JP2007289824A - Decanter-type centrifugal separator and its cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decanter-type centrifugal separator which can be cleaned certainly and efficiently. <P>SOLUTION: An outside rotary cylinder 1 is arranged inside a casing 3, and a sealing member 4 is arranged on a shaft part of the casing 3 for the outside rotary cylinder 1. Thus the interior of the casing 3 can be kept in a liquid reserving state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a decanter-type centrifuge, and more particularly to a continuous decanter-type centrifuge that requires CIP cleaning (stationary cleaning) and SIP cleaning (stationary sterilization treatment) in a production line for pharmaceuticals, foods, and the like. is there.

The decanter-type centrifuge includes an outer rotating cylinder that is disposed in a casing and rotates at a high speed, and a screw conveyor that is disposed in the outer cylinder so as to be relatively rotatable.
This decanter-type centrifuge supplies solids that have been separated by sedimentation by centrifugal force in the outer rotating cylinder when the supply liquid such as slurry is supplied from the inside of the screw conveyor into the outer rotating cylinder and the outer rotating cylinder rotates at high speed. Is scraped by the blades of a screw conveyor that rotates with a slight rotational difference on the same axis as the outer rotating cylinder.
Then, the solid material sequentially proceeds in the direction of the cake discharge portion at the tip of the outer rotating cylinder, and is subjected to a liquid removal action by centrifugal force on the slope leading to the cake discharge portion.
In addition, the separation liquid returns in the reverse direction in the centrifuged state, and is recovered from the separation liquid outlet via the variable impeller.

By the way, many processes of batch reaction production are observed in pharmaceutical and food production processes.
If processing time is available during this batch reaction production process, measures for thorough cleaning and sterilization of the production line are taken for products that may be altered or spoiled.
Among the production lines, continuous decanter centrifuges are widely used because solid-liquid separation can be performed continuously and efficiently.

Cleaning after the centrifugal operation of this continuous decanter centrifuge is called CIP cleaning, and the casing inner surface and the outer surface of the outer rotating cylinder are relatively easy due to the effect of the cleaning nozzle and the outer rotating cylinder mounted in the casing. Can be cleaned.
However, in the in-machine cleaning, since disassembly / open cleaning is not easy, the actual condition is that the CIP cleaning is performed by forward and reverse inching cleaning while supplying the cleaning liquid. A blind spot occurs where the cleaning liquid does not reach the inside of the screw conveyor barrel or the liquid supply pipe.
The liquid supply pipe is a double pipe, and a cleaning nozzle is provided in the outer pipe to clean the inside of the screw cylinder. However, it is still difficult to completely reach the cleaning liquid.
In addition, when performing inching cleaning with forward / reverse rotation while supplying cleaning liquid during in-machine cleaning, the centrifugal force is working, so the cleaning effect of the cake remaining in the clearance between the outer rotating cylinder and screw blades In addition, there was a problem that the liquid and cake that entered the gap could not be washed because the gap in the clearance portion was small.

  An object of the present invention is to provide a decanter centrifuge capable of performing cleaning reliably and efficiently and a cleaning method thereof in view of the problems of the conventional decanter centrifuge.

  In order to achieve the above object, a decanter type centrifuge of the present invention includes a decanter type centrifuge having an outer rotating cylinder for centrifuging a charged stock solution and a screw conveyor provided in the outer rotating cylinder so as to be relatively rotatable. In the separator, the outer rotating cylinder is disposed in the casing, and a seal member is disposed on a shaft portion of the outer rotating cylinder with respect to the casing so that the inside of the casing can be maintained in a liquid storage state.

  In this case, it is possible to use a seal member that expands by supplying pressurized air to the hollow portion and in which the pressure of the supplied pressurized air acts as a seal surface pressure.

  The decanter-type centrifuge cleaning method of the present invention, when cleaning the decanter-type centrifuge, liquid-tightly seals the shaft portion of the outer rotating cylinder with respect to the casing with a seal member, It is filled with cleaning liquid, and the screw conveyor is rotated relative to the outer rotating cylinder.

