JP2005254190A - Decanter type centrifuge separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and economical technique for preventing liquid leakage from a solid matter discharge exit at the time of initial period of operation without requiring an operation apparatus or operation power exclusively for the purpose. <P>SOLUTION: The subject decanter type centrifuge separator has a supernatant solution discharge exit 4 at the same level as a solid matter discharge exit 3 or closer to the center axis x1 side of a rotation cylinder 1 than the solid matter discharge exit 3, and in this centrifuge separator, a level adjustment valve 10 having a flow channel 11 communicating the inside and the outside of the rotation cylinder 1 and a valve body 14 for opening or closing the flow channel 11 is installed at a position closer to a circumferential wall 1r side than to the solid matter discharge exit 3 in the rotation cylinder 1. The valve body 14 of the level adjustment valve 10 is so composed as to be energized toward the opening position by the centrifugal force owing to the rotation of the rotation cylinder 1 while toward the closing position by the discharge pressure of the solution passing the flow channel 11, and based on the balance of these energizing forces, the opening degree is adjusted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a decanter centrifuge.

  A decanter type centrifuge is a centrifuge used for clarification, dehydration, classification, etc. of a mixture (slurry) of a solid and a liquid. Generally, as shown in FIG. 6, a rotating cylinder (rotating bowl) is used. 1, a screw conveyor 2 arranged coaxially inside the rotating cylinder 1, a solid content outlet 3 provided at one end of the rotating cylinder 1, and a clarified liquid from the rotating cylinder 1 A clarified liquid discharge port 4 for discharging the liquid, and a raw liquid supply path 6 for supplying the raw liquid to the annular space 5 between the rotary cylinder 1 and the screw conveyor 2 from the outside through the shaft portion of the screw conveyor 2, The rotary cylinder 1 and the screw conveyor 2 are rotated in the same direction with a differential speed by the rotational drive sources 7 and 8, and the stock solution supplied to the annular space 5 through the stock solution supply path 6 is solid-liquid by centrifugal force. Separated and solid content rotating screw Discharged from propelled solids discharge port 3 by conveyer 2, clear liquid has a structure that is automatically discharged from the clarified liquid discharge port 4 by the liquid pressure generated by the centrifugal force.

  Further, the decanter type centrifuge is roughly classified into a shaft discharge type shown in FIG. 6 and a weir plate type shown in FIG. The shaft discharge type is a type in which a clarified liquid discharge port 4 is provided on the outer surface of the shaft part of the screw conveyor 2 and the clarified liquid is discharged to the outside of the rotating cylinder 1 through the shaft part. In addition, a clarified liquid discharge port 4 is provided on the side wall 1w opposite to the solid content discharge port 3 side in the rotary cylinder 1, and a weir plate 4d for fine adjustment of the liquid level is attached to the discharge port 4, The clarified liquid is discharged by overflow from the plate 4d.

  In these decanter centrifuges, when the clarified liquid discharge port 4 is disposed at the same level as the solid content discharge port 3 or closer to the central axis x1 side of the rotating cylinder 1 than the solid content discharge port 3, the stock solution When processing the undiluted solution (for example, sludge) that is difficult to transport the solid content in the rotating cylinder 1 to the solid content discharge port 3 side, the solid content discharge port 3 is blocked by the solid content S as shown in the figure during steady operation. Although the liquid component (mainly the clarified liquid) is not discharged from the solid content discharge port 3, the liquid level in the rotating cylinder 1 rises before this blocking action is exhibited in the initial stage of operation. There exists a problem that it will be discharged | emitted from the solid content discharge port 3 as it is or with a solid content.

  In order to solve this problem, conventionally, a technique has been proposed in which the height of the clarified liquid discharge port in the liquid level direction is moved by a fluid pressure cylinder (see Patent Document 1).

