Shredding device with cooling device and method for its operation

Description

[0001] The invention relates to a comminution device in which a comminution rotor is mounted on a machine frame and has a plurality of comminution tools on its circumference, wherein the comminution rotor is arranged in a comminution chamber receiving comminution material and is designed to comminute the material located in the comminution chamber, further comprising a coolant device which is designed to introduce a liquid, water-based coolant into the comminution chamber and comprising a control device for controlling the coolant device to adjust an introduction rate of the coolant into the comminution chamber.

[0002] Such comminution devices are well known in the field, particularly in the comminution of plastic materials, for example for the utilization of production residues or the recycling of plastic materials. Particularly in the processing of plastics, but under certain circumstances also for other specific materials, they are necessary during the comminution process to prevent the process heat acting on the material to be comminuted during the comminution process from resulting in an excessively high temperature of the material. This could potentially complicate the comminution process itself, which requires cutting, breaking, and / or tearing of the material, or even cause an undesirable phase transition in the comminution material, which could complicate or even prevent subsequent processing of the ground material.

[0003] Such a conventional comminution device, which is designed to cool the material to be comminuted during the comminution process, is described, for example, in the published patent application EP 1 364 713 A2. It teaches the use of a gas such as compressed air and / or a liquid such as cold water as the cooling medium in order to dissipate the generated process heat and thus prevent the material being comminuted from reaching temperatures that are unsuitable for the comminution process. Disposal of the used, heated cooling medium is conventionally carried out by removing the comminuted material or by means of a separate device which, for example, conducts the cooling medium through an external heat exchanger and makes it available for reuse in a closed circuit.

[0004] US 4,098,463 describes a generic comminution device which describes a control of the introduction rate of the cooling medium.

[0005] It has been found that the described prior-art comminution devices often do not provide sufficient removal of process heat, particularly with thermally sensitive materials, to prevent an unwanted change in state or even ignition of the material during the comminution process. Furthermore, the disposal or recycling of the used, heated cooling medium in prior-art devices involves increased device-side expenditure and increased maintenance effort for the comminution device. Furthermore, particularly with the conventional water cooling described, the moisture content of the comminuted material can increase to such an extent that subsequent processing of the ground material is difficult or leads to inferior products.

[0006] The present invention is based on the object of at least partially remedying the described disadvantages of conventional comminution devices according to the prior art. This object is achieved by a comminution device having the features of claim 1. The comminution device according to the invention has a comminution rotor which is mounted on a machine frame and comprises a plurality of comminution tools on its circumference, wherein the comminution rotor is arranged in a comminution chamber receiving comminution material and is designed to comminute the material located in the comminution chamber, wherein, in addition, a coolant device is provided which is designed to introduce a liquid coolant having a water content of at least 80% into the comminution chamber.Furthermore, the comminution device according to the invention comprises a control device for controlling the coolant device to adjust an introduction rate of the coolant into the comminution chamber. Furthermore, the control device is configured and designed to adapt an introduction rate of the liquid, water-based coolant into the comminution process or the comminution chamber in which the comminution process takes place to an operating parameter of the device dependent on the mass 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, in particular a drive motor of the rotor, such that more than 60% of the cooling power introduced into the comminution material or the comminution chamber is provided by the latent heat of the liquid, water-based coolant.The specified mass flow rate of the material to be comminuted, to which the coolant introduction rate is adjusted, can be the mass flow rate of the material to be comminuted or the mass flow rate of the comminuted material (ground material). The comminution device according to the invention is characterized in that the comminution device comprises at least one moisture sensor for detecting a moisture content of the comminuted material, wherein the control device is designed to regulate to a predetermined target moisture content or a predetermined target moisture content range of the comminuted material using a control variable that determines the coolant introduction rate.

[0007] The comminution device according to the invention is based on the fundamental idea of ​​designing a coolant device with appropriate control in such a way that a liquid, water-based coolant is introduced into the comminution chamber in which the comminution process takes place and process heat is generated by the comminution process, in such a way that the cooling capacity is provided essentially, in particular to a predominant extent, by the latent heat of the water-based coolant, so that with comparatively little coolant input, an effective process heat removal can be provided, without resulting in increased temperatures of the comminuted material, which could be detrimental to further processing of the comminuted material. Since the introduction rate of the coolant is adapted to the mass throughput of the comminution material that is processed in the comminution process, aa predetermined moisture content threshold of the comminuted material (ground material), which makes further processing of the comminuted material more difficult, can be avoided or, under certain circumstances, the moisture content of the comminuted material can be set lower than the moisture content of the material fed to the comminution rotor. In this respect, the comminution device according to the invention can be designed and controlled such that at any time sufficient coolant is fed into the comminution process to provide optimum cooling performance and, at the same time, the cooling The comminution device according to the invention can be designed and controlled such that at any time sufficient coolant is fed into the comminution process to provide optimum cooling performance and, at the same time, the coolant is essentially completely expelled from the material during comminution by transitioning into the gaseous phase through evaporation or vaporization.By controlling the cooling device as described, an operating situation can be avoided in which too much coolant is introduced into the comminution chamber, with the result that an increased cooling proportion is provided by the coolant in the liquid state and thus a lower conversion of coolant into the vaporous phase occurs.

