Vertical centrifugal separator

A vertical centrifugal separator includes a casing, a bowl that is rotatably housed in the casing and provided to separate a solution to be processed which is supplied to an interior of the bowl into a liquid and a solid by an action of centrifugal force and discharge the liquid and the solid, and a discharge assembly that is rotatably housed in the bowl and provided to discharge the solid in the bowl. The bowl and the discharge assembly each have an engagement portion that is engaged or disengaged when the bowl and the discharge assembly are moved relative to each other in an axial direction and a position adjustment mechanism for adjusting a phase between the discharge assembly and the bowl relative to a rotation axis, for example, at a single relative position.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a centrifugal separator used for centrifugation of various solutions to be processed, and in particular, to a vertical centrifugal separator having a mechanism for automatically discharging solids produced during centrifugal operation.

2. Background Art

Generally, a vertical centrifugal separator includes a casing, a bowl housed rotatably in the casing, and a driving unit such as a motor for driving the bowl. In one known structure, the bowl is supported by, for example, bearings disposed on both the upper and lower sides of the casing (see, for example, Patent Literature 1). Such a vertical centrifugal separator further includes a heavy-liquid discharge portion disposed on the upper side of the casing to discharge a heavy liquid and a light-liquid discharge portion disposed above the heavy-liquid discharge portion to discharge a light liquid. This vertical centrifugal separator is configured such that the bowl is rotated at high speed (for example, 10,000 rpm or higher) during centrifugal operation with the solution to be processed being supplied to the bowl, so that a strong centrifugal force (for example, 20,000 G) is generated to discharge the heavy liquid and the light liquid separated from the solution being processed from the respective discharge portions.

CITATION LIST

Patent Literature

Patent Literature 1: International Publication WO2007/086114

SUMMARY OF INVENTION

Problems to be Solved by the Invention

The above conventional vertical centrifugal separator is not provided with a mechanism for automatically discharging the solids produced during centrifugal operation. Therefore, to remove the solids accumulated in the bowl, for example, the bowl must be detached from the casing after completion of the centrifugation of the solution being processed, and this requires much time and effort.

In particular, when a food or chemical is used as the solution to be processed, the inside of the bowl must be washed as clean as possible after the centrifugation of the solution is processed. In the above conventional vertical centrifugal separator, the bowl is detached from the main body and is then washed. Therefore, the bowl with the solids remaining present in the bowl must be washed, and the time and cost required to complete washing are high.

In view of the above circumstances, the present inventors have attempted to realize automatic discharge of the solids produced. In the course of the development, the inventors have proposed a structure in which a discharge assembly for discharging the solids to the outside of the bowl is disposed in the bowl and the bowl and the discharge assembly are allowed to rotate relative to each other. In the course of the development, the inventors have also proposed a so-called single-end supported structure in which a rotatable body including the bowl and the discharge assembly is rotatably supported at only one side (for example, the upper side) of the casing to increase the volume (diameter) of the bowl and to automatically discharge the solids, for example, rapidly and smoothly.

With such a structure in which the rotatable body supported at only its one side is driven, the dynamic balance between the bowl and the discharge assembly during high-speed rotation is an important factor, and an upset of the dynamic balance may cause vibrations, failure, and the like. Therefore, it is necessary to adjust the relative position (phase) between the bowl and the discharge assembly with respect to the rotation axis to a position that provides the best dynamic balance when the rotatable body rotates at high speed. In addition, it is necessary that the adjustment to the above position can be repeatedly reproduced even after various operations, maintenance, and the like.

Moreover, to perform maintenance, additional interior washing work, and the like, the bowl and other members must be detachable from the main body and in turn disassemblable. Therefore, there is a demand for a structure enabling simple and rapid disassembling work.

The present invention has been proposed to solve the above problems, and a first object of the invention is to provide a vertical centrifugal separator having a mechanism for automatically discharging solids produced during centrifugal processing after the processing.

A second object of the invention is to provide a vertical centrifugal separator having a mechanism in which the dynamic balance between a bowl and a wing portion during high-speed rotation is taken into consideration.

A third object of the invention is to provide a vertical centrifugal separator having a mechanism for automatically washing the bowl without detaching the bowl from the main body after a solution to be processed is centrifuged.

A fourth object of the invention is to provide a vertical centrifugal separator having a structure that enables simple and rapid disassembling work.

Means for Solving the Problems

To solve the foregoing problems, the main structure of a vertical centrifugal separator of the present invention includes: a casing; a bowl serving as a rotatable cylindrical body rotatably housed in the casing, the bowl separating a solution to be processed supplied to the inside of the bowl into a liquid and a solid by the action of centrifugal force, the separated liquid and solid being discharged from respective discharge portions; and a discharge assembly rotatably housed in the bowl, the discharge assembly discharging the separated solid from the bowl. In this configuration, the bowl and the discharge assembly each have an engagement portion being engaged or disengaged when the bowl and the discharge assembly are moved relative to each other in an axial direction and a position adjustment mechanism for adjusting the phase between the discharge assembly and the bowl relative to a rotation axis, and when the solution to be processed is centrifuged, the bowl and the discharge assembly integrally rotate in an engagement state in which the phase adjusted by the position adjustment mechanism is held, and the bowl and the discharge assembly are allowed to rotate relative to each other when the engagement state is released.

In the above configuration, when the solution to be processed is centrifuged, the bowl and the discharge assembly may rotate integrally at high speed while a centrifugal force of about 20,000 G is generated.

The bowl may include a bowl shell having a substantially cylindrical tank shape, to which the solution to be processed is supplied, and a hollow rotation shaft integrated with an upper portion of the bowl shell, and the discharge assembly may include a wing assembly having a plurality of wings formed integrally therewith and contained in the bowl shell and a rotation shaft protruding upward from the wing assembly and rotatably disposed in the hollow rotation shaft of the bowl. The engagement portion may be disposed on the lower side of the bowl and have a tapered portion that is tapered such that the inner diameter of the bowl increases in a downward direction, and the engagement portion of the discharge assembly may be disposed on the lower side of the discharge assembly and have a tapered portion that is tapered such that the width of the discharge assembly increases in the downward direction. When the discharge assembly moves upward relative to the bowl, the engagement state is established in which the bowl driven to rotate rotates integrally with the discharge assembly.

The position adjustment mechanism may include a first ring-shaped member disposed on the rotation shaft of the bowl and a second ring-shaped member disposed on the rotation shaft of the discharge assembly and faces the first ring-shaped member. A groove portion may be formed in one of the ring-shaped members, and a protruding portion fittable to the groove portion may be formed in the other one of the ring-shaped members.

Preferably, the groove portion includes a plurality of groove portions, and the protruding portion includes a plurality of protruding portions. The plurality of groove portions and the plurality of protruding portions are disposed at positions at which each of the protruding portions is fitted to a corresponding one of the groove portions when the rotation shafts are rotated relative to each other. To achieve this configuration, for example, the groove portions and the protruding portions are disposed at the positions arranged such that angles between the positions with respect to the center axis of the rotation shafts are different from each other.

