DESC:TECHNICAL FIELD
[0001] The present disclosure generally relates to the field of factory automation. In particular, it pertains to equipment used for monitoring of industrial processes. More specifically, the present disclosure pertains to a system and device for withdrawing such monitoring means from adverse environment under emergency conditions so as to avoid damage to monitoring means.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Industrial processes often require one or other kind of furnaces such as industrial incinerator for incinerating wastes, a melting furnace for steel or other metal/metal alloy making processes, a blast furnace for steel making, a gas furnace for melting glass, a cement kiln, a boiler of a power plant, a pottery furnace etc. are some examples of use of furnaces in industry.
[0004] A common requirement in most of such applications is to monitor the process inside the furnace by measurement of operating parameters by means of probes or/and visual inspection of inside contents and/or inside processes. In certain cases where furnaces are run continuously without break such as boilers or blast furnaces, it may be necessary to observe the physical condition of interiors so that maintenance breaks are taken only when absolutely necessary.
[0005] While measurement of operating parameters is done by placing sensors/probes through the wall of furnace, conventional methods of observing inside of an industrial furnace is to peek through a window formed in the wall. The window is provided with door to close the opening when not in use and may or may not have a glass covering to prevent escape of heat/ingress of atmospheric air when in use.
[0006] In view of obvious disadvantages and inefficiencies of conventional method of observing inside of a furnace, use of a camera that provides better and continuous monitoring has come to be preferred method. Any monitoring device, be it a camera for visual inspection or a probe/sensor to record/measure process parameters, is to be protected from harsh environment of the furnace such as high temperature and/or presence of corrosive gases. Normally cooling air/water supply is made/circulated to protect monitoring equipment from their adverse effects. However, in situations where such means fail, the monitoring equipment placed inside the furnace is exposed to hazardous situation that can lead to expensive damage.
[0007] System and apparatus are employed to withdraw monitoring equipment out of furnace under such circumstances so that damage is avoided. Such system and apparatus generally detect failures and actuate withdrawal means to withdraw the equipment and may also comprise means to close the opening to prevent loss of heat or ingress of atmospheric air.
[0008] The existing systems suffer from disadvantage of dependence on electrical control circuits, more so in third world countries where power failure are endemic and dependence on electrical means for such a sensitive application may not be advisable. There is therefore need for a more efficient and dependable system to withdraw sensitive and expensive equipment out of harsh environment of a furnace to protect them from exposure to hazardous situations.
[0009] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0010] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0011] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0012] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0013] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0014] An object of present disclosure is to overcome problems associated with existing methods of automatically retracting/retrieving sensitive equipment out of furnace on occurrence of undesirable events that create hazardous situation for the equipment.
[0015] Another object of present disclosure is to provide method and apparatus that closes the opening in the furnace wall after the equipment has been withdrawn.
[0016] Another object of present disclosure is to provide a method that closes the opening in the furnace wall after predefined time delay to avoid damage to the equipment during closure of the opening.
[0017] Another object of present disclosure is to provide method and apparatusthat does not depend on electrical means for controlling the operation of the withdrawal apparatus.
[0018] Another object of present disclosure is to provide method and apparatus that uses pneumatic command and pneumatic logic
[0019] Another object of present disclosure is to provide an apparatus and method that can retrieve the equipment deployed in furnace in an inclined position overcoming the gravitational forces acting against the withdrawal action.

SUMMARY
[0020] Aspects of present disclosure relate to automatic withdrawal of sensitive equipment out of hostile environment on occurrence of undesirable events that create hazardous situation for the equipment. In particular, it relates to retracting a camera or a probe out of a furnace to prevent its damage from high furnace temperature upon failure of cooling air supply that keeps the equipment protected from high furnace temperature.
[0021] In an aspect, the disclosure also provides for method and means to close the opening/aperture in the furnace to prevent loss of heat from the furnace and/or ingress of atmospheric air that may affect furnace environment. In an aspect a baffle mechanism is provided to close the opening/aperture in the furnace.
[0022] In an aspect of the disclosure, the method and apparatus do not depend on electrical command and/or means to carry out retraction of the equipment and operating the baffle mechanism wherein both command and means are purely pneumatic.
