EP3291914B1 - Grinding roll with a cooling arrangement - Google Patents

Description

The invention relates to a grinding roller shaft with a cooling device for cooling a grinding roller.

For crushing materials such as rocks, ores, coal or other materials usually grinding rollers are used. Known grinding rollers comprise two roller bodies, which rotate in opposite directions to each other and shred material introduced between the grinding rollers.

During the grinding process, in particular at the bearing points of the shaft and on the roller surface, process heat occurs, which ensures heating of the grinding system and thus requires cooling. Usually, the shaft of the grinding roller is cooled by a cooling water circuit in a shaft bore, wherein a coolant is passed through a bore in the grinding roller shaft. Damage caused by deposits and corrosion on the grinding roller shaft and the cooling device is frequently the result of the operation of known cooling devices.

A cooling device of a grinding roller of a roller mill is for example from DE 10 2012 106 527 A1 . DE 197 00 347 A1 . US 4019846 A or CN 104289273 A known. The production cost and the production cost of such known cooling devices for grinding rollers are high, and the assembly, especially in work environments with small mounting space is complex.

On this basis, it is an object of the present invention to provide a grinding roller with a cooling device for cooling the grinding roller, which avoids damage due to corrosion and at the same time is simple and inexpensive to produce and assemble.

This object is achieved by a grinding roller shaft with the features of independent device claim 1. Advantageous developments emerge from the dependent claims.

Grinding roller shaft (12) on which a roller mill (11) is mounted for a roller mill and which is rotatable about its longitudinal axis comprises according to a first aspect of an axial bore in the grinding roller shaft, in which a cooling device is arranged, at least one in the bore arranged between the tube and the inner surface of the bore, a first channel for guiding a coolant and within the tube, a second channel to Guide the coolant is formed, wherein the at least one tube is formed of a plastic.

A pipe formed of plastic has no electrical conductivity and offers the advantage that no corrosion can occur by flowing along the pipe coolant along the pipe. Furthermore, a tube made of plastic has a high temperature resistance, which is advantageous in particular when used in a cooling device of a grinding roller of a roller mill, since during operation of the roller mill, as well as during storage and transport of the cooling device temperatures of about -40 ° C to + 80 ° C, especially -20 ° C to + 40 ° C occur.

In contrast to tubes formed, for example, of metal, a plastic tube has a low thermal conductivity, so that, for example, a coolant flowing through the first channel hardly heats coolant, preferably not at all, flowing in the second channel. The plastic tube isolates the first channel thermally from the second channel, with no additional coating or space between the first channel and the second channel necessary. In particular, the plastic pipe has a wall thickness of 10mm to 30mm and is inelastic.

A plastic tube is also easy and inexpensive to produce. For example, the tube is made of a high-density polyethylene (PE-HD) or a polyvinylidene fluoride (PVDF), which are also particularly inexpensive. Such plastics also have a resistance to chemicals, so that when cleaning the cooling device, in particular with phosphoric acid, no damage to the pipes occurs.

According to a first embodiment, the cooling device has a first tube and a second tube, which is arranged within the first tube, wherein the interior of the second tube forms the second channel for guiding the coolant. In particular, the tubes are arranged coaxially with each other in the bore. A dual-tube cooler provides reliable thermal isolation of the first channel from the second channel, the first channel being disposed between the outer surface of the first tube and the inner surface of the bore of the refining roller shaft. Also, the second tube is preferably formed of a plastic.

According to a further embodiment, the second tube has a smaller diameter than the first tube and is arranged coaxially therewith so that a gap is formed between the tubes. The gap between the two tubes of the cooling device provides additional thermal isolation of the first channel from the second channel, so that a high temperature difference of the coolant in the first channel to the coolant in the second channel is possible.