Preferably, the vertical centrifugal separator further includes urging means for urging the discharge assembly in one direction, and the engagement portions are configured to bring the bowl and the discharge assembly into the engagement state by being urged by the urging means after completion of position adjustment by the position adjustment mechanism.

Preferably, in the vertical centrifugal separator, the bowl has a bearing mechanism that includes a plurality of ball bearings arranged in the axial direction, injection holes for lubricating grease that are formed in the ball bearings, and spacers that form spaces for reserving excess grease discharged from the ball bearings when the lubricating grease is fed thereinto, so that the bowl is allowed to rotate at high speed during centrifugation.

Preferably, the vertical centrifugal separator further includes a nozzle for supplying a washing solution to the casing and a sealing mechanism for hermetically sealing the casing so that the bowl, discharge assembly and the inside of the casing are washed in dipping washing. The sealing mechanism preferably has a structure including: a sealing member that is disposed at a connection portion of the casing and is expanded to improve sealing properties when a fluid for pressurization is urged and supplied to the inside of the sealing member; and means for supplying the fluid to the sealing member.

The discharge assembly of the vertical centrifugal separator may include a washing mechanism that includes: a hollow shaft disposed in a portion contained in the bowl; and a spray nozzle disposed so as to be in communication with the hollow shaft. The washing mechanism can wash the discharge assembly and the inside of the bowl by jetting a washing solution urged and supplied from one end of the hollow shaft outward from the spray nozzle. Preferably, the spray nozzle is disposed at a position that allows the washing solution urged and supplied to be jetted toward the discharge assembly and allows the washing solution reflected from the discharge assembly to impinge on an inner wall of the bowl. Washing water used for washing under water sealed conditions may be supplied from the spray nozzle.

The vertical centrifugal separator of the present invention may further include a disassembling mechanism that includes a fixed frame integrated with the casing, an upward-downward movable frame that is movable upward and downward relative to the fixed frame, and a rotationally movable frame to which the bowl is attached, to which the discharge assembly is detachably attached, and which is disposed so as to be rotationally movable relative to the upward-downward movable frame. The disassembling mechanism is configured to cause the upward-downward movable frame to be raised to pull the bowl and the discharge assembly out of the casing, and to cause the rotationally movable frame to rotationally move and then cause the upward-downward movable frame to be lowered, so that the discharge assembly is separated from the rotationally movable frame.

Advantageous Effects of Invention

In the vertical centrifugal separator of the present invention, the solids produced during centrifugation operation can be automatically discharged by releasing the engagement state between the bowl and the discharge assembly after completion of centrifugation of the solution to be processed and then rotating the discharge assembly relative to the bowl. Also, according to the present invention, the position adjustment mechanism for adjusting the phase between the discharge assembly and the bowl relative to the rotation axis to, for example, a single relative position is provided. When the solution to be processed is centrifuged, the discharge assembly and the bowl integrally rotate in an engagement state in which the phase adjusted by the position adjustment mechanism is held. When the engagement state is released, the discharge assembly and the bowl are allowed to rotate relative to each other. Therefore, during, for example, actuation or re-attachment after maintenance, the predetermined positions of the bowl and the discharge assembly that provide dynamic balance during high speed rotation can be reproduced. Accordingly, high speed rotation that provides, for example, a centrifugal force of 20,000 G can be achieved, and vibrations and the like are suppressed, so that the rotational movement is stabilized.

In the vertical centrifugal separator having the washing mechanism of the present invention, the inside of the bowl can be automatically washed after the centrifugation of the solution being processed. By setting the position of the spray nozzle to a position that allows the urged and supplied washing solution to be jetted toward the discharge assembly and allows the washing solution reflected from the discharge assembly to impinge on the inner wall of the bowl, the discharge assembly and the bowl can be washed simultaneously.

In the vertical centrifugal separator having the disassemblable structure of the present invention, the fixed frame and the casing are integrated, and the upward-downward movable frame that moves upward and downward relative to the fixed frame is provided. In addition, the rotatably movable frame is provided so as to be rotatably movable relative to the upward-downward movable frame, and the bowl is provided so as to be rotatably movable relative to the rotatably movable frame. Therefore, when the upward-downward movable frame is raised, the rotatably movable frame and the bowl are integrally raised, and the bowl can thereby be pulled upward out of the casing. In addition, the rotational movement of the rotatably movable frame allows the bowl poisoned above the casing to be separated from the casing.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

As shown inFIG. 1, a vertical centrifugal separator1of the present embodiment has a structure in which a vertical centrifugal separator main body3is attached to a frame2placed on a base (floor surface)11.

The frame2includes: a fixed frame21that is placed on and secured to the base11and to which a casing4of the centrifugal separator main body3is secured; and a movable frame22that is movable relative to the fixed frame21. The movable frame22includes: an upward-downward movable frame23disposed so as to be capable of being raised and lowered, i.e., to be movable upward and downward, relative to the fixed frame21; and a rotatably movable frame24disposed so as to be rotatably movable relative to the upward-downward movable frame23.

The fixed frame21has a hollow structure with a substantially prism shape and contains the upward-downward movable frame23thereinside in an upward-downward movable manner. The lower portion of the upward-downward movable frame23has a column shape and is moved upward and downward in the space inside the fixed frame21by a raising-lowering mechanism disposed inside the fixed frame21, which will be described later. The upper portion of the upward-downward movable frame23has a substantially circular shape in a plan view and is connected to the rotatably movable frame24through a support portion (not shown) that rotatably supports the rotatably movable frame24.

The rotatably movable frame24is detachably connected at its one end side to the upper portion of the casing4of the centrifugal separator main body3described later, and a main driving motor71is disposed on the other end side of the rotatably movable frame24. The substantially central portion of the rotatably movable frame24, i.e., a portion near its center of gravity, has a substantially circular shape in a plan view and serves as a connection portion rotatably connected to the support portion of the fixed frame21described above.

A first cylinder241for moving a wing driving motor73upward and downward relative to the rotatably movable frame24, a second cylinder242that is connected to the lower portion of the first cylinder241and provided to move upward and downward the position of a wing portion6used as a discharge assembly described later, and a brake243that abuts against the upper portion of a rotation shaft52of a bowl5described later to stop the rotation of the bowl5are further disposed on the one end side of the rotatably movable frame24. These cylinders241and242and the brake243are driven by actuators not shown.

A plurality of motors serving as driving means are disposed on the frame2. In the present embodiment, four motors are provided, which include the main driving motor71actuated during centrifugation of a solution being processed, a low-speed driving motor72actuated during washing of the centrifugal separator main body3, the wing driving motor73actuated during position adjustment of the bowl5and the wing portion6described later and during the operation for discharging solids produced during centrifugation, and a bowl removing motor74actuated during the operation for disassembling the bowl & wing assembly of the centrifugal separator.

Among these motors, the main driving motor71is attached to the rotatably movable frame24, and the driving shaft of the motor71protrudes from the upper and lower ends of the body of the motor. A pulley710is attached to the upper side of the driving shaft of the main driving motor71, and its driving force is transmitted to the bowl5through a driving belt711wound around the pulley710. The lower portion of the driving shaft of the main driving motor71faces the driving shaft of the low-speed driving motor72, and the end of the driving shaft of the main driving motor71has a shape fittable to the shape of the end of the driving shaft of the low-speed driving motor72.

