JP3237532B2 - Control method of deaerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Field of the Invention The present invention relates to a method of controlling a deaerator for removing dissolved gas from the liquid.

[0002]

2. Description of the Related Art As is well known, deaerators for removing dissolved gases from liquids are used in various fields in order to remove dissolved gases which are a main factor of oxidation. For example, to prevent corrosion of cooling / heating devices such as steam boilers, hot water boilers, and cooling towers and their water supply piping, and to prevent corrosion of piping such as water supply, hot water supply, and air conditioning equipment in buildings such as buildings and condominiums (so-called red water). ), And for preventing oxidation and corrosion of objects to be washed and products in a washing process of electronic parts, machine parts, and the like.

[0003] As such a deaerator, a so-called membrane deaerator using a gas permeable membrane or a gas separation membrane is frequently used because of its compactness and easy handling.
An example of this type of membrane deaerator will be described with reference to FIG. In the deaerator illustrated in FIG. 4, a gas permeable membrane (not shown) is formed into a tubular, hollow fiber, pleated, spiral (spooled) shape, or the like, and stored in an appropriate container in this state. Is used as a so-called membrane module 31, which is a single component. The inside of the membrane module 31 is partitioned into a liquid phase side and a gas phase side,
On the liquid phase side, a raw water supply line 32 provided with a water supply pump (not shown) for supplying raw water (including well water, tap water, various industrial waters, other liquid products, etc.) for deaeration and a deaeration treatment A treated water supply line 34 for supplying a treated water tank 33 for storing the treated water is connected. Further, a vacuum suction line 35 for vacuum suction in the compartment is connected to the gas phase side. And the membrane module 31
In the distribution process of the raw water in the inner, by vacuum suction through the gas permeable membrane, the dissolved gas in the raw water was aspirated and the treated water which has been degassed from the treated water supply line 34 to the treated water tank 33 Supply.

[0004] As shown in FIG.
5 is connected to a water ring vacuum pump 36 as vacuum suction means. Since the water seal type vacuum pump 36 discharges the water sealing together with the exhaust, it is necessary to refill the water sealing, and the amount of the water sealing becomes large. Accordingly, the sealing water tank 38 for storing the sealing water in the sealing water supply line 37 branching from the raw water supply line 32 is provided to connect the exhaust line 39 of the water ring vacuum pump 36 in the water seal tank 38, the seal water is circulated between the water ring vacuum pump 36 and the water seal tank 38, thereby achieving the recycling of sealing water.

An upper limit water level detector 40 (for example , a ball tap type) is provided in the treated water tank 33. When the treated water level reaches the upper limit water level, the supply of treated water into the treated water tank 33 is performed. To stop. On the other hand, the flow switch 41 is provided in the treatment <br/> management water supply line 34
And it has the signal line 4 a detection signal of the flow switch 41
2 to the controller 43. Further, the controller 4
3 and connects the water ring vacuum pump 36 by a signal line 42, the detection signal of the flow switch 41 has a configuration for turning on and off the said water ring vacuum pump 36.

With the above configuration, the upper limit water level detecting device 4
0, the supply of the treated water into the treated water tank 33 is stopped and the supply of the treated water is stopped.
Is turned on and off . That is, when the water ring vacuum pump 36 is in operation, the membrane module 31 is configured to always supply a constant amount of treated water into the treated water tank 33.

By the way, in the above conventional degasser, a process water accumulated in the treated water tank 33 is supplied to the use point by the load requirements, supplementation treated water
Supplied from the raw water supply line 32 to the raw water in a predetermined amount into the membrane module 31, and supplies the deaerated water of a predetermined concentration of dissolved oxygen to the treated water tank 33. However, in the above degassing apparatus, as shown in FIG. 2, if the amount of treated water to passed through the membrane module 31 is constant, as the temperature of raw water supplied is low, high dissolved oxygen concentration in the treated water There is a characteristic that becomes. If the raw water temperature is constant , the dissolved oxygen concentration becomes lower as the amount of treated water is smaller.
Therefore, the dissolved oxygen concentration is low in summer when the water temperature is high, and increases in winter when the water temperature is low. Therefore, especially in a cold region, the variation in the dissolved oxygen concentration increases in summer and winter.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling a deaerator which can reduce the concentration of dissolved oxygen in treated water in view of the above problems.