  According to the decanter centrifuge and the cleaning method thereof of the present invention, the outer rotating cylinder is disposed in the casing, the seal member is disposed on the shaft portion of the outer rotating cylinder with respect to the casing, and the inside of the casing is in a liquid storage state. When the decanter centrifuge is cleaned, the shaft portion of the outer rotating cylinder with respect to the casing is liquid-tightly sealed by the sealing member, and the casing is filled with the cleaning liquid, and the outer rotating cylinder is screwed with respect to the outer rotating cylinder. By rotating the conveyor relative to each other, the cleaning liquid is spread all the way inside the barrel of the screw conveyor and the clearance between the outer rotating cylinder and the screw blades, eliminating the blind spots where the cleaning liquid does not reach and remaining in normal cleaning. Can completely dissolve and wash cakes, etc., so that washing can be performed reliably and efficiently. That.

  In addition, by using a seal member that expands by supplying pressurized air to the hollow portion, and the pressure of the supplied pressurized air acts as a seal surface pressure, the seal member has a large diameter and is outside during normal centrifugal operation. The shaft portion can be easily and inexpensively sealed with respect to the casing of the outer rotating cylinder, which is subjected to a load due to the high-speed rotation of the rotating cylinder.

  Embodiments of a decanter centrifuge and a cleaning method thereof according to the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of a decanter type centrifuge and a washing method thereof according to the present invention.
This decanter type centrifuge has an outer rotating cylinder 1 for centrifuging the charged stock solution and a screw conveyor 2 provided in the outer rotating cylinder 1 so as to be relatively rotatable.
And this decanter type centrifuge arrange | positions the outer side rotation cylinder 1 in the casing 3, and arrange | positions the sealing member 4 in the axial part with respect to the casing 3 of the outer side rotation cylinder 1, and the inside of the casing 3 is a liquid storage state So that it can be maintained.

The outer rotating cylinder 1 has a substantially truncated cone-shaped body, and can be rotated at a high speed by a drive source (not shown) such as an inverter motor via a large-diameter pulley 51 on the distal end side.
A shaft portion of the outer rotating cylinder 1 with respect to the casing 3 includes a labyrinth seal 6 that acts during a centrifugal separation operation, and a seal member 4 disposed outside the labyrinth seal 6.
The labyrinth seal 6 is mainly for sealing the gas in the outer rotating cylinder 1 and is not completely liquid-tight. Therefore, the shaft portion is sealed by the seal member 4 during the cleaning operation.
Two drain port plugs 7 for discharging the cleaning liquid W of the outer rotary cylinder 1 are provided in the diameter direction of the outer rotary cylinder 1 at the portion having the maximum diameter of the outer rotary cylinder 1 (one is shown in the figure). (Omitted).

A variable impeller 8 is provided at the base of the outer rotating cylinder 1 so that the ratio between the sedimentation separation part and the liquid drainage part can be adjusted by changing the sedimentation depth. The centrifugally separated separation liquid is supplied from the variable impeller 8. It is introduced and collected from the separation liquid outlet 11 through the separation liquid pipe 10 disposed concentrically outside the liquid supply pipe 9.
On the other hand, a cake discharge portion 12 having a discharge hole 12 a is formed at the tip of the outer rotating cylinder 1, and a discharge portion casing 32 having a chute 32 a is provided around the cake discharge portion 12. As a part, it is arranged in a state of being separated from the main body casing 31.
As shown in FIG. 5, the centrifugally separated solid matter is discharged from the cake discharge portion 12 after being subjected to a dehydrating action by centrifugal force on the slope leading to the cake discharge portion 12 while being sent by the screw conveyor 2. The screw blade 21 is scraped and collected from the chute 32a.

