JPH0716567A - Ultrafiltration type drinking water device - Google Patents

Abstract

PURPOSE:To supply sterile water stably for a long period of time and prevent the undesirable effect of the variation in water quality on an experiment by providing an ultrafilatration membrane module for purifying raw water and a restoration device to be used when the membrane performance is lowered in a drinking water supply line for animals used for the experiment. CONSTITUTION:In the operation of filtration, raw water (service water) is supplied to a hollow fiber type membrane module 6 through a strainer 1, a pressure reducing valve 2, an electric motor valve 3, a three-way valve 4 and the like, and filtration is performed in the module. Filtered water is transferred to an automatic water supply breeding rack through an electric motor valve 7 or the like to supply the drinking water to experimental animals, When the filtration is carried out for the given time, a drain solenoid valve 9 is opened periodically, while the electric motor valve 7 is closed, and polluted substances are removed by flashing the raw water, and after the given time, the electric motor valve 7 is opened and the drain solenoid valve 9 is closed to restart the filtration. At the time of radial flow backwashing, raw water pressure is increased by closing the electric motor valve 7 and then the drain solenoid valve 9 is opened to release the pressure all at once and discharge the polluted substances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drinking water purification apparatus and a water supply method for laboratory animals in the medical field and the like.

[0002]

2. Description of the Related Art The problem of drinking water of experimental animals in the medical field is GLP (standard for conducting safety tests of pharmaceuticals:
With regard to the Ministry of Health, Labor and Welfare Yakuhin No. 313 (1982), it has been attracting attention as one of the environmental factors that affect the experimental results, as well as feed (nutrition). In recent years, more precise and reproducible demands have been made for animal experiments on drugs, and drinking water is considered to have a large effect only on those that directly enter the body of experimental animals, and stricter control of water quality is required. Has been done.

However, since tap water is usually used as drinking water, there is a problem due to the water quality and microbiological cleanliness. For example, we have overlooked the effects of microorganisms such as bacteria and viruses such as Pseudomonas aeruginosa contained in trace amounts, and organic compounds such as pyrogens, humic substances, polyhalogenated organic compounds and fluorescent dyes on animal drug testing. In some cases, even with the same drug test, test results may differ due to regional differences in water quality.

Therefore, conventionally, in many laboratory animal breeding facilities, a system in which tap water is filtered by a cylindrical microfilter or the like which blocks particles of about 5 μm or more and supplied to animals is generally adopted. With the micro filter method,
It is impossible to prevent microorganisms and organic compounds, and there are problems such as adhesion of green algae on the filter surface, instability of water amount, and growth of various bacteria. In addition, the microorganisms attached and accumulated on the surface of the filter when the filter is replaced are contaminated and diffused.

On the other hand, there is also a method of sterilizing drinking water by autoclave treatment, but depending on the amount of treatment, the drinking water temperature rises to 37 ° C when the internal cylinder temperature of the autoclave reaches 120 ° C, and rises to 87 ° C even after 40 minutes of heat treatment. In some cases, large-scale processing requires a long time. Both methods pose problems in terms of safety and efficient work as described above.

On the other hand, the tap water, which is the drinking water, is supplied to the laboratory animals by the stored water such as the water bottle and the water tray (not shown) shown in FIG. 4 and the automatic water feeding rack shown in FIG. Since animals drink water by putting their mouths directly on water supply nozzles of water bottles and automatic watering racks, the nozzles are inevitably contaminated with live bacteria. In addition, in the case of a breeding facility with an automatic water feeding / raising rack, there is a risk of so-called reverse contamination, in which microorganisms such as viable bacteria diffuse from the water supply nozzle through the piping of this rack to the source line of tap water (raw water).

[0007]

As one of the methods for solving the above problems, the use of semipermeable membranes such as reverse osmosis membranes, ultrafiltration membranes and microfiltration membranes, which have been studied in various fields in recent years, can be considered. . Among them, the reverse osmosis membrane also removes inorganic ions and chlorine added to tap water because the pore size of the membrane that separates solutes is too small. In contrast to the reverse osmosis membrane, the microfiltration membrane has an excessively large pore size, so that inorganic ions and added chlorine and the like can permeate, but there is a risk of leakage of pyrogens and bacteria.

