COMMINUTING APPARATUS WITH COOLING DEVICE AND METHOD OF OPERATING THE SAME

Abstract

A comminuting apparatus adapted to carry out a comminuting process comprising a comminuting rotor which is mounted to a machine frame and which has a plurality of comminuting tools at its periphery, wherein the comminuting rotor is arranged in a comminuting chamber for receiving comminution material and is adapted to comminute the material in the comminuting chamber, further including a cooling device adapted to introduce a liquid coolant including at least 80% water into the comminuting chamber and including a control device for controlling the cooling device to set a rate of introduction of the coolant into the comminuting chamber. The comminuting apparatus according to the invention is distinguished in that the control device is designed and configured to adapt a rate of introduction of the liquid water-based coolant into the comminuting process to an operating parameter of the apparatus, that is dependent on the quantitative throughput of the comminution material, in such a way that more than 60% of the cooling capacity introduced into the comminution material is provided by the latent heat of the liquid water-based coolant. The invention further concerns a method of operating an apparatus.

Claims

1-28. (canceled)

29. A comminuting apparatus to carry out a comminuting process, the apparatus comprising: a comminuting rotor mounted to a machine frame and which has a plurality of comminuting tools at a periphery, wherein the comminuting rotor is arranged in a comminuting chamber to receive comminution material, and is adapted to comminute the material in the comminuting chamber, a cooling device to introduce a liquid coolant having at least 80% water by weight into the comminuting chamber, a control device to control the cooling device to set a rate of introduction of the coolant into the comminuting chamber, and wherein the control device is configured to adapt a rate of introduction of the liquid water-based coolant into the comminuting process to an operating parameter of the apparatus, that is dependent on a quantitative throughput of the comminution material, in particular a volume throughput, a mass throughput of the comminution material, and/or a drive power of a rotor drive such that more than 60% a cooling capacity introduced into the comminution material is provided by latent heat of the liquid water-based coolant.

30. The comminuting apparatus as set forth in claim 29, wherein the control device is configured to implement adaptation of the rate of introduction of the coolant to the quantitative throughput of the comminution material into the comminuting process such that more than 80% of the coolant introduced upon cooling of the comminution material changes from liquid to vaporous phase.

31. The comminuting apparatus as set forth in claim 29, wherein the cooling device includes a connecting device to connect to a coolant conduit network and/or to connect to a coolant reservoir, and a coolant nozzle device to introduce the coolant into the comminuting process or the comminuting chamber, wherein the control device to control the rate of introduction of the coolant into the comminuting chamber controls at least one valve device of the coolant and/or at least one coolant pump.

32. The comminuting apparatus as set forth in claim 31, wherein the coolant nozzle device is adapted to apply the coolant to the rotor and/or the material to be comminuted.

33. The comminuting apparatus as set forth in claim 31, wherein the coolant nozzle device is adapted to introduce the coolant in a form of a mist into the comminuting process, wherein mist droplets of the coolant are of a diameter <100 μm.

34. The comminuting apparatus as set forth in claim 31, wherein the coolant nozzle device has a plurality of nozzles arranged in spaced relationship with a longitudinal axis of the rotor on the machine frame of the comminuting machine and which are arranged above the rotor in an installed position to introduce the coolant.

35. The comminuting apparatus as set forth in claim 31, wherein the coolant nozzle device has a plurality of nozzles arranged in spaced relationship with a longitudinal axis of the rotor at the periphery thereof.

36. The comminuting apparatus as set forth in claim 29, further comprising: at least one temperature sensor to detect a temperature of the comminuted material, wherein the control device is adapted to provide for closed-loop control to a predetermined set point temperature or a predetermined set point temperature range of the comminuted material with a setting variable establishing the rate of introduction of the coolant.

37. The comminuting apparatus as set forth in claim 29, further comprising: at least one temperature sensor to detect a temperature at the rotor, wherein the control device is adapted to provide for closed-loop control to a predetermined set point temperature or a predetermined set point temperature range of the rotor with a setting variable establishing the rate of introduction of the coolant.

