JP5214341B2 - Gas seal device - Google Patents

Description

  The present invention relates to a gas seal device that can always keep a seal between inside and outside air while keeping a liquid level of a stored liquid constant, and is applicable to a stirring device in an anaerobic digestion tank.

  In recent years, in a sewage treatment plant, a method in which sludge is stirred and fermented in an anaerobic environment has been employed, and an anaerobic digestion tank has been employed to generate methane gas during the fermentation process. In other words, an anaerobic digestion tank is used in the sludge digestion process, but a screw or impeller for stirring the sludge is placed in the digestion tank and the screw or impeller is rotated. There is also a need for a stirring device having a structure in which a motor of the type is attached outside the digestion tank.

At this time, as the digestion tank is made an anaerobic tank, a combustible digestion gas mainly composed of methane gas generated by the sludge digestion process has an atmospheric pressure of, for example, about 200 mmAq to 300 mmAq. It is full while being raised. For this reason, as the rotating shaft of the motor penetrates the upper side wall of the digestion tank, a gas seal device using a liquid such as water for sealing between the inside and outside air is also required.
JP-A-8-10798 Japanese Patent Laid-Open No. 9-215916

However, when a gas seal device that uses a liquid such as water to seal the inside and outside of the digestion tank due to the presence of the stirring device is used, when the liquid is insufficient or disappears due to evaporation or the like, the gas seal is There was a risk that methane gas or the like in the digestion tank would leak into the outside air due to incompleteness.
In view of the above facts, an object of the present invention is to provide a gas seal device capable of always sealing a gas while keeping the liquid level of the stored liquid constant.

A gas seal device according to claim 1 includes a main body tank for storing a stirring target therein,
An agitation rotating shaft that penetrates the upper wall of the main body tank and rotates to agitate the object to be agitated;
A storage pot composed of a bottom surface and a cylindrical side wall, the center of the bottom surface being joined to the outer periphery of the rotating shaft ,
While being positioned above the reservoir pot is composed of a cylindrical side wall, a lower edge of the side walls of the bottom and clearance of the reservoir pot and the side wall of the storage pot side wall thereof with said rotary shaft An intermediate cylinder disposed between and having an upper portion of the side wall fixed to the upper wall of the main body tank;
A replenishment tank in which seal liquid is stored;
A proximal end side connected to the replenishing tank, a distal end side opened into the intermediate cylinder, and a liquid feed pipe capable of feeding the seal liquid into the intermediate cylinder,
Seal liquid is stored in the storage pot and the intermediate cylinder, a replenishment tank is disposed above the seal liquid surface in a sealed state with the inside isolated from the outside air, and the leading end side of the liquid supply pipe is in the intermediate cylinder Opened in the sealing liquid, the sealing liquid in the intermediate cylinder is stored to a height exceeding the opening position on the tip side of the liquid feeding pipe,
When the sealing liquid in the storage pot and the intermediate cylinder is reduced and the opening on the tip side of the liquid feeding pipe is exposed from the sealing liquid, the outside air enters the replenishing tank through the opening on the tip side of the liquid feeding pipe, An amount of sealing liquid that matches the amount of outside air that has entered the inside is supplied from the replenishing tank, and the sealing liquid is replenished into the intermediate cylinder to a height at which the opening on the tip side of the liquid feeding pipe is hidden in the sealing liquid. This is a gas seal device characterized by the above.

The operation of the gas seal device according to claim 1 will be described below.
According to the gas seal device of the present invention, the rotatable rotating shaft passes through the upper wall surface forming the upper portion of the main body tank, and has a bottom surface and a diameter larger than the shaft diameter of the rotating shaft. A cylindrical storage pot is joined to the outer peripheral side of the rotating shaft to store liquid. In addition, an intermediate cylinder fixed to the upper wall surface of the main body tank is disposed between the rotating shaft and the storage pot while having a clearance from the bottom surface of the storage pot. For this reason, due to the presence of the liquid stored in the storage pot, the rotating shaft can rotate while the gas is sealed between the inside of the main body tank and the outside.

