JPH0515999Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an aeration device for an aeration tank used when treating wastewater such as sewage with activated sludge.

(Prior Art) As an aeration device for an aeration tank, in addition to an aeration plate made of a porous material, a membrane-like aeration device is conventionally known. As shown in FIG. 5, this membrane diffuser has a membrane 51 with a slit of about 1 mm attached to a pipe-shaped holder 50 with a hollowed out center.
It has a structure in which both ends thereof are closely fixed to the holder 50. Then, air enters between the membrane 51 and the holder 50 that supplies pressurized air from the small diameter pipe 52, and the air becomes bubbles from the slits in the membrane 51 and is diffused. The outer diameter is 50 to 60 mm, and the length is 8 to 12 times the outer diameter.

However, such a conventional device has no problem when operated at an airflow rate of about 50 to 150/min, but when the airflow rate is increased to, for example, about 500/min, the membrane 51 swells greatly and the slits of the membrane 51 become There was a problem that it would tear and become unusable.

(Problems that the invention attempts to solve) This invention solves these conventional problems,
This was completed in order to provide an air diffuser whose membrane will not be damaged even if the amount of ventilation exceeds a certain value for some reason.

(Means for solving the problem) The first idea made to solve the above problem is that one end is closed and the other end is connected to a small diameter pipe for supplying air, and an appropriate number of pipes are installed on the circumference. An elastic cylindrical membrane with countless slits is placed around the outer periphery of a pipe-shaped holder with air injection holes.
The device is characterized in that a cylindrical net-like or spiral expansion regulating member is provided along the entire outer periphery along the shape of the membrane, and is fixed to both ends of the pipe-like holder using ring-like fixtures.

A second idea for solving the above problem is to create a pipe-like structure in which one end is closed, the other end is connected to a small diameter pipe for supplying air, and an appropriate number of air injection holes are formed on the circumference. An elastic cylindrical membrane with countless slits is placed around the outer circumference of the holder.
This membrane is characterized by being fixed to a pipe-shaped holder at a plurality of locations, including at least both ends and the center, using ring-shaped fixtures that follow the shape of the membrane.

(Examples) Next, the present invention will be explained in more detail with reference to illustrated examples.

In FIG. 1, 1 is a pipe-shaped holder whose one end is closed and the other end is connected to a small diameter pipe 2 for supplying air, and 3 is a header pipe. A suitable number of air ejection holes 4 are formed on the circumferential surface of the pipe-shaped holder 1 as shown in the figure. The diameter of the air jet holes 4 may be approximately 1/3 of the inner diameter of the holder, and the number thereof may be approximately 5 per 10 cm.

Reference numeral 5 denotes a cylindrical membrane made of an elastic material such as rubber that is stretched around the outer periphery of the pipe-shaped holder 1, and countless slits are formed in this membrane 5 to diffuse air through these slits. The structure allows for In this embodiment, a cylindrical mesh-shaped expansion regulating member 6 is installed along the entire outer periphery of the cylindrical membrane 5 at a slight distance from the membrane 5 and along the shape of the membrane 5.
The expansion regulating member 6 is fixed to both ends of the pipe-shaped holder 1 by ring-shaped fixtures 7. Note that the opening of the net-like expansion regulating member 6 differs depending on the elastic limit of the membrane 5, but when a rubber membrane is used,
~10 times, preferably about 5 times. If the opening is too small, bubbles will be combined in the expansion regulating member 6, resulting in a large bubble diameter and a decrease in oxygen transfer efficiency. Furthermore, if the opening is too large, the effect of preventing the membrane 5 from expanding will be reduced. Furthermore, it is preferable to insert reinforcing wires into the net at appropriate pitches.

In the embodiment shown in FIG. 2, a spiral rigid wire is used as the expansion regulating member 6. In this case as well, the pitch between the rigid wires is preferably 2 to 10 times the pitch of the slits in the membrane 5.

