JPH06221509A - Control method of raw water supplying amount for deaerating device - Google Patents

Abstract

PURPOSE:To provide raw water supplying amount control method capable of obtaining deaerated water having a preset concentration of dissolved oxygen with good balance, in a deaerating device. CONSTITUTION:A deaerated water supplying line 3, constituted of a temperature sensor 4, water supplying pump 5 and a deaerating device 6 for removing dissolved gas in the raw water, is connected between a raw water supplying unit 1 and a deaerated water tank 2 equipped with a water level sensor 2a while a controller for controlling the operation of the water supplying pump 5 and the deaerating device 6 is provided. The deaerated water, having a preset predetermined dissolved oxygen concentration, is secured in the deaerated water tank 2 and the amount of raw water supplied to the deaerating device 6 is regulated in accordance with the outlet amount of deaerated water supplied from the deaerated water tank 2 whereby a water level in the deaerated water tank 2 is maintained so as to be higher than a predetermined water level (L3) while securing the dissolved oxygen concentration lower than the predetermined value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for increasing / decreasing the amount of raw water supplied according to the temperature of the raw water supplied in a deaerator applied to a heat equipment such as a boiler or a water supply line to a building, an apartment or the like. Is.

[0002]

2. Description of the Related Art As is well known, a water supply line for cooling and heating equipment such as a boiler, a water heater or a cooler is equipped with a deaerator for the purpose of preventing internal corrosion of these equipment. Further, in recent years, deaeration devices have come to be used as a measure for preventing red water in water supply and distribution pipes in buildings, condominiums, and other structures. In this deaerator, a membrane deoxygenation module is connected in the water supply line to the equipment used, and raw water (tap water, well water, other industrial water) is passed through this deoxidation module, In the water process, the inside of the deoxygenation module is evacuated to degas the dissolved gas in the raw water.

By the way, the deaerator has a characteristic that, as shown in FIG. 2, if the amount of treated water is constant, the dissolved oxygen concentration of the treated water increases as the temperature of the raw water supplied decreases. Therefore, the dissolved oxygen concentration is low in the summer when the water temperature is high, and the dissolved oxygen concentration is high in the winter when the water temperature is low. It's a problem. Therefore, it is necessary to introduce a degassing device having a large processing capacity that can obtain degassed water having a predetermined dissolved oxygen concentration at a predetermined flow rate even at a low temperature.

[0004]

In view of the above problems, the present invention detects the water temperature of the raw water to be supplied and constantly detects the water level of the degassed water tank to obtain degassed water having a preset dissolved oxygen concentration. Therefore, it is an object of the present invention to provide a control method for adjusting the amount of raw water supplied to the deaerator.

[0005]

That is, according to the present invention, between a raw water supply unit and a deaeration water tank equipped with a water level sensor,
A temperature sensor, a water supply pump, and a degassing water supply line for removing dissolved gas in raw water are connected to the degassed water supply line, and a controller for controlling the operation of the water supply pump and the degassing device is provided. Based on the raw water temperature signal from the water level signal from the water level sensor, secure degassed water of a preset predetermined dissolved oxygen concentration in the degassed water tank, degassed water supplied from this degassed water tank According to the amount of effluent water, by adjusting the supply amount of raw water to be supplied to the deaerator, while maintaining a dissolved oxygen concentration below a predetermined value, maintaining the water level in the degassed water tank above a predetermined water level There is.

[0006]

According to the present invention, the temperature sensor detects the water temperature of the raw water and reports it to the controller, and the water level sensor of the degassed water tank detects the water level and reports it to the controller. The relation between the temperature of raw water and the amount of treated water in the deaerator with respect to the dissolved oxygen concentration in the raw water is calculated and controlled so that an appropriate amount of raw water can be sent to the deaerator. Accordingly, the water level in the degassed water tank is maintained at or above the predetermined water level while ensuring the dissolved oxygen below the predetermined value.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view showing the arrangement of each device in a degassed water supply line 3 embodying the present invention. The raw water supply unit 1 and the water level sensor 2a of the degassed water supply line 3
The temperature sensor 4, the water supply pump 5, and the deaerator 6 are connected to the deaerated water tank 2 provided with. A controller 8 for controlling the operation of the water supply pump 5 and the deaerator 6 is provided by the signals from the water level sensor 2a and the temperature sensor 4. Reference numeral 7 in the figure is a line.

