CLIAMS:We Claim:

1. A portable conveyor speed sensing system comprising:
an enclosure housing a proximity sensor involving switching based on sensing of a rotatable striker within said housing, said rotation of said rotatable striker operatively connected to a shaft end inside said housing and the other end of the shaft outside the housing connected to a rotating wheel assembly which rotates on contact with the moving conveyor ;
the rotating wheel providing rotary motion to the shaft which in turn rotates the rotatable striker ;
said proximity sensor sensing the rotation of said striker;
a cooperative controller operatively connected to said proximity sensor which generates pulse based on the sensed striker based on which the controller is activated to control the conveyor.

2. A portable conveyor speed sensing system as claimed in claim 1 comprising frame and support structure for mounting the enclosure with said shaft and rotating wheel at any desired location of the conveyor preferably away from the discharge end/chute of the conveyor.

3. A portable conveyor speed sensing system as claimed in anyone of claims 1 or 2 which is adapted for mounting at the return side of the conveyor which is close to one of the return idler but far from the discharge chute.

4. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 3 wherein said proximity sensor comprises a zero speed switch (ZSS) which works on electrical switch and generates output when said striker comes in front of its sensing tips within a specified distance preferably 5 to 10 mm.

5. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 4 wherein a set of strikers are mounted/welded on the non drive part of the rotating shaft.

6. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 5 wherein said enclosure comprises a sealed enclosure isolated from outside disturbances including falling of materials,shifting of pulley and the like.

7. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 6 wherein said striker comprises MS –thin plate as fins and mounted on said shaft inside the enclosure and said proximity sensor senses the metallic fins of rotating striker when it comes near its sensing range and gives electrical signal to the controller.

8. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 7 wherein said controller comprises an electronic controller adapted to sense signal from the sensor and condition it to give switchable output for stopping of conveyor if and when required.

9. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 8 comprising of mounting arrangement comprising a flexible arm for mounting of said enclosure and wheel and its assembly.

10. A conveyor system comprising a portable conveyor speed sensing system as claimed in anyone of claims 1 to 9 comprising:
a conveyor arrangement having a discharge side end and a return side end;
said portable conveyor speed sensing system placed far from said discharge end having discharge chute involving said mounting arrangement whereby the belt motion rotates the rotary wheel which in turn rotates the shaft and the striker housed in said enclosure for sensing by the proximity sensor also housed in said enclosure.

11. A conveyor system as claimed in claim 10 wherein said enclosure and wheel assembly is mounted with respect to the conveyor involving a flexible arm and a fixed arm providing for rigid support to the enclosure and wheel assembly.

12. A conveyor system as claimed in anyone of claims 10 or 11 wherein said enclosure housing the striker and the proximity sensor is mounted at the return side of the conveyor which is close to one of the return idler which is far from the discharge chute.
Dated this the 8th day of August, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)
,TagSPECI:FIELD OF THE INVENTION

The present invention is directed to a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages. More particularly, the present invention is directed to provide a portable conveyor speed sensing system having enclosed proximity sensor assembly along with sensing striker in which sensor is protected in a manner so as not to be affected by external condition of mounting location e.g. material deposition/spillage etc and also not get disturbed by pulley shifting. The enclosure arrangement can be installed anywhere on the conveyor away from the head pulley and the discharge chute and preferably at the return side of the conveyor which is close to one of the return idler but far from discharge chute without compromising of its purpose of use so as to reliably sense the speed of conveyor avoiding any speed related damages.

BACKGROUND OF THE INVENTION

It is well known that ZSS(Zero Speed Switch) as a field device is used to notify the loss of speed e.g angular or linear displacement of the object than rated normal speed as predefine and specified operating standard. This ZSS includes a proximity sensor( sensor which works as an electrical switch & gives output when a piece of metal (striker) will come in front of its sensing tips within a specified sensing distance) an electronics controller with a potential free contact. The proximity sensor detect speed which is physical quantity and convert it in electrical quantity, measuring in forms of pulses for later evaluation done in controller to count the obtained pulsations those are directly proportional to speed of object.