38. The comminuting apparatus as set forth in claim 29, further comprising: at least one moisture sensor to detect a moisture content of the comminuted material, wherein the control device is adapted to provide for closed-loop control to a predetermined set point moisture content or a predetermined set point moisture content range of the comminuted material with a setting variable establishing the rate of introduction of the coolant.

39. The comminuting apparatus as set forth in claim 38, wherein the closed-loop control includes temperature and the moisture content of the comminuted material as closed loop control variables, and is designed as multi-variable closed-loop control and the respective set point value or set point range of the comminuted material are subjected to closed-loop control with a setting variable establishing the rate of introduction of the coolant.

40. The comminuting apparatus as set forth in claim 29, further comprising: a plurality of mutually spaced temperature sensors to detect a respective temperature in the comminuted material, wherein closed-loop control is carried out in dependence on the respective temperatures detected by the temperature sensors.

41. A comminuting apparatus as set forth in claim 29, further comprising: an extraction device adapted for at least partially suck away water vapor which develops during cooling of the material to be comminuted.

42. The comminuting apparatus as set forth in claim 29, further comprising: at least one moisture sensor to measure a moisture content of the material to be comminuted, and the rate of introduction of the coolant is adjusted in dependence thereon as a control variable.

43. A method of cooling comminution material in a comminuting apparatus to carry out a comminuting process, comprising: disposing a comminution material in a comminuting chamber of the comminuting apparatus, comminuting the comminution material with comminuting tools mounted at a periphery of a comminuting rotor, during comminuting of the comminution material, introducing a liquid coolant having at least 80% water into the comminuting chamber, and adapting a rate of introduction of the liquid water-based coolant into the comminuting process to an operating parameter of the apparatus, that is dependent on a quantitative throughput of the comminution material, in particular a volume throughput, a mass throughput of the comminution material, and/or a drive power of a rotor drive such that more than 60% of a cooling capacity introduced into the comminution material is provided by latent heat of the liquid water-based coolant.

44. The method as set forth in claim 43, wherein adaptation of the rate of introduction of the coolant to the quantitative throughput of the comminution material into the comminuting process is carried out such that more than 80% of the coolant introduced upon cooling of the comminution material changes from liquid to vaporous phase.

45. The method as set forth in claim 43, further comprising: measuring a temperature of the comminuted material, and subjecting the temperature to closed-loop control to a predetermined set point temperature or a set point temperature range of the comminuted material with a setting variable establishing the rate of introduction of the coolant.

46. The method as set forth in claim 45, further comprising: detecting a respective temperature of the comminuted material by a plurality of mutually spaced temperature sensors, and the closed-loop control is carried out in dependence on the respective temperatures detected by the temperature sensors.

47. The method as set forth in claim 43, further comprising: measuring a temperature of the rotor, and subjecting the temperature to closed-loop control to a predetermined set point temperature or a set point temperature range of the rotor with a setting variable establishing the rate of introduction of the coolant.

48. The method as set forth in claim 43, further comprising: measuring a moisture content of the comminuted material, and subjecting the moisture content to closed-loop control to a predetermined set point moisture content or a set point moisture range of the comminuted material with a setting variable establishing the rate of introduction of the coolant.

49. The method as set forth in claim 48, wherein the closed-loop control includes temperature and the moisture content of the comminuted material as closed loop control variables, and is designed as multi-variable closed-loop control and the respective set point value or set point range of the comminuted material are subjected to closed-loop control with a setting variable establishing the rate of introduction of the coolant.

50. The method as set forth in claim 43, wherein introduction of the coolant is carried out by way of a plurality of nozzles arranged in spaced relationship with the longitudinal axis of the rotor on a machine frame of the comminuting machine and above the rotor in the installed position.

51. The method as set forth in claim 43, wherein introduction of the coolant is carried out by a plurality of nozzles arranged in spaced relationship with a longitudinal axis of the rotor at the periphery thereof.

52. The method as set forth in claim 43, further comprising: applying the coolant to the rotor and/or to the material to be comminuted.

53. The method as set forth in claim 43, wherein the coolant is introduced in a form of a mist into the comminuting process, wherein mist droplets of the coolant are of a diameter <100 μm.