On the other hand, the ultrafiltration membrane can permeate inorganic ions, added chlorine, etc. to remove pyrogens and bacteria, but in the case of total permeation, the permeation rate rapidly decreases with the permeation amount. This phenomenon is due to the fact that microsuspended substances in the raw water deposit on the membrane surface and resist water permeation.

Conventionally, for such a membrane having a reduced filtration capacity, for example, intermittent passage of raw water, flushing of raw water,
Membrane performance such as air bubbling, mechanical vibration of the membrane or physical abrasion of membrane deposits, or backwash method (hereinafter referred to as backwash) that allows water or gas to permeate in the opposite direction of filtration It is known that if the recovery operation is performed intermittently, the membrane surface dirt can be removed while the apparatus is running without stopping the apparatus, and the water permeability of the membrane is recovered. Of these, backwashing with water is a particularly effective and desirable method, but when it is used in a drinking apparatus of a laboratory animal facility, there are the following problems.

1) When raw water is used as backwash water, the permeate side is contaminated with fine particles, viable bacteria, pyrogen, and the like.

2) Of course, it is only necessary that the backwash can be performed with permeated water or clean water supplied separately.
To carry out backwashing in the usual way, permeate or clean water storage tank, pressurized pump for backwashing, or compressed air,
Huge equipment such as incidental equipment to keep them sterile is required.

[0012]

In order to solve the above-mentioned problems and meet the demands in the medical field, the inventors of the present invention have made earnest studies, and as a result, have found that an ultrafiltration membrane and a recovery mechanism for deterioration of membrane performance, particularly a specified mechanism. By using the cleaning mechanism of, the simple structure without the need for large auxiliary equipment, the water amount does not decrease due to the clogging of the membrane even if it is used for a long time, and the leakage of pyrogens and bacteria and the supply line to the raw water are prevented. We have completed a drinking water device for experimental animals that can prevent the reverse contamination of microorganisms such as live bacteria.

That is, the present invention is characterized in that the drinking water supply line for experimental animals is provided with an ultrafiltration membrane module for purifying raw water and a recovery mechanism for deterioration of the membrane performance. Of the ultrafiltration type drinking device.

Examples of the shape of the ultrafiltration membrane module used in the ultrafiltration type drinking apparatus of the present invention include spiral type, plate-and-frame type, tube type, pleated type and hollow fiber type. Among them, the hollow fiber type membrane module is particularly desirable. The hollow fiber membrane module has a large filtration membrane area per unit volume, can be backwashed, and has little dead space in the space where the treatment liquid flows,
This is because it is suitable for applications in which trace amounts of impurities are disliked.

The filtration method using the hollow fiber membrane module includes an internal pressure filtration method in which raw water is supplied into the hollow of the hollow fiber to obtain permeated water outside the hollow fiber, and a raw water is supplied in the outside of the hollow fiber. There is an external pressure filtration method for obtaining permeated water in the hollow of the hollow fiber, and either method may be used in the present invention, but an internal pressure filtration method in which uneven flow hardly occurs and uniform filtration is more preferable.

The molecular weight cutoff of the ultrafiltration membrane is not particularly limited, but the range of molecular weight cutoff effective for the purpose of the present invention is 5,000 to 10,000, more preferably 5,000 to 50,000. Is.

As a mechanism for recovering deterioration of membrane performance in the ultrafiltration type drinking apparatus of the present invention, especially when a hollow fiber type membrane module is used, raw water flushing (for example, JP-A-58).
-163406), underflow backwash (for example, JP-A-63-
111995), accumulator flushing backwash (for example,
JP-A-60-197206) or mutual backwashing (see, for example, JP-A-60-166003) is preferable because it is simple, and at least one of them may be adopted. The operation of the recovery mechanism for the deterioration of the membrane performance may be performed periodically, or when the pressure rise due to clogging is detected and a certain pressure is reached, or it may be automatically activated. Alternatively, it may be manually operated. In addition, as a control valve provided in the raw water inlet line and the membrane permeated water outlet line of the hollow fiber type membrane module due to the recovery mechanism of these membrane performance deterioration, the animals can be operated even when the device is stopped due to a power failure or a failure. An electric motor valve that holds the open state when the current is cut off is used so that the power can be supplied.

