JPH0780486A - Control valve for small volume of air - Google Patents

Abstract

PURPOSE:To stably branch and supply the very small volume of air over a long period and to easily and accurately control the volume of air by providing a valve body with circular small holes the number of which is increased successively from one to an integral multiple at every interval correspondent to the inside diameter of the opening of an outlet pipeline. CONSTITUTION:Air branched from air used for aeration flows into a controlling valve 20 for the volume of air through an inlet pipeline 28 and passes through the circular small holes 23, 23a of a valve body 22 and thereafter flows out from an outlet pipeline 29. By the way, the valve body 22 is opened, closed and operated through a valve rod 27 by a handle 25. In the case, the number of the circular small holes 23a is increased successively from one to an integral multiple at every interval correspondent to the inside diameter of the opening 29a of the outlet pipeline 29. The volume of air is controlled by altering the number of the circular small holes 23a which appear in the opening 29a of the outlet pipeline 29 by means of rotation or sliding. thereby the very slight volume of air is stably branched and supplied over a long period and also the volume of air is controlled easily and accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-scale sewage purification apparatus, and more particularly to a valve for branching a small amount of air from aeration air in a sewage purification tank.

[0002]

2. Description of the Related Art In a small-scale sewage purification tank, pressured air is required for aeration, backwashing, temporary high-volume air lift, and minute circulation air lift. FIG. 5 is a system diagram of compressed air when the number of blowers 14 is one. Each application will be described based on FIG.

Aeration air is used as air diffuser when purifying wastewater by aerobic treatment. Although there is an exception to the intermittent aeration method, it is usually continuous aeration for 24 hours. Therefore,
The gate valve 13A is normally open.

Backwashing air is used as an operation for aerating air from below the contact filter medium to forcibly peel off the thickened biofilm. In the aerobic treatment of small-scale wastewater septic tanks, which mainly employ the contact aeration method, the biofilm thickens on the contact filter medium during long-term operation, so it is necessary once every several months.
Normally, aeration air is primarily diverted by a switching valve. Therefore, the sluice valve 13B is opened only when backwashing, and the sluice valve 13B is closed at other times.

The air for a large amount of temporary air lift is used as an operation for transferring the biofilm separated by the backwashing of the contact filter medium to the sludge storage section by an air lift pump. Air for aeration is diverted primarily by the switching valve. Therefore, the sluice valve 13C is opened only when sludge is returned, and the sluice valve 13C is closed at other times.

The micro air circulation air lift is used to constantly transfer and circulate the contact aeration tank water containing the biofilm naturally separated from the contact filter medium at a minute flow rate to the anaerobic filter tank. At the same time as the purpose of removing the biofilm that was naturally peeled from the contact aeration tank, the denitrification reaction was carried out by transferring and circulating the aeration tank water that was oxidized and nitrified ammonia nitrogen contained in the wastewater to the anaerobic filter bed tank. The purpose is to wake it up.

For this purpose, a dedicated air lift circulation pump is used to pump and circulate water at a very small flow rate.
The air from the blower 14 may also be used. In this case, the gate valve 13D is required.

However, usually, a large amount of air for air lift is temporarily squeezed into a small amount by the control valve 13C and used.

Needless to say, if the branch valve 13A,
If 13B, 13C, and 13D are not used, a blower for each purpose such as aeration and backwash is required, which complicates the piping structure inside the septic tank and increases the number of blowers, resulting in higher cost. In addition, there is a risk that the blower will be connected incorrectly during enforcement. Also, as the number of blowers increases, the cost of electricity and maintenance of blowers increase. Therefore, conventionally, a branch valve is often used in one blower as shown in FIG.

Next, the necessity of the small amount of circulating air lift air will be described more specifically.

When a small amount of the air lift pump is continuously operated, it is effective in removing nitrogen, removing suspended solids, stabilizing load fluctuations in the contact aeration tank, and preventing odor generation from the anaerobic filter tank. That is, (a) removal of nitrogen When a small amount of nitrogen (NO _x -N) nitrified in the contact aeration tank is returned to the previous stage of the contact aeration tank (for example, the first chamber of the anaerobic filter bed tank) (continuous circulation), Nitrogen removal can be obtained by the anaerobic condition without dissolved oxygen, which is the condition of nitrification, that is, anoxic condition, and the presence of an organic substance (carbon source) obtained as hydrogen donor from raw water. If the contact aeration tank is not equipped with an air lift pump, or if it is installed and is not operated, the nitrogen nitrified in the contact aeration tank is NO _x −.
It exists in the form of N, and the nitrogen in the raw water only changes its form, and is lost to the outside of the septic tank.

