JPS649043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a gas-liquid mixing device that mixes gas in a liquid and aerates the mixture.

(Prior art) Generally, when dissolving and moving gas into a liquid and stirring and mixing it in a liquid tank, the air blowing method using a blower or stirring aeration of the surface of the liquid using a stirrer is generally used. There are a surface mechanical aeration method and a liquid circulation method using a pump performed by the gas-liquid mixing device of the present invention.

In conventional liquid circulation methods using pumps, a tightening device such as an ejector is installed in the route or at the end of the pipe to reduce static pressure and suck gas into the pipe, causing shearing of the gas within the pipe. In most cases, the liquid is made fine and a gas-liquid multiphase flow is formed, and this is injected into the liquid or onto the liquid surface and circulated.
In such a device, there is a large amount of energy loss such as friction loss within the pipe, and the power per unit weight of dissolved gas is usually excessive, resulting in low power efficiency.

In addition, a liquid column that is injected or falls through the gas that is released towards the liquid surface may be caused by entrainment of gas due to turbulence on the surface of the liquid column, entrainment of gas in the gas-liquid boundary layer of the liquid column, or It is a natural state that the gas surrounding this injected liquid column is entrained and supplied into the liquid due to the entrainment of gas due to the turbulence of the liquid surface when it penetrates into the liquid surface, and stirring and gas-liquid mixing occur. However, in this case, the mixing area is often limited to the upper part of the liquid tank, and gas dissolution efficiency is usually low.

Furthermore, in the past, an ejector or the like was used to create an unnecessarily high pressure inside the pipe to create a gas-liquid multiphase flow within the pipe and generate microbubbles; Even if the dissolution efficiency of the gas in the tank is high, it is localized, and overall it only creates conditions for poor dissolution efficiency, which is a waste of energy from the original purpose.

In addition, the aeration device shown in Japanese Patent Publication No. 50-3021 inserts a liquid supply nozzle and the lower end of the air supply pipe around the outer periphery of this nozzle into the liquid in the liquid tank body, and then A mixing pipe is provided below from the outer periphery of the lower end of the air supply pipe, but this performs gas-liquid mixing only below the liquid surface, and the jet liquid column discharged from the liquid supply nozzle An effective gas suction effect cannot be obtained.

Furthermore, the sewage purification device shown in Japanese Patent Publication No. 47-13958 has an air intake that expands upward in the upper part of the water pipe whose lower part is inserted into the liquid in the aeration tank. The tip of the upper pipe that discharges the liquid is placed in the center of the pipe.According to this, the sprayed liquid column discharged from the upper pipe is guided by the water pipe and reaches deep into the liquid, but the injection Because the liquid column comes into contact with the water pipe, gas is entrained due to disturbance on the surface of the liquid column, gas is entrained in the liquid column due to viscosity at the gas-liquid interface, and the liquid level is affected when the liquid column penetrates into the liquid surface. The entrainment of gas due to turbulence is impaired.

In addition, as shown in Utility Model Application Publication No. 13698 of 1933, the lower part of the air injection cylinder is inserted deeply into the liquid in the liquid tank, and the water jet pipe is inserted into the upper part of this air injection cylinder. There is a liquid purifying device in which a portion of the air injection tube is narrowed to a small diameter around the tip of the water jet tube. However, in this liquid purifier, since the air injection tube is deeply submerged in the liquid, there is a relatively large resistance to the air flowing out through this submerged part, and the air is sucked into the air injection tube. The amount of air that gets caught up in the water jet also tends to be smaller. Also,
Since the air injection cylinder is deeply submerged in water, the dissolution of air into the liquid is mainly performed inside the air injection cylinder, and the mixing and agitation of air throughout the liquid tank is also limited by the air injection cylinder. Furthermore, the agitation in the liquid tank and the dissolution of air into the liquid are blocked by the air injection tube that is deeply submerged in the liquid, making it inefficient, which means that the energy efficiency of the liquid circulation system is poor. This means that the power efficiency of the liquid circulation system is low.

Furthermore, as shown in Japanese Utility Model Publication No. 48-35564, there is a pressure water injection type in which a nozzle is placed in the through hole of an annular float with a through hole in the center, with the lower end outlet slightly above the liquid level. There is an aeration system. This device supplies the air that has been taken into the aeration tank into the liquid, and the through hole provided in the float is for attaching a nozzle. Fresh air is not taken in from outside the aeration tank. Then, the air in the tank is entrained into the wastewater by the action of the nozzle, so the air that has been used and has a reduced oxygen concentration is reused.
Since the oxygen is supplied into the wastewater, the amount of oxygen transferred into the wastewater decreases, resulting in poor oxygen transfer efficiency. Furthermore, since the distance between the nozzle tip and the dirty water surface is small, no jetted liquid column is formed at the nozzle tip. Therefore, the amount of air entrained in the wastewater is small, and from this point of view, the amount of oxygen transferred is also reduced. Therefore, it can be said that this float type device has poor energy efficiency and is energy consuming.

