JP2009299839A - Gas seal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas seal device for reducing labor when replenishing liquid, by not only preventing leakage of the liquid but also labor for automatical supply of sealing liquid. <P>SOLUTION: A storage pot 26 is arranged in a part of a rotary shaft 20 near an upper wall surface 14A in a digestive tank 14. While having a clearance with a bottom surface 26A of the storage pot 26 on the inner surface side of a through-hole 18, an intermediate cylinder 28 formed in a smaller diameter than the storage pot 26 is fixed, and the liquid L is stored inside these. A buffer tank 30 storing the liquid L is arranged outside the digestive tank 14, and the other end side of an upper pipe 32 having one end connected to the intermediate cylinder 28 extends to the buffer tank 30, and the other end of the upper pipe 32 is arranged on a liquid level of the liquid L stored in the buffer tank 30. The other end of a lower pipe 34 having one end connected to a lower side part of the upper pipe 32 of the intermediate cylinder 28, is connected to a lower end part of the buffer tank 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas seal device that not only prevents overflow of liquid but also automatically supplies liquid for sealing to reduce labor when replenishing liquid, and relates to an anaerobic digestion tank It can apply to the stirring apparatus in.

  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 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, since it is necessary to prevent the gas in the digestion tank from flowing out to the outside, as the rotating shaft of the motor penetrates the upper side wall of the digestion tank, water or the like for sealing between the inside and outside air There is also a need for a gas seal device using a liquid. In the agitator, a storage pot 114 storing a sealing liquid as shown in FIG. 4 is provided on the rotating shaft 112 and sealed with this liquid. Thus, for example, a sealing device 110 having a structure for preventing gas outflow is employed.

And since the liquid such as water in the storage pot 114 for sealing gradually decreases due to evaporation or the like, an alarm is given to the outside when the liquid level decreases and the liquid level decreases. A level meter 116 is used in the gas seal device 110. Accordingly, when the liquid level of the liquid in the storage pot 114 reaches the level gauge 116, the level gauge 116 is activated to generate an alarm, and when this alarm is generated, the rotary shaft 112 and the intermediate cylinder 118 are generated. In general, the liquid is managed in such a manner that an operator replenishes the gap between them.
JP-A-8-10798 Japanese Patent Laid-Open No. 9-215916

  However, in the gas seal device 110 having the conventional structure, the liquid level D of the liquid filled in the gap between the intermediate cylinder 118 and the rotating shaft 112 changes when the pressure in the digestion tank greatly increases. As a result, the liquid overflows as indicated by an arrow E shown in FIG. 4, and as a result, the liquid may be applied to other parts, resulting in an obstacle to the digestion tank. Further, in the gas seal device 110 having the conventional structure, it is necessary to replenish the liquid frequently every time the gas seal device 110 is reduced, so that excessive labor is required for the operator.

Furthermore, when an alarm is not issued due to malfunction of the level meter 116 or the like, as a result of not being replenished without noticing that the liquid level has dropped, the water head pressure in the storage pot 114 is increased in the digestion tank. As a result, the gas could not withstand the pressure of the gas or the gas seal was incomplete, and the sealing function did not work, and there was a risk that methane gas or the like in the digestion tank would leak into the outside air.
In consideration of the above-described facts, the present invention provides a gas seal device that not only prevents the liquid from overflowing, but also automatically refills the liquid for sealing to reduce labor when replenishing the liquid. The purpose is to do.

A gas seal device according to claim 1, a rotating shaft that passes through an upper wall surface forming an upper portion of the main body tank and can rotate, and
A cylindrical storage pot that has a bottom surface and is formed with a diameter larger than the shaft diameter of the rotating shaft, and that is joined to the outer peripheral side of the rotating shaft and stores liquid;
An intermediate cylinder fixed to the upper wall surface of the main body tank so as to be disposed between the rotating shaft and the storage pot while having a gap with the bottom surface of the storage pot;
A buffer tank that is placed outside the body tank and stores liquid;
An upper pipe having one end connected to the intermediate cylinder and the other end extending to the buffer tank;
A lower pipe having one end connected to the lower part of the upper pipe in the intermediate cylinder and the other end connected to the buffer tank;
Equipped with.

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 buffer tank storing liquid is disposed outside the main body tank, and not only the other end of the upper pipe connected at one end to the intermediate cylinder extends to the buffer tank, but also the lower pipe below the upper pipe in the intermediate cylinder. The other end of the lower pipe whose one end is connected to the side portion is connected to the buffer tank. Along with this, when the pressure fluctuation in the main body tank is in a normal state where there is a liquid level between the upper pipe and the lower pipe, between the intermediate cylinder and the buffer tank via the lower pipe The liquid simply comes and goes.

