JP2007038160A - Centrifugal separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a solid in a liquid to be treated from sizing and realize the reduction of a maintenance operation such as cleaning by using the air-tight structure in a casing and employing a gas sealant of a non-contact type sealing device to a shaft sealing part in a centrifugal separator generating a pressure difference between inner and outer sides of the casing. <P>SOLUTION: The centrifugal separator is provided with an outer barrel bowl 4 rotating at a high speed, an inner barrel screw 7 installed so as to rotate at a desired rotation difference in the outer barrel bowl, and a feed pipe 13 inserted into the inner barrel screw and feeding a raw liquid, and which houses the outer barrel bowl in the casing 12 of the air-tight structure. The non-contact type sealing device is installed between a rotating part including the outer barrel bowl and the casing, and a flinger larger than the sealing surface of the sealing device is installed in the rotating part in the inner machine side of the sealing device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a centrifuge that separates a stock solution into a solid component and a liquid component using centrifugal force, and more particularly to a screw decanter type centrifuge that can continuously discharge a solid component separated by a screw.

  Centrifugal separators are used to separate solids and liquids in sewage treatment and various industrial wastewater treatments. The centrifuge contains the separated solids. There is a screw decanter type centrifuge that continuously discharges by a screw conveyor.

  As shown in Patent Document 1, the screw decanter type centrifuge has an outer cylinder bowl that rotates at a high speed, and a screw conveyor that rotates at a high rotational speed with a required rotational difference inside the outer cylinder, The outer body bowl is housed in a casing.

  The stock solution containing solids supplied to the outer shell bowl is separated into a liquid and a solid by centrifugal force, and the separated liquid flows out from one end of the outer shell bowl to the casing, and is applied to the wall surface of the outer shell bowl. The accumulated solid is scraped off by the screw conveyor, sent toward the other end surface of the outer shell bowl, and discharged to the casing through a discharge hole formed in the outer shell bowl.

  In a screw decanter centrifuge, if the stock solution to be treated contains harmful substances, or if the stock solution is an organic solvent, the casing must be sealed, and the inside of the casing must be exposed to the outside air. On the other hand, when a positive pressure is applied, the rotating shaft penetrating portion of the casing must be sealed so that liquid (mist containing solids) inside the casing does not leak to the outside.

  Conventionally, as seen in Patent Document 2, a labyrinth seal is known as a sealing device that seals a rotating shaft penetrating portion (see FIG. 2).

  Furthermore, a sealing device using both a labyrinth seal and a gas seal is also known.

  With reference to FIG. 6, a seal device 18 using both a labyrinth seal and a gas seal will be described.

  In FIG. 6, reference numeral 19 denotes a structural member of the apparatus. A hole 22 is formed in the structural member 19, a rotating shaft 21 is inserted into the hole 22, and the rotating shaft 21 has a narrow neck portion. 24. The right side of the structural member 19 indicates the inner side of the apparatus.

  A seal seat 23 is fixed to the structural member 19, and the seal seat 23 has a ring portion 23 a, and the ring portion 23 a is fitted in the hole 22 in an airtight manner.

  A sleeve 25 is fitted into the rotary shaft 21 in an airtight manner, and the rotary shaft 21 has the neck portion 24 having a small diameter. An inner edge portion 26 that is loosely fitted to the neck portion 24 is formed at one end of the sleeve 25, and a flange portion 27 that extends in the outer diameter direction is formed at the other end. A rotating ring 28 is stopped and provided on the sleeve 25 so as to overlap with the flange portion 27, and the outer peripheral surface of the rotating ring 28 and the outer peripheral surface of the flange portion 27 are flush with each other. A rotary ring presser 29 is fitted on the sleeve 25, and the rotary ring 28 is pressed against the flange portion 27 by the rotary ring presser 29. The rotating shaft 21, the sleeve 25, the rotating ring 28, and the rotating ring retainer 29 rotate together to form a rotating portion.

  A seal case 31 is fixed to the seal seat 23, and a labyrinth seal portion 32 is formed at an end of the seal case 31 on the seal seat 23 side so as to straddle a boundary portion with the seal seat 23. Reference numeral 32 faces the outer peripheral surface of the flange portion 27 and the rotary ring retainer 29 via a required gap. The seal case 31 forms a donut-shaped space around the sleeve 25, and a seal flange 33 is fixed to the seal case 31 so as to close the space.

