Claims:We Claim:

1. A system for Hot Spot detection in hot raw material transporting conveyor comprising,

an array of multiple hot spot detectors above moving conveyor spaced to scan entire width of conveyor;
a display and interface unit operatively connected to said hot spot detectors operable at desired temperature range;
said display and interface unit having set up means for configurable threshold temperature ;
comparator means for comparing with sensed temperature for ready identification of possible occurrence of hot spot.

2. A system for Hot Spot detection as claimed in claim 1 comprising air purging unit cooperatively provided with said detectors to keep the detectors clean from dust, smoke and heat in the environment for confirmatory detection.

3. A system as claimed in anyone of claims 1 or 2 comprising,

said array of multiple hot spot detectors selectively deployed above moving conveyor to scan entire width of conveyor for desired reliable and efficient detection of hot spot from low height;
said display and interface unit located in the control room operatively connected to said detector placed above the conveyor adapted to receive and display the temperature value accurately sensed and transmitted by said detectors upto a desired range;
said display and interface unit adapted to be set a configurable threshold temperature and compare with sensed temperature;
alarm means to generate an alarm whenever the threshold limit has been crossed to alert the operator through audio alarm for possible occurrence of hot spot leading to burning of conveyor;
air purging system installed for each detector to keep the detectors clean from dust, smoke and heat in the environment so that reliability of the detection is not decreased.

4. A system as claimed in anyone of claims 1 to 3 wherein said display and interface unit is further able to generate signals corresponding to the threshold limit reached which can be taken into a standard controller like PLC for further control action like opening of water valve etc.

5. A system as claimed in anyone of claim 1 to 4 wherein said multiple detectors comprise IR detectors/sensors.

6. A system as claimed in anyone of claims 1 to 5 wherein the sensor specification sense temperature of specified width from a height of not more than 1 meter.

7. A system as claimed in anyone of claims 1 to 6 wherein said IR sensors used having sensing temperature range of 0-300 degree centigrade and detected spectral response of 8-14 micron, with fast response of 10 msec and accuracy of ±1 % of reading, which is sufficient for the intended application.

8. A system as claimed in anyone of claims 1 to 7 wherein the number of detectors/sensors are selected to cover the entire width of the conveyor.

9. A system as claimed in anyone of claims 1 to 8 comprising temperature setting means for configuring threshold temperature depending on type of conveyor and hot material being transported by it to ensure safe operation free of conveyor burning.

Dated this the 4th day of February, 2017
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)

, Description:FIELD OF THE INVENTION

The present invention relates to a system for hot spot detection in hot material transporting conveyors involving low cost, low height installable, modular type multiple detector/IR pyrometer to cover the width of the conveyor. The invention is directed to a system for accurate Hot Spot Detection based on preset configurable threshold temperature, in Hot Raw Material Transporting Conveyor used for transporting hot material in steel plants avoiding limitations due to height, dust and smoke in shop environment.

BACKGROUND ART

Conventional, industrial camera based hot spot detection systems involves expensive thermal imaging camera having inbuilt capability of powerful optics, robust electronics and accurate detection and analysis software. But, these cameras are expensive and multiple camera needs to be installed to cover the entire width if the width of the belt is large. Other logistics, like sufficient space above the conveyor needs be available so that the camera can be installed at sufficient height above the conveyor belt to cover the entire width of the belt. However, in process industry many times the space above the belt is not available as the belt is covered or space above the belt has to be left free for overhead cranes movement which can interfere with the installed camera. Also, often, the environment where the camera or hot spot detector is installed is marked by presence of heat, dust and smoke. For efficient detection of the hot spots in hot moving conveyor, the camera or hot spot detector should be able to scan and detect the spot anywhere across the width of the conveyor inspite of the presence of dust, heat or smoke.

Drawbacks of existing system:

The main drawback of the aforesaid camera based hot spot detection system is the cost and installation logistics. For accurate detection from large height powerful optics is required to focus the heat energy onto the lens. Also fast response time electronics scanning is required to process the temp as sensed by the pyrometer. Strong visualization software is also required to depict the temperature levels as sensed by thermal camera in pictorial form. All these features add to the cost. Further, if the width of the belt is large then multiple cameras is required which further add to the cost.

Also if a single camera is used to cover the entire width of the conveyor then sufficient height above the conveyor belt should be available. Further, if the camera is installed at height then maintenance becomes an issue as these cameras normally are installed in tough environmental condition of dust, heat and smoke.

Any undetected hot spots may cause conveyor burning which stops the conveyor line leading to production losses besides the replacement cost of the conveyor belt.

Proposed solution:

There has been thus a need in the related field to provide a system for hot spot detection wherein conventional low cost IR Pyrometers would be installed at low height as multiple array of hot spot detectors, having ability to detect temperature ranges above some threshold level so that the entire width of the conveyor is covered with the detection method reliably and efficiently. The second part is to reliably transmit these sensed temperature to display unit where these signals can be displayed and taken further to some central controller like PLC for control action like alarm generation, opening of water valve etc.

