ERLANDSSON HAAKAN (SE)
BROMAN PATRIK (SE)
ERLANDSSON HAAKAN (SE)
WO2010144046A1 | 2010-12-16 |
US4312424A | 1982-01-26 |
CLAIMS 1. A lubricating system for circulation lubrication of substantial applications of machine parts (1 , 2) subject to heavy loading, comprising an oil sump (4), at least one distribution line (10) of high-pressure type, at least one distribution block (12) for supplying one or more nozzles with lubricating oil, influenced by the oil temperature, where said nozzles are arranged to supply at least one lubrication point with lubricating oil, and at least one return line (5) for bringing oil back from the oil sump (4) to a pump, characterised in that the return line (5) contains means (6) for warming the oil to a first temperature, and that a lubricating oil with a viscosity of at least 5000 cSt at 40°C is pumped from the return line (5) to the lubrication point by a high-pressure pump (7) arranged in the flow direction from the return line to the distribution line (10), at a pump pressure of 125 bar or more, the oil being sprayed directly at said lubrication point via at least one nozzle. 2. The lubricating system according to claim 1 , characterised in that the lubricating oil has a viscosity of 10000 to 22000 cSt at 40°C. 3. The lubricating system according to claim 2, characterised in that the lubricating oil has a viscosity of at least 11000 cSt at 40°C. 4. The lubricating system according to claim 3, characterised in that the lubricating oil has a viscosity of at least 16000 cSt at 40°C. 5. The lubricating system according to any one of claims 1-4, in which said first temperature is within the range 30-60°C. 6. The lubricating system according to claim 5, characterised in that the pump pressure is within the range 125-250 bar. 7. The lubricating system according to claim 6, characterised in that the oil is pumped through a filter before passing out through the nozzle. 8. The lubricating system according to any one of the above claims, in which the distribution block comprises means for warming the oil to a second temperature. 9. The lubricating system according to claim 8, in which said second temperature is within the range 50-80°C. 10. The lubricating system according to claim 8 or 9, in which the distribution block is an oil heater (12) for warming of flowing lubricating oil, comprising at least one heating element (102, 102') and a duct system (103) for conveying the lubricating oil, wherein the duct system (103) runs within a block (104) which is warmed by said at least one heating element (102, 102'), wherein the duct system (103) is arranged to warm the lubricating oil which is conveyed through the duct system ( 03). 11. The lubricating system according to claim 10, in which the duct system (103) comprises at least one duct (105) which runs within the block (104) and which comprises duct portions (106, 106') arranged angularly relative to one another in order to lengthen said at least one duct (105). 12. The lubricating system according to claim 10 or 11 , in which the duct system (103) comprises at least one feed inlet (107) for supply of lubricating oil to the duct system (103), at least one lubricant outlet (108, 108') for delivery of lubricating oil from the duct system (103), wherein the duct system (103) comprises at least one duct (105) comprising at least one feed duct (109) and at least one warming duct (110, 110'), said at least one warming duct (110, 110') and said at least one feed duct (109) are connected to one another, said at least one feed inlet (107) is comprised in said at least one feed duct (109) and said at least one lubricant outlet (108, 108') is comprised in said at least one warming duct (110, 110'). 13. A lubricating system according to claim 12, in which said at least one warming duct (110, 110') runs within the block (104) and comprises duct portions (106, 106') arranged angularly relative to one another in order to lengthen said at least one warming duct (110, 110'). 14. A lubricating system according to claim 13, in which said at least one warming duct (110, 110') runs in at least one loop round said feed duct (109). 15. A lubricating system according to any one of claims 10-14, in which said at least one heating element (102, 102') is arranged within the block (104). 16. A lubricating system according to any one of claims 12-15, in which a lubricating device (111 , 111 ') is connected to each said at least one lubricant outlet (108, 108'). 17. A lubricating system according to any one of claims 12-16, in which a volume-reducing insert (112, 112') is arranged at the centre of at least one of said at least one warming duct (110, 110'). 18. A lubricating system according to any one of claims 12-17, in which said at least one feed duct (109) is only one feed duct (109). 19. A lubricating system according to any one of claims 12-18, in which said at least one warming duct (110, 110') is at least two warming ducts (110, 110') and said at least one lubricant outlet (108, 108') is at least two lubrication outlets (108, 108'). 20. A lubricating system according to claims 18 and 19, in which the duct system (103) comprises at least one distribution duct (113) for distribution of lubricating oil from the feed duct (109) to said at least two warming ducts (110, 110'), wherein said at least two warming ducts (110, 110') are connected to said at least one feed duct (109) via said at least one distribution duct (113). 21. A lubricating system according to any one of claims 10-20, in which the flow of lubricating oil is laminar. 22. A lubricating system according to any one of claims 10-21 , in which the block (104) is made of metal. 23. A lubricating system according to any one of claims 12-22, in which the duct system (103) comprises a feed duct (109) and at least two warming ducts (110, 110'), wherein the duct system (103) comprises a feed inlet (107) for supply of lubricating oil to the feed duct (109) and at least two lubricant outlets (108, 108') for delivery of lubricating oil from said at least two warming ducts (110, 110'), wherein each warming duct (110, 110') runs round the feed duct (109) and comprises at least four duct portions (106, 106') arranged substantially at right angles in relation to one another, and said at least one heating element (102, 102') is arranged within the block (104). 24. A lubricating system according to any one of claims 12-23, in which said at least one feed duct (109) runs from a first end of the block (104) to a second end of the block (104), and the oil heater (12) comprises at least two blocks (104) connected in series such that the outlet from said at least one feed duct (109) in one block connects to the inlet to said at least one feed duct (109) in another block (104). |
TECHNICAL FIELD
The present invention relates to a lubricating system for circulation lubrication of applications of machine parts subject to heavy loading. The system comprises an oil sump, a high-pressure pump for pumping lubricating oil, at least one distribution line for supplying at least one lubrication point with lubricating oil, and at least one return line for bringing oil back from the oil sump to the high- pressure pump, wherein the system comprises means for heating said oil.