  A space surrounded by the rotary ring retainer 29, the seal case 31, and the seal flange 33 is left around the sleeve 25, and a ring-shaped seal ring 34 is accommodated in the space, and the seal ring 34 is It is slidable in the axial direction with respect to the seal flange 33, is urged toward the rotary ring retainer 29 by a spring 35, and is stopped by a pin 40. A seal seat 36 is embedded in a surface of the rotating ring 28 facing the seal ring 34, and an air pocket groove 37 is formed in a circular shape on the surface of the seal ring 34 facing the seal seat 36.

  A gap is formed between the seal ring 34 and the seal case 31, and two seal members 38, 38 such as two O-rings are provided between the seal ring 34 and the seal case 31, An airtight ring-shaped gap 39 sealed by the seal member 38 is formed between the seal ring 34 and the seal case 31.

  A seal gas supply path 41 connected to a seal gas supply source of an inert gas such as nitrogen gas is communicated with the gap 39, and an L-shaped communication path 42 is formed at a required portion of the seal ring 34. One end of the communication path 42 opens into the gap 39 and the other end opens into the air pocket 37.

  When the seal gas is supplied to the seal gas supply path 41 and the gap 39, the seal gas flows out from the entire circumference through the communication path 42 and the air pocket 37 through the gap between the seal seat 36 and the seal ring 34. A gas seal layer is formed between the seal seat 36 and the seal ring 34, and a gas seal portion 30 is formed between the seal ring 34 and the rotary ring 28.

  When the inside of the apparatus has a positive pressure with respect to the outside, the labyrinth seal portion 32 and the gas seal portion 30 are provided between the rotating portion including the rotating shaft 21 and the fixed portion such as the structural member 19. Sealed by.

  When the sealing device 18 using a labyrinth seal or a labyrinth seal and a gas seal is applied to a screw decanter centrifuge, the target of sealing is a liquid or solid mist, and these are the labyrinth seal portion. When entering 32, the groove of the labyrinth seal is filled with a solid material, and adheres to the seal surface of the gas seal portion 30 to cause seizure, which may cause a seal failure.

  Conventionally, periodic cleaning has been required to prevent a sealing failure.

Japanese Utility Model Publication No. 3-56652

JP 2001-132640 A

  In view of such a situation, the present invention uses a gas seal which is a non-contact type sealing device for a shaft seal portion in a centrifuge having a sealed structure and generating a pressure difference between the inside and the outside of the casing. It is intended to prevent seizure due to the solid matter inside and reduce maintenance work such as cleaning.

  The present invention comprises an outer body bowl that rotates at a high speed, an inner body screw that is provided in the outer body bowl so as to rotate at a required rotational difference, and a feed pipe that is inserted into the inner body screw and supplies a stock solution. A centrifuge in which the outer shell bowl is housed in a sealed casing, and a non-contact type sealing device is provided between the casing and the rotating part including the outer shell bowl, and the seal The present invention relates to a centrifuge in which a flinger having a diameter larger than that of the sealing surface of the sealing device is provided in the rotating part inside the device.

  The present invention also relates to a centrifuge in which a liquid return protrudes from the periphery of the flinger toward the inside of the machine, and a cylindrical portion facing the outer peripheral surface of the flinger with a required gap is provided on the casing side. The present invention relates to a centrifuge provided in the above.

  Further, the present invention relates to a centrifuge in which the sealing device is configured by arranging a first labyrinth seal portion, a gas seal portion, and a second labyrinth seal portion from the inside of the apparatus.

  Further, the present invention provides a centrifugal separator in which a gas seal portion is provided between a support portion and a rotating portion of the feed pipe, and a cylindrical liquid receiver that shields the gas seal portion is provided at an end portion of the rotating portion. Related to the machine.

  Furthermore, the present invention relates to a centrifuge in which a liquid return protrudes from an inner edge of the tip of the liquid receiver, and is located inside a support portion of the feed pipe and faces a ring protrusion so as to face the liquid return. The present invention relates to a centrifuge provided with a strip.

