JP2002254066A - Vacuum evaporation type desalination plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum evaporation type desalination plant equipped with an inexpensive and reliable noncondensing gas discharge means to discharge noncondensing gas inside equipment without using a vacuum pump. SOLUTION: In a vacuum evaporation type desalination plant where raw water is heated under reduced pressure directly or indirectly by the heat source, an evaporative distiller 10 is equipped to generate and condense a steam to produce freshwater and a freshwater drain pump 30 is equipped to discharge the produced freshwater, a condensation extraction means (condensation extraction pipe 17 and ejector 23, etc.), to collect the noncondensing gas inside the system and a condensation extraction tank 16 to store the noncondensing gas collected by the condensation extraction means under subatmospheric pressure are installed. The pressurization up to or over atmospheric pressure inside the condensation extraction tank 16 can be performed by the freshwater drain pump 30 and when the noncondensing gas inside the condensation extraction tank 16 is discharged, the inside of the condensation extraction tank 16 is pressurized by the freshwater drain pump 30 and the noncondensing gas is discharged outside the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum evaporation type desalination apparatus for producing raw water by heating raw water under reduced pressure and condensing generated steam.

[0002]

2. Description of the Related Art In a vacuum evaporation type desalination apparatus, particularly in a vacuum evaporation type desalination apparatus which performs desalination using solar heat or waste heat, the inside of the apparatus has been evacuated and the non-condensation contained in raw water has been used. As means for discharging (bleeding) non-condensable gas such as non-condensable gas or air leaking into the apparatus, a vacuum pump is usually used. However, the method using a vacuum pump for discharging non-condensable gas has the following problems.

The inside of a vacuum evaporation type desalination apparatus has a relatively high water vapor partial pressure, that is, a ratio of water vapor, and cannot be used with a normal vacuum pump or the load is large. Further, water easily accumulates in the vacuum pump, and it is necessary to frequently perform operations such as drainage.

The power for driving the vacuum pump includes:
In an evaporative desalination apparatus that normally requires electric power and uses heat as a direct driving force for desalination, the load of a vacuum pump is large among auxiliary equipment.

[0005] Further, the vacuum pump requires regular maintenance and inspection and replacement such as disassembly cleaning and oil replacement.

[0006] The above-mentioned problems become serious problems especially when the desalination apparatus is to be operated unattended for a long time. Further, in a desalination apparatus using solar heat or the like as a driving force, the power generated by a solar cell or the like can cover the power required by the apparatus, and thus reducing the power consumed by the apparatus is a major issue.

As a method of performing bleeding without using a vacuum pump, discharge by an ejector device can be considered. But,
The pressure inside the vacuum evaporation type desalination unit is 1/1 of atmospheric pressure
When the non-condensable gas is exhausted by the ejector device from the internal pressure of the device to the atmospheric pressure, the following problem occurs.

In the case of a liquid ejector, the power for driving the fluid, the flow rate of the fluid for driving, and the like become large.

[0009] The steam ejector requires high-pressure steam,
Handling of exhaust gas and water supply are problematic.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made inexpensive and highly reliable non-condensable gas without using a vacuum pump for discharging the non-condensable gas in the apparatus. It is an object of the present invention to provide a vacuum evaporation type desalination apparatus having a discharge means.

[0011]

Means for Solving the Problems To solve the above problems, the invention according to claim 1 is to heat raw water under reduced pressure with heat supplied directly or indirectly from a heat source to generate steam and generate the steam. Equipped with an evaporative still to produce fresh water by condensing
In a vacuum evaporation type desalination apparatus provided with at least one drainage means for discharging the produced fresh water or concentrated raw water or raw water to the outside of the apparatus, a bleeding means for collecting non-condensable gas in the apparatus, and a bleeding means Along with providing an bleeding tank for storing the collected non-condensable gas at or below the atmospheric pressure, and providing a pressurizing means for pressurizing the bleeding tank to at least the atmospheric pressure or about the atmospheric pressure using a drainage means, When discharging the non-condensable gas, the inside of the bleeding tank is pressurized by pressurizing means,
The non-condensable gas is discharged outside the apparatus.

As described above, the non-condensable gas collected by the bleeding means is stored in the bleed tank which stores the gas at a pressure lower than the atmospheric pressure. The power of the bleed means can be small. Further, since the drainage means provided in the vacuum evaporation type desalination apparatus is used as the pressurizing means for pressurizing the inside of the bleeding tank and discharging the non-condensable gas to the outside, the non-condensable gas stored in the bleeding tank is used. There is no need to provide any special means for discharging the condensable gas.

