centrifuge

Abstract

The present disclosure relates to a centrifuge including a rotor (4) having a rotor body (8) with an outlet opening (10) and a slide (30) disposed within the rotor body (8) for closing the outlet opening (10). A working chamber (32) is disposed between the axially movable slide (30) and the rotor body (8) for receiving a working fluid for displacing the slide (30). A working fluid discharge channel (34) extends from the working chamber (32) to an exterior space (36) within the rotor body (8). A pilot valve (40) is disposed in the rotor body (8) for opening and closing the working fluid discharge channel (34), and a control fluid channel (46) extends to the pilot valve (40) to supply control fluid thereto. A portion (46') of the control fluid channel (46) extends through the valve body (42).

Description

[Technical Field]

[0001] The present invention relates to a centrifuge. [Background technology]

[0002] Various types of continuously operating centrifuges are known for separating solids and / or sludge from liquids or liquid mixtures. High-speed centrifuges include a rotor that rotates about a vertical axis of rotation while the separator is in use. One type of centrifuge is designed to discharge solids and / or sludge intermittently.

[0003] The solids and / or fine particles comprising the liquid or liquid mixture to be separated are introduced into the separation space of the rotor while the rotor is rotating, and the solids, fine particles and / or sludge are carried by centrifugal force towards the periphery of the separation space, through which they are discharged from the separation space in the body of the rotor through an outlet opening.

[0004] Opening and closing of the outlet opening from the separation space is controlled by an axially movable slide that forms the lower limit of the separation space. The axially movable slide may be referred to as a sliding bowl bottom, a piston valve, or the like. A pilot valve may be used to control the axially movable slide. The pilot valve is smaller and requires less force to operate compared to the axially movable slide.

[0005] For example, as disclosed in DE 3133689, the rotor includes a piston valve slidably mounted in its lower portion in the axial direction, which closes the outlet opening in the upper position and opens the outlet opening in the lower position. A closing chamber below the piston valve is filled with a liquid called a closing liquid or sealing liquid to move or maintain the piston valve in its upper position. When the closing chamber is emptied of the closing liquid, the piston valve moves to its lower position, thus opening the outlet opening. A fluid-driven centrifugal valve disposed in the rotor body is provided to empty the closing chamber. The fluid-driven centrifugal valve thus forms a pilot valve for the piston valve. An inlet conduit is connected to the centrifugal valve and configured to direct a control fluid to a valve cone of the centrifugal valve. The inlet conduit is connected to a longitudinal side of the centrifugal valve to supply the control fluid to the valve cone for radial movement toward the rotation axis.

[0006] When the rotor rotates, the centrifugal force acting on the valve cone exerts a force radially outward from the axis of rotation against it, keeping the discharge channel from the closed chamber closed. Therefore, the closing liquid in the closed chamber remains there. To open the piston valve and empty the closed chamber, a control fluid is directed to the valve cone and forced radially toward the axis of rotation against the centrifugal force. Therefore, the discharge channel from the closed chamber opens and the closing liquid is discharged from the closed chamber.

[0007] U.S. Pat. No. 4,410,317 discloses a self-draining centrifugal drum for a centrifuge of the type discussed above. Again, a closed compartment, which can be filled with a closing fluid, is located below the piston valve, and the closing fluid is supplied through a channel connected to the intermediate compartment relative to the closing fluid. The closed compartment is emptied by the centrifugal valve to initiate solids / sludge discharge. Again, the valve that empties the closed compartment is a centrifugal valve including a movable valve cone, which is actuated by a control fluid. The valve cone has a smaller diameter than the valve cone and a valve protrusion that is sealed in the drum jacket behind the valve cone. Therefore, when the valve cone moves to its open position, the valve protrusion extensively clogs or blocks the channel connecting the closed compartment to the intermediate compartment. Therefore, the channel located radially inside and concentric with the valve cone is filled with the closing fluid. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] DE3133689 [Patent Document 2] U.S. Patent No. 4,410,317 Summary of the Invention [Problem to be solved by the invention]

[0009] It would be advantageous to realize alternative arrangements for controlling the axially movable slide of a centrifuge. In particular, it would be desirable to enable precise control of the axially movable slide of a centrifuge. In order to better address one or more of these challenges, a centrifuge is provided having the features defined in the independent claims. [Means for solving the problem]

[0010] According to one aspect of the present invention, a centrifuge is provided that includes a rotor configured to rotate about a rotation axis having an axial extension, the rotor including a rotor body provided with an outlet opening disposed at the periphery of the rotor body, and an axially movable slide disposed within the rotor body for closing the outlet opening at a first axial position and for opening the outlet opening at a second axial position. A separation space is provided within the rotor, and at the second axial position of the axially movable slide, the outlet opening fluidly connects the separation space with an ambient space outside the rotor. A working chamber is provided between the axially movable slide and the rotor body for receiving a working fluid that displaces the axially movable slide from its second axial position to its first axial position. A working fluid discharge channel extends within the rotor body from the working chamber to a space external to the rotor. A pilot valve is disposed within the rotor body to open and close the working fluid discharge channel. A control fluid channel extends at least partially through the rotor body to the pilot valve for supplying control fluid to the pilot valve. The pilot valve includes a valve body having a longitudinal axis, the valve body being movable parallel to the longitudinal axis from a first radial position to a second radial position under the influence of a control fluid. A control fluid channel extends to an actuation pressure-receiving region of the valve body. A portion of the control fluid channel extends through the valve body to the actuation pressure-receiving region.