[0008] With the comminution device designed according to the invention, in one embodiment, thermally sensitive materials in particular, for example plastic sheets, can be comminuted to a small grain size, for example < 12 mm, in a single stage, without the need for subsequent comminution, for example in cutting mills. The comminution device according to the invention can ensure a high level of process reliability; moreover, the efficiency of the comminution device according to the invention can be improved compared to conventional comminution devices, which enables an increase in material throughput with the same rotor drive power. The effective cooling of the material to be comminuted provided by the comminution device according to the invention can lead to a reduction in wear of the comminution tools on the rotor orof counterblade(s) attached to the machine frame due to the reduced friction and thermal stress on the components. A further significant advantage of the comminution device according to the invention over prior art comminution devices can be the elimination of additional units for disposing of the used, heated cooling medium. Furthermore, the amount of cooling medium can be significantly reduced with the comminution device designed according to the invention.

[0009] The term "liquid water-based coolant" here refers to a coolant that essentially consists of water with a weight fraction of more than 80%, especially more than 90%. In particular, the coolant can also consist entirely of water without any additives. However, it is also within the scope of the invention to use a water-based coolant with additives. For example, a soap additive can be added to the coolant to simultaneously create a washing process on the material.

[0010] The statement "cooling capacity introduced into the comminution chamber" or "cooling capacity introduced into the comminution material" may refer to the cooling capacity provided by the coolant, which is absorbed by the material to be comminuted or the comminutioned material, and thus leads to a reduction in the temperature of the material.

[0011] Further advantageous features and developments of the invention are specified in the following general description, the figures, the description of the figures and the dependent claims.

[0012] The cooling device or coolant device of the comminution device according to the invention can expediently comprise a coolant connection for connection to a coolant network, such as a water supply network or a coolant reservoir. Provided the pressure in the supply network is sufficient, the comminution device according to the invention can comprise a valve device for controlling the introduction rate of the liquid, water-based coolant. In embodiments of the comminution device according to the invention in which it comprises a coolant reservoir, a coolant pump can be included to adjust the specified introduction rate of the coolant, possibly in conjunction with a valve device, e.g., by determining the mass flow or volume flow of the coolant in the comminution process.

[0013] The term "shredding chamber" can include an introduction chamber for receiving the material to be shredded, including the installation space of the rotor. It can also be provided that this shredding chamber can be modified, for example, by a feed device such as a drivable slide of a feed device, in particular for moving the material to be shredded toward the shredding rotor. According to the invention, it can also be provided that the material to be shredded can be introduced into the shredding chamber via a feed hopper, whereby a feed device can also be included in this embodiment.

[0014] It should be noted that the introduction of the liquid, water-based coolant into the comminution process can be carried out continuously or discontinuously, whereby the "coolant introduction rate" or "mass throughput of the comminution material" refers to a respective specified period of time. This period can, for example, be in the range of seconds or even minutes.

[0015] To ensure that the comminuted material does not exceed a predetermined moisture content or lies within a predetermined moisture content range, the comminution device according to the invention can be provided with the control device configured and designed to adapt the coolant introduction rate to the mass flow rate of the comminution material in the comminution process in such a way that more than 70% or more than 80%, in particular more than 90% of the introduced coolant changes from the liquid to the vapor phase during cooling of the comminution material or the comminuted material. Accordingly, the control device can be configured and designed to control the introduction rate in such a way that a predetermined moisture content of the comminution material is not exceeded or the moisture content of the comminution material lies within a predetermined moisture content range.This upper limit can, for example, correspond to a processing moisture content that indicates the maximum possible moisture content in the comminuted material, such as plastic granules, at which the quality of the resulting molded parts or semi-finished products is still assured. A typically permissible water content for processing plastics such as PE, PB, PA, and PET can be approximately 0.02 to 0.1 wt.%, which can be maintained for the comminuted material using the comminution device according to the invention.

[0016] According to the invention, the comminution device comprises at least one moisture sensor for detecting a moisture content of the comminution material, wherein the control device is configured to control or regulate the comminution material to a predetermined target moisture content or a predetermined target moisture content range using a control variable that determines the coolant introduction rate. Such a control variable can, for example, comprise a control signal for a valve device and / or a coolant pump of the cooling device.

[0017] In order to prevent a predetermined temperature of the comminuted material from being exceeded during the comminution process, it can be expediently provided that the comminution device according to the invention comprises at least one temperature sensor for detecting a temperature of the comminuted or partially comminuted material in the comminution chamber and / or for detecting a temperature of the comminuted material outside the comminution chamber, wherein the control device is designed and configured to control or regulate the comminuted material to a predetermined target temperature or a predetermined target temperature range using a control variable that determines the introduction rate of the coolant. This control variable can be identical to the control variable specified above for controlling the moisture content of the comminuted material.It is within the scope of the invention that the at least one temperature sensor for detecting the temperature of the comminuted material in the comminution chamber can be designed and arranged to detect the temperature of the comminuted material in the region of the comminution process, i.e. in a region of the comminution device in which the comminution process takes place, for example in the region of the rotor, possibly in the region of counter knives arranged stationary to the machine frame, since the comminution of the material to be comminuted predominantly takes place in these regions. For example, particularly in comminution devices in which a screening device surrounds the comminution rotor on part of its circumference, the at least one temperature sensor can be arranged and designed to detect the temperature of the material to be comminuted still in the comminution process between the screening device and the rotor, i.e. within the comminution chamber.It is possible that at least one temperature sensor is arranged and designed to detect the temperature of the shredded material that has moved out of the effective range of the shredding rotor and thus out of the shredding chamber, for example, after the shredding process, has been guided or fallen downwards onto a conveyor belt arranged below the rotor.

[0018] Since the greatest process waste heat is generally generated in the area of ​​or at a short radial distance from the comminution tools of the rotor, it can be expediently provided that the comminution device according to the invention comprises at least one temperature sensor for detecting a temperature on the rotor, in particular a temperature in the area of ​​one or more comminution tools, wherein the control device is designed to regulate to a predetermined target temperature or a target temperature range of the rotor with a manipulated variable that determines the introduction rate of the coolant.