  On the other hand, when the liquid level in the intermediate cylinder drops below the connection part of the lower pipe, the liquid in the buffer tank is not only sent into the intermediate cylinder by natural flow through the lower pipe but also the storage pot. Since there is a gap between the bottom surface of the tube and the intermediate cylinder and the two are connected to each other, this liquid is also fed into the storage pot. Therefore, since the liquid is sent out from the buffer tank, it becomes possible to prevent the water in the storage pot from being drained, so that it is ensured that the gas in the main body tank flows out to the outside as the liquid in the storage pot disappears. It is prevented.

  On the other hand, when the pressure in the main body tank rises more than necessary and the liquid level in the intermediate cylinder rises more than the connection part of the upper pipe, the liquid is sent from the intermediate cylinder through the upper pipe, Due to the natural flow of the liquid from the other end side of the upper pipe, the liquid returns from the intermediate cylinder to the buffer tank. As a result, even when the pressure in the main body tank increases more than necessary, the liquid stored in the storage pot and the intermediate cylinder does not overflow to the outside.

  Therefore, the liquid overflow does not affect the equipment installed outside the gas seal device, and at the same time, the liquid substantially circulates in the intermediate cylinder and the buffer tank, and the liquid gas seal device As a result, it is not necessary to replenish the liquid many times more than necessary, and it is possible to save time and effort for maintenance of the gas seal device.

  As described above, according to the gas seal device according to the present invention, since the intermediate pipe and the buffer tank are respectively connected by the upper pipe and the lower pipe, the overflow of the liquid from the inside of the intermediate pipe can be prevented. Instead, the liquid for sealing is automatically replenished to the intermediate cylinder to reduce the labor when replenishing the liquid.

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 other end of the upper pipe is disposed on the liquid surface of the liquid stored in the buffer tank, and the liquid is fed into the buffer tank from the intermediate cylinder.

  That is, according to the present claim, when the other end of the upper pipe is disposed on the liquid level of the liquid stored in the buffer tank, the liquid level in the intermediate cylinder rises more than the connection part of the upper pipe. In addition, as the liquid is sent from the intermediate cylinder to the buffer tank via the upper pipe, the liquid surely returns from the intermediate cylinder to the buffer tank.

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 other end of the lower pipe is connected to the lower end of the buffer tank, and the liquid is sent from the buffer tank to the intermediate cylinder.

  That is, according to this claim, when the other end of the lower pipe is connected to the lower end of the buffer tank, and the liquid level in the intermediate cylinder falls below the connection part of the lower pipe, the lower pipe is As the liquid is sent out from the buffer tank to the intermediate cylinder, the liquid is surely sent out in the intermediate cylinder and the storage pot.

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 one end of the upper pipe and one end of the lower pipe are respectively connected to portions outside the main body tank of the intermediate cylinder.

  That is, according to this claim, as the buffer tank is disposed outside the main body tank, one end of the upper pipe and one end of the lower pipe are respectively connected to a portion of the intermediate cylinder outside the main body tank. The upper pipe and the lower pipe can be installed without penetrating the upper wall surface of the main body tank. As a result, one end of the upper pipe and one end of the lower pipe can be connected to the intermediate cylinder easily and at low cost.

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 fourth aspects. However, in this claim, the level meter capable of detecting the liquid level of the liquid existing in the storage pot is configured to be installed in the storage pot.

  That is, according to the present claim, the level meter installed in the storage pot detects the liquid level of the liquid. Along with this, if the liquid in the buffer tank runs out during operation of the main tank and the liquid level in the storage pot drops more than necessary, this level meter detects the drop in the liquid level and An alarm comes out.

  As described above, according to the above-described configuration of the present invention, not only the overflow of the liquid can be prevented, but also the liquid for automatically sealing the liquid for sealing can be reduced in labor. It has an excellent effect that a gas seal device can be provided.

An embodiment of the gas seal device according to the present invention is shown in FIGS. 1 to 3, and the present 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 casing 52 shown in FIG. 1 formed in a disk shape is disposed on the upper wall surface 14 </ b> A, and the motor 16 is installed on the upper side of the casing 52.

  Further, a through hole 18 shown in FIG. 1 is formed in the upper wall surface 14A of the digestion tank 14, and a through hole 54 is formed in the casing 52, and a rotary shaft 20 extending vertically downward is provided. The thrust bearing 56 is attached to the rotary shaft 20 so as to not only pass through the through holes 18 and 54 at a coaxial position but also face the upper surface of the casing 52. 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. As described above, the gas seal device 10 according to the present embodiment rotates the motor 16 for agitating the sludge S in the digestion tank 12 that is anaerobic as shown by the arrow B in FIG. This is employed as a seal for a stirring device including a shaft 20, a large impeller 22, a small impeller 24, and the like.

