Method and device for treating viscous, paste-like materials

Abstract

A method for treating in particular viscous, paste-like materials in a housing (1) with kneading elements (2, 3), in which at least one kneading element (2, 3) is to be monitored.

Claims

1. A method for treating viscous-pasty compositions in a housing (1) with kneading elements (2, 3), at least one kneading element (2, 3) being monitored, comprising the steps of: generating a control signal with the aid of which the state of the kneading element can be clearly assigned by the monitoring, with the control signal being generated from a drop in the pressure of a pressure medium and, when there is a drop in pressure, pressure is supplied in order to maintain a predetermined pressure of the pressure medium and further comprising the steps of maintaining a predetermined constant pressure in the kneading element, and monitoring a through flow of the pressure medium to distinguish between normal leakage and breakage of the kneading element.

2. The method as claimed in claim 1, wherein a control signal is generated from the drop in the pressure of the pressure medium over time.

3. The method as claimed in claim 1, wherein a control signal is determined from a measurement of the through flow of pressure medium in a feed line to the kneading element (2, 3).

4. The method as claimed in claim 1, wherein the monitored kneading element (2, 3) is identified.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features and details of the invention emerge from the following description of preferred exemplary embodiments and on the basis of the drawing, in which:

(2) FIG. 1 shows a schematically represented plan view of a device according to the invention for treating viscous-pasty compositions;

(3) FIG. 2 shows a perspective view of a kneading element according to the invention with monitoring elements;

(4) FIG. 3 shows a representation of an exemplary embodiment of a monitoring device in the form of a block diagram.

DETAILED DESCRIPTION

(5) Of a mixing kneader M, as shown more clearly for example in DE 43 03 852 A1, a housing 1 is represented in FIG. 1. In this housing 1 there are kneading elements 2, which are formed in a C-shaped manner. The kneading elements 2 interact with further disk-shaped kneading elements 3, which are arranged on a shaft 4. This shaft 4 is assigned a drive 5.

(6) A valve block 6, which is connected to a monitoring device 8 by way of a line 7, is also respectively indicated for a row of kneading elements 2. This monitoring device 8 may, as indicated by the arrow 9, in turn be connected to a central control device.

(7) According to FIG. 2, the kneading element 2 consists substantially of a kneading body 10, which is mounted on a housing flange 11. It is also connected to a torque sensor 12, which is assigned a tensioning device 13.

(8) In the kneading body 10 there is, indicated by dashed lines, at least one channel 14, which is in operative connection with the valve block 6 downstream of the tensioning device 13. This channel 14 may be subjected to a pressure medium by means of a pressure medium from a gas cylinder 15. The pressure in the channel 14 is monitored by way of a pressure measuring instrument 16, in particular a pressure gage.

(9) The present invention functions as follows:

(10) In the housing 1 there are preferably a plurality of kneading elements 2, as represented in FIG. 2. The kneading body 10 itself protrudes into the interior of the housing and is connected through the housing to the torque sensor 12, the tensioning device 13, the valve block 6 and the gas cylinder or pressure gage located outside the housing by means of the housing flange 11. A pressure is maintained in the channel 14 by way of the gas cylinder 15. In the case of damage to the kneading body 10, the compressed gas escapes through a possible crack into the interior of the housing, so that the pressure in the channel 14 is reduced. This is determined by the pressure gage 16, which emits a signal to the monitoring device 8. It is of course also possible here to fix a certain limit below which the pressure switch first responds. Moreover, the volume that is monitored should be chosen to be as small as possible, in order to ensure rapid, sensitive monitoring.

(11) The kneading element 2 that is possibly damaged can thus be identified by way of the corresponding line 7. The damaged kneading element can then be removed and replaced by a dummy while the installation continues to operate. The mixing kneader continues to run quite normally, that is to say without stopping.

(12) If a temperature sensor is also connected to the kneading body, the temperature, particularly in the composition to be treated, can be determined.

(13) This temperature then serves for controlling the temperature of the treatment as specifically required.

(14) It may also happen that there is an undesired misshaping of the kneading element, without the forming of a crack. According to the invention, it is provided here that the misshaping is determined by way of corresponding strain gages or else the torque sensor 12, and any damaged kneading element is exchanged.

(15) A further idea of the invention, for which protection is also independently sought, concerns using these kneading elements, designed in this way, for feeding media that are intended to be used for the treatment of the viscous-pasty composition into the housing 1.

(16) An exemplary embodiment of a monitoring device 8 according to the invention is shown in more detail in FIG. 3. Here, the kneading elements 2 are connected to a common valve block 17. For this purpose, a feed line 18 for a pressure medium is respectively provided. The valve block 17 is adjoined by a pressure medium line 19, in which a through-flow sensor 20 and a pressure reducer 21 are included toward the pressure source 15. The through-flow sensor 20 is connected to a central control unit 22, and similarly also a pressure sensor 23, which checks whether a pressure medium is present between the pressure reducer 21 and the through-flow sensor 20 in the pressure medium line 19.

(17) It is not shown any more specifically in the drawing that the control unit is of course also connected to the pressure source connection 15 and the valve block 17 and any possibly present control valves or sensors for the kneading elements 2.

(18) This monitoring device functions as follows:

(19) A nitrogen gas at about 4 bars is applied to the pressure source 15 at the pressure reducer 21 by way of the pressure medium connection. The pressure reducer 21 has the effect of reducing the pressure, for example to 1 bar. The nitrogen flows through the pressure sensor 20 and the pressure medium line 19 into the valve block 17 and is distributed there to the individual kneading elements 2.

(20) If a drop in pressure takes place, this may be attributable to a normal leakage or else to a breakage or the like of the kneading element. For the purpose of distinguishing between the two events and avoiding a false alarm, a predetermined, preferably constant pressure is always maintained in the pressure medium line 19, but the through flow is monitored, in particular with respect to the through-flow time. In the case of a normal leakage, a very small through flow takes place within a certain unit of time. An alarm is only set off if for example the through flow increases abruptly or strongly. This is an indication of a breakage or the forming of a crack in the kneading element, so that the alarm is then set off.

(21) The corresponding control signal is then used for example for switching off the drive of the shaft of a mixing kneader or switching off, switching on or otherwise influencing feed and discharge elements for starting material or product into or out of a kneading space or else for switching off or influencing heating of the kneading space or of the kneading elements.