(B) Removal of Suspended Substances When sludge (suspended substances) generated in the contact aeration tank or sludge (also called biofilm) attached to the contact material is naturally peeled off,
If these sludges are stored here by promptly transferring them to the first chamber of the anaerobic filter tank which is the preceding stage of the septic tank,
It is possible to prevent the floating separated sludge from flowing out of the septic tank. At this time, the peeled sludge is transferred at a small flow rate so as not to disturb the inside of the anaerobic filter tank.

Incidentally, when sludge adhered to the contact material of the contact aeration tank is forcibly separated by backwashing, the separated sludge can also be transferred to the anaerobic filter first chamber by continuous operation of the air lift. However, it is impossible to remove all the sludge that has settled in the contact aeration tank without continuous operation of the air lift pump, and in continuous operation, the air lift amount must be reduced as described above. .

Although the contact aeration tank is equipped with an air lift pump, this adjustment is difficult in the case of a septic tank without a branch control valve for air lift circulation.

(C) Stabilization of load fluctuations in the contact aeration tank By continuously circulating a small amount of water treated in the contact aeration tank with an air lift pump, a source of organic matter is continuously supplied to microorganisms adhering to the contact material. It can be supplied, the activation of microorganisms is enhanced, and the processing function is improved.

By continuously circulating a small amount of water treated in the contact aeration tank to the first chamber of the anaerobic filter bed tank in the preceding stage of the purification tank, a diluting effect of the organic matter concentration can be obtained and the load applied to the contact aeration tank can be reduced. It also stabilizes during peak drainage inflow.

That is, in the small-scale sewage purification tank, organic matter is supplied to the contact aeration tank when there is drainage, and the amount of the organic matter greatly fluctuates depending on the amount of drainage water, and the load on the contact aeration tank fluctuates significantly.

When the load changes drastically, the load of organic matter on the contact aeration tank becomes unstable, and the dissolved oxygen in the contact aeration tank decreases significantly during the time when the amount of discharged water is large, and the treatment function cannot be supported and the purification cannot be performed. There is a nature. Therefore, a small amount of continuous circulation is necessary to stabilize the processing function.

(D) Prevention of Odor Generation from Anaerobic Filter Tank By circulating the contact aeration tank water containing dissolved oxygen, it is possible to prevent anaerobic decay in the anaerobic filter tank and prevent odor generation.

[0020]

In a small-scale sewage purification apparatus such as a domestic septic tank, air lift circulation is often performed. In this case, aeration air is branched and used to be squeezed to a very small amount, but intermittently. When the air lift for operation is also used, the aeration air pressure fluctuates.
Adjust the flow rate with the branch valve before use.

In other words, in a small-scale sewage purification tank, when a small amount of air is branched from the aeration air amount and released to adjust the aeration amount, or when it is used for other purposes such as air lift circulation. The adjustment of the branch amount is usually performed by valve adjustment.

A ball valve, a sluice valve, a cock (including a ball cock), etc. are used for this valve, but when narrowing down to a micro sectional area, it is necessary to adjust with a very narrow and narrow slit type or a crescent shaped section. Become. For example, FIGS.
In the conventional control valve of No. 6, only the portion 67 where the closing circle 63 of the valve body 62 and the opening circle 64 of the outlet pipe 60 in FIG.

More specifically, FIG. 6 is a central longitudinal view of a typical sluice valve of a conventional control valve, and FIG. 7 is a valve body closing action diagram. A valve body 62 is provided at the center of the valve box 61.
When the handle 65 is rotated, the valve body 62 of FIG. 6 moves to the portion of the opening circle 64 of the outlet pipe 60. Therefore, only the portion 67 where the valve body 62 and the opening circle 64 do not overlap is a cross section through which air can pass. Since the area of the valve body 62 and the opening circle 64 where the opening circle 64 does not overlap is large, the cross-sectional area of the portion 67 where the valve body 62 does not overlap changes significantly even if the knob adjustment of the handle 65 is slight, and a minute flow rate adjustment is performed. It is difficult. Furthermore, since a fine and narrow passage area also clogs dust, it was not possible to stably maintain the adjustment passage area for a long time.

