FIELD OF THE INVENTION
[001] The subject matter in general relates to heat treatment after a welding
process. More particularly, but not exclusively, the subject matter relates to relieving stress of a high pressure bypass valve.
BACKGROUND OF THE INVENTION
[002] Background description includes information that may be useful in
understanding the present subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed subject matter, or that any publication specifically or implicitly referenced is prior art.
[003] High pressure safety valves are prepared by welding a valve body to a
seat ring. The welding process commonly used is GTAW welding. Once the welding process is carried out on the valves, there is a need to relieve the residual stresses accumulates during the welding process. Conventionally, induction heating is carried out on the high pressure safety valves to relieve the stress. However, with the existing induction heating technologies, there are difficulties in maintaining the temperature gradient across the cross section, treating nonmagnetic material like nickel alloys to induction fields for creating magnetic fields. Also, more power is utilised for the conventional induction heating methodologies.
OBJECTS OF THE INVENTION
[004] In view of the foregoing limitations inherent in the state of the art, some
of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[005] It is an object of the present disclosure to propose a method of heat
treatment that relives the stress from the high pressure bypass valve before the saturation stage is reached.
[006] It is another object of the present disclosure to propose a method of heat

treatment that reduces the heat loss.
[007] It is yet another object of the present disclosure to propose a method of
heat treatment that maintains the temperature gradient throughout the surface to be heat treated.
[008] These and other objects and advantages of the present invention will be
apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.
SUMMARY OF THE INVENTION
[009] This summary is provided to introduce concepts related to a clamping
device. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0010] The present disclosure relates to a method of heat treatment for
relieving stress from a high pressure bypass valve. The method comprises winding a heating cable around a first member of a high pressure bypass valve to form a single layer of first coil. Coil length of the first coil is kept at five times the cross-sectional thickness of a joint and two successive turns of the first coil are in physical contact with each other. The high pressure bypass valve comprises the first member and a second member and the joint separates the first member from the second member.
[0011] The method further comprises winding the heating cable around the
second member of the high pressure bypass valve to form a single layer of second coil. Coil length of the second coil is kept at five times the cross-sectional thickness of the joint and a distance of the cross-sectional thickness of the joint is maintained between two successive turns of the second coil.

[0012] Other objects, features and advantages of the present disclosure will
become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0013] While the specification concludes with claims particularly pointing out
and distinctly claiming the subject matter that is regarded as forming the present subject matter, it is believed that the present disclosure will be better understood from the following description taken in conjunction with the accompanying drawings, where like reference numerals designate like structural and other elements, in which:
[0014] FIG. 1 is a sectional view of a high pressure bypass valve 100 along
with a heating cable 102 winding; and
[0015] FIG. 2 is a method 200 of heat treatment for relieving stress of the high
pressure bypass valve 100, in accordance with an embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The detailed description of various exemplary embodiments of the
disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein 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.
[0017] It is also to be understood that various arrangements may be devised

that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0018] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, “consisting” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0019] It should also be noted that in some alternative implementations, the
functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0020] Unless otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0021] Referring to FIG. 1, a sectional view of a high pressure bypass valve
100 is shown in accordance with an embodiment. The high pressure bypass valve 100 comprises a first member 104 and a second member 108. The first member 104 is joined to the second member 108 using the welding process. Joint 106 is the

portion where the first member 104 is welded to the second member 108.
[0022] In an embodiment, weld groove depth at the joint 106 may be 38mm
and the cross sectional thickness of the joint 106 may be 80mm.
[0023] In an embodiment, the first member 104 and the second member 108
may be asymmetrical in shape about the joint 106.
[0024] In an embodiment, the second member 108 may be a valve body of the
high pressure bypass valve 100. The valve body may be spherical in shape.
[0025] In an embodiment, a single heating cable 102 may be used to wind the
first member 104 and the second member 108 of the high pressure bypass valve 100. The heating cable 102 may be wound around the first member 104 to form a single layer of first coil 110.
[0026] In an embodiment, the diameter of the heating cable 102 may be 25mm.
[0027] In an embodiment, coil length of the first coil 110 may be five times the
cross-sectional thickness of the joint 106. The first coil 110 may be wound such that its successive turns are in physical contact with each other. That is, there is no gap between the turns of the first coil 110.
[0028] In an embodiment, first turn of the first coil 110 may be wound around
a portion of the first member 104 that may be away from the joint 106 and the last turn of the first coil 110 may be wound around a portion of the second member 108 that may be close to the joint 106. That is, the last turn of the first coil 110 may be wound around the second member 108.
[0029] In an embodiment, the heating cable 102 that was wound around the
first member 104 may be continued to wind the second member 108. The heating cable 102 may be wound around the second member 108 to form a single layer of second coil 112.
[0030] In an embodiment, coil length of the second coil 112 may be five times

