EP0525230A1 - Verfahren und Vorrichtung für Förderseilüberwachung - Google Patents

Verfahren und Vorrichtung für Förderseilüberwachung Download PDF

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Publication number
EP0525230A1
EP0525230A1 EP91112756A EP91112756A EP0525230A1 EP 0525230 A1 EP0525230 A1 EP 0525230A1 EP 91112756 A EP91112756 A EP 91112756A EP 91112756 A EP91112756 A EP 91112756A EP 0525230 A1 EP0525230 A1 EP 0525230A1
Authority
EP
European Patent Office
Prior art keywords
rope
length
payed out
signal
time period
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91112756A
Other languages
English (en)
French (fr)
Inventor
Bernardus Johannes Bout
Peter Charles Vickers
Lourens Badenhorst Odendaal
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anglo American Corp of South Africa Ltd
Original Assignee
Anglo American Corp of South Africa Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anglo American Corp of South Africa Ltd filed Critical Anglo American Corp of South Africa Ltd
Priority to EP91112756A priority Critical patent/EP0525230A1/de
Publication of EP0525230A1 publication Critical patent/EP0525230A1/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B5/00—Applications of checking, fault-correcting, or safety devices in elevators
    • B66B5/02—Applications of checking, fault-correcting, or safety devices in elevators responsive to abnormal operating conditions
    • B66B5/14—Applications of checking, fault-correcting, or safety devices in elevators responsive to abnormal operating conditions in case of excessive loads
    • B66B5/145—Applications of checking, fault-correcting, or safety devices in elevators responsive to abnormal operating conditions in case of excessive loads electrical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B5/00—Applications of checking, fault-correcting, or safety devices in elevators
    • B66B5/0006—Monitoring devices or performance analysers