As described above with reference to FIGS. 6 and 7, when the conventional branch valve is used for continuous operation of the air lift pump, the amount of air sent for air lift circulation tends to decrease or stop for a short time. The stability was poor, and the effect on the function was large.

Further, since the amount of air required for air lift circulation is in a very small range, it is difficult for the conventional branch valve to set and adjust the required amount of air, and the rough amount of air is set. Next, it had a great effect on the function.

The present invention relates to a small-scale sewage purification tank,
By improving the valve body, it is possible to stably branch a small amount of air from aeration air as air for air lift circulation etc. for a long period of time, and to provide a control valve capable of stable flow rate adjustment. And

[0027]

In order to achieve the above object, the minute air flow control valve according to the present invention is provided with an outlet pipe for branching a small amount of air from the aeration air of a small-scale wastewater septic tank to the outlet pipe. The opening provided in the valve body so as to communicate with the. One circular eyelet has the minimum required opening area. The number of the circular small holes is sequentially increased from 1 to an integer multiple at intervals corresponding to the inner diameter of the outlet pipe opening. The opening area is adjusted by changing the number of circular small holes appearing in the opening of the outlet pipe by rotating or sliding. By adjusting the opening area, the present invention provides a valve for adjusting a minute amount of the branched air.

The small hole provided in the valve body is preferably circular, but it does not have to be circular.

[0029]

[Function] In the anaerobic filter contact aeration method, which is a typical treatment method of the combined treatment septic tank, the nitrification (NO
_x- N) is cycled. As a result, once nitrified nitrate nitrogen is denitrified in the anaerobic tank, and when denitrification proceeds, the alkalinity is increased and this is supplied to the aerobic tank, so that the pH of the aerobic tank is neutralized, and more The activity of nitrifying bacteria is increased. Further, the nitrification rate is improved by increasing the frequency of contact between the biofilm and the substrate due to the increase in the amount of airlift circulating water.

As described above, since it is important that the flow rate is constant in order to improve the efficiency of biological nitrification / denitrification, the minute amount of air used for air lift circulation is also constant. It is necessary to squeeze and branch. This is made possible by the present invention, and since it was difficult to squeeze and branch a minute amount of air with a conventional globe valve, sluice valve, cock, etc., it is difficult to obtain the present invention. It can be said to bring about a remarkable effect.

Assuming that the shape of the minimum necessary circular opening small hole is a safety diameter of 1.0 m / mφ that does not clog with dust etc., the branching ratio is 1/1 when the minimum aeration pipe is 13 m / mφ.
It becomes 69, and a minute amount of air can be branched.

The air branching amount is adjusted by changing the scale position by operating the handle to increase or decrease the number of circular small holes, and the adjusting amount is an integral multiple of the flow rate of one small hole.

If the air pressure for aeration is constant, the air branch amount can be grasped by the number of circular small holes.

When air lift circulation or the like is smoothly performed by the air flow control valve of the present invention, contact aeration tank water containing dissolved oxygen is circulated, and it can be expected to prevent odor generation in the anaerobic filter bed tank.

[0035]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a central longitudinal sectional view of a minute air volume control valve according to an embodiment of the present invention. FIG. 2 is a plan view of the air volume control valve according to the embodiment of FIG.

The air flow control valve comprises a valve box 21, a valve body 22, a handle 25, and a valve rod 27, and the valve body 22 has a circular small hole 23. The air flow control valve 20 is arranged between the inlet pipe 28 and the outlet pipe 29.

In FIG. 3, the valve body 22 is expanded and a circular small hole 23 is formed.
It is a figure which shows the open state of. Circular small hole 23 is outlet pipe 2
When it overlaps with the opening 29a of 9, the air volume corresponding to the number of the circular small holes 23 flows out. Except for the circular small holes 23, the outlet pipe 29 and the inlet pipe 28 are blocked by the sheet packing 30.

A scale plate 26 is provided on the lid 24 of the valve box 21. At the steering wheel position 0, it is fully closed. At the handle position 1, one circular small hole 23a is opened. At the handle position 2, two circular small holes 23a and 23b are opened.
The number of circular small holes opened increases as the handle position changes. In addition, the rotation of the handle 25 is performed by the O-ring 31.
At the same time as it is sealed by the vibration, there is no displacement due to vibration.