[0019] It can be provided that when controlling the coolant introduction rate into the comminution process or the comminution chamber, not just one of the above-mentioned input variables is taken into account, but several, in particular the volumetric throughput of the material to be comminuted, the mass throughput of the material to be comminuted, a temperature of the comminuted material, a temperature of the material to be comminuted, a temperature at the rotor, a moisture content of the comminuted material and / or a moisture content of the material to be comminuted. In particular, it can be provided that the control includes at least the temperature and the moisture content of the comminuted material as controlled variables and is designed as a multi-variable control, wherein the respective setpoint or setpoint range of the comminuted material is controlled with a manipulated variable that determines the coolant introduction rate.

[0020] In order to provide a manipulated variable for the control, the cooling device of the comminution device according to the invention can comprise a connection device for connection to a coolant line network and / or for connection to a coolant reservoir and a coolant nozzle device comprising at least one coolant nozzle for introducing coolant into the comminution process or the comminution chamber, wherein the control device for controlling the introduction rate of the coolant into the comminution chamber can be designed to control or adjust at least one flow valve of the coolant and / or at least one coolant pump. Depending on the embodiment, the manipulated variable can be, for example, a control signal for a coolant flow valve or a coolant pump. In the control, the manipulated variable can, for example, be designed to carry out a two-point control, ie in this case a flow valve or a valve device, opened or closed orA coolant pump can be switched on or off. However, it can also be provided that the manipulated variable is continuously changed, for example by providing corresponding control signals from the control device to continuously adjust the flow through the valve or the valve device or the pumping capacity of the coolant pump. A flow rate sensor for detecting the coolant introduction rate can expediently be provided in the comminution device according to the invention.

[0021] In order to convert as high a proportion as possible of the coolant introduced into the comminution process or the comminution chamber into the gaseous phase, it can be provided that the coolant is introduced into the comminution process or the comminution chamber in a finely distributed manner, in particular in the form of a uniform atomization, in order to achieve the lowest possible temperature of the comminuted material and the lowest possible degree of moisture in the comminuted material.

[0022] In order to ensure uniform introduction of the coolant, it can expediently be provided that the coolant nozzle device has a plurality of nozzles arranged on the machine frame of the comminution machine at a distance from the longitudinal axis of the rotor. These nozzles can be arranged above the rotor in the installed position, so that the introduced liquid coolant falls due to its weight towards the rotor or into a section in the region of the rotor in which the respective comminution process essentially takes place. It can also be provided that the coolant nozzle device has a plurality of nozzles arranged on the circumference of the rotor at a distance from the longitudinal axis of the same for introducing the water-based coolant, wherein the nozzles can be aligned in the radial direction to the rotor. In both variants, a nozzle device that continuously discharges coolant in the longitudinal direction of the rotor can also be used.

[0023] The coolant nozzle device can be configured to apply the coolant to the rotor and / or to the material to be shredded. For example, one or more nozzles can be directed toward the rotor and / or one or more nozzles can be directed toward the material to be shredded in the region of the rotor. The term "directed" refers to an orientation for discharging the liquid coolant toward the rotor or the material to be shredded or partially shredded.

[0024] To increase the phase transformation of the coolant by providing a large surface area for the introduced coolant, it can be expediently provided that the coolant nozzle device is designed and configured to introduce the water-containing coolant in the form of a water mist into the comminution process, in particular onto the rotor and / or the material to be comminuted in the region of the rotor, wherein the water mist droplets have a diameter of < 100 µm, in particular < 50 µm. In particular, corresponding nozzles for introducing the liquid coolant can be designed to atomize the coolant, resulting in the specified droplet size.

[0025] In order to prevent the humidity level of the air in the region of the comminution device according to the invention from exceeding a predetermined threshold value during operation, it can be expediently provided that the comminution device has a suction device designed to at least partially suction away the coolant vapor, in particular water vapor, that develops during the cooling of the comminution material. Such a measure can be particularly useful in a comminution device according to the invention that generates increased process heat due to the material to be comminuted, which, as described, is dissipated in the device according to the invention essentially through the phase transition of the coolant.

[0026] In order to optimize the control behavior during operation of the comminution device according to the invention, the device can have at least one moisture sensor for detecting a degree of moisture of the material to be comminuted, in particular outside the comminution chamber, wherein the control device can be designed to regulate the introduction rate for the coolant introduced into the comminution process as a further control variable depending on this.

[0027] In order to provide uniform cooling within the comminution process over the entire effective width (axial effective length) of the rotor, it can expediently be provided that the comminution material is fed uniformly to the rotor, for example by means of a feed device acting over the effective width of the rotor, and the coolant device is designed to provide an introduction of the coolant, in particular a uniform introduction over the effective width of the rotor, over the comminution material arranged over the entire effective width of the rotor.

[0028] The above-mentioned object is further achieved by a method for cooling comminution material and / or comminuted material in a comminution device which is designed to carry out a comminution process in which comminution material located in a comminution chamber of the comminution device is comminuted by means of comminution tools attached to the circumference of a comminution rotor, wherein during the comminution process a liquid water-based coolant comprising at least 80% water is introduced into the comminution chamber or the comminution process taking place in the comminution chamber.Furthermore, the coolant introduction rate into the comminution process is adapted to an operating parameter of the device dependent on the mass flow rate of the comminution material, in particular a volume flow rate of the comminution material, a mass flow rate of the comminution material in the device, and / or a drive power of the rotor drive, such that more than 60% of the cooling power introduced into the comminution material is provided by the latent heat of the water-based coolant. The method according to the invention is characterized in that a moisture content of the comminution material is measured and regulated to a predetermined target moisture content or a target moisture content range of the comminution material using a control variable that determines the coolant introduction rate.

