JPH02131107A - Cross flow filter provided with particle feed device, particle feed method, and back washing method - Google Patents

Abstract

PURPOSE:To equalize differencial pressure of filtration by providing a particle feed device with an automatic control mechanism at an inlet line connected to a cross flow filter and further providing an automatic control valve mechanism. CONSTITUTION:Raw water in a raw water tank 1 is pumped up to be introduced into a cross flow filter 6 through an inlet line 2 so that the raw water is caused to flow parallel to the film surface of a branch pipes 7a. The raw water flowing parallel with the film surface is contacted therewith to be filtered and separated, while the clarified water is filtered and discharged to the outside of a main body pipe 7b. A filtration differencial pressure gauge 40 provided between the inlet line 2 and a discharge water line 8 judges whether differencial pressure is within a set value or not, whereby when differencial pressure is within the set value, a command YES is delivered to close a flow control valve 22 of a particle feed device 20 or to set said valve at specified opening. In the latter case, a specified quantity of particles is mixed into the raw water in the inlet line 2 through a line 21. In this manner, precise filtration can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a cross-flow filtration device equipped with a particle feeding device incorporating a particle feeding device into a cross-flow filtration system, a particle feeding method, and a backwashing method. be.

"Prior Art" Conventionally, as a filtration method with excellent filtration separation accuracy, a cross-flow filter that can perform filtration while forming a flow of raw water flowing parallel to the filtration membrane surface has been used.

In order to ensure the best filtration efficiency of this cross-flow filter, the properties of raw water, raw water concentration, filtration flow rate, average pore diameter of the filter medium, etc. must be properly maintained and controlled, and ultimately the filtration differential pressure must be controlled. Constant monitoring and maintenance is essential.

Also, similar technical documents include JP-A-82-21
Cross-flow filtration method of No. 3817, JP-A-63-126
Cross-flow type precision filtration method of No. 511, JP-A-63-
There is a backwashing method in cross-flow precision filtration as disclosed in No. 126513, and a flocculant injection control device as disclosed in JP-A No. 63-200807.

"Problems to be Solved by the Invention" In order to effectively and efficiently maintain and manage the aforementioned cross-flow filtration device, various requirements are required.
Specifically, requirements such as understanding the properties of raw water, the filtration flow rate, and maintaining the filtration differential pressure close to the set value are required.

It is also important that these be done with relative precision.

However, as a practical matter, the properties of the raw water, the filtration flow rate, etc. constantly change depending on the raw water condition, dust condition, etc.

For this reason, it is considered quite difficult to maintain and manage it optimally at all times.

Furthermore, constant monitoring of the filtration differential pressure and reliable maintenance and management is also a problem, as in the case described above.

Furthermore, although the above-mentioned technical literature can be expected to have some effects, it is limited to only a one-dimensional improvement and is still not sufficient. Improvements have been made only by intermittent adjustment of the inflow rate and backwashing via bypass pipes.

Therefore, it is difficult to say that a loss flow filtration device is low cost, simple, and easy to operate, and the current situation is that it has not been used for normal raw water treatment.

"Means for Solving the Problem" In view of the above, the present invention provides an automatic method for preventing the filtration differential pressure of the cross-flow filter from increasing. In addition to being equipped with a particle supply device having a control mechanism, an automatic control valve mechanism is installed in a pipe connected to the inflow pipe, and the particle supply is controlled through a filtration differential pressure gauge provided between the inflow pipe and the drain pipe. Activating the automatic control mechanism of the device and/or the automatic control valve mechanism of the distribution piping,
The objective is to achieve substantially uniformity of the filtration pressure difference in the filtration member of a cross-flow filter.

Furthermore, the automatic control mechanism of the particle supply device and the automatic control valve mechanism of the distribution piping described above operate individually or simultaneously when the filtration differential pressure gauge installed between the inflow pipe and the drain pipe detects a pressure equal to or higher than a set value. Because of this configuration, it is possible to contribute to automation and labor saving, as well as to appropriately maintain and manage the filtration differential pressure.

Furthermore, in order to ensure a sufficient amount of water during backwashing, the cross-flow filter is configured to have sufficient volume to prevent leakage of pressurized gas introduced into the cross-flow filter and injection into the filter member. It is expected that it will be effective and that a rapid backwashing effect can be expected.

In addition, the above-mentioned backwashing is configured to operate when the filtration differential pressure gauge installed between the inflow pipe and the drain pipe detects the upper limit value, so it reliably prevents clogging of the crossflow filter. These operations can be automatically controlled, greatly contributing to labor savings.