The screw conveyor 2 has a hollow body having a substantially truncated cone shape disposed coaxially inside the outer rotary cylinder 1, and a drive source (not shown) such as an inverter motor via a small-diameter pulley 52 on the tip side. (Omitted) so that it has a rotational difference from the outer rotating cylinder 1 and can be rotated at a high speed.
The screw conveyor 2 is provided with screw blades 21, and the screw blades 21 carry the centrifugally separated solid matter to the front end side due to the rotational difference from the outer rotating cylinder 1 and discharge it from the cake discharge unit 12.
A liquid supply pipe 9 is disposed at the axial center of the screw conveyor 2, and the stock solution supplied from the liquid supply pipe 9 passes through the discharge port 22 of the screw conveyor 2 to the inside of the outer rotary cylinder 1. To be supplied.
In the present embodiment, the clearance between the screw blade 21 and the outer rotating cylinder 1 has a large gap so that the liquid and solids can be sufficiently washed.

The casing 3 includes a main body casing 31 that covers the body portion of the outer rotary cylinder 1 and a discharge portion casing 32 that covers the cake discharge portion 12 of the outer rotary cylinder 1. An extraction pipe 14 is installed.
A cleaning liquid outlet 31a is formed in the main body casing 31, and a chute 32a is formed in the discharge casing 32. The cleaning liquid outlet 31a and the chute 32a can be closed in a liquid-tight manner.
The outer casing 1 is disposed in the main casing 31 and the discharge casing 32 so as to pass through both of them. The shaft section of the outer casing 1 is located at the rear of the main casing 31 and the front of the discharging casing 32. And are provided respectively.
And as above-mentioned, this axial part is equipped with the labyrinth seal 6 which acts at the time of centrifugation operation | movement, and the sealing member 4 arrange | positioned on the outer side of this labyrinth seal 6. As shown in FIG.

As shown in FIG. 4, the seal member 4 is an annular tube body made of a rubber-like elastic body, and is disposed in the bearing-side groove 41.
The seal member 4 expands when pressurized air is supplied to the hollow portion 42, and a part of the seal member 4 protrudes from the groove 41 so that the pressure of the supplied pressurized air can act as a seal surface pressure.
By operating this seal member 4, the outer rotary cylinder 1 is pressed from the periphery and fixed in a state where it cannot rotate, and the cleaning liquid W that has passed through the labyrinth seal 6 is stopped by this seal member 4, thereby Can store the cleaning liquid W up to the upper limit.
This makes it possible to easily and inexpensively seal the shaft portion with respect to the casing 3 of the outer rotating cylinder 1 which is large in diameter and is subjected to a load due to high-speed rotation of the outer rotating cylinder 1 during normal centrifugal separation operation.
Further, as shown in FIG. 3, in this embodiment, a seal member 4 is also disposed near the separation liquid outlet 11. The seal member 4 prevents leakage of the cleaning liquid W flowing from the outer rotating cylinder 1 along the separation liquid pipe 10.
In addition, the seal member 4 is a mechanical that can seal the shaft portion of the casing 3 of the outer rotating cylinder 1 that has a large diameter and is subjected to a load due to high-speed rotation of the outer rotating cylinder 1 during normal centrifugal operation. Any seal member such as a seal can be used.

  Next, a cleaning method for the decanter type centrifuge of this embodiment will be described.

In this decanter centrifuge cleaning method, when the decanter centrifuge is cleaned, the shaft portion of the outer rotating cylinder 1 with respect to the casing 3 is liquid-tightly sealed by the seal member 4, and the inside of the casing 3 is cleaned with the cleaning liquid W. And the screw conveyor 2 is rotated relative to the outer rotating cylinder 1 (in this embodiment, the screw conveyor 2 is rotated at a relatively low speed while the outer rotating cylinder 1 is stopped). .
That is, after completion of the centrifugal separation operation, the cake remains of course inside the outer rotating cylinder 1, but the cake also adheres to the inner surface of the casing 3, the cake discharger 12, the outer surface of the outer rotating cylinder 1, and the like. ing.
In order to completely clean these cakes that remain, in addition to a normal cleaning method, the shaft portion of the outer rotating cylinder 1 with respect to the casing 3 is sealed in a liquid-tight manner by the seal member 4, and the inside of the casing 3 is also sealed. The outer rotating cylinder 1 and the screw conveyor 2 are immersed in the cleaning liquid W, and the cake is cleaned in this immersed state.