[0011] Because a portion of the control liquid channel extends through the valve body to the actuation pressure receiving area, the length of the control liquid channel through the valve body to the actuation pressure receiving area of ​​the valve body is kept short. Therefore, the overall volume of the control liquid channel is smaller than the volume of the corresponding control liquid channel that passes through the rotor body and leads laterally from the pilot valve to the actuation pressure receiving area of ​​the valve body. The small volume of the control liquid channel results in more responsive control of the pilot valve compared to one supplied with control liquid from a control liquid channel having a larger volume. Therefore, precise control of the pilot valve, and with it, precise control of the axially movable slide for opening and closing the outlet opening from the separation space, is achieved.

[0012] Furthermore, having a portion of the control liquid channel extending through the valve body means that this portion of the control liquid channel and the portion of the control liquid channel leading to it can extend in a straight line with respect to each other or at only a slight angle relative to each other. Fabrication of the control liquid channel is therefore easier than a control liquid channel that passes through the rotor body and leads laterally from the pilot valve to the actuation pressure-receiving region of the valve body. This latter type of control liquid channel would, for example, be drilled from multiple different directions through the rotor body, which would require plugging the portions of the drilled holes that form the control liquid channel.

[0013] If a portion of the control fluid channel extends through the valve body and the control fluid channel and the portion of the control fluid channel extend into that portion in a straight line or at only a slight angle, drilling the control fluid channel through the rotor body only needs to be done in one direction or a limited number of directions. Furthermore, no portion of the drilled hole needs to be plugged.

[0014] The centrifuge is a high speed centrifuge, i.e. the rotor rotates at several thousand revolutions per minute, such as 3000-12000 rpm, during use of the centrifuge.

[0015] The rotor may be disposed inside a stationary housing of the centrifuge and may be driven to rotate about an axis of rotation by a drive arrangement comprising, for example, an electric motor.

[0016] When the centrifuge is placed in use, the axial extension of the rotation axis may extend vertically, and the rotor may therefore have an upper portion and a lower portion.

[0017] As used herein, the terms axial, radial, and rotational relate to the axis of rotation. The axial direction extends parallel to the axis of rotation of the rotor, and the radial direction extends perpendicular to the axis of rotation. The rotational direction extends around the axis of rotation.

[0018] In this specification, an axially movable slide is also referred to as a slide. The first and second axial positions of the slide can be opposite axial end positions of the slide's range of motion.

[0019] The rotor body of the rotor may comprise one or more separation portions. The axially movable slide may define at least a portion of a lower portion of the separation space.

[0020] During use of the centrifuge, separation of the liquid feed mixture takes place in the separation space of the centrifuge, in which a separation aid, for example comprising a stack of frusto-conical separating discs, can be arranged.

[0021] During use of the centrifuge, the liquid compound feed is fed into the separation space along the rotation axis. The separated light phase is fed out of the separation space along the rotation axis or radially adjacent to the rotation axis. The sludge phase is separated from the liquid mixture and discharged through the outlet opening. According to some embodiments, the separated heavy phase can be fed out of the separation space along the rotation axis or radially adjacent to the rotation axis.

[0022] The sludge phase comprises a liquid with heavy solid particles and / or a liquid with heavy liquid particles of another liquid suspended therein, which separates into the peripheral portion of the separation space and is discharged from the separation space when the slide is in its second axial position, thus opening the outlet opening.

[0023] During use of the centrifuge, when the slide is in the second axial position, the sludge phase is discharged through the outlet opening into an ambient space outside the rotor, which may be provided between the rotor and the stationary housing of the centrifuge. The discharged sludge phase is then conveyed from the ambient space by suitable means.

[0024] During use of the centrifuge, when separation of liquid compound feed occurs, the axially movable slide is in its first axial position, thus closing the outlet opening. The slide is held in the first axial position by the working fluid in the working chamber. Intermittently, when the separated sludge phase is discharged from the separation space, the pilot valve opens. As a result, the working chamber at least partially empties the working fluid into the space outside the rotor via the working fluid discharge channel, and the slide moves to its second axial position, thus opening the outlet opening.

[0025] Depending on the duration the pilot valve is open, partial drainage of the contents of the separation space or complete drainage of the contents of the separation space is achieved. In partial drainage, some or all of the separated sludge phase is drained from the separation space. During partial drainage, a liquid interphase between the separated liquid phases of different densities within the separation space can be maintained. In complete drainage, the interface breaks down and must be re-formed after drainage is complete.

