Mechanical Seal Device

Abstract

The present invention relates to a mechanical seal device (16) for a centrifuge (1), the mechanical seal device (16) comprising a first seal ring (18) having a first seal face (20) and a second seal ring (22) having a second seal face (24), the first seal face and the second seal face (20, 24) being configured to face each other to form a seal (50), at least one channel (26) for a cooling fluid being disposed in the first seal ring (18), the at least one channel (26) having an inlet (28) and an outlet (30). The outlet (30) of the at least one channel (26) is disposed in the first seal face (20) of the first seal ring (18). The present invention also relates to a centrifuge (1) comprising the mechanical seal device (16).

Description

[Technical field]

[0001] The present invention relates to a mechanical seal device for a centrifugal separator according to the attached claims.The present invention also relates to a centrifugal separator equipped with a mechanical seal device according to the attached claims. [Background technology]

[0002] The centrifuge is configured to separate liquids, gases, and solid particles from each other. In addition, liquids of different densities mixed together may also be separated from each other in the centrifuge. Gases of different densities mixed together may also be separated from each other in the centrifuge. The centrifuge must be sealed to prevent liquids, gases, or solid particles from leaking out of the centrifuge. Because some parts of the centrifuge rotate, leakage may occur between the rotating and stationary parts. Therefore, a mechanical seal may be disposed between the rotating and stationary parts in the separator. Due to the relative rotational motion between the rotating and stationary parts, heat may be generated between the sealing surfaces of the mechanical seal disposed between the rotating and stationary parts. In some centrifuge applications, the mechanical seal may be an airtight seal.

[0003] US Patent No. 5,399,633 discloses a seal assembly for a centrifuge. The seal assembly comprises two sealing rings arranged such that a double contact seal is formed upon engagement of the two sealing rings. A cooling fluid may be supplied to a chamber in one or both sealing rings. The chamber may be used to detect leaks in the seal assembly. Additionally, a fluid under pressure may be supplied to the chamber to prevent leaks in the seal assembly.

[0004] Patent document 2 discloses a mechanical seal for a centrifuge casing: two sealing rings, one rotatable and one non-rotatable, abut against each other axially to seal the interior of the casing from a connection with the space surrounding the radial bearing through an opening in the bottom of the casing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2020 / 016610 [Patent Document 2] US Patent No. S4654023 Summary of the Invention [Problem to be solved by the invention]

[0006] Heat generated in the mechanical seal due to relative motion between the sealing faces can shorten the life of the mechanical seal. In addition, heat generated in the mechanical seal can lead to seal failure and leakage. Furthermore, large temperature differences in different areas of the mechanical seal can also lead to seal failure and leakage, shortening the life. Therefore, there is a need to develop a mechanical seal device for a centrifuge that has a longer life and provides a tight seal without seal failure and leakage. Furthermore, there is a need to develop a mechanical seal device for a centrifuge that has a low temperature difference in the seal. Additionally, there is a need to develop a centrifuge with a mechanical seal device that has a longer life and provides a tight seal without seal failure and leakage.

[0007] It is therefore an object of the present invention to develop a mechanical seal arrangement for a centrifuge that has a long life and provides a tight seal without seal failure and leakage. It is also an object to develop a mechanical seal arrangement for a centrifuge that provides an airtight seal. It is also an object to develop a mechanical seal for a centrifuge that has a low temperature differential within the seal. It is also an object to develop a centrifuge with a mechanical seal arrangement that has a long life and provides a tight seal without seal failure and leakage. [Means for solving the problem]

[0008] This is achieved by a mechanical seal device for a centrifuge according to the attached claims. This is also achieved by a centrifuge comprising a mechanical seal device according to the attached claims.

