FIELD OF THE DISCLOSURE
The present application generally relates to the field of industrial equipment. Particularly, but not exclusively, the present disclosure relates to the construction and arrangement of fired heaters. More particularly, the present disclosure discloses an arrangement for a fired heater explosion door that is visibly leak-tight.
BACKGROUND OF THE DISCLOSURE
The information in this section merely provides background information related to the present disclosure and may not constitute prior art(s).
Fired heaters play a crucial role in heating process fluids in most industrial applications. Flue gases are produced in the fired heater due to the burning of the fuel in the burners mounted in the radiant section. These flue gases, after heat exchange in the fired heater, are exhausted to the atmosphere through a vertical stack after the convection section. A fired heater has restricted and limited entry and exit points for air and flue gases. The air and fuel enter through the burners and the products of combustion; termed as flue gas, exit through the stack. The fired heater is operated at a nominal negative draft due to the stack (chimney) effect. The flue gases inside the fired heater being hot, are less dense and hence rise, creating a marginal vacuum that tends to draw air into the fired heater through the burner inlets. The fired heater is not configured to withstand abnormal internal pressure build-up. To prevent sudden accidental abnormal internal pressure build-up, all fired heaters are normally provided with some logic arrangement that cuts off the fuel and stops the fired heater in case the pressure builds up beyond a threshold value. But these interlocks, although helpful in mitigating subsequent damage, are unable to altogether prevent an explosion in case of sudden ignition of a large volume of unburnt fuel during poor lighting attempt of the fired heater or more dangerously in case of tube leak resulting in ignition of the leaking combustible process fluid. Sudden accidental or emergency

abnormal internal pressure build-up can cause mechanical damage to the fired heater internals like coils (which carry process fluid), refractory (especially ceramic fiber type refractory) and in severe cases the heater casing and structure as well.
Fired heaters are therefore usually provided with explosion doors which help to relieve the pressure in case of sudden accidental or emergency internal pressure build-up. Generally, as shown in Fig. 1, a typical mechanical type of explosion door (1) has a plurality of hinges (2) on its top side and is oriented slightly inclined to a fired heater casing (3) so that it remains closed under its own weight. The explosion door (1) comprises a door handle (4) to provide support while lifting the explosion door (1) manually. Gaskets (5) are provided at a seating area of the explosion door (1) around a door frame (6). Fig. 1(a) shows the front view of the explosion door known in the prior art. Fig. 1 (b) shows the sectional view of the explosion door about axis A-A. In case of excessive pressure build-up, the explosion door (1) swings open due to the internal pressure and relieves the sudden pressure buildup inside the fired heater. In severe accident cases, there are known instances where the steel explosion door covers got dislodged along with the hinges (2) and got thrown away several meters due to the impact of the explosion and hence mitigated the damage to heater internals in the process.
Moreover, these explosion doors are also a source of entry of tramp air inside the fired heater, as the explosion doors cannot be kept under tightened conditions for proper sealing, and because the fired heater always operates under mild negative pressure. Tramp air in the fired heaters is a big concern and is often seen as a cause for many fired heater accidents, be it excessive NOx emissions, reduced thermal efficiency, or the fired heater capacity shortfall. This ingress of unwanted tramp air through the explosion door (located just below the convection section) in the fired heater also affects the reading of analyzers located at the convection section bottom in the fired heater, thus sending confusing signals to the operators.

Accordingly, there is a need in the art to provide an arrangement that prevents any leakage of tramp air into the fired heater through the explosion door but does not interfere with the normal functioning of the explosion door. The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the prior art.
SUMMARY OF THE DISCLOSURE
The present disclosure overcomes one or more drawbacks of conventional arrangements as described in the prior art and provides additional advantages through an arrangement as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure, an explosion door arrangement for a fired heater is disclosed. The explosion door arrangement comprises a door frame defining a door opening, an explosion door configured to cover the door opening, a sealing cover configured to cover the explosion door and prevent leakage of tramp air into the fired heater and a sealing cover mounting mechanism configured to mount the sealing cover over the explosion door. The sealing cover is configured to rupture when the pressure in the heater increases more than a minimum predetermined threshold value and allows the explosion door to swing open and relieve the pressure inside the fired heater.
In an embodiment of the present disclosure, the explosion door arrangement comprises a plurality of hinges to pivotally attach the explosion door to the door frame.
In an embodiment of the present disclosure, the sealing cover mounting mechanism comprises a sealing cover mounting frame configured with either the