[0009]

Means for Solving the Problems The present invention has been made to solve the above problems, and the invention according to claim 1 has a raw water supply line for supplying raw water and a raw water supply line for supplying raw water. A deaeration unit for deaeration processing, a treated water tank for storing deaerated treated water, a level sensor for detecting a water level in the treated water tank is provided, and an upper limit water level in the treated water tank is provided. An upper limit water level detecting means for detecting the level sensor, and a flow control valve for controlling a supply amount based on a signal from the level sensor in the raw water supply line, the method for controlling a deaerator comprising: At this time, the flow control valve is fully opened, and the supply amount of raw water to be supplied to the deaeration means is controlled based on the operation of the upper limit water level detection means.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described. The present invention relates to a raw water supply line, a membrane module as a deaerator for deaerated the supplied raw water, and a deaeration process. This is realized in a deaerator including a treated water tank for storing treated treated water, a treated water supply line for supplying treated water to the treated water tank, and a water-sealed vacuum pump for vacuum suction of the inside of the membrane module. Is done. That is, the supply amount of raw water to be supplied to the membrane module is proportionally controlled based on the water level that changes when the treated water in the treated water tank is supplied to the load side. Further, the configuration of the control device embodying the present invention is such that a level sensor (a water level is detected using a pressure gauge) for detecting a water level is provided in the treated water tank, and an upper limit water level in the treated water tank is detected. And an upper limit water level detecting means. A flow control valve is provided in the raw water supply line, and the flow control valve and the level sensor are connected to a controller via signal lines, respectively.

According to the control device having the above configuration, the level sensor detects a water level in the treated water tank, and outputs a detection signal to the controller. Before receiving this detection signal
Serial controller, when detecting the water level is equal to or greater than the preset water level, so that the supply amount preset raw water supply amount to be supplied to the membrane module on the basis of the detected water level (less than the standard raw water supply amount), the A flow control valve is adjusted to supply a predetermined amount of raw water to the membrane module in proportion. Therefore, the treated water amount of the membrane module is smaller than the standard amount, and the dissolved oxygen concentration in the treated water can be lower than the standard value.

[0012] As described above, as to detect the water level of the treated water tank that varies the supply amount of the treatment water to be supplied to the load side, to adjust the supply amount of the raw water supplied to the membrane module proportionally since the, for example, if the process water is supplied to the load side is less than the standard amount of water treated in the membrane module, does not water level much reduction in the treated water tank, raw water supply amount is reduced is supplied to the membrane module, The dissolved oxygen concentration in the treated water can be reduced.
Therefore, as in the conventional, the water level of the treated water tank
And on-off control, as compared with when a constant supply amount of raw water supplied to the membrane module, it is possible to reduce the dissolved oxygen concentration in the treated water, the effect is large especially in cold climates.

According to the present invention, when the level sensor is abnormal, the flow rate control valve is fully opened and the supply amount is controlled based on the operation of the upper limit water level detecting means. Supply will not stop.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing a basic configuration of a deaerator suitable for carrying out the present invention.