According to a second aspect of the present invention, in the desalination apparatus according to the first aspect, the bleeding means for collecting the non-condensable gas in the apparatus is an ejector driven by a fluid.

As described above, even if an ejector driven by a fluid is used for the bleeding means for collecting non-condensable gas in the apparatus,
Since the non-condensable gas extracted by the ejector is discharged into the extraction tank whose inside is equal to or lower than the atmospheric pressure, the flow rate and power of the fluid for driving the ejector can be reduced.

[0015] The invention described in claim 3 is the first or second invention.
The non-condensable gas in the high temperature part of the evaporative distillation apparatus is directly guided to the extraction tank through the extraction pipe.

As described above, the non-condensable gas in the high-temperature portion of the evaporator is directly guided to the extraction tank by the extraction pipe, so that the power of the extraction means is reduced accordingly.

The invention described in claim 4 is the first to third aspects of the present invention.
In the desalination apparatus according to any one of the above, the bleeding tank is provided in the drainage path of the drainage means as a part of the drainage path, and discharge of the non-condensable gas is performed by drainage. Is performed on the same route.

As described above, the bleeding tank is provided in the middle of the drainage path as a part of the drainage path, and the discharge of the noncondensable gas is performed through the same path as the drainage. Therefore, it is not necessary to provide a separate discharge path, and the configuration of the discharge exhaust gas path is simplified.

The invention described in claim 5 is the invention according to claims 2 to 4
In the desalination apparatus according to any one of the above, the ejector driving means for driving the ejector and / or the pressurizing means for pressurizing the bleeding tank is a freshwater drainage pump for discharging freshwater. .

As described above, the ejector driving means and / or the pressurizing means for pressurizing the bleeding tank is provided with the fresh water drainage pump for discharging fresh water, so that the ejector driving means and / or
Or, it is not necessary to separately provide a pressurizing means, and since fresh water is used, impurities are less likely to cause a malfunction,
Even in the case of backflow, contamination in the apparatus can be minimized.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention. In FIG. 1, 1
Reference numeral 0 denotes an evaporative evaporator that heats raw water under reduced pressure, generates steam, and condenses the steam to produce fresh water (distilled water). The evaporative evaporator 10 is supplied directly or indirectly from a heat source. The raw water is heated by heat to generate steam.

Further, reference numeral 11 denotes a condenser, and 12 denotes a fresh water tank. Fresh water (distilled water) generated and condensed in the evaporator 10 flows into the fresh water tank through a fresh water passage 13. The steam not condensed in the evaporative distillation apparatus 10 flows into the condenser 11 through the vapor flow path 14 and is condensed.
The fresh water is condensed at 1 and flows into the fresh water tank 12 through the fresh water flow path 15.

Reference numeral 16 denotes a bleeding tank for storing a noncondensable gas at a pressure lower than the atmospheric pressure during operation of the vacuum evaporation type desalination apparatus. The high temperature section is connected via an extraction pipe 17 and an extraction control valve 18. The non-condensable gas in the condenser 11 and the non-condensable gas in the fresh water tank 12 are supplied to the non-condensable gas passage 19, the bleed control valve 20, and the non-condensable gas passage 2, respectively.
The air is extracted by the ejector 23 through the air extraction control valve 22 and the air extraction control valve 22, and is discharged into the air extraction tank 16.

Reference numeral 24 denotes an ejector drive pump for driving the ejector 23; 25, an exhaust valve for exhausting non-condensable gas collected in the bleed tank 16; 26, a pressure for detecting the pressure in the bleed tank 16; 27, bleed tank 1
Reference numeral 28 denotes a pressurizing valve for pressurizing the inside of the bleeding tank 16. A freshwater drainage channel 29 is connected to the freshwater tank 12, and a freshwater drainage pump 30 and a drainage valve 31 are connected to the freshwater drainage channel 29.

The non-condensable gas in the high-temperature section (high-pressure section) of the evaporator 10 is directly guided to the bleed tank 16 via the bleed pipe 17 and the bleed control valve 18. Further, the low-temperature portion of the evaporative evaporator 10 communicating with the fresh water tank 12 and the non-condensable gas of the condenser 11 are collected by the ejector 23 and discharged into the extraction tank 16. In addition, ejector 2
Numeral 3 is driven by supplying fresh water from the bleed tank 16 with an ejector drive pump 24.