door frame or a fired heater casing around the periphery of the explosion door arrangement.
In an embodiment of the present disclosure, the sealing cover mounting mechanism comprises a plurality of bolts that enter corresponding recesses defined in the sealing cover mounting frame.
In an embodiment of the present disclosure, the sealing cover replacement is facilitated through a plurality of hinges at one edge of the sealing cover mounting frame.
In an embodiment of the present disclosure, the sealing cover is a rectangular metal foil having a thickness in the range of 0.005 - 0.5 mm.
In an embodiment of the present disclosure, the explosion door arrangement comprises a gasket configured to prevent leakage of tramp air at bolting locations beneath the sealing cover.
In an embodiment of the present disclosure, an undamaged sealing cover is a visual indicator that the explosion door arrangement is leak-tight.
In an embodiment of the present disclosure, a degree of damage or rupture of the sealing cover is a visual indicator of a degree of severity of an over pressure incident and is helpful in identification of the associated risks with the over pressure incident.
In an embodiment of the present disclosure, the explosion door arrangement being mounted on a fired heater or any large, pressurized vessel wherein the risk of over pressure needs to be addressed is disclosed.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features

described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF DRAWINGS
The novel features and characteristics of the disclosure are set forth in the description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
FIG. 1 illustrates a schematic view of an existing explosion door arrangement, in accordance with the prior art.
FIG. 2 illustrates a schematic view of an explosion door arrangement that includes a new sealing cover and a sealing cover mounting mechanism that can be mounted on an existing explosion door, according to an embodiment of the present disclosure.
FIG. 3 illustrates a schematic view of an explosion door arrangement that includes new explosion door a sealing cover and a sealing cover mounting mechanism, according to an embodiment of the present disclosure.
FIG. 4 illustrates a schematic view of the sealing cover and its bolting / gasket details which is common for both Fig. 2 and Fig. 3, according to an embodiment of the present disclosure.

FIG. 5 illustrates a damage pattern of the sealing cover under uniform pressure of -189 KN/m2, according to an embodiment of the present disclosure for Failure mode A.
FIG. 6 illustrates a displacement profile of the sealing cover under uniform pressure of- 18.8 KN/m2, according to an embodiment of the present disclosure for Failure mode B.
FIG. 7 illustrates a Von-mises stress profile of the sealing cover under uniform pressure of- 18.8 KN/m2, according to an embodiment of the present disclosure for Failure mode B.
FIG. 8 illustrates a crack formation in the sealing cover under uniform pressure of - 18.8 KN/m2, according to an embodiment of the present disclosure for Failure mode B.
Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
DETAILED DESCRIPTION
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the disclosure as defined by the appended claims.

Before describing in detail embodiments, it may be observed that the novelty and inventive step that are in accordance with the present disclosure resides in a visibly leak-tight arrangement for a fired heater explosion door. It is to be noted that a person skilled in art can be motivated from the present disclosure and modify the various constructions of the proposed invention. However, such modification should be construed within the scope and spirit of the disclosure. Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible same numerals will be used to refer to the same or like parts.
According to an embodiment of the present disclosure, as shown in Figs. 2-4, an explosion door arrangement (11) is provided for a fired heater. The explosion door arrangement (11) comprises a door frame (12) defining a door opening, an explosion door (13) configured to cover the door opening, a sealing cover (14) configured to cover the explosion door (13) and prevent leakage of tramp air into the fired heater and a sealing cover mounting mechanism configured to mount the sealing cover (14) over the explosion door (13). The proposed arrangement has a

simple construction wherein zero leakage of tramp air into the fired heater through the explosion door (13) can be ensured. The sealing cover (14) is configured to damage or rupture when a pressure inside the fired heater increases more than a minimum predetermined threshold value and allow the explosion door (13) to swing open and relieve the pressure inside the fired heater. In the proposed arrangement, the explosion door (13) is covered as per the currently prevalent designs (as shown in Fig. 2) and would also be suitable for another alternate / new designs (as shown in Fig. 3) of the explosion doors.
In more detail, the explosion door (13) is preferably rectangular in configuration for covering a rectangular opening but may be circular, or of any other equivalent shape. The explosion door arrangement (11) comprises a plurality of hinges (15) to pivotally attach the explosion door (13) to the door frame (12). In an embodiment, the sealing cover mounting mechanism comprises a sealing cover mounting frame (16) configured with either the door frame (12) or a fired heater casing (17) around the periphery of the explosion door (13). In an embodiment, the sealing cover mounting frame (16) may be configured to have two components, one is a seating base frame (22), and another is a closing frame (23) between which a gasket (19) and the sealing cover (14) is pressed as shown in Fig. 4. These two components of the sealing cover mounting frame (16) are connected through the plurality of hinge (21) at one of their edges to facilitate the replacement of the damaged or ruptured sealing cover (14). In an embodiment, any other replacement mechanism of the sealing cover (14) can also be used. In another embodiment, the sealing cover mounting mechanism configured to mount the sealing cover (14) over the explosion door (13) can be selected by any other method known in the art such as pasting, gluing, taping, sewing, threading, partial/full bolting on the periphery, hard pressing, welding/stitch welding or any other method to make system leak proof. All such modifications should be construed within the scope of the present disclosure.

