JPH0933000A - Agitation system for liquid storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide soundness of an agitating system by preventing the occurrence of a vacuum part and a water hammer in an agitating line. SOLUTION: Outlet piping 7 is connected to the bottom of a liquid storage tank 1 and a pump 2 is connected to the outlet piping 7 through a pump inlet valve 3. Inflow piping 8 having a pump outlet valve 4 and a check valve 6 is connected to the pump 2, and one end part of the inflow piping 8 is connected to the liquid storage tank 1. The inflow piping 8 is branched from the other end and a transfer piping 9 is connected thereto through a check valve 5 to form an agitation line. The inflow piping 8 of the agitation line is connected in such a state to extend through the side or the bottom of the tank 1 or an air vent piping is connected to the inflow piping. This constitution prevents the occurrence of a vacuum part in the inflow piping 8 and prevents the occurrence of water hammer even when the vacuum part occurs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirring system in a liquid storage tank for uniformizing the liquid stored in the liquid storage tank.

[0002]

2. Description of the Related Art A liquid in a tank or a storage tank (hereinafter referred to as a tank) as a liquid storage tank for storing a liquid is transferred to another tank or equipment by a pump through a pipe connected to a hole formed in the bottom surface of the tank. Before being transferred, the process of stirring is performed for the purpose of homogenizing the liquid in the tank. A conventional stirring system for a liquid storage tank in this stirring process will be described with reference to FIG.

FIG. 4 is a piping system diagram showing a conventional stirring system, in which the liquid a stored in the tank 1 normally satisfies the L level which is the lowest level in the tank 1. Suppose there is. That is, at this time, the liquid level of the liquid a in the tank 1 is equal to or higher than the minimum level L level.

The liquid a in the tank 1 is moved by using an outlet pipe 7 connected to the bottom surface of the tank 1. Usually, stirring using a stirring line, transfer using a transfer line, stirring line and transfer line are used. Are transferred into the tank 1 or transferred into the tank 1 by the three methods of stirring transfer using
Each method will be described below.

In the tank 1, an outlet pipe 7 is connected to a hole formed in the bottom surface of the tank 1 and serves as a flow path for the liquid a.
Outlet pipe 7, pump inlet valve 3, outlet pipe 7, pump 2,
An agitation line is provided through which the liquid is returned from the upper part of the tank 1 to the tank 1 by the inflow piping 8, the check valve 6, the inflow piping 8, the pump outlet valve 4 and the inflow piping 8.

Further, an outlet pipe 7, a pump inlet valve 3, an outlet pipe 7, a pump 2, an inflow pipe 8, a check valve 5, a transfer pipe 9, an agitation and a transfer, which are connected to holes formed in the bottom of the tank 1. A transfer line is provided for transferring to a tank or equipment of another system through the switching valve 10 and the transfer pipe 11.

The agitation means that when the liquid a stored in the tank 1 is at the L level or higher, the pump inlet valve 3 is opened, the pump 2 is started, the pump outlet valve 4 is opened, and agitation and transfer are performed. The switching valve 10 is closed. As a result, the liquid a in the tank 1 is discharged from the hole formed in the bottom surface of the tank 1 to the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2, the inflow pipe 8, the check valve 6,
The inflow pipe 8, the pump outlet valve 4, and the inflow pipe 8 are circulated and discharged into the liquid in the tank 1. In this case, since the stirring and transfer switching valve 10 is closed, the check valve 5 and the transfer pipe 9 on the transfer line side are filled with liquid.

In this state, the tank 1 is used before and after using the stirring line.
It is water-sealed by the inflow pipe 8 into which the liquid a therein flows. By installing the above pipes and the like at a level lower than the L level in the tank 1, the inflow pipe 8, the outlet pipe 7, the pump inlet valve 3, the pump 2, the inflow pipe 8, the check valve 6, the pump outlet valve 4 The check valve 5 and the transfer pipe 9 are all filled with the liquid.