"Function" The present invention will be described in detail below. When the large mouth valve of the inflow pipe is opened, the pumped-up raw water in the raw water tank is introduced into the cross-flow filter through the inflow pipe, and the ceramic Membrane filter A parallel flow is formed on the membrane surface of a filtration member such as a cellulose membrane filter, and this parallel flowing raw water is separated into RW through contact with the membrane surface.
The clear water flows to the outside of the filtration member, and the waste liquid containing dust (in the present invention, in principle, is treated as waste liquid) further rises within the filtration member, where it is further separated and filtered.

The clarified water separated and filtered as described above is temporarily stored in the cross-flow filter and then led to the clarified water tank via the opened filtration outlet valve and the drain pipe.

On the other hand, the waste liquid is basically guided again to the inflow pipe via the flow pipe connected to the filtering member and mixed with the raw water from the raw water tank, and thereafter follows the same process as described above.

In this way, during the raw water treatment process, when the filtration differential pressure gauge installed between the inlet pipe and the drain pipe detects a filtration differential pressure higher than the set value, the flow control valve is opened or closed via the automatic control device. By varying the opening angle, particles (cross-flow filtration accelerator) are mixed into the raw water flowing through the inlet pipe, and the filtration differential pressure is restored to the set value.

It is also possible to control the amount of waste liquid flowing into the inflow pipe together with and/or separately from the supply of the particles. Such a slow flow rate of the filter member greatly affects the filtration efficiency.

Therefore, in the raw water treatment process or particle supply process, when the filtration differential pressure gauge installed between the inflow pipe and the drain pipe detects a filtration pressure difference greater than the set value, the flow control valve of the automatic control valve device is activated. By varying the opening angle and controlling the suction amount of waste liquid into the flow pipe, the flow rate in the pipe of the filter member can be controlled, or in conjunction with the above-mentioned mixing of particles into the raw water flowing through the inflow pipe, the above-mentioned filtration can be carried out. Immediately restore the differential pressure to the set value.

The process returns to the normal raw water treatment described above via the operating means described above. That is, closing or throttling the flow control valve of the particle supply device,
Stop the supply of particles or reduce the supply amount. Simultaneously or independently, the flow rate control valve is throttled to control the amount of waste liquid sucked into the flow pipe, thereby controlling the flow rate in the pipe of the cross-flow filter, thereby returning to normal raw water treatment.

In addition, when the filtration differential pressure gauge detects the upper limit value during the raw water treatment process, it means that the filtration member of the cross-flow filter is clogged and should be immediately backwashed. This situation needs to be avoided.

Therefore, in the present invention, when the above-mentioned situation occurs, the large mouth valve of the inflow pipe, the flow rate control valve of the distribution pipe, and the filtration outlet valve of the drain pipe are closed via the automatic control device, and the backwash valve of the high-pressure gas supply device is closed. In addition, the backwash blow valve of the waste liquid pipe is opened, and the so-called backwash route pipe is opened. In this case, since sufficient clear water is secured in the cross-flow filter, the clear water is pressurized without leaking of the high-pressure gas introduced through the drain pipe. This results in
The clear water passes through the filter member and reaches the inside of the filter member while removing or peeling off dust clogging the filter holes of the filter member or dust adhering to the inner surface of the filter member.

Thereafter, the dust is discharged together with the clear water from the outlet of the filtration member into the raw water tank via the distribution piping and the waste liquid pipe.

By repeating the above operations, when the filtration differential pressure gauge recovers to the set value, this time, the backwash valve of the high-pressure gas supply device and the backwash blow valve of the waste liquid pipe are closed via the automatic control device. and close the backwash root pipe.

At the same time, the inlet valve of the inflow pipe and the filtration outlet valve of the drain pipe are opened to return to the raw water treatment described above.

The above operations are automatically controlled continuously or intermittently to perform precision filtration of raw water.

``Embodiment'' An embodiment of the present invention will be specifically described below with reference to the drawings.

First, for convenience of explanation, a cross-flow filtration device equipped with a particle supply device will be described. 1 is a raw water tank, and an inflow pipe 2 that opens into the raw water tank 1 is provided with a population valve 3, a filtration pump 4, and an inlet valve 5, respectively. The opening at the other end communicates with the cross-flow filter 6.

This cross-flow filter 6 has a volume that can secure a sufficient amount of water for backwashing, and is made of a filter material such as a ceramic membrane filter or a cellulose membrane filter, preferably a racemic membrane filter, and is As shown, a filter member 7 consisting of a branch pipe line 7a and a main body pipe line 7b is installed inside.