(Problems to be Solved by the Invention) As described above, the conventional apparatus has the problems of low power efficiency and low efficiency of gas dissolution and transfer into liquid.

The present invention was made in view of these points,
The object of the present invention is to provide a gas-liquid mixing device with a simple structure that can reduce the power required in a liquid circulation method using a pump, increase power efficiency, and increase the efficiency of gas dissolution and transfer into liquid. .

[Structure of the invention]

(Means for Solving the Problems) The gas-liquid mixing device of the present invention has a liquid suction pipe 5 drawn out from the liquid tank main body 2, a pump 6 connected to the liquid suction pipe 5, and a liquid suction pipe 5 connected to the liquid suction pipe 5. A liquid supply pipe 10 connected to the discharge part is disposed above the liquid tank main body 2, and a tip of the liquid supply pipe 10 is provided with a pipe that gradually constricts toward the liquid level 11 inside the liquid tank main body 2. The speed increaser tube nozzle 12 is connected, and a certain distance is provided between the tip of the speed increaser tube nozzle 12 and the liquid level 11, and the liquid from the speed increaser tube nozzle 12 is connected to the tip of the speed increaser tube nozzle 12. Forming a sprayed liquid column 13 that is sprayed onto the surface 11 and accelerated by gravity to fall, the entire length of the nozzle 12 and the outer periphery of this sprayed liquid column 13 does not come into contact with the sprayed liquid column 13 through a gap 14. A cover tube 15 having a straight shape with a constant diameter and an open bottom end is disposed in an elongated manner from the outside to the inside of the liquid tank body 2.
5 is immersed below the liquid surface, and a gas suction port 17 is provided at the upper part of the cover tube 15 that protrudes to the outside of the liquid tank body 2, and the gas is entrained by the sprayed liquid column 13, and the gas is entrained in the liquid. A vertical gas-liquid multiphase flow is formed to perform gas-liquid mixing and gas dissolution and movement into the liquid.

(Function) In the present invention, when liquid is injected from the tip of the speed increasing tube nozzle 12, the negative pressure generated around the injected liquid column 13 causes the gas suction port 17 outside the liquid tank body 2 to
Fresh gas is always sucked into the cover tube 15 from the inside of the cover tube 15, and the gas is drawn into the sprayed liquid column 13 and plunged into the liquid together with the sprayed liquid column 13.
The liquid is immediately diffused into the liquid tank main body 2 from the opening at the tip thereof, mixed and stirred throughout the tank, and is dissolved in the liquid. Gas that is not dissolved in the liquid is released onto the liquid surface, but this used gas does not enter the interior of the cover tube 15 and is not reused.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

A collision plate 3 is provided at the bottom of a liquid tank main body 2 having a ventilation pipe 1 provided at the top, and a liquid suction pipe 5 having a liquid suction port 4 is inserted downward into the liquid tank main body 2 at the lower side of the collision plate 3. A liquid suction section 7 of a pump 6 fixedly installed outside is connected to this liquid suction pipe 5, and a liquid supply pipe 10 is connected to a liquid discharge section 8 of this pump 6 via a valve 9.

This liquid supply pipe 10 is disposed up to the upper part of the center of the liquid tank main body 2, and the distal end of the liquid supply pipe 10 is provided with an intensifier that gradually contracts toward the liquid level 11 inside the liquid tank main body 2. While connecting the fast pipe nozzle 12 vertically,
A certain distance is provided between the tip of the speed increasing tube nozzle 12 and the liquid level 11.

Further, at the tip of the speed increaser tube nozzle 12, an injected liquid column 13 is formed which is injected from the speed increaser tube nozzle 12 onto the liquid surface 11 and falls by gravity.
2 and the outer periphery of this injection liquid column 13, a void 14 is formed.
A straight cover pipe 15 with a constant diameter over its entire length and an open bottom end that does not come into contact with the sprayed liquid column 13 through the liquid tank 2 is disposed in an elongated manner from the outside to the inside of the entire liquid tank 2, This cover tube 15
Only the tip of the lower end of is immersed below the liquid level 11.
The upper end of this cover tube 15 is closed by a cover plate 16, and the cover tube 1 protrudes outside the liquid tank body 2.
A gas suction port 17 is provided on the upper side surface of 5, and a gas suction pipe 18 is provided in this gas suction port 17.