[0009] According to an aspect of the present invention, a mechanical seal arrangement for a centrifuge is provided, the mechanical seal arrangement comprising a first seal ring with a first seal face and a second seal ring with a second seal face, the first seal face and the second seal ring with a second seal face configured to face each other to form a sealing ring seal, the first seal ring having a first central axis and the second seal ring having a second central axis, the first central axis of the first seal ring configured to coincide with the second central axis of the second seal ring, at least one channel for a cooling fluid disposed within the first seal ring, the at least one channel having an inlet and an outlet, the outlet of the at least one channel disposed on the first seal face of the first seal ring, the outlet of the at least one channel disposed at a radial distance from the first central axis greater than an outer radius of the formed seal.

[0010] The seal assembly is thus a mechanical seal capable of forming an airtight seal. The seal assembly is for forming a seal between a stationary part and a rotatable part. Such a mechanical seal device has a long life and provides a tight seal with reduced risk of seal failure and leakage. Furthermore, the temperature difference within the mechanical seal device is also low.

[0011] According to the disclosure, the outlet of the at least one channel is located at a radial distance from the first central axis that is greater than the outer radius of the formed seal. Thus, the outlet of the at least one channel is located radially outward of the formed seal of the sealing device. No additional seal is formed in a coaxial plane between two opposing sealing surfaces radially outward of the outlet of the channel in the mechanical seal device.

[0012] The cooling fluid absorbs heat within the mechanical seal device, thereby reducing the temperature within the mechanical seal device. Furthermore, the outlet of the at least one channel is disposed at, i.e., next to, or beside, the first sealing face of the first sealing ring, so that the cooling fluid passes near the first sealing face and, thus, near the formed seal. Heat generated by the relative motion of the first sealing face and the second sealing face may be absorbed by the cooling fluid as it flows through the at least one channel. The at least one channel is configured to equalize the temperature within the sealing ring. The equalized temperature within the sealing ring may prevent cracking or deformation of the sealing ring, as well as cracking or deformation of the first sealing face and the second sealing face. When the cooling fluid flows out of the at least one channel, the outlet of the at least one channel is disposed at, i.e., next to, or beside, the formed seal of the sealing device between the first sealing face and the second sealing face, so that the cooling fluid flows to the area of ​​the first sealing face and the second sealing face. Heat generated by the relative motion of the first and second sealing surfaces may be absorbed by the cooling fluid when the cooling fluid has a fluid connection with the first and second sealing surfaces, which reduces the temperature within the first and second sealing surfaces.

[0013] According to one aspect of the present invention, a centrifuge is provided, the centrifuge comprising the mechanical seal device disclosed herein.

[0014] Such centrifuges equipped with the mechanical seal device disclosed herein provide a tight seal with long life and reduced risk of seal failure and leakage.

[0015] Additional objects, advantages, and novel features of the present invention will become apparent to those skilled in the art from the following details and through the practice of the invention. Although the invention is described below, it will be apparent that the invention may not be limited to the details specifically described. Those skilled in the art will have the opportunity to utilize the teachings herein and will recognize additional applications, modifications, and incorporation in other fields that are within the scope of the invention.

[0016] For a more complete understanding of the present disclosure, and further objects and advantages thereof, the following detailed description should be read in conjunction with the accompanying drawings, in which like reference numerals refer to similar objects in the various drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of a centrifuge according to an example. [Diagram 2] FIG. 2 is a schematic cross-sectional view of an inlet and outlet device of a centrifuge according to an example. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line II in FIG. 2. [Figure 4] FIG. 3 is a detailed schematic diagram of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] According to the present disclosure, a mechanical seal device for a centrifuge is provided. The mechanical seal device comprises a first seal ring with a first seal surface and a second seal ring with a second seal surface, the first seal surface and the second seal surface are configured to face each other to form a seal of the mechanical seal device. The first seal ring has a first central axis and the second seal ring has a second central axis, the first central axis of the first seal ring is configured to coincide with the second central axis of the second seal ring. This means that the first seal ring and the second seal ring may have a common central axis. At least one channel for a cooling fluid is arranged in the first seal ring, the at least one channel comprising an inlet and an outlet. The outlet of the at least one channel is arranged on the first seal surface of the first seal ring, i.e. next to it or beside it. The outlet of the at least one channel is arranged at a radial distance from the first central axis that is greater than the outer radius of the formed seal.