[0029] As already explained above, the introduction of the water-containing coolant into the comminution process or the comminution chamber can be carried out continuously or discontinuously; according to the invention, in both cases this introduction rate is adapted to an operating parameter dependent on the mass throughput of the comminution material, ie to the quantity of the comminution material.

[0030] Depending on the embodiment, the adjustment of the coolant introduction rate can be designed such that more than 70%, in particular more than 75%, preferably more than 80% of the cooling power introduced into the material to be comminuted or into the comminution chamber is provided by the latent heat of the coolant introduced.

[0031] In particular, in order to avoid a moisture level of the comminuted material that makes subsequent processing of the comminuted material more difficult, it can be expediently provided that the adjustment of the introduction rate of the coolant to the mass throughput of the comminuted material in the comminution process is carried out in such a way that more than 80%, in particular more than 90% of the introduced coolant changes from the liquid to the vapor phase when cooling the comminuted material or the comminuted material.

[0032] To explain the adjustment of the feed rate to the mass flow rate of the material to be shredded by the shredding device according to the invention, it is assumed below that 100% of the introduced coolant changes from the liquid to the vapor phase during cooling of the material to be shredded or the shredded material. Furthermore, it is assumed that the temperature of the material to be shredded, T input material, introduced into the shredding chamber is identical to the temperature of the shredded material, i.e., after the shredding process has been carried out under the influence of the described cooling. During the shredding of the material to be shredded, the temperature of the shredded material increases due to the process heat. without cooling to T Output-Material . Therefore, the cooling capacity must be provided by the coolant: Q ˙ Material = m ˙ Material ∗ c p Material ∗ T Output − Material − T Input − Material where dQ material / dt is the heat input into the shredded material, dm material / dt is the mass flow rate of the shredded material, and CP material is the specific heat of the shredded material. In the ideal case considered, 100% of the heat input into the shredded material during the shredding process is compensated using the latent heat of the coolant during its transition to the vapor phase. For the following analysis, pure water is supplied as the coolant at a temperature Ta, resulting in a specific heat quantity for this coolant as follows: q Wasser = 4 , 18 kJ / kg * K * 100 − T a K + 2246 kJ / kgV .

[0033] For an exemplary water introduction temperature Ta of 15°, the specific heat quantity is q Wasser = 2602 , 15 kJ / kg .

[0034] Therefore, when using pure water as a coolant, cooling due to the occurrence of latent heat accounts for more than 86% in the example described.

[0035] The above considerations lead to the equation dm Wasser / dt * q Wasser = dQ Material / dt , whereby the coolant introduction rate can be determined for the ideal case considered here, in which it is assumed that the entire coolant introduced into the comminution process passes into the vapor phase.

[0036] It is evident that the rate at which the coolant is introduced into the comminution process depends on the physical properties of the respective material to be comminuted, in particular the specific heat capacity, a transition temperature such as a melting temperature or a self-ignition temperature, and must therefore be adapted to the respective material.

[0037] In the method according to the invention, a temperature of the comminuted material can be measured and regulated to a predetermined target temperature or a target temperature range of the comminuted material using a control variable that determines the coolant introduction rate. Such a target temperature can, for example, be below a melting temperature, which, depending on the application, must be avoided during the comminution process in order not to impede subsequent processing, for example. For example, an actual temperature of the comminuted material can be measured, and if a predetermined temperature threshold is exceeded, the coolant introduction rate can be increased, preferably being regulated to a predetermined target temperature using a control variable that determines the coolant introduction rate, for example a signal for operating a coolant pump and / or a coolant valve.When carrying out the method according to the invention, the introduction rate of the coolant is expediently recorded, for example by measuring the mass or volume flow rate of the coolant, from which the introduction rate can be determined, in particular calculated.

[0038] It can be provided that a temperature on the rotor, in particular a temperature in the area of ​​one or more comminution tools, is measured and regulated to a predetermined target temperature or a target temperature range of the rotor using a control variable that determines the coolant introduction rate. It can also be provided that both a temperature of the rotor and a temperature of the comminuted material are used as a control variable, with the introduction rate as the control variable. In order to avoid a moisture level that is not conducive to further processing of the comminuted material when carrying out the method according to the invention, it is provided that a moisture level of the comminuted material is measured and regulated to a predetermined target moisture level or a target moisture range of the comminuted material using a control variable that determines the coolant introduction rate. In this case, it can also be expedient to use the moisture level of the material to be comminuted, i.e.before the shredding process, whereby this measurement is also included in the described control.

[0039] In order to provide both temperature control and moisture control of the comminuted material, the method according to the invention may incorporate both the temperature and moisture content of the comminuted material as controlled variables, thus designing the control system as a multivariable control system, and controlling the respective setpoint or setpoint range of the comminuted material with a control variable that determines the coolant introduction rate. In particular, the control system may include a decoupling controller.

[0040] In order to ensure the most homogeneous introduction of the cooling medium into the comminution chamber or the comminution process, which in most embodiments takes place in the region of the comminution rotor, it can be provided that the coolant is introduced via a plurality of locations spaced from the longitudinal axis of the rotor, at which nozzles or nozzle devices can be arranged. It can also be provided that the coolant is introduced via nozzle devices that are attached or formed directly on the rotor. In this embodiment, the rotor can therefore comprise at least one coolant supply line for guiding coolant to the nozzle devices.