BACKGROUND OF THE INVENTION
When lubricating heavy applications subject to heavy loading, such as rolling mills or open gears for grinders used in e.g. the mining industry, lubricating grease has previously been the only alternative. The lubricating grease meets the extremely high demands on lubricants in harsh environments with high temperatures, shock impacts and impurities such as dirt, dust and water. The lubricating grease is distributed to different lubricating points using different central lubrication systems, wherein the lubricating grease is fed to the lubricating point at a certain time interval. Used lubricating grease is collected and led away from the plant for destruction or depositing. Even if the use of lubricating grease provides a satisfactory lubrication, the consumption and the managing of consumed lubricating grease leads to considerable cost for the user.
When lubricating for example steam or gas turbines or corresponding industrial machinery, it is also possible to use a lubricating oil for lubricating bearings or gear drives by using circulation lubrication. It is a known fact that the lubricating oil requires higher viscosity during higher loads. In applications that involve heavy loads, high viscosity lubricating oils must be used, and this viscosity often exceeds the normal values used during circulation lubrication.
Lubricating oil viscosity is measured using the "Centistoke (cSt)" unit, and as this unit is temperature dependent, the viscosity at 40°C is usually stated for comparison purposes. General lubricating oils commonly have a viscosity value between 20 and 80 cSt at 40°C, but viscosity values up to 500 cSt at 40°C may be used at higher loads. The pumpability of the lubricating oil decreases when the viscosity increases, and in the case of lubricating oils where the viscosity exceeds 1 ,000 cSt at 40°C, pumpability is considered so low that oil bath lubrication is used, meaning that the machine parts are immersed in an oil bath. For larger applications, however, oil bath lubrication is not practically applicable. SUMMARY OF THE INVENTION
The purpose of the present invention is to accomplish circulation lubrication of larger machine parts applications during heavy load, such as for example in the mining industry, in order to replace the use of lubricating grease. The present invention also has the advantage of producing an oil spray which originates from highly viscous oil using very high pressure and heating of the oil. The oil spray effectively reaches even machine components that rotate with high rotational speeds. The high viscosity provides efficient lubrication of machine components which are subject to heavy loads.
According to the present invention, the purpose is achieved by a lubricating system for circulation lubrication of larger machine parts applications, during heavy loads, comprising an oil sump, at least one distribution line arranged for supplying at least one lubricating point with lubricating oil and at least one return line arranged for returning the oil, plus one oil pump, wherein the system includes means for heating the oil, wherein a lubricating oil with a viscosity of at least 5,000 cSt at 40°C is pumped from the oil sump via a high-pressure distribution pipe to the lubricating point, wherein the oil is distributed directly via at least one nozzle at said lubrication point. The pump is a high-pressure pump arranged to provide an oil pressure of 200 bar at a location just before the nozzle in the flow direction of the oil. After lubrication, the oil is returned via a return line to the pump (self-flowing).
Preferably, the lubricating oil viscosity is between 10,000 and 22,000 cSt at
40°C. In a preferred embodiment, the lubricating oil has a viscosity of at least 10,000 cSt at 40°C and a pump which provides sufficient power to generate an oil pressure corresponding to 200 bar overpressure is arranged in the high-pressure distribution line in the flow direction of the oil.
The inventor has also discovered a previously unrecognised and/or unidentified problem. The inventor has identified that, partly due to movement speed of the machine parts, problems may occur if the lubricating oil does not completely reach the gear areas that are intended to be lubricated. After innovative work and testing, a solution to this problem has been identified, in the form of a high-pressure pump with sufficient capacity to provide a substantial pressure in the lubricating oil, enabling a nozzle to spray atomised oil directly onto the lubrication areas.
The oil from the return line is preferably pumped through a filter before it reaches the nozzle, and the oil is preferably pumped from the return line to the distribution pipe using pressurised lubricating oil. The return line temperature is preferably kept at approximately 30-60°C and the nozzle temperature is likewise kept at approximately 50-80°C.
DESCRIPTION OF THE INVENTION
LIST OF FIGURES
The present invention will now be described in more detail, by way of example, with reference to a preferred embodiment according to the accompanying drawing, in which:
Fig. 1 shows a schematic view of a gear drive with a lubricating system according to an embodiment of the present invention.
Fig. 2 is a perspective sketch of an embodiment of the oil heater according to the present invention.
Fig. 3-5 are transparent perspective views of the embodiment shown in fig. 2 and viewed from different perspectives.
Fig. 6 is a transparent perspective view of the embodiment shown in fig. 2-5 and viewed from substantially the same perspective as in fig. 3, with some volume- reducing inserts pulled out.
Fig. 7 is a transparent perspective view of the embodiment shown in fig. 2-6 and viewed from substantially the same perspective as in fig. 3 and fig. 6, with a cross-section through a heating channel.