A drain pipe 8 for discharging clear water is connected to a slightly lower part of the center of the cross-flow filter 6, and this drain pipe 8 is provided with a filtration outlet valve 9 and a flow meter 10, and the mouth end thereof is connected to a clear water tank. It has reached 11.

Further, a concentrated water blowing pipe 12 is connected to the lower converging portion 6a of the cross-flow filter 6, and this concentrated water blowing pipe 12 is provided with a concentrated water blowing valve 13, and its downward opening is connected to a concentrated water tank 14. It has arrived.

Further, a flow pipe 15 for distributing waste liquid is communicated with the outlet of the filter member 7, and this flow pipe 15 is branched at its tip, one of which is connected to a flow meter 16 and a flow control valve 17 operated by an automatic control device. The other end is connected to the inflow pipe 2 through the inflow pipe 2, and the other end is connected to the waste liquid pipe 18 which opens into the raw water tank 1. 19 is a backwash blow valve provided in the waste liquid pipe 18.

In the figure, 20 is a particle supply device provided in the inflow pipe 2, and this particle supply device 20 includes a particle supply pipe 21 communicating with the inflow pipe 2, and a measurement value of a filtration differential pressure gauge, which will be described later, provided in this pipe. and a flow rate control valve 22 whose opening/closing or opening degree is controlled via an automatic control device, a flow meter 23, a particle tank 24, a stirring blade 25 for stirring equipped in this particle tank 24, and a liquid level sensor 26. It consists of This particle supply device 2
0 is an example.

In the figure, reference numeral 30 denotes a gas supply device for backwashing. It is composed of a wash valve 32 and a pressurized gas tank 33, and the backwash valve 32 is automatically opened and closed via an automatic control device. still,
This high pressure gas supply device 30 for backwashing is one example.

In the figure, reference numeral 40 denotes a filtration differential pressure gauge provided between the inflow pipe 2 and the drain pipe 8, and in this example, it is provided via connecting pipes 41 and 42, but is not necessarily limited to this example.

In the figure, 50 is a safety valve device.

Next, the method of the present invention will be explained with reference to the flowcharts of FIGS. 2 and 3. When the inlet valve 3.5 of the inflow pipe 2 is open, the raw water in the raw water tank is introduced into the cross-flow filter 6 via the inflow pipe 2, and forms a flow that flows parallel to the membrane surface of the branch pipe 7a of the filter member 7 installed here, and the raw water that flows parallel to the membrane surface. The clear water is separated and filtered through contact with the branch pipe 7a, and the clear water is sent to the outside of the branch pipe 7a, and the waste liquid containing dust is sent to the outside of the branch pipe 7a.
After being separated and filtered in step a, the main body pipe line 7b of the filter member 7
It is further separated and filtered, specifically,
The purified water is filtered and discharged to the outside of this main body pipe 7b.

As described above, the separated and filtered clear water is temporarily stored in the cross-flow filter 6 and then guided to the clear water tank 11 via the opened filtration outlet valve 9 and the drain pipe 8. .

On the other hand, the waste liquid is basically guided again to the inflow pipe 2 via the flow pipe 15 communicating with the main body pipe 7b of the filter member 7, and is mixed with the raw water from the raw water tank 1. After that, the above-mentioned procedure is carried out. Follow a similar process.

In this way, during the raw water treatment process, as shown in Figure 2, the inlet pipe 2
The filtration differential pressure gauge 41 installed between the and the drain pipe 8 (STI)
, to determine whether it is within the set value ST 2), and if it is within the set value, a YES command is issued, and the particle supply device 20
The flow rate control valve 22 is closed or has a predetermined opening degree (S
T3), and in the case of the opening degree, a predetermined amount of particles are mixed into the raw water in the inflow pipe 2 via the pipe 21. Similarly, the flow control valve 17 of the automatic control valve mechanism has a predetermined opening degree (Sr1
). The so-called raw water treatment described above continues.

When one or more of the set values is detected, a No command is issued and the flow rate IJ 81 valve 2 is sent via the automatic control device.
2 is opened or its opening angle is varied ST5), the particles are mixed into the raw water flowing through the inflow pipe 2, and the amount of supplied particles is measured with the flow meter 23 (ST8). After that, give feedback and judge whether it is within the set value.5T2
), and thereafter the process is similar to that described above.

Furthermore, the flow rate within the cross-flow filter 6 can be varied in conjunction with and/or individually with the supply of the particles, and specifically, such a slow flow rate of the filter member 7 has a large effect on the filtration efficiency. This is the place to do it.