[0041] For more precise control of the method according to the invention, it can be provided that a respective temperature of or in the shredded material is detected by means of a plurality of spaced-apart temperature sensors, and the control is carried out depending on the plurality of temperatures detected by the temperature sensors. Similarly, a plurality of spaced-apart moisture sensors can detect a respective moisture level in the shredded material, and the control is carried out depending on the plurality of moisture levels detected by the moisture sensors.

[0042] In order to ensure the most uniform introduction of the coolant into the comminution process, it can be provided that the coolant is applied to the rotating rotor and / or to the material to be comminuted, particularly in the area of ​​the rotor. Particularly in comminution devices in which the comminution tools arranged on the rotor cooperate with associated counterblades fixedly mounted on the machine frame, it can also be provided that coolant is introduced into the comminution chamber or the comminution process in the area of ​​the counterblades or the counterblade.

[0043] Depending on the arrangement of at least one nozzle of a nozzle device for introducing the coolant, in order to enlarge the surface of the coolant and thus to improve the cooling efficiency, it can be provided that the coolant is introduced into the comminution process in the form of a water mist, in which the water mist droplets have a diameter of < 100 µm, in particular < 50 µm.

[0044] In the method according to the invention, the introduction rate of the coolant can be set as a control variable of the control, in particular by means of control signals for a coolant valve device and / or by means of control signals for a coolant pump.

[0045] As explained above, the method and device according to the invention also have the advantage over conventional devices that the heated coolant generally does not need to be removed from the comminuted material. To avoid unacceptable humidity in the working environment of the comminution device, it can be advantageously provided that the vaporous substance, in particular water vapor, developed during the cooling of the comminution process is at least partially extracted. Such vapor can, for example, be guided outside the location of the comminution device and, in the case of pure water vapor, be released in an environmentally friendly manner.

[0046] In one embodiment, the mass flow rate or volume flow of the material to be shredded can be measured directly and incorporated into the control system according to the invention. However, it is also possible to determine the mass flow rate or mass or volume flow of the material to be shredded based on the drive power of the motor driving the shredding rotor, so that the mass flow rate of the material to be shredded can be indirectly measured by determining the drive power to adjust the coolant introduction rate.

[0047] With the explained controls in the method according to the invention for cooling comminution material and / or comminuted material, external influences on the comminution process, for example stored heat from machine components and / or the environment, which can also change during the operation of the device, can be regulated out, so that these disturbance variables mentioned as examples as well as other disturbance variables that may occur and affect the comminution process can be compensated.

[0048] To adapt the respective controller to the specific controlled system, well-known controllers can generally be used, such as PID or PI controllers. As shown, these controllers can be designed as single-point controllers, multi-point controllers, or especially two-point controllers, to reflect the specific time behavior of the controlled system.

[0049] The invention is explained below by describing some embodiments of the comminution device according to the invention or the method according to the invention with reference to the attached figures, wherein Figure 1a shows a view of a comminution device designed according to the invention, Figure 1b shows a functional principle sketch of the structure of a comminution device designed according to the invention, Figure 2 shows a flow diagram of the comminution process of the comminution device of the Figure 1a , b, Figure 3 to explain the method according to the invention for cooling shredded material a block diagram of a control loop for a one-point control when carrying out the method according to the invention, Figure 4 a block diagram of a further control loop for a two-point control for carrying out the method according to the invention, Figure 5 a block diagram of a further control loop of a time control for carrying out the method according to the invention and Figure 6 a block diagram of a control for carrying out the method according to the invention, in which in addition to the reference and controlled variables a plurality of operating parameters are used to determine the control.

[0050] Figure 1ashows a comminution device 1 designed according to the invention in a perspective view. A comminution rotor 14 is mounted on a machine housing 10 in the region of its two longitudinal ends. In the described embodiment, the rotor 14 is moved by an electric drive motor 11.

[0051] In another embodiment, other drives, in particular hydraulic drives and / or drives comprising gear devices, can also be used to move the comminution rotor 14. The comminution rotor 14 has a plurality of comminution tools 15 on its circumference, which cooperate with a counter-blade device 16, which is arranged stationary relative to the machine housing 10 during the comminution operation, for comminuting the material to be comminuted. The material to be comminuted is Figure 1aThe shredding device shown is introduced from above into the opening of a hopper 19 connected to the housing and then falls into the shredding chamber delimited at the bottom by the floor and the shredding rotor 14. Within the understanding of the present invention, the shredding rotor delimits this shredding chamber, but is part of it. In the illustrated embodiment, the shredding device can be arranged on a frame above a conveyor belt, so that the shredded material falls onto the conveyor belt arranged below the shredding rotor, can be picked up by it, and transported away.

[0052] To describe an inventive design of the Figure 1a The shredding device shown as an example is Figure 1bwhich, with reference to the invention, shows functional areas of a comminution device designed according to the invention. In the described embodiment, the comminution material introduced into the comminution chamber is comminuted by the rotor 14. The comminuted material or ground material then falls onto a conveyor belt 20 arranged below the rotor 14, with which the ground material is transported, for example, to a storage facility. To detect the condition of the ground material, sensors, in particular optical sensors, can be provided in the area directly below the rotor in order to detect the actual value of the temperature and the moisture level of the ground material. For this purpose, the temperature sensor 30 and the moisture level sensor 31 are provided. Symbolically, Figure 1b In addition, a mass sensor 32 is provided which is designed to detect the mass flow of the ground material.