This ZSS device is conventionally used in bulk material handling/processing systems to monitor speeds of belt conveyors, screw conveyors, bucket elevators, rotary feeder shafts, rotating drums and other types of rotating machinery. In any case machine speed is reduced from its normal speed or comes down to zero due to either internal problem like failure of equipment itself, cut in pulling elements, failure of coupling, resulting from broken belts, overloads, or belt slippages etc or external problem like jamming, it protect elevators, feeders and conveyors from speed related damage.

In applicants steel plant, P1( Product belt conveyor no.-1) is very important solo conveyor which is conveying the produced Sinter from discharge of Sinter cooler to next parallel set of conveyor P-2 & P-3. It is a part of transporting conveyor system which is used to conveying Sinter product for further processing like screening and feeding to Blast furnace.

In order to protect such valuable machine (P1 conveyor) against speed related damage resulting from broken belts, overloads, or belt slippages, ZSS is suitable field device being used to overcome above mentioned risk factor causing machine down & having direct impact of maintenance and production due to hampered sintering process. Conventionally the proximity sensor of ZSS is placed at the snub pulley of P1 conveyor which is very close to the head pulley and the discharge chute.

It is experienced in the conventional sinter production and transportation based plant operations that material jamming problems occur occasionally either due to big size sinter which cannot pass through discharge gate of chute or due to trapping of any wider dimensioned foreign material viz, liner plate, MS plate, MS angle & channels etc. Due to jam in chute opening, material starts overflowing form the chute & starts accumulating in , above & around the drive end (Head End) pulley and conveyor and its surrounding area. Since the rate of flow of material is very large in the range of approx. 400-500 Ton per hour, within a fraction of minute it creates havoc situation in the area, during the process snub pulley is also filled with such spilled material, at the same time conveyor is already in motion, if not got stopped, situation become worse and consequently will lead to damage of belt. In this situation ZSS should come into the picture and give the signal to stop the belt by detecting the slower speed ( due to material jamming on the conveyor).As explained earlier sensor is the element which detects the slow speed and give signal to controller for initiating the command. However, it is the experience in conventional operation of sinter carrying P1 conveyor that, since mounting of Proximity sensor & its striker was on Snub pulley in existing system, in case of jamming of material & even some times in normal running also material pieces stuck in snub pulley and damaging the proximity sensor which in turn defeating the purpose of ZSS. Because of the chute jamming whenever accumulation of material occurs, the gap between the proximity sensor and the striker gets misaligned, even many times the proximity got damaged due to same reason.

There has been thus a need in the art to developing a portable conveyor speed sensing system for sinter transporting conveyor at exit of discharge chute which would not be affected by outside disturbances like, falling of material, shifting of pulley & other external impact on sensor mounting assembly which in turn protecting the sensor from being damaged and ensure conveyor speed sensing and damage control in a reliable manner.

OBJECTS OF THE INVENTION

The basic object of the present invention is thus directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages in reliable manner avoiding misalignment or frequent damage of proximity sensor due to chute jamming and material accumulation.

A further object of the present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages wherein the sensor as well as striker is mounted in ZSS enclosure located away from snub pulley near header pulley and the discharge chute.

A still further object of the present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages wherein the striker is rotated by shaft mounted with a rotating wheel which remain in contact with the conveyor.

A still further object of the present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages wherein the system ensure stopping of belt conveyor in case of elongation & slippage due to hot sinter.

A still further object of the present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages wherein the system ensure prevention of damaging of belt due to slipping and rubbing.

A still further object of the present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages wherein the system ensure saving of man hour and avoid delay due to conveyor/sensor damage.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is thus directed to a portable conveyor speed sensing system comprising:
an enclosure housing a proximity sensor involving switching based on sensing of a rotatable striker within said housing, said rotation of said rotatable striker operatively connected to a shaft end inside said housing and the other end of the shaft outside the housing connected to a rotating wheel assembly which rotates on contact with the moving conveyor ;
the rotating wheel providing rotary motion to the shaft which in turn rotates the rotatable striker ;
said proximity sensor sensing the rotation of said striker;

a cooperative controller operatively connected to said proximity sensor which generates pulse based on the sensed striker based on which the controller is activated to control the conveyor.