[0026] The slide is returned from the second axial position to the first axial position by closing the pilot valve and again filling the actuating chamber with actuating fluid.

[0027] Vice versa, movement of the slide between its first and second axial positions may not necessarily empty or fill the working chamber with working fluid. The slide moves to either the first or second axial position when a threshold pressure is reached in the working chamber. At the threshold pressure, the working fluid can partially fill the working chamber.

[0028] In a known manner, a source of actuating liquid can be connected to the working chamber. Furthermore, the actuating liquid discharge channel can be dimensioned such that when the actuating liquid discharge channel is open, the discharge of the actuating liquid discharge channel exceeds the inflow of actuating liquid. Thus, when the pilot valve opens to move the slide from its first axial position to its second axial position, the working chamber is more quickly drained via the actuating liquid discharge channel than refilled from the source of actuating liquid, but rapid refilling of the working chamber can be ensured as soon as the pilot valve closes.

[0029] The rotor external space can be located between the rotor and the stationary housing of the centrifuge, and can form part of the ambient space, so that the sludge phase and the working liquid can be discharged into the same space outside the rotor.

[0030] A pilot valve is a small valve compared to the valve formed by the axially movable slide. The pilot valve requires much less force to operate than the axially movable slide. The pilot valve utilizes a relatively small flow of control fluid to "pilot" the axially movable slide compared to the flow of actuating fluid utilized to open and close the valve slide.

[0031] During use of the centrifuge, when control fluid is supplied to the actuation pressure receiving area of ​​the valve body of the pilot valve, pressure builds up in a control chamber bordering the actuation pressure receiving area, and if the pressure is high enough in the control chamber, the pressure actuates the valve body through the actuation pressure receiving area, causing the valve body to be displaced from its first radial position to its second radial position and opening the actuation fluid discharge channel.

[0032] For clarity, the actuation pressure-receiving region of the valve body is the portion of the valve body that, when acted upon by the pressure of the control fluid, results in a force moving the valve body from its first radial position to its second radial position to open the pilot valve. Thus, viewed along the longitudinal axis radially inward from the pressure-receiving region, a space is provided. When the valve body is in its first radial position, the space is empty. When in its second position, the valve body is at least partially located within this space.

[0033] For example, the first radial location may be at a larger radius of the rotor than the second radial location.

[0034] The valve body can be configured such that centrifugal force returns the valve body to its first radial position to close the working fluid exhaust channel. Additionally or alternatively, the valve body can be biased toward its first radial position.

[0035] Control fluid is supplied to the pilot valve through the control fluid channel when the pilot valve is opened, thus moving the valve body from the first to the second radial position, and when the pilot valve is closed again, the supply of control fluid is stopped and the control chamber is drained of control fluid.

[0036] According to embodiments, the control fluid channel can extend partially through the valve body, concentric with the longitudinal axis of the valve body. In this manner, the control fluid channel upstream of the valve body can be in fluid communication with the portion of the control fluid channel extending through the valve body. This can contribute to a short, low-volume control fluid channel.

[0037] Additionally, this can provide a fluid connection to an actuation pressure receiving region that extends through the valve body, which again can contribute to a short and low volume control fluid channel.

[0038] Furthermore, a control fluid channel extending at least partially through the valve body, concentric with the longitudinal axis of the valve body, means that the control fluid channel can extend through the pressure-receiving region, such as concentrically with the pressure-receiving region, which contributes to efficient distribution of control fluid from the control fluid channel throughout the pressure-receiving region.

[0039] According to the embodiment, the guide member can guide the movement of the valve body between the first radial position and the second radial position, thereby ensuring that the valve body can be smoothly displaced between the first radial position and the second radial position.

[0040] For example, angular displacement of the valve body relative to an intended direction of movement parallel to the longitudinal axis can be avoided, thus preventing the valve body from accidentally becoming pinched within the bore through which the valve body moves between the first and second positions.

[0041] According to an embodiment, the guide member may be provided with a through-opening that fluidly connects the control liquid channel with the external space, the through-opening having a smaller cross-sectional area than the control liquid channel in the guide member. In this way, the control chamber in the actuation pressure receiving area may be vented through the guide member when the pilot valve is opened and then closed again. Furthermore, due to the smaller cross-sectional area of ​​the through-opening compared to that of the control liquid channel, the control chamber may be filled with control liquid, and the pressure therein may increase, affecting the actuation pressure receiving area, when the pilot valve is opened. That is, the smaller cross-sectional area forms a restriction for the control liquid to fill the control chamber.

[0042] According to an embodiment, a portion of the valve body at the first radial position can abut a sealing surface disposed on the rotor. The portion of the valve body and the sealing surface form a sealing interface for the working fluid discharge channel. In this manner, the pilot valve can be configured to seal against the working fluid discharge channel.

[0043] Further features of the present invention and its advantages will become apparent from the appended claims and from the detailed description that follows.