In the embodiment shown in FIG. 3, the expansion regulating member 6 having the structure shown in FIG. 1 is fixed to the pipe-shaped holder 1 not only at both ends but also at the center by ring-shaped fixtures 7.

In the air diffuser of the first invention described above, if pressurized air is supplied into the pipe-shaped holder 1 through the small-diameter pipe 2, the pressurized air enters the back surface of the cylindrical membrane 5 from the air jet hole 4. , air is diffused through the slit while pushing the membrane 5 outward. Since the entire outer periphery of the cylindrical membrane 5 is covered with a cylindrical mesh-like or spiral expansion regulating member 6 that follows the shape of the membrane 5, if the ventilation rate becomes excessive for some reason, Even if the membrane 5 tries to expand rapidly, it is suppressed by the expansion regulating member 6, and the ventilation resistance increases rapidly to prevent ventilation beyond a certain value. Therefore, an accident in which the slit of the membrane 5 is torn can be prevented.

FIG. 4 shows an embodiment of the second invention, which has a structure in which the expansion regulating member 6 is omitted from the embodiment shown in FIG. That is, in this embodiment, a plurality of ring-shaped fixtures 7 that conform to the shape of the cylindrical membrane 5 are used to fix the membrane 5 to the pipe-shaped holder 1 at a plurality of locations including at least both ends and the center. These small spaced fixtures 7 prevent the expansion of the membrane 5.
This is to prevent this. Note that the interval between the fixtures 7 is preferably about 250 to 300 mm.

In addition, in any of the embodiments shown in FIGS. 1 to 4, when the ventilation is stopped, the membrane 5 is compressed by water pressure, and the slit closes to prevent water from entering inside. can.

(Effects of the invention) As explained above, the present invention uses a cylindrical mesh-like or spiral expansion regulating member provided along the outer periphery of a cylindrical membrane, or a plurality of ring-shaped fixing devices. Therefore, the expansion of the membrane can be regulated, and damage to the membrane can be reliably prevented even if the amount of ventilation increases for some reason. Moreover, the effect of preventing backflow when the ventilation is stopped is maintained in the same manner as in the conventional system, and there is no problem in operation at a normal ventilation rate.

Therefore, the present invention has extremely great practical value as an air diffuser that eliminates the problems of the conventional technology.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing an embodiment of the first invention, Figs. 2 and 3 are partially cutaway perspective views showing other embodiments, and Fig. 4 is an embodiment of the second invention. FIG. 5 is a partially cutaway perspective view showing a conventional example. 1...Pipe-shaped holder, 2...Small diameter pipe, 4
... Air blowout hole, 5 ... Cylindrical membrane, 6 ... Cylindrical mesh-like or spiral expansion regulating member, 7 ... Ring-shaped fixing device.

Claims (1)

[Claims for Utility Model Registration] 1. On the outer periphery of a pipe-shaped holder 1, one end of which is closed and the other end is connected to a small diameter pipe 2 for supplying air, and an appropriate number of air jet holes 4 are formed on the periphery. , an elastic cylindrical membrane 5 with countless slits is stretched, a cylindrical mesh-like or spiral expansion regulating member 6 is provided along the entire outer periphery along the shape of this membrane 5, and this is fixed as a ring-shaped fixture. 7 is fixed to both ends of a pipe-shaped holder 1. 2. The air diffuser according to claim 1, wherein the expansion regulating member 6 is also fixed to the center of the pipe-shaped holder 1. 3 An elastic tube having numerous slits on the outer periphery of the pipe-shaped holder 1, which has one end closed and the other end connected to a small-diameter pipe 2 for air supply, and has an appropriate number of air ejection holes 4 formed on its periphery. A pipe-shaped holder 1 is attached to the pipe-shaped holder 1 by a ring-shaped fixture 7 that stretches a certain cylindrical membrane 5 and aligns the shape of the membrane 5 at multiple locations including at least both ends and the center of the membrane 5.
An air diffuser characterized by being fixed to.