Next, an example of the washing method of the decanter type centrifuge will be described in more detail.
After the end of the centrifugal separation operation, the outer rotary cylinder 1 and the screw conveyor 2 are set to about half the rotational speed during the centrifugal operation, and then the cleaning liquid W is supplied from the cleaning nozzle 13 and the liquid supply pipe 9. The inner surface of the casing 3 and the outer surface of the outer rotating cylinder 1 are cleaned (see FIGS. 1 and 6).
At this time, in the case of the variable impeller 8, the separation liquid outlet 11 is repeatedly opened and closed several times.
When the separation liquid outlet 11 is closed, the cleaning liquid W can be stored in the outer rotary cylinder 1, and this cleaning liquid W can be sent to the cake discharge section 12 by the screw conveyor 2, so that the discharge section casing 32 is filled with the cleaning liquid W and the cake The discharge part 12 can be effectively cleaned (see FIGS. 7 and 8).

  After the cleaning is completed, the machine is temporarily stopped, and the cleaning liquid W is supplied again into the outer rotating cylinder 1, the screw conveyor 2 and the casing 3, and the outer rotating cylinder 1 and the screw conveyor 2 are rotated forward and reverse to perform cleaning by inching. After repeating several times, the rotation of the outer rotating cylinder 1 and the screw conveyor 2 is stopped.

  After removing the two drain port plugs 7 of the outer rotating cylinder 1 and supplying the cleaning liquid W again and again, the outer rotating cylinder 1 and the screw conveyor 2 are rotated forward and reverse to repeat cleaning by inching several times, and then the outer rotating cylinder 1 1 and the rotation of the screw conveyor 2 are stopped.

In order to dip and wash the outer rotating cylinder 1 and the screw conveyor 2 in the casing 3, both ends of the outer rotating cylinder 1 and the seal members 4 of the separation liquid pipe portion are operated to perform liquid-tight sealing. Thereafter, the cleaning liquid W is supplied from each cleaning nozzle 13 and the liquid supply pipe 9, and the inside of the casing 3 is filled with the cleaning liquid W (see FIG. 9).
At this time, the outer rotating cylinder 1 is liquid-tightly sealed and fixed by the seal member 4, and the drain port of the outer rotating cylinder 1 is positioned in the vertical direction, and an air pool is formed inside the outer rotating cylinder 1. Not to be.

After filling the inside of the outer rotating cylinder 1, the screw conveyor 2 and the casing 3 with the cleaning liquid W, the forward / reverse operation of only the screw conveyor 2 is repeated several times.
By operating the screw conveyor 2 forward / reversely, a turbulent flow is generated inside the outer rotating cylinder 1, and adheres to the cake remaining in the clearance between the outer rotating cylinder 1 and the screw conveyor 2 and the inside of the outer rotating cylinder 1. Immerse the cake (dissolution cleaning).

After the immersion cleaning, the cleaning liquid W in the casing 3 is discharged.
After discharging the cleaning liquid W in the casing 3, the three seal members 4 are released.

In order to completely wash away the remaining liquid at the time of immersion cleaning inside the outer rotating cylinder 1, screw conveyor 2 and casing 3, the outer rotating cylinder 1 is supplied while supplying the cleaning liquid W again to the cleaning nozzle 13 and the liquid supply pipe 9 of the casing 3. Then, the screw conveyor 2 is rotated forward and backward, and cleaning by inching is performed once or twice.
Then, after the supply of the cleaning liquid W is stopped and the screw conveyor 2 and the outer rotary cylinder 1 are drained, the rotation of the outer rotary cylinder 1 and the screw conveyor 2 is stopped.

Further, when steam extinction is performed, the seal member 4 is operated again to make the inside of the casing 3 hermetically sealed, and then steam is supplied from each cleaning nozzle 13 and the liquid supply pipe 9 to the outer rotary cylinder 1 and the screw conveyor 2. And supplied into the casing 3.
The supply amount and supply time of steam shall comply with the regulations.