[0044] Various aspects and / or embodiments of the present invention, including its particular features and advantages, will be readily understood from the exemplary embodiments discussed in the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0045] [Figure 1] FIG. 1 is a schematic cross-sectional view of a centrifuge according to an embodiment. [Figure 2a] 1 is a schematic cross-sectional view of a portion of a centrifuge; [Figure 2b] 1 is a schematic cross-sectional view of a portion of a centrifuge; [Figure 3a] 1 is a schematic cross-sectional view of a pilot valve according to an embodiment. FIG. [Figure 3b] 1 is a schematic cross-sectional view of a pilot valve according to an embodiment. FIG. [Figure 4] 2 is a schematic cross-sectional view of a portion of a pilot valve 40 of a centrifuge according to an embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0046] Aspects and / or embodiments of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for the sake of brevity and / or clarity.

[0047] FIG. 1 shows a schematic cross section of a centrifuge 2 according to an embodiment.

[0048] The centrifuge 2 comprises a rotor 4 configured to rotate about a rotation axis 6. The rotation axis 6 has an axial extension. The rotor 4 comprises a rotor body 8 provided with an outlet opening 10, i.e., the outlet opening 10 extends through the rotor body 8. The outlet opening 10 is arranged around the periphery of the rotor body 8.

[0049] Separation spaces 12 are provided in the rotor 4. Outlet openings 10 are evenly distributed around the circumference of the rotor 4 and are configured for intermittent discharge of at least the sludge phase separated in the separation spaces 12.

[0050] The outlet opening 10 can be intermittently opened by the action of an axially movable slide (not shown) within the rotor 4, see below in conjunction with Figures 2a and 2b. When open, the outlet opening 10 fluidly connects the separation space 12 with an ambient space 14 outside the rotor 4.

[0051] The outlet opening 10 can be opened as needed and / or for equal time periods so that all, or part of the contents of the separation space 12 can be partially or completely evacuated.

[0052] A pilot valve 16 is arranged on the rotor body 8. The pilot valve 16 controls the movement of an axially movable slide and thus the opening and closing of the outlet opening 10, see further Figures 2a to 4 below.

[0053] A separation aid in the form of a stack 18 of frusto-conical separating discs is disposed in the separation space 12. Other types of separation aids, such as, for example, radially extending vanes, may alternatively be disposed in the separation space 12.

[0054] The rotor 4 is supported and driven by a spindle 20. The rotor 4 is rotatably disposed inside a stationary housing 22 of the centrifuge 2.

[0055] In these embodiments, the ambient space 14 is formed within a stationary housing 22. The sludge phase is directed out of the ambient space 14 via an outlet conduit, not shown.

[0056] The spindle 20 and rotor 4 are driven to rotate about the rotation axis 6 by a drive arrangement including an electric motor 24. In the illustrated embodiment, the spindle 20 is directly driven by the electric motor 24. In an alternative embodiment, a gearbox can be disposed between the electric motor and the spindle.

[0057] An inlet 26 for the liquid compound feed to be separated in the centrifuge 2, which leads into the separation space 12, is arranged at the upper end of the rotor 4. Alternatively, the liquid compound feed can be fed into the separation space 12 from below the rotor 4 via a hollow spindle.

[0058] An outlet 28 for the separated liquid light phase is located at the upper end of the rotor 4. Alternatively, the liquid light phase can be directed from the separation space via a hollow spindle below the rotor 4.

[0059] Optionally, a further outlet (not shown) for the separated heavy liquid phase may be provided, located at the upper or lower end of the rotor 4 .

[0060] Figures 2a and 2b show a schematic cross section of a portion of a centrifuge 2. The centrifuge 2 may be the centrifuge 2 discussed above with reference to Figure 1. Accordingly, the following references are also made to Figure 1.

[0061] Again, the centrifuge 2 comprises a rotor 4 arranged to rotate about a rotation axis 6. The rotor 4 comprises a rotor body 8 provided with an outlet opening 10. A separation space 12 is provided within the rotor 4.

[0062] An axially movable slide 30 is disposed within the rotor body 8. The slide 30 is configured to close the outlet opening 10 in a first axial position, as shown in Figure 2a, and to open the outlet opening 10 in a second axial position of the slide 30, as shown in Figure 2b.

[0063] In the first axial position, the slide 30 sealingly abuts at its periphery against the top of the rotor body 8 , thereby closing the separation space 12 from fluid connection with the outlet opening 10 and with the ambient space 14 outside the rotor 4 .

[0064] In the second axial position, the slide 30 is positioned such that the outlet opening 10 fluidly connects the separation space 12 with the ambient space 14 .

[0065] A working chamber 32 is provided between the slide 30 and the rotor body 8. In these embodiments, the working chamber 32 is provided below the slide 30, between the slide 30 and a lower portion of the rotor body 8. The working chamber 32 is configured to receive working fluid to displace the axially movable slide 30 from its second axial position to its first axial position. The working fluid may be supplied from a radially inner portion of the rotor 4 via a working fluid supply system.

[0066] The working fluid may be water.