  According to the present invention, an outer drum bowl that rotates at a high speed, an inner drum screw that is provided in the outer drum bowl so as to rotate at a required rotational difference, and a feed that is inserted into the inner drum screw and that supplies a stock solution. In a centrifuge having a pipe and the outer shell bowl housed in a sealed casing, a non-contact type sealing device is provided between the casing and the rotating part including the outer shell bowl, Since a flinger having a diameter larger than the sealing surface of the sealing device is provided in the rotating part on the inner side of the sealing device, liquid and mist are prevented from entering the sealing device by the flinger rotating at high speed, and firing is prevented. The possibility of sticking or the like is eliminated, and stable operation is possible for a long time.

  Further, according to the present invention, the liquid return protrudes from the peripheral portion of the flinger toward the inside of the machine, and the cylindrical portion facing the outer peripheral surface of the flinger with a required gap is provided on the casing side. Therefore, the rotation of the flinger causes the liquid to fly away in the direction away from the sealing device, and further, the gap between the outer peripheral surface of the flinger and the cylindrical portion prevents the liquid and mist from entering the sealing device.

  Further, according to the present invention, the sealing device is configured by arranging the first labyrinth seal portion, the gas seal portion, and the second labyrinth seal portion from the inside of the machine, so that the sealing performance between the rotating portion and the fixed portion is improved. To do.

  According to the present invention, a gas seal portion is provided between the support portion and the rotating portion of the feed pipe, and a cylindrical liquid receiver for shielding the gas seal portion is provided at an end portion of the rotating portion. Therefore, the penetration of liquid and mist into the sealing device is prevented.

  Furthermore, according to the present invention, a liquid return protrudes from the inner edge of the tip of the liquid receiver, and a ring protrusion is provided inside the support portion of the feed pipe so as to face the liquid return. As a result, the liquid ejected from the liquid return is not scattered and exhibits excellent effects such as being effectively captured by the ring protrusion.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In FIG. 1, a screw decanter centrifuge is outlined.

  The outer body bowl 4 is rotatably supported on the frame 1 through bearing units 2 and 3, and a pulley 10 is attached to one end of the outer body bowl 4, and a main body driving motor 5 is attached to the pulley 10 with a belt 6. The outer body bowl 4 is rotated at a high speed by the main body driving motor 5 through the belt 6 and the pulley 10.

  An inner cylinder screw 7 is concentrically and rotatably incorporated in the outer body bowl 4, and the rotation shaft of the inner body screw 7 and the outer body bowl 4 is connected by a planetary gear type differential transmission 8, The differential speed rotation shaft 9 of the sun gear of the differential transmission 8 is rotated by a reduction gear braking motor 11, and the differential speed rotation shaft 9 is rotated by the reduction gear braking motor 11, thereby A relative rotation ratio between the bowl 4 and the inner cylinder screw 7 is set, and the inner cylinder screw 7 rotates at a high speed and also slowly rotates with respect to the outer cylinder bowl 4.

  The outer body bowl 4 is covered with a casing 12 attached to the frame 1, and a feed pipe 13 extending coaxially with the inner body screw 7 is communicated with the inner body screw 7. A slurry stock solution containing a solid content is supplied into the inner cylinder screw 7.

  The casing 12 has a liquid discharge port 14 and a solid discharge port 15 in the lower part, and the separated liquid and solid are discharged from the liquid discharge port 14 and the solid discharge port 15.

  The outline of the operation of the screw decanter centrifuge will be described with reference to FIG.

  The outer body bowl 4 is rotated at a high speed by the body driving motor 5, and the inner body screw 7 is rotated at a high speed by the brake motor 11 for reduction gear. The differential transmission 8 provides a rotational difference between the outer body bowl 4 and the inner body screw 7, and the inner body screw 7 rotates slowly relative to the outer body bowl 4 due to the rotational difference between the two. .

  The stock solution is fed from the feed pipe 13 into the inner drum screw 7, and the stock solution moves to the outer drum bowl 4 through the inner drum screw 7. The liquid is separated and the solid settles on the inner wall of the outer shell bowl 4.

  The separated liquid flows out into the casing 12 from a discharge hole 16 provided on one end face of the outer shell bowl 4, and the solid is put on the other end face of the outer shell bowl 4 by the inner shell screw 7. It is sent to the casing 12 through a discharge hole 17 formed in the outer body bowl 4. Further, the liquid is discharged from the casing 12, the separation liquid is discharged from the liquid discharge port 14, and the solid is discharged from the solid discharge port 15.