  A liquid feed pipe whose base end side is connected to the replenishing tank side in which liquid is stored in a sealed state and whose distal end side is open into the intermediate cylinder feeds the liquid into the intermediate cylinder. Along with this, there is a gap between the bottom surface of the storage pot and the intermediate cylinder, and the mutual connection is established, so that the fed liquid is also replenished to the storage pot.

  Therefore, if the liquid stored in the intermediate cylinder decreases more than necessary due to atmospheric pressure fluctuation or evaporation in the main body tank, and the opening on the tip side of the liquid supply pipe is exposed outside the liquid level, this liquid supply pipe As the outside air outside the main body tank enters the liquid feeding pipe from the front end side, the outside air enters the replenishing tank through the liquid feeding pipe. As a result, an amount of liquid that matches the amount of outside air is fed into the storage pot from the sealed refill tank through the liquid feeding pipe, and the opening on the tip side of the liquid feeding pipe is hidden in the liquid. Until then, the liquid level in the intermediate cylinder rises and the liquid level in the storage pot rises accordingly.

  On the other hand, if the liquid level of the liquid stored in the intermediate cylinder rises more than necessary due to atmospheric pressure fluctuations in the main tank, the liquid overflows from the intermediate cylinder to the outside of the main tank, In addition, after the liquid in the storage pot has decreased and atmospheric pressure fluctuation has been suppressed, it is considered that the opening on the tip side of the liquid feeding pipe is exposed outside the liquid surface. Also in this case, the liquid is fed from the replenishing tank into the storage pot through the liquid feeding pipe until the opening on the tip side of the liquid feeding pipe is hidden in the liquid.

  As described above, according to the gas seal device according to the present invention, as the liquid is surely sent from the replenishing tank through the liquid feeding pipe to the height at which the opening on the tip side of the liquid feeding pipe is hidden in the liquid, As a result of keeping the liquid level of the liquid stored in the intermediate cylinder connected to the storage pot constant, the gas seal between the inside of the main body tank and the outside is always shut off, while the rotation shaft Rotation is possible.

The operation of the gas seal device according to claim 2 will be described below.
The gas seal device according to the present invention has the same effect as that of the first aspect. However, the present invention has a configuration in which the first valve for opening and closing the liquid supply pipe is disposed in the liquid supply pipe, and the second valve for opening and closing the replenishment tank is attached to the upper part of the replenishment tank. ing.

  That is, according to the present claim, when the liquid in the replenishing tank decreases and the replenishing tank needs to be supplied with liquid, the first valve is closed and the second valve is opened. The liquid can be replenished into the replenishing tank through the second valve. Then, after the replenishment is completed, the first valve is opened and the second valve is closed, so that the liquid can be fed into the intermediate cylinder through the liquid feeding pipe while keeping the replenishing tank in a sealed state. Along with this, the liquid level of the liquid stored in the intermediate cylinder can be more reliably kept constant.

The operation of the gas seal device according to claim 3 will be described below.
The gas seal device according to the present invention has the same effects as those of the first and second aspects. However, in this claim, the replenishing tank has a configuration in which the amount of the liquid inside is formed so as to be visible from the outside.
That is, according to this claim, since the amount of liquid in the replenishing tank can be visually checked from the outside, the timing of liquid supply to the replenishing tank can be easily determined, and accordingly, in the same manner as described above, The liquid level of the liquid stored in the cylinder can be more reliably maintained constant.

The operation of the gas seal device according to claim 4 will be described below.
The gas seal device according to the present invention has the same effects as those of the first to third aspects. However, the present invention has a configuration in which the distal end side of the liquid feeding pipe is disposed between the intermediate cylinder and the rotating shaft.
That is, according to the present claim, the tip end side of the liquid feeding pipe opened in the intermediate cylinder is specifically disposed between the intermediate cylinder and the rotating shaft, and the liquid is fed by the liquid feeding pipe to the intermediate cylinder. It is possible to send in more reliably.