Another aspect of the present invention is directed to a portable conveyor speed sensing system comprising frame and support structure for mounting the enclosure with said shaft and rotating wheel at any desired location of the conveyor preferably away from the discharge end/chute of the conveyor.

A further aspect of the present invention is directed to a portable conveyor speed sensing system which is adapted for mounting at the return side of the conveyor which is close to one of the return idler but far from the discharge chute.

A still further aspect of the present invention is directed to a portable conveyor speed sensing system wherein said proximity sensor comprises a zero speed switch (ZSS) which works on electrical switch and generates output when said striker comes in front of its sensing tips within a specified distance preferably 5 to 10 mm.

A still further aspect of the present invention is directed to a portable conveyor speed sensing system wherein a set of strikers are mounted/welded on the non drive part of the rotating shaft.

A still further aspect of the present invention is directed to a portable conveyor speed sensing system wherein said enclosure comprises a sealed enclosure isolated from outside disturbances including falling of materials, shifting of pulley and the like.

Another aspect of the present invention is directed to a portable conveyor speed sensing system wherein said striker comprises MS –thin plate as fins and mounted on said shaft inside the enclosure and said proximity sensor senses the metallic fins of rotating striker when it comes near its sensing range and gives electrical signal to the controller.

Yet another aspect of the present invention is directed to a portable conveyor speed sensing system wherein said controller comprises an electronic controller adapted to sense signal from the sensor and condition it to give switchable output for stopping of conveyor if and when required.

A further aspect of the present invention is directed to a portable conveyor speed sensing system comprising of mounting arrangement comprising a flexible arm for mounting of said enclosure and wheel and its assembly.

According to a further aspect of the present invention, the same is directed to a conveyor system comprising a portable conveyor speed sensing system as described above comprising:
a conveyor arrangement having a discharge side end and a return side end;
said portable conveyor speed sensing system placed far from said discharge end having discharge chute involving said mounting arrangement whereby the belt motion rotates the rotary wheel which in turn rotates the shaft and the striker housed in said enclosure for sensing by the proximity sensor also housed in said enclosure.

A further aspect of the present invention is directed to a conveyor system wherein said enclosure and wheel assembly is mounted with respect to the conveyor involving a flexible arm and a fixed arm providing for rigid support to the enclosure and wheel assembly.

A still further aspect of the present invention is directed to a conveyor system wherein said enclosure housing the striker and the proximity sensor is mounted at the return side of the conveyor which is close to one of the return idler which is far from the discharge chute.

The objects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying non limiting illustrative drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1: is the schematic layout of Conveyor Belt showing the conventional disposition of ZSS including proximity sensor in relation to conveyor and snub pulley.

Figure 2: is the schematic arrangement of the ZSS enclosure based portable conveyor speed sensing system according to the present invention showing the mounting location away from discharge chute.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES

The present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages in reliable manner avoiding misalignment or frequent damage of proximity sensor due to chute jamming and material accumulation.

Accompanying Figure 1 is the schematic layout of Conveyor Belt showing the conventional disposition of ZSS including proximity sensor in relation to conveyor and snub pulley. Earlier the proxy was placed at the snub pulley of P1 conveyor which is very close to the head pulley and the discharge chute as shown in figure. Because of this whenever material jamming in discharge chute occurs due to accumulation of material, the gap between the proximity sensor and the striker gets misaligned, even many times the proximity got damaged due to same reason. P1 is the conveyor for conveying the produced Sinter from discharge of Sinter cooler to next parallel set of conveyor. It is a part of transporting conveyor system which is used to conveying Sinter product for further processing like screening and feeding to Blast furnace. In conventional operation of sinter carrying P1 conveyor, since mounting of Proximity sensor & its striker was on Snub pulley in existing speed detection system, in case of jamming of material & even some times in normal running also material pieces stuck in snub pulley and damaging the proximity sensor which in turn defeating the purpose of ZSS, resulting in considerable loss of production and process delay.