The non-condensable gas in the apparatus is collected in the bleed tank 16 as described above, and when it is determined that a certain amount of the non-condensable gas has accumulated in the bleed tank 16 (when the internal pressure of the bleed tank has exceeded a certain level). Occasionally, at regular intervals, the evaporative evaporator 1
When the supply amount of raw water supplied to the water tank 0 reaches a certain level or more, or when a certain amount of fresh water accumulates in the fresh water tank 12), the drainage pump 30 is operated and the pressurizing valve 28 is opened. The inside of the bleeding tank 16 is pressurized, and the non-condensable gas collected in the bleeding tank 16 is mixed with the fresh water in the bleeding tank 16 and discharged through the exhaust valve 25 and the freshwater drainage passage 29 ′ indicated by a dotted line. Is done.

Since the bleeding tank 16 is under reduced pressure during the desalination operation of the vacuum evaporation type desalination apparatus as described above, the ejector is used to extract noncondensable gas in the condenser 11 and the fresh water tank 12 to the ejector. A small amount of fluid is required (an ejector with a small capacity is sufficient). Further, since the discharge pressure of the fresh water drainage pump 30 is used for pressurizing the bleeding tank 16, the bleeding tank 1
Since the non-condensable gas collected in 6 is discharged, the number of newly added devices is small.

In the above-mentioned vacuum evaporation type desalination apparatus, the pressurizing valve 28 is provided to separate the drainage of fresh water and the discharge of non-condensable gas, but the drain valve 31 for discharging fresh water and the pressurizing valve 28 are provided. May be combined as a three-way valve, and may be replaced with a liquid ring, or may be omitted. Also, in this case, by detecting a drop in the liquid level of the bleeding tank 16 with the water level gauge 27,
It can be known that non-condensable gas is accumulated.

In order to discharge only the non-condensable gas in the bleeding tank 16, the inside of the bleeding tank 16 is pressurized and the liquid level rises above the bleeding tank 16 while detecting the rising liquid level in the bleeding tank 16. When it reaches, it is preferable to stop the discharge or, as shown in FIG. 2, provide an air lock tank 33 to form an air lock 33a and allow fresh water coming out of the bleed tank 16 to be sucked again. In FIG. 2, reference numeral 34 denotes an exhaust valve. In this case, the level switch 3 of the airlock tank 33
After exhaling non-condensable gas and fresh water until 5 works,
After the freshwater drainage pump 30 is stopped and the level switch 35 returns, the exhaust valve 34 is closed.

The non-condensable gas mixed with fresh water may flow into the fresh water drain 29 (fresh water drain 29 'shown by a dotted line). In this case, air is mixed into the freshwater drainage channel 29, but if necessary, a gas-liquid separator may be provided outside.

If the freshwater drainage pump 30 is a non-backflowable pump (such as a gear pump or a diaphragm pump), a bypass valve 32 is mounted in parallel with the freshwater drainage pump 30.

As the liquid to be fed into the bleeding tank 16 and the driving fluid for the ejector 23 and the like, concentrated raw water or raw water may be used instead of fresh water. Even in this case, fresh water is preferable to minimize troubles such as contamination in the apparatus.) There is no particular limitation on the locations of the bleeding points of the evaporative distillation apparatus 10 and the condenser 11. For example, the heat collection system of the evaporative distillation apparatus 10 may be used.

To detect that the pressure in the bleed tank 16 has risen to atmospheric pressure, the pressure gauge 26
Although it is preferable to detect the internal pressure, it may be determined that the atmospheric pressure has been reached when a certain time has elapsed after the operation of the freshwater drainage pump 30. If there is only one bleeding tank 16,
Since the non-condensable gas cannot be extracted during the exhaust, a method of alternately using two systems by providing two systems is also conceivable.

FIG. 3 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention. In the present vacuum evaporation type desalination apparatus, the non-condensable gas collected in the condenser 11 by the steam flow in the cycle (the non-condensable gas in the fresh water tank 12 also passes through the non-condensable gas flow path 36 and the condenser 11 Collected in)
Into the bleeding tank 16 and the non-condensable gas flow path 19 and the check valve 3
7 and are collected and guided by the ejector 23. The ejector 23 is connected to the freshwater tank 12 by an ejector drive pump 24.
Driven by freshwater inside. The freshwater that has driven the ejector 23 flows back through the freshwater drainage pump 30 and the freshwater tank 1
Return to 2. Reference numeral 38 denotes a check valve disposed between the ejector 23 and the ejector drive pump 24.