Next, the operation of this embodiment will be explained.

The liquid in the liquid tank main body 2 is guided by a pump 6 through a liquid suction pipe 5 to a speed increasing tube nozzle 12 installed at the upper part of the liquid tank main body 2, and at the outlet of this nozzle 12, the speed is 2 to 5 m/sec. The flow rate is increased to . Since the speed increasing tube nozzle 12 is gradually constricted, there is little loss due to liquid flow separation, vortex flow, etc., and more than 98% of the energy is converted into velocity energy.

Then, the jetted liquid column 13 formed by being jetted from the tip of the speed increasing tube nozzle 12 converts the potential energy at the nozzle exit into velocity energy, and encloses gas inside the cover tube 15 while increasing the falling speed. It is entrained and penetrates the liquid level 11 without losing much of its energy. The liquid flow that has penetrated the liquid surface 11 is suppressed from dispersing in the horizontal direction by the cover tube 15 that is slightly immersed in the liquid, and becomes a vertical flow, penetrating deeply into the liquid and causing gas shear in the liquid. As it occurs, it becomes a vertical gas-liquid multiphase flow, and the gas dissolves and moves into the liquid and mixes with it.

Furthermore, the gas-liquid multiphase flow hits the collision plate 3 and is converted into an upward flow, thereby increasing the mixing performance and preventing gas from entering the liquid suction pipe 4. The liquid is repeatedly pumped by the pump 6. It is circulated.

In such liquid circulation by the pump 6, the gas in the gap 14 is entrained into the liquid by the injection liquid column 13 injected from the speed increaser tube nozzle 12 inside the cover tube 15. The pressure decreases, and the cover tube 15 self-inhales new gas from the outside via the gas suction tube 18.

According to the actual example, the intake air amount Vg is basically:
It is correlated with the amount of circulating fluid Q, the diameter of the tip of the speed increasing tube nozzle 12, and the falling height, and it is possible to easily set Vg/Q to 1 or more when the diameter of the tip is in the range of 20 to 200 mm.

Furthermore, the dissolution and movement characteristics of gas into the liquid by this device are less affected by the amount of gas self-suctioned into the cover tube 15, and the amount of gas dissolution and movement into the liquid in the liquid tank body 2 is small. The range of change is small. In other words, when the same energy is used and the amount of self-suctioned gas is small, the gas dissolution transfer efficiency (the weight ratio of the gas dissolved and transferred into the liquid and the self-suctioned gas) increases, and the amount of self-suctioned gas increases. If is large, the dissolution and transfer efficiency of the gas becomes small, and the change in the value of the amount of gas dissolution and transfer into the liquid is small. This means that when the gas is a harmful gas and requires equipment for removal, deodorization, etc., self-suction can be supplied into the cover pipe 15 without reducing the power efficiency for dissolving and moving the gas into the liquid. This also means that the amount of gas released can be reduced.

〔Effect of the invention〕

According to the present invention, the speed increasing tube nozzle, which is gradually contracted toward the liquid level inside the liquid tank body, is connected to the tip of the liquid supply tube, and the tip of the speed increasing tube nozzle and the A fixed interval is provided between the speed increaser tube nozzle and the speed increaser tube nozzle, and the jet liquid column is irradiated onto the liquid surface from the speed increaser tube nozzle and falls by gravity. A cover tube with an open bottom end is provided, the lower part of this cover tube is immersed below the liquid level, and a gas suction port is provided at the upper part of the cover tube, so it can not be moved inside the pipe like a conventional ejector. Rather than performing gas-liquid mixing, it is possible to effectively perform a self-priming action similar to that of an ejector using a column of injected liquid in the space above the liquid surface, and unlike conventional ejectors, there is little reduction in power efficiency. In other words, since the gas-liquid multiphase flow is generated in the liquid in the liquid tank body rather than in the pipes, friction loss in the pipes is extremely small, and most of the energy can penetrate into the liquid, allowing stirring and mixing and gas The power efficiency for dissolving and moving into the liquid is increased.