To avoid the above stated disadvantage and limitation of the existing ZSS based speed sensing device for conveyors, a fabricated ZSS enclosure based conveyor belt speed sensing system for reliable speed sensing and operational control of sinter transporting conveyor for conveying the produced Sinter from discharge of Sinter cooler to next stage, has been conceived and implemented by way of the present invention which would not be affected by outside disturbances like, falling of material, shifting of pulley and other external impact on sensor mounting assembly.

Accompanying Figure 2 is the schematic arrangement of the ZSS enclosure based portable conveyor speed sensing system according to the present invention favouring mounting of the speed sensing system at any suitable location away from discharge chute. To avoid the above mentioned problem, an enclosure unit for housing proximity sensor and striker has been developed in-house. The developed new enclosure arrangement is mounted at the return side of the conveyor which is close to one of the return idler but far from discharge chute.

Inside the enclosure arrangement, movable striker arrangement has been done with the help of a shaft attached to a rotating wheel. Striker rotates in the same way as initially when it was welded on snub pulley. As striker rotates, the proximity sensor which has also been mounted within the enclosure senses its movement and give pulses to controller. Since this developed assembly needs rotation with respect to main equipment (in this case the conveyor movement), it has been mounted on the return side of the conveyor at a suitable convenient location. Thus in the new system, sensing devices i.e. sensor and striker are mounted in a sealed enclosure, which is totally isolating them from outside disturbances like, falling of material, shifting of pulley & other external impact on mounting assembly which in turn protecting the sensor from being damaged.

Thus in the improved speed sensing system for conveyor speed sensing according to the present invention, the fabricated ZSS Enclosure(1) is provided for protection of sensor & striker mounted within the enclosure from outside disturbances like, falling of material, shifting of pulley etc. The Striker (2) is a MS- thin plate designed as fins and mounted on a rotating shaft(3) inside the enclosure(1), work as sensing object for sensor related to motion of conveyor. Rotating wheel(4) is a wheel, which is coupled to striker through the rotating shaft(3), placed on conveyor, so that it rotates due to friction while conveyor moves. The Proximity sensor(5) is installed within the enclosure(1) for sensing movement of the metallic fins of rotating striker(2) when comes near its sensing range and give electrical signal to Zero speed switch(ZSS) (6)/controller.

ZSS (6) is the unit having electronics inside, senses the signal from sensor and conditioned it to give switchable output which is being used for stopping of conveyor motor by the MCC(7)(motor control centre). MCC consists of various electrical and electronics component assembled to start, stop and protection of motor viz. Fuses, Power contactor, overload relay etc.

The enclosure(1) assembly is mounted at a suitable location in relation to the conveyor with the help of a Fixed arm(8) that is welded with fixed structure of conveyor to give a rigid support to the enclosure assembly and a Flexible Arm(9) connected to said Fixed arm(8) used for mounting of enclosure and wheel assembly with required positioning in relation to conveyor.

Thus in the speed sensing system for detecting conveyor belt speed according to the present invention involving an enclosure assembly for housing the proximity sensor and the strikers within the enclosure, the speed sensing can be performed in a reliable manner which is unaffected by outside disturbances like, falling of material, shifting of pulley & other external impact on mounting assembly which in turn protecting the sensor from being damaged. Moreover, provision of the shaft with rotating wheel enable rotating the striker plates mounted at the other end of the shaft within the enclosure. The enclosure assembly can be mounted anywhere on the rigid support structure of conveyor preferably on the return side idler and far away from the discharge chute thus avoiding any malfunctioning due to chute jamming and material spillage. The operational requirement of the system is that the wheel should be in contact with the conveyor so that linear speed of conveyor is converted to the rotation of wheel and in turn the rotation of strikers inside the enclosure assembly which is sensed by the proximity sensor.

Since mounting of Proximity sensor and its striker was on Snub pulley in previous system, in case of jamming of material and even some times in normal running also material pieces stuck in snub pulley and damaged the proximity sensor which in turn defeated the purpose of ZSS. This damaging of sensor has been protected by the provision of enclosure assembly in new speed sensing system for conveyor according to the present invention. Moreover, the conveyor speed sensing system of the present invention also enable stopping of belt conveyor in case of elongation and slippage due to hot sinter and prevents damaging of belt due to slipping and rubbing.

