VIBRATION MEASURING ASSEMBLY

Abstract

A device for treating a web of fibrous material, the device comprising: a sensor for detecting vibrations; a multi-part housing including a cover; and a plurality of fiber treatment tools arranged inside the multi-part housing, the plurality of fiber treatment tools including a plurality of treatment profiles facing one another, being arranged spaced apart from each other so as to form at least one treatment gap with the plurality of treatment profiles, and being mounted rotatably relative to one another, at least one of the plurality of fiber treatment tools being mounted axially movable in the multi-part housing so as to be configured for adjusting a width of the at least one treatment gap between the plurality of treatment profiles facing each other, at least one of the plurality of fiber treatment tools being supported by a part of the multi-part housing, the sensor being arranged on the multi-part housing.

Claims

1. A device for treating a web of fibrous material, the device comprising: a sensor for detecting a plurality of vibrations; a multi-part housing including a cover; and a plurality of fiber treatment tools arranged inside the multi-part housing, the plurality of fiber treatment tools including a plurality of treatment profiles facing one another, being arranged spaced apart from each other so as to form at least one treatment gap with the plurality of treatment profiles, and being mounted rotatably relative to one another, at least one of the plurality of fiber treatment tools being mounted axially movable in the multi-part housing so as to be configured for adjusting a width of the at least one treatment gap between the plurality of treatment profiles facing each other, at least one of the plurality of fiber treatment tools being supported by a part of the multi-part housing, the sensor being arranged on the multi-part housing.

2. The device according to claim 1, wherein the multi-part housing includes an outside, the sensor being arranged on the outside of the multi-part housing.

3. The device according to claim 1, wherein the sensor for detecting the plurality of vibrations is formed by a uniaxial acceleration recorder.

4. The device according to claim 3, wherein the sensor formed as the uniaxial acceleration recorder is aligned for detecting in a direction of the width of the at least one treatment gap.

5. The device according to claim 1, further comprising at least two hinges, wherein the cover is rotatably mounted about a joint axis by way of the at least two hinges, the sensor being arranged in a region of the device between the at least two hinges on the multi-part housing, the region between the at least two hinges being limited by planes extending perpendicular relative to the joint axis.

6. The device according to claim 5, wherein the sensor is arranged in the region of the device between the at least two hinges on the cover.

7. The device according to claim 5, wherein the joint axis is vertically extending.

8. The device according to claim 5, wherein the cover includes a hinge-side half, the sensor being arranged on the hinge-side half of the cover.

9. The device according to claim 1, further comprising a high-pass filter of at least 4000 HZ, the high-pass filter being configured for signal processing of a plurality of signals of the sensor.

10. The device according to claim 1, further comprising a control unit including a memory and an evaluation unit, the memory being configured for storing a plurality of standard deviations, the evaluation device being configured for detecting the malfunction when a predetermined number of time intervals of a predetermined duration which are impacted by the plurality of vibrations are exceeded, wherein at least half of the predetermined number of time intervals are impacted by the plurality of vibrations.

11. The device according to claim 10, wherein at least three of five of the predetermined number of time intervals are impacted by the plurality of vibrations.

12. The device according to claim 10, wherein the predetermined duration of a respective one of the predetermined number of time intervals is at least 2 seconds.

13. The device according to claim 10, wherein the predetermined duration of the predetermined number of time intervals is the same.

14. A method for detecting a malfunction, the method comprising the steps of: detecting a vibration acceleration by an at least uniaxial vibration sensor; filtering a plurality of vibration signals by way of a high-pass filter; determining, upon detecting a predetermined vibration threshold value being exceeded, the vibration acceleration over a predetermined number of time intervals which are predetermined; and signaling a malfunction if the predetermined vibration threshold value is exceeded in at least half of the time intervals which are consecutive.

15. The method according to claim 14, wherein the step of signaling the malfunction occurs if the predetermined vibration threshold value is exceeded in at least three of five ones of the time intervals.

16. The method according to claim 14, wherein a measurement occurs over a respective one of the time intervals of at least 2 seconds.

17. The method according to claim 14, wherein a determination of a standard deviation from a plurality of recorded vibration acceleration signals is continuously conducted for a determination of a vibration intensity, and the standard deviation is used for a detection of the malfunction.