Therefore, when one or more of the set values is detected in the raw water treatment process or the particle supply process, a No command is issued and the opening angle of the flow rate control valve 17 is varied via the automatic control device (5T105). , the flow rate of the flow pipe 15 is varied to control the intake amount of waste liquid into the flow pipe 15), and the flow speed within the filtration member 6 is changed, and the flow speed of the flow pipe 15 is changed.
5 is measured by the flow meter 16 (S7106). Thereafter, it is fed back to determine whether it is within the set value described above (ST2), and thereafter the same process as described above is followed.

The process returns to the normal raw water treatment described above via the operating means described above. That is, the flow rate control valve 22 of the particle supply device 20 is closed or turned on, and the supply of particles is stopped or the supply amount is controlled. At the same time or independently, the flow rate control valve 17 is activated, and the flow piping 15 is activated.
By controlling the amount of waste liquid sucked into the tube and controlling the flow rate in the pipe of the filter member 6, normal raw water treatment is resumed.

In addition, in the raw water treatment process, as shown in Fig. 3, the filtration differential pressure gauge 41 (ST20) determines whether it is at the upper limit of the set value (5T21), and if it is below the upper limit, a YES command is issued, and the particle The flow rate control valve 22 of the supply device 20 is closed or opened to a predetermined degree (ST22), and if the flow rate control valve 22 is opened, a predetermined amount of particles are mixed into the raw water in the inflow pipe 2 via the pipe 21. Similarly, the flow rate control valve 17 of the automatic control valve mechanism has a predetermined opening degree (ST23). The process returns to the process of determining whether the raw water treatment described above is continued or whether the values are within the set values shown in FIG. 2 described above.

On the other hand, when the upper limit value or more is detected, the filtering member 7 of the cross-flow filter 6 is clogged during boat fishing, so it is necessary to promptly backwash or otherwise avoid this situation.

Therefore, in the present invention, when the above-mentioned situation occurs, a No command is issued and the artificial valve 3 of the inflow pipe 2 is sent via the automatic control device.
．． 5 and the filtration outlet valve 8 of the drain pipe 8 are closed, and the backwash valve 32 of the high-pressure gas supply device 30 and the waste liquid pipe 18 are closed.
Open the backwash blow valve 19 (5T24.204) to open the so-called backwash root pipe. As a result, the timer starts counting (ST25.205). While the timer is operating, the backwash valve 32 or the backwash blow valve 19 remains open, and pressurized gas is supplied into the crossflow filter 6 from the drain pipe 8 (ST27). In this case, since sufficient clear water is secured in the cross-flow filter 6, the clear water is pressurized without leaking of the high-pressure gas introduced via the drain pipe 8. As a result, the clear water passes through the narrow holes of the filter member 7 and reaches the inside of the filter member 7 while removing dust and the like that are clogging the thin wire holes on the filter membrane surface of the filter member 7.

The dust, together with the clear water, is discharged from the outlet of the filter member 7 to the raw water tank 1 via the flow pipe 15 and the waste liquid pipe 18 (ST207).

On the other hand, when the counter is completed, this backwashing work ends (ST26.206).

After repeating the above operations, give feedback to determine whether the set value is at the upper limit.5T21), Y
If it is ES, the backwash valve 32 of the high-pressure gas supply device 30 and the backwash blow valve 19 of the waste liquid pipe 18 are closed via the automatic control device, and the backwash route pipe is closed, as described above. . At the same time, the artificial valve 3.5 of the inflow pipe 2 and the filtration outlet valve 9 of the drain pipe 8 are opened, and the process returns to the raw water treatment described above.

The above operations are automatically controlled continuously or intermittently to perform precision filtration of raw water.

"Effects of the Invention" As described in detail above, the present invention provides an automatic control mechanism for the inflow pipe connected to the cross-flow filter, as a means of preventing an increase in the filtration differential pressure of the cross-flow filter. At the same time, the pipe connected to the inflow pipe is equipped with an automatic control valve mechanism, and the particle supply equipment is controlled via a filtration differential pressure gauge installed between the inflow pipe and the drain pipe. By operating the automatic control mechanism and/or the automatic control valve mechanism of the flow piping, substantially equalization of the filtration differential pressure within the filtration member of the cross-flow filter is achieved.

Therefore, improving the filtration efficiency of the cross-flow filter,
Prevents clogging of the filtration member and ensures constant precision filtration.