[0019] The seal formed by the mechanical seal device is thus located radially inside the outlet of the channel. The mechanical seal device does not form any further seal or sealing interface between the opposing faces of the first and second sealing rings, which extend radially in the same axial plane as the first and second faces, i.e. radially outside the channel for the cooling fluid. The seal formed is of the single contact seal type.

[0020] The mechanical seal device may be located between a rotating part and a stationary part in a centrifuge. Alternatively, the mechanical seal device may be located between two rotating parts having different rotational speeds. The mechanical seal device may be configured to prevent fluid or gas from passing through the seal. However, the fluid or gas may form a very thin film between the sealing faces of the seal. This thin film has a lubricating effect on the sealing faces.

[0021] The mechanical seal device may provide an airtight seal, which prevents any fluid or gas from passing through the seal.

[0022] The centrifuge may be configured to separate fluids and gases having different densities. The separator may comprise a rotor which, during operation, forms in itself a separation chamber in which the centrifugation of the fluid or gas takes place. The separation chamber is provided with a stack of frusto-conical separation disks to facilitate effective separation of the fluid or gas. A stack of truncated conical separation disks is an example of a surface-enlarging insert, fitted centrally and coaxially with the rotor. During operation of the separator, the fluid or gas to be separated is conveyed to the separation space. Depending on the density, different phases of the fluid or gas are separated between the separation disks. The heavier components of the fluid or gas move radially outward between the separation disks, whereas the less dense phases move radially inward between the separation disks and are forced to pass through an outlet located at the radially innermost level in the separator. The denser components are instead forced to exit through an outlet at a greater radial distance. Any possible solids or sludge in the fluid accumulate around the periphery of the separation chamber and are intermittently forced out of the separation space by a set of radially opening sludge outlets whereupon the sludge is discharged.

[0023] The first seal ring may have a particular diameter and axial extension that is adapted to the type and size of the centrifuge. The first seal face of the first seal ring has a circular configuration. The first seal face has a smoothness that provides an effective seal for fluids and gases.

[0024] The second seal ring may have a particular diameter and axial extension that is adapted to the type and size of the centrifuge. The second seal face of the second seal ring has a circular configuration. The second seal face has a smoothness that provides an effective seal for fluids and gases.

[0025] The first and second sealing surfaces are configured to face each other, and the contact area between the first and second sealing surfaces constitutes the seal of the mechanical seal device. Alternatively, the interface provided by a thin film of fluid or gas between the first and second sealing surfaces constitutes the seal of the mechanical seal device.

[0026] The first and second sealing surfaces may have the same area or different areas.The first and second sealing surfaces may have the same smoothness or different smoothness.

[0027] An actuator may be arranged to bias the first and second sealing surfaces together. Such an actuator may be a spring, such as a coil spring.

[0028] Due to the relative rotational motion between the first seal face and the second seal face, heat may be generated in the sealing faces and in the first seal ring and the second seal ring. In addition, the fluid and gas to be separated in the centrifuge may have a high temperature, which may increase the temperature in the first seal ring and the second seal ring. At least one channel is disposed in the first seal ring, which is configured to reduce the temperature in the mechanical seal device. In addition, the at least one channel is configured to uniformize the temperature in the first seal ring. The uniformized temperature in the first seal ring can prevent cracks and deformations in the first seal ring and the first seal face. In addition, the at least one channel is configured to uniformize the temperature in the second seal ring. The uniformized temperature in the second seal ring can prevent cracks and deformations in the second seal ring and the second seal face.