The distance from the top pipe level of the stirring line to the liquid level of the liquid a filled in the tank 1 is not limited, and the liquid a in the tank 1 is introduced from the upper part of the tank 1 into the inflow pipe. When returning to the inside of the tank 1 via 8 again, the height of the tank 1 may be 10 m or more. In that case, the vertical distance from the pipe at the top of the stirring line to the liquid surface of the liquid a filled in the tank 1 exceeds 10 m.

The transfer means that the liquid a stored in the tank 1 is L
When the level is higher than or equal to the level, the pump inlet valve 3 is opened, the pump 2 is started, the pump outlet valve 4 is closed, and the stirring and transfer switching valve 10 is opened. From the hole drilled on the bottom side, outlet pipe 7, pump inlet valve 3,
The pump 2, the inflow pipe 8, the check valve 5, the transfer pipe 9, the stirring and transfer switching valve 10, the transfer pipe 11, the tank of another system, and the device are transferred. The agitation transfer is to perform the agitation mode and the transfer mode at the same time.

As described above, in order to move the liquid in the tank 1 using the pipe connected to the bottom of the tank, stirring, transfer,
The method of agitation transfer is used, but the case taken up here is the case of agitation and agitation transfer.

[0012]

In the above configuration,
As is clear from FIG. 4, in the conventional stirring system for the liquid storage tank, the stirring line is reintroduced into the liquid in the tank 1 from the upper portion of the tank 1 through the inflow pipe 8.

At this time, before and after the stirring line is used, water is sealed by the inflow pipe 8 flowing into the liquid in the tank 1, and the liquid level in the tank 1 is kept below 10 m from the liquid level of the liquid a. When installed, the inlet pipe 8, outlet pipe 7, pump inlet valve 3, pump 2, inlet pipe 8, check valve 6, pump outlet valve 4, check valve 5, and transfer pipe 9 are all liquid a. Will be satisfied.

However, the lowest liquid level in the tank 1, that is, L
If the vertical distance from the level to the top of the stirring line exceeds 10 m, 10 m from the lowest liquid level in tank 1 when the stirring operation is stopped.
A vacuum portion is generated in the inflow pipe 8 from the top of the stirring line exceeding the above to the liquid surface of the liquid a filled in the tank 1.
As a result, at the same time when the pump outlet valve 4 is opened at the time of starting the stirring operation, the liquid hammer in the tank 1 suddenly flows into the vacuum section in the inflow pipe 8 to generate a water hammer, which deteriorates the soundness of the stirring system. is there.

The present invention has been made in order to solve the above problems, and has a system configuration in which a vacuum portion is not generated on the stirring line regardless of the height of the tank, or even if a vacuum portion is generated. An object of the present invention is to provide a stirring system for a liquid storage tank, which can improve the soundness of the stirring system by using a system that does not cause water hammer.

[0016]

According to the present invention, one end of an outlet pipe is connected to the bottom surface of a liquid storage tank, a pump is connected to the other end of the outlet pipe via a pump inlet valve 3, and the discharge side of this pump is connected. One end of an inflow pipe having a pump outlet valve and a check valve is connected to the other end, and the other end of the inflow pipe is immersed in the liquid in the liquid storage tank and branched from a side portion of the inflow pipe to form a check valve. A transfer line is connected via the above to form a stirring line, and the other end side of the inflow pipe of the stirring line penetrates a side surface of the liquid storage tank.

According to the present invention, regardless of the height of the tank, the system structure is such that no vacuum portion is formed on the stirring line.
Alternatively, the system should be able to prevent the occurrence of water hammer even if a vacuum is generated. Therefore, (1) The inflow pipe of the stirring line is penetrated from the side or bottom of the tank.