The deaerator shown in FIG . 1 basically supplies raw water (including well water, tap water, various industrial waters, other liquid products, etc.) for deaeration by a water supply pump (not shown). A raw water supply line 1 to be supplied, a membrane module 2 as a deaeration means for deaeration of the supplied raw water,
A treated water tank 3 for storing deaerated treated water, a treated water supply line 4 for supplying treated water to the treated water tank 3, and a water ring vacuum pump 6 for vacuum-suctioning the inside of the membrane module 2. It consists of. The membrane module 2
A gas permeable hollow fiber membrane (not shown) are configured as those contained in the container, the interior of the membrane module 2 is divided into a liquid phase side and the gas phase side by a gas permeable membrane. The membrane module 2, its liquid phase side is connected the raw water supply line 1 and its the gas phase side is connected with the water ring vacuum pump 6 through the vacuum suction line 5. Accordingly, in the distribution process of the raw water in the membrane module 2, the water seal type vacuum attracting the membrane module 2 through the gas permeable membrane by the vacuum pump 6, the dissolved gas in the raw water was removed by aspiration, leaving The treated water is supplied to the treated water tank 3 via the treated water supply line 4.

[0016] Now, the control apparatus of this invention, provided with a level sensor 7 for detecting the water level of the treated water tank 3, the upper limit water level detector as a detecting means for detecting an upper limit level of the treated water tank 3 11 To provide
It is constituted by. A flow control valve 8 is provided in the raw water supply line 1, and the flow control valve 8 and the level sensor 7 are connected to a controller 10 via signal lines 9, respectively. The level sensor 7 is configured to detect a water level using a pressure gauge. The level sensor 7 is installed near the bottom of the treated water tank 3 to detect a treated water level in the treated water tank 3. A signal is output to the controller 10. The controller 1 receiving the detection signal
0, as shown in FIG. 3, based on the raw water supply amount for a given water level is set in advance, as the raw water supply amount to be supplied to the membrane module 2, a predetermined raw water supply, the flow rate control valve 8 is proportionally controlled. As shown in FIG. 3, this control method is control performed when the water level of the treated water tank 3 is equal to or higher than a set water level L (intermediate water level (50%)).

The upper limit water level detecting device 11 is provided with a pilot valve 12 having a ball tap for detecting a preset upper limit water level H in the treated water tank 3, and a constant water level valve 13 linked to the pilot valve 12. Is provided in the treated water supply line 4.

Upper limit water level detecting device 11 in this embodiment
For, To further illustrate, the upper limit water level detector 40 of the conventional ball tap method, to the treatment water tank 3
During the inflow of the treated water, there was a risk that water droplets were generated on the water surface and oxygen and the like were redissolved. Therefore, the upper limit water level detection device 11 of this embodiment is provided to prevent re-dissolution.
The front end of the treated water supply line 4 is extended to near the bottom of the treated water tank 3.

In the water-sealed vacuum pump 6 shown in FIG. 1, since the water is discharged together with the evacuation, it is necessary to replenish the water and the amount of the water to be used becomes large. For this reason,
Sealed water supply line 14 branched from the raw water supply line 1
Sealed water tank 15 for storing the sealing water to provided the water sealed type connecting an exhaust line 16 of the vacuum pump 6, the water ring vacuum pump 6 the seal water to the sealed water tank 15 to the water sealing tank 15 And circulates between them to achieve the use of sealed water.
Then, the sealing water tank 15 is connected an overflow line 17. The treated water supply line 4 is provided with a flow switch 18.
And the controller 10 are connected by a signal line 9. Connect between the controller 10 and the water ring vacuum pump 6 through a signal line 9, and to perform the on-off control of the water ring vacuum pump 6. A pipe 19 for supplying treated water to the load side is connected to a lower part of the treated water tank 3.