The cooling device has according to a further embodiment exactly one tube, wherein the interior of the tube forms the second channel. A cooling device with only one tube allows a reduction of the components of the cooling device and thus a cost savings. The assembly of the cooling device in the grinding roller shaft, as well as the maintenance of the cooling device is simplified by a reduced number of components, resulting in a cost and time savings. The reduction of the components of the cooling device to only one tube is made possible, in particular, by the formation of the tube from a plastic, since the use of a plastic tube makes it possible to dispense with additional insulation of the first channel from the second channel.

The second channel forms according to a further embodiment of a return for heated in the first channel coolant. During operation of the cooling device, the coolant flows from a coolant inlet at one end of the bore through the first channel along the inner surface of the bore, wherein the coolant is heated and the grinding roller shaft is cooled. Following the first channel, the coolant flows through the second channel inside the tube back to a coolant outlet. The flow direction of the coolant described has the advantage that the coolant is guided directly after the coolant inlet directly along the surface to be cooled, namely the inner surface of the bore, which allows a particularly efficient cooling.

The tube is arranged according to a further embodiment substantially coaxially with the bore. This allows efficient cooling of the grinding roller shaft, with the coolant being guided along the inner surface of the bore.

According to another embodiment, the outer diameter of the tube over the entire extension of the tube is less than the inner diameter of the bore, so that the first channel between the outer surface of the tube and the inner surface of the bore is formed.

The cooling device has, according to a further embodiment, at least one spacer, which spaces the tube to the inner surface of the bore. This allows centering of the at least one tube of the cooling device in the bore, so that a distance between the tube and the inner surface of the bore is ensured and a flow through the first channel is made possible.

The spacer is substantially annular in shape and attached to the outer tube circumference. Ring-shaped spacers allow easy mounting of the cooling device in the bore. In particular, the annular spacer has projections which are formed as skids and slide during assembly of the tube in the bore on the inner surface of the bore, whereby damage to the inner surface of the bore is avoided. An annular spacer also allows easy centering of the tube in the bore.

The at least one tube has according to a further embodiment at least two separate pipe sections, which are connected to each other via a connecting device. In particular, a plurality of pipe sections are conceivable, which are connected together to form a tube. For example, a pipe 2 to 10, in particular 4 to 6 pipe sections. The pipe sections preferably have the same length, whereby the production of the pipe sections is simplified. A plurality of pipe sections enables easy assembly and disassembly of the cooling device in the grinding roller shaft. In particular, when mounted roll mills, which are used for example in cement plants or open pit / underground mining, the mounting space available for mounting or dismounting of the cooling device is often very small, so that a tube which has approximately the length of the grinding roller shaft, very difficult and time-consuming to assemble. A tube comprising several pipe sections simplifies the assembly and disassembly of the cooling device considerably.

The pipe sections are releasably connected to each other according to another embodiment, which allows a quick disassembly of the individual pipe sections. The connecting device is in particular a screw or clamp connection. The pipe sections are preferably connected to one another via a sleeve, in particular a double sleeve. A sleeve has a small thickness and thus allows a sufficient distance of the connecting means to the inner surface of the bore of the grinding roller shaft. According to a further embodiment, the first channel and the second channel are in fluid communication via a connecting element such that coolant flowing through the first channel flows into the second channel.

The cooling device according to a further embodiment is mounted in the bore such that the cooling device is stationary relative to the grinding roller shaft. During operation of the roller mill, the grinding roller shaft rotates about its longitudinal axis, wherein the cooling device mounted in the bore of the grinding roller shaft rotates with the grinding roller, so that the cooling device and the grinding roller do not move relative to one another.

Description of the drawings

• Fig. 1 zeigt eine schematische Darstellung eines Ausschnitts einer Mahlwalzenwelle mit einer Kühleinrichtung in einer Schnittansicht gemäß einem Ausführungsbeispiel.
• Fig. 2 zeigt eine schematische Darstellung eines Ausschnitts einer Mahlwalzenwelle mit einer Kühleinrichtung einer Schnittansicht gemäß einem weiteren Ausführungsbeispiel.

The invention is explained in more detail below with reference to several embodiments with reference to the accompanying figures.