OBJECTS OF THE INVENTION

The basic object of the present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor which is low cost yet reliable and efficient to detect hot spot to avoid conveyor burning needing stoppage of plant and related production loss.

A further object of the present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor wherein conventional low cost IR pyrometers would be installed at low height as multiple array of hot spot detectors, having ability to detect temperature ranges above some threshold level so that the entire width of the conveyor is covered with the detection method reliably and efficiently.

A still further object of the present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor wherein space above the belt can be left free for overhead cranes movement as the IR pyrometers are installed at low heights.

A still further object of the present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor wherein modular type multiple hot spot detectors/IR pyrometers are installed to cover the entire width of the conveyor so that number of detector needs to be chosen as per the width of the conveyor.

A still further object of the present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor wherein detectors/IR pyrometers having ability to detect temperature ranges above some threshold level so that the entire width of the conveyor is covered reliably and efficiently.

A still further object of the present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor wherein the system is capable of detecting hot spots anywhere across the width of the hot conveyor belt to work reliably even in dusty, smoke filled and heated environment surrounding hot raw material transporting conveyor.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is directed to a system for Hot Spot detection in hot raw material transporting conveyor comprising,

an array of multiple hot spot detectors/IR pyrometers above moving conveyor spaced to scan entire width of conveyor;
a display and interface unit operatively connected to said hot spot detectors operable at desired temperature range;
said display and interface unit having
set up means for configurable threshold temperature ;
comparator means for comparing with sensed temperature for ready identification of possible occurrence of hot spot.

A further aspect of the present invention is directed to said system for Hot Spot detection comprising air purging unit cooperatively provided with said detectors to keep the detectors clean from dust, smoke and heat in the environment for confirmatory detection.

A still further aspect of the present invention is directed to said system comprising,

said array of multiple hot spot detectors selectively deployed above moving conveyor to scan entire width of conveyor for desired reliable and efficient detection of hot spot from low height;
said display and interface unit located in the control room operatively connected to said detector placed above the conveyor adapted to receive and display the temperature value accurately sensed and transmitted by said detectors upto a desired range;
said display and interface unit adapted to be set a configurable threshold temperature and compare with sensed temperature;
alarm means to generate an alarm whenever the threshold limit has been crossed to alert the operator through audio alarm for possible occurrence of hot spot leading to burning of conveyor;
air purging system installed for each detector to keep the detectors clean from dust, smoke and heat in the environment so that reliability of the detection is not decreased.

A still further aspect of the present invention is directed to said system wherein said display and interface unit is further able to generate signals corresponding to the threshold limit reached which can be taken into a standard controller like PLC for further control action like opening of water valve etc.

Another aspect of the present invention is directed to said system wherein said multiple detectors comprise IR pyrometers/sensors.

Yet another aspect of the present invention is directed to said said system wherein the IR pyrometer specification sense temperature of specified width from a height of not more than 1 meter.

A further aspect of the present invention is directed to said system wherein said IR pyrometers used having sensing temperature range of 0-300 degree centigrade and detected spectral response of 8-14 micron, with fast response of 10 msec and accuracy of ±1 % of reading, which is sufficient for the intended application.

A still further aspect of the present invention is directed to said system wherein the number of IR pyrometers are selected to cover the entire width of the conveyor.

A still further aspect of the present invention is directed to said system comprising temperature setting means for configuring threshold temperature depending on type of conveyor and hot material being transported by it to ensure safe operation free of conveyor burning.

The above and other objects and advantages of the present invention are described hereunder with reference to following accompanying non limiting illustrative drawing.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

Figure 1: illustrates a Block Schematic diagram of developed system for hot spot detection in hot raw material transporting conveyor in accordance with the present invention.
Figure 2: illustrates schematically a 3-D view of developed system for hot spot detection wherein the multiple detectors are covering entire width of hot raw material transporting conveyor from low height.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES

The present invention is directed to provide a system for Hot Spot detection in hot raw material transporting conveyor involving low cost, modular type multiple detectors covering entire width of the conveyor for reliable and efficient detection of hot spot to avoid conveyor burning needing stoppage of plant and related production loss.

As described previously, hot spot detectors are commonly used in process industries where the transportation of hot material over long distances over material conveyor is a necessity. Many a times the raw material being carried over these conveyor have inclusions or spots were heated material is in touch with the conveyor belt for long which leads to fire and burning of the conveyor belt. In absence of any hot spot detector to detect such hot inclusion occurrences, huge loss is incurred due to stoppage of conveyor line and its belt replacement. Conventional camera based hot spot detectors are available in the market but these apart from being quite expensive require special logistics with respect to height and environment for its reliable operation and maintenance. The problem aggravates if the width of the conveyor is large.

Therefore a system is disclosed under the present invention for detecting hot spots involving multiple IR Pyrometers/detectors anywhere across the width of the hot conveyor belt to work reliably even in dusty, smoke filled and heated environment. The system is modular in nature in the way that number of detectors need to be chosen as per the width of the conveyor. The system also displays the sensed temperature and raises an alarm if the sensed temperature crosses the set threshold.