After completion of the steam sterilization, the outer rotating cylinder 1 is rotated at a low speed in order to release the seal member 4 and discharge the drain water in the outer rotating cylinder 1.
After drain water is discharged, two drain port plugs 7 of the outer rotary cylinder 1 end are attached.

  As described above, in the decanter centrifuge and the cleaning method thereof according to the present embodiment, the outer rotating cylinder 1 is disposed in the casing 3 and the seal member 4 is disposed on the shaft portion of the outer rotating cylinder 1 with respect to the casing 3. Then, the inside of the casing 3 can be maintained in a liquid storage state, and when the decanter centrifuge is washed, the shaft portion of the outer rotary cylinder 1 with respect to the casing 3 is sealed in a liquid-tight manner by the seal member 4, and the casing 3 By filling the inside with the cleaning liquid W and rotating the screw conveyor 2 relative to the outer rotating cylinder 1, the cleaning liquid W is filled in the barrel of the screw conveyor 2 and at the corners of the clearance between the outer rotating cylinder 1 and the screw blades 21. Can be removed, the blind spot that the cleaning liquid W does not reach, the cake that remains in the normal cleaning can be completely dissolved and cleaned, Les, the washing can be performed reliably and efficiently.

  As mentioned above, although the decanter type centrifuge of this invention and its washing | cleaning method were demonstrated based on the Example, this invention is not limited to the structure described in the said Example, The range which does not deviate from the meaning The configuration can be changed as appropriate.

  The decanter centrifuge of the present invention and the washing method thereof include, for example, a protein because the cake and the like that remain in normal washing can be completely dissolved and washed to perform washing reliably and efficiently. The decanter centrifuge can be suitably used for a pharmaceutical or food production line such as a decanter centrifuge for centrifuging a stock solution.

It is sectional drawing which shows one Example of the decanter type centrifuge of this invention. It is an expanded sectional view showing the casing front part of the decanter type centrifuge. It is an expanded sectional view which shows the casing rear part. The sealing member is shown, (a) is a sectional view before expansion, and (b) is a sectional view after expansion. It is sectional drawing which shows the centrifugation operation | movement of the decanter type centrifuge. It is sectional drawing of the 1st process which shows the washing | cleaning driving | operation of the decanter type centrifuge. It is sectional drawing of the 2nd process which shows the washing | cleaning driving | operation of the decanter type centrifuge. It is sectional drawing of the 3rd process which shows the washing | cleaning driving | operation of the decanter type centrifuge. It is sectional drawing of the 4th process which shows the washing | cleaning driving | operation of the decanter type centrifuge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer rotating cylinder 2 Screw conveyor 21 Screw blade 22 Release port 3 Casing 31 Main body casing 31a Washing liquid outlet 32 Discharge part casing 32a Chute 4 Seal member 41 Groove 42 Hollow part 51 Large diameter pulley 52 Small diameter pulley 6 Labyrinth seal 7 Drain port plug 8 Variable impeller 9 Supply pipe 10 Separation liquid pipe 11 Separation liquid outlet 12 Cake discharge part 12a Discharge hole 13 Cleaning nozzle 14 Air vent pipe W Cleaning liquid

Claims (3)

  In a decanter-type centrifuge having an outer rotating cylinder that centrifuges a charged stock solution and a screw conveyor provided in the outer rotating cylinder so as to be relatively rotatable, the outer rotating cylinder is disposed in a casing and A decanter centrifuge characterized in that a seal member is disposed on a shaft portion of a rotating cylinder with respect to a casing so that the inside of the casing can be maintained in a liquid storage state.   The decanter type centrifuge according to claim 1, wherein the seal member is a seal member that expands by supplying pressurized air to the hollow portion, and the pressure of the supplied pressurized air acts as a seal surface pressure. .   When cleaning the decanter centrifuge according to claim 1 or 2, the shaft portion of the outer rotating cylinder with respect to the casing is liquid-tightly sealed with a sealing member, and the inside of the casing is filled with the cleaning liquid, A cleaning method for a decanter-type centrifuge characterized by relatively rotating a screw conveyor.

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