The operation of the gas seal device according to claim 5 will be described below.
The gas seal device according to the present invention has the same effects as those of the first to third aspects. However, in this claim, it has the structure that the front end side of the liquid feeding pipe is joined to the intermediate cylinder.
In other words, according to this claim, the tip end side of the liquid feeding pipe opened in the intermediate cylinder is specifically joined to the intermediate cylinder, and the liquid can be reliably fed into the intermediate cylinder by the liquid feeding pipe. become.

  As described above, according to the above configuration of the present invention, there is an excellent effect that it is possible to provide a gas seal device that can always keep a gas seal while keeping the liquid level of the stored liquid constant.

1 to 4 show a first embodiment of a gas seal device according to the present invention, and this embodiment will be described based on these drawings.
As shown in FIGS. 1 and 2, a digestion tank 14 which is a main body part of a digestion tank 12 to which the gas seal device 10 according to the present embodiment is applied has a cylindrical shape and its upper and lower parts are chamfered, respectively. For example, it is formed in such a shape.

The inside of the digestion tank 14 shown in FIG. 2, which is the main body tank, is a cavity for stirring the sludge S, and the upper wall surface 14A forms the upper part of the digestion tank 14. A motor 16 is not only installed on the upper wall surface 14A, but also the through wall 18 shown in FIG. 1 is formed in the upper wall surface 14A, and a rotating shaft 20 extending vertically downward is provided on the upper wall surface 14A. It penetrates the through hole 18 at a coaxial position. The rotational power of the motor 16 is transmitted to the rotary shaft 20 by a gear (not shown) interposed between the motor 16 and the rotary shaft 20.

  A large impeller 22 is attached to the tip portion of the rotary shaft 20 in the digestion tank 14, and a smaller small impeller 24 is attached to the base portion of the rotary shaft 20 in the digestion tank 14. . As the rotary shaft 20 rotates, a large impeller 22 that is positioned closer to the lower side in the digestion tank 14 and a small impeller 24 that is positioned closer to the upper side in the digestion tank 14 are Each will rotate.

  As shown in FIG. 1, a cylindrical storage pot in which the rotary shaft 20 near the upper wall surface 14 </ b> A in the digestion tank 14 has a bottom surface 26 </ b> A and has a diameter larger than the shaft diameter of the rotary shaft 20. The bottom surface 26 </ b> A is joined to the outer peripheral side of the rotary shaft 20 by welding or the like, and is arranged coaxially with the rotary shaft 20. For this reason, the storage pot 26 also rotates with the rotation of the rotating shaft 20.

  An intermediate cylinder 28 formed in a cylindrical shape having a smaller diameter than the storage pot 26 is fixed to the inner surface side of the through hole 18 formed in the upper wall surface 14 </ b> A of the digestion tank 14. The lower end side of the intermediate cylinder 28 is disposed between the rotary shaft 20 and the storage pot 26 while having a gap with the bottom surface 26 </ b> A of the storage pot 26.

  That is, the intermediate cylinder 28 is fixed in a coaxial positional relationship with the rotary shaft 20, but the diameter of the intermediate cylinder 28 is larger than the diameter of the rotary shaft 20 and smaller than the diameter of the storage pot 26. Become. As the liquid L such as water is stored in the storage pot 26, a gap exists between the bottom surface 26A of the storage pot 26 and the lower end portion of the intermediate cylinder 28. The liquid L is stored.

  As a result, even if there is a gap between the intermediate cylinder 28 and the rotary shaft 20 as shown in FIG. 1, the inside and outside of the digestion tank 14 are sealed with the liquid L, and the airtightness in the digestion tank 14 is sealed. Sex will be maintained. The difference between the liquid level on the outer peripheral side of the intermediate cylinder 28 and the liquid level on the inner peripheral side of the intermediate cylinder 28 in the storage pot 26 is the digestion tank that the liquid level on the outer peripheral side of the intermediate cylinder 28 faces. 14 is determined by the difference between the atmospheric pressure inside 14 and the atmospheric pressure outside the digestion tank 14 facing the liquid surface on the inner peripheral side of the intermediate cylinder 28.

