FI114571B - Hardware and method for monitoring the condition of the machine body - Google Patents

Description

114571

EQUIPMENT AND METHOD FOR MONITORING THE MACHINE'S STATUS

The present invention relates to an apparatus as described in the preamble of independent claim 1 5 for monitoring the condition of a machine member in a paper machine or paper finishing machine. The invention further relates to a method for monitoring the condition of a machine member in a paper machine or paper finishing machine as described in the preamble of independent claim 9.

10

In papermaking, a wide web of paper is transported in different parts of a papermaking machine, and it is important to continuously monitor its passage, and in particular its tension and other properties, as well as the pressure exerted on it with different nipples. In order to observe these properties, to adjust the equipment and to avoid web breaks, it is important to control the properties of the machine elements involved in the transport and handling of the paper web. In addition, continuous measurement of paper properties (weight, thickness, humidity) is essential in papermaking to provide the highest quality end product 20.

An apparatus for measuring web tension is described in Finnish Patent 80522 (US 5052233). The apparatus of the publication is based on measuring the pressure of an air cushion between a high speed paper web and a curved surface 25 at various points in the web:> 'cross direction. The transverse measuring beam of the machine has a curved surface with regular openings through which the pressure of the air cushion affects the corresponding pressure sensors inside the beam. The differential pressure transducers used as measuring sensors measure local pressure acting through the orifice 30 compared to that introduced inside the beam. the reference pressure. In order for the entire web width to be taken into account in the measurement, the measuring sensors and the drilled holes must be densely in the cross machine direction. Obviously, this increases: the cost of manufacturing.

·: ··· 35 To measure the differential pressure of a paper machine or similar roll nipples

discloses a method in Finnish Patent 89308 (EP

114571 2 0588776B1), which uses PVDF membranes (golyvinylidene difluoride) as pressure transducers. The PVDF film is a piezoelectric film which, according to the disclosure, is coated with metal on both sides. These metallized surfaces act as pressure or force sensors. The sensors are attached to the roll body over the entire rotation surface of the roll. The mechanical quantity measured by the sensors is converted into an electrical quantity and this signal is transmitted along the conductors to a measuring unit, from which the measured values are further transmitted through a switching unit to a separate data processing system 10 for analysis. However, piezoelectric films of the kind described are heat sensitive and additionally difficult to install.

A method for monitoring roller coatings and coatings has been developed, as damage to coatings of short durability is known to cause web breaks in an unpredictable manner. It is known that the composite structure of the roll is reinforced with fibers. When added, for example, to optical fibers, such as optical fiber, such as the applicant's publication F 20000883 (US application 2001/0032924), it is more accurate to monitor the degree of roll coating damage and roll properties. Because optical fiber is relatively expensive, it becomes ·. install on the roll as cost-effectively as possible. For example !: The optical fiber can be attached to the composite structure of the roll so that the ends of the fiber are located at the ends of the roll so that it can be connected to: the necessary measuring means. The fiber can be mounted in a spiral manner around the roll 25, whereby the measurement performed by it is directed to the widest possible, with as little material as possible.

\ However, this type of installation is difficult.

It is an object of the present invention to provide a novel apparatus 30 which addresses the drawbacks of the foregoing solutions. The invention provides a simpler construction of a machine member, such as a roller, :: and a lower cost than prior art solutions. In addition, f; In the method of the invention, for monitoring the state of the machine member: ··: 35, the measurement data can be simply transferred from an external system to a roller and from a roller to an external system.

114571 3 To accomplish these purposes, the apparatus according to the invention is essentially characterized in that the apparatus comprises a magnetized conductor located in a machine member, the magnetized conductor 5 being arranged to measure features affecting the state of the mechanical member. Further, the method according to the invention is essentially characterized in that the measurement is carried out with a magnetized conductor located in the machine member, the magnetized conductor being arranged to measure features affecting the state of the machine member.