[0029] A cooling fluid may be provided from a cooling fluid source, which is connected to the centrifuge and to at least one cooling channel of the mechanical seal device. The cooling fluid may be cooled in the cooling fluid source. The cooling fluid may have a specific initial temperature when it enters the centrifuge, which temperature is adapted to the specific separation process in the centrifuge. The cooling fluid may be a liquid, a gas or a powder. The cooling fluid may have lubricating properties. The cooling fluid absorbs heat in the mechanical seal device, thereby reducing the temperature in the mechanical seal device. A pump may be arranged to generate a flow of the cooling fluid in the at least one channel. Gravity may generate the flow of the cooling fluid in the at least one channel.

[0030] The at least one channel may include an inlet and an outlet disposed within the first seal ring, and a cooling fluid may be configured to enter the at least one channel through the inlet and exit the at least one channel through the outlet, such that the at least one channel may form a cooling channel.

[0031] The outlet of the at least one channel is located at, i.e. beside, the first sealing face of the first sealing ring, so that the cooling fluid passes close to the first sealing face. Heat generated by the relative motion of the first sealing face and the second sealing face may be absorbed by the cooling fluid as it flows in the at least one channel. When the cooling fluid flows out of the at least one channel, it flows into the area of ​​the first sealing face and the second sealing face. Heat generated by the relative motion of the first sealing face and the second sealing face may be absorbed by the cooling fluid if the cooling fluid has a fluid connection with the first sealing face and the second sealing face. This reduces the temperature in the first sealing face and the second sealing face.

[0032] Additionally, the outlet of the at least one channel is located a distance from the first central axis greater than the outer radius of the formed seal, such that the outlet of the at least one channel is located radially outward of the outer radius of the first seal face of the first seal ring. This configuration also reduces temperatures within the seal ring, as well as the first seal face and the second seal face.

[0033] According to one embodiment, an outlet of the at least one channel is disposed in fluid communication with a first sealing surface of the first sealing ring and a second sealing surface of the second sealing ring.

[0034] According to one embodiment, the outer radius of the second sealing surface of the second sealing ring is larger than the outer radius of the first sealing surface of the first sealing ring, in which case the outlet of the at least one channel is directed towards the second sealing surface of the second sealing ring. Thus, the outlet of the at least one channel is at least partially arranged and positioned radially inside the outer radius of the second sealing surface of the second sealing ring. This results in the cooling fluid flowing through that portion of the second sealing surface that is positioned radially outside the outer radius of the first sealing surface of the first sealing ring. The heat generated in the second sealing ring may then be effectively absorbed by the cooling fluid when the cooling fluid has a direct fluid connection with the second sealing surface. This results in a lower temperature in the second sealing surface. Furthermore, when the cooling fluid flows through that portion of the second sealing surface that is positioned radially outside the outer radius of the first sealing surface of the first sealing ring, the cooling fluid may easily penetrate between the sealing surfaces and form an extremely thin film between the sealing surfaces. This thin film has a lubricating effect on the sealing surfaces.

[0035] According to one embodiment, a restriction is disposed within or at least one of the channels to restrict the flow of cooling fluid.

[0036] The restriction reduces the flow rate of the cooling fluid in the at least one channel. In addition, the volumetric flow rate of the cooling fluid in the at least one channel is also reduced by the restriction. The restriction may be a portion of the at least one channel having a reduced diameter. The entire length of the at least one channel may be provided with a reduced diameter to achieve the reduced flow rate and volumetric flow rate.

[0037] According to one embodiment, the restriction portion is configured to at least partially cover an entrance opening of at least one channel.

[0038] The restriction portion may be a member disposed to at least partially cover the inlet opening and thereby restrict the cooling fluid from entering the inlet opening. The restriction portion may be a member disposed within the inlet opening and within the at least one channel to partially cover the inlet opening. The restriction portion may be a member disposed outside the inlet opening and thereby within the outside of the at least one channel to partially cover the inlet opening. The restriction portion reduces the flow rate and volumetric flow rate of the cooling fluid in the at least one channel.