[0023] In another aspect, the present disclosure provides method and apparatus that senses drop in pneumatic pressure and actuates pneumatic logic to activate equipment retraction means and baffle mechanism.
[0024] In another aspect, the present disclosure provides equipment retraction means and baffle actuation means that are also pneumatic and draw compressed air supply from a storage reservoir provided for this purpose.
[0025] In yet another aspect of the present disclosure, method and apparatus provide a time delay in closure of aperture to prevent any likelihood of damage to the retracting equipment from the door/baffle of the aperture. In an aspect, the time delay in the closure action is also executed by means of pneumatic logic.
[0026] Thus, the present disclosure provides a method and apparatus for automatic withdrawal of sensitive equipment such as a camera or a probe/sensor out of a furnace to protect it from damage from high temperature in the event of failure of cooling air supply, wherein the method and apparatus does not depend on electric command, control or means and instead uses purely pneumatic command, control or means thus insulating the withdrawal process from likely parallel electric failure.
[0027] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components

BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0029] FIG. 1 illustrates an exemplary perspective view of the camera withdrawal apparatus in accordance with embodiments of the present disclosure.
[0030] FIG. 2 illustrates an exemplary schematic diagram of configurations of the camera withdrawal equipment in accordance with embodiments of the present disclosure.
[0031] FIG. 3 illustrates an exemplary schematic diagram of configurations of end plate assembly in accordance with embodiments of the present disclosure.
[0032] FIG. 4(a) illustrates an exemplary isometric view of end plate assembly with aperture in open condition in accordance with embodiments of the present disclosure.
[0033] FIG. 4(b) illustrates an exemplary isometric view of end plate assembly with aperture in closed condition in accordance with embodiments of the present disclosure.
[0034] FIG. 5 illustrates an exemplary line diagram of pneumatic circuit of withdrawal apparatus in accordance with embodiments of the present disclosure.
[0035] FIG. 6 illustrates an exemplary layout of air filtration system in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0036] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0037] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0038] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0039] Embodiments described herein pertain to a method and apparatus for automatic withdrawal of a camera deployed in a furnace upon failure of cooling air supply using purely pneumatic command, logic and means without dependence on electrical command, logic and means. In an embodiment, the disclosure also provides for closure of the aperture/opening through which the camera is deployed in the furnace, after the withdrawal there is a time delay so that the withdrawing camera equipment is not damaged by the closing door/flap.
[0040] It is to be understood that though the embodiments of the disclosure have been explained with reference to withdrawal of a camera from a furnace, the method and apparatus of the present disclosure can be equally applied to any other sensitive equipment like a probe or a sensor etc. that may need to be withdrawn from harsh environment under emergency conditions such as failure of cooling air supply. Further, the term furnace is meant to include all its variants such as an industrial incinerator for incinerating wastes, a melting furnace for steel or other metal/metal alloy making processes, a blast furnace for steel making, a gas furnace for melting glass, a cement kiln, a boiler of a power plant, a pottery furnace and all other such furnaces.
[0041] FIG. 1 illustrates an exemplary perspective view of the camera withdrawal apparatus 100 in accordance with embodiments of the present disclosure. Depicted therein is camera 102 that can include a camera body 104 and lens tube 106(also called camera probe hereinafter). The camera 102 can be slidably mounted on a set of guide rails 108 whose distal end can be configured with an end plate assembly 110. The end plate assembly 110 can be configured for mounting on furnace wall so that an opening/aperture (not seen as covered by flap/cover 114) in the end plate assembly 110 provides access to inside of the furnace. The end plate assembly 110 can include a baffle assembly 112 that can include a flap/cover 114 to close the opening. The apparatus 100 can additionally have a pneumatic cylinder (not shown in FIG.1) to move the camera 102 along the guide rails 108.
[0042] In an embodiment, the pneumatic cylinder used to move the camera 102 along the guide rails 108 can be a double acting pneumatic cylinder so that it can both deploy and retract the camera 102 depending on which side of its piston gets compressed air supply. Thus by directing the compressed air to one side of the pneumatic cylinder, the camera 102 can be deployed inside the furnace and on the other hand by directing the compressed air supply to the other side, the camera can be retracted from its deployed position.
