the number of rotations may be determined in advance by experiments or the like.

[0045]

As described above, in the vapor compression type evaporator according to the present invention, the vapor compressor for sucking and compressing the evaporative vapor generated in the separator and using it as the heat source of the evaporator is rotated by the inverter device. Is driven by the controlled motor, so that when the vapor compression evaporator is started, the rotation speed of the vapor compressor can be increased in accordance with an increase in the amount of evaporative vapor that starts to be generated in the separator.

Therefore, as in the conventional vapor compression type evaporator, an inlet vane is disposed immediately before the vapor compressor, and a bypass flow path having a bypass valve is provided between the second flow path of the evaporator and the separator. Since it is not necessary to control both the inlet vane and the bypass valve at the same time when starting the vapor compression evaporator, control at the start of the vapor compression evaporator becomes very easy,
The structure of the entire device is also very simple.

Further, if the motor for driving the vapor compressor is controlled by an inverter, the motor is rotated at a low speed at the time of starting the motor, so that a large current does not flow at the time of starting the motor. Can also be reduced in size, and as a result, the cost of the vapor compression evaporator can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of a vapor compression evaporator according to the present invention.

FIG. 2 is a block diagram showing a conventional example of a vapor compression evaporator.

[Explanation of symbols]

 Reference Signs List 21 vapor compression type evaporator 22 evaporator 23 separator 29 vapor compressor 30 motor 31 inverter device A first flow path B second flow path

Claims (1)

(57) [Claims] 1. A vapor compression type evaporator of a type in which evaporative vapor generated in a separator disposed downstream of an evaporator is suction-compressed by a vapor compressor, and the evaporative vapor thus suction-compressed is used as a heat source of the evaporator. In the above, a motor consisting of a high-speed rotation type induction motor is used as a drive source of the vapor compressor, and an inverter is used as a rotation speed control means of the motor. A vapor compression type evaporator characterized in that the number of rotations of a motor is increased in accordance with the amount of generated evaporative vapor.