Definitions

  • This invention is concerned with a rope load monitoring system and particularly with the elimination of spurious or unwanted alarms which indicate that the loading of the rope has crossed a threshold level.
  • a winding rope In a mine shaft a winding rope has a conveyance such as a cage or skip attached to it. The winding rope is moved by a winder. To optimise the operation of the winder, without placing the winding system in a dangerous condition, it is desirable to operate the winder at maximum acceleration or deceleration rates without exceeding the permissible safe loading rating of a rope.
  • oscillations are set up in the winding rope. These oscillations manifest themselves as an increase or decrease of the measured loading of the rope at a reference point, for example at a point which is close to the winder.
  • the frequency of the rope oscillations varies with the length of rope which is payed out.
  • the frequency of rope oscillation is higher when the conveyance is near the surface and the rope length is short while the frequency is lower when the conveyance is near the bottom of the shaft and the length of rope, which is payed out, is relatively long.
  • the invention is concerned with a method of and apparatus for monitoring a winding rope which enables the incidence of unwanted alarms, that are generated by rope dynamics, to be reduced.
  • the invention provides a method of monitoring a winding rope to which is attached a conveyance which includes the step of generating an alarm signal when the load which is borne by the rope, at a predetermined location of the rope, crosses a threshold level for a period of time which exceeds a reference time period which is proportional to the length of rope payed out.
  • the length of rope payed out is preferably measured with reference to the predetermined location.
  • This location may be a point near to the winder which is used for winding the rope and thus may be at or near to the surface when the conveyance is in a shaft.
  • the method may include the steps of deriving a measure of the load which is borne by the rope, at the predetermined rope location, and which is due inter alia to the mass of the conveyance, the mass of the payed out length of rope, and dynamic effects which arise during winding, comparing this measure to a threshold level, measuring the period of time for which the measure crosses the threshold level, and generating the alarm signal when the measured period of time exceeds the reference time period which is proportional to the length of rope payed out.
  • the method may include the steps of measuring the length of rope which is payed out and of varying the reference time period so that it is directly proportional to the length of rope which is payed out.
  • the nature in which the reference time period may depend on the length of rope which is payed out may however vary in any other appropriate or desired manner.
  • the word 'cross' when reference is made to a signal crossing a threshold level, is used to indicate the situation when the signal exceeds the threshold level, or is below the threshold level, according to circumstances. Thus an overload or a slack rope condition may be indicated.
  • the method of the invention may be used to indicate an overload condition which occurs when the load borne by the rope exceeds a threshold level.
  • a slack rope condition may be detected and is indicated when the load borne by the rope is lower than a corresponding threshold level.
  • the reference time period is proportional to the length of rope which is payed out by the winder.
  • the reaction time to generate an alarm signal is relatively long when a substantial length of rope is payed out and decreases as the payed out length of rope shortens.
  • the invention also extends to apparatus for monitoring a winding rope to which is attached a conveyance which includes means for generating a first signal which is dependent on the load borne by the rope at a predetermined location of the rope, means for comparing the first signal to a threshold level and for generating a second signal when the first signal crosses the threshold level, means for monitoring the length of rope which is payed out by the winder, means for generating a reference time period which is proportional to the payed out rope length, and means for generating an alarm signal when the time period for which the second signal is generated exceeds the reference time period.
  • the reference time period may be generated in any appropriate way.
  • a pulse train is generated at a frequency which is inversely proportional to the length of payed out rope, the pulses are counted, and the reference time period is indicated when the pulse count reaches a predetermined number.
  • 'rope' includes a cable or other flexible elongate element from which a conveyance may be suspended.
  • Figure 1 of the accompanying drawings illustrates an alarm annunciator which is used to eliminate or reduce unwanted alarms that are generated by dynamic effects on a winder rope from which a conveyance is suspended, for example, in a shaft.
  • the alarm annunciator is intended to cater for genuine alarm conditions which may arise, taking into consideration the critical time which is required to react safely thereto.
  • annunciator The function of the annunciator is described hereinafter with reference to monitoring the load which is borne by a winder rope from which is suspended a cage or a skip, in a shaft. This is given merely by way of example for the use of the annunciator is not confined to this particular application.
  • annunciator is designated by the reference numeral 10.
  • modules 20, 22, 24 and 26 are known per se.
  • the module 20 provides a signal which is dependent on the length of rope payed out from the winder.
  • the module 22 is used to measure the load which is borne by the rope, and preferably this load is measured at or near the surface, i.e. near the winder, and is substantially equal to the sum of the mass of the conveyance, the mass of the payed out rope length, and loading induced in the rope by dynamic effects which arise when the rope is payed out or wound in.
  • the module 22 provides a signal which is proportional to the load imposed on the rope as well as the load imposed on the rope by the dynamic effects which arise when the rope is payed out or wound in.
  • the module 24 provides a signal which indicates when the brakes of the winder are on or off.
  • the module 26 provides a signal which is dependent on the speed of the winder.
  • the annunciator includes two output terminals 28 and 30 which respectively are connected to a data logger, not shown, and to an alarm relay, also not shown.
  • the annunciator includes an inverting amplifier 32 the gain of which is adjustable by means of a potentiometer 34, an inverting summing amplifier 36, the gain of which is adjustable by means of a potentiometer 38, a voltage controlled oscillator 40, a low pass filter 42, a level or threshold detector 44, a logic gate 46.
  • a counter 48 a logic circuit 50 which has inputs from the counter 48, the threshold detector 44, and the input terminals 16 and 18, a buffer 52 which has its input connected to the output of the logic circuit 50 and its output connected to the output terminal 28, and a relay driver 54 which is connected between the logic circuit 50 and the output terminal 30.
  • a signal which is produced by the module 20 is applied to the input terminal 12 and the potentiometer 38 associated with the summing amplifier 36 is adjusted to set the highest output frequency, f2, of the voltage controlled oscillator 40 to the required value.
  • the conveyance is then moved to the lowest level in the shaft.
  • the signal which is input to the terminal 12 varies accordingly and the potentiometer 34 which is associated with the variable gain amplifier 32 is adjusted to set the lowest output frequency f1 of the voltage controlled oscillator 40 to the required value.
  • the frequency range of the oscillator 40 is shown in Figure 2 as a function of the payed out length of the rope. It is apparent that the frequency of the oscillator is inversely proportional to the payed out rope length and varies accordingly as the conveyance moves up and down the shaft.
  • the load which is borne by the rope is measured by the module 22 and the signal produced by this module, after it has been conditioned in the filter 42, is input to the level detector 44 where it is compared to a reference signal, determined in accordance with known criteria, which is input to the level detector from a potentiometer 56.
  • the annunciator is intended to detect an overload condition.
  • this is indicated by the level detector 44 which outputs an appropriate signal to the logic gate 46, the counter 48, and the logic circuit 50.
  • the logic gate 46 is enabled and pulses produced by the voltage controlled oscillator 40 are counted by the counter 48.
  • the count in the counter reaches a predetermined value, which is fixed taking the characteristics of the winder and shaft into consideration, the counter generates an output signal which enables the logic circuit 50 provided signals are present at the terminals 16 and 18 indicating respectively that the winder brakes are off and that the winder speed is below a predetermined speed.
  • an alarm signal is generated by the logic circuit 50 and applied to the buffer 52 and relay driver 54.
  • the buffer produces a signal, at the terminal 28, which is supplied to a data logger while the relay driver 54 generates a signal which is available at the terminal 30 and which is used to activate an appropriate alarm and to initiate appropriate action.
  • the output signal from the threshold detector 44 changes indicating that an overload condition no longer exists.
  • the logic gate 46 is disabled as is the logic circuit 50, and the counter 48 is reset to zero.
  • the logic gate 46 is disabled. This prevents the output pulses from the voltage controlled oscillator 40 from further advancing the counter 48. The counter is then reset to zero and the logic circuit 50 is kept disabled. The alarm signal from the threshold detector 44 cannot therefore be routed to the output drivers 52 and 54.
  • the system thus enables an alarm condition, as indicated by the level detector 44, to be tolerated for a period of time which is proportional to the length of rope which is payed out at that moment.
  • the length of rope is used to control the frequency of oscillation of the oscillator 40 and its frequency is inversely proportional to the rope length.
  • the time interval between successive pulses output by the oscillator increases as rope length increases and this means that the counter 48 reaches its predetermined count in a time interval which is proportional to the payed out length of rope.
  • the predetermined time interval which is effectively generated by the counter 48 is longer than the period for which an alarm condition is generated by dynamic effects on the rope during winding. Thus dynamic effects can be catered for and no alarm is generated when the load on the rope briefly exceeds the overload rating of the rope. On the other hand if this rating is exceeded for more than the predetermined period an alarm condition is generated.
  • reaction time interval is dependent on the length of rope which is payed out at the moment.
  • the longer the length of rope that is payed out the longer is the reaction time to the alarm condition.
  • the reaction time becomes progressively shorter as the conveyance suspended from the rope moves towards the surface and, at surface, an alarm condition is reacted to immediately.
  • a longer reaction time can be tolerated when the conveyance is far from surface for the elasticity of the longer winding rope provides a degree of safety.