(2) In order to prevent the generation of a vacuum portion of the stirring line, an air vent pipe is connected to the inflow pipe to the tank.
(3) The operation of the pump will be a stirring system that gradually starts up at a low flow rate using a control system. In the above methods (1) and (2), the vertical distance from the top of the stirring line to the lowest liquid level, that is, the L level of the tank is 10 m.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a stirring system for a liquid storage tank according to the present invention will be described with reference to FIG. In the stirring system shown in FIG. 1, the liquid a stored in the tank (tank) 1 is in a state of normally satisfying the L level which is the lowest level in the tank 1. That is, it is assumed that the liquid level in the tank 1 is equal to or higher than the minimum level L level.

The liquid a in the tank 1 is sent into the tank 1 by three methods: stirring using a stirring line, transfer using a transfer line, and stirring transfer using a stirring line and a transfer line. Alternatively, it is transferred to the outside of the tank 1. Here, the stirring will be described below.

In the tank 1, an outlet pipe 7 is connected to a hole formed in the bottom surface of the tank 1 and serves as a flow path for the fluid a.
Outlet pipe 7, pump inlet valve 3, outlet pipe 7, pump 2,
A stirring line is provided which is returned to the tank 1 by the inflow piping 8, the check valve 6, the inflow piping 8, the pump outlet valve 4, and the inflow piping 8 penetrating the side surface of the tank 1.

Further, an outlet pipe 7, a pump inlet valve 3, an outlet pipe 7, a pump 2, an inflow pipe 8, a check valve 5, a transfer pipe 9, a stirring and a transfer which are connected to a hole formed in the bottom surface of the tank 1. A transfer line is provided for transferring to a tank or equipment of another system through the switching valve 10 and the transfer pipe 11.

The agitation means that when the liquid a stored in the tank 1 is at the L level or higher, the pump inlet valve 3 is opened, the pump 2 is started, the pump outlet valve 4 is opened, and the agitation and transfer are performed. By closing the switching valve 10, the liquid a in the tank 1 is discharged from the hole formed on the bottom surface of the tank 1 to the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2, the inflow pipe 8, the check valve. 6. The liquid is discharged into the liquid a in the tank 1 by the pump outlet valve 4 and the inflow pipe 8 penetrating the side surface of the tank 1. In this case, the stirring and transfer switching valve 10 is in a closed state, and therefore the check valve 5 and the transfer pipe 9 are also filled with liquid.

In this state, the tank 1 is used before and after the use of the stirring line.
It is water-sealed by the inflow pipe 8 flowing into the liquid inside, and is installed 10 m or less from the liquid level of the liquid a filled in the tank 1, so that the inflow pipe 8 and the outlet pipe 7 The pump inlet valve 3, the pump 2, the inflow pipe 8, the check valve 6, the pump outlet valve 4, the check valve 5, and the transfer pipe 9 are all filled with the liquid.

In this case, the liquid level of the liquid filled in the tank 1 from the top of the stirring line, that is, the minimum level L
If the vertical distance to the level is set to 10 m or less, no vacuum is generated in the inflow pipe 8 from the top of the stirring line to the liquid surface of the liquid a filled in the tank 1, which allows the pump to be started when the stirring motion is started. At the same time as opening the outlet valve 4,
There is no possibility that the liquid a in the tank 1 will flow into the vacuum section in the inflow pipe 8 at once, and the occurrence of water hammer can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIG. In this agitation system, the liquid a stored in the tank 1 is in a state of normally satisfying the L level which is the lowest level in the tank 1. That is, it is assumed that the liquid level in the tank 1 is equal to or higher than the minimum level L level.

The liquid a in the tank 1 is sent to the tank 1 by three methods, namely, stirring using a stirring line, transfer using a transfer line, and stirring transfer using a stirring line and a transfer line. It is transferred to the outside of the tank 1. Here, the stirring will be described below.