DETAILED DESCRIPTION
The present invention thus relates to a lubricating system where circulating oil is used in for accomplishing a constant flow of lubricating oil of suitable viscosity and pressure, in order to ensure satisfactory lubrication of a gear drive of a larger plant or machine, for example a grinder. With reference to fig. 1 , the lubrication system comprises an oil sump 4 with an outgoing return line 5 and at least one high- pressure distribution pipe 10 for supplying at least one lubrication point with lubricating oil, wherein the oil sump, the return line and the high-pressure distribution line comprises means 6 for heating the oil. A pressure switch may be provided in the high-pressure distribution line in order to ensure that the correct pressure level, at least 125 bar, is being maintained through regulation of the pump 7.
The high-pressure distribution pipe comprises, in its end part closest to the lubricating point, a distribution block 12 where the temperature of the lubricating oil is regulated to the correct level before the lubricating oil, via one or more nozzles evenly distributed over the width of the gear drive, is sprayed using high pressure in the direction of those areas of the gear drive 1 , 2 which are in need of lubrication. The distribution block can also very well comprise flow sensors in order to indicate the oil flow to each nozzle. A surveillance device (not shown) may be arranged to output an alarm in case of a flow reduction. After lubrication, excess oil is collected in the oil sump 4 and returned by gravitation via the oil sump 4 and the return line 5 to the pump 7. The pump may be driven by an electric motor 9 via a gearbox 8. The return line 5 may contain at least one heater 6 arranged to keep the return oil at a suitable temperature of approximately 30-60°C. In the example shown, two heaters of 1 ,500 W each are used to maintain the oil temperature at approximately 30-60°C. The oil sump 4 may contain additional heaters. In the example shown, a total of three heaters, each of 1 ,500 W, are present and intended to heat the lubricating oil to approximately 45°C. One of these is arranged in the oil sump, one is arranged in the return line and one in the distribution block 12. The example shown also contains a pump which pumps the heated oil through at least one filter 11 comprising a filter element using a filter mesh of, for example, 25 micrometer, for filtering and elimination of eventual impurities, after which the lubricating oil is again directed to the high-pressure pipe 10. In the example shown, the system
accommodates 1 ,500 litres of lubricating oil, which is filled up via the oil sump. A suitable viscosity for the example shown is 16,000 cSt at 40°C.
Previously, a viscosity of 1 ,000 cSt at 40°C has been considered the maximum viscosity for oil used in, for example, roller bearings, and if this grade is heated to 30°C, in accordance with the present invention, it has become possible to maintain a highly viscous oil grade at a temperature where the oil still is fluid and does not deteriorate with time. The viscosity will be considerably higher than the viscosity of 2,200 cSt at 40°C that has previously been considered the upper limit for circulating systems. According to the present invention, the oil uses gravity to flow downwards via the return line to the pump. By heating the oil to 40-60°C, and by arranging a high pressure pump with a pump pressure of at least approximately 150-200 bar overpressure, it is possible to pump a highly viscous oil grade through the filter and further through the high-pressure distribution line to the lubricating point without any significant cooling of the oil, and during such a short time that the oil grade does not deteriorate to any great extent. The high-pressure distribution line
10, also referred to as the pressure line 10, may be provided with insulation in order to prevent cooling of the oil and/or to reduce the need for installing additional heaters in the system.
Heaters may be arranged to maintain oil temperature within a first temperature interval at the pump 7 and during the passage through the filter 11 and the distribution line 10. Heaters may be arranged to maintain oil temperature within a second temperature interval at the distribution block 12. The second temperature interval may be equal to or differing from the first. The second temperature interval may be higher than the first.
To accomplish good lubrication at the lubricating point, atomised oil 13 is sprayed, using high pressure, directly towards the lubricating point. By identifying the problem and solving it, through means including but not restricted to selecting a pump with a pump pressure of up to 220 bar overpressure, a system is
accomplished which solves the problem that, by way of introduction, has been identified in the present application, i.e. the problem of distributing highly viscous oil to a lubrication point placed within fast moving and heavily loaded machine parts. A pressure of between 125 and 200 bar should be sufficient for most applications where the movement speed of the machine parts in question does not exceed 15 m/s.
In one embodiment of the lubricating system according to the present invention, the distribution block is an oil heater 12 for heating of flowing lubricating
011, comprising at least one heating element 102, 102' and a duct system 103 for conveying the lubricating oil, which duct system 103 runs within a block 104 which is heated by said at least one heating element 102, 102', and where the duct system 103 thus is adapted to heating the lubricating oil which is conveyed through the duct system 103.
An oil heater 12 for heating of flowing lubricating oil comprises at least one heating element 102, 102' and a duct system 103 for conveying the lubricating oil, wherein the duct system 103 runs within a block 104 which is heated by said at least one heating element 102, 102', the duct system 103 thus being adapted to heating the lubricating oil which is conveyed through the duct system 103.
The oil heater accomplishes heating of flowing lubricating oil. The oil heater accomplishes heating of highly viscous lubricating oil. The oil heater accomplishes heating of lubricating oil subject to high pressure. The oil heater enables spraying of lubricating oil.
Since the oil heater heats flowing lubricating oil, the lubricating oil flows through the duct system 103. This means that heating of lubricating oil occurs during the time that the lubricating oil is in a moving state, i.e. while the lubricating oil is being transported through the duct system 103. The lubricating oil can flow continuously through the duct system 103. The need for heating in a tank containing stationary or very slowly flowing oil can hereby be reduced or eliminated.