However, this prior art has a problem that a dedicated drive device and power are required, and equipment cost and running cost are increased. In addition, it is necessary to install equipment such as a cylinder and piping, which makes it difficult to apply to a shaft discharge type.
Japanese Patent Laid-Open No. 2001-314779

  Therefore, the main problem of the present invention is not only to solve the liquid leakage prevention from the solid content outlet at the initial stage of operation, but also requires a dedicated drive device and power, is simple and inexpensive, It is to provide a technology that can be easily applied.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A rotating cylinder, a screw conveyor arranged coaxially inside the rotating cylinder, a solid content outlet for discharging solid contents from the rotating cylinder, and a liquid for discharging a clarified liquid from the rotating cylinder With a clear liquid outlet,
The rotating cylinder and the screw conveyor are rotated in the same direction at a differential speed, the stock solution supplied to the annular space between the rotating cylinder and the screw conveyor is separated into solid and liquid by centrifugal force, and the solid content is the solid In a decanter centrifuge configured to be discharged from a minute outlet and the clarified liquid being discharged from the clarified liquid outlet;
The clarified liquid discharge port is disposed at the same level as the solid content discharge port or on the central axis side of the rotating cylinder from the solid content discharge port,
A level adjustment valve having a flow path communicating with the inside and the outside of the rotary cylinder and a valve element for opening and closing the flow path is provided at a position closer to the peripheral wall than the solid content outlet in the rotary cylinder,
In the level adjusting valve, the valve body is urged toward the open position by the centrifugal force generated by the rotation of the rotary cylinder, and is also urged toward the closed position by the discharge pressure of the liquid passing through the flow path. It is configured so that the opening degree is adjusted by the balance of these urging forces.
A decanter centrifuge characterized by the above.

(Function and effect)
The point of the present invention resides in a simple level adjusting valve that does not require a dedicated driving device and power. That is, in the level adjusting valve of the present invention, the opening of the valve body is adjusted using the centrifugal force associated with the rotation of the rotating cylinder and the discharge pressure of the liquid passing through the valve. Since it can be opened and closed by itself without any need and can be simply configured, it is inexpensive and can be easily applied to an axial center discharge type, and can be easily applied to existing facilities.

  Incidentally, there is a technique described in Japanese Patent Application Laid-Open No. 11-581 as having an on-off valve utilizing centrifugal force, but this prior art is for discharging liquid remaining in the rotating cylinder when operation is stopped. , Fundamentally different. In addition, even if this prior art is applied to liquid discharge from the solid content discharge port in the initial stage of operation, the open / close valve is fundamentally closed by a centrifugal force and closed by a spring spring. In addition, during steady operation, since the operation is continued in a state where the spring spring is extended by a force of several thousand G, there is a problem that the spring is easily extended and the durability is poor. This problem is not substantially present in the present invention.

<Invention of Claim 2>
The flow path of the level adjusting valve has an enlarged diameter portion at an intermediate portion thereof, a valve seat at a downstream end of the enlarged diameter portion, and the valve body is freely movable in the flow direction within the enlarged diameter portion. Thus, the enlarged diameter portion is arranged with a predetermined gap with respect to the inner peripheral surface of the enlarged diameter portion, and the enlarged diameter portion is formed so as to approach the central axis side of the rotating cylinder as it goes from the upstream side to the downstream side. And
The centrifugal force due to the rotation of the rotating cylinder moves the valve body to the upstream side of the flow path rather than the acting force that moves the valve body to the downstream side of the flow path because the discharge pressure of the liquid passing through the flow path. When the acting force is large, the valve body does not abut against the valve seat and moves to a position in the enlarged diameter portion where both acting forces are balanced. At this time, the valve body outer surface and the enlarged diameter portion inner circumferential surface The level adjustment valve is opened with an opening determined by the gap of
The discharge pressure of the liquid passing through the flow path moves the valve body to the downstream side of the flow path rather than the acting force that causes the centrifugal force due to the rotation of the rotating cylinder to move the valve body to the upstream side of the flow path. The decanter type centrifugal separator according to claim 1, wherein when the acting force is large, the valve body is brought into contact with the valve seat so that the level adjusting valve is closed.

(Function and effect)
The invention described in this section relates to a structure of a suitable level adjusting valve. In the invention described in this section, it is an extremely simple configuration in which a diameter-enlarged portion inclined in a predetermined direction with respect to the central axis of the rotating cylindrical body is provided, and a valve body is simply disposed inside the enlarged-diameter portion, Therefore, it is excellent in durability and maintainability.