The low-speed driving motor72is attached to the fixed frame21below the main driving motor71such that the driving shaft of the low-speed driving motor72is positioned coaxially with the driving shaft of the main driving motor71. The end of the driving shaft of the low-speed driving motor72has a shape fittable to the end of the driving shaft of the main driving motor71. The low-speed driving motor72is attached to a lifter211that moves upward and downward along the side surface of the fixed frame21. When the lifter211in the state shown inFIG. 1is moved upward by a not-shown actuator, the end of the driving shaft of the low-speed driving motor72is fitted to the end of the driving shaft of the main driving motor71, and these driving shafts are thereby coupled to each other. In this coupled state, when the low-speed driving motor72is driven to rotate, the driving force is transmitted to the bowl5through the driving shaft of the main driving motor71, the driving belt711, and the like.

The wing driving motor73is attached above the rotatably movable frame24through the first cylinder241and the second cylinder242such that the driving shaft of the wing driving motor73is positioned coaxially with a rotation shaft62of the wing portion6described later. The driving shaft of the wing driving motor73faces the upper end of the rotation shaft62of the wing portion6, and the end of the driving shaft of the motor73has a shape fittable to the upper end of the rotation shaft62of the wing portion6.

The bowl removing motor74transmits its driving force to the rotation shaft212of the raising-lowering mechanism provided inside the fixed frame21through a driving chain741and is disposed at the lower portion of the fixed frame21with the driving shaft of the motor74extending downward. A sprocket740engaging the driving chain741is provided to the driving shaft.

Next, a description will be giving of the raising-lowering mechanism for raising-lowering, i.e., moving upward and downward, the upward-downward movable frame23. The raising-lowering mechanism is configured to include the rotation shaft212, a protruding portion231protruding from the lower portion of the upward-downward movable frame23and attached to the rotation shaft212, and the bowl removing motor74for driving and rotating the rotation shaft212.

The rotation shaft212is a substantially cylindrical member, is disposed vertically inside the fixed frame21, and is rotationally supported inside the fixed frame21by a not-shown bearing and the like. The rotation shaft212has a not-shown thread groove portion formed on its surface and is driven to rotate by the bowl removing motor74through the driving chain741. A not-shown thread hole into which the thread groove portion of the rotation shaft212is screwed is formed also in the protruding portion231of the upward-downward movable frame23, and the protruding portion231is thereby installed to the rotation shaft212. Therefore, when the bowl removing motor74drives the rotation shaft212to rotate in a forward/backward direction, the upward-downward movable frame23integrated with the protruding portion231attached to the rotation shaft212moves upward/downward.

The centrifugal separator main body3includes the substantially cylindrical casing4connected integrally to the fixed frame21, the bowl5rotatably contained in the casing4, and the wing portion6rotatably contained in the bowl5and serving as a discharge assembly for discharging solids in the bowl5.

The casing4has a substantially cylindrical outer shape as a whole, and the bottom side of this shape is narrowed, so that a container-like (tank-like) inner shape is formed. The casing4is connected at its one end side to the fixed frame21by not-shown tightening bolts and the like, and a heavy-liquid discharge port43described later is provided at the other end side. A outlet44for an overflow is provided on the upper end side of the casing4. The outlet44can be used to allow a washing solution to overflow when, for example, the inside of the casing4is washed in dipping washing.

A detachable cover member41having a substantially circular shape in a plan view is attached to the lower portion of the casing4, and a feed tube42for supplying the solution to be processed and the washing solution is disposed at the center of the cover41. A drain port411for discharging the washing solution, which will be described later, used for washing and scrap materials and the like (such as residues of the processed solution) in the bowl5is provided near the feed tube42. The heavy-liquid discharge port43for discharging a heavy liquid produced and separated when the solution to be processed is centrifuged is disposed on the upper side of the casing4so as to protrude toward the outside of the casing4.

The one end side of the rotatably movable frame24is detachably disposed on the upper surface of the casing4. More specifically, a lower portion of main bearing housing244for covering the top portion of the casing4is formed on the one end side of the rotatably movable frame24. The lower portion of main bearing housing244has a substantially circular disc shape with an outer diameter greater than the outer diameter of the bowl5. A light-liquid discharge outlet25for discharging a light liquid produced and separated when the solution to be processed is centrifuged is provided in the lower portion of main bearing housing244so as to be in communication with the upper portion of the bowl5. In the present embodiment, the casing4is secured to the fixed frame21, and the rotatably movable frame24moves upward and downward together with the raising-lowering movement of the upward-downward movable frame23. Therefore, when the rotatably movable frame24moves upward, the bowl5and the wing portion6move upward and are thereby pulled out of the casing4.

The bowl5includes a bowl shell51to which the solution to be processed is supplied and the rotation shaft52provided integrally above the bowl shell51and rotatably supported by the rotatably movable frame24.

The bowl shell51has a substantially cylindrical tank-like shape smaller than the casing4, and a bowl bottom510is detachably attached to the bottom of the bowl shell51by not-shown securing means such as bolts. The bowl bottom510has a substantially annular shape in a plan view. The feed tube42described above is inserted into the center of the bowl bottom510, and a substantially circular hole510afor discharging the solids (a cake) in the bowl5is formed at the center of the bowl bottom510. The bowl bottom510has a cross sectional shape inclined toward the hole510aas shown inFIG. 2to facilitate a function of the bowl bottom510, i.e., the discharge of the solids (cake) in the bowl5. The rotation shaft52for driving the bowl shell51to rotate is provided integrally at the upper portion of the bowl5. The rotation shaft52of the bowl5is rotatably supported on the one end side of the rotatably movable frame24through a bearing mechanism521such as bearings. A hollow rotation support portion520is formed in the central portion of the rotation shaft52of the bowl5to rotatably support the wing portion6.

As shown inFIGS. 2 and 3, the wing portion6includes: a wing assembly61having a structure in which a plurality of plate-shaped wings612are formed so as to protrude from a shaft611serving as a rotation center; and the rotation shaft62that is disposed coaxially with the shaft611and protrudes upward from the wing assembly61. In the present embodiment, four wings612having the same shape are provided such that adjacent wings form an angle of 90°, and the outer portion of each wing has a shape twisted in a clockwise direction in a plan view. When the rotation shaft62of the wing portion6is inserted into the rotation support portion520in the rotation shaft52of the bowl5described above, the entire wing portion6is supported rotatably relative to the bowl5and the rotatably movable frame24.

The wings612of the wing portion6form an outer shape having a diameter slightly smaller than the inner diameter of the bowl5so that the wings612can rotate inside the bowl5relative to the bowl5. In the present embodiment, to allow the wing portion6and the bowl5coupled to each other to rotate integrally, an engagement portion is formed on the lower side of the wing portion6, and also an engagement portion is formed on the lower side of the bowl5. These engagement portions will next be described in detail.