In addition, in the present invention, when water is given to an animal through a water supply nozzle of an automatic watering / raising rack, it is guaranteed when an ultrafiltration membrane module is leaked, and a microorganism derived from an experimental animal is used as raw water. In order to more reliably prevent the back-contamination of the supply source line of U, as shown in FIG.
It is also preferable to add a physical sterilizer such as a V lamp sterilizer, an electrolytic sterilizer, and a sterilizing acidic ionized water supply device by electrolysis. Here, the physical sterilization means a method that is not sterilization by adding a chemical agent such as a bactericide.

[0019]

[Examples] In the following, the configuration of the ultrafiltration type drinking apparatus of the present invention is used in which the tap water is used as raw water and the hollow fiber type membrane module is used as the ultrafiltration membrane module in the internal pressure filtration method, and the recovery mechanism for the deterioration of the membrane performance is periodically performed. However, the present invention is not limited to this embodiment.

Embodiment 1 In FIG. 1 showing an example of the constitution of an ultrafiltration type drinking apparatus according to the present invention, a mechanism for recovering deterioration of membrane performance includes a raw water electric motor valve (3) and a permeated water electric motor valve (7). , Drainage solenoid valve
(9) and an electronic circuit (not shown) for automatically controlling the opening and closing of these valves by a timer. During the filtration operation, the raw water electric motor valve (3) and the permeate water electric motor valve (7) are open, the drainage solenoid valve (9) is closed, and tap water flowing from the raw water inlet under the raw water pressure is strained. (1), pressure reducing valve (2), raw water electric motor valve (3), three-way valve (4) and inflow water pressure gauge
After passing through (5), it is supplied to the hollow fiber type membrane module (6), and the whole amount is filtered. The filtered permeate is supplied to an automatic water feeding rack (not shown) via the permeate electric motor valve (7) and the permeate pressure gauge (8).
Alternatively, it is collected in a water bottle or the like and used for drinking water of experimental animals.

The operation of the recovery mechanism for the deterioration of the membrane performance, which is regularly performed, is to open the drainage solenoid valve (9) and then close the permeate electric motor valve (7) to perform the raw water flushing operation. Fouling is removed, but first, the raw water electric motor valve (3) is closed,
After that, close the permeate electric motor valve (7) and open the drainage solenoid valve (9), and then feed the raw water electric motor valve.
(3) may be opened. After flushing the raw water for a predetermined time, the permeated water electric motor valve (7) is opened, and then the drainage solenoid valve (9) is closed to return to the filtering operation.

In the case of performing the backwash backwash operation, the permeated water electric motor valve (7) is closed in FIG. 1 for a predetermined time to increase the pressure on the raw water side, and then the drainage solenoid valve (9) is opened for a predetermined time. As a result, the pressure is released all at once, and the raw water is discharged for a predetermined time to wash out fouling (pollutants). In this case, close the raw water electric motor valve (3) and the permeate electric motor valve (7) at the same time, then
(3) may be opened to increase the pressure on the raw water side. Close permeate electric motor valve (7), raw water electric motor valve
With the (3) open, open and close the drainage solenoid valve (9).
~ Repeat 3 times. Close the raw water electric motor valve (3) once, then close the drainage solenoid valve (9), then open the raw water electric motor valve (3) and restart the filtration operation.

In the case of pressure flushing backwashing, a hollow fiber type membrane module is installed upright in FIG. 1 and a part of this permeated water is extracted to the upper part of the permeated water side in the module filled with permeated water. Due to the negative pressure generated, a gas such as air or nitrogen is introduced while sterilizing with a sterilizing filter to form a gas layer and hermetically seal, and then the filtration operation is started. The backwashing operation may be performed in the same manner as in the case of underflow backwashing. The difference from the backflow backwash in this case is that a gas layer is provided in advance on the permeate side in the module.

