WO2000053329A1

WO2000053329A1 - A device for the supply of lubrication oil for a centrifugal separator

Info

Publication number: WO2000053329A1
Application number: PCT/SE2000/000461
Authority: WO
Inventors: Jouko PITKÄMÄKI; Jan Setterberg; Lars-Erik Skytt
Original assignee: Alfa Laval Ab
Priority date: 1999-03-08
Filing date: 2000-03-08
Publication date: 2000-09-14
Also published as: SE9900819D0; SE9900819L; SE521030C2

Abstract

The invention refers to a device for the supply of lubrication oil for centrifugal separator. The device includes a spindle (3), which is arranged to carry a centrifuge rotor of said centrifugal separator and is rotatably journalled in at least one bearing member (5) about a centre axis (Z), and an oil container (8), which is arranged to contain a quantity of oil. The spindle extends from the centrifuge rotor to the oil container in such a manner that at least an end portion of the spindle is located in said quantity of oil. The spindle forms a longitudinal channel (29), which has an orifice in said end portion and which is arranged to transport an oil flow through the channel (29). The channel includes a distribution member (31), which is arranged to divide a first selected amount of said oil flow for further transport to said bearing member (5) and to convey the remaining amount of said oil flow out of the channel (29) for being returned to the oil container (8).

Description

A device for the supply of lubrication oil for a centrifugal separator

The present invention refers to a device for the supply of lubrication oil for a centrifugal separator, which device includes a spindle, which is arranged to carry a centrifuge rotor of said centrifugal separator and is rotatably journalled in at least one bearing member about a centre axis, and an oil container, which is arranged to contain a quantity of oil, wherein the spindle extends from the centrifuge rotor to the oil container in such a manner that at least an end portion of the spindle is located in said quantity of oil, and wherein the spindle forms a longitudinal channel, which has an orifice in said end portion and which is arranged to transport an oil flow through the channel.

It is a problem to obtain a correct lubrication and cooling of the bearings which carry the centrifuge rotor of a centrifugal separator. If the bearing receives too much lubrication oil, the friction increases and if the bearing receives too little lubrication oil, there is a risk that the bearing jams.

DE-1 031 222 discloses a device of the above-mentioned type for the supply of lubrication oil to a bearing member for a spindle of a centrifugal separator. The spindle extends from a centrifuge rotor to an oil container in such a manner that an end portion of the spindle is located in the oil. The spindle forms an inner longitudinal channel, which has an orifice in the end portion and which is arranged to transport an oil flow vertically upwardly through the channel. From the channel extends a substantially radial discharge channel to a chamber which is provided above the bearing members to be lubricated. The oil which is discharged from the discharge channel is conveyed downwardly in an oil mist through the bearing members to be lubricated. One problem of this device is that it does not offer any possibility to determine the amount of oil to be supplied to the bearing members.

DE-C-759 025 discloses another device of the above-mentioned type having an inner longitudinal channel for the transport of oil from an oil container up to two bearing members. The longitudinal channel includes no distribution member but merely radial holes which extend through the channel wall and are arranged to permit discharge of oil from the inner longitudinal channel.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a device for the supply of lubrication oil, by which it is possible to ensure that a bearing always receives a determined, selected amount of lubrication oil independent of the state of operation.

This object is obtained by the device for the supply of lubrication oil initially defined, which is characterised in that the channel includes a distribution member, which is arranged to divide a first selected amount of said oil flow for further transport to said bearing member and to convey the remaining amount of said oil flow out of the channel for being returned to the oil container, and in that means are arranged to create a gas flow, which flows in a direction towards and through said bearing member, and thereby to bring the first amount through said bearing member.

By such a distribution member, the desired amount of oil , which is required for lubricating said bearing member may be divided from the oil flow through the channel and the remaining amount may be returned without passing through the bearing member.

According to an embodiment of the invention, the distribution member includes at least wall portion, which has a surface arranged to convey the first amount in the channel in a direction towards said bearing member, and at least a passage, which is arranged to convey the remaining amount out of the channel. By a suitable choice of dimensions of such a surface, it is possible to divide a determined amount of oil to the bearing member. The distribution member may include a plurality of such wall portions, which each adjoins two passages. Preferably, said wall portion extends obliquely outwardly with respect to the centre axis.