• Fig. 1 shows a schematic representation of a section of a grinding roller shaft with a cooling device in a sectional view according to an embodiment.
• Fig. 2 shows a schematic representation of a section of a grinding roller shaft with a cooling device of a sectional view according to another embodiment.

Fig. 1 shows a section of a grinding roller shaft 12 in the manner not shown, a grinding roller is mounted. The grinding roller shaft 12 has an axial bore 14 passing through the grinding roller shaft 12. The grinding roller shaft 12 further includes a cooling device 10 disposed in the bore 14. Cooling device 10 includes a first tube 16 disposed internally of bore 14 and coaxial therewith. The outer diameter of first tube 16 is less than the inner diameter of bore 14 such that a first channel is defined between the inner surface of bore 14 and the outer surface of tube 16 18 is formed for guiding a coolant. Coaxially to the first tube, a second tube 20 is arranged. The second tube 20 has a smaller diameter than the first tube 16 and is disposed within the first tube 16, so that between the first tube 16 and the second tube 20, a gap 22 is formed. The interior of the second tube 20 forms a second channel 24 for guiding the coolant. The first pipe 16 and the second tube 20 have the same length and are formed of a plastic.

The first tube 16 and the second tube 20 are each divided into two tube sections 16a, 16b and 20a, 20b, which are formed as separate components. The pipe sections 16a, 16b, 20a and 20b each have the same length, so that the tubes 16 and 20 are divided centrally in the radial direction. The axially juxtaposed pipe sections 16 a, 16 b are connected to each other via a connecting device 46, so that they form the first tube 16. In the same way, the pipe sections 20a and 20b are connected to each other via a connecting device 48 to the second pipe 20, wherein the connecting device 46, 48 is for example a sleeve.

In the first channel 18 between the first tube 16 and the inner surface of the bore 14, a plurality of spacers 36 are further arranged, which space the first tube 16 to the inner surface of the bore 14. The spacers 36 are substantially annular in shape and mounted on the outer periphery of the first tube 16, so that they are rotatably connected to the tube 16. Exemplary are in the embodiment in Fig. 1 four spacers 36 attached. The spacers 36 also have passages for the coolant, so that a flow of the coolant through the first channel 18 is made possible.

The bore 14 through the grinding roller shaft 12 has at its one end a cover 26 which has a substantially circular cross section and through which the bore 14 is sealed against the environment. The cover 26 is followed by a connecting element 28 in the direction of the bore 14. The connecting element 28 allows fluid communication of the first channel 18 and the second channel 24. For this purpose, the connecting element 28 has at least one passage, which allows a flow of coolant from the first channel 18 into the second channel 24. The connecting element 28 allows a flow of the coolant from the first channel 18 into the second channel 24 and at the same time prevents a flow of the coolant from the first channel 18 or the second channel 24 into the intermediate space 22. The connecting element 28 is connected to the first tube 16 and attached to the second tube 20, wherein the connecting element 28 is not applied to the cover 26.

The first tube 16 and the second tube 20 extend from the connecting element 28 to the other end of the bore 14 of the grinding roller shaft 12. The opposite end of the cover 26 of the bore 14 has a coolant connection 30 which in Fig.1 is shown schematically. The coolant port includes a coolant inlet 32 in fluid communication with the first channel 18 and a coolant outlet 34 in fluid communication with the second channel 24.

During operation of the grinding roller, the grinding roller shaft 12 rotates about its central axis, with the cover 26 rotating with the grinding roller shaft 12. The cooling device 10 arranged in the bore 14 of the grinding roller shaft 12 is connected to the grinding roller in such a way that it rotates about the longitudinal axis with the grinding roller during operation of the grinding device. The spacer 36 slides only during assembly of the cooling device on the inner surface of the bore 14th

To cool the grinding roller, coolant flows through the coolant inlet 32 into the first channel 18 along the inner surface of the bore 14, thereby cooling the grinding roller shaft 12 along the bore 14. The heated coolant flows at the end of the bore into the connecting element 28, through which it is passed into the second channel 24. The second channel 24 forms a return of the heated coolant, wherein the gap 22 between the first channel 18 and the second channel 24 prevents heat transfer of the heated coolant of the second channel 24 to the coolant of the first channel 18. It is also possible to reverse the flow direction of the coolant so that coolant flows from a coolant inlet 34 into the second channel 24 and is conducted through the connecting element 28 into the first channel 18, where it flows along the inner surface of the bore 14 and cooling Grinding roller shaft 12 generates.