In the tank 1, an outlet pipe 7 is connected to a hole formed in the bottom surface of the tank 1, and the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2 and the inflow are used as fluid passages. A stirring line is provided which is returned to the tank 1 by the piping 8, the check valve 6, the inflow piping 8, the pump outlet valve 4, and the inflow piping 8 penetrating the bottom surface of the tank 1.

Further, an outlet pipe 7, a pump inlet valve 3, an outlet pipe 7, a pump 2, an inflow pipe 8, a check valve 5, a transfer pipe 9, a stirring and a transfer, which are connected to a hole formed in the bottom surface of the tank 1. A switching valve 10, a transfer pipe 9, a tank of another system, and a transfer line for transferring to equipment are provided.

In the stirring mode, when the liquid stored in the tank 1 is at the L level or higher, the pump inlet valve 3 is opened, the pump 2 is started, the pump outlet valve 4 is opened, and stirring and transfer are performed. The switching valve 10 is closed. As a result, the liquid a in the tank 1 is discharged from the hole formed on the bottom surface of the tank 1 through the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2, the inflow pipe 8, the check valve 6, the pump outlet valve 4, and The liquid is discharged into the liquid a in the tank 1 by an inflow pipe 8 penetrating the bottom surface of the tank 1.
In this case, the stirring and transfer switching valve 10 is in a closed state, and therefore the check valve 5 and the transfer pipe 9 are also filled with liquid.

In this state, the tank 1 is used before and after the stirring line is used.
It is water-sealed by the inflow pipe 8 flowing into the liquid a in the tank, and is 10 m from the liquid surface of the liquid a filled in the tank 1.
It is installed below. As a result, the inflow pipe 8, the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2, the inflow pipe 8, the check valve 6, the pump outlet valve 4, the check valve 5, and the transfer pipe 9 are all liquid. Will be satisfied.

If the vertical distance from the top of the stirring line to the liquid level of the liquid a filled in the tank 1, that is, the minimum level L is 10 m or less, the tank is filled from the top of the stirring line. No vacuum portion is generated in the inflow pipe 8 over the liquid surface of the flowing liquid.

As a result, at the same time as the pump outlet valve 4 is opened when the stirring operation is started, there is no risk that the liquid a in the tank 1 will flow into the vacuum section in the inflow pipe 8 at once, and water hammer can be prevented.

Next, a third embodiment of the present invention will be described.
In this agitation system, the liquid stored in the tank 1 is in a state of satisfying the L level which is the lowest level in the tank 1 normally. That is, it is assumed that the liquid level in the tank 1 is at the lowest L level.

The liquid a in the tank 1 is sent into the tank 1 by three methods, namely, stirring using a stirring line, transfer using a transfer line, and stirring transfer using a stirring line and a transfer line. Alternatively, it is transferred to the outside of the tank 1. Here, the stirring will be described below.

In the tank 1, an outlet pipe 7 is connected to a hole formed in the bottom surface of the tank 1, and the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2, are used as liquid flow paths. The inflow pipe 8, the check valve 6, the inflow pipe 8, the pump outlet valve 4, and the inflow pipe 8 having a length reaching from above the tank 1 into the liquid a are connected, and a stirring line for returning to the tank 1 is provided by these. Has been.

Further, an outlet pipe 7, a pump inlet valve 3, an outlet pipe 7, a pump 2, an inflow pipe 8, a check valve 5, a transfer pipe 9, a stirring and a transfer which are connected to a hole formed in the bottom surface of the tank 1. A transfer line for transferring from the switching valve 10 and the transfer pipe 11 to a tank or device of another system is provided.

A check valve 12 for vent and a vent pipe 13 are connected in series to the inflow pipe 8 having a length reaching from above the tank to the liquid a, and the lower end of the vent pipe 13 is directed to the inside of the tank 1. Has been.

In the stirring mode, when the liquid stored in the tank 1 is at the L level or higher, the pump inlet valve 3 is opened, the pump 2 is started, the pump outlet valve 4 is opened, and stirring and transfer are performed. The switching valve 10 is closed.