[0043] FIG.1 depicts the apparatus 100 with camera in retracted condition (also referred to as initial position hereinafter) wherein the lens tube/camera probe 106 is out of the aperture and the aperture is closed by flap/cover 114. In operation the aperture shall be open and camera 102 in axially advanced position (also referred to as deployed position hereinafter) towards end plate assembly 110 with camera probe 106 inside the furnace through the aperture. In this condition the camera probe 106 is supplied with cooling air to protect it from high temperature of the furnace. In the event of failure of cooling air supply and to protect the camera probe 106 from high temperature of the furnace, pneumatic cylinder can act to retract the camera 102 back along the guide rails 108 till the camera probe 106 is fully out of the aperture. After some time delay (from the moment when the pneumatic cylinder starts to retract the camera 102) the baffle assembly 112 can be actuated to close the aperture by means of flap/cover 114. In an embodiment the time delay can correspond to time that the apparatus takes to retract the camera 102 fully such that the camera probe 106 does not come in path of the closing flap/cover 114 which can otherwise damage the camera probe 106.
[0044] In an embodiment the retraction of the camera 102 and closure of the aperture can take place automatically on pneumatic failure i.e. pressure of compressed air supply going below a predefined value. In another embodiment similar automatic retraction and closure action can take place in the event of electric failure and a combination of electric and pneumatic failure.
[0045] In yet another embodiment, it is possible that the camera 102 is mounted on the furnace at an angle looking downward towards the bottom of the furnace to meet the operational and functional requirements of proper monitoring the furnace condition. Under such a condition, due to its weight and gravitational pull, camera 102 shall have a tendency to move forward (deployed condition). Therefore there is a need to not only retract the camera back to initial position against the gravitational pull but also stopping it at the initial position for certain time interval. This time interval can be increased or decreased as per the requirement and it can go up to years. The disclosed apparatus takes care of such eventuality as would be apparent from subsequent description.
[0046] FIG. 2 illustrates an exemplary schematic diagram 200 of configurations of the camera withdrawal equipment 100 in accordance with embodiments of the present disclosure. The exemplary schematic diagram 200 depicts camera 102 having a camera body 104 and lens tube/probe 106, slidably mounted on a set of guide rails 108 by means of a frame 202. A pneumatic cylinder 204 is configured parallel to guide rails 108 and can move the camera 102 along the axis of guide rails 108. Also depicted is the end plate assembly 110 configured on one end of the guide rails 108and further configured with a baffle assembly 112.There can be a second end plate 206 configured at other end of guide rails 108 to make a rigid mounting structure.
[0047] In an embodiment, the camera withdrawal equipment 100 can be configured to place camera 102 in an inclined position looking downward towards the bottom of the furnace. This can be achieved by placing the end plate assembly 110 at an angle to the longitudinal axis of the guide rails 108.In an alternate embodiment the mounting face of the wall of the furnace can be inclined at 45 degrees from vertical in which case no change in the arrangement of the end plate assembly 110 and the guide rails 108 would be necessary. In a preferred embodiment the camera angle can be up to 45 degrees from horizontal.
[0048] FIG. 3 illustrates an exemplary schematic diagram 300 of configurations of the end plate assembly 110 in accordance with embodiments of the present disclosure. In an embodiment, the end plate assembly 110 can include end plate 302 configured with plurality of holes 308 to help mount the end plate assembly 110 on the wall of the furnace. There can be an aperture 304 for access to the interior of the furnace by the camera probe 106, the aperture 304 can be configured with a flange 306 to provide proper seating/sealing surface to the flap/cover 114 to properly close the aperture 304. Further, the end plate assembly 110 can have a baffle assembly 112 suitably fixed on the end plate 302. Baffle assembly 112 can include a shaft 310 and the flap/cover 114 can be appropriately configured on the shaft 310 such that rotation of the shaft 310 in one or other direction results in flap/cover 114 either closing or opening the aperture 306.