10

The magnetized conductor used in the invention comprises an electrically conductive non-magnetic conductor and a magnetic part attached thereto. It is preferably a magnetic conductor-coated electric conductor, for example a copper conductor. The coating can be applied around the conductor, for example, electrochemically. Preferably, the magnetized conductor may be positioned on a rotatably mounted machine member, such as a roll or the like, whereby an element in contact with the surface of the machine member will cause an electrical signal corresponding to pressure and pressure in the conductor. Such an element may be a continuous element, such as a paper web, passing past a machine member and extending over its surface over a given sector, or; paper machine or paper finishing machine own loop. : forming tissue. The element may also be a nip forming element in contact with the surface of the machine member, such as • <· [. a counter element or scraper forming a calender nip.

!; :: 25 • *: The magnetized conductor can advantageously be arranged as a loop measuring '* ·: measuring sensor, whereby a plurality of these sensors can be located at different points on the surface of the machine member. The quantity measured by the sensors • ·: is transmitted as an electrical signal to the switching unit, from where it is further directed to a telemetry transmitter for transmission preferably cheaply wirelessly: to a rotating external machine element • · \ '/ telemetry receiver. The electrical signal can also be transmitted indirectly (non-wirelessly, i.e., by touch) such as I .: · Slider rings used to electrify rotating machine parts.

: ·: 35 114571 4

The magnetized conductor described above is, for example, considerably inexpensive compared to optical fibers, whereby it can be considered a cost saving operation. The wire measuring technique is remarkably simple and can be used to measure both force 5 and elongation. In addition, the magnetized conductor is highly heat resistant and well suited for installation inside composite material.

The invention will be further described with reference to the accompanying drawings, the following detailed description, and the following claims. The invention is further illustrated by the drawings, in which Figure 1 schematically illustrates the basic principle of a measuring system according to the invention, Figure 2 shows an example of the structure of a magnetized conductor used in the invention, and Figures 3a-d show some preferred examples of a composite roll.

20th It should be noted in this connection that the examples shown in the figures are for the sake of clarity in the dimensions shown. However, it is clear that these dimensions do not limit objects, but actual dimensions may differ from those shown.

; Fig. 1 is a schematic view of an apparatus according to the invention.

The apparatus includes a machine element whose characteristics must be measured in order to obtain the highest quality end product.

Preferably, such a machine member is a roll 10 comprising an elastic coating 30, for example a polyurethane coating. Such a machine body. may also be a scraper arranged to remove impurities from the surface of the roll.

; f; Measurable characteristics include, by way of example, the stress on the roll cover of the roll and the stretching of the roll. To measure the described properties, the roll 10 comprises at least 114571 5 single measuring sensors 20, which may be located directly on the body of the roll 10 or within the cover, for example between the layers of the cover or on the inside surface of the cover. In some exceptional cases, the measuring sensor 20 may also be located directly on the outer surface of the roll 10.

5 If there are more than 20 measuring probes (n), they can be placed in series. Preferably, the measuring sensor sets are located on the roll 10 over substantially the entire rotational area of the roll 10. Preferably, the number of measuring sensors 20j to 20n is n = 3 to 10. The gauges can further measure other features of the roll or roll nip, such as the roll nip pressure and its distribution in particular in the cross machine direction (nip pressure profile), roll temperatures, various temperature distributions and roll deflections.

The conductor is supplied with control current as alternating current at a suitable frequency. The measured quantities are controlled from the measuring sensors 20 as voltage signals 15 through the cables 21 to the preamplifiers 22. The output voltage is dependent on the load applied to the conductor. Preferably, the preamplifiers 22 are one per sensor 20. It will be understood that there may also be only one preamplifier 22 which serves all sensors 20, for example when the measured signals are within a certain voltage range. The measurement signals are adjusted to the desired: voltage level by means of the preamplifiers 22, whereupon they are further supplied to: the switch unit 23. The switch unit 23 is controlled by a pulse sensor 25 which takes into account the rotation of the roll 10. During each revolution of the roll 10, a pulsed signal 25 is transmitted from the pulse sensor 25 to the switch unit 23 which controls the switch unit 23 so that the switch 24 closed at the time of the pulse arrival opens and the next switch 24i + 1 closes.

• »

From Figure 1, it can be seen that the switch 242 is closed with the other switches open to transmit the voltage signal from the sensor 202: 30 to the telemetry transmitter 26. The telemetry transmitter 26 is a radio transmitter,

optical transmitter or other similar radiant transmitter with signal T

* »· Is preferably routed to your wireless telemetry receiver 27.