By using a duct system 103 arranged inside a block 104 which in turn is heated by at least one heating element 102, 102, the lubricating oil is heated while in a moving state and flowing through the duct system 103. Arranging the duct system 103 inside a block 104 enables the heating of lubricating oil under high pressure. Since the block 104 enables the use of high wall thickness and high resistance, the oil heater 12 will withstand a high pressure, whereby heating of high- pressure lubricating oil becomes a possibility. This achieves the advantage that highly viscous lubricating oil is transported in the duct system 103 while it is being heated. Since lubricating oil is heated while being transported in the duct system 103, instead of being heated in a tank, as in many other cases, highly viscous lubricating oil can be heated in an efficient manner. The reason, at least in part, is that the contact area between lubricating oil and the heat-transmitting surface is larger in the present invention and makes stirring superfluous, at least in part. Since the lubricating oil may be subject to a high pressure, highly viscous lubricating oil that has been heated by the oil heater 12 according to the present invention can be sprayed. The block further enables a large contact area between oil and hot surfaces, which provides efficient heating.
In one embodiment, the duct system 103 comprises at least one duct 105 which runs within the block 104 and which comprises duct portions 106, 106' arranged at angles relative to one another in order to lengthen said at least one duct 105. Since the duct system 103 comprises at least one duct 105 which runs inside the block 104 and which comprises duct portions 106, 106' arranged at angles relative to one another, said at least one duct 105 runs along a winding and extended distance inside the block 104, by which the lubricating oil is led an extended distance inside the block 104. Thereby the retention time of the lubricating oil inside the block 104 is increased, which leads to increased heating of the lubricating oil. Thus, the system enables the heating of the lubricating oil to a higher temperature, and/or the cooling of the temperature of the block 104 while
maintaining the lubricating oil temperature and/or enables the increasing of the lubricating oil flow rate while maintaining the lubricating oil temperature. As said at least one duct 105 runs round inside the block 104 and comprises duct portions 106, 106' which are arranged at angles in relation to one another, wherein the
dimensions of the block 104 can be kept small while the lubricating oil can be heated in an efficient manner, which means that the heating capacity of the oil heater per volume block 104 is high. The duct portions 06, 106' may be arranged angularly, for example by arranging at least one duct 105 so that it is curved and/or angled. In this way, said at least one duct 105 may have a winding form inside the block 104 so that the length of said at least one duct 104 inside the block increases, thereby extending the distance that the lubricating oil is led round inside the block 104. The fact that said at least one duct 105 comprises duct portions 106, 106' arranged angularly in relation to each other means, in the cases where the duct system 103 comprises at least one feed inlet 107 for supply of lubricating oil to the duct system 103 and at least one lubricant outlet 108, 108' for delivery of lubricating oil from the duct system 103, that said at least one duct 105 has a length which exceeds the shortest distance between said at least one feed inlet 107 and said at least one lubricant outlet 108, 108'. In this way, said at least one duct 105 runs an extended distance in relation to the nearest distance between said at least one feed inlet 107 and said at least one lubricant outlet 108, 108'. Said at least one duct 105 may be longer than the length of the block. Said at least one duct 105 may be longer than the length of the block across its longitudinal direction.
In one embodiment the duct system 103 comprises at least one feed inlet
107 for supply of lubricating oil to the duct system 03, at least one lubricant outlet 108, 108' for delivery of lubricating oil from the duct system 103, wherein the duct system 103 comprises at least one duct 105 comprising at least one feed duct 109 and at least one heating duct 110, 110', said at least one heating duct 110, 110', and said at least one feed duct 109 are connected to one another, said at least one feed inlet 107 is comprised in said at least one feed duct 109 and said at least one lubricant outlet 108, 108' is comprised in said at least one heating duct 110, 110'. The lubricating oil is supplied to the feed duct 109 through the feed inlet 107 and is then led over through said at least one heating duct 110, 110', from which the lubricating oil is led out through said at least one lubricant outlet 108, 108'.
In one embodiment, said at least one heating duct 110, 110' runs within the block 104 and comprises duct portions 106, 106' arranged at angles relative to one another in order to lengthen said at least one heating duct 110, 110'. Since said at least one heating duct 110, 110' comprises duct portions 106, 106' arranged angularly in relation to one another, said at least one heating duct 110, 110' is extended. In this way, said at least one heating duct 110, 110' can be designed to accomplish optimal heating, for example by being extended as much as possible relative to the size of the block 104. Simultaneously, said at least one the feed duct 109 may be designed to accomplish optimal feeding of lubricating oil, for example by not including any, or only a few curves and/or angles, which reduces losses in the duct system 103. Said at least one feed duct 109 may also be optimised for the feeding of lubricating oil by having a relatively large diameter, which also reduces losses in the duct system 103. The fact that said at least one heating duct 110, 110' comprises duct portions 106, 106' which are arranged angularly in relation to one another means that said at least one heating duct 110, 110' has a length which exceeds the shortest distance between said at least one feed duct 109 and said at least one lubricant outlet 108, 108'. In this way, said at least one heating duct 110, 110' runs an extended distance in relation to the nearest distance between said at least one feed duct 109 and said at least one lubricant outlet 108, 108'. Said at least one heating duct 110, 110' may be longer than the length of the block. Said at least one heating duct 110, 110' may be longer than the length of the block across its longitudinal direction.