  However, in the present embodiment, as the gas is generated from the sludge S present in the digestion tank 14, the atmospheric pressure in the digestion tank 14 is increased, for example, by about 200 mmAq to 300 mmAq with respect to the outside air outside the digestion tank 14. ing. From the above, the gas seal device 10 according to the present embodiment is configured to agitate the sludge S in the digestion tank 12 that is anaerobic as shown by the arrow B in FIG. , Which is employed as a seal for a stirring device including the rotary shaft 20, the large impeller 22, the small impeller 24, and the like.

  On the other hand, as shown in FIG. 1, a replenishment tank 32 that is sealed and stores a liquid L such as water is provided in an upper portion outside the digestion tank 14. The replenishing tank 32 is made of, for example, a transparent synthetic resin material, and the amount of liquid L such as internal water can be visually observed from the outside.

  In addition, the lower end portion of the replenishing tank 32 is connected to the proximal end side of the liquid feeding pipe 34 for sending the liquid L from the replenishing tank 32. By disposing the distal end side of the liquid feeding pipe 34 between the intermediate cylinder 28 and the rotary shaft 20, the distal end side of the liquid feeding pipe 34 is opened in the intermediate cylinder 28. The liquid feeding pipe 34 can feed the liquid L from the replenishing tank 32 into the intermediate cylinder 28.

  Further, a first valve 36 for opening and closing the liquid supply pipe 34 is disposed at a position in the middle of the liquid supply pipe 34 on the liquid supply pipe 34. However, the first valve 36 is in an open state and in a normal state. Has been. On the other hand, a second valve 38 for opening and closing the upper portion of the replenishing tank 32 is attached to the upper portion of the replenishing tank 32. The second valve 38 is normally closed, and the refilling tank 32 is sealed. The state is secured.

Next, the operation of the gas seal device 10 according to the present embodiment will be described.
According to the gas seal device 10 of the present embodiment, as shown in FIG. 1, the rotating shaft 20 that can rotate passes through the upper wall surface 14A that forms the upper portion of the digestion tank 14, and has a bottom surface 26A. On the other hand, a cylindrical storage pot 26 having a diameter larger than the shaft diameter of the rotating shaft 20 is joined to the outer peripheral side of the rotating shaft 20 to store the liquid L. An intermediate cylinder 28 fixed to the upper wall surface 14 </ b> A of the digestion tank 14 is disposed between the rotating shaft 20 and the storage pot 26 while having a gap with the bottom surface 26 </ b> A of the storage pot 26.

  For this reason, the liquid L is stored not only in the storage pot 26 but also in the intermediate cylinder 28 due to the gap between the bottom surface 26 </ b> A of the storage pot 26 and the intermediate cylinder 28. Accordingly, due to the presence of the stored liquid L, the rotary shaft 20 can rotate while sealing the gas between the inside of the digestion tank 14 and the outside.

  The base end side is connected to the replenishing tank 32 side where the liquid L is stored in a sealed state, and the distal end side is disposed between the intermediate cylinder 28 and the rotary shaft 20 so as to be within the intermediate cylinder 28. An open liquid feed pipe 34 feeds the liquid L into the intermediate cylinder 28. That is, the liquid level in the replenishing tank 32 is maintained in accordance with the difference between the atmospheric pressure and the air pressure in the sealed replenishing tank 32, and the liquid L is supplied from the replenishing tank 32 when necessary. To be sent out. Accordingly, a gap exists between the bottom surface 26 </ b> A of the storage pot 26 and the intermediate cylinder 28, so that the liquid L fed in is also replenished to the storage pot 26.

  Therefore, as shown in FIG. 3, when the liquid L stored in the intermediate cylinder 28 is reduced more than necessary, and the opening on the tip side of the liquid supply pipe 34 is exposed outside the liquid surface, the liquid supply pipe 34 Outside air enters the liquid feeding pipe 34 from the front end side, and this outside air enters the replenishing tank 32 through the liquid feeding pipe 34. As a result, an amount of the liquid L that matches the amount of outside air is fed into the storage pot 26 along the arrow A from the sealed refill tank 32 through the liquid feed pipe 34, and the liquid feed pipe 34. The liquid level in the intermediate cylinder 28 rises until the opening on the leading end side is hidden in the liquid L, and the liquid level in the storage pot 26 rises accordingly.