Further, according to the present invention, in the cover pipe where a self-priming action similar to that of the ejector is performed, at the same time, the injected liquid column injected from the speed increaser pipe nozzle is caused to entrain gas due to surface turbulence, and to This causes entrainment of gas due to the viscosity of the liquid, and entrainment of gas due to turbulence of the liquid surface when penetrating into the liquid. Since the gas is unified into one without being dispersed in the direction, the penetration depth into the liquid in the liquid tank body is greatly increased, forming a deep vertical gas-liquid multiphase flow in the liquid, and the gas is entrained. The gas is finely divided by the shear force with the liquid, increasing the gas-liquid contact area and increasing the efficiency of gas dissolution and transfer into the liquid. in this way,
Generating a gas-liquid multiphase flow in the liquid in the liquid tank body allows the gas to freely and constantly contact the unmixed liquid with a high concentration difference, which is one of the reasons for increasing the gas dissolution efficiency. ing.

Furthermore, in the present invention, since the tip of the cover tube is only slightly submerged below the liquid surface, compared to a case where the cover tube is submerged deeply below the water surface, the water flows out through the submerged portion. The resistance to gas is relatively small, and therefore a sufficient flow rate of gas can be drawn into the injected liquid column without the need to aim for a strong ejector effect by providing a restrictor in the cover tube. In addition, since the tip of the cover tube is slightly submerged below the liquid level, the gas trapped in the sprayed liquid column becomes bubbles and immediately diffuses into the tank body from the opening at the tip of the cover tube, causing Since the entire liquid is mixed and stirred, a large amount of gas is dissolved in the liquid. Therefore, when looking at the movement of gas into the liquid, assuming the performance of the liquid circulation system such as the circulation pump is the same, the amount of energy required to dissolve a certain amount of gas in the liquid is relatively small. , the energy efficiency of the liquid circulation system is good. This can also be said to have high power efficiency for the liquid circulation system.

Further, the gas-liquid mixing device of the present invention is provided with a cover pipe extending from the outside to the inside of the liquid tank main body, and further,
Since the tip of the cover tube is immersed in the liquid surface, fresh gas from outside the tank is constantly supplied directly into the liquid together with the injected liquid column through the cover tube. For this reason,
When air is used, treated water with a constant oxygen concentration can be supplied, and a large amount of oxygen is transferred into the liquid. Furthermore, even if the gas dispersed in the liquid rises from the cover tube and is dispersed onto the liquid surface, this oxygen-poor gas will not enter the cover tube again. In addition, because a certain distance was provided between the tip of the speed increaser tube nozzle and the liquid surface, and the injection liquid pressure was created at the tip of the speed increaser tube, the amount of gas entrained by this injection liquid column was large, and the liquid The amount of oxygen transferred into the interior is large. In this way, the gas-liquid mixing device of the present invention takes in fresh gas through the cover pipe,
The entrainment of gas by the irradiated liquid column has the effect of increasing the amount of gas dissolved in the liquid, so the amount of gas transferred per unit of energy is large, making it an energy-saving device.

[Brief explanation of drawings]

The drawing is a sectional view showing an embodiment of the gas-liquid mixing device of the present invention. 2...Liquid tank body, 5...Liquid suction pipe, 6...Pump, 10...Liquid supply pipe, 11...Liquid level, 12...
... Speed increaser tube nozzle, 13 ... Injected liquid column, 14 ... Gap, 15 ... Cover pipe, 17 ... Gas suction port.

Claims (1)

[Claims] 1 Pull out the liquid suction pipe from the liquid tank body to the outside, connect a pump to this liquid suction pipe, arrange the liquid supply pipe connected to the liquid discharge part of this pump to the top of the liquid tank body, and connect this liquid supply pipe to the top of the liquid tank body. A speed increasing tube nozzle, which is gradually contracted toward the liquid level inside the liquid tank body, is connected to the tip of the speed increasing tube nozzle, and a certain distance is maintained between the tip of the speed increasing tube nozzle and the liquid surface. is provided at the tip of the speed increasing tube nozzle to form a jetted liquid column which is injected from the speed increasing tube nozzle onto the liquid surface and is accelerated by gravity and falls, and on the outer periphery of the speed increasing tube nozzle and this jetted liquid column, A straight cover pipe with a constant diameter over its entire length and an open bottom end that does not come into contact with the injected liquid column through a gap is arranged in an elongated manner from the outside of the liquid tank body to the inside. Only the bottom tip of the tank is immersed below the liquid surface, and a gas suction port is provided at the top of the cover tube that protrudes to the outside of the liquid tank body, and the gas is entrained by the jetted liquid column, creating a vertical gas-liquid mixed phase in the liquid. A gas-liquid mixing device characterized by forming a flow to perform gas-liquid mixing and gas dissolution and movement into the liquid.