*: * 'Telemetry can use, for example, a wireless: · communication system such as: ·: 35 radio modem, Bluetooth, WLAN, GSM or GPRS modem. It should also be noted that instead of wireless telemetry, 114571 6 can also be used for an indirect, tactile communication system such as the aforementioned slip ring. Instead of transferring data at substantially the same rate as the measurements, reading data at longer intervals can also be used. The access memory 5 may also be used in this connection. In this case, the measured values are collected in the memory or log file during operation of the machine member to be measured, from which they can be read, for example, when the machine is idle, for example during maintenance outages or the like.

10 The telemetry receiver 27 provides an output signal Vout which contains the measurement signals Vout i (i = 1 ... n) of each measuring transducer 20j. Once the entire sensor set 20 has been passed, the next measuring cycle is started from the beginning.

It should be noted that in the measuring system described above, only one telemetry channel is required, which greatly simplifies the system. The unit 15 connected to the roll 10 comprises amplifiers 22, switch units 23 and a telemetry transmitter 26. Said unit 15 may be formed as a battery-operated compact module 20, wherein e.g. the switch unit 23 is a standard integrated circuit. The measuring unit 15 is placed on a rotating roll 10, for example on its axis 14, preferably at the end of the shaft.

In the measuring arrangement of the invention, the measuring sensors 20; * 25 are implemented with a magnetized conductor 20, preferably a magnetized copper conductor, such as developed by Sensortex Inc. Figure 2 shows': the structure of such a magnetized conductor. The core of the conductor is a copper wire CU coated with a pressure sensitive magnetic coating C. The coating C may cover the copper wire CU over a certain length. As an example: Of the 30 coatings, a nickel-iron alloy (Permalloy) may be mentioned.

:, The magnetized conductor can form a loop (sensor): / as can be seen in Figure 1. Looped wiring circuits; · 'Is preferably placed on roll 10 in at least one axial row relative to the cross machine direction. Fig. 3a shows an arrangement 35 having a plurality of loop-shaped sensors at various points in the transverse direction of the machine member of the machine. The sensors can also be positioned differently.

114571 7

The single magnetized conductor may also be in the roll as a continuous wire wound spirally around the roll (Figure 3b). If such a yarn rotates, for example, 360 ° around the roll, there is always a certain portion thereof under the pressure of the web, fabric or roll nip in turn, and this arrangement also provides information about the tension or nip profile during one roll rotation. spaced-apart sensors aligned in line with the periphery of the roll.

The array of loop sensors in the rotating roll may also be arranged to run obliquely with respect to the axial direction of the roll, i.e. the axis of rotation (Fig. 3c), so that they are at different positions in the machine cross direction (roll axial). In this case, only some of the sensors can in turn become pressurized, i.e. located in the sector where the web or cloth covers the roll surface of the roll, or may be in a roll nip formed by the roll with another roll. Measurement from different points is thus carried out at different time intervals depending on the speed of rotation of the roll. In addition, the magnetized conductor may be network mounted on the coating structure, as shown in Figure 3d. In this context, the point of the measured roll coating can be determined by known signal positioning methods which utilize signal propagation time, phase shift, or the like, which correlates with distance. It is also conceivable that the entire surface area of the roll shell surface 25 is covered by loop-like sensors, with each point in the coating of the machine member being monitored.

* ·

Several sensor circuits allow monitoring of the condition of the roll, such as coating i, such that the degree of damage progression and the location of the damage:,: 30 can be deduced from the circuit malfunction. In addition, the wire; Strengthens the composite material effectively, increasing the coating t * life. It is possible to predict changes in the electrical properties of a conductor by observing its durability.

*. i 35 The magnetized conductor described above is well suited for integration into a composite material such as a roll. 114571 8 can be connected to various control and measurement methods. In the case of paper machines, advantageous applications include control of composite rolls and similar manufacturing processes. In addition, a diagnosis of the condition and condition of composite rolls can be made by observing changes in signal levels. When the roll is in use, the force exerted by the magnetized copper fiber on a continuous planar structure over the roll, such as a web for guiding / supporting the paper web, e.g. a wire, or the web itself can be measured to determine the tension or tension profile 10 of the web. Likewise, while the roll is running, the nip pressure caused by the counter element can be continuously measured under the polymer surface or inside the composite material, particularly in calendars where the roll forms a calender nip with a heated hard surface counter roll through which the paper web to be processed passes. Further, 15 magnetized conductors can be used to diagnose the release of the roll coating. For example, when installing a magnetized conductor as a network in a coating structure, it is possible to monitor the condition of the polymer / fiber roll surface throughout the surface. Further, the magnetized conductor offers the ability to optimize roll change intervals and maintenance.