[0067] A working fluid discharge channel 34 extends in the rotor body 8 from the working chamber 32 to an exterior space 36 of the rotor 4. The exterior space 36 may form part of the ambient space 14 or it may be separated from the ambient space 14.

[0068] The pilot valve 40 is configured on the rotor body 8 to open and close the working fluid discharge channel 34. The pilot valve 40 includes a valve body 42 that is movable relative to the rotor body 8. The valve body 42 has a longitudinal axis 44. The valve body 42 is movable parallel to the longitudinal axis 44 within the rotor body 8 from a first radial position to a second radial position. The first radial position of the valve body 42 is shown in FIG. 2a, when the slide 30 is in its first axial position. The second radial position of the valve body 42 is shown in FIG. 2b, when the slide 30 is in its second axial position.

[0069] Some aspects of the pilot valve 40 are also discussed below with reference to Figures 3a and 3b.

[0070] The first radial position of the valve body 42 is at a larger radius than the second radial position. The longitudinal axis 44 can extend radially, as in the illustrated embodiment. Alternatively, the longitudinal axis 44 can extend at an angle to the radial direction. Furthermore, the first radial position of the valve body 42 will be at a larger radius than the second radial position.

[0071] Thus, the valve body 42 is configured to move between a first radial position and a second radial position to open and close the actuating fluid exhaust channel 34. In the first radial position of the valve body 42, the actuating fluid exhaust channel 34 is closed and actuating fluid fills the actuating chamber 32 and the actuating fluid exhaust channel 34, at least to a significant extent. In the second radial position of the valve body 42, the actuating fluid exhaust channel 34 is open and actuating fluid is exhausted from the actuating chamber 32 and from the actuating fluid exhaust channel 34.

[0072] The control fluid affects movement of the valve body 42 at least in a direction from the first radial position to the second radial position.

[0073] The control liquid may be water.

[0074] A control fluid channel 46 extends at least partially through the rotor body 8 to the pilot valve 40 for supplying control fluid to the pilot valve 40. The control fluid channel 46 extends to an actuation pressure receiving area 48 of the valve body 42. A portion 46' of the control fluid channel 46 extends through the valve body 42 to the actuation pressure receiving area 48.

[0075] For example, when viewed along the longitudinal axis 44, the valve body 42 may have a round shape with a central bore for the control fluid channel 46 to extend therethrough.

[0076] The valve body 42 is movable relative to the rotor body 8. When the pressure of the control fluid contained in the control fluid channel 46 is sufficiently high, the pressure acting on the actuation pressure receiving area 48 generates a force that moves the valve body 42 from its first radial position to its second radial position.

[0077] Control fluid may be delivered from a control fluid source to the control fluid channel 46 from a radially inner portion of the rotor 4 .

[0078] The control fluid channel 46 is kept short by penetrating the valve body 42 to the actuation pressure receiving area 48. The short length results in a small volume and therefore a fast response of the valve body 42 when control fluid is supplied to the pilot valve 40.

[0079] 2a and 2b, the configuration with portion 46' of control liquid channel 46 extending through valve body 42 means that fabrication of control liquid channel 46 in rotor body 8 can be accomplished with a single drilling operation, or with a limited number of drilling operations, thereby facilitating fabrication of control liquid channel 46.

[0080] More specifically, the control liquid channel 46 can have a radial direction through the rotor body 8, or it can be arranged at a slight angle, such as 1 to 30 degrees, to the radial direction. This means that the control liquid channel 46 upstream of the pilot valve 40 can connect to the pilot valve 40 from a radial position inside the pilot valve 40. Furthermore, part of the control liquid channel 46 can be fabricated by a drilling operation through part of the rotor body 8 from the radially outside of the rotor body 8.

[0081] According to embodiments, such as the illustrated embodiment, the control fluid channel 46 may extend radially inward through the rotor body 8 from a portion 46' of the control fluid channel 46 that extends through the valve body 42. In this manner, the control fluid channel 46 may connect directly with the longitudinal axis 44 of the valve body 42 or at a slight angle, such as an angle in the range of 1 to 30 degrees relative to the longitudinal axis 44. Thus, the ease of fabrication discussed above may be achieved, allowing for a short, low-volume control fluid channel 46.

[0082] In the illustrated embodiment, the control fluid channel 46 extends partially through the valve body 42 concentrically with the longitudinal axis 44 of the valve body 42. That is, the portion 46' of the control fluid channel 46 that extends through the valve body 42 extends concentrically with the longitudinal axis 44. Thus, the control fluid channel 46 upstream of the valve body 42 is readily positioned to communicate directly with the portion 46' of the control fluid channel 46 that extends through the valve body 42.

[0083] According to embodiments, such as the illustrated embodiment, the guide member 50 guides movement of the valve body 42 between a first radial position and a second radial position.

[0084] In these embodiments, the guide member 50 may comprise a pin that is fixed relative to the rotor body 8 and that is disposed in a hole in the valve body 42 .

[0085] In addition, the valve body 42 may be guided by a hole in the rotor body 8 or by a hole in a sleeve forming part of the pilot valve 40, for example.