[0049] In an embodiment, the baffle assembly 112 can incorporate means to pneumatically rotate the shaft 310 in one or other direction depending on requirement. In an exemplary embodiment, these means can be a rotary mechanism in which a rotary actuator is assembled with a shaft 310 and a flap 114.Alternately it can be a pneumatic cylinder coupled to a rack and pinion arrangement to convert linear motion of the pneumatic cylinder to rotational motion of the shaft 310.
[0050] In an embodiment the baffle assembly 112 that operates to close the aperture is controlled by pneumatic logic such that it closes the aperture after a certain time delay. In another aspect the time delay is also controlled purely by pneumatic logic and no electrical, PLC or electronic is involved in the delaying the operation of the baffle 112. As stated earlier time delay can correspond to time that the apparatus takes to retract the camera 102 fully such that the camera probe 106 does not come in path of the closing flap/cover 114 which can otherwise damage the camera probe 106. Thus the built in delay in operating the baffle assembly 112 to close the aperture prevents the possible damage to the retracting camera probe 106 by the closing flap 114. Dependence on purely pneumatic logic ensure that the equipment works in accordance with its intended function even in the eventuality of complete blackout in the plant
[0051] FIG. 4(a) and FIG. 4(b) illustrate exemplary isometric views400 and 450 of the end plate assembly 110 with aperture in open condition and with aperture in closed condition respectively in accordance with embodiments of the present disclosure.
[0052] FIG. 5 illustrates an exemplary line diagram 500 of pneumatic circuit of withdrawal apparatus in accordance with embodiments of the present disclosure. The pneumatic circuit can be broadly divided in two parts first being air filtration system 502 and other retract control system 504. Compressed air supply can be continuously received at air intake 506 at a minimum pressure of 5.5 bar and after going through air filtration system 502 can be sent for camera cooling through camera cooling outlet 508. Another outlet 510 supplies compressed air to retract control system 504.
[0053] FIG. 6 illustrates an exemplary lay out 600 of air filtration system 502 in accordance with an embodiment of the present disclosure. The air filtration system 502 can comprise of a filter 602 and an oil removal filter 604. The system 502 can further include a regulator 606 and a pressure switch608. Supply to retract control system 504 can be provided through outlet 510 and for camera cooling through second outlet 508. In an embodiment the pressure switch 608 can detect loss of pressure in compressed air supply and act to cause the camera 102 to be retracted from the furnace so as to avoid damage in absence of adequate cooling air supply (details provided in subsequent paragraphs).
[0054] In an embodiment and as illustrated in FIG. 5, retract control system 504 can include a pressure regulator valve 512 to regulate the incoming air pressure, a three way ball valve 514, a check valve 516, a reservoir 518 to store compressed air to meet the requirement of compressed air to operate the retraction mechanism in the event of failure of compressed air supply. The retract control system 504 can additionally have a pilot operated check valve 520, a 5/2 way valve 522 (also referred to as pilot operated valve 522 hereinafter) and a solenoid control valve 524 (referred to as solenoid valve 524 hereinafter). The output from the retract control system 504 can be fed to cylinder that retracts the camera 102 out of the aperture and buffer actuating means 112.
[0055] In an embodiment the retract control system 504 receives filtered compressed air supply through pipe 510 from air filtration system 502 which can be configured to filter incoming air up to 5 microns. Filtered air is received at regulator 512from where it can go to the 3 way ball valve 514. The 3 way ball valve 514 can be configured to release trapped air when required. After 3 way ball valve 514 the compressed air is bifurcated - one towards the check valve 516and other to the solenoid valve 524. The check valve 516 is configured before the reservoir 518 and can function as non-return valve such that the reservoir 518 can get compressed air supply through check valve 516 valve as long as supply pressure is adequate but act to isolate reservoir 518 from supply line to prevent loss of pressure in case line pressure falls below the air pressure in the reservoir 518.