54. The method as set forth in claim 43, wherein the rate of introduction of the coolant is set as a setting variable of the closed-loop control by a coolant valve device.

55. The method as set forth in claim 43, further comprising: at least partially sucking away water vapor which develops during cooling of the comminuted material.

56. The method as set forth in claim 43, further comprising: measuring a moisture content of the material to be comminuted, and the rate of introduction of the coolant subjected to closed-loop control in dependence thereon as a control variable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The invention is described in greater detail hereinafter by the description of some embodiments of the comminuting apparatus according to the invention and the method according to the invention with reference to the accompanying Figures in which:

[0048] FIG. 1a shows a view of a comminuting apparatus according to the invention,

[0049] FIG. 1b shows a diagrammatic functional view illustrating the structure of a comminuting apparatus according to the invention,

[0050] FIG. 2 shows a flow chart of the comminuting process of the comminuting apparatus of FIG. 1a, b,

[0051] FIG. 3 to describe the method according to the invention of cooling comminution material shows a block circuit diagram of a closed-loop control circuit for one-point control in carrying out the method according to the invention,

[0052] FIG. 4 shows a block circuit diagram of a further closed-loop control circuit with a two-point control for carrying out the method according to the invention,

[0053] FIG. 5 shows a block circuit diagram of a further closed-loop control circuit of a time control for carrying out the method according to the invention, and

[0054] FIG. 6 shows a block circuit diagram of a closed-loop control for carrying out the method according to the invention, in which a multiplicity of operating parameters are used to establish the closed-loop control, besides the reference and closed-loop variable.

DETAILED DESCRTIPTION

[0055] FIG. 1a shows a perspective view of a comminuting apparatus 1 designed according to the invention. A comminuting rotor 14 is mounted in the region of its two longitudinal ends to a machine housing 10, wherein the rotor 14 is moved by means of an electric drive motor 11 in the described embodiment.

[0056] In another embodiment it is also possible to use other drives, in particular hydraulic drives and/or drives including transmission devices for the movement of the comminuting rotor 14. At its periphery the comminuting rotor 14 has a plurality of comminuting tools 15 which co-operate with a counterpart blade arrangement 16 disposed stationarily relative to the machine housing 10 during the comminuting operation, for comminuting the comminution material. In the comminuting apparatus shown in Figure la the comminution material is introduced from above into the opening of a hopper 19 connected to the housing and then drops into the comminuting chamber which is delimited downwardly by the bottom and the comminuting rotor 14. In terms of understanding the present invention the comminuting rotor delimits that comminuting chamber but is part thereof. In the illustrated embodiment the comminuting apparatus can be arranged on a frame above a conveyor belt so that the comminuted material drops on to the conveyor belt which is disposed beneath the comminuting rotor, and can be received and transported away by same.

[0057] To describe a configuration according to the invention of the comminuting apparatus shown by way of example in FIG. 1a reference is now made to FIG. 1b which in relation to the invention shows functional regions of a comminuting apparatus according to the invention. In the described embodiment the comminution material introduced into the comminuting chamber is comminuted by the rotor 14. The comminuted material or ground material then here falls on to a conveyor belt 20 which is arranged beneath the rotor 14 and with which the ground material is transported for example into a storage arrangement. For detecting the state of the ground material sensors, in particular optical sensors, can be provided in the region directly beneath the rotor in order to detect the actual value of the temperature and the moisture content of the ground material. For that purpose, the arrangement has the temperature sensor 30 and the moisture content sensor 31. FIG. 1b diagrammatically also shows a mass sensor 32 adapted to detect the mass flow of the ground material.