[0086] According to embodiments, such as the illustrated embodiment, the control fluid channel 46 extends partially through the guide member 50. In this manner, at least a portion 46' of the control fluid channel 46 extending through the valve body 42 may be conveniently provided in the guide member 50.

[0087] According to embodiments, such as the illustrated embodiment, the actuating fluid outlet channel 34 extends partially through the guide member 50. In this manner, the valve body 42 may be supported in part by the guide member 50, and the valve body 42 is configured to control the flow of actuating fluid through the actuating fluid outlet channel 34.

[0088] According to an embodiment, such as the illustrated embodiment, the guide member 50 is fixed relative to the rotor body 8 and comprises a central pin 52 on which the valve body 42 is slidably disposed.

[0089] The central pin 52 may, as in the illustrated embodiment, be a separate pin attached to the rotor body 8. Alternatively, at least a portion of the central pin 52 may form an integral part of the rotor body 8.

[0090] The guide member 50 is provided with a through opening 54 that fluidly connects the control liquid channel 46 to the exterior space 36. The through opening 54 has a smaller cross-sectional area within the guide member 50 than the control liquid channel 46.

[0091] The control fluid channel 46 is therefore discharged through the through opening 54 when the pilot valve 40 closes, i.e., when the valve body 42 moves from the second radial position to the first radial position. More specifically, when the supply of control fluid is stopped, the control fluid in the control fluid channel 46 and in the actuation pressure receiving region 48 flows out of the pilot valve 40 through the through opening 54 and into the exterior space 36.

[0092] When control liquid is supplied to the control liquid channel 46 and the actuation pressure receiving area 48, while the pilot valve 40 is open, the small cross-sectional area of ​​the through-opening 54 forms a restriction that causes the control liquid to accumulate in the control liquid channel 46 and the actuation pressure receiving area 48. Thus, the response of the pilot valve 40 can be controlled by the dimensions of the control liquid channel 46 and the through-opening 54, as well as the flow rate at which the control liquid is supplied to the control liquid channel 46.

[0093] According to an embodiment, the valve body 42 can be biased toward the first radial position to close the actuation fluid exhaust channel 34. In this way, when the supply of control fluid to the control fluid channel 46 is stopped and the control fluid is exhausted, the valve body 42 can be reliably returned to its first radial position. Such a bias can also ensure that the valve body 42 is in its first position when the rotor 4 is not rotating.

[0094] In the illustrated embodiment, a biasing member 56, such as a compression spring, biases the valve body 42 toward the first radial position.

[0095] During use of the centrifuge 2, when the valve body 42 is moved from its first radial position to its second radial position, the pressure of the control fluid supplied to the actuation pressure receiving area 48 must overcome not only the centrifugal force of the rotor rotation acting on the valve body 42, but also the biasing force of the biasing member 56.

[0096] During use of the centrifuge 2, as previously described, rotation of the rotor 4 impinges on the valve body 42 with centrifugal force, which urges the valve body 42 toward its first radial position. Thus, according to some embodiments, a separate biasing member may not be necessary.

[0097] Figures 3a and 3b show schematic cross sections of a pilot valve 40 according to an embodiment. The pilot valve 40 is the centrifugal pilot valve discussed above with reference to Figures 1 to 2b. Therefore, in the following, reference is also made to Figures 1 to 2b.

[0098] Again, a pilot valve 40 is disposed on the rotor body 8 for opening and closing the actuation fluid exhaust channel 34. The pilot valve 40 includes a valve body 42. The valve body 42 is movable parallel to its longitudinal axis 44 from a first radial position to a second radial position. A control fluid channel 46 extends to an actuation pressure receiving region 48 of the valve body 42. A portion 46' of the control fluid channel 46 extends through the valve body 42 to the actuation pressure receiving region 48.

[0099] A first radial position of the valve body 42 is shown in Figure 3a and a second radial position of the valve body 42 is shown in Figure 3b.

[0100] 3a and 3b, it can be clearly seen how the control fluid channel 46 extends partially through the guide member 50. That is, a portion 46' of the control fluid channel 46 that extends through the valve body 42 extends through the guide member 50 to the actuation pressure-receiving region 48.

[0101] 3a and 3b, it can further be clearly seen how the working liquid discharge channel 34 extends partially through the guide member 50. From the interior of the rotor body 8, the working liquid discharge channel 34 is led into the guide member 50, where it is directed radially outward. The guide member 50 is provided with one or more outlets 57 for the working liquid. The outlets 57 for the working liquid are led to the exterior space 36, as indicated by dashed arrows in FIG. 3b.

[0102] With the valve body 42 in its first radial position, a portion 58 thereof abuts a sealing surface 60 disposed on the rotor 4. The portion 58 of the valve body 42 and the sealing surface 60 form a sealing interface 62 for the working fluid discharge channel 34. For example, an axial end face 64 of the portion 58 of the valve body 42 may be configured to abut against the sealing surface 60.