Accompanying Figure 1 illustrates a Block Schematic diagram of developed system for hot spot detection in hot raw material transporting conveyor in accordance with the present invention.

The subject invention concerns a system for detecting hot spot anywhere across the width of the conveyor(1). Instead of single detector, multiple detectors/IR pyrometers (2) installed and low height has been used. The detectors placed above the conveyor in the field can accurately sense and transmit temperature value to its display and interface unit(3) in the control room. The IR pyrometer specification has so been fixed so that each IR pyrometer can accurately sense temperature of specified width from a height of not more than 1 meter. The sensor has been fixed to accurately sense temperature upto 300 degree which is sufficient for the intended application has been used for. Due to harsh environmental condition of dust, heat and smoke, air purging unit(5) has been provided for each detector for accurate detection inspite of harsh environment.

In accordance with an aspect of the invention, a display and interface unit(3) is added to display the sensed individual temperatures. The special feature of this display cum interface unit(3) is the ability to compare the sensed temperature with set threshold temperature. The user can set the desired threshold temperature. The unit generates an alarm in an audio alarm unit (4) operatively connected to said display and interface unit(3) when the sensed temperature crosses the threshold alarm. The display and interface unit(3) has also provision to further carry the detected condition (threshold) to conventional Controller like PLC(not shown) for further control action like opening of water control valve etc.

Thus by way of the present invention, a low cost, multiple detector, low height installable hot spot detection system has been developed for hot material carrying conveyors. The system components has so been selected that the system has been made modular so that for less conveyor width applications, less number of detector shall be employed thus reducing the cost of the system. Each detector has been so chosen that the system can be installed at low height to cover the desired width of the conveyor.

The developed innovation has been subjected to field trial in the sinter carrying conveyors of Sinter Plant of Applicant’s Bokaro Steel Plant. The hot sinter prepared has to be transported to the next feeding plant for further processing. It is that during this time of transportation, the hot spot in the conveyors needs to be detected which may lead to exigencies. Any undetected hot spots may cause conveyor burning which stops the conveyor line leading to production losses besides the replacement cost of the conveyor belt.

The conveyor line due to nature of material being carried has dust, smoke and heat. For any reliable detection system to work in such environment sufficient system for keeping the detector free from such things should be in place. Air purging system has been installed to keep the detector clean so that reliability of the detection is not decreased. Due to frequent movement of overhead cranes, it was a necessity that whatever detection system is installed should be installed in a way that the operation of overhead cranes is not hampered.

In view of above, a novel system has been developed to detect the hot spot reliably anywhere across the width of the conveyor. Instead of going for a single expensive detector to cover the entire width of the conveyor which shall require good height, an array of inexpensive, low height installable detector suitable for the temperature ranges for this application were fixed. Now, even in dusty environment, these detectors can accurately detect hot spot from low height. Series of detector ensures that the entire width is scanned.

As discussed above, the detector sends the detected temperatures to a display and interface unit. The temperature is displayed for the operator to see the temperature as sensed by the individual detectors. In case of abnormality the operator is also able to see from which sensor the corresponding temperature has been displayed. Besides the display, the unit also has the feature to set a threshold temperature. The unit can also generate an alarm whenever the threshold limit has been crossed. This alerts the operator through audio alarm. This threshold temperature is user configurable, in the sense that this temperature can be set as per the application or process requirement. As an additional feature that this unit has is that the signals corresponding to the threshold limit reached can be generated by this unit. This signal can be taken into a standard controller like PLC for further control action like opening of control valve etc.

Best Mode of Working

The developed system is being used to detect hot spots in hot sinter carrying conveyor(1) in steel plant application. An array of three hot detectors(2) have been used (each detector covering width of 500 mm) to cover the entire conveyor width which is 1400 mm. The temperature sensing range of the sensor is upto 300 degree centigrade which is sufficient for the application being used. The sensor specification has so been fixed so that each sensor can accurately sense temperature of specified width from a height of not more than 1 meter. The system accurately detects hot spots as per configurable threshold and has been configured to raise alarm if the temperature exceeds the set temperature. The detailed system architecture is shown in accompanying Figure 1.

Accompanying Figure 2 further illustrates schematically a 3-D view of the developed system for hot spot detection according to the invention wherein the multiple detectors are advantageously covering entire width of hot raw material transporting conveyor from low height, preferably less than 1 meter, for effective detection of hot spot at any location across the width of conveyor.

The hot spot detection system according to present invention thus having the following novel features for which protection is being sought under the patent application.
i. Multiple detectors has been used to cover the entire width of the conveyor.
ii. Designed for low height installation.
iii. Sensing temperature range 0-300 degree centigrade. Detected spectral response of 8-14 micron.
iv. Air purging jackets provided for reliable operation even in dusty environment.
v. Fast response of 10 msec and accuracy of ±1 % of reading.
vi. Provision of connecting to standard controller.

Although the foregoing description of the present invention has been shown and described with reference to particular applications thereof, it has been presented for purposes of illustration and is not intended to be exhaustive or to limit the invention to the particular applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular application was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various applications and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.