[0056] In an embodiment, reservoir 518 is configured to store adequate supply of compressed air to meet the requirement of camera retracting mechanism and buffer assembly 112. In an aspect the reservoir 518 can be tapped for air supply to the check valve 520 and thereafter to the inlet of the pilot operated valve 522. The pilot operated valve 522 can operate to allow air to pass through when the air pressure at its pilot port is above a preset threshold (for example 2 bar)and closes/returns back through a spring action to block the air passage when the air pressure at the pilot port is below the preset threshold.
[0057] In an embodiment, the solenoid valve 524 that receives air supply through second of the bifurcated branches from the 3 way ball valve 514 can be configured to allow the air to pass through it when a rated voltage is applied to it and block the air passage when there is no voltage. In an embodiment the pilot port of the pilot operated valve 522 gets air supply from output side of the solenoid valve 524. Therefore in an embodiment, when a rated voltage is applied to the solenoid valve 524, compressed air is allowed to travel past solenoid valve 524 and reach the pilot port of the pilot operated valve 522 thus allowing the air to pass through the pilot operated valve 522and reach pneumatic cylinder of the retracting mechanism so as to move camera 102 in forward direction and deploy it in the furnace. In an alternate scenario when there is no voltage applied to the solenoid valve 524, compressed air is not allowed to travel past solenoid valve 524 and in absence of air pressure at the pilot port of the pilot operated valve 522, no air would be allowed to pass through the pilot operated valve 522.
[0058] In another embodiment the pilot operated valve 522 can incorporate two air passages such that compressed air that is allowed to pass through the first passage can operate the pneumatic cylinder in forward direction (to deploy the camera 102 inside the furnace) and compressed air that is allowed to pass through the second passage can operate the pneumatic cylinder in backward direction (to retract the camera 102 from its deployed position the furnace). Furthermore the two passages are configured to open/close in reverse to each other i.e. when the pilot port is supplied with air pressure, the first passage opens while the second passage exhausts the air to atmosphere; and on the other hand when there is no air pressure at the pilot port, the first passage exhausts the air to atmosphere and the second passage opens to supply the compressed air. In an aspect first passage is connected to air cylinder to move the camera 102 in forward direction and the second passage is connected to air cylinder to move the camera 102 in backward direction.
[0059] In another aspect the compressed air from the first and the second passages is also supplied to the baffle assembly 112 to actuate the baffle thus enabling operation of the baffle in tandem with the camera position.
[0060] In another embodiment the pilot operated valve 522 gets its compressed air supply (for feeding the two passages) from the reservoir 518 so that even in the event of inadequate air pressure, the retraction system can retract the camera 102 out of the furnace and close the baffle.
[0061] In another embodiment the pressure switch 608 of the air filtration system 502 can be configured in series with the voltage supply connection to the solenoid valve 524. Therefore whenever pressure of the compressed air supply to camera cooling system falls below a preset value, the pressure switch 608 can operate to cut off voltage supply to the solenoid valve 524 causing solenoid valve 524 to block the air supply to the pilot port of the pilot operated valve 522 which in turn can actuate to retract the camera 102 out of the furnace. Thus the retract control system 504 can activate the camera withdrawal in adverse situations such as electric failure and/or inadequate supply of cooling air to the camera 102. In an aspect, if the need arises to retract the camera 102 out of furnace even without occurrence of one of the two adverse occurrences the same can be done by switching off the voltage supply to the solenoid valve 524.
[0062] In an embodiment compressed air supply to baffle assembly112 can incorporate a time delay mechanism 526 to introduce an element of delay in closure of the baffle after the camera 102 has been withdrawn from the furnace. The element of delay in closing of baffles can prevent any possible damage to the camera probe 106 from the closing baffle. In an embodiment the delay mechanism 526 works on purely pneumatic logic and is not dependent on electrical or mechanical means.
[0063] In an embodiment the retract control system 504 can be so designed as to be able to retract camera even from an inclined position against the forces of gravity and thereafter hold in initial position for a desired time period. Storage of adequate compressed air in reservoir 518 at operating pressure of 6 bar ensures that no difficulty is faced in retracting the camera against the gravitational forces. In an embodiment the retracting mechanism incorporates a double acting pneumatic cylinder that retract camera 102 based on air supply from the reservoir 518. Since the pilot operated valve 522 gets compressed air supply from the reservoir 518 through the pilot operated check valve 520, loss of pressure in the pneumatic cylinder is prevented even if pressure in the reservoir 518 drops with time. Thus the retract control system 504 can hold the camera against force of gravity for a desired long time period.