According to a further embodiment of the invention, the channel includes a connection portion, which is provided downstream of said wall portion and which connects said wall portion to at least one discharge channel, which is arranged to feed the first amount out of the channel to said bearing member.

According to a further embodiment of the invention, the centrifuge rotor is journalled in a further bearing member, wherein said gas flow is arranged to bring at least a part of the discharged amount through said bearing member and through the further bearing member. In such a manner, the oil will be transported in the form of an oil mist through the further bearing member. Advantageously, said discharge channel extends outwardly in a direction which has a radial component and a tangential component, wherein said discharge channel, seen radially outwardly, extends forwardly with respect to the rotary direction of the spindle. By such an extension of the discharge channel, it is ensured that the oil is not jetted out of the discharge channel but leaves the same in a controlled manner towards the bearing member. Preferably, said discharge channel connects in the proximity of an active bearing surface of said bearing member.

According to a further embodiment of the invention, the device for the supply of lubrication oil includes a tubular sleeve, which is provided around the distribution member and which forms said connection portion. Such a sleeve may have an end portion, which is provided adjacent to said bearing member, wherein said discharge channel includes at least one groove of the end portion. Furthermore, the sleeve may be threaded on a pin of the spindle, wherein the connection portion is formed by at least one recess, which extends along an inner wall of the sleeve. According to a further embodiment of the invention, a chamber is provided radially outside said wall portion for collecting the remaining amount, wherein at least one discharge passage extends from the chamber outwardly in a direction towards the oil container. Preferably, the chamber extends around the channel and is provided between the sleeve and the distribution member. Such a chamber may have dimensions permitting to receive the whole amount of lubrication oil to be returned to the oil container.

According to a further embodiment of the invention, the distribution member includes a base portion, from which said wall portion extends, wherein the base portion includes a central passage, which forms a part of the channel and which has a reduced diameter in relation to the channel upstream and downstream of the central passage, and wherein the base portion includes at least two arms forming said wall portions. Such a distribution member may be manufactured as a separate, easily replaceable unit, which may be mounted in said channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now to be explained more closely by means of an embodiment, which is described as an example, and with reference to the drawings attached, in which

Fig 1 discloses schematically a partly sectional perspective view of a drive unit for a centrifuge rotor of a centrifugal separator, Fig 2 discloses an axial sectional view through a part of the drive unit in Fig 1 ,

Fig 3 discloses a perspective view of a distribution member of a device for the supply of lubrication oil according to the invention, and Fig 4 discloses a view from above of a sleeve, which is arranged to receive the distribution member in Fig 3. DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

Fig 1 discloses a drive unit 1 for a partly disclosed centrifuge rotor 2. The drive unit 1 and the centrifuge rotor 2 form together substantial components of a centrifugal separator. The drive unit 1 includes a spindle 3, which carries the centrifuge rotor 2 and is rotatable about a rotary axis z, see Fig 2. The spindle 3 is carried by a first, upper bearing member 4 and a second, lower bearing member 5, see Fig 2. Furthermore, the drive unit 1 includes a casing 6, which delimits an inner space 7, in which the spindle 3, the first bearing member 4 and the second bearing member 5 are located. The space 7 forms in an lower part thereof an oil container 8 for receiving a liquid lubrication oil. The drive unit 1 also includes a drive motor (not disclosed), which is connected to a belt pulley 9. The drive motor and the belt pulley 9 are provided outside the casing 6 and connected to a belt pulley 10, which is fixedly provided on the spindle 3, by means of an transferring member, which in the example disclosed includes a drive belt 1 1 , which extends through a passage 12 in the casing 6.