[0039] According to one aspect, the restricting portion is a washer element configured to rest on the first seal ring and configured to at least partially cover an entrance to the at least one channel.

[0040] The inner diameter of the washer element may be larger than the inner diameter of the first sealing ring. The entrance of the at least one channel in the first sealing ring may be partially covered by the inner circumference of the washer element. The outer diameter of the washer element may be smaller than the outer diameter of the first sealing ring. The entrance of the at least one channel in the first sealing ring may be partially covered by the outer circumference of the washer element. The inner or outer circumference of the washer element may be provided with a bevel, which is adapted so that the washer element partially covers the entrance of the at least one channel. Alternatively, the washer element may comprise a through hole having a diameter smaller than the entrance of the at least one channel.

[0041] According to one embodiment, at least two channels are evenly distributed around the first seal ring.

[0042] By distributing at least two channels evenly around the first seal ring, the flow of cooling fluid may be evenly distributed within the channels, which provides a uniform temperature within the first seal ring, thereby avoiding any temperature gradients within the first seal ring.

[0043] According to one embodiment, the number of channels can be between 2 and 10, for example between 4 and 8, for example 6, spaced apart and evenly distributed around the first sealing ring, thereby allowing for sufficient cooling around the periphery of the sealing ring, while the mechanical properties are not negatively affected. However, larger centrifuges with mechanical seal devices having larger diameters may have a larger number of channels evenly distributed around the first sealing ring.

[0044] By distributing the channels evenly around the first seal ring, the flow of cooling fluid through the channels can be evenly distributed, which results in a uniform temperature within the first seal ring, thereby avoiding any temperature gradients within the first seal ring.

[0045] According to one embodiment, the material in the second seal ring is harder than the material in the first seal ring.

[0046] The first seal surface of the first seal ring may slide over the second seal surface of the second seal ring during relative motion between the first seal ring and the second seal ring, which may result in surface wear. Because the material in the second seal ring is harder than the material in the first seal ring, wear occurs substantially within the first seal ring. Thus, only the first seal ring needs to be replaced during maintenance of the mechanical seal device.

[0047] According to one embodiment, the material in the second seal ring includes silicon carbide and the material in the first seal ring is graphite.

[0048] The silicon carbide in the second seal ring is harder than the graphite in the first seal ring. Thus, wear occurs substantially in the first seal ring. Thus, only the first seal ring needs to be replaced during maintenance of the mechanical seal device. The graphite first seal ring can be manufactured at low cost. Thus, replacement of the first seal ring can be performed at low cost.

[0049] According to one embodiment, the material in the second seal ring has a thermal conductivity greater than the thermal conductivity of the material in the first seal ring.

[0050] The greater thermal conductivity in the second seal ring can absorb heat from heat generation during the relative motion of the seal faces and transfer the heat away from the second seal face. At least one channel is disposed in the first seal ring so that the generated heat is transferred away from the first seal ring utilizing a cooling fluid.

[0051] According to one aspect, at least one channel in the first seal ring has an extension parallel to the first central axis.

[0052] By positioning the first seal ring in place such that the first central axis has a vertical extension within the centrifuge, at least one channel in the first seal ring also has a vertical extension. Cooling fluid can flow within the at least one channel by gravity when the channel has a vertical extension.

[0053] According to one embodiment, the first seal surface of the first seal ring has a first normal and the second seal surface of the second seal ring has a second normal, where the directions of the first normal and the second normal are parallel to the direction of the first central axis of the first seal ring and parallel to the direction of the second central axis of the second seal ring.

[0054] The first and second sealing faces are configured to face each other to form a seal, such that the first and second perpendicular lines of the sealing faces are oriented toward each other. This arrangement provides a tight seal without seal failure and leakage. The contact area of ​​the first and second sealing faces is defined by the inner and outer diameters of the first and second sealing rings.

[0055] According to one aspect, the first seal ring is configured to be stationarily disposed and the second seal ring is configured to be rotatably disposed.