<Invention of Claim 3>
The lid has a support shaft at the side of the upstream opening of the flow path of the level adjusting valve, and the valve body is configured to open and close the opening by rotating around the support shaft. Valve body,
The centrifugal force due to the rotation of the rotating cylinder is more in the direction of separating the valve body from the opening than the acting force that causes the discharge pressure of the liquid passing through the flow path to rotate the valve body toward the opening. When the acting force to rotate is large, the valve body does not close the opening, but rotates to a position where both acting forces are balanced, and the level adjusting valve is opened with an opening determined at this time. And
The centrifugal force generated by the rotation of the rotating cylinder rotates the valve body in a direction away from the opening, so that the discharge pressure of the liquid passing through the flow path moves the valve body toward the opening. The decanter type centrifuge according to claim 1, wherein when the acting force to rotate is large, the level adjustment valve is closed by the valve body closing the opening.

(Function and effect)
The invention described in this section also relates to a suitable level adjusting valve structure, and applies a so-called flap valve. The invention described in this section also has a very simple configuration, and therefore has excellent durability and maintainability.

<Invention of Claim 4>
When the discharge flow rate of the liquid discharged by the level adjustment valve reaches a predetermined flow rate set lower than the discharge flow rate of the clarified liquid discharged from the clarified liquid discharge port during normal operation, the level adjustment valve is closed. The decanter centrifuge according to any one of claims 1 to 3, wherein the decanter centrifuge is configured to be in a state.

(Function and effect)
The specific opening adjustment control of the level adjustment valve may be designed as appropriate. However, in order to prevent liquid leakage from the solid content outlet at the initial stage of operation, the configuration as described in this section can be used for steady operation. At the same time as the amount discharged during operation, the clarified liquid is automatically discharged at the original liquid level, which is preferable.

  As described above, according to the present invention, it is possible not only to solve the liquid leakage prevention from the solid content outlet at the initial stage of operation, but also to eliminate the need for a dedicated drive device and power, and to be simple and inexpensive. Advantages such as ease of application are provided.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)
1 and 2 show a level adjustment valve 10 according to the first embodiment. The level adjustment valve 10 includes a tubular portion 12P whose inner space forms the flow path 11, and a flange portion 12F provided at one end of the tubular portion 12P. When installing the level adjusting valve 10, as shown in FIG. 3, the wall portion 1w of the rotating cylinder 1 is provided with a level adjusting valve mounting hole to penetrate the tubular portion 12P, and the flange portion 12F is attached to the wall portion with bolts or the like. It is simply fixed by welding or the like, can be installed very easily, and can be applied to existing facilities. 3 is the same as the above-described conventional example except for the level adjusting valve 10, and the same reference numerals are used and description thereof is omitted.

  In the level adjusting valve 10 according to the first embodiment, the enlarged diameter portion 13 is provided in the middle portion of the flow path 11 of the tubular portion 12P, and the spherical valve body 14 is disposed in the enlarged diameter portion 13. Yes. The downstream end of the enlarged diameter portion 13 is a spherical valve seat 15 with which the spherical valve body 14 abuts.

  Further, a predetermined gap is provided between the outer peripheral surface of the spherical valve body 14 and the inner peripheral surface of the enlarged diameter portion 13 so that the spherical valve body 14 can freely move from one end to the other end in the flow path direction of the enlarged diameter portion 13. It is formed to have. In particular, in the illustrated embodiment, the enlarged diameter portion 13 has a shape whose diameter gradually increases from the valve seat 15 side (downstream side) toward the upstream side. As a result, the opening degree changes continuously according to the position of the spherical valve element 14 in the flow path direction in the enlarged diameter portion 13. The inner diameter of the expanded diameter portion 13 is made constant in the flow path direction and the opening degree is adjusted only by opening and closing, or the inner diameter of the expanded diameter section 13 is changed stepwise in the flow path direction to adjust the opening degree in stages. Can also be configured.

  In the present invention, the enlarged diameter portion 13 is formed so as to approach the central axis x1 side of the rotating cylinder 1 from the upstream side toward the downstream side. For this reason, in the level adjusting valve 10 of the present embodiment, the enlarged diameter portion 13 is slightly inclined with respect to the horizontal direction, and the level adjusting valve 10 is horizontally placed on the side wall 1w of the rotating cylinder 1 on the clarified liquid discharge port 4 side. It is configured to be attached so that the downstream side is closer to the central axis x1 side of the rotating cylinder 1 than the upstream side along the direction.