The upper bearing member 4, the so-called neck bearing, is carried by means of a bearing housing 13. The bearing housing 13 is connected to a first shielding member 14, which includes at least a shielding portion, which extends outwardly, preferably substantially radially outwardly, from the upper bearing member 4 in a direction towards an inner wall of the casing 6. The bearing housing 13 and the shielding member 14 are in the example disclosed designed to form a space 15, which is intended to receive damping elements known per se (not disclosed). A second shielding member 16 extends substantially axially downwardly from a radially outer edge of the first shielding member 14 between the spindle 3 and an inner wall of the casing 6 in such a way that an annular passage 17 is formed therebetween. The second shielding member 16 extends in the example disclosed around the spindle 3 and downwardly in such a way that merely a thin gap is formed between a lower edge of the second shielding member 16 and the oil in the oil container 8. Furthermore, the drive unit 1 includes a fan wheel 18, which is fixedly provided on the spindle 3, in the example disclosed, above the upper bearing 4. The fan wheel 18 is arranged to circulate a flow of air and oil mist in the inner space 7 and through the upper bearing member 4 and the lower bearing member 5 for cooling and lubricating thereof. The fan wheel 18 is thereby arranged to force said flow from an outlet of the upper bearing member 4 radially outwardly in a direction towards the inner wall of the casing 6 and axially downwardly through the passage 17 between the inner wall of the casing 6 and the second shielding member 16 back to the oil container 8.

Furthermore, the drive unit 1 includes a separating member 19, which is provided inside the casing 6 and which is arranged to house the part of the drive belt 1 1 extending inside the casing 6 in such a way that the drive belt 1 1 is separated from the inner space 7 of the casing 6. The separating member 19 is connected to the inner wall of the casing 6 at two diametrically opposite sides by means of a respective connection , which extends around the above- mentioned passage 12 and a diametrically opposite passage. Consequently, the separating member 19 forms a channel 21 , which extends substantially diametrically through the inner space 7 with regard to the rotary axis z and which is separated from this space 7. The separating member 19 has an elongated, box-like shape, i.e. it is substantially rectangular seen in a cross-section. The separating member 19 includes an upper opening 22 and a lower opening 23. The spindle 3 extends through the separating member 19 through these openings 22, 23, wherein the upper opening 22 also is arranged to receive a part of the drive pulley 10. As is indicated in Fig 2, a sealing member 20 is provided between the belt pulley 10 and the upper limiting wall of the separating member 19.

A stationary pipe member 24 is fixedly provided in a bottom of the oil container 8. The pipe member 24 extends upwardly from the oil container 8 through the lower opening 23 of the separating member

19. The pipe member 24 is arranged to receive the lower end of the spindle 3. The lower bearing member 5 is connected to the pipe member 24 and the lower end of the spindle 3, and permits the rotation of the spindle 3 in relation to the pipe member 24. Furthermore, the pipe member 24 includes a number of inlet channels 25, which connect the oil container to an inner space of the pipe member 24 and permits a flow of oil from the oil container 8 to the inner space of the pipe member 24. A filter member 26 is provided around the pipe member 24 and covers the openings of the inlet channels 25.

The end portion of the spindle 3, which is located in the inner space of the pipe member 24, includes a sleeve, which includes an inner thread by which the sleeve 27 is threaded onto a threaded spindle pin 28 on the spindle 3. As appears from Fig 2, the lower bearing member 5 is tightened between the belt pulley 10 and the sleeve 27. The sleeve 27 extends below the spindle pin 28 and forms a longitudinal channel 29, which has an orifice 30 at its end, wherein this orifice 30 will be located in the oil. Due to the rotation of the spindle 3 and the sleeve 27, oil will be sucked upwardly through the orifice 30 and up through the channel 29.

In the sleeve 27, a distribution member 31 is provided. The distribution member 31 is disclosed in Fig 3 and includes a base portion 32 and two arms 33 extending from the base portion. A central passage 34 extends through the base portion 32 and permits through-flowing of the oil. As appears from Fig 3, the base portion 32 includes a substantially plane upper surface 35. The arms 33 include a respective concave wall portion 36, which forms a respective flow path for the lubrication oil. Each such concave wall portion 36 extends in the example disclosed upwardly and obliquely outwardly in a first portion and thereafter radially outwardly in a second portion. As appears from Fig 3, the distribution member 31 is a separate unit, which is introduceable into the sleeve 27. The sleeve 27 includes two longitudinal diametrically opposite recesses 37, which are disclosed in Fig 4 and which form a connection portion of the channel 29 between the space below the spindle pin 21 and a respective discharge channel 38. Each discharge channel 38 extends outwardly in a direction which has a radial component and a tangential component. Furthermore, the discharge channels 38 extend forwardly with respect to the rotary direction of the spindle, which is indicated by the arrow a in Fig 4. Each discharge channel 38 is formed by a groove in an end portion 39 of the sleeve 27. The end portion 39 includes a number of passages 40, which in the example disclosed extend substantially vertically. The discharge channels 38 extend from a respective recess 37 to one of said passages 40.