Fig. 2 shows a further embodiment of a cooling device, wherein the structure of the grinding roller shaft 12 with the bore 14 of the embodiment of Fig. 1 equivalent. In contrast to Fig. 1 has the cooling device 12 from Fig. 2 only a tube 38 which is coaxial with the bore 14 disposed therein. The tube 38 has a smaller diameter than the bore 14 and is arranged centrally within the bore 14. Between the outer circumference of the tube 38 and the inner surface of the bore 14, a first channel 18 is formed, in which the coolant for cooling the inner surface of the bore 14 of the grinding roller shaft 12 flows. Within the tube 38, a second channel 24 is formed for guiding the coolant, which forms a return of the heated coolant. The first channel 18 and the second channel 24 are in the in Fig. 2 illustrated embodiment separated by the tube 38.

At one end of the bore is as with respect to Fig. 1 described a cover 26 rotatably mounted on the grinding roller shaft 12. Adjoining the cover 26 in the direction of the bore 14 is a connecting element 40 which has at least one passage, for example at least one through-bore, which constitutes a fluid connection between the first passage 18 and the second passage 24. The throughbore is preferably centered and has a smaller diameter than the second channel 24, so that a backflow from the second channel 24 into the first channel 18 is avoided. The tube 38 further comprises two pipe sections 38a and 38b, which are formed approximately identically and are arranged side by side in the bore 14. The pipe sections 38a, and 38b are detachably connected to each other via a connection 44, such as a sleeve. By way of example, the tube 38 in the embodiment according to Fig. 2 two pipe sections 38a and 38b, wherein a higher number of pipe sections, for example, 3, 4, 5 or 6 pipe sections would also be conceivable.

The cooling device 10 further has a plurality of spacers 42, which are formed substantially annular. Exemplary are in the embodiment of Fig. 2 arranged four spacers 42 which are mounted circumferentially on the tube 38. The spacers 42 are mounted on the tube 38 so as to be substantially the same distance apart, the spacers 42 being fixed to the tube 38 in a rotationally fixed manner and sliding along the interior of the bore 14 during assembly of the cooler into the grinding roller shaft 12 , At the opposite end of the cover bore 14 is a coolant port 30 according to Fig. 1 with a coolant inlet 32 and a coolant outlet 34.

During operation of the roller mill, coolant flows from the coolant inlet 32 through the first channel 18 along the inner surface of the bore 14 of the grinding roller shaft 12 through the passages in the connecting element 40 into the second channel 24 and exits the cooling device 10 through the coolant outlet 34 Channel 24 flowing heated coolant is in contrast to the embodiment of Fig. 1 only separated by the wall of the tube 38. The flow direction of the coolant is reversible, so that the coolant first flows through the second channel 24 and then through the first channel 18 along the inner surface of the bore 14.

With respect to Fig. 1 described first tube 16, the second tube 20, as well as with reference to Fig. 2 described tube 38 are in particular made of a plastic.

The plastic of the first tube 16 and the second tube 20 according to Fig. 1 , and the tube 38 according to Fig. 2 has in particular a low heat transfer coefficient. Thus, according to the embodiment Fig. 1 made of plastic tubes 16 and 20 for thermal insulation of the tubes 16 and 20 against each other, so that between the first channel 18 and the second channel 24 no heat is transmitted. In the in Fig. 2 described embodiment, the formed of a plastic tube 38 provides it for a thermal insulation of the first channel 14 of the second channel 24, wherein was dispensed with an intermediate space between the channels.