Since the water level sensor 2a employs an ultrasonic type displacement sensor, it constantly detects the water level in the degassed water tank 2 and outputs a water level detection signal to the controller 8 via the line 7. It is supposed to do. In addition, the temperature sensor 4
Detects the water temperature of the raw water and outputs an electric signal to the controller 8 via the line 7. The water supply pump 5 includes the controller 8
The flow rate is variable by controlling the number of revolutions by an inverter (not shown) installed inside the.

In the deaerator 6, a deoxygenation module is connected in the deaerated water supply line 3, raw water is passed through the deoxygenation module, and the deoxidation module is supplied with water in the course of the water passage. Is evacuated to remove the dissolved gas in the raw water by degassing. In this type of deaerator 6, a water-sealed vacuum pump (not shown), which has a simple structure and is inexpensive, is used as a means for vacuuming. The degassed water that has been degassed flows into the degassed water tank 2 and is supplied to each device from the bottom of the degassed water tank 2 through the treated water supply line 9.

The controller 8 stores the relationship diagram between the raw water temperature, the dissolved oxygen concentration in the treated water, and the treated water amount shown in FIGS. 2 and 3, and the numerical value of the correction coefficient. , The water level lines L ₁ , L ₂ and L ₃ set in the degassing water tank 2 calculate the related numerical values based on the signals from the temperature sensor 4 and the water level sensor 2a, and the degassing device 6 processes them. The discharge amount of the water supply pump 5 is adjusted by controlling the inverter so as to supply the amount of raw water that can be treated.

Next, the operation of the raw water supply control method for the deaerator will be described. When the raw water is supplied from the raw water supply unit 1 (for example, the raw water tank) to the degassed water supply line 3 by driving the water supply pump 5, the temperature sensor 4 detects the temperature of the raw water and an electric signal is sent via the line 7 to the controller. Output to 8. Controller 8
Determines the raw water temperature signal from the temperature sensor 4 and sets the preset dissolved oxygen concentration in deaerated water (for example, 0.5 ppm).
In order to secure the water consumption, the treated water amount that can be treated by the deaerator 6 is calculated based on the relational numerical value between the raw water temperature and the treated water amount (see FIG. 2 and FIG. 3), and the inverter is controlled by the numerical value to control the feed pump. The rotation speed of 5 is changed to supply a predetermined amount of raw water to the deaerator 6. The deaerator 6 vacuum-deaerates the inside of the deoxygenation module and supplies deaerated water having a predetermined dissolved oxygen concentration to the deaerated water tank 2.

On the other hand, the water level sensor 2a is the deaerated water tank 2
The water level inside is linearly detected and reported to the controller 8, and the controller 8 determines the amount of water flowing out from the tank 2 from the change in the water level in the degassed water tank 2 and the discharge amount of the water supply pump 5. And
When the amount of water flowing out from the tank 2 is less than the minimum discharge amount that can be controlled by the water supply pump 5, the water level level at which the number of times of starting and stopping the water supply pump 5 does not become excessive is calculated as L _2, and the top of the degassed water tank 2 is determined. The water level is set to L ₁ , the pump 5 is driven with the minimum discharge amount at a water level of L ₂ or higher, and the pump 5 is stopped when the water level reaches the water level of L ₁ . When the amount of water flowing out from the tank 2 is larger than the minimum discharge amount of the pump 5, PID control is performed based on the water level difference from the L ₁ level and the water level fluctuation amount. That is, the PID control is a control that combines a proportional operation, an integral operation, and a differential operation from the water level fluctuation amount of the discharge amount of the pump 5 that changes from the raw water temperature and the water amount that flows out from the tank 2. Therefore, when the amount of water flowing out from the tank 2 is larger than the maximum flow rate of the raw water supplied to the deaerator 6 (the maximum flow rate capable of maintaining the dissolved oxygen concentration below a predetermined value), which is obtained from the raw water temperature, the feed water is supplied. The pump 5 operates at the obtained maximum discharge amount, and when the water level drops to the lower limit water level L ₃ of the tank 2, the water supply pump 5
Is operated with a discharge amount of the amount of water according to the amount of water flowing out, and is balanced with the amount of water flowing out from the tank 2. Then, when the water level in the tank 2 becomes L ₃ or higher, the pump discharge amount control based on the raw water temperature is restored.