[0103] The sealing interface 62 sealingly closes the working fluid exhaust channel 34 when the valve body 42 is in the first radial position, see FIG. 3a.

[0104] The working fluid outlet channel 34 leads to the sealing interface 62 and allows the working fluid to pass through the sealing interface 62 to the outlet 57 when the pilot valve 40 is open.

[0105] According to some embodiments, a ring-shaped recess 66 is provided in the rotor 4 along the longitudinal axis 44 of the valve body 42 and is arranged perpendicular to the longitudinal axis 44. A resilient ring-shaped element 68 is arranged in the ring-shaped recess 66. The resilient ring-shaped element 68 comprises a sealing surface 60. Thus, the sealing surface 60 can be provided on the rotor 4.

[0106] The ring-shaped recess 66 being arranged perpendicular to the longitudinal axis 44 means that the ring-shaped recess 66 extends circularly around the extension of the longitudinal axis 44 .

[0107] The ring-shaped recess 66 may be provided in the rotor body 8. Alternatively, the ring-shaped recess 66 may be provided in a separate element that is fixedly arranged in the rotor body 8.

[0108] The resilient ring-shaped element 68 may be made from a natural or synthetic rubber material.

[0109] According to some embodiments, such as the illustrated embodiment, the sealing interface 62 extends tangentially to the rotor 4 .

[0110] According to an embodiment, a control chamber 70 of the pilot valve 40 is configured to receive a control fluid, and the control chamber 70 is defined in part by the actuation pressure-receiving region 48 of the valve body 42. The control fluid channel 46 leads to the control chamber 70.

[0111] The control chamber 70 forms that portion of the pilot valve 40 that receives control fluid when the valve body 42 is moved from a first radial position to a second radial position.

[0112] A portion 46 ′ of the control fluid channel 46 that extends through the valve body 42 is fluidly connected to a control chamber 70 .

[0113] In the illustrated embodiment, the control chamber 70 is further defined by a sleeve or plug 72 that extends around the rotor body 8 , the guide member 50 , and a portion of the valve body 42 .

[0114] According to some embodiments, the control chamber 70 and the actuation pressure receiving area 48 are configured such that, when control fluid is supplied to the control chamber 70 during operation of the centrifuge, an increase in pressure in the control chamber 70 acting on the actuation pressure receiving area 48 causes the valve body 42 to move from a first radial position to a second radial position, opening the actuation fluid discharge channel 34.

[0115] Thus, the volume of the control chamber 70 changes from a small volume when the valve body 42 is in its first position to a larger volume as the valve body 42 is in its second position. As control fluid enters the control chamber 70 and increases its pressure, the valve body 42 is displaced by a force created by the pressure acting on the actuation pressure-receiving area 48.

[0116] For example, as shown in FIG. 3 a, looking radially inward from pressure receiving region 48 along longitudinal axis 44, a space 71 is provided in pilot valve 40 or rotor body 8. When valve body 42 moves from its first radial position to its second position, at least a portion of valve body 42 is displaced into space 71.

[0117] FIG. 4 shows a schematic cross section of a portion of a pilot valve 40 of a centrifuge according to an embodiment.

[0118] The centrifuge is the centrifuge 2 discussed herein. The pilot valve 40 is configured to operate in a similar manner to that discussed herein with reference to Figures 2a to 3b.

[0119] In these embodiments, the guide member 50 is fixed relative to the valve body 42 and slidably disposed relative to the rotor body 8 .

[0120] Thus, instead of the valve body sliding on the guide member, as in the previously discussed embodiment, the valve body 42 and guide member 50 slide together relative to the rotor body 8 .

[0121] Additionally, a portion 46' of the control fluid channel 46 extends through the valve body 42 from upstream of the pilot valve 40, and the control fluid channel 46 is configured to be directly connected to the portion 46' of the control fluid channel 46 that extends through the valve body 42. Again, the portion 46' of the control fluid channel 46 that extends through the valve body 42 leads to the control chamber 70.

[0122] 4, the valve body 42 is shown in a second radial position. Control fluid is received in the control chamber 70 and acts on the actuation pressure receiving area 48. The actuation fluid exhaust channel 34 is opened, allowing the actuation fluid to exhaust through the actuation fluid outlet 57.

[0123] An exhaust channel 74 from the control chamber 70 is provided through the rotor body 8 .