In the vertical centrifugal separator1, the bowl5and the wing portion6have their respective engagement portions that are engaged/disengaged when the bowl5and the wing portion6are relatively moved in an axial direction, i.e., an upward/downward direction. In the present embodiment, as shown inFIGS. 2 and 3, a tapered portion511formed such that its inner diameter increases toward the end of the bowl5, i.e., in a downward direction, is provided in the lower portion of the inner wall of the bowl5. Each of the four wings612of the wing portion6has a tapered portion613formed in its outer lower portion and shaped such that the outer radial width of each wing612increases toward the end of the bowl5, i.e., in the downward direction. The tapered portion613of each wing612has a shape that substantially conforms to the shape of the tapered portion511of the bowl5. More specifically, the diameter of the outer shape formed by the outer lower portions of the wings612is slightly smaller than the diameter of the tapered portion511of the bowl5when the wing assembly61is located at the lowermost position, and therefore the wings612do not interfere with the inner wall of the bowl5. When the wing portion6moves upward, the tapered portion613of each of the wings612abuts against the tapered portion511of the bowl5. Then each of the wings612is engaged with the inner wall of the bowl5, so that the bowl5and the wing portion6are temporarily coupled to each other. In the vertical centrifugal separator1provided with such engagement portions, when the wing portion6is pulled upward, the bowl5and the wing portion6are engaged with each other, and these members (5and6) are secured to each other during the centrifugal operation for the solution to be processed and are allowed to rotate integrally at high speed.

Referring next toFIG. 3, the structure for washing the inside of the bowl5will be described. As shown inFIG. 3, the feed tube42has a double tube structure in which a outer tube422for the liquid feeding is disposed outside of the inner tube421for the washing feeding. As shown inFIG. 3(b) when the centrifugal operation is in feed mode, the liquid is supplied by feed port422aand jetted from nozzle422cthrough a space422bbetween outer tube422and inner tube421. The washing solution is supplied by supply port421aand jetted from a nozzle421cthrough an inner tube421when the centrifuge operation is in CIP mode.

An inner tube614for the passage of the washing solution is provided in the shaft611of the wing portion6. The inner tube614is formed so as to extend from the lower end side of the shaft611of the wing assembly61to its upper portion side. The lower end side of the shaft611in communication with the inner tube614is connected to or disposed near the washing solution spray nozzle421cof the feed tube42and serves as a connection portion611ahaving a recessed shape corresponding to the outer shape of the washing solution spray nozzle421c. As shown inFIG. 3, each wing612of the wing portion6is cut near the connection portion611ato form a substantially “L”-shaped notch so that the wing612does not interfere with the end of the feed tube42.

In the wing assembly61of the wing portion6, a plurality of nozzles615are disposed on the shaft611so as to be in communication with the inner tube614. The nozzles615include: horizontal spray nozzle616for jetting the washing solution in a lateral direction, i.e., toward the outer side of the wings612, at high pressure; and vertical spray nozzle617for jetting the washing solution in a longitudinal direction, i.e., toward the upper and lower sides of the wings612, at high pressure. The horizontal spray nozzle616and the vertical spray nozzle617are disposed such that the washing solution jetted therefrom is directed to one side of each wing. The jetting port of each of the horizontal spray nozzle616and the vertical spray nozzle617has a flattened shape so that the supplied washing solution is jetted so as to be spread in a planar fashion.

A plurality of horizontal spray nozzles616(for example, 6 nozzles for each wing) is disposed on the shaft611of the wing assembly61at predetermined intervals. Preferably, the horizontal spray nozzles616are disposed at intervals that cause the washing solution jetted from one nozzle and the washing solution jetted from another nozzle to overlap slightly as shown inFIG. 3(a). The vertical spray nozzles617are disposed on the shaft611of the wing assembly61such that one nozzle is oriented toward the upper side of one wing and another nozzle is oriented toward the lower side of the one wing (i.e., two nozzles are provided for one wing). The vertical spray nozzles617are disposed at positions at which the jetting direction of the washing solution does not interfere with the emission directions of the washing solution jetted from the horizontal spray nozzles616.

In the present embodiment, the horizontal spray nozzles616and the vertical spray nozzles617are disposed on the shaft611such that one row of nozzles616and one row of nozzles617are provided for each wing. More specifically, since four wings612are provided for the structure in the present embodiment, four rows of horizontal spray nozzles616and four rows of vertical spray nozzles617(a total of 32 nozzles) are disposed.

When the feed liquid is supplied through the feed tube42, this solution is jetted so as to be spread outward by the inclined surface of the connection portion611aas shown inFIG. 3(b) and is then supplied to the bowl5. When the washing solution urged at a predetermined pressure is supplied to the feed tube42during washing, the washing solution flows upward from one end side of the inner tube614of the shaft611of the wing portion6as shown inFIG. 3(a) and then jetted from the nozzles616and617in communication with the inner tube614at high pressure. During washing, the washing solution jetted from the nozzles616and617impinges strongly on the near-outer edge portion of each wing612at a predetermined angle, is then reflected from the each wing612, and impinges on the inner wall of the bowl5.

No particular limitation is imposed on the type and number of the horizontal spray nozzle616and the vertical spray nozzle617, and the type and the number may be appropriately changed according to the jetting direction of the washing solution from each nozzle (the spreading angle), the size of each wing, and other factors. It is not always necessary to provide both the horizontal spray nozzle616and the vertical spray nozzle617.

The vertical centrifugal separator1further includes a position adjustment mechanism for adjusting the phase between the wing portion6and the bowl5relative to the rotation axis to, for example, a single relative position relative to the rotation axis. The position adjustment mechanism is configured to include a plurality of groove portions and a plurality of protruding portions fittable to the groove portions, the groove portions and protruding portions being formed on the upper sides of the rotation shafts62and52of the wing portion6and the bowl5, respectively. When the rotation shafts62and52are rotated relative to each other, the fittable protruding portions are fitted into the corresponding groove portions, and the adjustment of the positions of the wing portion6and the bowl5relative to the rotation axis to the single relative position are thereby achieved. The position adjustment mechanism will next be described with reference toFIG. 4.

In the present embodiment, the position adjustment mechanism includes an index ring53secured to the upper end of the rotation shaft52of the bowl5and an inner ring63disposed on the wing portion6and fittable to the index ring53. The protruding portions are formed in the index ring53, and the groove portions are formed in the inner ring63.

The index ring53has a substantially annular shape in a plan view. A circular hole531in a plan view for inserting the rotation shaft62of the wing portion6is formed at the center of the index ring53, and a ring-shaped standing wall portion532in a plan view for inserting the side surface of the inner ring63is formed outside the hole531. As shown inFIG. 4(a), a plurality of protruding portions533,534, and535(at three positions in the present embodiment) are provided along the inner surface of the standing wall portion532of the index ring53. The angles between lines connecting the centers of the protruding portions to the center axis of the rotation shaft62(θ1, θ2, θ3) are different from each other. For example, these different angles are 100°, 120°, and 140°.