18. The method according to claim 14, wherein, following each one of a start-up, a basic value of a plurality of operation-related vibrations is taught to eliminate a plurality of basic vibrations caused by an environment.

19. The method according to claim 14, wherein an axial position of at least one treatment tool of a housing part is adjusted in order to widen at least one treatment gap when the malfunction is detected.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of at least one embodiment of the invention taken in conjunction with the accompanying drawing, wherein:

[0034] FIG. 1 is a double disc refiner in open condition;

[0035] FIG. 2 is a side view of the closed refiner;

[0036] FIG. 3 is another side view of the closed refiner;

[0037] FIG. 4 is a schematic cross-section through the refiner;

[0038] FIG. 5 is a representation of the sensor data and the time interval method; and

[0039] FIG. 6 is a recording of acceleration data in comparison to the standard deviation.

[0040] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrate at least one embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0041] The housing of the arrangement for refining fibrous material as shown in FIG. 4, includes two parallel treatment gaps 11, 12 extending perpendicular relative to axis of rotation 5, each formed by a non-rotating treatment tool 1, 4 and a flat treatment tool 2, 3 rotating about axis 5.

[0042] The annular treatment profile 10 of aforementioned treatment tools 1, 2, 3, 4 each facing treatment gap 11, 12, is formed by refining fillings having a plurality of substantially radially extending refining bars on the profile side, so that this profile is formed by said refining bars and the grooves positioned between them.

[0043] The fiber suspension to be refined herein enters one of the two treatment gaps 11, 12 between the refining fillings via an inlet through the center of the device. The fibrous suspension then passes radially to the outside through the interacting treatment tools 1, 2, 3, 4 and accumulates in the adjacent annular space.

[0044] While at least a portion of the thus treated fibrous suspension leaves this annular space through a drain, the other portion of the fibrous suspension may, under certain circumstances, flow back through the grooves of the non-rotating treatment tools 1, 4 through a section of their length.

[0045] The cross-section of the refining bars, also referred to as knives, is generally rectangular, although there are other shapes. The upper side of these refining bars, in other words the surfaces supporting the refining edges, which conclude the respective refining filling in the direction of the mating filling, are positioned in the radial plane.

[0046] The grooves extending between the refining bars also have a rectangular cross-section and serve as flow channels for the fibrous suspension. The groove depth is usually between 2 and 20 mm.

[0047] In the herein illustrated refining arrangement, treatment tool 2, 3 of both treatment gaps 11, 12 adjacent to the respective other treatment gap 11, 12 rotates with an axis 5 extending through the center of treatment profile 10. These rotating treatment tools 2, 3 are detachably mounted to a common base plate 14 which is axially movable on the rotating axis 5 and rotates with it. As can be seen in FIG. 2, axis 5 is driven by a drive 16 coupled via a gearbox 15.

[0048] According to FIGS. 1 and 3, the housing of the device consists in particular of a large, fixed housing part 7 supported on a machine foundation 17 and a smaller housing part 8 in the embodiment of a cover which can be pivoted away from the latter.

[0049] These two housing parts 7, 8, each of which support a non-rotating treatment tool 1, 4, are coupled to each other via a joint 9, which is rotatable about joint axis 13 and is designed herein in two parts as an example.

[0050] Whereas non-rotating treatment tool 4 is firmly connected with stationary housing part 7, the other non-rotating treatment tool 1 can be moved axially along axis of rotation 5 via an adjustment device 18 for adjusting the overall width of both treatment gaps 11, 12.

[0051] Since base plate 14 is mounted in a floating manner on axis 5, its axial position is adjusted by the interaction of the hydraulic forces acting in the two treatment gaps 11, 12.

[0052] Depending on the flow rate as well as the wear of both treatment gaps 11, 12, the situation could occur that the width of treatment gaps 11, 12 differs, which can have a corresponding negative effect on the quality of the fiber treatment and wear.

[0053] Moreover, an increased friction value in the axially floating mounting of rotating base plate 14 (with its treatment tools 2, 3) on axis 5 could cause the rotor to not center itself.

[0054] The result may be an insufficiently large fiber suspension cushion in a treatment gap 11, 12 or even contact of the treatment tools 1, 2, 3, 4.

[0055] During contact of treatment tools 1, 2, 3, 4 of a treatment gap 11, 12, an exponential wear of treatment profile 10 of said treatment tools 1, 2, 3, 4 occurs over the duration of the contact.