Next, an embodiment replacing the above embodiment will be described with reference to FIG. As shown in FIG. 4, the degassed water supply line 3
A bypass line 10 is provided with the water supply pump 5 inserted between the bypass line 10 and the electric operation valve 11 inserted into the bypass line 10.
The operation valve 11 is connected to the controller 8 via the line 7. In order to ensure a predetermined dissolved oxygen concentration (0.5 ppm) of the degassed water set in advance by the electric signal of the temperature sensor 4, a controller based on the relational numerical value between the raw water temperature and the treated water amount of the degassing device 6. The reference numeral 8 sends a signal to the operation valve 11 to open the valve, and causes a part of the raw water to flow into the bypass line 10 to adjust the raw water to be supplied to the deaerator 6 to a predetermined amount and supply it. The structure and operation other than those described above are the same as those of the above-described embodiment, and thus the description thereof is omitted.

[0014]

As described above, according to the present invention, since degassed water having a preset dissolved oxygen concentration is supplied, the controller uses the signals from the temperature sensor and the water level sensor to control the required degassed water. By controlling the balance between the amount of water and the amount of raw water to be supplied, degassed water having a predetermined dissolved oxygen concentration can be maintained at a high water level in a low load state. Therefore, there is a large margin against temporary overload, and it is economical without increasing the size of the deaerator more than necessary. Also, even in the overloaded state,
Since the water supply pump is operated with the discharge amount of the water amount according to the outflowing water amount, not the maximum discharge amount of the water supply pump, the deviation from the set dissolved oxygen concentration is small, and the rise of the dissolved oxygen concentration can be suppressed to the minimum.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the arrangement of each device in a degassed water supply line showing an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between raw water temperature, treated water-soluble oxygen concentration and treated water amount in a deaerator.

FIG. 3 is a diagram showing the effect of raw water temperature on treatment with a dissolved oxygen concentration of 0.5 ppm.

FIG. 4 is an explanatory diagram showing an arrangement of each device in a degassed water supply line showing an embodiment replacing the embodiment of FIG.

[Explanation of symbols]

 1 ... Raw water supply unit 2 ... Deaerated water tank 2a ... Water level sensor 3 ... Deaerated water supply line 4 ... Temperature sensor 5 ... Water supply pump 6 ... Deaeration device 8 ... Controller

Claims (1)

[Claims] 1. A temperature sensor 4, a water supply pump 5, and a deaerator 6 for removing dissolved gas in raw water are inserted between a raw water supply unit 1 and a deaeration water tank 2 equipped with a water level sensor 2a. And a controller 8 for connecting the deaerated water supply line 3 and controlling the operation of the water supply pump 5 and the deaeration device 6,
Based on the raw water temperature signal from the temperature sensor 4 and the water level signal from the water level sensor 2a, deaerated water having a predetermined dissolved oxygen concentration set in advance is secured in the deaerated water tank 2, and the deaerated water tank 2 Depending on the amount of degassed water supplied from
The amount of raw water supplied to the deaerator 6 is adjusted to maintain the water level in the degassed water tank 2 at or above a predetermined water level (L ₃ ) while ensuring a dissolved oxygen concentration below a predetermined value. Method for controlling the amount of raw water supplied to a degassing device.