In the backflow backwash or pressure flushing backwash, the permeated water electric motor valve (7) is closed for a predetermined time,
Instead of increasing the pressure on the raw water side, this increase in pressure is detected as the pressure difference between the inflow water pressure gauge (5) and the permeate water pressure gauge (8), and when this pressure difference exceeds the set value, the drainage electromagnetic force is detected. valve
(9) may be opened.

Of course, these recovery operations for deterioration of the membrane performance can be carried out by appropriately combining two or more kinds of operations.

Example 2 In addition, two hollow fiber type membrane modules were used as an example of the constitution of the ultrafiltration type drinking apparatus by mutual backwashing, which is another mode of the recovery mechanism for the deterioration of the membrane performance applied to the present invention. FIG. 2 shows the combination. In Fig. 2, the recovery mechanism for the deterioration of the membrane performance consists of the raw water electric motor valve (12), (12 '), the permeate electric motor valve (14), the drainage solenoid valve (15), (15') and these valves. It consists of an electronic circuit (not shown) for automatic control periodically by a timer. During the filtration operation, the raw water electric motor valves (12), (12 ') and the permeate electric motor valves (14) are fully opened, and the drainage solenoid valves (15), (15') are closed. The tap water flowing in due to the raw water pressure passes through the strainer (10) and the pressure reducing valve (11), and is branched into two raw water electric motor valves (12) and (12 ') to obtain two hollow fiber membrane modules ( It is supplied to 13) and (13 ') respectively, and the whole amount is filtered. The permeated water from the two membrane modules is collected and supplied to an automatic water feeding / raising rack (not shown) via the permeated water electric motor valve (14), or is collected in a water bottle or the like and stored in a laboratory animal. Served for drinking water.

The operation of the recovery mechanism for the deterioration of the membrane performance due to mutual backwashing is such that raw water is not supplied to any one of the two membrane modules, that is, one raw water valve (12).
Close the other raw water valve (12 ') with the valve open, and simultaneously open the drainage solenoid valve (15') and open the permeate valve (1
If the opening of 4) is adjusted, for example, if it is closed about half, the membrane module (13) continues the filtration operation state, so the total amount of permeated water is halved. It is continuously supplied to the outlet line, and the remaining half of the membrane module has no water pressure on its raw water side and the water pressure (back pressure) from the membrane module (13) on its permeate side. By being sent back to 13 '), backwashing of the other membrane module is performed with the permeated water obtained from one membrane module periodically for a predetermined period of time according to a setting program, and fouling is removed. Next, the membrane module
If the membrane (13) and the membrane module (13 ') are reversed, then the membrane module (13) is backwashed. As described above, according to the ultrafiltration-type drinking water device by mutual backwashing, backwashing can be performed while continuing to supply the treated water to the animal. FIG. 2 shows an example using two membrane modules, but it goes without saying that more membrane modules can be used.

The operation of these recovery mechanisms for deterioration of membrane performance is as follows.
Usually, it is performed once a day on a regular basis, and the washing time in one operation is usually repeated for 1 to 5 times within a period of 10 seconds to 20 minutes.

Long-term continuous test Using polyethersulfone resin as a membrane material,
FUS-0353 (product number) manufactured by Daicel Chemical Industries, Ltd. with an outer diameter of 0.5 mm / 0.8 mm and a molecular weight cut off of 30,000, and a pure water permeation rate of 1.8 m ³ / h filled with a hollow fiber ultrafiltration membrane. The raw water is supplied from the tap water line using the module of kg / cm ² , and the pressurizing time of 3 is applied in the ultrafiltration type drinking apparatus of the present invention shown in FIG.
The cycle of washing for 25 seconds and then for 25 seconds is repeated twice, and recovery operation of the deterioration of the membrane performance due to backwash is performed once a day, while effective filtration pressure (differential pressure) of about 0.5 kg / cm ² , permeation As a result of performing internal pressure filtration at a speed of about 3.0 liters / min and performing a long-term continuous operation for 6 months, there was almost no decrease in water permeation rate and normal operation was possible.

