JPS6235624B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water quality measuring device for low turbidity water, and particularly to a water quality measuring device that uses a membrane filter to intermittently measure clogging rate or clogging rate.

Recently, a membrane filter with a uniform fine pore size has been used as a water quality indicator to indicate the content of extremely small amounts (1 ppm or less) of suspended matter or colloidal substances in water, or the tendency of these substances to adhere to filter membranes. SI (Silting Index), FI (Fouling
Measuring methods such as PI (Index) and PI (Plugging Index) have been proposed and put into practical use. These water quality indicators have been proven to be very effective measurement tools for preventing membrane contamination during desalination processes such as reverse osmosis and electrodialysis, and for detecting adherent colloids in ultrapure water. However, the measurement does not need to be carried out continuously at all times, and it is common to check the measurement at regular intervals.

When such intermittent measurement methods are used, if the sample water is contaminated with microorganisms, even in small quantities,
There is a possibility that it may remain attached to the water passage part of the device, and it may grow in large quantities on the inner wall of the water tank or in the moist areas inside the piping until the next measurement.
It is possible that a large error will be given to the next measurement value. Therefore, in the past, in order to prevent such errors, it was necessary to wash the water passage part of the device with a large amount of sample water each time a measurement was taken, which wasted valuable water when measuring ultrapure water. Sample water was wasted.

This invention improves the shortcomings of the conventional equipment, and by installing an ultraviolet irradiation lamp in the water supply tank, the inside of the water supply tank is directly sterilized at the final stage of each measurement, and the generated ozone is removed from the equipment. It is an object of the present invention to provide a water quality measuring device for low turbidity water, which can be made to flow through a water passage section of the device, thereby sterilizing and purifying the device and eliminating measurement errors.

This invention consists of a test water supply tank, a filtration section, and a filtered water tank.
This water quality measuring device for low turbidity water is characterized in that an ultraviolet irradiation lamp is provided in the water supply tank.

Examples of the drawings will be described below. The drawing is a system diagram of the embodiment, where 1 is a water supply tank, 2 is a filtration section, and 3 is a filtered water tank. The water supply tank 1 consists of a closed pressurized tank, which includes a water supply pipe C1 having a valve V1 at the bottom, an overflow pipe C2 having a valve V2 slightly above the middle, a pressurizing pipe C3 having a valve V3 and a pressure reducing valve RV1 at the top, Also, a connecting pipe C4 has a valve V4 at the bottom, and a drain pipe C5 has a valve V5 at the bottom.
is in communication, and an ultraviolet irradiation lamp 4 is provided in the upper space. The ultraviolet irradiation lamp 4 is preferably one that irradiates ultraviolet rays with a wavelength effective for sterilization and ozone generation, and is generally a low-pressure mercury lamp with a mercury filling pressure of 0.1 mmHg, and a 253.7 nm and sterilizing line.
A device that emits ultraviolet light of 184.9 nm can be used.

The filtration section 2 has a pair of filtration disks 6A and 6B that are vertically opposed to each other so that the membrane filter 5 fed from a roll (not shown) can be joined or separated in an airtight manner. Ori,
Filtration chambers 7A and 7 are provided on the opposing surfaces of this filter plate, respectively.
B is provided. A water-permeable filter support plate 8 is provided on the upper surface of the lower filtration chamber 7B, and an exhaust pipe C having the communication pipe C4 and the valve V6 is provided.
6 is in contact. Further, a communication pipe C7A having a valve V7A and a branch pipe C7B having a valve V7B communicate with the upper filtration chamber 7A. Valve V7A and V
7B are interlocked so that when one is open, the other is closed. An air cylinder 9 is provided above the upper filter disk 6A, and a valve V8 and a pressure reducing valve
Pressure pipe C8 with RV2 is in communication. Note that the pressurizing pipes C3 and C8 are connected to the compressor 10.

The filtered water tank 3 is provided with a level switch 11 inside to enable measurement, and is connected to the communication pipe C7A at the top and the drain pipe C9 having a valve V9 at the bottom. Drain pipes C5 and C9, overflow pipe C2, exhaust pipe C6, and branch pipe C7B each communicate with drain pipe 12.

The method of measuring water quality using the water quality measuring device for low turbidity water configured as described above differs depending on the test item, but all of them are filtration tests using the membrane filter 5. The test method for automatic FI measurement will be explained below.

For automatic FI measurement, first open valve V1 and introduce sample water from water supply pipe C1 into water supply tank 1.
The valve V2 is opened to allow overflow for a certain period of time to equalize the sample water in the water supply tank 1 and to keep the liquid level constant. Then, close valves V1 and V2 and open valve V.
3 is opened and compressed air is introduced from the compressor 10 to pressurize the water tank 1.

On the other hand, in the filter section 2, the valve V8 is opened, compressed air is sent from the compressor 10 to drive the air cylinder 9, and the filter disk 6A is lowered and set. In this state, the membrane filter 5 is supported on the filter support plate 8, sandwiched between the filter disks 6A and 6B, and kept airtight in the filter chambers 7A and 7B. In this state, valve V
4. Open V6 to introduce pressurized water from the water supply tank 1, and vent the air in the filtration chamber 7B.