  On the other hand, when the liquid level of the liquid L stored in the intermediate cylinder 28 temporarily rises more than necessary, the liquid L overflows from the intermediate cylinder 28 to the outside of the digestion tank 14, and the inside of the intermediate cylinder 28 In addition, it is conceivable that the liquid L in the storage pot 26 decreases and the opening on the tip end side of the liquid feeding pipe 34 is exposed outside the liquid surface. Also in this case, the liquid L is fed from the replenishing tank 32 into the storage pot 26 through the liquid feeding pipe 34 until the opening on the tip side of the liquid feeding pipe 34 is hidden in the liquid L.

  As described above, according to the gas seal device 10 according to the present embodiment, the liquid L is supplied from the replenishing tank 32 through the liquid supply pipe 34 to the height at which the opening on the distal end side of the liquid supply pipe 34 is hidden in the liquid L. As a result of being always sent, the liquid level of the liquid L stored in the intermediate cylinder 28 connected to the storage pot 26 can be kept constant. As a result, a gas seal between the inside of the digestion tank 14 and the outside can be obtained. The rotating shaft 20 can be rotated while always reliably blocking.

  On the other hand, in the present embodiment, the replenishment tank 32 is not only formed so that the amount of the liquid L inside can be seen from the outside, but also the first valve 36 that opens and closes the liquid supply pipe 34. And a second valve 38 that opens and closes the replenishing tank 32 is attached to the top of the replenishing tank 32.

  That is, according to the present embodiment, since the amount of the liquid L in the replenishing tank 32 can be visually confirmed from the outside, the timing of the liquid supply to the replenishing tank 32 can be easily determined, and the liquid in the replenishing tank 32 can be determined. When L decreases and liquid supply to the replenishing tank 32 becomes necessary, the first valve 36 is closed and the second valve 38 is opened. Accordingly, the spout 40A of the additional tank 40 containing the liquid L such as water is attached to the upper part of the second valve 38 as shown in FIG. Since the liquid L in the replenishing tank 32 can be constantly maintained by replenishing the liquid L so as to fill the liquid L, the liquid level of the liquid L stored in the intermediate cylinder 28 can be more reliably maintained constant. After the replenishment is completed, the first valve 36 is opened and the second valve 38 is closed, and the liquid L is fed into the intermediate cylinder 28 through the liquid feed pipe 34 while the replenishment tank 32 is in a sealed state. Make it possible.

Next, a second embodiment of the gas seal device according to the present invention is shown in FIG. 5, and this embodiment will be described based on this drawing.
In the first embodiment, the distal end side of the liquid feeding pipe 34 is disposed between the intermediate cylinder 28 and the rotary shaft 20. In the present embodiment, the liquid feeding pipe 34 is arranged as shown in FIG. The tip side is joined to the outer peripheral surface of the intermediate cylinder 28 by welding or the like, and the liquid L is fed into the intermediate cylinder 28. That is, according to the present embodiment, the leading end side of the liquid feeding pipe 34 is joined to the intermediate cylinder 28 and opens into the intermediate cylinder 28, and the intermediate cylinder is formed from the outer peripheral side by the opening of the liquid feeding pipe 34. The liquid L can be reliably fed into the liquid crystal 28.

  Therefore, also in the present embodiment, when the opening on the front end side of the liquid supply pipe 34 is exposed outside the liquid surface, the outside air enters the liquid supply pipe 34 from the front end side of the liquid supply pipe 34. Outside air enters the replenishing tank 32 through the liquid feeding pipe 34. As a result, as in the first embodiment, the liquid level in the intermediate cylinder 28 rises in accordance with this embodiment until the opening on the tip side of the liquid feeding pipe 34 is hidden in the liquid L in this embodiment. As a result, the liquid level in the storage pot 26 also increases.