  As shown in FIG. 3, the level adjustment valve 10 configured in this way is positioned on the side wall 1 w on the side of the clarified liquid discharge port 4 of the rotating cylinder 1 (in other words, on the peripheral wall 1 r side relative to the solid content discharge port 3. It is provided at a position more distal to the central axis x1 of the cylinder 1. This mounting position can be set so that the liquid component is not discharged from the solid content discharge port 3 in consideration of the inner diameter of the rotating cylinder 1, the discharge flow / open / close switching flow rate of the level adjusting valve 10, the stock solution supply flow rate, and the like. . In a normal case, a level adjustment valve is provided in a radial direction range of 40 to 60% with respect to the inner diameter of the rotating cylinder 1, and the discharge flow rate / opening / closing of the level adjustment valve 10 is prevented so that liquid is not discharged from the solid content discharge port 3. It is preferable to design the switching flow rate, the stock solution supply flow rate, and the like.

  When the operation is started in the centrifuge thus configured, the rotating cylinder 1 and the screw conveyor 2 rotate in the same direction with a differential speed, and between the rotating cylinder 1 and the screw conveyor 2 via the stock solution supply path 6. The stock solution is supplied. The stock solution receives centrifugal force, stays on the peripheral wall 1r side of the rotating cylinder 1 and is separated into solid and liquid, while the liquid level rises toward the central axis x1 side of the rotating cylinder 1. The solid content is transferred to the solid content discharge port 3 by the rotating screw conveyor 2 and gradually accumulated. At the time of steady operation, as shown in FIG. 7, the outflow of liquid to the solid content outlet 3 is blocked by the accumulation of the solid content S. However, at the initial stage of operation, as shown in FIG. Since the accumulation of S is insufficient, the liquid level (mainly the clarified liquid) rises toward the solid content discharge port 3 before reaching the solid content discharge port 3 in a state where this blocking action is not exhibited. First, the position of the level adjusting valve 10 is reached. At this time, in the level adjusting valve 10, the centrifugal force due to the rotation of the rotating cylinder 1 causes the flow through the spherical valve body 14 rather than the action force that the discharge pressure of the liquid moves the spherical valve body 14 toward the valve seat 15 side. Therefore, the spherical valve element 14 does not abut against the valve seat 15 and moves to a position in the enlarged diameter portion 13 where both acting forces are balanced. When the valve body 14 is in the open state, the opening is determined by the gap between the outer surface of the valve body 14 and the inner peripheral surface of the enlarged diameter portion 13. Accordingly, the liquid component is discharged through the level adjustment valve 10 and is not discharged from the solid content outlet 3, and the rise in the liquid level is slowed down. In this state, the stock solution is sequentially supplied into the rotating cylinder 1, solid-liquid separation proceeds, and solid content S accumulates on the solid content outlet 3 side.

  As the solid content S accumulates, the liquid level in the rotary cylinder 1 gradually rises. Then, as shown in FIG. 6, when the accumulation of the solid content S is at the same level as in the steady operation and the liquid blocking action occurs, the discharge pressure of the liquid increases due to the increase in the liquid level, and the spherical shape The acting force that moves the valve body 14 to the valve seat 15 side exceeds the acting force that causes the centrifugal force to move the valve body 14 to the upstream side of the flow path, as shown by a two-dot chain line in FIG. The spherical valve body 14 comes into contact with the valve seat 15 and the level adjusting valve 10 is closed. Thereafter, the operation is steady, the liquid is not discharged from the solid part discharge port 3, and only the solid is discharged, and the clarified liquid is discharged from the clarified liquid discharge port 4.

  Switching between opening and closing of the level adjustment valve 10 corresponding to the occurrence of the liquid damming action is achieved by designing the discharge flow rate of the level adjustment valve 10 and the inclination of the enlarged diameter portion in consideration of the specifications of the centrifuge. can do. For example, in a normal case, the level adjusting valve 10 is configured to be closed when the discharge flow rate reaches a flow rate smaller than the discharge flow rate from the clarified liquid discharge port 4 during steady operation, for example, about 50%. Is desirable.

(Second Embodiment)
In the second embodiment, a so-called flap valve is applied as shown in FIGS. 4 and 5, and the inner space is provided at a tubular portion 22 </ b> P forming a flow path 21 and at one end portion of the tubular portion 22 </ b> P. The support shaft 24 is provided at a side portion of the upstream opening 23 of the flow path 21, and the upstream opening 23 of the flow path 21 is opened and closed by rotating around the support shaft. A lid-like valve body 25 (hereinafter referred to as a flap) is provided.