According to the deaerator having the above-mentioned structure, the dissolved oxygen concentration (for example, up to the upper limit water level in the treated water tank 3)
1.0 ppm), and supplies the treated water via a pipe 19 at the request of the load side. By the supply of treated water to the load side, lowered water level of the treated water tank 3, the level sensor 7 detects a reduction level. Then, this detection signal is output to the controller 10 via the signal line 9. The controller 10 that has received the detection signal outputs a proportional control signal to the flow rate control valve 8 based on the water level and the raw water supply amount set in advance (see FIG. 3). The flow control valve 8 which has received the proportional control signal is opened so as to have a predetermined supply amount, and supplies a predetermined amount of raw water to the membrane module 2. Then, the water passing through the membrane module 2 flow switch 18 detects and outputs a detection signal to the controller 10. The controller 10 which has received the detection signal, water ring vacuum pump 6
Is driven to vacuum-evacuate the inside of the membrane module 2 to degas the raw water. The dewatered treated water flows into the treated water tank 3 via the treated water supply line 4.

The standard treated water volume of the membrane module 2 is, for example, 1000 liters per hour (raw water temperature 25 ° C.).
Assuming that the dissolved oxygen concentration after degassing is 1.0 ppm in FIG.
As shown in the figure, the water level of the treated water tank 3 is equal to the set water level L
Until the water storage rate drops to 50%, the raw water supply amount to be supplied to the membrane module 2 is proportionally adjusted based on the respective water levels. Therefore, as shown in FIG. 2, deaerated treated water (0.2 to 0.8 ppm) lower than the dissolved oxygen concentration of 1.0 ppm in the standard treated water amount can be obtained. When the amount of the treated water is equal to or less than the standard treated water amount, the deaerated treated water having a low dissolved oxygen concentration can be stored in the treated water tank 3.

[0022] Then, according to the control method of the present invention, the (if e <br/> it was 50% of the set voltage) from the level sensor 7 abnormal signal to the controller 10 when is outputted, the controller 10 Determines that an abnormality has occurred in the level sensor 7, opens the flow control valve 8 fully, and supplies a predetermined amount of raw water based on the operation of the upper limit water level detection device 11 provided in the treated water tank 3. Therefore, even when the level sensor 7 is abnormal, the supply of the treated water to the load side is not stopped.

[0023]

As described above, according to the present invention, the concentration of dissolved oxygen in the degassed treated water is set higher than the standard value.
Can be lowered and the level sensor is abnormal.
Avoid stopping the supply of treated water to the load, even at times
be able to.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a basic configuration of a deaerator suitable for carrying out the present invention.

FIG. 2 is an explanatory diagram showing the relationship between the temperature of raw water, the concentration of dissolved oxygen in treated water, and the amount of treated water in a deaerator.

FIG. 3 is an explanatory diagram showing a relationship between a water level in a treated water tank and a raw water supply amount.

FIG. 4 is an explanatory view schematically showing a configuration of a conventional deaerator.

[Explanation of symbols]

 Reference Signs List 1 Raw water supply line 2 Deaeration means (membrane module) 3 Treated water tank 7 Level sensor 8 Flow control valve 11 Upper limit water level detection device.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsufumi Isshiki 7th Horie-cho, Matsuyama-shi, Ehime Miura Industrial Co., Ltd. (72) Inventor Gen 7 Horie-cho, Matsuyama-shi, Ehime Mizuko Co., Ltd. Examination Shigehiro Toyonaga (56) References JP-A-3-207404 (JP, A) JP-A-57-122910 (JP, A) JP-A-6-170357 (JP, A) JP-A-8-266808 (JP, A A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 19/00-19/04

Claims (1)

(57) [Claims] 1. A raw water supply line 1 for supplying raw water, a degassing means 2 for degassing the supplied raw water, and a treated water tank 3 for storing degassed treated water. A level sensor 7 for detecting a water level in the water tank 3 is provided, and an upper limit water level detecting means 11 for detecting an upper limit water level in the treated water tank 3 is provided.
A flow control valve for controlling a supply amount based on a signal from the level sensor 7, wherein when the level sensor 7 is abnormal, the flow control valve 8 is
A method for controlling a deaeration device, wherein the deaeration device is fully opened and a supply amount of raw water supplied to the deaeration means 2 is controlled based on an operation of the upper limit water level detection means 11.