[0124] It should be understood that the foregoing illustrates various example embodiments, and that the present invention is defined solely by the appended claims. Those skilled in the art will appreciate that the exemplary embodiments may be modified and that various features of the exemplary embodiments may be combined to create embodiments other than those described herein without departing from the scope of the present invention as defined by the appended claims. [Explanation of symbols]

[0125] 2. Centrifuge 4 rotors 6 Rotation Axis 8 Rotor body 10 Outlet opening 12 Separation space 14 Surrounding Space 16 Pilot valve 18 stacks 20 spindles 22 Stationary Housing 24 Electric Motor 26 Entrance 28 Exit 30 slides 32 Operating chamber 34 Operating fluid discharge channel 36 Exterior Space 40 Pilot valve 42 Valve body 44 Longitudinal axis 46 control fluid channels 46' Part of the control fluid channel 48 Operating pressure receiving area 50 Guide member 52 Center pin 54 Through opening 56 biasing member 57 Exit 58 Part of the valve body 60 Sealing surface 62 Sealing interface 64 Shaft end face 66 Ring-shaped recess 68 Elastic Ring-Shaped Elements 70 Control Chamber 71 Space 72 plug 74 Discharge Channel

Claims

1. A centrifuge (2) comprising a rotor (4) configured to rotate about a rotation axis (6) having an axial extension, the rotor (4) comprising a rotor body (8) provided with an outlet opening (10) arranged around the periphery of the rotor body (8), and an axially movable slide (30) arranged within the rotor body (8) for closing the outlet opening (10) in a first axial position and for opening the outlet opening (10) in a second axial position, A separation space (12) is provided in the rotor (4), In the second axial position of the axially movable slide (30), the outlet opening (10) fluidly connects the separation space (12) with an ambient space outside the rotor (4), an operating chamber (32) is provided between the axially movable slide (30) and the rotor body (8) for receiving operating fluid for displacing the axially movable slide (30) from its second axial position to its first axial position; an operating fluid discharge channel (34) extends within the rotor body (8) from the operating chamber (32) to an exterior space (36) of the rotor (4); a pilot valve (40) is disposed within the rotor body (8) for opening and closing the operating fluid discharge channel (34); and a control fluid channel (46) extends at least partially through the rotor body (8) to the pilot valve (40) for supplying control fluid to the pilot valve (40); The pilot valve (40) comprises a valve body (42) having a longitudinal axis (44), the valve body (42) being movable parallel to the longitudinal axis (44) from a first radial position to a second radial position under the influence of the control fluid; The control fluid channel (46) extends to an actuation pressure receiving region (48) of the valve body (42); A centrifuge (2), wherein a portion (46') of the control fluid channel (46) extends through the valve body (42) to the actuation pressure receiving area (48).

2. 2. The centrifuge of claim 1, wherein the control liquid channel extends radially inward through the rotor body from the portion of the control liquid channel that extends through the valve body.

3. 3. The centrifuge (2) of claim 1 or 2, wherein the control fluid channel (46) extends partially through the valve body (42) concentrically with the longitudinal axis (44) of the valve body (42).

4. 4. The centrifuge (2) according to claim 1, wherein a guide member (50) guides movement of the valve body (42) between the first radial position and the second radial position.

5. 5. The centrifuge (2) of claim 4, wherein the control liquid channel (46) extends partially through the guide member (50).

6. 6. The centrifuge (2) according to claim 4 or 5, wherein the working fluid discharge channel (34) extends partially through the guide member (50).

7. 7. The centrifuge (2) according to claim 4, wherein the guide member (50) is fixed relative to the rotor body (8) and comprises a central pin (52) on which the valve body (42) is slidably disposed.

8. 7. The centrifuge (2) according to any one of claims 4 to 6, wherein the guide member (50) is fixed relative to the valve body (42) and is arranged slidably relative to the rotor body (8).

9. 9. The centrifuge (2) according to claim 4, wherein the guide member (50) is provided with a through opening (54) that fluidly connects the control liquid channel (46) with the external space (36), the through opening (54) having a smaller cross-sectional area than the control liquid channel (46) in the guide member (50).

10. 10. The centrifuge (2) of claim 1, wherein the valve body (42) is biased toward the first radial position to close the working fluid discharge channel (34).

11. 11. The centrifuge (2) according to claim 1, wherein a portion (58) of the valve body (42) at the first radial position abuts against a sealing surface (60) arranged on the rotor (4), and the portion (58) of the valve body (42) and the sealing surface (60) form a sealing interface (62) of the working fluid discharge channel (34).

12. 12. The centrifuge (2) of claim 11, wherein a ring-shaped recess (66) is provided in the rotor (4) along the longitudinal axis (44) of the valve body (42) and arranged perpendicular to the longitudinal axis (44), and a resilient ring-shaped element (68) is arranged in the ring-shaped recess (66), the resilient ring-shaped element (68) comprising the sealing surface (60).

13. 13. The centrifuge (2) according to claim 11 or 12, wherein the sealing interface (62) extends in a tangential direction of the rotor (4).

14. 14. The centrifuge (2) of claim 1, wherein a control chamber (70) of the pilot valve (40) is configured to receive the control fluid, the control chamber (70) being partially defined by the actuation pressure receiving region (48) of the valve body (42), and the control fluid channel (46) leading to the control chamber (70).

15. 14. The centrifuge of claim 13, wherein the control chamber and the working pressure receiving area are configured such that, when control fluid is supplied to the control chamber during operation of the centrifuge, an increase in pressure in the control chamber acting on the working pressure receiving area causes the valve body to move from the first radial position to the second radial position to open the working fluid discharge channel.

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