JP7211177B2 - Control method for pure water production device - Google Patents

Description

The present invention relates to a method of controlling a water purifier, and more particularly to a method of controlling a water purifier that processes raw water supplied from a raw water supply mechanism to produce pure water.

In a pure water production apparatus (for example, Patent Document 1) having a pressure pump, an RO device (reverse osmosis membrane separation device), a degassing device, an electrodeionization device, etc., the flow rate of permeated water, concentrated water, etc. is measured by a flow meter. Detect and control the pressure pump. In addition to the flow meter, the pure water production apparatus is provided with various sensors for measuring temperature, pressure, water quality (pH, electrical conductivity, silica concentration, etc.) and the like.

If air bubbles are mixed in the flowmeter, the detected value of the flowmeter may deviate greatly from the true value, and, for example, a detected value significantly larger than the true value may be output. In the conventional water purifier, when the detected value of the flow meter exceeds the standard value, the water supply amount of the pressure pump is reduced to protect the equipment such as the RO device, and the water purifier is stopped. Control is performed to set the stop mode. It is the same when abnormality occurs in other sensors.

Instead of stopping the water purifier, it is also being considered to continue the operation of the water purifier in a slow operation mode in which the amount of water supplied by the pressure pump is reduced.

JP-A-2004-167423

If there is no abnormality in the water purifying apparatus main body and the operation of the water purifying apparatus is stopped due to an abnormality in the sensor, or if the slow operation mode is set, the production efficiency of pure water decreases accordingly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of controlling a water purifier that can accurately determine whether a sensor installed in the water purifier is abnormal.

A method for controlling a pure water production apparatus according to a first aspect of the present invention is a method for controlling a pure water production apparatus for producing pure water by treating raw water in a pure water production apparatus having at least a pressure pump and an RO device, the method comprising: An alarm is output when the maximum detected value of the sensor provided in the water purifying apparatus exceeds a predetermined upper limit or the minimum detected value falls below a predetermined lower limit within a predetermined period of time.

A method for controlling a pure water production apparatus according to a second aspect of the invention is a method for controlling a pure water production apparatus for producing pure water by treating raw water in a pure water production apparatus having at least a pressure pump and an RO device, An alarm is output when a ratio of a difference between a maximum value and a minimum value detected by a sensor provided in the water purifying apparatus and an average value within a predetermined time is equal to or less than a predetermined value.

A method for controlling a pure water production apparatus according to a third aspect of the present invention is a method for controlling a pure water production apparatus for producing pure water by treating raw water in a pure water production apparatus having at least a pressure pump and an RO device, An alarm is output when the detected value of the flow meter installed with the pump on the upstream side becomes larger than the specified value of the discharge amount of the pump.

In one aspect of the present invention, the pure water production apparatus includes an RO apparatus installed in series in multiple stages, a deaerator for degassing permeated water from the RO apparatus in the final stage, and and an electrodeionization device to which the degassed water is supplied.

In the method for controlling a pure water production apparatus of the present invention, it is possible to accurately determine whether or not an abnormality has occurred in the sensor detection value of a flow meter or the like, regardless of the experience of the operator or the frequency of checking. is prevented from entering the stop mode or the slow operation mode unnecessarily, and an abnormality of the sensor is prevented from being overlooked.

1 is a configuration diagram of a pure water production apparatus showing an embodiment; FIG.

Embodiments will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the invention. Raw water from river water, well water, industrial water, recovered water, etc. is fed to the raw water tank 1 . The raw water in the raw water tank 1 is supplied to the first RO device 8 via the water supply pump 2 , pipe 3 , safety filter 4 , pipe 5 , pressure pump 6 and pipe 7 . The permeated water of the first RO device 8 is supplied to the second RO device 10 through the pipe 9, and the permeated water is supplied to the degassing device 12 through the pipe 11. The water degassed by the degassing device 12 is supplied to the electrodeionization device 14 through the pipe 13, and the permeated water is sent to the demand destination through the pipe 15 as pure water.

As the deaerator 12, various devices such as a membrane deaerator are used. In the membrane deaerator, water is passed through the primary side of the gas permeable membrane, and the pressure on the secondary side is reduced by a vacuum pump.