  In the screw decanter type centrifuge, the outer shell bowl 4 rotates at a high speed and the casing 12 is fixed. Therefore, the rotating shaft of the outer shell bowl 4 has a portion passing through the casing 12. A sealing device is provided.

  In particular, when the inside of the casing 12 has a positive pressure with respect to the outside air, when the stock solution contains harmful substances, or when the liquid of the stock solution is an organic solvent, the liquid (solid content) inside the casing 12 The rotating shaft penetrating part A (see FIG. 2) of the casing 12 must be sealed so that the mist including the mist does not leak to the outside.

  In the embodiment of the present invention, a non-contact type sealing device 45 described below is provided in the rotary shaft penetrating portion A, and a non-contact type sealing device 46 is provided on the support portion B at the shaft end of the feed pipe 13. Are provided.

  The sealing device 45 will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to what is shown in FIG. 6, and description is abbreviate | omitted about the detail.

  The sealing device 45 is airtightly provided in the rotary shaft penetrating portion A of the casing 12.

  The rotary shaft 21 has a stepped shape in which the diameter gradually decreases in a stepwise manner with the first small diameter portion 51, the second small diameter portion 54, and the third small diameter portion 55 toward the outside of the machine. A donut disk-shaped flinger 52 is fitted to the portion 51, and the flinger 52 has a larger diameter than a rotary ring 28 described later, and extends further outward than the outer peripheral surface of the rotary ring 28. A liquid return 53 is formed on the outer periphery of the flinger 52 so as to protrude toward the inside of the machine. The liquid return 53 is an inclined surface that is inclined inward from the center toward the outer periphery, or a curved surface that is curved.

  The rotary ring 28 is fitted on the second small diameter portion 54, and a rotary ring presser 29 is fitted on the second small diameter portion 54. The flinger 52 is pressed against the stepped surface of the shaft via the rotary ring 28, being pressed against the stepped surface of the shaft.

  The rotating shaft penetrating portion A (see FIG. 2) of the casing 12 is provided with a sealing device mounting hole 56, and a sealing case 57 is fitted into the sealing device mounting hole 56, and the fitting portion is a seal such as an O-ring. Sealed by member 58. A labyrinth ring 59 is fitted into an inner end portion (hereinafter referred to as an inner end portion) of the seal case 57, and the labyrinth ring 59 faces the outer peripheral surface of the rotating ring 28 to constitute a first labyrinth seal portion 61. .

  A labyrinth ring presser 62 is fixed to the inner end of the seal case 57 so as to fix the labyrinth ring 59, and a cylindrical part 63 is formed on the inner peripheral part of the labyrinth ring presser 62. It faces the outer peripheral surface of the flinger 52 with a slight gap. The inner end of the cylindrical portion 63 is in the same position as the apex of the liquid return 53 in the axial direction. A drain hole 60 is provided at the lowest position of the labyrinth ring presser 62 so as to penetrate the cylindrical portion 63 in the radial direction.

  A seal flange 64 is fixed to an outer end (hereinafter referred to as an outer end) of the seal case 57, and a ring-shaped seal ring storage space is formed by the seal flange 64, the seal case 57, and the rotary ring 28. A seal ring 34 is stored in the ring storage space.

  The storage structure of the seal ring 34 is the same as that described with reference to FIG. 6, and is biased toward the rotating ring 28 by the spring 35 and stopped by the pin 40. A gap 39 sealed by seal members 38, 38 is formed between the seal ring 34 and the seal case 57. The gap 39 communicates with the air pocket 37 by a communication path 42, and a seal gas supply path. 41 is connected to a seal gas supply source (not shown). A gas seal portion 30 is formed by the seal ring 34 and the rotary ring 28.

  A seal coupling 65 is fixed to the outer end of the seal flange 64, and a second labyrinth seal portion 66 is provided between the seal coupling 65 and the third small diameter portion 55.

  The operation of the sealing device 45 will be described.

  In the operating state of the screw decanter centrifuge, the inside of the casing 12 is at a positive pressure, and the rotating shaft 21 and the outer shell bowl 4 are rotating at high speed inside the casing 12.

  The liquid separated by centrifugation overflows from the discharge hole 16, is blown to the inner wall of the casing 12 by high speed rotation, flows down along the inner wall, and is discharged from the liquid discharge port 14. The mist-like liquid is rotated following the rotation of the outer shell bowl 4. The mist around the flinger 52 or the liquid adhering to the flinger 52 continues to the rotation of the flinger 52 and moves outward from the center. Since the liquid return 53 is formed on the periphery of the flinger 52, the continuous mist and liquid are blown to the surroundings and directed toward the inside of the machine.