Sterilization effect In the above hollow fiber type membrane module, ground water is used as raw water, and 1.3 × 10 ⁴ enterococci are inoculated into this model, and the total number of viable cells is 2.1 × 10 ⁴ per ml. As a result of conducting a sterilization effect test by performing filtration treatment using the liquid, it was confirmed that no bacterium was detected in the permeated water.

[0031]

According to the present invention, even if it is used for a long time, there is almost no decrease in water pressure or permeation rate due to clogging of the membrane,
Aseptic water can always be supplied, and the problem of the effects of microorganisms and organic substances contained in raw water is eliminated.
In addition, processing time, work efficiency,
It is excellent in both energy cost and so on. Furthermore, since there is no diffusion of contamination by microorganisms when exchanging the membrane in the conventional tubular filter system, and bacteria etc. possessed by the experimental animal are blocked by the ultrafiltration membrane, the experimental animal can be fed to the source line of raw water from the experimental animal. It is possible to prevent reverse contamination of the bacteria and the like.

[Brief description of drawings]

FIG. 1 is a flow diagram showing a configuration of an ultrafiltration type drinking apparatus of the present invention.

FIG. 2 is a flowchart showing another configuration of the ultrafiltration type drinking apparatus of the present invention.

FIG. 3 is a flow diagram showing one configuration of an ultrafiltration type drinking water device to which a physical sterilization device of the present invention is added.

FIG. 4 is a view showing a water bottle for experimental animals.

FIG. 5 is a view showing an automatic water feeding / raising rack.

[Explanation of symbols]

 1 Strainer 2 Pressure reducing valve 3 Raw water electric motor valve 4 Three-way valve 5 Inflow water pressure gauge 6 Hollow fiber membrane module 7 Permeate water electric motor valve 8 Permeate water pressure gauge 9 Drainage solenoid valve 10 Strainer 11 Pressure reducing valve 12 Raw water electric motor valve 12 'Raw water electric motor valve 13 Hollow fiber membrane module 13' Hollow fiber membrane module 14 Permeate electric motor valve 15 Drainage solenoid valve 15 'Drainage solenoid valve 16 Ultrafiltration device 17 Physical sterilization device 18 Nozzle 19 Drinking water 20 Pressure gauge 21 Pressure reducing valve 22 5 μm filter 23 Solenoid valve 24 Timer 25 Tube 23 Nozzle

Claims (9)

[Claims] 1. An ultrafiltration apparatus for laboratory animals, comprising an ultrafiltration membrane module for purifying raw water and a recovery mechanism for deterioration of membrane performance in a drinking water supply line for laboratory animals. Water drinking equipment. 2. The ultrafiltration-type drinking water device for experimental animals according to claim 1, wherein the ultrafiltration membrane module is a hollow fiber membrane module. 3. The recovery mechanism for membrane performance deterioration using a hollow fiber membrane module is at least one selected from raw water flushing, underflow backwashing, pressure flushing backwashing and mutual backwashing. Ultrafiltration drinking water equipment. 4. The ultra-thin according to claim 3, wherein the raw water inlet line and the membrane permeated water outlet line of the hollow fiber type membrane module are provided with current motor valves for holding the open state when the current is cut off. Filtered drinking water device. 5. The ultrafiltration-type drinking water device according to any one of claims 1 to 4, wherein a physical sterilizer is provided on the membrane permeated water outlet side of the ultrafiltration membrane module. . 6. The ultrafiltration-type drinking water device according to claim 1, wherein the drinking water is supplied to the laboratory animal by an automatic watering and feeding rack. 7. A method of supplying water to a laboratory animal, which supplies drinking water through a water supply nozzle of an automatic watering and feeding rack, wherein an ultrafiltration membrane is used and the raw water is subjected to a filtration treatment while performing a recovery operation for reducing the membrane performance. A method of supplying drinking water for laboratory animals, characterized by supplying the water to an automatic water supply rack after purification. 8. The method for supplying drinking water for laboratory animals according to claim 7, wherein the ultrafiltration membrane is a hollow fiber type membrane. 9. The method for supplying drinking water for laboratory animals according to claim 7, wherein a physical sterilization treatment is used in combination with the purification treatment with the ultrafiltration membrane.