JPS58114796A - Method and device for aeration - Google Patents

Abstract

PURPOSE:To remove the foreign matter between an impeller and a casing easily, by stopping a motor which drives the impeller and opening a remote control valve provided in a bypass pipe of an air feed pipe when the axial driving force of the motor exceeds a rated value then running the motor backward then forward and closing the valve. CONSTITUTION:When an underwater motor 5 is driven to run an impeller 4 forward, a material to be treated is sucked through a suction port 9 as shown by an arrow E and is discharged through a discharge port 10 as shown by an arrow F. During this time, air is injected to the material through an air diffusion pipe 11. Thereupon, when wooden pieces, vinyl, etc. are jammed in the spacing 4a between the impeller 4 and the inside surface of an outer casing 7, a valve 21 of a bypass pipe 20 is opened and the motor 5 is stopped. When the motor 5 is run backward for several tens seconds, the wooden pieces, vinyl, etc. are removed. Thereupon, the motor 5 is run forward again, and the valve 21 is closed to start normal operation.

Description

Detailed Description of the Invention The present invention provides a flow path for a liquid to be treated between inner and outer casings, and controls the stopping, reverse rotation, forward rotation, etc. of a motor that drives an impeller provided in the flow path. The present invention relates to an aeration method in which the opening and closing of a bypass pipe of a supply pipe of a WIs-containing gas injected toward a liquid to be treated is controlled by a series of sequence controls, and an apparatus for carrying out the method.

Subject I]! Blowing air into a liquid, such as sewage, to purify the sewage chemically or biologically is a well-known method for purifying sewage, and has been applied as a J3 air system.

For example, the conventional aeration system @B shown in Fig. 1 is composed of a driving part and a casing part C, and the whole is suspended by a chain 2 via a hanging fitting 1, and is used at the bottom of a processing tank. It looks like this. In this way, since the air system WIB is used in liquid, the underwater motor 5 is used as the motor of the drive section A, and the impeller 4 is rotationally driven by the underwater motor 5. The casing part C consists of an inner casing 6 and an outer casing 7, between which a flow channel 8 is formed. Both casings 6.7 are flared downwards.

The aeration device B configured in this way has a submersible motor 5.
When the impeller 4 is started, the impeller 4 is driven to rotate, and the liquid to be treated is sucked in from the suction port 9 above the flow path 8, and is discharged radially outward from the discharge port 10. Then, an appropriate number of diffuser pipes 11 protrude from the flow path 8 to supply air! 12
An oxygen-containing gas, such as air, supplied from the diffuser pipe 11 is injected into the liquid to be treated via the annular collecting pipe 13.

By the way, in the conventional one-air device having such a structure, the air diffuser 11 protrudes into the flow path 8, so foreign matter such as dust in the processing liquid gets caught in the air diffuser 11, causing the air diffuser 11 to protrude into the flow path 8. The disadvantage is that it blocks the This is because in aeration tanks, especially those for sewage treatment, various solid materials such as wood chips, vinyl chips, etc. flow into the aeration tank together with the sewage. When these foreign substances block the flow path 8, the driving power of the motor increases, causing the motor to exceed its output rating, and sometimes even causing the motor to trip.

Therefore, various aeration devices have been proposed to prevent the adhesion of tribute as described above. However, these proposed devices have the disadvantage of being complex and expensive. The cheapest way to remove foreign matter is to reverse the impeller to cause the liquid to flow backwards. By the way, in the aeration device having the discharge port 10 as described above, the aeration pipe 11 is located downstream of the blade 1lI4, so if the air supply pipe 12 is temporarily closed and the motor, that is, the impeller is not reversed, it will restart. When this occurs, the normal flow is not reversed.

What happens is, if you reverse the impeller while supplying air,
This is because the bubbles coming out of the air diffuser 11 flow in the direction reflected by the arrow E in the channel 8, and at the same time generate a water flow in that direction. That is, unless the air supply pipe is closed before the impeller is reversed, the aeration system cannot be restarted and operated normally even if the impeller is reversed and foreign matter is removed. In order to remove foreign matter using this inexpensive method, the air supply pipe must be closed, but in places such as sewage treatment plants where all equipment is remotely controlled, the on-off valves installed in the air supply pipe must also be remotely controlled. However, since the air supply pipes generally have a large diameter of 75 to 150 m1, a new drawback arises in that installing a large solenoid valve in these pipes becomes expensive.