The inner ring63fittable to the index ring53is detachably attached near the upper end of the rotation shaft62of the wing portion6. The inner ring63has a substantially annular shape in a plan view with an outer diameter slightly smaller than the inner diameter of the index ring53, and a substantially circular hole631in a plan view for inserting the rotation shaft62of the wing portion6is formed at the center of the inner ring63. A notch631afor inserting a position adjustment projection (not shown) provided on the rotation shaft62of the wing portion6is provided in the hole631. The inner ring63has a flange portion632formed at one end, so that the lower portion of the inner ring63that faces the index ring53is formed to protrude outward. Groove portions633,634, and635(three groove portions in the present embodiment), the number of which are the same as the number of the protruding portions533,534, and535of the index ring53, are formed in the flange portion632of the inner ring63at positions corresponding to the protruding portions. More specifically, the angles between lines connecting the centers of the groove portions633,634, and635to the center axis of the rotation shaft62are the same as the different angles between the protruding portions533,534, and535, i.e., are 100°, 120°, and 140° in this example.

A coil spring54serving as urging means for urging the inner ring63and, in turn, the entire wing portion6upward is disposed between the index ring53and the inner ring63with the rotation shaft62of the wing portion6inserted into the coil spring54.

In the present embodiment configured as described above, when the inner ring63is stopped, the index ring53is rotated the rotation shaft62of the wing portion6while a force against the spring force of the coil spring54is applied to press the inner ring63toward the index ring53, the protruding portions533,534, and535of the index ring53are fitted into the groove portions633,634, and635of the inner ring63, respectively. Then the index ring53on the bowl5is engaged with the inner ring63on the wing portion6, and the positions of the bowl5and the wing portion6relative to the rotation shaft62are thereby adjusted to the single relative position.

Therefore, in the vertical centrifugal separator1, when the operation for centrifugation is started or detached members are re-attached after maintenance, the predetermined relative position between the bowl5and the wing portion6with respect to the rotation axis can be reproduced so that the dynamic balance during high-speed rotation is ensured. More specifically, when the bowl5and the wing portion6are rotated integrally during centrifugation and are rotated relative to each other during discharge of the cake and during washing as in the present embodiment, the positional relation between the bowl5and the wing portion6relative to the rotation axis when the relative rotation is stopped is not always the same as that when the bowl5and the wing portion6are rotated integrally. When high-speed rotation is performed, a slight imbalance due to, for example, production errors may cause vibrations, which may hinder stable high-speed rotation. Therefore, for example, the phase that minimizes vibrations is determined in advance by tests and the like. By adjusting the positions of the bowl5and the wing portion6always to positions giving the determined phase when the bowl5and the wing portion6are rotated integrally, the position adjustment in consideration of dynamic balance is achieved. In the above configuration, the spring that urges the index ring53and the inner ring63against each other is interposed therebetween. Therefore, when the force that presses the inner ring63toward the index ring53is released, the bowl5and the wing portion6are engaged with each other at the above-described engagement portions provided in the bowl5and the wing portion6while the predetermined positions of the bowl5and the wing portion6relative to the rotation axis are maintained. This can maintain the adjusted phase.

In the present invention, it is sufficient that the position adjustment mechanism is configured such that the positions of the wing portion6and the bowl5relative to the rotation axis can be adjusted to a single relative position that gives the best dynamic balance. However, the number of the single relative position is not necessarily one. A plurality of relative positions may be used so long as the dynamic balance is within an allowable range. In the present embodiment, the ring-shaped member having protruding portions is provided on the bowl5, and the ring-shaped member having groove portions fittable to the protruding portions is provided on the wing portion6. However, in contrast to the above configuration, groove portions may be provided for the bowl5, and protruding portions fittable to the groove portions may be provided for the wing portion6.

In the present embodiment, the numbers of the groove portions and protruding portions are 3. However, no particular limitation is imposed on these numbers. To allow the relative position between the wing portion6and the bowl5with respect to the rotation axis to be adjusted to a single relative position, it is preferable that, when a plurality of groove portions and projections are provided, the angles between adjacent groove portions and protruding portions with respect to the rotation axis be set to be different from each other, as described above. If the groove portions and protruding portions are disposed such that the angles between adjacent groove portions and protruding portions with respect to the rotation axis are the same, for example, three groove portions and three protruding portions are disposed at 120° intervals relative to the central axis, the effect described above can be obtained by arranging the groove portions and protruding portions such that the distances of the positions (phases) of the groove portions and protruding portions from the rotation axis are different from each other.

The operations of the vertical centrifugal separator1will next be described.

First, the basic operation of the vertical centrifugal separator1during centrifugation of the solution to be processed will be described. In the state shown inFIG. 1, the relative position of the entire wing portion6is raised by the urging force of the coil spring54, and the bowl5is engaged with the wing portion6. In the state shown in the figure, a not-shown actuator is driven to lower the first cylinder241. During this operation, the wing driving motor73is moved downward, and the driving shaft of the wing driving motor73is coupled to the rotation shaft62of the wing portion6. Next, a not-shown actuator is driven to lower the second cylinder242. During this operation, each of the wings612coupled to the tapered portion511in the lower portion of the bowl5is moved downward against the spring force of the coil spring54. Then the lower portion of the wing portion6is released from the bowl5, and the coupling between the wing portion6and the bowl5is thereby released.

Next, a not-shown actuator is driven to bring the brake243to an ON state, i.e., into abutment against the rotation shaft52of the bowl5. During this operation, the bowl5is secured to the rotatably movable frame24and to the casing4. When the wing driving motor73is driven while the bowl5is in the secured state, the entire wing portion6is rotated. Then the protruding portions533,534, and535of the index ring53in the above position adjustment mechanism are inserted into the groove portions633,634, and635of the inner ring63, respectively, and the inner ring63and the index ring53are engaged with each other at a predetermined position. The positions (phases) of the wing portion6and the bowl5relative to the axis are set to positions that allow high speed rotation while dynamic balance is taken into consideration.

Next, not-shown actuators are driven to raise the first cylinder241and the second cylinder242. During this operation, the entire wing portion6is moved upward by the urging force of the coil spring54. Then the tapered portion511of the bowl5and the tapered portions613of the wing portion6abut against each other and are engaged with each other, so that the wing portion6and the bowl5are secured to each other. In this case, the inner ring63is separated from the index ring53. However, the tapered portions613of the wing portion6and the tapered portion511of the bowl5are engaged with each other at positions that are set by the position adjustment mechanism described above and allow high speed rotation, and the bowl5and the wing portion6are allowed to rotate integrally.