LIST OF REFERENCE NUMBERS

10

cooling device

11

grinding roll

12

Mahlwalzenwelle

14

drilling

16

first pipe

16a

pipe section

16b

pipe section

18

first channel for guiding a coolant

20

second pipe

20a

pipe section

20b

pipe section

22

gap

24

second channel for guiding a coolant

26

cover

28

connecting element

30

Coolant connection

32

Coolant inlet / outlet

34

Coolant outlet / inlet

36

and spacer

38

pipe

38a

first pipe section

38b

second pipe section

40

connecting element

42

and spacer

44

Connection / connection device

46

Connection / connection device

48

Connection / connection device

Claims (14)

1. Grinding roller shaft (12) on which a grinding roller (11) for a rolling mill is mounted and which is rotatable about its longitudinal axis,
   wherein the grinding roller shaft (12) comprises an axial bore (14), in which a cooling device (10) is arranged, comprising at least one pipe (16, 20; 38) which is arranged in the bore (14),
   wherein a first channel(18) for guiding a coolant is formed between the pipe (16, 20; 38) and the inner surface of the bore (14) and a second channel (24) for guiding the coolant is formed inside the pipe (16, 20; 38),
   characterized in that the at least one pipe (16, 20; 38) is made of a plastic.
2. Grinding roller shaft (12) according to Claim 1, wherein the cooling device (10) comprises a first pipe (16) and a second pipe (20), the second pipe (20) being arranged inside the first pipe (16), and the interior of the second pipe (20) forming the second channel (24) for guiding the coolant.
3. Grinding roller shaft (12) according to Claim 2, wherein the second pipe (20) has a smaller diameter than the first pipe (16) and is arranged coaxially to it, so that a gap (22) is formed between the first pipe (16) and the second pipe (20).
4. Grinding roller shaft (12) according to Claim 1, wherein the cooling device (10) comprises precisely one pipe (38) and the interior of the pipe (38) forms the second channel (24).
5. Grinding roller shaft (12) according to one of the preceding claims, wherein the second channel (24) forms a return for coolant heated in the first channel (18) .
6. Grinding roller shaft (12) according to one of the preceding claims, wherein the pipe (16, 20; 38) is arranged substantially coaxially to the bore (14).
7. Grinding roller shaft (12) according to one of the preceding claims, wherein the outer diameter of the pipe (16, 20; 38) over the entire extent of the pipe (16, 20; 38) is smaller than the inner diameter of the bore (14), so that the first channel (18) is formed between the outer surface of the pipe (16, 20; 38) and the inner surface of the bore (14).
8. Grinding roller shaft (12) according to one of the preceding claims, wherein the cooling device (10) comprises at least one spacer (36; 42), which spaces the pipe (16, 20; 38) away from the inner surface of the bore (14).
9. Grinding roller shaft (12) according to Claim 8, wherein the spacer (36; 42) is substantially ringshaped and mounted on the outer pipe circumference.
10. Grinding roller shaft (12) according to one of the preceding claims, wherein the at least one pipe (16, 20; 38) comprises at least two separate pipe segments (16a, 16b, 20a, 20b; 38a, 38b), which are joined together by a connection device (44; 46, 48).
11. Grinding roller shaft (12) according to Claim 10, wherein the pipe segments (16a, 16b, 20a, 20b; 38a, 38b) are releasably joined together.
12. Grinding roller shaft (12) according to Claim 10 or 11, wherein the connection device (44; 46, 48) is a screw or clamp connection.
13. Grinding roller shaft (12) according to one of the preceding claims, wherein the first channel (18) and the second channel (24) are fluidically connected by a connection element (28; 40) such that coolant flowing through the first channel (18) flows into the second channel (24).
14. Grinding roller shaft (12) according to one of the preceding claims, wherein the cooling device (10) is arranged in the bore (14) such that the cooling device (10) is stationary relative to the grinding roller shaft (12).

Images