As a result, the liquid in the tank 1 is discharged from the hole formed in the bottom surface of the tank 1 to the outlet pipe 7, the pump inlet valve 3, the pump 2, the inflow pipe 8, the check valve 6, the pump outlet valve 4 and the inflow pipe. 8 is released into the liquid in the tank 1. In this case, the stirring and transfer switching valve 10 is in a closed state, and therefore the check valve 5 and the transfer pipe 9 are also filled with liquid.

In this state, the tank 1 is used before and after the use of the stirring line.
It is water-sealed by the inflow pipe 8 flowing into the liquid inside, and is installed at a position exceeding 10 m from the liquid level of the liquid filled in the tank 1, so that the outlet pipe 7 and the pump inlet The valve 3, pump 2, inflow pipe 8, check valve 6, pump outlet valve 4, check valve 5, and transfer pipe 9 are all filled with liquid.

In the inflow pipe 8, if the vertical distance from the liquid level of the liquid filled in the tank 1, that is, the L level is more than 10 m, the vacuum part is provided in the pipe exceeding 10 m. Occurs. In order to remove this vacuum portion, a through hole is opened in the inflow pipe 8, a vent pipe 13 is connected, and a check valve 12 for vent is installed.

As a result, even when a vacuum portion is generated in the inflow pipe 8, it is possible to break the vacuum portion in the inflow pipe 8 from the vent pipe 13 through the air vent into the vacuum portion in the inflow pipe 8. Become.

Since the vacuum portion generated in the inflow pipe 8 is broken, the pump outlet valve 4 is opened at the time of starting the stirring operation, and at the same time, the liquid a in the tank 1 flows into the vacuum portion of the inflow pipe 8 all at once. There is no fear and it is possible to prevent water hammer.

Next, a fourth embodiment of the present invention will be described with reference to FIG. Although FIG. 4 illustrates a conventional example, the present embodiment is an improvement of FIG. 4, and therefore the description will be made with reference to this.

The liquid a stored in the tank 1 is in a state of satisfying the L level which is usually the lowest level in the tank 1. That is, it is assumed that the liquid level in the tank 1 is equal to or higher than the minimum level L level.

Is the liquid a in the tank 1 fed into the tank 1 by three methods, namely, stirring using a stirring line, transfer using a transfer line, and stirring transfer using a stirring line and a transfer line. , Or transferred to the outside of the tank 1. Here, the stirring will be described below.

In the tank 1, an outlet pipe 7 is connected to a hole formed in the bottom surface of the tank 1, and the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2 and the inflow are used as liquid flow paths. A pipe 8, a check valve 6, an inflow pipe 8, a pump outlet valve 4 and an inflow pipe 8 are used to provide a stirring line for returning to the tank 1.

Further, an outlet pipe 7, a pump inlet valve 3, an outlet pipe 7, a pump 2, an inflow pipe 8, a check valve 5, a transfer pipe 9, a stirring and a transfer which are connected to a hole formed on the bottom surface of the tank 1. A transfer line for transferring to a tank or equipment of another system through the switching valve 10 and the transfer pipe 11 is provided.

In the stirring mode, when the liquid stored in the tank 1 is at the L level or higher, the pump inlet valve 3 is opened, the pump 2 is started, the pump outlet valve 4 is opened, and stirring and transfer are performed. The switching valve 10 is closed. As a result, the liquid in the tank 1 is discharged from the holes formed on the bottom surface of the tank 1 to the outlet pipe 7, the pump inlet valve 3, the outlet pipe 7, the pump 2, the inflow pipe 8, the check valve 6, the pump outlet valve 4, and It is discharged into the liquid in the tank 1 through the inflow pipe 8.

In this case, the agitation and transfer switching valve 10 is in the closed state, and therefore the check valve 5 and the transfer pipe 9 are also filled with the liquid. In this case, before and after using the stirring line, water is sealed by the inflow pipe 8 flowing into the liquid a in the tank 1.