[0056] The stationary first seal ring may simplify the arrangement for directing the cooling fluid through the at least one channel.

[0057] According to the present disclosure, a centrifuge is provided, the centrifuge including the mechanical seal device disclosed herein.

[0058] Such centrifuges equipped with the mechanical seal devices disclosed herein provide tighter seals with longer life and reduced risk of seal failure and leakage. In addition, maintenance of the mechanical seal devices in the centrifuges is simplified and low-cost.

[0059] A mechanical seal device for a centrifuge and a centrifuge equipped with the mechanical seal device are described with reference to the accompanying drawings.

[0060] FIG. 1 shows a schematic representation of a centrifuge 1 according to an example. The separator 1 comprises a rotor 2 which forms in itself a separation chamber 4 in which the centrifugation of the fluid or gas takes place during operation. The separation chamber 4 is provided with a stack of frusto-conical separation discs 6 to facilitate effective separation of the fluid or gas. During operation of the separator, the fluid or gas to be separated is conveyed into the separation chamber 4 through an inlet and outlet device 8 of the centrifuge 1. Depending on the density, different phases of the fluid or gas are separated between the separation discs. The heavier components of the fluid or gas move radially outward between the separation discs 6, whereas the less dense phases move radially inward between the separation discs 6 and are forced through a first outlet 10 arranged at the radially innermost level in the separator 1 and are further forced towards the inlet and outlet device 8. The higher density components are forced through a second outlet 12 at a greater radial distance, which is intermittently discharged from the separation chamber 4. The inlet and outlet arrangement 8 comprises a first inlet 14 for the fluid or gas to be separated.

[0061] FIG. 2 shows a schematic cross-sectional view of an inlet and outlet device 8 of a centrifuge 1 according to an example. The inlet and outlet device 8 comprises a first inlet 14 and a first outlet 10. A mechanical seal device 16 is arranged in the inlet and outlet device 8. The mechanical seal device 16 comprises a first seal ring 18 having a first seal face 20 and a second seal ring 22 having a second seal face 24. The first seal face 20 and the second seal face 24 are configured to face each other to form a seal. Channels 26 for a cooling fluid are arranged in the first seal ring 18. Each channel 26 comprises an inlet 28 and an outlet 30. The outlet 30 of each channel 26 is arranged at the first seal face 20 of the first seal ring 18, i.e. beside it. Each channel 26 is arranged in fluid connection with the first seal face 20 of the first seal ring 18 and the second seal face 24 of the second seal ring 22. The cooling fluid is supplied from a cooling fluid source 32, which is connected to a second inlet 34 of the centrifuge 1. The first sealing ring 18 is configured to be stationarily arranged within the inlet and outlet arrangement 8. The second sealing ring 22 is connected to a rotatable component of the centrifuge 1, such that the second sealing ring 22 is configured to be rotatably arranged.

[0062] The first seal ring 18 has a first central axis 36 and the second seal ring 22 has a second central axis 38. The channel 26 in the first seal ring 18 extends parallel to the first central axis 36. The first central axis 36 of the first seal ring 18 coincides with the second central axis 38 of the second seal ring 22.

[0063] The cooling fluid enters the centrifuge 1 through the second inlet 34. From there it flows into a cavity 39 in which an actuator 41 is located to urge the first sealing surface 20 and the second sealing surface 24 together. In Figure 2 the actuator 41 is a spring.

[0064] Figure 3 shows a schematic cross-sectional view along line II in Figure 2. Six channels 26 are arranged in the first seal ring 18. The channels 26 are evenly distributed around the first seal ring 18, so that the flow of cooling fluid through the channels 26 is evenly distributed. The evenly distributed channels 26 in the first seal ring 18 make the temperature in the first seal ring 18 uniform, thereby avoiding any temperature gradients in the first seal ring 18.