In one embodiment, said at least one heating duct 110, 1 10' runs in at least one loop round said feed duct 109. Since said at least one heating duct 110, 110' runs in at least one loop round said at least one feed duct 109, the block 104 can be made compact while the length of said at least one heating duct 110, 110' may still be substantial. In this way, the dimensions of the block 104 may be kept small while efficient heating of the lubricating oil is accomplished. Said at least one heating duct 110, 110' may run in at least one 360° loop round said feed duct 109.
In one embodiment, said at least one heating element 102, 102' is arranged inside the block 104. The heating element 102, 102' being arranged inside the block 04 means that the block 104 substantially surrounds said at least one heating element 102, 102'. By arranging said at least one heating element 102, 102' inside the block 104, efficient heating of the block 104 is obtained, which in turn heats the lubricating oil. By arranging said at least one heating element 102, 102' inside the block 104, a large amount of the heat generated by the heating element is transferred to the block 104, resulting in efficient heating, particularly when compared to a heating element arranged on the surface of the block 104. Said at least one heating element 102, 102' may be arranged in at least one notch 114, 114' in the block 104. In this way, said at least one heating element 102, 102' can be inserted in said at least one notch 114, 114'. Said at least one notch 114, 114' may be at least one recess. The recess may be cylindrical or tapered, which means that one or more rod-shaped or tapered heating elements 102, 102' preferably may be used. Said at least one heating element 102, 102' may be at least two heating element 102, 102', wherein said at least two heating elements 102, 102' are arranged in different locations inside the block 104 in order to distribute the heat more evenly. By placing two or more heating elements 102, 102' well apart inside the block 104, a more even temperature may be obtained and thus, the temperature of the lubricating oil can be more controlled. Alternatively, different parts of the block 04 may be heated to different temperatures, thereby heating lubricating oil to different temperatures, resulting in lubricating oil that leaves different lubricant outlets may be regulated to different temperatures. Said at least one heating element 102, 102' may be at least one electric heating element, which means that the block 104 is heated using electricity. Said at least one heating element 102, 102' may be at least one electric heater cartridge.
In one embodiment, a lubricating device 111 , 111 ' is connected to each said at least one lubricant outlet 08, 08'. A lubricating device 111 , 1 1' may be connected to said at least one lubricant outlet 108, 108' in order to accomplish lubrication of at least one component, for example a rolling mill or an open gear. The lubricating device may be a spraying nozzle or an orifice or similar, preferably a spraying nozzle. In one embodiment a volume-reducing insert 112, 112' is arranged at the centre of at least one of said at least one heating duct 110, 110'. By the
arrangement of one volume-reducing insert 112, 112' at the centre of said at least one heating duct 110, 110' the passage of lubricating oil around the insert 112, 112' is enabled. The volume-reducing insert 112, 112' limits the volume of lubricating oil in said at least one heating duct 1 10, 110' while the contact area between the lubricating oil and said at least one heating duct 110, 110' is unchanged. The heat conduction is thereby improved which leads to increased temperature of the lubricating oil. Thus, the heating of the lubricating oil is made more efficient. Said volume-reducing insert 112, 112' may have the shape of a rod. Said volume- reducing insert 112, 112' may consequently be a rod. Said volume-reducing insert 112, 112' may be cylindrical. Said volume-reducing insert 112, 112' may
consequently be a cylindrical rod.
In one embodiment, said at least one feed duct 109 is precisely one feed duct 109. By only having one feed duct 109, said feed duct can easily be optimised to function as a main duct for receiving lubricating oil and for transporting said oil further to other parts of the duct system 103. Since only one feed duct 109 occurs, said duct can be made larger, for example by increasing its diameter and thereby reducing losses.
In one embodiment, said at least one heating duct 110, 110' comprises at least two heating ducts 110, 110' and said at least one lubricant outlet 108, 108' comprises at least two lubricant outlets 108, 108'. By using at least two lubricant outlets 108, 108' it becomes possible to lubricate two or more components with an oil heater 12. Alternatively, one component may be lubricated in several places using one oil heater 12. By providing the oil heater 12 with at least two lubricant outlets 108, 108' the oil heater 12 is capable of distributing lubricating oil to two or more lubricating points. Said at least two heating ducts 110, 110' are connected to said at least one feed duct 109. By providing the oil heater 12 with two or more heating ducts 110, 110' the lubricating oil is divided into two or more streams during heating, which means that the contact area between the lubricating oil and said at least one heating duct 110, 110' increases in relation to the volume of lubricating oil, whereby heating is made more efficient. In the case of for example wide gear drives it is an advantage to have several spray nozzles arranged next to one another to cover lubrication of the entire gear drive width in an efficient manner. The oil heater 12 has the advantage of being able to heat lubricating oil and distribute lubricating oil to two or more lubricating points.
In one embodiment, where said at least one feed duct 109 comprises precisely one feed duct 109 and said at least one heating duct 110, 110' comprise at least two heating ducts 110, 110', the duct system 103 comprises at least one distribution duct 113 for distributing lubricating oil from the feed duct 109 to said at least two heating ducts 110, 110', where said at least two heating ducts 110, 110' are connected to said at least one feed duct 109 via said at least one distribution duct 113. Using said at least one distribution duct 113, lubricating oil from the feed duct 109 is transferred to the heating ducts 110, 110' and lubricating oil is distributed between the heating ducts 110, 110'.