The sensors of the actual roll coating (mounted on the cylindrical roll frame: coating) may also be used as belt-shaped endless loop machine members, such as belt calender belts also arranged as part of its run to form a counter caliper element. In addition, the magnetized conductor is applicable to any composite machine member I · such as, for example, a scraper, in which the conductor may be placed in a scraper structure or blade holder. Here, for example, the preferred measurement point is the blade pressure of the scraper to form the blade pressure profile.

The magnetized wire is further applicable to paper machine tissue: (e.g., a paper web supporting / supporting wire), whereby it can perform diagnostic measurements of said tissue when transmitting wirelessly or by touch or at longer intervals using memory according to the principles described above. Then. 1 to 35 conductors can also be used as a fabric reinforcement.

114571 9

It will be appreciated that by combining the various embodiments of the invention described above, various embodiments of the invention may be obtained which are in themselves within the spirit of the invention. Therefore, the foregoing examples should not be construed as limiting the invention, but embodiments of the invention may freely vary within the scope of the inventive features set forth in the claims below.

t · • · * · ► ·

Claims (15)

114571 Apparatus for monitoring the condition of a machine member in a paper machine or paper finishing machine, characterized in that the device comprises 5 magnetized conductors (20) disposed within the machine member (10), the magnetized conductor (20) being arranged to measure features. Apparatus according to claim 1, characterized in that the apparatus 10 comprises a plurality of magnetized conductors (20). Apparatus according to claim 1 or 2, characterized in that the magnetized conductor (20) is arranged in a loop. Apparatus according to claim 1 or 2, characterized in that the magnetized conductor (20) is arranged spirally around the machine member (10). Apparatus according to one of the preceding claims, characterized in that the magnetized conductor (20) is a conductor coated with a magnetic material, e.g. copper fiber. 'I I Apparatus according to one of the preceding claims, characterized in that the magnetized conductor (20) is mounted within the coating material of the machine member (10). » Apparatus according to one of the preceding claims, characterized in that a continuous planar structure, such as a paper web, 30 or a fabric, is arranged to rotate over the surface of the machine member (10), which is rotatably mounted. Apparatus according to any one of the preceding claims, characterized in that the rotary-mounted machine member (10) forms a counter element such as a nip with another roll. : ·: 35 114571 Apparatus according to one of the preceding claims, characterized in that the apparatus further comprises a switching unit (23) for receiving an electrical signal measured by a magnetized conductor (20) and a telemetry apparatus including a telemetry transmitter (26) and an external telemetry receiver (27) outside the body. A method for monitoring the condition of a machine member in a paper machine or paper finishing machine, characterized in that the measurement 10 is performed by a magnetized conductor located in the machine member (10), the magnetized conductor (20) arranged to measure features affecting the state of the machine member. Method according to claim 10, characterized in that the state of the machine member 15 is monitored at a number of different positions of the machine member (10). A method according to claim 10 or 11, characterized by transmitting the quantity measured by the magnetized conductor (20) as an electrical signal to the switching unit (23), wherein the conductor measurement signal 20 is coupled to a telemetry transmitter (26) associated with said machine element. to an external telemetry receiver (27). • · Method according to claim 10 or 11, characterized in that the quantity measured by the magnetized conductor (20) is transmitted indirectly as an electrical signal to a receiver (27) external to said machine member. A method according to any one of claims 10 to 13, characterized in that at least one of the elongation of the coating of the machine member: the strain of the coating of the machine member is measured. ► * · Iti · • i »*» Method according to one of Claims 10 to 14, characterized in that the nip pressure in the nip between the machine element and the ·: ·: 35 counter element, for example in the calender nip, or in the contact between the scraper and the rotating machine surface 114571, is measured. the force exerted by a continuous planar structure, such as a tissue or paper web, passing over the machine member. > »114571