[0058] In order to cool the material to be comminuted or the ground material the comminuting apparatus 1 according to the invention has a cooling device which includes a plurality of structural components, which are different depending on the respective design configuration involved, for constituting the coolant device. FIG. 1b simultaneously functionally shows two variants of a cooling device relating to the configuration of the comminuting apparatus according to the invention, in which respect the elements disposed in the rectangle identified by reference 46 are initially insignificant for an embodiment. According to the invention cooling is effected here with a liquid water-based coolant, wherein the coolant in the described embodiments has a water content of 100%. In that respect cooling is effected by the use of pure water so that the cooling device can be connected directly by means of a conventional water connection 40 to a conventional water supply mains. In the first-described embodiment the feed flow of the coolant can be set by way of a two-way valve 42 and the volume flow of the coolant or the water can be detected by way of a volume flow measuring device 43. The coolant is passed by way of a conduit 41 to nozzles 48b arranged in the region of the rotor of a nozzle device 48, by way of which the coolant depending on the respective embodiment is introduced for example directly on to the rotor and/or into the comminuting chamber. To ensure that the coolant is introduced as homogeneously and uniformly as possible the cooling nozzle device 48 can include nozzles 48b arranged in spaced relationship in the longitudinal direction relative to the rotor in order to introduce the coolant over the entire working width of the rotor corresponding to its axial working length. To enhance the interaction of the coolant with the material in the comminuting chamber, that is to say the material to be comminuted and the partially or completely comminuted material, it can be provided that specific nozzles, here water nozzles, are used, which are adapted to create a fine water mist, wherein individual droplets are of a diameter of <100 μm or even <50 μm depending on the respective design structure.

[0059] In particular in such cases in which the water pressure of the water supply is not sufficient to feed the nozzle device with cooling water at the respectively required pressure it can be provided that further structural elements are incorporated into the cooling device, which are shown in the broken-line region 46 in FIG. 1b. This concerns a water tank 44 which is connected to the water supply by means of the water connection 40 and has a filling level monitoring means, to which at the outlet side there is connected a pump 45 which here is further adapted for volume flow measurement of the volume flow delivered by the pump in the direction to the nozzles 48b.

[0060] Control of the cooling device is effected in the described embodiment by means of a control device 55 which can be arranged together with the control device 56 of the comminuting rotor, that is to say the control for controlling the rotor drive, in a control cabinet 50. In that respect the control devices 55, 56 can be coupled or can be combined together in a central control in order to couple the comminuting process to the cooling process or to use operating parameters of the comminuting process, for example information about the drive power which depends on the material flow of the material to be comminuted through the rotor, for open-loop or closed-loop control of the cooling device. In a similar manner cooling operating parameters can be forwarded by the control of the cooling device to the control of the rotor or the rotor drive in order to adapt the comminuting action to the operation of the cooling device.

[0061] The conduits shown in FIG. 1b of the valve device 42 and the volume flow measuring device 43, the water tank 44, the pump 45 and the sensors 30, 31, 32 to the control 55 of the cooling device can be adapted depending on the respective application both for the communication of control signals and also data signals, under some circumstances also bidirectionally.

[0062] FIG. 2 shows the view of FIG. 1b with a higher degree of abstraction in the manner of a flow chart, wherein relevant operating parameters and measurement variables are specified for the embodiment of the method according to the invention and the apparatus according to the invention. The material to be comminuted which is introduced into the comminuting chamber of the machine housing 10 has a moisture content FI. It is comminuted by means of the comminuting rotor 14, wherein the drive motor 11 of the comminuting rotor uses an electric drive power P. The material comminuted by the rotor (ground material) drops on to the conveyor belt 20 at which or in the region of which respective sensor devices are disposed for detecting the temperature TO of the comminuted material (output material), the moisture content FO of the output material, the volume flow VO of the output material and/or the mass flow MO of the output material. The ground material which is transported away from the comminuting apparatus can be passed for example into a store 90. The feed of coolant is effected with a volume flow VS, wherein in this embodiment the discharge of coolant by way of a nozzle device 48 is controlled by means of the valve device 42.

[0063] The process control is not specified in the flow chart in FIG. 2, by definition. The described cooling of the material to be comminuted or of partially comminuted material in the comminuting chamber is effected to avoid elevated temperatures of the comminution material. For that purpose it can be provided that the apparatus according to the invention is designed and adapted to carry out a method in which the comminution material, that is to say the material to be comminuted, the partially comminuted material and/or the comminuted material, is cooled by means of a liquid water-based coolant, wherein an introduction rate, for example a volume flow or a mass flow of the coolant, into the comminuting process or the comminuting chamber, is adapted to an operating parameter of the comminuting apparatus, that is dependent on the quantitative throughput of the comminution material, like a volume throughput of the comminution material, a mass throughput of the comminution material and/or a drive power output of the comminuting rotor drive. According to the invention that adaptation is effected in such a way that more than 60% of the cooling capacity introduced into the comminution material is provided by the latent heat of the liquid coolant. Depending on the specific configuration of the method according to the invention the percentage proportion of the latent heat in relation to the total cooling capacity can also be set to be greater, for example more than 70% or more than 80% of the cooling capacity.