[0053] In order to cool the material to be comminuted or the material to be ground, the comminution device 1 according to the invention has a cooling device which comprises several components for the design of the cooling device, depending on the embodiment. Figure 1bTwo variants of a coolant device for designing the comminution device according to the invention are shown functionally at the same time, wherein the elements located in the rectangle marked with the reference numeral 46 are initially irrelevant for one embodiment. According to the invention, cooling is carried out here with a liquid, water-based coolant, wherein the coolant in the described embodiments has a water content of 100%. In this respect, cooling is carried out using pure water, so that the coolant device can be connected directly to a conventional water supply network via a standard water connection 40. In the first-described embodiment, the coolant inflow can be adjusted via a two-way valve 42 and the volume flow of the coolant or water can be measured via a volume flow measuring device 43.The coolant is guided via a line 41 to nozzles 48b of a nozzle device 48 arranged in the region of the rotor, via which nozzle device the coolant is introduced, for example, directly onto the rotor and / or into the comminution chamber, depending on the embodiment. In order to ensure the most homogeneous and uniform introduction of the coolant, the coolant nozzle device 48 can comprise nozzles 48b arranged at a distance from the rotor in the longitudinal direction in order to introduce the coolant over the entire effective width of the rotor in accordance with its axial effective length. In order to improve the interaction of the coolant with the material in the comminution chamber, ie the material to be comminuted and the partially or completelyIn order to optimise the quality of the material completely shredded, it can be provided to use specific nozzles, in this case water nozzles, which are designed to produce a fine water mist, with individual droplets having a diameter of < 100 µm or even < 50 µm, depending on the design.

[0054] Particularly in cases where the water pressure of the water supply is not sufficient to supply the nozzle device with the required pressure of cooling water, it may be provided to integrate further components into the coolant device, which are shown in the dashed area 46 of the Fig. 1b This concerns a water tank 44 connected to the water supply via the water connection 40, with level monitoring, to which a pump 45 is connected on the output side, which pump is further designed to measure the volume flow conveyed by the pump in the direction of the nozzles 48b.

[0055] In the described embodiment, the coolant device is controlled by means of a control device 55, which can be arranged in a control cabinet 50 together with the control device 56 of the comminution rotor, ie the control for controlling the rotor drive.

[0056] The control devices 55, 56 can be coupled or combined in a central control system in order to couple the comminution process with the cooling process or to use operating parameters of the comminution process, for example, information about the drive power, which depends on the material flow of the material to be comminuted through the rotor, for the control or regulation of the coolant device. Similarly, cooling operating parameters can be passed from the control system of the coolant device to the control system of the rotor or rotor drive in order to adapt the comminution to the operation of the coolant device.

[0057] The Figure 1b The lines shown for the valve device 42, 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 coolant device can, depending on the application, be designed to transmit both control signals and data signals, possibly also bidirectionally.

[0058] Figure 2 shows the representation of the Figure 1bwith a higher degree of abstraction in the manner of a flow chart, wherein operating parameters or measured variables relevant to the embodiment of the method according to the invention or the device according to the invention are specified. The material to be shredded, which is introduced into the shredding chamber of the machine housing 10, has a moisture content FI. This is shredded by means of the shredding rotor 14, wherein the drive motor 11 of the shredding rotor applies an electrical drive power P. The material shredded by the rotor (ground material) falls onto the conveyor belt 20, on which or in the area of ​​which respective sensor devices are arranged for detecting the temperature TO of the shredded 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 transported away by the shredding device can, for example, be fed into a storage area 90.The coolant is supplied with a volume flow VS, wherein in this embodiment the discharge of the coolant is controlled via a nozzle device 48 by means of the valve device 42.

[0059] In the flow chart of the Figure 2By definition, process control is not specified. The described cooling of the material to be shredded or partially shredded material in the shredding chamber is carried out to avoid increased temperatures of the shredded material. For this purpose, it can be provided that the device according to the invention is designed and configured to carry out a method in which the shredded material, ie the material to be shredded, the partially shredded material and / or the shredded 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 shredding process orThe comminution chamber is adapted to an operating parameter of the comminution device that depends on the throughput of the material to be comminuted, such as a volumetric throughput of the material to be comminuted, a mass throughput of the material to be comminuted, and / or a drive power of the comminution rotor drive. According to the invention, this adaptation is carried out in such a way that more than 60% of the cooling power introduced into the material to be comminuted is provided by the latent heat of the liquid coolant. Depending on the specific embodiment of the method according to the invention, the percentage of latent heat in relation to the total cooling power can also be set higher, for example, more than 70% or more than 80% of the cooling power.

[0060] In the case of a complete conversion of the heat output of the material dQ MATERIAL / dt into the cooling capacity of the coolant with complete transition of the coolant into the vapor phase, the above formula applies for the mass introduction rate dm WATER / dt = (dQ MATERIAL / dt) *1 / q WATER or the volume introduction rate VS= dV WATER / dt = (dm WATER / dt) * (1 / ), where which indicates the density of the coolant, in this case water. According to the invention, the adjustment is carried out, depending on the design, via a control or regulation of the introduction rate VS of the coolant in the manner described, wherein the introduction rate is reduced according to the specified regulation if less than 60% of the cooling power introduced into the shredded material is provided by the latent heat of the coolant. This exceeding of the threshold can, for example, be detected by the moisture content FO of the shredded material indicating a correspondingly increased value, which means that a lower percentage of the cooling power is provided by the latent heat of the coolant. Depending on the design, it can also be provided, for example, via a corresponding control or regulation.The control is to be carried out in such a way that the coolant introduction rate is adapted to the mass flow rate of the shredded material in the shredding process in such a way that more than 70%, more than 80%, in particular more than 90% of the introduced coolant transitions into the vapor phase during the cooling process. If this percentage is not achieved, which can be detected, for example, by measuring an increased moisture content of the shredded material, the coolant introduction rate VS can be reduced according to the invention in this embodiment.