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  • Control And Safety Of Cranes (AREA)
EP91112756A 1991-07-30 1991-07-30 Verfahren und Vorrichtung für Förderseilüberwachung Withdrawn EP0525230A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP91112756A EP0525230A1 (de) 1991-07-30 1991-07-30 Verfahren und Vorrichtung für Förderseilüberwachung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP91112756A EP0525230A1 (de) 1991-07-30 1991-07-30 Verfahren und Vorrichtung für Förderseilüberwachung

Publications (1)

Publication Number Publication Date
EP0525230A1 true EP0525230A1 (de) 1993-02-03

Family

ID=8206994

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91112756A Withdrawn EP0525230A1 (de) 1991-07-30 1991-07-30 Verfahren und Vorrichtung für Förderseilüberwachung

Country Status (1)

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EP (1) EP0525230A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104828730A (zh) * 2015-04-15 2015-08-12 杭州航海仪器有限公司 船用电动绞车收放缆阵多重安全保护方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2349986A1 (fr) * 1976-04-28 1977-11-25 Munck Continental Sa Limiteur de charge
GB2027301A (en) * 1978-06-17 1980-02-13 Westinghouse Brake & Signal Detecting interruption of signals
GB2055488A (en) * 1979-07-26 1981-03-04 Isetron Ind Sicherheitselektro Overload protection in lifting apparatus
GB2090416A (en) * 1980-12-24 1982-07-07 Mannesmann Ag Apparatus for indicating the wear of a lifting device such as a hoist
EP0103162A2 (de) * 1982-08-13 1984-03-21 Bayerische Bühnenbau GmbH Mess- und Steuereinrichtung für an Seilen befestigte Lasten, insbesondere für Theaterpunktzüge

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2349986A1 (fr) * 1976-04-28 1977-11-25 Munck Continental Sa Limiteur de charge
GB2027301A (en) * 1978-06-17 1980-02-13 Westinghouse Brake & Signal Detecting interruption of signals
GB2055488A (en) * 1979-07-26 1981-03-04 Isetron Ind Sicherheitselektro Overload protection in lifting apparatus
GB2090416A (en) * 1980-12-24 1982-07-07 Mannesmann Ag Apparatus for indicating the wear of a lifting device such as a hoist
EP0103162A2 (de) * 1982-08-13 1984-03-21 Bayerische Bühnenbau GmbH Mess- und Steuereinrichtung für an Seilen befestigte Lasten, insbesondere für Theaterpunktzüge

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104828730A (zh) * 2015-04-15 2015-08-12 杭州航海仪器有限公司 船用电动绞车收放缆阵多重安全保护方法
CN104828730B (zh) * 2015-04-15 2017-04-12 杭州航海仪器有限公司 船用电动绞车收放缆阵多重安全保护方法

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