[0065] 4 shows a schematic detailed view of FIG. 2. The detailed view shows the mechanical seal device 16 in more detail. A washer element 40 is configured to rest on the first seal ring 18 and is configured to at least partially cover the inlet 28 of the channel 26. The washer element 40 restricts the flow of cooling fluid in the channel 26. By associating a washer element or other restriction of this type in association with each channel, the flow of cooling fluid through the channels 26 can be evenly distributed.

[0066] The first sealing face 20 of the first seal ring 18 has a first perpendicular line 42 and the second sealing face 24 of the second seal ring 22 has a second perpendicular line 44. The directions of the first perpendicular line 42 and the second perpendicular line 44 are parallel to the directions of the first central axis 36 of the first seal ring 18 and the second central axis 38 of the second seal ring 22. A seal and / or sealing interface 50 of the mechanical seal device 16 is formed between the first seal face 20 and the second seal face 24.

[0067] Arrows 46 in Fig. 4 represent the flow direction and path of the cooling fluid. The cooling fluid enters the centrifuge 1 through the second inlet 34 (see Fig. 2) and further into the cavity 39. From the cavity 39, the cooling fluid flows through a circular passage formed between the washer element 40 and the stationary element 48 of the inlet and outlet device 8 of the centrifuge 1. The cooling fluid then flows into the inlet 28 of the channel 26 and towards the outlet 30.

[0068] The outlet 30 of the channel 26 is located at a radial distance D from the first central axis 36 that is greater than the outer radius R1 of the first sealing face 20 of the first sealing ring 18. The outer radius R1 also forms the outer radius R1 for the formed seal 50, since the seal is formed between the first sealing face 20 and the second sealing face 24. The outlet 30 of the channel 26 is thus located radially outside the outer radius R1 of the first sealing face 20 of the first sealing ring 18. The outlet 30 of the channel 26 is located at the first sealing face 20 of the first sealing ring 18, i.e. to the side thereof. The cooling fluid therefore passes close to the first sealing face 20 and thus close to the seal 50 of the mechanical seal arrangement. As can be seen from the drawing, no further seal between the first sealing face of the first sealing ring and the second sealing face of the second sealing ring is included radially outside the seal 50.

[0069] The outer radius R2 of the second sealing face 24 of the second sealing ring 22 is greater than the outer radius R1 of the first sealing face 20 of the first sealing ring 18, in such a way that the outlet 30 of the at least one channel 26 can be directed towards the second sealing face 24 of the second sealing ring 22. In such a way, the cooling fluid thus flows over a portion of the second sealing face 24, which portion is positioned radially outside the first sealing face 20 of the first sealing ring 18 having the outer radius R1. A small amount of the flow of the cooling fluid may thus penetrate between the sealing faces 20 and 24 and form an extremely thin fluid film between the sealing faces 20 and 24. However, the majority of the cooling fluid after passing through the first sealing ring 18 and the second sealing ring 22 is discharged through an outlet port (not shown) of the centrifuge 1.

[0070] The above description of examples of the present disclosure is provided for the purpose of illustration and description. It is not intended to be exclusive or to limit the disclosure to the examples and variations described. Many modifications and variations will naturally be apparent to those skilled in the art. The examples have been selected and described to best explain the principles of the disclosure and the application of its implementations, and therefore to enable experts to understand the disclosure in terms of the various examples and with various modifications appropriate to the intended use. [Explanation of symbols]

[0071] 1. Centrifuge 2 Rotors 4. Separation Chamber 6 Separation disc 8 Inlet and outlet devices 10 Exit 1 12 Second Exit 14 First Entrance 16 Mechanical seal device 18 First Seal Ring 20 First sealing surface 22 Second seal ring 24 Second sealing surface 26 Channels 28 Entrance 30 exit 32 Cooling Fluid Supply Source 34 Second Entrance 36 First central axis 38 Second Central Axis 39 Cavity 40 Washer element, restriction part 41 Actuator 42 First Perpendicular 44 Second Perpendicular 46 Arrow 48 Static Elements 50 Seals R1 outer radius R2 outer radius D radial distance