  On the other hand, as shown in FIG. 1, for example, a synthetic resin buffer tank 30 in which the liquid L is stored is installed outside the digestion tank 14 and on the upper wall surface 14 </ b> A of the digestion tank 14. The upper side of the buffer tank 30 is open, and not only one end of the upper pipe 32 is connected to a portion of the intermediate cylinder 28 outside the digestion tank 14, but the other end side of the upper pipe 32 is connected to the upper side of the buffer tank 30. Is growing. Then, the other end of the upper pipe 32 is bent at a position on the liquid surface of the liquid L such as water stored in the buffer tank 30 so as to face downward.

  One end of the lower pipe 34 is connected to the lower part of the upper pipe 32 in the intermediate cylinder 28 outside the digestion tank 14, and the other end of the lower pipe 34 is connected to the buffer tank 30. Is connected to the lower end of the. In the storage pot 26, a capacitance type level meter 36 formed in a cylindrical shape for detecting the liquid level of the liquid L existing in the storage pot 26 is installed. The level meter 36 can detect the liquid level of the liquid L existing in the pot 26.

  On the other hand, a level detector 40 to which a level signal of the liquid L detected by the level meter 36 is sent is connected to the level meter 36 via a wire 38. In the level detector 40, It is determined whether or not the liquid level is equal to or higher than a predetermined height. Along with this, an on / off signal indicating whether the liquid level is higher than a predetermined level is sent to a level transmitter (not shown) installed outside the digestion tank 14, and for example, the operator supplies the liquid L when necessary. The gas seal device 10 can be added to the buffer tank 30.

  Further, a screwing portion 40A having a small diameter is provided on the lower end side of the level detector 40, and the screwing portion 40A is screwed into the screw hole 15 provided in the upper wall surface 14A. The level detector 40 is installed on the upper wall surface 14A. However, for example, a tape for sealing (not shown) is wound around the outer peripheral side of the screwing portion 40A, and the space between the screwing portion 40A and the screw hole 15 of the upper wall surface 14A is sealed with this tape.

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 in the direction of arrow C in FIG. 1 while sealing the gas between the inside of the digestion tank 14 and the outside.

  The buffer tank 30 storing the liquid L is disposed outside the digestion tank 14, and the other end of the upper pipe 32 having one end connected to a portion outside the digestion tank 14 of the intermediate cylinder 28 extends to the buffer tank 30. The other end of the upper pipe 32 is arranged on the liquid level of the liquid L stored in the buffer tank 30, so that the liquid L can be fed into the buffer tank 30 from the intermediate cylinder 28. Further, the other end of the lower pipe 34 whose one end is connected to the lower part of the upper pipe 32 in the portion outside the digestion tank 14 of the intermediate cylinder 28 is connected to the lower end of the buffer tank 30, and The liquid L can be sent out to the intermediate cylinder 28.

  Accordingly, in the gas seal device 10 of the present embodiment, the pressure fluctuation in the digestion tank 14 shown in FIG. 3 (A) such that there is a liquid level between the upper pipe 32 and the lower pipe 34 occurs. In the normal state, the liquid L goes back and forth between the intermediate cylinder 28 and the buffer tank 30 via the lower pipe 34 as indicated by the arrow F.

  On the other hand, as shown in FIG. 3B, when the liquid level in the intermediate cylinder 28 falls below the connecting portion of the lower pipe 34, the liquid L in the buffer tank 30 is moved through the lower pipe 34 to the arrow F. In addition to being sent out into the intermediate cylinder 28 by the natural flow shown by (2), since there is a gap between the bottom surface 26A of the storage pot 26 and the intermediate cylinder 28, the liquid L is stored. It is also fed into the pot 26. Accordingly, since the liquid L is sent out from the buffer tank 30, it becomes possible to prevent the water in the storage pot 26 from being drained, so that the gas in the digestion tank 14 is discharged to the outside as the liquid L in the storage pot 26 disappears. Outflow is reliably prevented.

  On the other hand, when the pressure in the digestion tank 14 increases more than necessary, and the liquid level in the intermediate cylinder 28 rises above the connection portion of the upper pipe 32 as shown in FIG. The liquid L is fed from the intermediate cylinder 28 through the line 32 as shown by an arrow F, and the liquid L is naturally flowed from the other end of the upper pipe 32 to the buffer tank 30 from the intermediate cylinder 28. Will come back. As a result, even when the pressure in the digestion tank 14 increases more than necessary, the liquid L stored in the storage pot 26 and the intermediate cylinder 28 does not overflow to the outside.