[0056] In order to prevent this increased wear, the vibrations of the device are monitored via at least one sensor 6. Sensor 6 is designed as a uniaxial acceleration recorder with a piezoelectric measuring principle and is aligned parallel to axis 5.

[0057] Herein it has proved advantageous for reliable detection of a critical operating state that sensor 6 detects vibrations in the range between 5 and 12 kHz and thereby measures the vibration acceleration.

[0058] So that low-frequency basic vibrations of the environment can be considered in the evaluation of the signals of sensor 6, at least one further sensor detects vibrations in the area of gearbox 15.

[0059] For reliable measurement of vibrations in order to minimize wear in such devices for treatment of fibrous material, at least one sensor 6 is arranged in the housing near joint 9. Based on the higher demands, this region offers greater rigidity.

[0060] As shown in FIG. 3, sensor 6 is located in housing part 8—which can be swiveled away via joint 9—and approximately between the two door hinges of joint 9, whereby the straight line between sensor 6 and shaft 5 extends approximately perpendicular to joint axis 13.

[0061] A critical operating state of the device in terms of wear, in particular contact between treatment tools 1, 2, 3, 4 of a treatment gap 11, 12, can be concluded if the vibration intensity exceeds a previously determined vibration threshold value via sensor 6 of swiveling housing part 8.

[0062] Vibration signals are plotted in FIG. 5. To exclude false signals, particularly in the case of only very brief contact between treatment tools 1, 2, 3, 4, the control system of the device assumes that two treatment tools 1, 2, 3, 4 are in contact only if the specified vibration threshold value is exceeded at least once in each of at least three of five consecutive specified time intervals 25. Time intervals 28 impacted by vibrations, and discreet time intervals are shown. Measurement windows with respectively 5 time intervals are shown, wherein a malfunction with signaling occurs only in the middle measurement window, since only in this measurement window a minimum number of time intervals impacted by vibrations is detected.

[0063] FIG. 6 shows a diagram in which the vibration acceleration and, in comparison, the standard deviation of the vibration acceleration are plotted against time.

[0064] If the control system of the device—via this vibration measurement—detects a critical operating state for treatment tools 1, 2, 3, 4, the axial position of non-rotating treatment tool 1 that is supported by swiveling housing part 8 is adjusted accordingly by adjusting device 18 in order to widen treatment gap 11, 12.

[0065] The present invention can also be used with conical refining surfaces, where the cone axis coincides with the axis of rotation 5, and with devices having only one treatment gap.

[0066] In summary, the present invention relates to a device and a method for fiber treatment. The device has a multi-part housing in which at least a first treatment tool (1, 3) and a second treatment tool (2, 4) are arranged. Treatment tools (1, 2, 3, 4) have a rotationally symmetrical shape and are arranged coaxially to one another and can be rotated relative to one another about a common axis (5). Two treatment tools (1, 2, 3, 4) respectively define a treatment gap (11, 12) through which the fibrous material flows radially. Two housing parts (7, 8), each supporting at least one treatment tool (1, 2, 3, 4), are connected with one another via a joint (9) which can rotate about a joint axis (13). Contact between two treatment tools (1, 2, 3, 4) is reliably detected by at least one sensor (6) arranged on the housing, optionally an externally arranged sensor (6) for detecting vibrations.

COMPONENT IDENTIFICATION LISTING

[0067] 1 Non-rotating treatment tool, axially adjustable [0068] 2 treatment tool, flat and rotating [0069] 3 treatment tool, flat and rotating [0070] 4 non-rotating treatment tool [0071] 5 axis of rotation [0072] 6 sensor [0073] 7 housing part, fixed [0074] 8 housing part, cover [0075] 9 joint, hinge [0076] 10 treatment profile [0077] 11 treatment gap [0078] 12 treatment gap [0079] 13 joint axis [0080] 14 base plate [0081] 15 gearbox [0082] 16 drive [0083] 17 machine foundation [0084] 18 adjustment device [0085] 20 device [0086] 21 vibration acceleration [0087] 22 standard deviation of vibration acceleration [0088] 25 malfunction, clash [0089] 26 time interval [0090] 27 time interval, normal operation [0091] 28 time interval impacted by vibration

[0092] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.