Furthermore, the sleeve 27 includes an annular chamber 41 , which is located radially outside the arms 33. The chamber 41 is delimited radially inwardly merely by the arms 33 so that passages 42 are formed between the arms 33 from the channel 29 to the chamber 41. From the chamber 41 , a number of discharge passages 43 extend obliquely downwardly outwardly. Below the discharge passages 43, a surrounding catch groove (not disclosed) is provided, which leads the return flow from the inner space of the pipe member 24 to the oil container 8 via a channel through the wall of the pipe member 24.

Furthermore, the pipe member 24 includes a number of substantially radial holes 44, which connect the inner space of the pipe member 24 with the inner space 7. The above-mentioned flow will thus flow from the inner space 7 through the holes 44 and upwardly in an annular gap, which is located between the sleeve 27 and an inner wall of the pipe member 24. Thereafter, the flow flows through the passages 40, which are located immediately beneath the lower bearing member 5. The flow thus flows through the lower bearing member 5 and more exactly passes the rolling bodies of the bearing member 5. From the bearing member 5, the flow flows further upwardly and through the connection channels 45, which extend through the belt pulley 10. From the connection channels 45, the flow will then flow upwardly and through the upper bearing member 4, see Fig 1 . During operation of the centrifugal separator, the oil, which is present in the inner space of the pipe member 24, will thus be brought to rotation by the contact with the end portion of the spindle 3. It is to be noted that a radially outer volume of oil in this inner space will not rotate thanks to a number of radial wings 46. Due to the rotation of the spindle 3, the oil present at the orifice 30 will be sucked upwardly through the orifice 30 into the channel 29 and through the central passage 34 of the distribution member 31 . Oil will thus be collected on the plane surface 35 of the distribution member 31 . Due to the centrifugal force, the oil will be fed outwardly from the surface 35 and a larger quantity of the oil will thereby be transported through the passages 42 between the arms 33 to the chamber 41 from which it is conveyed downwardly through the discharge passages 43 and back to the oil container 8, and more exactly to the quantity of oil, which is present in the inner space of the pipe member 24. A determined amount of oil, however, will be conveyed upwardly on the concave wall portions 36 and further upwardly along the recesses 37. From the recesses 37, the oil is conveyed outwardly in the discharge channels 38 to a respective passage 40. Thanks to the extension of the discharge channels 38 forwardly with respect to the rotary direction a, the oil will exit the discharge channels 38 with a reduced angle velocity. The oil exiting the discharge channels 38 will thereby be brought by the flow through the passages 40 and into the lower bearing member 5. The oil is then conveyed with the flow further through this bearing member 5 and the connection channels 45 up to the upper bearing member 4. In such a way, a properly balanced lubrication and cooling is obtained for the lower bearing member 5 as well as the upper bearing member 4.

The invention is not limited to the embodiment disclosed, but may be varied and modified within the scope of the following claims.

For instance, the distribution member 31 may include another number of arms 33 than those two disclosed. Within the scope of the invention, it is possible to provide merely one such arm 33 or a plurality of arms 33, each having a concave wall portion 36. Furthermore, it is to be noted that the recesses 37, the number of which preferably corresponds to the number of arms 33, may be provided on the spindle pin 28 and not on the inner wall of the sleeve 27. In the same way, the discharge channels 38 may also be provided in the bearing member 5 instead of on the end portion 39 of the sleeve 27.