In this vacuum evaporation type desalination apparatus, the pressurizing means for pressurizing the bleeding tank 16 is a fresh water drainage pump 30,
In addition, since the bleeding tank 16 is configured as a part of the freshwater drainage channel 29, the noncondensable gas collected in the bleeding tank 16 is simultaneously discharged when the freshwater is discharged from the apparatus.

An operation method of the vacuum evaporation type desalination apparatus will be described below. When collecting non-condensable gas in the bleeding tank 16, the ejector drive pump 24 is operated. Thereby, the non-condensable gas in the device is collected in the bleeding tank 16. The liquid (fresh water) that has driven the ejector 23 flows back through the fresh water drain pump 30 and returns to the fresh water tank 12 as described above.

As the non-condensable gas collects in the bleeding tank 16, the pressure in the bleeding tank 16 rises and the liquid level drops, and when the water level gauge 27 operates, the fresh water drainage pump 30 is operated. The inside of the bleeding tank 16 is pressurized, the discharge valve 39 is opened, and the non-condensable gas is discharged together with the fresh water. in this case,
The discharge valve does not have to be opened until the internal pressure rises. Also,
A check valve may be used instead of the discharge valve.

As the fresh water is discharged, the liquid level in the fresh water tank 12 drops. When the water level gauge 40 detects that the liquid level in the fresh water tank 12 has dropped to a specified position, the discharge valve 3
9 is closed, and the freshwater drainage pump 30 is stopped. At this time, the freshwater drainage channel 29 from the freshwater tank 12 to the bleeding tank 16
And so on, the fresh water amount is always constant, so that the fresh water corresponding to the fresh water amount stored in the fresh water tank 12 from the previous discharge is discharged outside the apparatus.

Between the bleeding tank 16 and the fresh water drainage pump 30, an adjusting valve for adjusting the return amount of the liquid (fresh water) or a liquid seal may be provided. If the freshwater drainage pump 30 is a pump (diaphragm pump, gear pump, or the like) that does not easily flow backward, a bypass valve may be provided. Since a small amount of air will be mixed into the wastewater, a gas-liquid separator may be provided outside the apparatus if necessary. Or ejector drive pump 24
And the freshwater drainage pump 30 may also be used.

FIG. 4 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention. In the present vacuum evaporative desalination apparatus, the non-condensable gas in the high-temperature part (high-pressure part) of the evaporative evaporator 10 is led directly to the bleed tank 16 through the bleed pipe 17, The condensable gas is collected by the ejector 23 through the non-condensable gas channel 19 and the check valve 37 and is discharged into the bleeding tank 16. Ejector 23
The fresh water in the fresh water tank 12 is used as the drive fluid for the, and is driven by the fresh water drainage pump 30. A three-way valve 43 is provided in the freshwater drainage channel 29, and a freshwater return flow path 44 is provided between one end of the three-way valve 43 and the freshwater tank 12.

The bleeding tank 16 is provided with a high water level gauge 41 for detecting a high water level and a low water level gauge 42 for detecting a low water level. When collecting non-condensable gas in the bleeding tank 16, 3
The freshwater drainage path 29 to the bleeding tank 16 is closed by the direction valve 43, freshwater is sent to the ejector 23 by the freshwater drainage pump 30, and the ejector 23 is driven. As a result, the non-condensable gas in the device is bled by the ejector 23,
It is discharged into. The liquid (fresh water) that has driven the ejector 23 passes through the three-way valve 43 and the fresh water return flow path 44 and the fresh water tank 12
Return to

As the non-condensable gas collects in the bleeding tank 16, the pressure in the bleeding tank 16 rises and the liquid level drops, and when the low water level gauge 42 operates, the three-way valve 43 operates the fresh water return flow path. 44 is closed, and the liquid discharged from the freshwater drainage pump 30 is sent to the bleeding tank 16. By opening the discharge valve 39,
The non-condensable gas in the bleed tank 16 is exhausted. When the liquid level rises and the high water level gauge 41 operates, the discharge valve 39 is closed, and
The fresh water return flow path 44 is closed by the direction valve 43. Thereby, the non-condensable gas in the apparatus is collected in the bleeding tank 16 by the same operation as described above.

To discharge fresh water from the fresh water tank 12, the three-way valve 43 closes the fresh water return flow path 44, and simultaneously operates the fresh water drain pump 30 and opens the discharge valve 39, thereby opening the fresh air tank. The 16 non-condensable gases and fresh water are discharged. As the fresh water is discharged, the liquid level in the fresh water tank 12 drops. When the water level gauge 40 detects that the liquid level in the freshwater tank 12 has dropped to the prescribed position, the discharge valve 39 is closed, and the three-way valve 43 closes the freshwater drainage passage 29 to the bleeding tank 16.