Next, in the above state, the main driving motor71is driven. After the rotation speed of the motor71reaches a predetermined value, the solution to be processed is supplied from the feed tube42to the bowl5. During this operation, the wing portion6and the bowl5rotates integrally at high speed, and the solid-liquid separation of the supplied solution to be processed is started. Hereinafter, the bowl5and the wing portion6are collectively referred to as a “rotatable cylindrical body.” During high speed rotation, the rotation speed and centrifugal force of the rotatable cylindrical body are about 10,000 rpm and 20,000 G (twenty thousand G). However, the bowl5and the wing portion6are rotated integrally at the position in which the phase between them is set with the dynamic balance being taken into consideration, as described above. Therefore, in the vertical centrifugal separator1of the present embodiment, as the rotation speed of the rotatable cylindrical body increases, the stable center of the rotation is established, so that vibrations generated during centrifugation can be reduced although the vertical centrifugal separator1has the single-end supported structure. In addition, in the vertical centrifugal separator1of the present embodiment, the diameter of the bowl can be increased relative to that in a vertical centrifugal separator having a conventional both-end supported structure in which the vibrations generated during centrifugation are absorbed by upper and lower bearings.

Accordingly, in the vertical centrifugal separator1, when the solution to be processed is centrifuged, a light liquid separated by the action of very strong centrifugal force is discharged from the uppermost light-liquid discharge outlet25, and a heavy liquid is discharged from the lower heavy-liquid discharge port43. The separated solids (cake) are accumulated in the rotatable cylindrical body.

When a predetermined amount of solids (for example, about 40 L) is accumulated in the bowl assembly, the supply of the solution to be processed is stopped. Then the operation of the main driving motor71is stopped to stop the rotation of the rotatable cylindrical body, and the solid-liquid separation operation is thereby ended.

A description will next be given of the operation during discharge of the solids accumulated in the rotatable cylindrical body and other operations. In the state in which the rotatably cylinder is stopped as described above, a not-shown actuator is driven to lower the first cylinder241. During this operation, the driving shaft of the wing driving motor73is coupled to the rotation shaft62of the wing portion6.

Next, a not-shown actuator is driven to lower the second cylinder242. Then the wing portion6is lowered, and the wings612are thereby released from the bowl5, so that the engagement state between the bowl5and the wing portion6is released.

Next, the cover41provided with the feed tube42is detached from the casing4. The solids accumulated in the rotatable cylindrical body can thereby be discharged from the opened hole510a.

Next, a not-shown actuator is driven to bring the brake243to an ON state, i.e., into abutment against the rotation shaft52of the bowl5. During this operation, the bowl5is secured to the rotatably movable frame24and to the casing4. In the state in which the bowl5is secured, the wing driving motor73is driven, and only the wing portion6is rotated in a predetermined direction (an anticlockwise direction in a plan view in the present embodiment). The solids accumulated in the bowl5are thereby scraped off by the wings612of the wing portion6and discharged to the outside from the hole510aof the bowl shell51. The discharged solids fall to the outside from the lower side of the casing4from which the cover41has been detached.

Therefore, in the vertical centrifugal separator1in the present embodiment, the solids produced during centrifugation processing and accumulated in the bowl5can be automatically discharged without detaching the bowl5from the casing4. When the viscosity of the solids (cake) is high and the torque of the wing driving motor73becomes excessively high, the washing solution is jetted from the spray nozzle616and617before or while the wing portion6is rotated, so that the discharge of the solids can be facilitated. When the target material is the separated solution, the washing solution may be jetted in a similar manner to facilitate the discharge of the solids.

In other words, by the above-described operation of the vertical centrifugal separator1, the solids are removed from the bowl5completely or as completely as possible. Therefore, the time, cost, and the like required to wash the inside of the bowl5after the above operation are significantly reduced. More specifically, the bowl5need not be detached from the casing4. For some types of solutions to be processed or for the purpose of maintenance, the bowl5must be detached from the casing4to further wash the inside of the bowl5. Even in such a case, the time and cost required to complete washing are significantly reduced. Therefore, the time and cost required to complete washing when, for example, a food or chemical is used as the solution to be processed are significantly reduced as compared to those in the conventional vertical centrifugal separator.

A description will next be given of the procedure during washing of the bowl5, the operation of the vertical centrifugal separator1, and the like. First, the cover41provided with the feed tube42that has been detached before discharge is attached to the casing4. Next, a not-shown actuator is driven to raise the lifter211from the position shown inFIG. 1. During this operation, the driving shaft of the low-speed driving motor72raised together with the lifter211is engaged with and connected to the lower-side driving shaft of the main driving motor71.

Then the bowl5is rotated by the low-speed driving motor72at low rotation speed while the washing solution is urged and supplied to the feed tube42to wash the bowl5. During washing, the rotation of the wing portion6is stopped, and the brake243is brought to an OFF (release) state, so that only the bowl5is rotated. The washing solution is thereby jetted from the nozzles616and617of the wing portion6at high pressure. The jetted washing solution then impinges strongly on the wings612, and the washing solution impinging on the wings612is reflected and then impinges on the inner surface of the bowl5, so that the inside of the rotatable cylindrical body is automatically washed. During washing, the remaining solids that have not been removed during the automatic discharge described above, particularly the remaining solids adhering to the wings612and the inner wall of the bowl5, are well washed off by the physical and chemical actions of the washing solution urged and supplied. These solids are removed from the bowl5together with the washing solution and are discharged to the outside of the casing4from the drain port411.

In the vertical centrifugal separator1provided with the above-described washing mechanism in the present embodiment, the time required to wash the inside of the bowl is significantly reduced as compared to that in a vertical centrifugal separator that uses a conventional water-sealed method, i.e., a method in which the washing solution is supplied to the inside of the bowl to wash the inside of the bowl while the bowl is rotated under water sealed conditions. More specifically, although it takes about 30 minutes to complete washing in the conventional vertical centrifugal separator using the water sealed method, the washing of the inside of the bowl can be completed in about 5 minutes in the present embodiment.

After completion of the washing operation, a not-shown actuator is driven to lower the lifter211, and the connection between the driving shaft of the low-speed driving motor72and the lower-side driving shaft of the main driving motor71is thereby released.

For the purpose of regular maintenance or for some types of solutions to be processed, the bowl5and the wing portion6must finally be detached from the casing4, disassembled, and washed. The procedure of disassembling the bowl assembly, the operation of the vertical centrifugal separator1during disassembling, and the like will next be described with reference toFIG. 5.

First, in the state shown inFIG. 5(a), the bowl removing motor74is driven in a predetermined direction, and the rotation shaft212in the above-described raising-lowering mechanism is thereby rotated to raise the upward-downward movable frame23and the rotatably movable frame24integrally. During this operation, the bowl assembly composed of the wing portion6and the bowl5attached to the rotatably movable frame24is raised and pulled upward out of the casing4, as shown inFIG. 5(b).

Next, in the state shown inFIG. 5(b), a not-shown actuator is driven to move the rotatably movable frame24rotation ally relative to the upward-downward movable frame23by a predetermined angle, or 90° in an anticlockwise direction in a plan view in the present embodiment. During this operation, the bowl assembly positioned above the casing4is separated from the casing4as shown inFIG. 5(c), so that no other members are present below the bowl assembly.

Then, in the state shown inFIG. 5(c), the bowl removing motor74is driven in the direction opposite to the direction during the raising operation. The upward-downward movable frame23and the rotatably movable frame24are thereby lowered integrally, and the level of the upper portion of the bowl assembly coincides with the level of the casing4, as shown inFIG. 5(d). In the state shown inFIG. 5(d), the bowl bottom510is detached from the bowl shell51, and the inner ring63is detached from the rotation shaft62of the wing portion6. Then the wing portion6is pulled off downward, as shown inFIG. 5(e). Therefore, the wing portion6and the inner wall of the bowl5can be washed thereafter.