The explosion door (13) is covered with the sealing cover (14) that covers the explosion door (13) completely with the help of the sealing cover mounting mechanism. The sealing cover mounting mechanism comprises a plurality of bolts (18) that enter corresponding recesses defined in the sealing cover mounting frame (16). In an embodiment, the sealing cover (14) has a varying thickness and can be made from a group of materials such as stainless steel, polymer sheet, polythene, Aluminium, carbon steel, glass, or any other material suitable for the current arrangement with any suitable thickness. In an embodiment, the thickness of the sealing cover (14) can be in the range of 0.005 - 0.5 mm for the foil. However, the thickness may vary depending on different applications so as to ensure leak tightness, outdoor service, but is weak enough so that it will tear/shatter from the impact of the opening of the explosion door.
As shown in Figs. 2 and 3, the sealing cover mounting frame (16) is configured with either the door frame (12) or a fired heater casing (17) around the periphery of the explosion door (13). In a preferred embodiment, the sealing cover mounting frame (16) is welded with the door frame (12) / fired heater casing (17). The sealing cover (14) is bolted to the sealing cover mounting frame (16) vide a leak-tight strip joint. In an embodiment, a stiffener plate (20) may also be provided which is configured to support the welded joint between the sealing cover mounting frame (16) with the door frame (12) / fired heater casing (17). The explosion door arrangement (11) further comprises a gasket (19) configured to prevent leakage at bolting locations beneath the sealing cover (14). In an embodiment, a tape/rope gasket or any other type of gasket may also be used to prevent the leakage of the tramp air at the bolting locations beneath the sealing cover (14). The explosion door arrangement (11) thereby is a leak-tight system as no tramp air ingress into the fired heater is possible through the sealing cover (14) placed over the explosion door (13).
In case of a sudden accidental pressure build-up, the explosion door (13) shall tear the sealing cover and swing open relieving the pressure. The small swinging of

the door on account of pressure build-up that fails to tear the sealing cover (14) is a visual indicator that the explosion door arrangement (11) is leak-tight. Further, in case of ruptured or damaged sealing cover (14), a degree of damage of the sealing cover (loosening, small tear, slight damage, or complete bursting, etc.) shall give a clear visual indication of the degree of severity of the overpressure incident. This can be helpful in the identification of the associated risks with overpressure and based on the degree of severity, the troubleshooting can be carried out. Furthermore, an observer can conclude that tearing of the sealing cover (14) is reliable evidence that there has been an overpressure incident and that should possibly warrant an investigation, and the severity of the tear would give an idea of the severity of the incident.
Example
The explosion door arrangement (11) for the fired heater is described below in detail after considering an example for the present embodiment in which the selection parameters of the sealing cover (14) are studied.
The type and thickness of the material used to fabricate the sealing cover (14) affects the rupture phenomenon of the sealing cover (14) and therefore is a matter of configuration choice. The preferred material is chosen from the group of Series 300 stainless steel, with types 300, 304 or 316 stainless steel being preferred. The purpose of this example is to determine the typical pressure required to lift the explosion door. In the case of the explosion door that is 646 x 646 mm., an explosion door plate thickness of about 3 mm has been considered in accordance with the preferred embodiment of the invention. The total weight (W) of the explosion door is considered approximately 30 kg. In accordance with a preferred embodiment, a Carbon steel door with 100 mm thick ceramic fiber blanket lining is used and an explosion door angle w.r.t. vertical axis is taken as 11°. Thus, an actual pressure required to open the explosion door for the above example can be calculated as:

Closing torque of the door (T) = W x sin9 x L;
where, L = Centre of gravity of the actual length of the door (~323mm); 9 = Angle of the door with vertical axis;
For the above example,
Torque, T ~ 185 kg-cm
This torque is provided by an internal pressure generated by the fired heater.
P = T / (A x L)
A is the area of the door opening (646mm X 646mm).
For the above example,
P ~ 14 mm WC
Considering friction at the hinge to be 30-40%,
Actual pressure required to open the door for the above example ~ 20 mm WC
(approximate).
Secondly, in the above example the explosion door velocity (V) on explosion can be calculated as:
It is assumed that the door experiences impulse on explosion and the rate of change in momentum is considered with a time of 0.1 seconds. Further, it is also assumed that the door hinge is in ideal condition and no resistance at the hinge is considered.
Explosion pressure considered = 2 PSIG (14000 N/m2);
Force on the door on explosion = P x A = 14000 x 0.646 X 0.646 ~ 5850 N; (1)

Rate of change of momentum = W x delV / (T) = 30 x V / (0.1) = 300V;
(2)
For a hinged door, V = co x r (r= 0.646/2 = 0.343 m) =0.343w;
Comparing equations (1) and (2),
300V = 5850;
i.e. V= 19.5m/s~20m/s;
Angular speed, co = 20 / 0.343 = 58.3 rad /sec. = 58.3 / 6.2832 ~ 9 cycle per second.
Further, actual explosion pressure may be up to 10 PSIG.
Thus, the angular velocity at 10 PSIG, w = 9*10/2 = 45 cycles per second.
For the above example, a Finite element analysis (FEA) has been carried out to estimate the burst pressure of the explosion door. FEA is used to evaluate the static burst pressure of stainless steel (SS) foil of 0.1 mm thick which is used as the sealing cover in accordance with the preferred embodiment of the present disclosure. The failure of the sealing cover is assessed for the following two failure modes. The governing burst pressure will be the least pressure out of the two failure modes which are, (i) Failure Mode A: Bursting of the sealing cover with perfectly bonded edges and (ii) Failure Mode B: Bursting of the sealing cover due to tearing of the foil at the bolt location.
The stainless-steel foil (0.1mm thick) having dimensions of 910 mm x 910 mm is selected as an example in the analysis. For Failure Mode B, it assumed that 10

mm bolts will be used to hold the foil in place and provided at a spacing of 125 mm in both directions. The bolts are modeled as analytical rigid elements. It is assumed that the sealing cover is made of Stainless steel 304 material. The yield stress and ultimate tensile strength of the SS foil at ambient temperature are 177.9 MPa and 496.4 MPa respectively. For the case of Failure Mode-A, it is assumed that the sheet is perfectly bonded at the edges, the edges of the FE Model are fixed in all directions. For the case of Failure Mode-B, the bolts and sealing cover are connected through interaction between them using hard contact in a normal direction and frictionless in a tangential direction. The bolts are fixed in all six degrees of freedom.
For failure mode A, in general, stainless steel metal (SA 304) shows ductile damage, when subjected to extreme loading. To capture such failure, the ductile damage initiation criterion is used to predict the failure of the foil. The failure criterion assumes that the equivalent plastic strain at the onset of damage is a function of stress tri-axiality and strain rate. Fig. 5 shows a damage pattern under uniform pressure of ~ 189 kN/m2. The failure/burst of the sealing cover is expected to occur when the accumulated strain limit damage exceeds the unity. From the analysis, the maximum load-carrying capacity before the burst is estimated at -189 kN/m2 (~ 27.4 PSI).
For failure mode B, the maximum principal stress at damage initiation criteria has been used to predict damage in the vicinity of bolt location. The failure of foil is highly influenced by material properties (such as true stress-strain curve, failure principal stress, and fracture energy). So, the tearing failure of the sealing cover needs to be evaluated for different maximum principal stress of the material. Figs. 6 and 7 show a typical displacement and Von-mises stress profile of the sealing cover made of stainless-steel foil. Further, the stress state of the sealing cover at crack initiation is shown in Fig. 8. From the analysis, the estimated burst pressure ranges between 11-20 kN/m2 (1.59-2.9 PSI).