  As described above, also in the gas seal device 10 according to the present embodiment, the liquid level of the liquid L stored in the intermediate cylinder 28 connected to the storage pot 26 can be kept constant. The rotating shaft 20 can be rotated while always reliably blocking the gas seal with the outside.

  The gas seal device according to the above embodiment is applied to an anaerobic digester tank agitator for agitating sludge to digest the sludge, but in other fields having a rotating shaft. You may make it apply this invention to the seal of a tank. In the above embodiment, the replenishment tank is made of a transparent synthetic resin material, but a level meter that can visually observe the liquid level may be installed outside the tank, for example. For example, it is conceivable to form the replenishment tank with a metal or an opaque synthetic resin material. Further, the liquid feeding pipe may be formed by a rubber hose or the like, or may be formed by a metal or synthetic resin pipe. The liquid may also be other liquid such as rust preventive oil other than water.

It is an expanded sectional view of the gas seal device concerning a 1st embodiment of the present invention. It is a schematic sectional drawing of the digestion tank to which the gas seal apparatus which concerns on the 1st Embodiment of this invention is applied. It is an expanded sectional view of the gas seal device concerning a 1st embodiment of the present invention, and is a figure showing the state where the liquid level fell. It is an expanded sectional view of the gas seal device concerning a 1st embodiment of the present invention, and is a figure showing the state where a liquid is replenished in a replenishment tank. It is an expanded sectional view of the gas seal device concerning a 2nd embodiment of the present invention.

10 Gas seal device 14 Digestion tank (main body tank)
14A Upper wall surface 20 Rotating shaft 26 Storage pot 28 Intermediate cylinder 32 Replenishment tank 34 Liquid feed pipe 36 First valve 38 Second valve L Liquid.

Claims (5)

A main body tank for storing a stirring target inside;
An agitation rotating shaft that penetrates the upper wall of the main body tank and rotates to agitate the object to be agitated;
A storage pot composed of a bottom surface and a cylindrical side wall, the center of the bottom surface being joined to the outer periphery of the rotating shaft ,
While being positioned above the reservoir pot is composed of a cylindrical side wall, a lower edge of the side walls of the bottom and clearance of the reservoir pot and the side wall of the storage pot side wall thereof with said rotary shaft An intermediate cylinder disposed between and having an upper portion of the side wall fixed to the upper wall of the main body tank;
A replenishment tank in which seal liquid is stored;
A proximal end side connected to the replenishing tank, a distal end side opened into the intermediate cylinder, and a liquid feed pipe capable of feeding the seal liquid into the intermediate cylinder,
Seal liquid is stored in the storage pot and the intermediate cylinder, a replenishment tank is disposed above the seal liquid surface in a sealed state with the inside isolated from the outside air, and the leading end side of the liquid supply pipe is in the intermediate cylinder Opened in the sealing liquid, the sealing liquid in the intermediate cylinder is stored to a height exceeding the opening position on the tip side of the liquid feeding pipe,
When the sealing liquid in the storage pot and the intermediate cylinder is reduced and the opening on the tip side of the liquid feeding pipe is exposed from the sealing liquid, the outside air enters the replenishing tank through the opening on the tip side of the liquid feeding pipe, A configuration in which an amount of sealing liquid that matches the amount of outside air that has entered inside is sent out from the replenishing tank , and the sealing liquid is replenished into the intermediate cylinder until the opening on the tip side of the liquid feeding pipe is hidden in the sealing liquid. A gas seal device characterized by that.   The gas seal device according to claim 1, wherein a first valve for opening and closing the liquid supply pipe is disposed in the liquid supply pipe, and a second valve for opening and closing the replenishment tank is attached to an upper portion of the replenishment tank.   The gas seal device according to claim 1 or 2, wherein the replenishing tank is formed so that the amount of the liquid inside can be seen from the outside.   The gas seal device according to any one of claims 1 to 3, wherein a distal end side of the liquid feeding pipe is disposed between the intermediate cylinder and the rotating shaft.   The gas seal device according to any one of claims 1 to 3, wherein a leading end side of the liquid feeding pipe is joined to the intermediate cylinder.

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