In one embodiment, the lubricating oil is subject to a pressure of at least 50 bar. By subjecting the lubricating oil to a high pressure, such as at least 125 bar, the heated lubricating oil can be sprayed onto the components that are intended to be lubricated. The lubricating oil may be subject to a pressure of at least 125 bar, such as at least 150 bar. In one embodiment, the lubricating oil is subject to a pressure of 250 bar maximum, such as 220 bar maximum, such as 200 bar maximum.
In one embodiment, the flow of lubricating oil is laminar. In one embodiment, the flow of lubricating oil is laminar through the oil heater (12). In one embodiment, the flow of lubricating oil is laminar through the duct system (103). The laminar flow of the lubricating oil is related to the fact that the lubricating oil is highly viscous. Whether or not a laminar or turbulent flow occurs is dependent on the flow rate of the lubricating oil, the density of the lubricating oil and the viscosity of the lubricating oil. The density of the lubricating oil is practically constant at the temperatures that are used in the field of lubrication using the present invention. The occurrence of laminar flow is thereby in principle determined by the flow rate of the lubricating oil and the density of the lubricating oil. When using highly viscous lubricating oil the flow is laminar at the flow rates that are possibly to apply during lubrication using the present invention. The lubricating oil may thus be highly viscous lubricating oil. The lubricating oil may have a viscosity of at least 5,000 cSt at 40°C, such as at least
10,000 cSt at 40°C, such as at least 11 ,000 cSt at 40°C, such as at least 16,000 cSt at 40°C. In one embodiment, the lubricating oil has a viscosity of 22,000 cSt maximum at 40°C. In one embodiment, the block 104 is a metal block. By using a metal block 104, several advantages are obtained, such as good thermal conduction properties, good ability to withstand high pressures, simple machining, i.e. manufacturing of the block by using methods such as, for example, drilling. The metal may be selected from steel, copper, aluminium and titanium. The metal may be steel, such as stainless steel. Steel provides the advantages that have been presented above as regards metals, and steel is also relatively cheap. Stainless steel is also highly resistant to corrosion.
In one embodiment, an oil heater 12 is described, wherein the duct system 103 comprises a feed duct 109 and at least two heating ducts 110, 110', wherein the duct system 103 comprises a feed inlet 107 for the purpose of supplying lubricating oil to the feed duct 09 and at least two lubricant outlet 108, 108' for delivery of lubricating oil from said at least two heating ducts 110, 110', wherein each heating duct 110, 110' runs round the feed duct 109 and comprises at least four duct portions 106, 106' arranged substantially at right angles to one another, and wherein said at least one heating element 102, 102' is arranged inside the block 104. Each heating duct 110, 110' runs preferably round the feed duct 109 substantially in one plane at right angle to the longitudinal direction of the feed duct 109.
In one embodiment, an oil heater 12 is described, wherein said at least one feed duct 109 runs from a first end of the block 104 to a second end of the block 104 and the oil heater 12 comprises at least two blocks 104 connected in series such that the outlet from said at least one feed duct 109 in one block connects to the inlet to said at least one feed duct 09 in another block 04. In this way, two or more blocks 104 may be connected in series in order to lubricate larger components that require lubrication in several places, or in order to lubricate several components. By connecting the feed outlet 115 in one block to the feed inlet 107 in another block, lubricating oil is transported further from the first block to the second block. In this way, several blocks 104 may be connected to form a larger unit, which means that a larger number of lubricant outlets 108, 108' may be obtained in a simple way using an oil heater 12. It is thereby possible to lubricate a larger number of lubricating points or a wide lubrication point in an easy way, using a lubricating system that, for example, only needs to contain one pump. It is of course possible to use a large block that contains a large number of lubricant outlets to lubricate several lubrication points, and instead connect two or more smaller blocks that contain a lower number of lubricant outlets, which will provide flexibility and cost reductions in the areas of, for example, manufacturing and transport.
The oil heater 12 may be provided with at least one flow measuring duct 116, 116' for connecting at least one flow meter to said at least one flow measuring duct 116, 116'. Said at least one distribution duct 113 and said at least one feed duct 109 may be connected to one another via said at least one flow measuring duct 116, 116'.
The oil heater may be provided with at least one temperature measuring duct 117 connected to at least one of said at least one heating duct 110, 110'. Said at least one temperature measuring duct 117 may be connected to said at least one heating duct 110, 110' in the vicinity of said at least one lubricant outlet 108, 108'. Each said at least one temperature measuring duct 117 may discharge into a temperature measuring outlet.
Said at least one duct 109 may comprise cylindrical portions, i.e. portions that have the shapes of cylinders. In this way, said at least one duct 109 may comprise portions that each form cylindrical holes in the block 104. Said cylindrical portions may have been provided by method of drilling, whereby the cylindrical portions assume the shape of a cylinder. In the same way, each of said at least one feed duct 109, said at least one heating duct 110, 110', said at least one distribution duct 113, said at least one flow measuring duct 116, 116' and said at least one temperature measuring duct 117 may comprise one or more cylindrical portions, which may have been provided by method of drilling. In a similar way, each of the duct portions 106, 106' may be a cylindrical portion, which may have been accomplished by method of drilling. The duct portions 106, 106' can thereby be cylindrical.