As described above, in the structure of the vertical centrifugal separator1of the present embodiment, the fixed frame21and the casing4are integrated, and the upward-downward movable frame23is disposed so as to be raised and lowered relative to the fixed frame21. In addition, the rotatably movable frame24is disposed so as to be rotatable relative to the upward-downward movable frame23, and the bowl5is disposed so as to be rotatable relative to the rotatably movable frame24. When the upward-downward movable frame23is raised, the rotatably movable frame24and the bowl5are raised integrally to allow the bowl5to be pulled upward out of the casing4. The rotational movement of the rotatably movable frame24allows the bowl5located above the casing4to be separated from the casing4. Therefore, the bowl assembly can be simply and rapidly disassembled.

In the embodiment described above, the washing mechanisms for washing the bowl5is configured to include the nozzles615(the horizontal spray nozzle616and the vertical spray nozzle617) that are arranged such that the washing solution is jetted toward one side of each of the wings612. An alternative embodiment may be configured such that the nozzles615(the horizontal spray nozzle616and/or the vertical spray nozzle617) are arranged such that the washing solution is jetted toward both sides (both the front and rear sides) of each of the wings612. In such a configuration, for example, additional horizontal spray nozzle616for washing adjacent wings may be disposed between the six horizontal spray nozzle616shown inFIG. 3(a). With this configuration, the time required to wash the inside of the bowl can be further reduced.FIG. 6shows another example of the wing assembly61. More specifically, the wing assembly61shown inFIG. 6has a structure in which three wings612protrude from the shaft611, and horizontal spray nozzle616that change their orientations alternately are disposed such that the washing solution is jetted toward both sides (both the front and rear sides) of each of the wings612.

Second Embodiment

A second embodiment of the present invention will next be described in detail with reference the accompanying drawings. The configuration in the present embodiment is similar to that in the first embodiment except that a structure suitable for reducing the size of the apparatus and a structure allowing washing under water sealed conditions are provided. Therefore, in the structure of the vertical centrifugal separator1in the present embodiment, as in that in the first embodiment, stable high-speed rotation that gives a centrifugal force of about 20,000 G can be achieved. In addition, the centrifuged solids can be efficiently discharged, and washing can be performed efficiently.

Therefore, the same components as those in the vertical centrifugal separator1in the first embodiment are designated by the same reference numerals, and their detailed description is omitted. Components whose positions and the like are changed due to the change in the structure are considered the same as those in the vertical centrifugal separator1in the first embodiment when their functions and actions are the same as those in the first embodiment.

The structure suitable for reducing the size of the apparatus is configured such that the bowl5can be removed from the lower side of the casing4. In the vertical centrifugal separator1in the first embodiment, the apparatus is automatically disassembled as shown inFIG. 5, and the bowl5is removed from the upper side of the casing4. Therefore, a space with a length equal to or larger than the length of the bowl5must be provided on the upper side of the apparatus. The structure in the first embodiment that allows the bowl5to be automatically removed from the casing4is advantageous in that the load on the operator, for example, can be reduced, but the space occupied by the apparatus is large. When the apparatus is used in the fields of food and medicine, the apparatus is installed in, for example, a clean room, and only a limited space is allocated for the apparatus. Therefore, in some cases, a reduction in size of the apparatus is required.

Accordingly, in the structure in the second embodiment, the casing4is divided into an upper casing4A and a lower casing4B as shown inFIG. 7, and the upper and lower casings4A and4B are detachably connected at their connection portions4C using securing means such as a clamp. Therefore, when the lower casing4B is detached, the lower portion of the bowl5is exposed. When the operator, for example, pulls downward off the rotatable cylindrical body (i.e., the bowl5and the wing portion6) together with the rotation shafts52and62, the bowl5and the wing portion6can be detached. In the above structure, the virtual occupation space of the apparatus can be reduced as compared to that when the bowl5is lifted upward, and therefore the size of the apparatus can be reduced. In addition, the movable frame22for automatically removing the bowl5from the lower casing4B and the driving mechanism for the movable frame22, as exemplified inFIG. 1, can be omitted, and only the fixed frame21is required to be provided. The size of the apparatus is reduced accordingly, and the cost of the facility is reduced. When the apparatus is disassembled for maintenance, for example, the lower casing4B is detached, and the upper casing4A is detached from the connection part between the lower portion of main bearing housing244and the upper casing4A. Then the wing portion6is detached together with the rotation shaft62, and the bowl5can be thereby detached together with the rotation shaft52.

The lower casing4B in the present embodiment has a shape with a bottom inclined in one direction, and an openable-closable door45(such as a man-hole) is provided at the front end surface of the lower casing4B. In such a case, when a predetermined amount of solids (cake) is accumulated in the bowl5during centrifugation, the wing portion6is driven by the wing driving motor73to discharge the solids from the bowl5, and then centrifugation is continued or resumed after washing. When a certain amount of discharged materials (the solids and washing solution) is accumulated in the lower casing4B during continuous centrifugation, the door45is opened to discharge the solids and the like from the casing4. Such continuous centrifugation allows a reduction in the total processing time as compared to that when the solids are discharged from the casing4after each centrifugation operation.

In the vertical centrifugal separator1in the present embodiment, the structure suitable for reducing the size of the apparatus uses a bearing in the bearing mechanism521for rotatably supporting the rotation shaft52of the bowl5and employs a method of automatically injecting lubricating grease into the bearing. In this manner, for example, even when the diameter of the bowl5is reduced to reduce the size of the apparatus, high-speed rotation can be maintained.

More specifically, to achieve the centrifugal force using a bowl5with a reduced diameter, the rotation speed of the bowl5must be increased by an amount corresponding to the reduction in diameter. For example, to achieve a centrifugal force of about 20,000 G using a bowl5with a diameter of 14 inches, the rotation speed must be about 10,000 rpm. To achieve a centrifugal force of about 20,000 G using a bowl5with a diameter of 10 inches, the rotation speed must be about 12,000 rpm. However, the load on the bearing in the bearing mechanism521increases by an amount corresponding to the increase in the rotation speed of the bowl5. In some bearings, such a rotation speed exceeds the permissible rotation speed in their specifications.

Therefore, in the present embodiment, a plurality of ball bearings8are arranged in the axial direction of the rotation shaft52, and an injection hole81for injecting lubricating grease is formed for each of the ball bearings8, as shown inFIG. 8. A ring-shaped member (so-called spacer)82is disposed between adjacent bearings to form a reservoir space821for reserving the grease in the spacer82. The reservoir spaces821formed in the spacers82are used to reserve excess grease discharged from the ball bearings8when additional grease is fed. Each spacer82includes an inner spacer82A and an outer spacer82B fitted to each other, and a groove portion (not shown) for discharging the grease from the inside of a bearing to the reservoir space821is formed in the outer spacer82B. This groove portion is formed in consideration of the direction of the bearing and other factors so that the grease once discharged to the reservoir space821is prevented from re-entering the inside of the bearing. By preventing unnecessary grease from re-entering the inside of the bearing as described above, an increase in temperature of the bearing can be prevented. Grease supply passages83such as pipes or tubes are connected to the injection holes81of the ball bearings8, and a grease supply tank84is connected to the base end side of the grease supply passages83. Five ball bearings8are disposed along the rotation shaft52inFIG. 7. However, no limitation is imposed on the number of ball bearings8.