Claims

1. A centrifuge (1) having a mechanical seal device (16), the centrifuge (1) comprising: A rotor (2) which forms a separation chamber (4) within itself, said separation chamber comprising a stack of frusto-conical separation discs (6), The mechanical seal device (16) comprises: a first seal ring (18) having a first seal surface (20); a second sealing ring (22) having a second sealing surface (24); the first sealing surface and the second sealing surface (20, 24) are configured to face each other to form a seal (50) of the mechanical seal device; the first seal ring (18) has a first central axis (36) and the second seal ring (22) has a second central axis (38), the first central axis (36) of the first seal ring (18) being configured to coincide with the second central axis (38) of the second seal ring (22); At least one channel (26) for a cooling fluid is disposed in said first seal ring (18), said at least one channel (26) having an inlet (28) and an outlet (30); the outlet (30) of at least one of the channels (26) is disposed to the side of the first sealing face (20) of the first sealing ring (18), and the outlet (30) of at least one of the channels (26) is disposed at a radial distance (D) from the first central axis (36) that is greater than an outer radius (R1) of the formed seal (50); A restriction portion (40) is disposed in association with and outside at least one of said channels (26) for restricting the flow of said cooling fluid.

2. 2. The centrifuge (1) of claim 1, wherein the outlet (30) of at least one of the channels (26) is arranged in fluid communication with the first sealing surface (20) of the first sealing ring (18) and the second sealing surface (24) of the second sealing ring (22).

3. 3. The centrifuge (1) according to claim 1, wherein an outer radius (R2) of the second sealing face (24) of the second sealing ring (22) is greater than the outer radius (R1) of the first sealing face (20) of the first sealing ring (18), and the outlet (30) of at least one of the channels (26) is directed towards the second sealing face (24) of the second sealing ring (22).

4. The centrifuge (1) according to any one of claims 1 to 3, wherein the restriction portion (40) is configured to at least partially cover the inlet (28) of at least one of the channels (26).

5. 5. The centrifuge (1) according to claim 1, wherein the restricting portion (40) is a washer element (40) configured to be mounted on the first sealing ring (18) and configured to at least partially cover the inlet (28) of at least one of the channels (26).

6. 6. The centrifuge (1) according to any one of claims 1 to 5, wherein at least two channels (26) are evenly distributed around the first sealing ring (18).

7. 7. The centrifuge (1) according to any one of claims 1 to 6, wherein the number of said channels (26) is between four and eight, spaced apart, and the channels (26) are evenly distributed around the first sealing ring (18).

8. 8. The centrifuge (1) according to any one of claims 1 to 7, wherein the material in the second sealing ring (22) is harder than the material in the first sealing ring (18).

9. 9. The centrifuge (1) according to any one of the preceding claims, wherein the material of the second seal ring (22) comprises silicon carbide and the material of the first seal ring (18) is graphite.

10. 10. The centrifuge (1) according to any one of claims 1 to 9, wherein the material in the second sealing ring (22) has a thermal conductivity greater than the thermal conductivity of the material in the first sealing ring (18).

11. 11. The centrifuge (1) according to any one of claims 1 to 10, wherein at least one of the channels (26) in the first sealing ring (18) has an extension parallel to the first central axis (36).

12. 12. The centrifuge (1) according to any one of claims 1 to 11, wherein the first sealing surface (20) of the first sealing ring (18) has a first perpendicular line (42) and the second sealing surface (24) of the second sealing ring (22) has a second perpendicular line (44), the directions of the first perpendicular line and the second perpendicular line (42, 44) being parallel to the direction of the first central axis (36) of the first sealing ring (18) and parallel to the direction of the second central axis (38) of the second sealing ring (22).

13. 13. The centrifuge (1) according to any one of claims 1 to 12, wherein the first sealing ring (18) is configured to be stationary and the second sealing ring (22) is configured to be rotatable.

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