Method and device for transferring a measurement signal from a revolving roll used in a paper making machine

• US 5,703,574 A
• Filed: 03/14/1994
• Issued: 12/30/1997
• Est. Priority Date: 03/17/1993
• Status: Expired due to Fees

• Current Assignee: Valmet Incorporated (Metso Corporation)
• Original Assignee: Valmet Incorporated (Metso Corporation)
• Inventors: Allonen, Harri
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US08/213,105
• Time in Patent Office: 1,387 Days
• Field of Search: 340/870.18, 340/870.16, 340/870.05, 340/870.07, 340/870.19, 73/862.55, 100/50, 162/198, 342/42, 342/51
• US Class Current: 340/870.07
• CPC Class Codes: B65H 2553/26 Piezoelectric sensors
• CPC Class Codes: B65H 2553/82 with regard to the direction of transport of the handled material
• CPC Class Codes: G01L 5/0085 Force sensors adapted for insertion between cooperating machine elements, e.g. for measuring the nip force between rollers

Abstract

A method and device for transferring a measurement signal from a revolving roll used in a paper making machine, in which detectors are arranged in the transverse direction of the roll, preferably uniformly spaced. Measurement signals generated by the detectors are passed to a measurement signal reading unit for reading the measurement of the detectors which is installed preferably at the end of the roll. From the measurement signal reading unit, the signals are transmitted wirelessly further as telemeter signals to a reading unit which is placed outside the roll and connected to a PC or equivalent computer. In the measurement signal reading unit for reading the measurement of the detectors, a transponder is arranged into which an unique code is coded for each detector. The signals are processed in the entire measurement process as analog signals. In the transfer of the telemeter signals between the unit for reading and measurement of the detectors and the reading unit placed outside the roll, a substantially low transfer frequency of an order of from about 100 kHz to about 150 kHz is employed.

Claims

1. In a method for transferring measurement signals generated by detectors arranged on a revolving roll of a paper making machine to a first measurement signal reading unit and wirelessly transmitting said signals from said first measurement signal reading unit to a second reading unit situated exterior to the roll and associated with a control unit, the improvement comprising the steps of:

coupling a transponder to said first measurement signal reading unit,

coupling said transponder to each of said detectors such that said transponder directs one of said detectors to generate a measurement signal upon receipt of a unique code assigned to said one of said detectors,

reading analog measurement signals generated by said detectors by means of said first measurement signal reading unit, and

transmitting said analog measurement signals from said first measurement signal reading unit at a frequency in the range of between about 100 kHz and about 150 kHz to said second reading unit.

2. The method of claim 1, further comprising the step of uniformly spacing said detectors in a transverse direction of the roll.

3. The method of claim 1, further comprising the step of arranged said first measurement signal reading unit at an end of the roll.

4. The method of claim 1, further comprising the step of converting said analog measurement signals to a pulse form in said first measurement signal reading unit, said measurement signals being transmitted by said transponder in pulse form.

5. The method of claim 1, wherein said measurement signals are transmitted by said transponder and are FSK-modulated signals.

6. The method of claim 1, further comprising the step of initiating measurement via said detectors by directing a command from said second reading unit to said transponder, the measurement unit otherwise remaining in a passive state.

7. The method of claim 1, further comprising the steps of storing the unique codes for each detector in said transponder, calibrating each detector based on the stored codes, and identifying specific ones of said detectors and reading measurements signals from the identified detector based on the stored codes.

8. The method of claim 1, further comprising the steps of forming a nip between the roll and an additional press roll, and measuring the distribution of the compression pressure in the nip in a machine direction thereof via said detectors.

9. The method of claim 1, further comprising the steps of forming a nip between the roll and an additional press roll, and measuring the distribution of the compression pressure in the nip in a transverse direction via said detectors.

10. The method of claim 1, wherein the frequency for the transfer of said measurements signals in pulse form from said first measurement signal reading unit to said second reading unit is about 130 kHz.

11. The method of claim 1, wherein said transponder is provided with one of the unique codes assigned to each of said detectors at each time to conduct individual measurements by means of said detectors.

12. A device for transferring measurement signals generated by detectors arranged on a revolving roll of a paper making machine to a first measurement signal reading unit and wirelessly transmitting said signals from said first measurement signal reading unit to a second reading unit situated exterior to the roll and associated with a control unit, comprising

a transponder arranged in said first measurement signal reading unit, said transponder being coupled to each of said detectors and structured and arranged to direct one of said detectors to generate a measurement signal upon receipt of a unique code assigned to said one of said detectors, said transponder comprising means for transmitting said measurement signals in pulse form at a frequency in the range between about 100 kHz and about 150 kHz,

said first measurement signal reading unit comprising means for processing said measurement signals received from said detectors as analog signals.

13. The device of claim 12, wherein said detectors are uniformly spaced in a transverse direction of the roll.

14. The device of claim 12, wherein said first measurement signal reading unit is arranged at an end of the roll.

15. The device of claim 12, wherein said detectors are activated by directing a command to said transponder via said second reading unit, said detectors otherwise being in a passive state.

16. The device of claim 12, wherein the unique codes of each of said detectors is used to calibrate said detectors and for identifying a specific detector to read the measurement signal generated by the specific detector.

17. The device of claim 12, wherein said first measurement signal reading unit further comprises means for converting said measurement signals in analog form generated by said detectors to a pulse form.

18. The device of claim 12, further comprising an antenna coupled to said second reading unit for receiving the wirelessly transmitted pulse form of said measurements signals from said transponder.

19. The device of claim 12, wherein the frequency of the transfer of said measurements signals in pulse form from said transponder to said second reading unit is about 130 kHz.

20. The device of claim 12, wherein said transponder is provided with one of the unique codes assigned to each of said detectors at each time to conduct individual measurements by means of said detectors.