Next, the operation of the control valve will be described.

When the handle 25 is fitted to the position of the scale plate 0 in FIG. 2, the valve body is fully closed, and the handle 0 in the developed view of FIG.
Position.

When the handle 25 shown in FIG. 2 is aligned with the scale plate 1 for air lift circulation, the handle 25 is at the handle position 1 in the exploded view of the valve body shown in FIG.
One 3a appears in the opening 29a of the outlet pipe 29.

FIG. 1 shows a central longitudinal sectional view of the control valve 20 in which one circular small hole 23a of the valve body 22 is opened.

The air branched from the aeration air enters the control valve 22 from the inlet pipe 28 at the bottom of the control valve 22 of FIG. 1, passes through the circular small hole 23a of the valve body 22, and the air lift circulation outlet pipe 29. Enter and circulate.

In the examples of the present invention, the diameter of the inlet and outlet pipes was 13 m / mφ, and the diameter of the circular small holes was 1 m / mφ.

Although the amount of branched air was small, the flow rate was constant, and stable air lift circulation could be performed for a long period of time.

Further, unlike the conventional open state of the valve body having a crescent-shaped cross section, dust was not clogged even in the circular small hole having a diameter of 0.7 mm.

When the branch control valve was installed in the middle of the straight pipe, the same purpose could be achieved by using the control valve shown in FIG. The main components are shown by the same numbers as in FIG. 1 and their explanation is omitted.
The flow of wind is indicated by arrows.

Although the valve element rotates in the above embodiment,
The small holes may be slidably moved.

[0050]

Since the present invention employs the configuration described above, the following effects are produced.

(1) In the control valve, the circular small hole has a minimum safety dimension that does not cause clogging with dust or the like, so that the air amount can be stably branched for a long period of time.

(2) Since the shape of the circular eyelet can be reduced,
It can stably branch a small amount of air.

(3) The amount of branched air is adjusted by increasing or decreasing the number of circular small holes, and the amount of adjustment is an integral multiple of the flow rate of one small hole. Further, the handle of the valve can be easily operated only by adjusting the scale position.

(4) If the pressure of the aerated air is constant, the amount of branched air can be determined by the number of circular small holes used.

(5) The orifice type air flow control valve allows stable air lift circulation for a long period of time.

(6) In a small-scale sewage purification tank, the efficiency of sewage treatment is improved, and a high quality of water can be obtained stably for a long period of time.

(7) By circulating the contact aeration tank water containing dissolved oxygen, it is possible to prevent anaerobic spoilage in the anaerobic filter bed tank and prevent odor generation.

[Brief description of drawings]

FIG. 1 is a central vertical cross-sectional view of a minute air volume control valve according to an embodiment of the present invention.

FIG. 2 is a plan view of the minute air volume control valve according to the embodiment of FIG.

FIG. 3 is a development view of a cylindrical portion of a valve body.

FIG. 4 is a central longitudinal sectional view of an embodiment of the present invention of a minute air volume control valve attached to a straight pipe portion.

FIG. 5 is a system diagram of a valve that branches air from aeration air.

FIG. 6 is a central longitudinal cross-sectional view of a conventional valve.

FIG. 7 is a view showing a conventional valve body aperture adjusting action.

[Explanation of Codes] 20 Micro Air Volume Control Valve 21 Valve Box 22 Valve Body 23, 23a, 23b Circular Small Hole 24 Valve Lid 25 Handle 26 Scale Plate 27 Valve Rod 28 Inlet Piping 29 Outlet Piping 29a Outlet Piping Opening 30 Seat Parking 31 O Rings 13A, 13B, 13C Gate valve 63 Valve body 64 Outlet piping opening 67 Opening part where two circles do not overlap

Claims (1)

[Claims] 1. An air flow control valve device for branching a small amount of air from an aeration air of a small-scale sewage purification tank to an outlet pipe,
A valve body provided with circular small holes having a minimum required cross-sectional area, wherein the number of the circular small holes is sequentially increased from 1 to an integer multiple for each interval corresponding to the inner diameter of the outlet pipe opening. A minute air flow control valve which is provided and which controls the flow rate by changing the number of the circular small holes appearing at the opening of the outlet pipe by rotating or sliding, and the valve body also includes the adjustment of fully closed and fully opened.