The lubricating oil may be heated continuously. The lubricating oil may be heated to a temperature of 50 to 80°C. This temperature is a suitable temperature for lubricating the components that are intended to be lubricated by using the oil heater according to the present invention, in particular for spraying lubricating oil.
The block 104 may substantially be a cuboid. This means that the block 104 mainly has the shape of a cuboid, but edges and corners of the cuboid may be bevelled. This provides advantages in the fields of handling and manufacturing as the block will be easy to clamp when using, for example, machining tools. In this description, a block refers to a piece which, with the exception of the provided ducts, notches and fixings, substantially is solid. The block may be divided into two or more partial blocks which are joined together to a larger block. The dividing into partial blocks may facilitate manufacturing of the oil heater. Dividing into partial blocks causes a weakening of the block and impaired resistance against high pressure. The block is preferably made in one piece only and is substantially solid, with the exception of the ducts, notches and fixings provided in the piece.
An oil heater according to the description above may be manufactured by a method for manufacturing an oil heater, comprising the step of drilling at least one duct from said solid block. By drilling at least one duct, such as the previously mentioned feed duct, heating duct, distribution duct, flow measuring duct and temperature measuring duct, at least one duct inside an otherwise solid block is obtained. This provides high strength and an oil heater which can resist high pressures. Additionally, drilling of ducts is a relatively simple method for
accomplishing a duct system which is contained inside a block.
A specific embodiment of an oil heater according to the present invention will now be described, with references to the figures 2-7.
Fig. 2-7 shows an oil heater 12 for the purpose of heating flowing lubricating oil, the oil heater comprising a block 104 incorporating a duct system 103, intended for transporting the lubricating oil. The block 104 has the shape of a cuboid. The oil heater 12 comprises six heating elements 102, 102' arranged inside the block 104. The duct system 103 comprises one feed duct 109, two flow measuring ducts 114, 114', one distribution duct 113 and two heating ducts 110, 110'. The feed duct 109 runs through the block 104 from one of the short sides of the block 104 to the other short side of the block 104. Oil is introduced to the feed duct 109 through a feed inlet 107. A first flow measuring duct (forward pipe) runs from the feed duct 109 to the upper side of the block 104. A second flow measuring duct (return line) runs from the upper side of the block 104 to the distribution duct 113. A flow meter connects the first flow measuring duct to the second flow measuring duct. The two heating ducts 0, 0' run from the distribution duct 113 to respective lubricant outlets 108, 108'. Each lubricant outlet 108, 108' are connected to a lubricating device 111 , 111 '. The heating ducts 110, 110' run in loops round the feed duct 109. Each heating duct 110, 110' runs more than two revolutions round the feed duct 109. A temperature measuring duct 117 runs from one short side of the block 104 to one of the heating ducts 110. The temperature measuring duct 117 is connected to the heating duct 110 in the vicinity of the lubricant outlet 108 in order to enable measuring the temperature of the oil just before the oil leaves the heating duct 1 10 and is led to the lubricating device 111. Thus, lubricating oil is transported through the parts of the duct system 03 in the order of the feed duct 109, the first flow measuring duct, the second flow measuring duct, the distribution duct 113 and then the two heating ducts 110, 110'. Each heating duct 110, 110' comprises a number of straight duct portions 106, 106' arranged at a right angle in relation to one another. Each heating duct 110, 110' will in this way form a quadratic spiral around the feed duct 109. The ducts, i.e. the feed duct 109, the flow measuring ducts 114, 1 14', the distribution duct 113 and the heating ducts 110, 110' including the duct portions 106, 106' in the heating duct 110, 110', are drilled from the block 104. Since the drilled ducts 109, 114, 114', 110. 110', 113, 106, 106', 117 run all the way to the sides of the block 104, the openings 118, 118' which are not intended for receiving or distributing lubricating oil are provided with closing devices 119, 119', for example in the form of threaded plugs which are screwed into the threaded portions of the ducts. The closing devices 119, 119' which seal the duct portions 106, 106' in the heating ducts 110, 110' are provided with volume-reducing inserts 112, 112' in the shape of rods that are arranged in the centre of the duct portions 106, 106'. The heating elements 102, 102' are arranged in drilled holes 114, 114' in the block 104 and distributed in the block 104. The heating elements 102, 102' are placed in the vicinity of the heating ducts 110, 110' and are substantially parallel to the loops of the heating ducts 0, 10'. Since the feed duct 109 runs straight through the block 104 it is easy to connect an additional block in series with a first block or to connect several blocks in series.
List of embodiments
Point 1. A lubrication system for circulation lubrication of substantial applications of machine parts (1 , 2) subject to heavy loading, comprising an oil sump (4), at least one distribution line (10) of high-pressure type, at least one distribution block (12) for supplying one or more nozzles with lubricating oil, where said nozzles are arranged to supply at least one lubrication point with lubricating oil, and at least one return line (5) for bringing oil back from the oil sump (4) to a pump,
characterised in that the return line (5) contains means (6) for warming the oil to a first temperature, and that a lubricating oil with a viscosity of at least 5,000 cSt at 40°C is pumped from the return line (5) to the lubricating point by a high-pressure pump (7) arranged in the flow direction from the return line to the distribution line (10), at a pump pressure of 125 bar or more, the oil being sprayed directly at said lubrication point via at least one nozzle.
Point 2. The lubrication system according to point 1 , characterised in that the lubricating oil has a viscosity of 10,000 to 22,000 cSt at 40°C.