From the liquid surface of the liquid filled in the tank 1 10
Since it is installed at a position exceeding m, outlet pipe 7, pump inlet valve 3, outlet pipe 7, pump 2, inflow pipe 8, check valve 6, pump outlet valve 4, check valve 5, transfer pipe 9
Will be all filled with liquid.

In the inflow pipe 8, when the vertical distance from the liquid level of the liquid a filled in the tank 1, that is, from the L level exceeds 10 m, the inside of the pipe exceeding 10 m is vacuumed. Part occurs.

When a vacuum is generated in the inflow pipe 8, the pump in the agitation system is gradually started at a low flow rate by inverter control, so that the liquid in the vacuum in the inflow pipe 8 gradually increases. It is possible to flow in and break the vacuum portion in the inflow pipe 8. Since the vacuum part generated in the inflow pipe 8 is broken, the pump outlet valve 4 is opened at the time of starting the stirring operation, and at the same time, the liquid in the tank 1 does not flow into the vacuum part in the inflow pipe 8 at once. It is possible to prevent water hammer.

[0055]

According to the present invention, a vacuum portion is not generated on the stirring line regardless of the height of the liquid storage tank. Further, by setting the distance from the top of the stirring line to the liquid surface of the liquid storage tank to 10 m or less, it is possible to prevent the generation of a vacuum portion in the stirring line. Thereby, water hammer can be prevented and the soundness of the stirring system can be improved.

Further, even when a vacuum portion is generated in the stirring line, by connecting a vent pipe to the inflow pipe that is immersed in the tank, or by starting the pump at a low flow rate,
Water hammer can be prevented.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing a first embodiment of a stirring system for a liquid storage tank according to the present invention.

FIG. 2 is a piping system diagram showing a second embodiment of the liquid storage tank stirring system according to the present invention.

FIG. 3 is a piping system diagram showing a third embodiment of the liquid storage tank stirring system according to the present invention.

FIG. 4 is a piping system diagram showing a conventional liquid storage tank stirring system.

[Explanation of symbols]

1 ... Tank (tank), 2 ... Pump, 3 ... Pump inlet valve, 4
... Pump outlet valve, 5 ... Check valve, 6 ... Check valve, 7 ... Outlet piping, 8 ... Inflow piping, 9 ... Transfer piping, 10 ... Stirring and transfer switching valve, 11 ... Transfer piping, 12 ... Reverse for vent Stop valve, 13… Vent piping.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazumichi Masuda 66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Engineering Co., Ltd.

Claims (5)

[Claims] 1. A bottom of a liquid storage tank is connected to one end of an outlet pipe, a pump is connected to the other end of the outlet pipe via a pump inlet valve 3, and a pump outlet valve and a check valve are provided on the discharge side of the pump. Is connected to one end of the inflow pipe, the other end of the inflow pipe is immersed in the liquid in the liquid storage tank, branched from the side of the inflow pipe and connected to the transfer pipe via a check valve. A stirring system for a liquid storage tank, wherein a stirring line is configured, and the other end side of the inflow pipe of the stirring line penetrates a side surface of the liquid storage tank. 2. The stirring system for a liquid storage tank according to claim 1, wherein the other end side of the inflow pipe of the stirring line penetrates the bottom surface of the liquid storage tank. 3. The agitation system for a liquid storage tank according to claim 1, wherein the other end side of the inflow pipe of the agitation line is branched from a side face and a vent pipe is provided through a check valve for a vent. 4. The stirring system for a liquid storage tank according to claim 1, wherein the pump is started up at a low flow rate. 5. The vertical distance from the top of the agitation line to the liquid level when the inflow pipe of the agitation line penetrates the side surface or the bottom surface of the liquid storage tank or is provided from above.
The stirring system for a liquid storage tank according to claim 1, wherein the stirring system is 10 m or less.