It is thus possible by way of the present invention to provide a portable conveyor speed sensing system for sensing conveyor speed to protect from speed related damage resulting from broken belts, overloads, or belt slippages, in a reliable manner avoiding chances of damage of sensors, ensuring advantageous application of such system in a variety of conveyor based material transportation operations in industry.

We Claim:

1. A portable conveyor speed sensing system comprising:
an enclosure housing a proximity sensor involving switching based on sensing of a rotatable striker within said housing, said rotation of said rotatable striker operatively connected to a shaft end inside said housing and the other end of the shaft outside the housing connected to a rotating wheel assembly which rotates on contact with the moving conveyor ;
the rotating wheel providing rotary motion to the shaft which in turn rotates the rotatable striker ;
said proximity sensor sensing the rotation of said striker;
a cooperative controller operatively connected to said proximity sensor which generates pulse based on the sensed striker based on which the controller is activated to control the conveyor.

2. A portable conveyor speed sensing system as claimed in claim 1 comprising frame and support structure for mounting the enclosure with said shaft and rotating wheel at any desired location of the conveyor preferably away from the discharge end/chute of the conveyor.

3. A portable conveyor speed sensing system as claimed in anyone of claims 1 or 2 which is adapted for mounting at the return side of the conveyor which is close to one of the return idler but far from the discharge chute.

4. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 3 wherein said proximity sensor comprises a zero speed switch (ZSS) which works on electrical switch and generates output when said striker comes in front of its sensing tips within a specified distance preferably 5 to 10 mm.

5. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 4 wherein a set of strikers are mounted/welded on the non drive part of the rotating shaft.

6. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 5 wherein said enclosure comprises a sealed enclosure isolated from outside disturbances including falling of materials,shifting of pulley and the like.

7. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 6 wherein said striker comprises MS –thin plate as fins and mounted on said shaft inside the enclosure and said proximity sensor senses the metallic fins of rotating striker when it comes near its sensing range and gives electrical signal to the controller.

8. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 7 wherein said controller comprises an electronic controller adapted to sense signal from the sensor and condition it to give switchable output for stopping of conveyor if and when required.

9. A portable conveyor speed sensing system as claimed in anyone of claims 1 to 8 comprising of mounting arrangement comprising a flexible arm for mounting of said enclosure and wheel and its assembly.

10. A conveyor system comprising a portable conveyor speed sensing system as claimed in anyone of claims 1 to 9 comprising:
a conveyor arrangement having a discharge side end and a return side end;
said portable conveyor speed sensing system placed far from said discharge end having discharge chute involving said mounting arrangement whereby the belt motion rotates the rotary wheel which in turn rotates the shaft and the striker housed in said enclosure for sensing by the proximity sensor also housed in said enclosure.

11. A conveyor system as claimed in claim 10 wherein said enclosure and wheel assembly is mounted with respect to the conveyor involving a flexible arm and a fixed arm providing for rigid support to the enclosure and wheel assembly.

12. A conveyor system as claimed in anyone of claims 10 or 11 wherein said enclosure housing the striker and the proximity sensor is mounted at the return side of the conveyor which is close to one of the return idler which is far from the discharge chute.
Dated this the 8th day of August, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)

ABSTRACT

TITLE: A PORTABLE CONVEYOR SPEED SENSING SYSTEM.

The present invention is directed to provide a portable conveyor speed sensing system for detecting conveyor belt speed to avoid speed related damages, wherein proximity sensor assembly along with sensing striker is placed in an enclosure so that the sensor is not affected by external condition of mounting location e.g. material deposition/spillage etc and also not get disturbed by pulley shifting. The enclosure arrangement can be installed anywhere on the conveyor away from the head pulley and the discharge chute and preferably at the return side of the conveyor which is close to one of the return idler but far from discharge chute so that said rotatable striker operatively connected to a shaft end inside said enclosure and the other end of the shaft outside the housing connected to a rotating wheel assembly which rotates on contact with the moving conveyor so as to reliably sense the speed of conveyor avoiding any speed related damages.
(Figure 2)