  However, it is not a simple flap valve, but according to the present invention, it is urged in the direction to be opened by centrifugal force and urged to be closed by exhaust pressure. That is, at the position where the flap 25 is stabilized by centrifugal force, the valve seat surface 26 determined by the peripheral edge of the upstream opening 23 of the flow path 21 does not contact the flap 25, and the upstream opening of the flap 25 and the flow path 21. The direction of the valve seat surface 26 of the upstream opening 23 is determined so that a circulation space is created between the upstream opening 23 and the flap 25 can receive the discharge pressure of the liquid flowing into the upstream opening 23.

  In the level adjustment valve 20 of the second embodiment, as shown in FIG. 3, a mounting hole is provided in the side wall 1w of the rotary cylinder 1 on the clarified liquid discharge port 4 side, and the tubular portion 21 is horizontally disposed in the mounting hole. (This point is the same as in the first embodiment), and the flow path in the tubular portion 21 extends linearly along the horizontal direction. For this reason, in the illustrated embodiment, a support shaft 24 is provided on the side that is on the central axis x1 side of the rotating cylinder 1 with respect to the upstream opening 23 of the flow path, and the upstream opening of the flow path 21 with respect to the support shaft 24 is provided. The flap 25 is extended to the side of the portion 23, and the valve seat surface 26 determined by the peripheral edge of the upstream opening 23 is inclined so as to be separated from the flap 25 as it moves away from the central axis x 1 of the rotating cylinder 1. In addition, in order to determine the orientation of the valve seat surface 26, an enlarged diameter portion 27 is provided at the upstream end portion of the tubular portion 22P, the valve seat surface 26 is formed by a stepped portion at the tip of the enlarged diameter portion 27, and a flap is formed. 25 rotates around the support shaft 24 in the enlarged diameter portion 27 so as to contact the valve seat surface 26.

  Furthermore, in the illustrated form, since the opening degree is determined by the gap between the periphery of the flap 25 and the inner surface of the enlarged diameter portion 27, the gap is increased (the enlarged diameter portion 27 is increased), or as in the illustrated example, It is preferable to form a flow groove 29 for securing the opening degree on the inner peripheral surface of the enlarged diameter portion 27.

  The level adjustment valve 20 thus configured can be attached in the same manner as in the first embodiment. When the liquid level reaches the level adjustment valve 20 at the initial stage of operation, the discharge pressure of the liquid passing through the flow path is the flap 25. The centrifugal force causes the flap 25 to rotate in a direction away from the valve seat 26, and the flap 25 is stable at a position substantially orthogonal to the horizontal direction. However, the upstream opening 23 of the flow path is not closed. Therefore, the level adjusting valve 20 is opened with the opening determined at this time, and the liquid component is discharged through the level adjusting valve 20, and is not discharged from the solid component discharge port 3, but the liquid level rises. Slows down. In this state, the stock solution is sequentially supplied into the rotating cylinder 1, the solid-liquid separation proceeds, the solid content is accumulated on the solid content outlet 3 side, and the solid content is at the same level as in the steady operation. , A liquid blocking action occurs. In such a state, this time, the centrifugal force causes the discharge pressure of the liquid passing through the flow path to turn the flap toward the valve seat 26 rather than the acting force that causes the flap 25 to rotate away from the valve seat 26. The acting force to be moved increases, and the valve element 25 closes the upstream opening 23 of the flow path 21 as indicated by a two-dot chain line in FIG. As a result, the level adjustment valve 20 is closed, and thereafter the steady operation is performed. The liquid content is not discharged from the solid content discharge port 3, but the solid content is discharged. The clarified liquid is discharged.

  In addition, since others are the same as that of 1st Embodiment, it abbreviate | omits description.

<Others>
In the above example, the level adjusting valve is attached as a unit to the hole provided in the wall 1w of the rotating cylinder 1, but the flow path of the level adjusting valve is directly formed in the rotating cylinder wall. A part of the piping can be used as a flow path of the level adjustment valve.

  In the present invention, the clarified liquid discharge port is at the same level as the solid content discharge port or disposed closer to the central axis side of the rotating cylinder than the solid content discharge port, regardless of whether it is a shaft discharge type or a barrier plate type. If so, it can be applied.