[0064] Thus the embodiments of the present disclosure provide a method and apparatus for automatic withdrawal of a camera deployed in a furnace upon failure of cooling air supply using purely pneumatic command, logic and means without dependence on electrical command, logic and means.
[0065] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0066] The present disclosure overcomes the problems associated with existing methods of automatically retracting/retrieving sensitive equipment out of furnace on occurrence of undesirable events that create hazardous situation for the equipment.
[0067] The present disclosure provides a method and an apparatus that closes the opening in the furnace wall after the equipment has been withdrawn.
[0068] The present disclosure provides a method that closes the opening in the furnace wall after predefined time delay to avoid damage to the equipment during closure of the opening.
[0069] The present disclosure provides a method and an apparatus that does not depend on electrical means for controlling the operation of the withdrawal apparatus.
[0070] The present disclosure provides a method and an apparatus that uses pneumatic command and pneumatic logic for operation of the withdrawal apparatus.
[0071] The present disclosure provides an apparatus and a method that can retrieve the equipment deployed in furnace in an inclined position thus overcoming the gravitational forces acting against the withdrawal action with the help of a reservoir.
,CLAIMS:1. An apparatus to automatically withdraw an equipment out of a furnace on failure of cooling air supply or failure of electrical supply, the apparatus comprising:
a pneumatic cylinder configured to deploy and retract the equipment into or out of the furnace through an aperture;
a baffle assembly configured to open and close the aperture; wherein the means to open and close the aperture are pneumatically operated; and
a retract control system configured to detect failure of cooling air supply to the equipment and based on a pneumatic logic, actuate the pneumatic cylinder to withdraw the equipment out of the furnace using a reservoir and close the aperture.
2. The apparatus of claim 1, wherein the detection of the failure of cooling air supply to the equipment is based on pressure of the cooling air supply to the equipment.
3. The apparatus of claim 1, wherein the apparatus is further configured to detect electric failure and actuate the pneumatic cylinder to retract the equipment out of the furnace and close the aperture.
4. The apparatus of claim 1, wherein the pneumatic cylinder is a double acting pneumatic cylinder.
5. The apparatus of claim 1, wherein the retract control system incorporates a pilot operated valve comprising a first air passage and a second air passage wherein air flow from input port of the pilot operated valve is allowed through the first passage and the second passage is connected to atmosphere when air pressure at pilot port of the pilot operated valve is above a preset threshold; and the air flow from the input port of the pilot operated valve is allowed through the second passage and the first passage is connected to the atmosphere when air pressure at the pilot port of the pilot operated valve is below the preset threshold, and wherein the first passage is configured to supply air to deploy the equipment and open the baffle; and the second passage is configured to supply air to retract the equipment and close the baffle.
6. The apparatus of claim 5, wherein the retract control system further incorporates a solenoid valve configured in the air passage to the port of the pilot operated valve, wherein the solenoid valve is configured to allow compressed air to reach the pilot port of the pilot operated valve when a rated voltage is applied to the solenoid valve but blocking the compressed air from reaching the pilot port of the pilot operated valve when the rated voltage is not applied to the solenoid valve.
7. The apparatus of claim 5, wherein the reservoir stores compressed air to meet requirement of the pneumatic cylinder to retract the equipment out of the furnace and the input port of the pilot operated valve gets its air supply from the reservoir.
8. The apparatus of claim 5, wherein the apparatus further incorporates a pressure switch in series with voltage supply to the solenoid valve, wherein the pressure switch is configured to detect pressure of the compressed air supply for camera cooling and disconnect the voltage supply to the solenoid valve when the air pressure falls below a preset value.
9. The apparatus of claim 1, wherein the baffle closes with a time delay after retraction of the camera starts.
10. The apparatus of claim 9, wherein the time delay in closing the baffle is achieved by a time delay mechanism, and wherein the time delay mechanism works based on pneumatic logic.