The present invention was made in view of the various circumstances described above, and uses a small and inexpensive remote control valve, such as a solenoid valve, to remove foreign matter by reversing the cheapest impeller. The purpose of this invention is to provide a method and apparatus for doing so all at once.

According to the present invention, the air supply pipe is preferably provided with a bypass pipe having a smaller diameter than this pipe, and the bypass pipe is provided to control forward rotation, stop, reverse rotation, stop, normal rotation, etc. of the motor that drives the impeller. The system is designed to perform sequence control of remotely controllable valves.

An embodiment of the apparatus according to the present invention will be described below with reference to FIG. In FIG. 2, the same components as in FIG. 1 are given the same reference numerals. In the illustrated embodiment, the air supply pipe 12
rises upward and protrudes to the liquid level S of the liquid to be treated, and is connected to a high pressure source (not shown). The oxygen-containing gas supplied by the air supply line is generally air, and a compressor is used as the high pressure source.

The air supply pipe 12 is a pipe with a large diameter of 75 to 1501 Ill, and a bypass pipe 20 branches off from this pipe above the liquid level. The bypass pipe is a pipe with a smaller diameter than the air supply pipe 12, preferably 1/2 or less of the air supply pipe 12, and has a remotely controllable valve 21 above the liquid level, for example 1! A magnetic valve is installed. Further, the open end 22 of the bypass pipe 20 is submerged in the liquid to be treated, and the depth h thereof is different from that of the aeration pipe 11.
The depth is less than 1/2 of the depth.

Next, an aeration method for carrying out the present invention will be explained. When the underwater motor 5 is started, the impeller 4 rotates normally, and the liquid to be treated is sucked in from the suction port 9 as shown by the arrow E, and is discharged from the ejection port 10 as shown by the arrow F. Meanwhile, from diffuser pipe 11! A metal-containing gas, for example air, is injected towards the liquid to be treated. By the way, if the gap 4a between the outer periphery of the impeller 4 and the inner surface of the outer casing 7 is clogged with pieces of wood, vinyl, etc., the valve 21 of the bypass pipe 20 is opened and the motor 5 is stopped. Then reverse the motor. Then, due to this reversal, the foreign matter stuck between the impeller and the outer casing is removed. After the motor is rotated in the reverse direction for several seconds or several tens of seconds, the motor is rotated in the normal direction again, the valve 21 is closed, and normal operation begins. According to the present invention, the bypass pipe 20 opens at a depth of 1/2 or less of the diffuser pipe 11, so the air flow resistance is
Bypass pipes are much smaller. Therefore, the oxygen-containing gas is not injected into the flow path 8 from the diffuser pipe 11, but is released from the bypass pipe 20 into the liquid reservoir. Therefore, even if the impeller is reversed, the air bubbles will not flow backwards. Therefore, a normal flow can be easily obtained by restarting after reversal.

As described above, according to the present invention, foreign matter is removed by an inexpensive method of reversing the impeller, and since the valve is installed in a bypass pipe with a relatively small diameter, it is inexpensive to configure it as a solenoid valve. It can be provided to Furthermore, since the bypass pipe opens into the treated liquid, there is an advantage that the sewage purification action can be carried out even while the impeller is being rotated in reverse to remove foreign matter.

Now, when carrying out the present invention, the control of stopping, reverse rotation, stopping, forward rotation, etc. of the underwater motor 5 and the control of the valve of the bypass pipe are controlled in sequence. Clogging of the outer periphery of the impeller 4 with foreign matter is detected by detecting that the motor output exceeds the rated value. When an excess is detected, a remotely controllable valve, such as a solenoid valve 21, in the bypass pipe 20 is opened, and the motor is stopped. The stop time is set, for example, to several seconds by a timer, taking into consideration the rotational inertia of the motor 5 and the impeller. After that, the motor 5 is reversed, and the reversal time is set to several seconds to several tens of seconds. Next, the reverse rotation is stopped, the motor is then rotated in the normal direction, and the valve 21 is closed to begin normal operation. The above series of operations is performed by sequence control.

As described in detail above, according to the present invention, foreign matter stuck between the impeller and the casing can be removed by the extremely simple operation of reversing the motor, that is, the impeller, and the electromagnetic material used in connection with the reversing operation can be removed. Although the valve was a small and inexpensive one, it was sufficient to accomplish the purpose, and its effectiveness was great.