Next, valve V6 is closed and valve V7A is opened to begin measuring _T0 . _T0 is a measurement of the time required to filtrate a certain amount at the start of the test, and when a certain amount of filtrated water that has passed through the membrane filter 5 enters the filtrated water tank 3, the level switch 11 is checked and the time is measured. Then close valve V7A and
Filtration is performed by opening the valve V7B and discharging the filtered water from the branch pipe C7B for a certain period of time, and then measuring a certain amount of filtration time T ₁ after a certain period of time in the same manner as T ₀ above.
Thereafter, valves V5, V6, and V9 are opened to drain water from the entire apparatus, and one test is completed. To stop the supply of filtered water to the filtered water tank 3 during this time, use the valve V7.
Close A and open V7B.

These measurement operations are performed intermittently at regular intervals. During downtime, the sample water in the device is drained and
Although the apparatus is empty for the time being, some adhering water remains on the inner wall of the water supply tank 1, the inner surface of the piping, the inner wall of the filter section 2, the filter support plate 8, the filtered water tank 3, the inside of the electromagnetic valve, etc. If microorganisms such as bacteria and organic matter assimilated by them are present in the sample water, even in trace amounts, the organic matter will be concentrated and adsorbed on the wall surface that comes into contact with the sample water. It is expected that the cells will proliferate and accumulate during the rest period, giving rise to the possibility that errors will appear in subsequent measurements.

Therefore, in order to solve this problem, it is sufficient to sterilize the water flow part inside the device at the final stage of each measurement, but the injection of chemicals should be done the next time.
This is not a preferable method because it causes contamination during measurement.

The present invention uses ultraviolet irradiation, which does not necessarily cause contamination, and the ozone generated from the ultraviolet irradiation to sterilize the system. That is, after the automatic measurement sequence described above, the ultraviolet light irradiation lamp 4 installed inside the water supply tank 1 is turned on, and the inside of the water supply tank is sterilized by direct irradiation from this lamp, and all valves from V2 onwards are opened. The system is sterilized by adding a sequence in which a small amount of air is flowed from the compressor 10 and ozone generated by ultraviolet irradiation is flowed through all water passages, and then the valve V
3. Close V8 to stop pressurization, send out the membrane filter 5, and complete the measurement.

Sterilization by the combination of ultraviolet irradiation and generated ozone is very strong, and even a small amount of ozone, e.g.
The water tank is effectively sterilized by flowing air at 1 mg-O ₃ /-air for several minutes. In addition, when sterilizing the inside of piping, the filter section, the electromagnetic valve, etc., although no ultraviolet irradiation is used, a sufficient sterilizing effect can be achieved by passing air at the ozone concentration for several minutes.

In the above apparatus, compressed air is used as the water supply pressurizing means, but a pump or other pressurizing means may be used, and the installation position of the ultraviolet lamp 4 is not limited to the upper space, but may be at another position. Good too. The structure of the filtration section 2 is not limited to that of the embodiment, but may be of any other structure as long as it can perform a filtration test through a membrane filter. Also, filtered water tank 3
The measuring means in is not limited to the one in the embodiment, but may be of another type, or may not be provided with a measuring means. Further, the present invention is not limited to FI measurement, but can also be applied to a water quality measuring device for low turbidity water that measures clogging rate, clogging speed, etc. using other indicators such as PI and SI.

As described above, according to the present invention, the following effects are recognized.

Since the inside of the water flow system of the device can be kept sterile during the downtime, it is possible to prevent errors in subsequent measurements due to the growth of microorganisms within the system.

In order to minimize the above-mentioned error, in the conventional method, sample water was run for a considerable period of time to clean the system before measurement, but this amount of water can be saved.

In the conventional method, the water used for measurement was discarded because there was a possibility of contamination from within the system, but now it is possible to use this water.

Especially when measuring ultrapure water, the above effects greatly contribute to lowering the cost of automatic monitoring.

Since sterile water is produced intermittently, sterile water can also be used for cleaning instruments, etc.

[Brief explanation of the drawing]

The drawing is a system diagram of the embodiment, and 1 is a water supply tank, 2 is a filtration unit, 3 is a filtered water tank, 4 is an ultraviolet irradiation lamp, 5 is a membrane filter, 6A and 6B are filter plates, 9 is an air cylinder, and 10 indicates a compressor. 〓〓〓〓

Claims (1)

[Scope of Claims] 1. Water quality of low turbidity water that is composed of a test water supply tank, a filtration section, and a filtered water tank, and is measured by passing low turbidity test water from the water supply tank through a membrane filter in the filtration section. A water quality measuring device for low turbidity water, characterized in that the measuring device includes an ultraviolet irradiation lamp installed in a water supply tank. 2. The water quality measuring device for low turbidity water according to claim 1, wherein an ultraviolet irradiation lamp is provided in the upper space of the water supply tank. 3. The water quality measuring device for low turbidity water according to claim 1 or 2, wherein the ultraviolet irradiation lamp irradiates ultraviolet rays effective for sterilization and ultraviolet rays effective for ozone generation.