It is a longitudinal cross-sectional view which shows the level adjustment valve of 1st Embodiment. It is II-II sectional drawing of FIG. It is a longitudinal cross-sectional view which shows the outline | summary of the centrifuge which concerns on this invention. It is a longitudinal cross-sectional view which shows the level adjustment valve of 2nd Embodiment. It is a left view which shows the level adjustment valve of 2nd Embodiment. It is a longitudinal cross-sectional view which shows the outline | summary of the conventional decanter type centrifuge. It is a longitudinal cross-sectional view which shows the outline | summary of the conventional decanter type centrifuge.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotary cylinder, 2 ... Screw shaft, 3 ... Solid content discharge port, 4 ... Clarified liquid discharge port, 10,200 ... Level adjustment valve, 11, 21 ... Flow path, 14 ... Spherical valve body, 15, 26 ... Valve seat, 25 ... flaps.

Claims (4)

A rotating cylinder, a screw conveyor arranged coaxially inside the rotating cylinder, a solid content outlet for discharging solid contents from the rotating cylinder, and a liquid for discharging a clarified liquid from the rotating cylinder With a clear liquid outlet,
The rotating cylinder and the screw conveyor are rotated in the same direction at a differential speed, the stock solution supplied to the annular space between the rotating cylinder and the screw conveyor is separated into solid and liquid by centrifugal force, and the solid content is the solid In a decanter centrifuge configured to be discharged from a minute outlet and the clarified liquid being discharged from the clarified liquid outlet;
The clarified liquid discharge port is disposed at the same level as the solid content discharge port or on the central axis side of the rotating cylinder from the solid content discharge port,
A level adjustment valve having a flow path communicating with the inside and the outside of the rotary cylinder and a valve element for opening and closing the flow path is provided at a position closer to the peripheral wall than the solid content outlet in the rotary cylinder,
In the level adjusting valve, the valve body is urged toward the open position by the centrifugal force generated by the rotation of the rotary cylinder, and is also urged toward the closed position by the discharge pressure of the liquid passing through the flow path. It is configured so that the opening degree is adjusted by the balance of these urging forces.
A decanter centrifuge characterized by the above. The flow path of the level adjusting valve has an enlarged diameter portion at an intermediate portion thereof, a valve seat at a downstream end of the enlarged diameter portion, and the valve body is freely movable in the flow direction within the enlarged diameter portion. Thus, the enlarged diameter portion is arranged with a predetermined gap with respect to the inner peripheral surface of the enlarged diameter portion, and the enlarged diameter portion is formed so as to approach the central axis side of the rotating cylinder as it goes from the upstream side to the downstream side. And
The centrifugal force due to the rotation of the rotating cylinder moves the valve body to the upstream side of the flow path rather than the acting force that moves the valve body to the downstream side of the flow path because the discharge pressure of the liquid passing through the flow path. When the acting force is large, the valve body does not abut against the valve seat and moves to a position in the enlarged diameter portion where both acting forces are balanced. At this time, the valve body outer surface and the enlarged diameter portion inner circumferential surface The level adjustment valve is opened with an opening determined by the gap of
The discharge pressure of the liquid passing through the flow path moves the valve body to the downstream side of the flow path rather than the acting force that causes the centrifugal force due to the rotation of the rotating cylinder to move the valve body to the upstream side of the flow path. The decanter type centrifugal separator according to claim 1, wherein when the acting force is large, the valve body is brought into contact with the valve seat so that the level adjusting valve is closed. The lid has a support shaft at the side of the upstream opening of the flow path of the level adjusting valve, and the valve body is configured to open and close the opening by rotating around the support shaft. Valve body,
The centrifugal force due to the rotation of the rotating cylinder is more in the direction of separating the valve body from the opening than the acting force that causes the discharge pressure of the liquid passing through the flow path to rotate the valve body toward the opening. When the acting force to rotate is large, the valve body does not close the opening, but rotates to a position where both acting forces are balanced, and the level adjusting valve is opened with an opening determined at this time. And
The centrifugal force generated by the rotation of the rotating cylinder rotates the valve body in a direction away from the opening, so that the discharge pressure of the liquid passing through the flow path moves the valve body toward the opening. The decanter type centrifuge according to claim 1, wherein when the acting force to rotate is large, the level adjustment valve is closed by the valve body closing the opening.   When the discharge flow rate of the liquid discharged by the level adjustment valve reaches a predetermined flow rate set lower than the discharge flow rate of the clarified liquid discharged from the clarified liquid discharge port during normal operation, the level adjustment valve is closed. The decanter centrifuge according to any one of claims 1 to 3, wherein the decanter centrifuge is configured to be in a state.

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