  Therefore, in the present embodiment, the overflow of the liquid L does not affect the equipment installed outside the gas seal device 10, and at the same time, the liquid L substantially passes through the intermediate cylinder 28 and the buffer tank 30. As a result of preventing the wasteful discharge of the liquid L from the gas seal device 10, it is not necessary to replenish the liquid L more times than necessary. It can be omitted.

  As described above, according to the gas seal device 10 according to the present embodiment, the liquid L from the intermediate cylinder 28 is obtained by connecting the intermediate cylinder 28 and the buffer tank 30 with the upper pipe 32 and the lower pipe 34, respectively. In addition to preventing the overflow of the liquid L, the liquid L for sealing is automatically replenished to the intermediate cylinder 28 to reduce the labor when replenishing the liquid L.

  Further, according to the present embodiment, as the buffer tank 30 is arranged outside the digestion tank 14, one end of the upper pipe 32 and one end of the lower pipe 34 are provided in a portion outside the digestion tank 14 in the intermediate cylinder 28. Are connected to each other, so that the upper pipe 32 and the lower pipe 34 can be installed without penetrating the upper wall surface 14A of the digestion tank 14. As a result, one end of the upper pipe 32 and one end of the lower pipe 34 can be connected to the intermediate cylinder 28 easily and at low cost.

  Furthermore, according to the present embodiment, the level meter 36 installed in the storage pot 26 detects the liquid level of the liquid L. Along with this, when the liquid L in the buffer tank 30 disappears during the operation of the digestion tank 14 and the liquid level in the storage pot 26 decreases more than necessary, the level meter 36 reduces the liquid level. Detects and issues an alarm to 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. Further, although the level meter is used in the above embodiment, the liquid can be automatically supplied from the buffer tank into the intermediate cylinder even when the level meter is not provided in the above embodiment. The liquid may also be other liquid such as rust preventive oil other than water.

It is an enlarged view of the gas seal device concerning one embodiment of the present invention, (A) is a sectional view and (B) is a 1B-1B arrow sectional view. It is a schematic sectional drawing of the digestion tank to which the gas seal apparatus which concerns on one embodiment of this invention is applied. It is explanatory drawing explaining the liquid level and the flow of a liquid of the gas seal apparatus which concerns on one embodiment of this invention, (A) is a figure which shows the case where a pressure fluctuation is a normal state, (B) It is a figure which shows the case where a liquid level falls below the connection part of lower piping, (C) is a figure which shows the case where a liquid level rises more than the connection part of upper piping. It is a figure of the conventional gas seal apparatus, Comprising: (A) is sectional drawing, (B) is 4B-4B arrow sectional drawing.

Explanation of symbols

10 Gas seal device 14 Digestion tank (main body tank)
14A Upper wall surface 20 Rotating shaft 26 Storage pot 28 Intermediate cylinder 30 Buffer tank 32 Upper pipe 34 Lower pipe 36 Level meter L Liquid

Claims (5)

A rotation shaft that can penetrate and rotate through the upper wall surface forming the upper part of the main body tank;
A cylindrical storage pot that has a bottom surface and is formed with a diameter larger than the shaft diameter of the rotating shaft, and that is joined to the outer peripheral side of the rotating shaft and stores liquid;
An intermediate cylinder fixed to the upper wall surface of the main body tank so as to be disposed between the rotating shaft and the storage pot while having a gap with the bottom surface of the storage pot;
A buffer tank that is placed outside the body tank and stores liquid;
An upper pipe having one end connected to the intermediate cylinder and the other end extending to the buffer tank;
A lower pipe having one end connected to the lower part of the upper pipe in the intermediate cylinder and the other end connected to the buffer tank;
A gas seal device comprising:   The gas seal device according to claim 1, wherein the other end of the upper pipe is disposed on the liquid level of the liquid stored in the buffer tank, and the liquid is fed into the buffer tank from the intermediate cylinder.   The gas seal device according to claim 1 or 2, wherein the other end of the lower pipe is connected to a lower end portion of the buffer tank, and liquid is sent from the buffer tank to the intermediate cylinder.   The gas seal device according to any one of claims 1 to 3, wherein one end of the upper pipe and one end of the lower pipe are respectively connected to a portion outside the main body tank of the intermediate cylinder.   The gas seal device according to any one of claims 1 to 4, wherein a level meter capable of detecting the liquid level of the liquid existing in the storage pot is installed in the storage pot.

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