[0064] In then event of complete conversion of the heat capacity of the material dQ.sub.MATERIAL/dt into the cooling capacity of the coolant with complete transition of the coolant into the vaporous phase the foregoing formula for the mass introduction rate dm.sub.WATER/dt=(dQ.sub.MATERIAL/dt)* 1/q.sub.WATER or the volume introduction rate VS=dV.sub.WATER/dt=(dm.sub.WATER/dt)*(1/q.sub.WATER), wherein q.sub.WATER specifies the density of the coolant, here water. According to the invention adjustment is effected in dependence on the respective configuration involved by way of open-loop control or closed-loop control of the coolant introduction rate VS in the described fashion, wherein the introduction rate is reduced in accordance with the specified instruction if less than 60% of the cooling capacity introduced into the comminution material is provided by the latent heat of the coolant. The fact of the threshold being exceeded in that way can be detected for example by the moisture content FO of the comminuted material displaying a corresponding increased value, equivalent to the fact that the cooling capacity is provided to a lesser percentage by the latent heat of the coolant. Depending on the respective embodiment involved it can for example also be provided that suitable closed-loop or open-loop control is implemented in such a way that adaptation of the coolant introduction rate to the quantitative throughput of the comminution material into the comminuting process is carried out in such a way that more than 70%, more than 80%, in particular more than 90% of the coolant introduced transitions into the vaporous phase during the cooling process. If that percentage is not reached, which can be detected for example by measuring an increased moisture content in the comminuted material, it is possible in accordance with the invention in this embodiment to reduce the coolant introduction rate VS.

[0065] It can be provided that, in the method according to the invention or the comminuting apparatus according to the invention, cooling of the comminution material is subjected to closed-loop control. For example, in an embodiment a temperature of the comminuted material can be measured and subjected to closed-loop control to a predetermined set point temperature of the comminuted material with a setting variable establishing the coolant introduction rate, insofar as the temperature of the comminuted material represents the closed-loop control variable. FIG. 3 shows a corresponding closed-loop control circuit 60 for carrying out an embodiment of the invention for such a closed-loop control, wherein a temperature T.sub.SET POINT which is predetermined and generally dependent on the respective comminution material is implemented as the reference variable. In the described embodiment the closed-loop controller 61 is in the form of a PI or PID closed-loop controller. It outputs an actuating signal u(t) for actuation of a setting member 62 which sets the setting variable volume flow VS of the coolant. In that respect the valve device 42 in FIG. 2 corresponds to the setting member 62. The setting variable y(t) corresponds to that volume flow VS of the coolant. The closed-loop control section 63 corresponds to the installation part of the comminuting apparatus according to the invention between the location of the setting member 62 and the measuring member 64, that is to say in the FIG. 2 embodiment the valve device 42, and the temperature sensor for detecting the temperature TO of the comminuted material. An appropriate configuration of the closed-loop control variable also takes account of the action of disturbance variables zi(t), for example the heat stored in the machine components and/or the ambient temperature as well as further external effects which have an effect on the comminuting process and/or the cooling process. The resulting temperature TO of the comminuted material is detected by way of the measuring member 64 and fed back for comparison with the reference variable w(t) (set point temperature) and for ascertaining the control deviation e(t), here ΔT=T.sub.SET POINT−TO.

[0066] In a further embodiment it can also be provided in relation to the method of FIG. 3 that a predetermined moisture content FO-set point is to be predetermined as the reference variable of the closed-loop control, wherein the closed-loop control circuit can be designed corresponding to the circuit shown in FIG. 3, that is to say the closed-loop control circuit is implemented in the form of a one-point control for control of a predetermined moisture content of the output material, wherein again the introduction rate or the volume flow VS of the coolant functions as the setting variable and the moisture content of the output material represents the closed-loop control variable.