Claims

1 . A device for the supply of lubrication oil for a centrifugal separator, which device includes a spindle (3), which is arranged to carry a centrifuge rotor (2) of said centrifugal separator and is rotatably journalled in at least one bearing member (4,5) about a centre axis (z), and an oil container (8), which is arranged to contain a quantity of oil, wherein the spindle (3) extends from the centrifuge rotor (2) to the oil container (8) in such a manner that at least an end portion of the spindle (3) is located in said quantity of oil, and wherein the spindle forms a longitudinal channel (29), which has an orifice (30) in said end portion and which is arranged to transport an oil flow through the channel (29), characterised in that the channel includes a distribution member (31 ), which is arranged to divide a first selected amount of said oil flow for further transport to said bearing member (4, 5) and to convey the remaining amount of said oil flow out of the channel (29) for being returned to the oil container (8), and in that means ( 18) are arranged to create a gas flow, which flows in a direction towards and through said bearing member (4, 5), and thereby to bring the first amount through said bearing member (4, 5).

2. A device for the supply of lubrication oil according to claim 1 , characterised in that the distribution member (31 ) includes at least one wall portion (36), which has a surface arranged to convey the first amount in the channel (29) in a direction towards said bearing member (4, 5), and at least one passage (42), which is arranged to convey the remaining amount out of the channel (29).

3. A device for the supply of lubrication oil according to claim 2, characterised in that the distribution member (31 ) includes a plurality of such wall portions (36), which each adjoins two passages (42).

4. A device for the supply of lubrication oil according to any one of claims 2 and 3, characterised in that said wall portion (36) extends obliquely outwardly with respect to the centre axis (z).

5. A device for the supply of lubrication oil according to any one of claims 2-4, characterised in that the channel (29) includes a connection portion (37), which is provided downstream of said wall portion (36) and which connects said wall portion to at least one discharge channel (38), which is arranged to feed the first amount out of the channel (29) to said bearing member (4, 5).

6. A device for the supply of lubrication oil according to claim 5, wherein the centrifuge rotor (2) is journalled in a further bearing member (4), characterised in that said gas flow is arranged to bring at least a part of the discharged amount through said bearing member (5) and through the further bearing member (4).

7. A device for the supply of lubrication oil according to any one of claims 5 and 6, characterised in that said discharge channel (38) extends outwardly in a direction which has a radial component and a tangential component, wherein said discharge channel (38) extends forwardly with respect to the rotary direction (a) of the spindle.

8. A device for the supply of lubrication oil according to any one of claims 5-7, characterised in that said discharge channel (38) has an orifice in the proximity of an active bearing surface of said bearing member (5).

9. A device for the supply of lubrication oil according to any one of claims 5-8, characterised by a tubular sleeve (27), which is provided around the distribution member (31 ) and which forms said connection portion (37).

10. A device for the supply of lubrication oil according to claims 5 and 9, characterised in that the sleeve (27) has an end portion (39), which is provided adjacent to said bearing member (5), wherein said discharge channel (38) includes at least one groove of the end portion (39).

1 1. A device for the supply of lubrication oil according to any one of claims 9 and 10, characterised in that the sleeve (27) is threaded to a pin (28) of the spindle (3), wherein the connection portion is formed by at least one recess (37), which extends along an inner wall of the sleeve (27).

12. A device for the supply of lubrication oil according to any one of claims 2-1 1 , characterised in that a chamber (48) is provided radially outside said wall portion (36) for collecting the remaining amount, wherein at least one discharge passage (43) extends from the chamber (41 ) outwardly in a direction towards the oil container (8).

13. A device for the supply of lubrication oil according to claims 9 and 12. characterised in that the chamber (41 ^ extends around the channel (29) and is provided between the sleeve (27) and the distribution member (31 ).

14. A device for the supply of lubrication oil according to any one of claims 2-13, characterised in that the distribution member (31 ) includes a base portion (32) from which said wall portion (36) extends, wherein the base portion (32) includes a central passage (34), which forms a part of the channel (29) and which has a reduced diameter in relation to the channel (29) upstream and downstream of the central passage (34), and wherein the base portion includes at least two arms (33), which form said wall portions (36)