[Brief explanation of the drawing]

Figure 1 is a side view partially showing a conventional aeration device;
The figure is a partially sectional side view showing an example of an aeration device embodying the present invention. 4... Impeller 5... Motor 6... Inner casing 7... Outer casing 11... Air diffuser pipe 12... Air supply pipe 20... Bypass pipe 2
1...Remotely controllable valve (I solenoid valve) No. FG Procedural Amendment Written by the Commissioner of the Patent Office, March S, 1981 Shima 1) Haruki Tono 1, Indication of Facts Patent Application No. 1983-209595 2
, Title of the invention Aeration method and aeration device 3 Relationship with person making the amendment A 1 Applicant 11 Place January 1, No. 4, Haneda Asahi-cho, Ota-ku, Tokyo Agent address: 105 (11!Ii 1!Kyoto Port) Nishi-Shinbashi 1-1018
No. Nishishin Building 4th floor 5, Date of amendment order Voluntary amendment G, Subject of amendment -7 of the detailed explanation of the invention in the play, Contents of amendment (1) 1. Defective tracheal pipe 11 at the end of page 3 of the specification. ``...'' to the third line of page 5 of the same page, ``pay before...'' will be corrected as follows. The impeller and the outer casing 7 may become clogged with foreign matter. This is because in aeration tanks, especially aeration tanks for sewage treatment,
This is because solid materials such as wood chips, vinyl chips, etc. flow into the aeration tank along with the sewage. When these foreign objects become stuck between the impeller and the outer casing, they increase the driving power of the motor, causing the motor to exceed its output rating or even tripping the motor. Therefore, various aeration devices have been proposed that are designed to prevent the above-mentioned foreign matter from accumulating. However, what is the structure of these proposed devices? It has the disadvantage of being complicated and expensive. The cheapest way to remove tribute is to use an impeller. It is to reverse it. By the way, in the aeration system having the discharge port 10 as described above, since the aeration pipe 11 is located downstream of the impeller 4, if the air supply pipe 12 is not closed for one day before restarting normal rotation, the problem will occur when restarting. Normal flow cannot be obtained. If air is being supplied during reverse rotation or stoppage, the air bubbles coming out of the air diffuser 11 will flow in the flow path 8 in the direction of arrow E and reflection, at the same time creating a strong water flow in that direction, and the engine will continue to rotate forward. This is because normal flow cannot be obtained even if the In other words, before the impeller restarts and rotates normally, the feeder is checked.April 2, 1980, Director General of the Japan Patent Office Minoru Shima 1) Haruki Tono1, Indication of the case Patent application @56-109595 No.2, Invention O Name Aeration method and aeration device 3, person making amendments and orb person Address 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Name (6)
13) EHa Seisakusho Co., Ltd. and 1 other representative Seiji Kan Hatakeyama 4, Michihito 〒! @Is 5. Date of amendment order Voluntary amendment, t 6. Subject to amendment O. @ Detailed explanation of q4 in specification O column/'] ＼ L Contents of amendment (1) The date of March 3, 1939 is a personal record. Amendment sheet 02 page “
Correct "Foreign object with outer casing" in the 0th line after "O" to "Foreign object between outer casing and O connection."

Claims (1)

[Claims] <1) An impeller for flowing a liquid to be treated is provided between the inner and outer casings, and when the impeller is driven by a motor, the liquid to be treated flows between the two casings. In an aeration method in which oxygen-containing gas is injected into the liquid to be treated through an air supply pipe, when the shaft power of the motor exceeds the rated value, the motor is stopped and at the same time a 52 (t) is inserted into the bypass pipe of the air supply pipe. An aeration method characterized in that the motor is rotated in the reverse direction for a predetermined period of time and then in the forward direction, and the front control valve is closed. (2) The flow of the liquid to be treated between the inner and outer casings is A supply device having a flow path formed therein, an impeller for flowing the liquid to be treated in the flow path, a motor for driving the impeller, and a supply for injecting oxygen-containing gas toward the liquid to be treated in the flow path. In an aeration device equipped with a trachea, the air supply pipe has a bypass pipe branched above the surface of the liquid to be treated, and the diameter of the bypass pipe is smaller than the diameter of the air supply pipe, and the diameter of the bypass pipe is smaller than the diameter of the air supply pipe. An aeration vtM characterized in that the open end opens below the surface of the processing liquid via a remote control valve provided on the blade above the liquid surface.