A gas supply passage85such as a pipe or tube for supplying a gas (such as air or nitrogen) for pressurization and extrusion of the grease is further connected to the grease supply tank84, and a gas supply source86such as a compressor or a tank is connected to the base end side of the gas supply passage85. The gas supply passage85includes two lines for tank pressurization and for grease extrusion, and open-close valves851and852are provided in these two lines, respectively. Therefore, when the open-close valve852is opened to increase the pressure inside the grease supply tank84and then the open-close valve851is instantaneously opened to drive like a piston, the grease is extruded into the grease supply passages83, and substantially equal amounts of grease are fed into the respective ball bearings8. The amount of grease injected can be controlled by the opening time of the open-close valve851and the pressure for pressurization. The opening timing of the open-close valve851can be controlled by, for example, a sequence program installed in a not-shown controller.

In the above configuration, the ball bearings8(except for the reservoir spaces821) are filled with the required amount of grease in advance, and centrifugation is performed in the procedure described above. In this manner, the apparatus is maintenance free for more than a year. During this period, a predetermined amount of grease is fed at regular time intervals, and excess (unnecessary) grease is reserved in the reservoir spaces821until the apparatus is disassembled at the next maintenance. In a preferred example, about 0.02 cc of grease is fed into each of the ball bearings8once a day just after the start of operation, and the grease accumulated in the spaces is removed when maintenance is performed in a period of one year.

When the apparatus is used for a food or medicine, a grease is selected as the lubricant for the ball bearings8because impurities mixed may cause problems. However, when a grease is used, it is not possible to check, after the ball bearings8are filled with a predetermined amount of grease and the apparatus is assembled, whether or not the required amount of grease remains in the ball bearings8unless the apparatus is subsequently disassembled. Therefore, a problem arises as to whether or not seizing of the rotation shaft52can be prevented when a bowl5with a reduced diameter is used and the rotation speed is increased. In the configuration of this embodiment, a small amount of grease is regularly injected, and the excess grease is discharged and prevented from re-entry. In this manner, the amount of grease in the ball bearings8can be optimally maintained, and an increase in temperature of the bearings during supply of the grease can be prevented.

Therefore, since the seizing problem and the like can be prevented even at higher rotation speed, the diameter of the bowl5can be reduced, and the size of the apparatus can thereby be reduced. This is also advantageous for the operator because the labor for maintenance is reduced. Of course, a higher centrifugal force can be obtained by increasing the rotation speed of the bowl5without changing the diameter of the bowl5. The structure of the ball bearings8shown inFIG. 8may be used for the vertical centrifugal separator1in the first embodiment shown inFIG. 1.

The vertical centrifugal separator1in the present embodiment has a structure suitable for washing under water sealed conditions, in addition to the structure suitable for reducing the size of the apparatus. In this structure, washing under water sealed conditions can be performed in addition to washing using the spray nozzle616and617described above. This allows the casing4and the rotatable cylindrical body (the bowl5and the wing portion6) to be kept clean in a more reliable manner. The vertical centrifugal separator1of the present embodiment is configured such that washing under water sealed conditions can be performed before, after, or simultaneously with the above-described washing using the spray nozzle616and617.

As shown inFIG. 7or9, the wing assembly61shown inFIG. 6has been installed in the vertical centrifugal separator1of the present embodiment. In contrast to the first embodiment in which the washing solution is supplied through the feed tube42disposed on the lower side, the inner tube614used as the supply passage of the washing solution is extended to the upper end of the shaft611to supply the washing solution from the upper side. Therefore, an inner tube used as the supply passage of the washing solution is also formed in the driving shaft rotated by the wing driving motor73, and the washing solution is supplied after the shaft611and the driving shaft are coupled to each other by the first cylinder241. In the present embodiment, the position of the wing driving motor73is changed, and the rotation shaft is driven by a couple gears.

When operating in dipping washing, the casing4must be hermetic. Generally, a known sealing material such as an O-ring or gasket can be used as the sealing material disposed at each of the connection portions/coupled portions of the casing4. No limitation is imposed on the type of the sealing material, so long as sufficient sealing properties are ensured. However, for example, when the number of parts increases, sufficient sealing properties may not be ensured due to the influence of production errors and other factors. Therefore, a sealing member91formed into a tubular shape using an elastic material such as rubber is used as a sealing material9that is disposed at a position at which the sealing properties are of particular importance, for example, at the connection portion between the lower portion of main bearing housing244of the casing4and the upper casing4A shown inFIG. 9. In addition, a tube92for urging and supplying a fluid for pressurization (such as air or nitrogen) to the inside of the sealing member91is connected, and a fluid source (not shown) such as a compressor or a steel bottle is connected to the base end of the tube92. An open-close valve (not shown) is provided at a midway of the tube92. For example, the open-close valve is opened at all time to urge and supply the fluid for pressurization to the sealing member91. The sealing member91is thereby expanded in the groove portion, and the gap in the connection portion is eliminated and sealed.

With the hermeticity of the casing4being ensured as described above, outlets such as the heavy-liquid discharge port43are closed, and the washing solution is jetted from, for example, the spray nozzle616and617as described above. The inner surface of the bowl5and the wing portion6are thereby washed, and the washing solution is accumulated in the casing4. The washing under water sealed conditions is continued until the washing solution is accumulated to a level at which the washing solution is discharged from the outlet44for an overflow. In this manner, particularly, the outer surface of the bowl5and the inner surface of the casing4that cannot be sufficiently washed using the spray nozzle616and617can be washed. In this case, a valve may be provided at the outlet of the outlet44to control the discharged amount or the supply pressure of the washing solution may be increased so that the washing solution reaches the inner upper surface of the casing4. To wash the inner upper surface and upper corners of the casing4that are likely to become dead spaces, spray nozzle618, for example, may be disposed at positions shown inFIG. 9.

In the vertical centrifugal separator1of the present embodiment, the low-speed driving motor72and the lifter211in the first embodiment are omitted, and the bowl is rotated during washing by the main driving motor71. More specifically, this embodiment includes two motors71and73for driving the main body and driving the wings.

While the present invention has been described in detail in conjunction with specific embodiments, it is apparent to persons of ordinary knowledge in this technological field that various substitutions, modifications, changes, and the like to the forms and details can be made without departing from the spirit and scope of the invention that are defined in the description of claims. Therefore, the scope of the invention is not limited to the above-described embodiments and the accompanying drawings but should be defined by the claims and their equivalents.

DESCRIPTION OF REFERENCE NUMERALS