the cross-sectional thickness of the joint 106. The second coil 112 may be wound for the said length such that a distance of the cross-sectional thickness of the joint 106 may be maintained between each turn of the second coil 112.
[0031] In an embodiment, the second member 108 with a larger surface area
may act as a heat sink. Therefore, to compensate for the heat dissipation of the second member 108, more power is drawn using the first coil 110 (with no space between each turns) and is distributed to the second coil 112 (with spacing between each turn).
[0032] In an embodiment, the heating cable 102 may be wound around the first
member 104 and the second member 108 such that none of the turns overlap each other.
[0033] In an embodiment, an insulating surface (not shown) may be wound
around the high pressure bypass valve 100 to cover the first member 104 and the second member 108. The thickness of the insulating surface may be uniform throughout the applied surface. The insulating surface may cover all the openings of the high pressure bypass valve 100. The heating cable 102 may be wound over the insulating surface.
[0034] In an embodiment, the thickness of the insulating surface may be
25mm.
[0035] In an embodiment, the insulating surface may be applied to a surface of
the high pressure bypass valve 100 that is 20 times the cross-sectional thickness of the joint 106.
[0036] In an embodiment, ends of the heating cable 102 may be connected to
an induction heating machine (not shown). The high pressure bypass valve 100 may be heated using the induction heating machine for a temperature of 980°C with a gradient of not more than 20°C. The temperature of 980°C with a gradient of 20°C is achieved using the above described setup of coil winding.

[0037] In an embodiment, thermocouples (not shown) may be placed across
outer diameter of a portion of the second member 108 to which pipes are connected. The thermocouples may be used to measure the heating temperature and relay the same to a control device of the induction heating machine.
[0038] In another embodiment, the thermocouples may be placed across inner
diameter of the portion of the second member 108 to which the pipes are connected.
[0039] In an embodiment, the number of thermocouples used may be 3-4 in
numbers.
[0040] FIG. 2 illustrates a method of heat treatment for relieving stress of a
high pressure bypass valve 100. At step 202, the first member 104 and the second member 108 of the high pressure bypass valve 100 may be covered using an insulating surface. The insulating surface may be uniformly spread over the high pressure bypass valve 100 covering all the openings.
[0041] At step 204, the heating cable 102 may be wound around the first
member 104 over the insulating surface to form the single layer of first coil 110.
[0042] At step 206, the coil length of the first coil 110 may be kept at five times
the cross-sectional thickness of the joint 106.
[0043] At step 208, the first coil 110 may be wound such that the successive
turns of the first coil 110 are in physical contact with each other.
[0044] In an embodiment, the last turn of the first coil 110 may be wound
around the second member 108 of the high pressure bypass valve 100.
[0045] At step 210, the heating cable 102 may be wound around the second
member 108 of the high pressure bypass valve 100 over the insulating surface to form the single layer of second coil 112.
[0046] At step 212, the coil length of the second coil 112 may be kept at five
times the cross-sectional thickness of the joint 106.

[0047] At step 214, the second coil 110 may be wound such that a distance of
the cross-sectional thickness of the joint 106 may be maintained between two successive turns of the second coil 110.
[0048] At step 216, the ends of the heating cable 102 may be connected to the
induction heating machine to heat the high pressure bypass valve 100.
TECHNICAL ADVANTAGE
[0049] The present disclosure proposes a method of heat treatment that relives
the stress from the high pressure bypass valve before the saturation is reached.
[0050] The present disclosure proposes a method of heat treatment that reduces
the heat loss.
[0051] The present disclosure proposes a method of heat treatment that
maintains the temperature gradient throughout the surface to be heat treated.
[0052] Furthermore, 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.
[0053] 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 groups used in the appended claims.

[0054] Furthermore, those skilled in the art can appreciate that the terminology
used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0055] The claims, as originally presented and as they may be amended,
encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0056] While the foregoing describes various embodiments of the present
disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. The scope of the present disclosure is determined by the claims that follow. The present disclosure 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.

We claim:
1. A method (200) of heat treatment for relieving stress of a high pressure bypass
valve (100), the method comprising:
winding a heating cable (102) around a first member (104) of a high pressure
bypass valve (100) to form a single layer of first coil (110), wherein coil
length of the first coil (110) is five times the cross-sectional thickness of a
joint (106), wherein:
the joint (106) separates the first member (104) from a second member
(108) of the high pressure bypass valve (100); and
two successive turns of the first coil (110) are in physical contact with
each other; and
winding the heating cable (102) around the second member (108) of the high
pressure bypass valve (100) to form a single layer of second coil (112)
wherein:
coil length of the second coil (112) is five times the cross-sectional
thickness of the joint (106); and
a distance of the cross-sectional thickness of the joint (106) is maintained between each turn of the second coil (112).
2. The method (200) as claimed in claim 1, wherein number of turns in the first
coil (110) are 10.
3. The method (200) as claimed in claim 1, comprising winding at least one of the turns of the first coil (110) around a portion of the second member (108).
4. The method (200) as claimed in claim 1, wherein number of turns in the second coil (112) are 6.
5. The method (200) as claimed in claim 1, comprising covering the first
member (104) and the second member (108) with an insulating surface.
6. The method (200) as claimed in claim 5, comprising winding the heating
cable (102) on top of the insulating surface to form the first coil (110) and the second coil (112).

7. The method (200) as claimed in claim 5, wherein thickness of the insulating
surface is uniform throughout the first member (104) and the second member
(108).
8. The method (200) as claimed in claim 7, wherein the thickness of the
insulating surface is 25mm.
9. The method (200) as claimed in claim 5, comprising closing the openings
defined by the first member (104) and the second member (108) using the
insulating surface.
10. The method (200) as claimed in claim 1, comprising connecting ends of the
heating cable (102) to an induction heating machine.