In the above-mentioned vacuum evaporation type desalination apparatus, the valves and the pumps of the respective components may be replaced by alternative means. For example, replacing a two-way valve with a check valve,
The same operation as the one-way valve may be configured by combining the two-way valve.

FIG. 5 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention. In this vacuum evaporative desalination apparatus, the low-temperature portion of the evaporative still 10 and the non-condensable gas of the condenser 11 are collected by the ejector 23 through the check valve 37 and discharged to the bleed tank 16. The non-condensable gas such as the low-temperature portion (including the fresh water tank 12 and the like) of the other evaporative distillation apparatus 10 is generated by the vapor flow of the evaporative concentration cycle
All are transported to the condenser 11. If necessary, the non-condensable gas in the high-temperature section (high-pressure section) of the evaporator 10 can be sent directly to the bleed tank 16 through a bleed pipe. 46 is a high water level meter for detecting the high water level of the fresh water tank 12, and 47 is a low water level meter for detecting the low water level.

As the driving liquid and the driving source of the ejector 23, the discharge liquid (fresh water) of the fresh water drainage pump 30 is used. As the pressurizing means here, the control valve for returning the driving liquid of the ejector 23, that is, the discharge control valve 45 is closed to increase the internal pressure of the bleeding tank 16, and the non-condensable gas and the fresh liquid as the driving liquid At the same time, it can be discharged out of the apparatus through the discharge check valve 48.

The operation control of the vacuum evaporation type desalination apparatus having the above configuration may be performed, for example, as follows. The water level gauge 27
When the lowering of the liquid level in the bleeding tank 16 is detected, the discharge control valve 45 is closed. At this time, the inside of the bleed tank 16 is pressurized by fresh water sent through the ejector 23.
After the switching, when the pressure in the bleeding tank 16 becomes equal to or higher than the atmospheric pressure, the non-condensable gas and the fresh water are discharged through the discharge check valve 48.

At this time, if a flow restricting means (orifice or the like) is provided in the return pipe 49 of the fresh water, the pressure in the bleeding tank 16 during bleeding can be increased and the volume of the bleeding tank 16 can be reduced. In this case, the capacity of the flow restricting means is derived from the exhaust capacity of the ejector 23 and the characteristics of the pump. At the maximum pressure during the bleeding of the bleeding tank 16, the capacity should be such that the corresponding flow rate can be returned.

Also, for example, the pressure in the bleeding tank 16 is measured by the pressure gauge 26 or the like, and the opening of the discharge control valve 45 is controlled in accordance with the measured pressure. Can also be controlled appropriately. Specifically, for example, the operation (control) may be performed as follows. For example, the opening degree of the discharge control valve 45 is adjusted so that the pressure in the bleeding tank 16 becomes a set value in accordance with the exhaust capacity of the ejector 23 (opens when the pressure increases, closes when the pressure decreases). . Here, when a drop in the liquid level is detected by the water level meter at the set pressure, it is determined that the limit amount of the non-condensable gas has been accumulated, the discharge control valve 45 is fully closed, and the non-condensable gas and fresh water are discharged. I do. Thereby, the volume of the bleeding tank can be minimized while the drive flow rate of the ejector is minimized.

By constructing the vacuum evaporation type desalination apparatus as shown in FIG. 5, the number of devices constituting the apparatus can be reduced as a whole and the cost of the apparatus can be reduced.

Also, in FIGS.
2 and the bleeding tank 16 and the like are separately provided, but for production and design, the fresh water tank 12, the bleeding tank 16, and a raw water tank (not shown) are configured as an integrated device with the evaporative distillation unit 10 and the condenser 11. Is also good.

Further, the preferable characteristics of the freshwater drainage pump 30 are that a large flow required for driving the ejector 23 is operated even when the head is low during bleeding. The one that can drive for is good. For example, a centrifugal vortex pump or the like is preferable.

The raw water used in the above embodiment is seawater,
Refers to water containing a lot of salt and impurities such as groundwater.

[0054]

As described above, according to each claim, the following excellent effects can be obtained.