Point 3. The lubricating system according to point 2, characterised in that the lubricating oil has a viscosity of at least 11 ,000 cSt at 40°C.
Point 4. The lubricating system according to point 3, characterised in that the lubricating oil has a viscosity of at least 16,000 cSt at 40°C.
Point 5. The lubricating system according to any one of points 1-4, where said first temperature is within the range 30-60°C.
Point 6. The lubricating system according to point 5, characterised in that the pump pressure is in the 125-250 range bar.
Point 7. The lubricating system according to point 6, characterised in that the oil is pumped through a filter before passing out through the nozzle.
Point 8. The lubricating system according to any one of the above points, in which the distribution block comprises means for warming the oil to a second temperature.
Point 9. The lubricating system according to point 8, in which said second temperature is within the range 50-80°C.
Point 10. The lubricating system according to point 8 or 9, in which the distribution block is an oil heater (12) for warming flowing lubricating oil, comprising at least one heating element (102, 102') and a duct system (103) for conveying the lubricating oil, wherein the duct system (103) runs within a block (104) which is warmed by said at least one heating element (102, 102'), wherein the duct system (103) is arranged to warm the lubricating oil which is conveyed through the duct system (103).
Point 11. An oil heater (12) for warming of flowing lubricating oil, comprising at least one heating element (102, 102') and a duct system (103) for conveying the lubricating oil, wherein the duct system (103) runs within a block (104) which is warmed by said at least one heating element (102, 102'), wherein the duct system (103) is adapted in order to warm the lubricating oil which is conveyed through the duct system (103).
Point 12. The oil heater according to point 11 , in which the duct system (103) comprises at least one duct (105) which runs within the block (104) and which comprises duct portions (106, 106') arranged angularly relative to one another in order to lengthen said at least one duct (105).
Point 13. The oil heater according to point 11 or 12, in which the duct system (103) comprises at least one feed inlet (107) for supply of lubricating oil to the duct system (103), at least one lubricant outlet (108, 108') for delivery of lubricating oil from the duct system (103), wherein the duct system (103) comprises at least one duct (105) comprising at least one feed duct (109) and at least one warming duct (110, 110'), wherein said at least one warming duct (110, 110') and said at least one feed duct (109) are connected to one another, said at least one feed inlet (107) is comprised in said at least one feed duct (109) and said at least one lubricant outlet (108, 108') is comprised in said at least one warming duct (1 10, 110').
Point 14. The oil heater according to point 13, in which said at least one warming duct (110, 110') runs within the block (104) and comprises duct portions (106, 106') arranged angularly relative to one another in order to lengthen said at least one warming duct (110, 110').
Point 15. The oil heater according to claim 14, in which said at least one warming duct (110, 110') runs in at least one loop round said feed duct (109).
Point 16. The oil heater according to any one of points 1 1-15, in which said at least one heating element (102, 102') is arranged within the block (104).
Point 17. The oil heater according to any one of points 13-16, in which a lubricating device (111 , 111 ') is connected to each said at least one lubricant outlet (108, 108').
Point 18. The oil heater according to any one of points 13-17, in which a volume-reducing insert (112, 112') is arranged at the centre of at least one of said at least one warming duct (110, 110').
Point 19. The oil heater according to any one of the points 13-18, in which said at least one feed duct (109) is only one feed duct (109).
Point 20. The oil heater according to any one of the points 13-19, in which said at least one warming duct (1 10, 110') is at least two warming ducts (110, 110') and said at least one lubricant outlet (108, 108') is at least two lubrication outlets (108, 108').
Point 21. The oil heater according to points 19 and 20, in which the duct system (103) comprises at least one distribution duct (113) for distribution of lubricating oil from the feed duct (109) to said at least two warming ducts (110, 110'), wherein said at least two warming ducts (110, 110') are connected to said at least one feed duct (109) via said at least one distribution duct (113).
Point 22. The oil heater according to any of the points 11-21 , in which the lubricating oil is subject to a pressure which is at least 50 bar, such as at least 100 bar, such as at least 125 bar, such as at least 150 bar.
Point 23. The oil heater according to any one of the points 11-22, in which the flow of lubricating oil is laminar.
Point 24. The oil heater according to any one of the points 1 1-23, in which the block (104) is made of metal.
Point 25. The oil heater according to any one of the points 13-24, in which the duct system (103) comprises a feed duct (109) and at least two warming ducts (110, 110'), wherein the duct system (103) comprises a feed inlet (107) for supply of lubricating oil to the feed duct (109) and at least two lubricant outlets (108, 108') for delivery of lubricating oil from said at least two warming ducts (110, 1 10'), wherein each warming duct (110, 110') runs round the feed duct (109) and comprises at least four duct portions (106, 106') arranged substantially at right angles in relation to one another, and wherein said at least one heating element (102, 102') is arranged within the block (104).
Point 26. The oil heater according to any one of points 13-25, in which said at least one feed duct (109) runs from a first end of the block (104) to a second end of the block (104), and the oil heater ( 2) comprises at least two blocks (104) connected in series such that the outlet from said at least one feed duct (109) in one block connects to the inlet to said at least one feed duct (109) in another block (104).
Point 27. A method for providing an oil heater according to any of the points
11-26, said method comprising the step of drilling said at least one duct from a solid block.
Point 28. A lubricating system according to any of the points 1-9, in which the distribution block is an oil heater (12) according to any of the points 1 1-26.