In addition, a branch pipe 17 is connected to the pipe 15 via a three-way valve 16, and the pure water from the pipe 15 is supplied to the raw water tank 1 (the pipes 3 and 5 or a water supply tank provided for them as necessary). good).

Further, pipes 18 and 19 for returning the concentrated water (first concentrated water and second concentrated water) of the RO devices 8 and 10 to the raw water tank 1 are provided. Although not shown, a line for returning the concentrated water from the electrodeionization device 14 to the raw water tank 1 is provided. Each of the pipes 9, 11, 18 and 19 is provided with a flow control valve (not shown).

The first concentrated water from the first RO device 8 is desalted and then returned to the raw water tank 1 . The second concentrated water from the second RO device 10 and the concentrated water from the electrodeionization device 14 are returned to the raw water tank 1 as they are.

A pressure sensor 20 for measuring the raw water supply pressure is provided in the pipe 3 (or pipe 5), flow meters 22 to 25 are provided in pipes 9, 11, 18, and 19, respectively, and the sensor 20 and the flow meters 22 to 25 is input to the control device 21 . Based on these input signals, the control device 21 performs PID control of the rotation speed of the pressurizing pump 6 so that the flow rate of each pipe 9, 11, 18, 19 is within the target range. , 18 and 19 are controlled.

The control device 21 includes a temperature sensor, a pressure sensor and a flow meter (flow rate sensor) provided at one or more locations of the pure water production apparatus, as well as a pH meter (pH sensor), water quality (electrical conductivity, silica concentration etc.) Detected values of various sensors such as sensors are input, and it is determined whether there is any abnormality in the operation of the pure water production equipment, and if it is determined that there is an abnormality, an alarm is sent to the management center or the mobile terminal of the operator etc.

In the present invention, it is determined whether or not an abnormality has occurred in the temperature sensor, pressure sensor, flow meter, pH meter, water quality sensor, etc. as follows. A sensor determined to be abnormal shall be repaired or replaced immediately or during the next maintenance.

[Judgment based on range over]
When the maximum value of the sensor detection value in the most recent predetermined time period (e.g., 24 hours, especially about 60 minutes) exceeds a predetermined upper limit value, or when the minimum value falls below a predetermined lower limit value, it is determined that an abnormality has occurred in the sensor. and output an alarm.

The predetermined upper limit is set as 95% of the output range of the sensor. However, 95% is an example, and may be selected from between 90% and 98%.

The predetermined lower limit is set as 5% of the output range of the sensor. However, 5% is just an example, and may be selected from between 2 and 10%.

[Determination based on the ratio of fluctuation range/average value]
The ratio of the fluctuation range of the detected value of the detected value of the sensor in the most recent predetermined time (for example, 24 hours, especially about 60 minutes), that is, the value of (maximum value - minimum value), and the average value of the detected value within the predetermined time [fluctuation width]/[average value] is less than a predetermined value, for example, less than a value selected from 2 to 20%, it is determined that the sensor is frozen and an alarm is output.

[Determination of Flow Meter Abnormality]
For a flow meter with a pump installed upstream of the flow meter, if the measured flow rate exceeds the specification value (catalog value) of the pump's discharge rate, it is determined that the flow meter has an abnormality. and output an alarm.

1 raw water tank 4 safety filter 6 pressure pump 20 pressure sensor 21 control device 22 to 25 flow meter

Claims (2)

Supplying raw water to the first RO device through the water supply pump, the first pipe, the pressure pump and the second pipe ,
supplying the permeated water of the first RO device to the second RO device through the third pipe;
The permeated water of the second RO device is supplied to the degassing device through the fourth pipe,
A method for controlling a pure water production apparatus for supplying degassed water from the degassing apparatus to an electrodeionization apparatus through a fifth pipe and subjecting it to electrodeionization to produce pure water,
Alarm when the maximum value within a predetermined time of the detection value of the flow meter provided in the first pipe, the third pipe, and the fourth pipe exceeds a predetermined upper limit value or the minimum value falls below a predetermined lower limit value A method of controlling a pure water production apparatus, characterized by outputting. The upper limit value is a value selected from 90 to 98% of the output range of the flow meter,
2. The method of controlling a pure water production apparatus according to claim 1, wherein said lower limit value is a value selected from 2 to 10% of the output range of said flow meter.

Images