According to the first aspect of the present invention, the non-condensable gas collected by the bleeding means is stored in the bleeding tank at a pressure lower than the atmospheric pressure. The power of the bleeding means for bleeding gas is small. Further, since the drainage means provided in the vacuum evaporation type desalination apparatus is used as the pressurizing means for pressurizing the inside of the bleeding tank and discharging the non-condensable gas to the outside, the non-condensable gas stored in the bleeding tank is used. There is no need to provide any special means for discharging the condensable gas.

According to the second aspect of the present invention, even if an ejector is used as the bleeding means for collecting the noncondensable gas in the apparatus, the inside of the noncondensable gas extracted by the ejector is lower than the atmospheric pressure. Since the fluid is discharged into the bleeding tank, the flow rate and power of the fluid for driving the ejector can be reduced.

According to the third aspect of the present invention, since the non-condensable gas in the high temperature portion of the evaporator is directly guided to the bleed tank by the bleed pipe, the power of the bleed means is reduced accordingly.

According to the fourth aspect of the present invention, the bleeding tank is provided in the middle of the drainage path as a part of the drainage path,
Since the discharge of the non-condensable gas is performed in the same path as the waste liquid, the configuration of the path for the discharged exhaust gas is simplified.

According to the fifth aspect of the present invention, the ejector driving means and / or the pressurizing means are provided by using a fresh water drainage pump for discharging fresh water for the ejector driving means and / or the pressurizing means of the bleeding tank. There is no need to provide a separate device, and since fresh water is used, the amount of impurities is small, which is unlikely to cause malfunction, and contamination in the apparatus can be minimized even in the case of backflow.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration example of a means for discharging a non-condensable gas from a bleeding tank of the vacuum evaporation type desalination apparatus according to the present invention.

FIG. 3 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention.

FIG. 4 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention.

FIG. 5 is a diagram showing a configuration example of a vacuum evaporation type desalination apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Evaporation distillation apparatus 11 Condenser 12 Fresh water tank 13 Fresh water flow path 14 Steam flow path 15 Fresh water flow path 16 Extraction tank 17 Extraction pipe 18 Extraction control valve 19 Non-condensable gas flow path 20 Extraction control valve 21 Non-condensable gas flow path Reference Signs List 22 Extraction control valve 23 Ejector 24 Ejector drive pump 25 Exhaust valve 26 Pressure gauge 27 Water level gauge 28 Pressurization valve 29 Freshwater drainage channel 29 'Freshwater drainage channel 30 Freshwater drainage pump 31 Drainage valve 32 Bypass valve 33 Air lock tank 34 Exhaust valve 35 level switch 36 non-condensable gas flow path 37 check valve 38 check valve 39 discharge valve 40 water level gauge 41 high water level meter 42 low water level meter 43 three way valve 44 fresh water return flow path 45 discharge control valve 46 high water level meter 47 Low water level gauge 48 Discharge check valve 49 Fresh water return piping

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor: Kiichi Irie 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation 4D034 BA03 CA12 4D076 AA22 BA01 CD21 CD22 HA01 JA03 JA04

Claims (5)

[Claims] 1. An evaporative distillation apparatus for heating raw water under reduced pressure with heat supplied directly or indirectly from a heat source to generate steam and condensing the steam to produce fresh water. Alternatively, in a vacuum evaporative desalination apparatus provided with one or more drainage means for discharging concentrated raw water or raw water out of the apparatus, a bleed means for collecting non-condensable gas in the apparatus, and a non-condensate collected by the bleed means And a pressurizing means for pressurizing the bleeding tank to above or above atmospheric pressure using the drainage means, and providing a non-condensable gas in the bleeding tank. When discharging the gas, the pressurizing means pressurizes the inside of the bleeding tank, and discharges the non-condensable gas to the outside of the apparatus. 2. The desalination apparatus according to claim 1, wherein the extraction means for collecting non-condensable gas in the apparatus is an ejector driven by a fluid. 3. The desalination apparatus according to claim 1, wherein the non-condensable gas in a high-temperature portion of the evaporative still is directly guided to the extraction tank through an extraction pipe. Vacuum evaporation desalination equipment. 4. The desalination apparatus according to claim 1, wherein the bleeding tank is provided in a middle of a drainage path of the drainage unit.
A vacuum evaporation type desalination apparatus provided as a part of the drainage path and discharging the non-condensable gas through the same path as the drainage. 5. The desalination apparatus according to claim 2, wherein the ejector driving means for driving the ejector and / or the pressurizing means for pressurizing the bleeding tank discharge fresh water. A vacuum evaporation type desalination apparatus characterized by being a drainage pump.