[0061] It can be provided that the cooling of the shredded material is controlled in the method or the shredding device according to the invention. For example, in one embodiment, the temperature of the shredded material can be measured and controlled to a predetermined target temperature of the shredded material using a control variable that determines the coolant introduction rate; in this respect, the temperature of the shredded material represents the controlled variable. Figure 3shows a corresponding control circuit 60 for implementing an embodiment of the invention for such a control, wherein the reference variable w(t) is a predetermined temperature T SOLL, which is generally dependent on the respective comminution material. The controller 61 is designed in the described embodiment as a PI or PID controller. This outputs a control signal u(t) for controlling an actuator 62, which sets the control variable volume flow VS of the coolant. In this respect, the valve device 42 of the Figure 2 . The control variable y(t) corresponds to this volume flow VS of the coolant. The control path 63 corresponds to the system part of the comminution device according to the invention between the location of the actuator 62 and the measuring element 64, ie in the embodiment according to Figure 2the valve device 42 and the temperature sensor for detecting the temperature TO of the comminuted material. A suitable mapping of the controlled variable also takes into account the influence of disturbance variables zi(t), for example the heat stored in the machine components and / or the ambient temperature as well as other external influences that affect the comminution process and / or the cooling process. The resulting temperature T0 of the comminuted material is detected via the measuring element 64 and fed back for comparison with the reference variable w(t) (setpoint temperature) and for determining the control deviation e(t), here ΔT = T SOLL -TO.

[0062] In a further embodiment, with reference to the method according to Figure 3 It may also be intended to specify a predetermined humidity level FO-setpoint as the control variable, whereby the control loop is configured according to the Figure 3shown control loop can be constructed, ie that the control loop is implemented as a single-point control for controlling a predetermined moisture content of the output material, whereby the feed rate or the volume flow VS of the coolant acts as the manipulated variable and the moisture content of the output material represents the controlled variable.

[0063] Figure 4 shows a further embodiment for the implementation of the method according to the invention, in which the control circuit 60b implements a two-point control, in which the valve device represents an actuator 62b, which is designed as a two-way valve. The actuator 62b adjusts the volume flow of the coolant such that the temperature TO of the output material remains between an upper temperature limit T SOLL_ H and a lower temperature limit T SOLL_ L. While the controllers 61 and 61b as well as the actuators 62 and 62b of the method according to the Figures 3 , 4differ, the controlled system 63 of both processes is identical, provided there are no further technical changes to the system.

[0064] Figure 5 shows a further control circuit for implementing the method according to the invention, in which a predetermined time period t0 is passed to the controller 61c as a further process variable, a maximum permissible temperature of the comminuted material T SOLL_ H is specified as a reference variable and the actual temperature TO is in turn recorded via the measuring element 64. The control with the actual temperature TO of the comminuted material as the controlled variable is carried out here by appropriately designing the controller 61c in such a way that the actuator 62c, which is in turn designed as a two-way / two-way valve, sets the volume flow of the coolant in such a way that when the upper temperature limit T SOLL_ H is reached, coolant is supplied to the comminution process for a time period t0 and thus heat output is extracted.

[0065] Figure 6shows a further control loop for implementing the method according to the invention, in which a maximum temperature of the comminuted material T SOLL_ H is used as the reference variable and the temperature TO of the comminuted material is used as the controlled variable. In contrast to the method with the control loop according to Figure 3The control loop has a controller 65, which can have both the control deviation ΔT and operating parameters or measured variables of the device as input variables, such as the drive power P, the mass flow MO or 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. From this, the controller 65 determines a control signal u(t), with which the actuator 62d, for example a valve device for adjusting a coolant flow, is controlled. In this way, for example, when controlling the temperature of the ground material TO by the control device 65, it is possible to intervene if the moisture content FO of the ground material reaches inadmissible values. For this purpose, the controller 65 can be configured to output an output signal u(t), which serves as a control signal for the actuator in order to control it to reduce the introduction rate of the coolant.Further input variables of controller 65 may include, for example, a signal indicating the direction of rotation of the comminution rotor. Controller 65 may be configured to reduce the cooling water feed rate or set it to zero if this indicator signal indicates reverse rotation of the comminution rotor. List of reference symbols

[0066] 1 Shredding device 10 Machine housing, machine frame 11 Drive motor 14 Shredding rotor, rotor 15 Shredding tools 16 Counter blade 17 Shredding chamber 17a Shredding chamber floor 18 Feeding device 19 Hopper 20 Conveyor belt 30 Temperature sensor 31 Humidity sensor, moisture sensor 32 Mass sensor 40 Water connection 41 Water line 42 Valve, valve device 43 Water volume flow measuring device 44 Water tank with level monitoring 45 Water pump, coolant pump 48 Nozzle device 48a Water nozzle, nozzle 50 Switch cabinet 55 Control device for the coolant device 56 Control device for the shredding rotor 60 Control circuit 61 Controller 62 Actuator 63 Control system 64 Measuring element 80 Shredded material / ground material 90 Bearing TOTemperature of the crushed material (Output) VSInput rate,Volume flow of the coolant FI Moisture level of the material to be shredded (input material) PElectrical drive power of the rotor drive FO Moisture level of the output material VO Volume flow of the output material MO Mass flow of the output material w(t) Reference variable T SOLL Target temperature X(t) Control variable u(t) Control signal of the actuator y(t) Control variable z I (t) Disturbance variable e(t) Control deviation,