The burst pressure for the sealing cover made of stainless-steel foil has been estimated for two failure modes. Out of both modes, the lowest failure/burst pressure is obtained when the sealing cover is connected to the door frame using bolts. Thus, it can be considered that the expected burst pressure of the 0.1 mm stainless steel foil (SA304), connected to the door frame using bolts will range from 11 to 20 kN/m2 (1.59-2.9 PSI).
Thus, the proposed explosion door arrangement (11) ensures a leak-tight arrangement that is economical and has a robust construction. It can be retrofitted on all types of new or existing explosion doors, or any large, pressurized vessel where the risk of overpressure needs to be addressed, irrespective of whether they are mechanical or automatic without interfering with their functioning. All explosion doors can be made visibly leak-tight as per the present disclosure by suitable modification of the sealing cover and the sealing cover mounting frame detail. Another advantage is the easy availability of the material, (Even the SS foil is easily available as it is commonly used as a vapor barrier in CF (Ceramic Fiber) lined fired heaters). Another advantage is that the stainless-steel foil, if used, is corrosion resistant and therefore ensures the durability of the leak-proof arrangement. The additional cost involved is also minimal. Another advantage is the sealing cover being easily replaceable due to its bolted configuration. Another advantage is the visibly leak-proof arrangement, as the overpressure in a fired heater can be dangerous and on the basis of the damaged sealing cover indicating the severity of an overpressure incident, the associated risk with the over pressure incident can be identified and based on the degree of severity, the troubleshooting can be carried out.
The disclosure has been described herein, with reference to certain embodiments, in order to enable the reader to practice the disclosure without undue experimentation. However, a person having ordinary skill in the art will readily recognize that many of the components and parameters may be varied or modified to a certain extent or substituted for known equivalents without departing from the

scope of the disclosure. It should be appreciated that such modifications and equivalents are herein incorporated as if individually set forth. In addition, titles, headings, or the like are provided to enhance the reader's comprehension of this document and should not be read as limiting the scope of the present disclosure. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.
Equivalents:
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least

one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general, such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Referral Numerals:

Reference Number Description
Prior art
1 Explosion door
2 Plurality of hinges
3 Fired heater casing
4 Door handle
5 Gasket
6 Door frame
Present Invention
11 Explosion door arrangement
12 Door frame
13 Explosion door
14 Sealing cover
15 Plurality of hinges for explosion door
16 Sealing cover mounting frame
17 Fired heater casing
18 Plurality of bolts
19 Gasket
20 Stiffener plate
21 Plurality of hinges for sealing cover
22 Seating base frame
23 Closing frame

claim:
1. An explosion door arrangement (11) for a fired heater, comprising:
a door frame (12) defining a door opening;
an explosion door (13) configured to cover the door opening;
a sealing cover (14) configured to cover the explosion door (13) and prevent leakage of tramp air into the fired heater;
a sealing cover mounting mechanism configured to mount the sealing cover (14) over the explosion door (13);
wherein the sealing cover (14) is configured to rupture when the pressure in the fired heater increases more than a minimum predetermined threshold value and allows the explosion door (13) to swing open and relieve the pressure inside the fired heater.
2. The explosion door arrangement (11) as claimed in claim 1 comprises a plurality of hinges (15) to pivotally attach the explosion door (11) to the door frame (12).
3. The explosion door arrangement (11) as claimed in claim 1, wherein the sealing cover mounting mechanism comprises a sealing cover mounting frame (16) configured with either the door frame (12) or a fired heater casing (17) around the periphery of the explosion door arrangement (11).
4. The explosion door arrangement (11) as claimed in claim 3, wherein the sealing cover mounting mechanism comprises a plurality of bolts (18) that enter corresponding recesses defined in the sealing cover mounting frame (16).
5. The explosion door arrangement (11) as claimed in claim 3, wherein the sealing cover (14) replacement is facilitated through a plurality of hinges (21) at one edge of the sealing cover mounting frame (16).

6. The explosion door arrangement (11) as claimed in claim 1, wherein the sealing cover (14) is a rectangular metal foil having a thickness in the range of 0.005 - 0.5 mm.
7. The explosion door arrangement (11) as claimed in claim 4 comprising a gasket (19) configured to prevent the leakage of tramp air at bolting locations beneath the sealing cover (14).
8. The explosion door arrangement (11) as claimed in claim 1, wherein an undamaged sealing cover is a visual indicator that the explosion door arrangement (11) is leak-tight.
9. The explosion door arrangement as claimed in claim 1, wherein a degree of damage or rupture of the sealing cover is a visual indicator of a degree of severity of an over pressure incident and is helpful in identification of the associated risks with the over pressure incident.
10. The explosion door arrangement (11) as claimed in claims 1-9 being mounted on a fired heater or any large, pressurized vessel wherein the risk of over pressure needs to be addressed.