[0067] FIG. 4 shows a further embodiment for implementation of the method according to the invention, in which the closed-loop control circuit 60b implements two-point control, in which the valve device represents a setting member 63b which is in the form of a two/two-way valve. In that respect the setting member 63b sets the volume flow of the coolant in such a way that the temperature TO of the output material remains between a temperature upper limit T.sub.SET POINT_H and a temperature lower limit T.sub.SET POINT_L. While the controllers 61a, b and the setting members 62a, b of the method in FIGS. 3 and 4 differ the control section 63 is identical insofar as there are no further installation-specific modifications.

[0068] FIG. 5 shows a further closed-loop control circuit for implementing the method according to the invention, in which a predetermined period of time t0 is applied to the controller 61c as a further process variable, a maximum allowed temperature of the comminuted material T.sub.SET POINT_H is predetermined as a reference variable and the actual temperature TO is again detected by way of the measuring member 64. Closed-loop control with the actual temperature TO of the comminuted material as the closed-loop control variable is effected here by a suitable configuration of the controller 61c in such a way that the setting member 62c which is again in the form of a two/two-way valve sets the volume flow of the coolant in such a way that, upon attainment of the temperature upper limit T.sub.SET POINT_H over a period of time tO coolant is fed to the comminuting process and thus heating capacity is removed.

[0069] FIG. 6 shows a further closed-loop control circuit for implementation of the method according to the invention, in which a maximum temperature of the comminuted material T.sub.SET POINT_H is used as the reference variable and the temperature TO of comminuted material is used as the closed-loop control variable. Unlike the method with the closed-loop control circuit of FIG. 3 the control circuit has a controller 65 which can involve both the closed-loop control deviation ΔT and also operating parameters or measurement variables of the apparatus as input variables, like for example the drive power P, the mass flow MO and the volume flow VO of the comminuted material, the moisture content FI of the material to be comminuted and/or the moisture content FO of the comminuted material. Therefrom the closed-loop controller 65 ascertains an actuating signal u(t) with which the setting member 62, for example a valve device for setting a coolant flow, is actuated. In that way for example in the event of control of the temperature TO of the ground material it is possible to intervene by the control device 65 if the moisture content FO of the ground material attains inadmissible values. For that purpose, the controller 65 can be adapted to deliver an output signal u(t) which serves as a control signal for the setting member in order to actuate same to reduce the coolant introduction rate. For example, a signal for displaying the direction of rotation of the comminuting rotor can serve as further input variables of the controller 65. In that way the closed-loop controller 65 can be adapted to reduce the coolant introduction rate or to set it to zero if that display signal displays reverse rotation of the comminuting means.

LIST OF REFERENCES

[0070] 1 comminuting apparatus
10 machine housing, machine frame
11 drive motor
14 comminuting rotor, rotor
15 comminuting tools
16 counterpart blade
17 comminuting chamber
17a bottom of comminuting chamber
18 feed device
19 hopper
20 conveyor belt
30 temperature sensor
31 moisture content sensor, moisture sensor
32 mass sensor
40 water connection
41 water conduit
42 valve, valve device
43 water-volume flow measuring device
44 water tank with filling level monitoring
45 water pump, coolant pump
48 nozzle device
48a water nozzle, nozzle
50 control cabinet
55 control device of the cooling device
56 control device of the comminuting rotor
60 control circuit
61 closed-loop controller
62 setting member
63 closed-loop control section
64 measuring member
80 comminuted material/ground material
90 mounting
TO temperature of the comminuted material (output)
VS introduction rate, volume flow of the coolant
FI moisture content of the material to be comminuted (input material)
P electric drive power of the rotor drive
FO moisture content of the output material
VO volume flow of the output material
MO mass flow of the output material
w(t) reference variable
T.sub.SET POINT set point temperature
X(t) closed-loop control variable
u(t) actuating signal of the setting member
y(t) setting variable
z(t) disturbance variable
e(t) closed-loop control deviation

K710622US