  Therefore, mist and liquid are prevented from entering the labyrinth ring 59 side through the gap between the liquid return 53 and the cylindrical portion 63.

  Further, the inside and outside of the machine are sealed in three stages of the first labyrinth seal portion 61, the gas seal portion 30, and the second labyrinth seal portion 66, and high airtightness is obtained.

  Next, when the screw decanter type centrifuge is stopped, the rotational centrifugal force by the outer body bowl 4 is lost, so the liquid in the casing 12 falls at once.

  The outer peripheral surface of the flinger 52 is covered with the cylindrical portion 63, and the liquid falling direction and the direction of the gap between the flinger 52 and the cylindrical portion 63 are orthogonal to each other. Thus, liquid does not enter the first labyrinth seal portion 61 side from the gap.

  Further, when the rotation of the outer shell bowl 4 becomes low in the stop stroke, the stock solution (or water) held in the outer shell bowl 4 overcomes the centrifugal force and falls at a stretch. At this time, the stock solution is discharged in the axial direction from the discharge hole 16 and collides as a jet on the seal device 45 side, for example, the flinger 52. At this time, since the rotation of the flinger 52 is low, the effect of shaking off by the rotation cannot be expected. The collided stock solution changes the direction of the jet flow toward the outer body bowl 4 side by the action of the liquid return 53 at the side of the flinger 52 and the tip. This minimizes the penetration of the jet into the sealing device 45. The liquid that has entered slightly changes the direction of contact with the side surface of the labyrinth 59, flows down to the lower part of the labyrinth ring 62, and is further discharged from the drain hole 60 to the sealing device 45 side.

  Thus, it is possible to prevent the solid matter from filling the groove of the labyrinth seal or from adhering to the seal surface of the gas seal portion 30.

  Next, the sealing device 46 will be described with reference to FIG. In FIG. 5, the same components as those shown in FIGS. In FIG. 5, reference numeral 68 denotes a bracket provided on the frame 1 (see FIG. 2).

  A ring-shaped seal case 69 is fixed to the bracket 68, and a seal flange 71 is fixed to the side of the seal case 69 opposite to the pulley 10. The seal flange 71 has a ring-shaped convex portion 72 that protrudes toward the pulley 10, and the convex portion 72 is fitted in the seal case 69. A bank portion 73 is formed on the entire inner periphery of the front end of the convex portion 72, and a ring protrusion 74 is concentrically provided on the inner side of the convex portion 72. A drain passage 80 is formed in a lower portion of the seal flange 71, and one end of the drain passage 80 opens at the lowest position of the inner peripheral surface of the convex portion 72 and the other end is a lower surface of the seal flange 71. Is open.

  The feed pipe 13 penetrating the pulley 10 is supported by the seal flange 71, and a seal member 70 such as an O-ring is interposed between the seal flange 71 and the feed pipe 13.

  A ring-shaped ring seat 75 is fixed to an end surface of the pulley 10 facing the bracket 68. The ring seat 75 has a cylindrical portion 76, and the rotary ring 28 fitted to the cylindrical portion 76 is attached to the ring seat 75, and the rotary ring 28 is stopped by the ring seat 75. Seal members 81 and 82 are interposed between the pulley 10 and the ring seat 75, and between the ring seat 75 and the rotary ring 28, respectively, and the joint surfaces are sealed.

  A substantially cylindrical liquid receiver 77 is fixed to the end surface of the cylindrical portion 76, and the inner peripheral portion of the rotating ring 28 is held by the ring seat 75 and the liquid receiver 77. The liquid receiver 77 extends between the convex portion 72 and the ring ridge 74, the tip portion faces the ring ridge 74, and a liquid return 78 projects from the inner edge of the tip portion. . A seal ring 34 is accommodated in a space formed by the seal case 69, the convex portion 72, the rotary ring 28, and the liquid receiver 77. The storage structure of the seal ring 34 is the same as that described for the seal device 45. The liquid receiver 77 also functions as a cover that shields the space for housing the seal ring 34 and the periphery of the feed pipe 13.