Claims

1. Comminuting device (1) configured to carry out a comminution process with a comminuting rotor (14) that is supported on a machine frame (10) and comprises a plurality of comminuting tools (15) on its circumference, wherein the comminuting rotor (14) is disposed in a comminution chamber (17) receiving comminution material and is configured to comminute the material present in the comminution chamber, further comprising a coolant system configured to introduce into the comminution chamber a liquid coolant containing at least 80% water, and comprising a control device (55) for controlling the coolant system for setting a coolant introduction rate into the comminution chamber (17), wherein the control device (55) is configured and designed to adjust an introduction rate (VS) of the liquid, water-based coolant into the comminution process to an operating parameter of the device (1), which is dependent on the 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, characterized in that the comminuting device (1) comprises at least a moisture sensor (31) for sensing a degree of moisture (FO) of the comminuted material (80), wherein the control device (55) is designed to control to a predetermined desired degree of moisture or a predetermined desired moisture range of the comminuted material (80) with a control variable (v(t)) that determines the introduction rate (VS) of the coolant.

2. Comminuting device (1) according to claim 1, characterized in that the operating parameter of the device (1), which is dependent on the throughput of the comminution material, is a volume throughput (VO), a mass throughput (MO) of the comminution material and / or a driving power (P) of the rotor drive (11a, 11b, 11c).

3. Comminuting device (1) according to claim 1 or 2, characterized in that the control device (55) is configured and designed to perform the adjustment of the introduction rate (VS) of the coolant into the communication process to the quantity throughput of the comminution material in such a way that more than 80%, in particular more than 90%, of the coolant introduced changes from the liquid to the vapor phase when cooling the comminution material.

4. Comminuting device (1) according to any one of the preceding claims, characterized in that the cooling device comprises a connection device (40) for connection to a coolant pipe network and / or for connection to a coolant reservoir (44), as well as a coolant nozzle device for introducing coolant into the comminution process and / or into the comminution chamber (17), wherein the control device (55) for controlling the introduction rate of the coolant into the comminution chamber (17) controls at least a valve device (42) of the coolant and / or at least a coolant pump (45).

5. Comminuting device (1) according to any one of the preceding claims, characterized by at least a temperature sensor (30) for detecting the temperature (TO) of the comminuted material (80), wherein the control device (55) is designed to control to a predetermined desired temperature (TSOLL) or a predetermined desired temperature range of the comminuted material with a control variable (y(t)) that determines the introduction rate (VS) of the coolant.

6. Comminuting device (1) according to any one of claims 1 to 5, characterized by at least a temperature sensor (30) for detecting the temperature (TO) at the rotor (14), in particular a temperature in the region of one or more comminuting tools (15), wherein the control device (55) is designed to control to a predetermined desired temperature (TSOLL) or a desired temperature range of the rotor (14) with a control variable (y(t)) that determines the introduction rate (VS) of the coolant.

7. Comminuting device (1) according to any one of claims 1 to 6, characterized by a suction device designed for at least partial extraction of the water vapor generated during cooling of the comminution material.

8. Method for cooling comminution material in a comminuting device (1) that is designed for carrying out a comminution process, in which method comminution material present in a comminution chamber (17) of the comminuting device is comminuted by means of comminuting tools (15) attached to the circumference of a comminuting rotor (14), wherein during the comminution process, a liquid coolant comprising at least 80% water is introduced into the comminution chamber (17), wherein an introduction rate (VS) of the liquid, water-based coolant into the comminution process is adjusted to an operating parameter of the device, which is dependent on the quantity 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, characterized in that a degree of moisture (FO) of the comminuted material is measured and controlled to a predetermined desired degree of moisture or a predetermined desired moisture range of the comminuted material with a control variable that determines the introduction rate (VS) of the coolant.

9. Method according to claim 8, characterized in that the operating parameter of the device, which is dependent on the throughput of the comminution material, is a volume throughput (VO), a mass throughput (MO) of the comminution material and / or a driving power (P) of the rotor drive (11a, 11b, 11c).

10. Method according to any one of claims 8 or 9, characterized in that the adjustment of the introduction rate (VS) of the water-based coolant to the volume throughput of the comminution material into the comminution process is performed in such a way that more than 80%, in particular more than 90%, of the coolant introduced changes from the liquid to the vapor phase when cooling the comminution material.

11. Method according to any one of the preceding claims, characterized in that a temperature (TO) of the comminuted material (80) is measured and controlled to a predetermined desired temperature (TSOLL) or a desired temperature range of the comminuted material with a control parameter (y(t)) that determines the introduction rate (VS) of the coolant.

12. Method according to any one of the preceding claims, characterized in that a temperature at the rotor (14), in particular a temperature in the region of one or more comminution tools (15), is measured and controlled to a predetermined desired temperature (TSOLL) or a desired temperature range of the rotor with a control variable (y(t)) that determines the introduction rate of the coolant.

13. Method according to any one of claims 8 to 12, characterized in that the control includes at least the temperature (TO) and the degree of moisture (FO) of the comminuted material as controlled variables and is designed as a multi-variable control, and the respective desired value or desired value range of the comminuted material is controlled with a control variable that determines the introduction rate of the coolant.

14. Method according to any one of claims 8 to 13, characterized in that the introduction rate (VS) of the water-based coolant is set as a control variable (y(t)) of the control by means of a coolant valve device (42), wherein water vapor developing during cooling of the comminuted material is at least partially extracted.

15. Method according to any one of claims 8 to 14, characterized in that the degree of moisture (FO) of the comminution material is measured and the introduction rate (VS) is controlled as a further control variable in dependence on this.