Furthermore, the automatic control mechanism of the particle supply device and the automatic control valve mechanism of the distribution piping described above operate individually or simultaneously when the filtration differential pressure gauge installed between the inflow pipe and the drain pipe detects a pressure equal to or higher than a set value. Because of this configuration, it is possible to contribute to automation and labor saving, as well as to appropriately maintain and manage the filtration differential pressure.

In addition, since the inflow pipe is equipped with a particle supply device and the amount of waste liquid sucked into the distribution pipe is controlled, the flow rate of the cross-flow filter can be varied and clogging control can be performed at low cost and through simple devices or methods. It is extremely effective.

Furthermore, in order to ensure a sufficient amount of water during backwashing, the cross-flow filter is configured to have sufficient volume to prevent leakage of pressurized gas introduced into the cross-flow filter and injection into the filter member. It is expected that it will be effective and that a rapid backwashing effect can be expected.

In addition, the above-mentioned backwashing is configured to operate when the filtration differential pressure gauge installed between the inflow pipe and the drain pipe detects the upper limit value, so it reliably prevents clogging of the crossflow filter. These operations can be automatically controlled, greatly contributing to labor savings.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 is a block diagram of the entire device, Fig. 2 is a flowchart showing particle supply or flow rate control, and Fig. 3 is a flowchart showing the backwashing situation. . 1: Raw water tank 2: Inflow pipe 3. 6: Population valve 4: Pump 6: Cross flow filter 7: Filtration member 7a: Branch pipe 7b = Main body pipe 8: Drain pipe 9: Filtration outlet valves 10, 16. 23:
Flow meter 11: Clarified water tank 12: Concentrated water blow pipe 13: Concentrated water blow valve 14: Concentrated water tank 15: Distribution piping 17.2
2: Flow rate control valve 18: Waste liquid pipe 19: Backwash blow valve 20
: Particle supply device 21.31.42.43: Piping

Claims (3)

[Claims] (1) A raw water tank, a cross-flow filter with a capacity to store a sufficient amount of water for backwashing, an inflow pipe that communicates the cross-flow filter and the raw water tank, and a system equipped with this inflow pipe. A particle supply device equipped with an automatic control mechanism, a drain pipe through which clear water discharged from the cross-flow filter flows, and a filtration waste liquid discharged from the cross-flow filter flows;
and a flow pipe for distributing waste liquid that communicates with the inflow pipe via an automatic control valve mechanism, a waste liquid pipe for backwash waste liquid used during backwashing that is branched from the flow pipe, and the cross-flow filter. a concentrated water blow pipe equipped with a concentrated water blow valve provided in the main body, a concentrated water tank to which this concentrated water blow pipe opens, a filtration differential pressure gauge provided between the drain pipe and the inflow pipe, and this filtration differential pressure gauge. The automatic control mechanism and/or
Alternatively, a cross-flow filtration device comprising a particle supply device comprising an automatic control device that automatically controls an automatic control valve mechanism, and a filtration outlet valve and a flow meter provided in the drain pipe. (2) The flow rate of raw water supplied from the raw water tank via the inflow pipe to a cross-flow filter having a capacity to store enough water for backflow, and the clarification drained from the cross-flow filter via the drain pipe. Detect the flow rate of water, guide the flow rate to a filtration differential pressure gauge, measure the differential pressure, and if the filtration differential pressure exceeds a certain value, introduce particles into the inflow pipe from a particle supply device connected to the inflow pipe. A particle supply device configured to promote filtration and/or control the flow rate of the flow piping and the filtration member of the cross-flow filter via a flow meter installed in the piping, and to maintain the filtration differential pressure at a constant value at all times. Particle feeding method in a cross-flow filter equipped with. (3) The flow rate of raw water supplied from the raw water tank via the inflow pipe to a cross-flow filter having a capacity to sufficiently store water for backflow, and the clarification drained from the cross-flow filter via the drain pipe. Detect the flow rate of water, guide the flow rate to a filtration differential pressure gauge, measure the differential pressure, and when the filtration differential pressure detects the upper limit, filter the flow rate control valve of the distribution piping, the inlet valve of the inflow pipe, and the drain pipe. After closing the outlet valve, opening the backwash valve and backwash blow valve, and opening the backwash pipe, pressurized gas is introduced into the crossflow filter to remove the backwash remaining in the crossflow filter. The water is pressurized and then backwashed to the raw water tank, and this backwashing process is repeated using a timer or the like.
A method for backwashing in a cross-flow filter comprising a particle supply device configured to close the backwash valve and the backwash blow valve to perform normal filtration processing when the filtration differential pressure deviates from an upper limit value.