  When the pulley 10 is rotated at a high speed by the main body driving motor 5, the ring seat 75, the rotary ring 28, and the liquid receiver 77 are integrally rotated at a high speed. A gas seal is formed by supplying a seal gas from the seal gas supply path 41 between the seal seat 36 and the seal ring 34.

  The liquid or mist that has entered the liquid receiver 77 from the periphery of the feed pipe 13 communicates with the liquid receiver 77 and is further blown to the center side by the liquid return 78. The liquid that has been blown flows down in contact with the ring protrusion 74, accumulates below the liquid receiver 77, passes through the liquid return 78, and is discharged from the drain flow path 80.

  Therefore, the liquid and mist leaked to the support portion of the feed pipe 13 do not enter the seal surfaces of the seal ring 34 and the rotary ring 28, and solid matter is prevented from adhering to the seal surface.

  Further, when the screw decanter type centrifuge is stopped, the liquid connected to the liquid receiver 77 falls at a time, but once accumulates in the lower part of the liquid receiver 77, and further, the inner peripheral surface of the convex portion 72. The bank portion 73 is prevented from moving to the inside of the machine and is discharged from the drain flow path 80.

  Therefore, even when the screw decanter centrifuge is stopped, the liquid is prevented from entering the gas seal portion.

  As described above, the rotating part and the fixed part are sealed with a gas seal or a labyrinth seal, the casing 12 is kept airtight, and the stock solution to be processed contains harmful substances, or the stock solution is organic. Even in the case of a solvent, leakage of harmful substances and organic solvent from the casing 12 is prevented. Further, since the rotating portion and the fixed portion are sealed in a non-contact manner, there is no wear and maintenance is easy.

It is the perspective view which fractured | ruptured a part which shows the screw decanter type | mold centrifuge with which this invention is implemented. It is a schematic sectional drawing of this screw decanter type centrifuge. It is sectional drawing which shows the principal part of embodiment of this invention. FIG. 4 is a partially enlarged view of FIG. 3. It is sectional drawing which shows the principal part of embodiment of this invention. It is sectional drawing which shows the conventional seal structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Frame 4 Outer cylinder bowl 5 Main body drive motor 7 Inner cylinder screw 8 Differential transmission 10 Pulley 11 Reduction gear brake motor 12 Casing 13 Feed pipe 14 Liquid discharge port 15 Solid discharge port 21 Rotating shaft 30 Gas seal part 34 Seal Ring 36 Seal seat 39 Gap 41 Seal gas supply path 42 Communication path 45 Seal device 52 Flinger 53 Liquid return 56 Seal device mounting hole 57 Seal case 59 Labyrinth ring 62 Labyrinth ring presser 63 Cylindrical portion 68 Bracket 71 Seal flange 72 Convex portion 73 Bank Portion 74 Ring protrusion 76 Cylindrical portion 77 Liquid receiver 78 Liquid return 80 Drain flow path

Claims (7)

  An outer cylinder bowl that rotates at a high speed, an inner cylinder screw that is provided in the outer cylinder bowl so as to rotate at a required rotational difference, and a feed pipe that is inserted into the inner cylinder screw and supplies a stock solution, In the centrifuge in which the outer shell bowl is housed in a sealed casing, a non-contact type sealing device is provided between the casing including the outer shell bowl and the casing, and the inner side of the sealing device. A centrifugal separator characterized in that a flinger having a diameter larger than the sealing surface of the sealing device is provided in the rotating part.   The centrifuge according to claim 1, wherein a liquid return protrudes from the periphery of the flinger toward the inside of the apparatus.   The centrifuge according to claim 1, wherein a cylindrical portion facing the outer peripheral surface of the flinger with a required gap is provided on the casing side.   The centrifuge according to claim 1, wherein the sealing device includes a first labyrinth seal portion, a gas seal portion, and a second labyrinth seal portion arranged from the inside of the machine.   The centrifuge according to claim 1, wherein a gas seal portion is provided between a support portion and a rotation portion of the feed pipe, and a cylindrical liquid receiver that shields the gas seal portion is provided at an end portion of the rotation portion. .   6. The centrifugal separator according to claim 5, wherein a liquid return protrudes from the inner edge of the tip of the liquid receiver.   The centrifuge according to claim 6, wherein a ring protrusion is provided inside the support portion of the feed pipe so as to face the liquid return.

Images