TITLE: MECHANICAL PIPE JOINT
TECHNICAL FIELD
The subject matter described herein, in general, relates to a mechanical
pipe joint and in particular, relates to a mechanical pipe joint for a condenser assembly.
BACKGROUND
In systems involving heat transfer, a condenser is a device or unit used to
condense a substance from its gaseous to its liquid state, by cooling it. In the process,
the latent heat of the substance is transferred to the condenser refrigerant. Condensers
are typically heat exchangers which have various designs and come in many sizes
ranging from rather small (hand-held) to very large industrial-scale units used in
industrial plants. For example, a refrigerator uses a condenser to get rid of heat
extracted from the interior of the unit to the outside air. Condensers are used in air
conditioning, industrial chemical processes such as distillation, steam power plants and
other heat-exchange systems. Use of cooling water or surrounding air as the refrigerant
is common in many condensers.
Since condensers use refrigerant for the purpose of heat transfer, a
refrigerant circuit is required for the flow of refrigerant in the condenser. The
refrigerant circuit uses multiple pipes joined together by pipe joints. Various metal
joining methods such as brazing, welding, soldering and riveting are used for joining
the pipes. Out of the mentioned metal joining methods, brazing is the most widely used
method for pipe joints. While forming a pipe joint by brazing, two or more metal pipes
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are joined together by melting and flowing a filler metal into the joint, wherein the filler
metal has a lower melting point than the adjoining metals.
However, a lot of challenges are associated with forming a pipe joint by
brazing such as blackening effect in case of joining copper pipes. The brazing process is
time consuming and creates critical zones near the joints. Further, the use of eutectic
joint between aluminium and copper is not an economic process during the mass
production. Also, the brazed joint may possess leakage of refrigerant. Furthermore, the
brazed joint is not flexible enough to sustain twisting forces applied on it.
Therefore, a robust, leak proof, cost effective and less time consuming
design is required to meet the challenges faced by existing pipe joints in an effective
way. There is a requirement of improved pipe joint which eradicates the aforementioned
challenges.
SUMMARY
It is an object of the present subject matter to provide a mechanical pipe
joint for condenser refrigerant circuit which is robust.
It is another object of the present subject matter to provide a mechanical
pipe joint which is leak proof joint as the refrigerant passes through it with high
operating pressure.
It is yet another object of the present subject matter to provide a
mechanical pipe joint which is easy to manufacture and includes less time consuming
manufacturing process.
It is yet another object of the present subject matter to provide a
mechanical pipe joint which is free from blackening effect.
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It is yet another object of the present subject matter to provide a process
for forming mechanical pipe joint which is economic.
It is yet another object of the present subject matter to provide a
mechanical pipe joint which is flexible enough to sustain twisting forces applied on it.
It is further object of the present subject matter to provide a mechanical
pipe joint which uses a single pipe for forming the pipe joint.
The present subject matter relates to a mechanical pipe joint for fluidly
connecting a pipe of a refrigerant circuit to a condenser assembly. The mechanical pipe
joint includes a pad assembly configured to retain an inlet portion of the pipe. The pad
assembly comprises a pad member attached to the condenser assembly and a retainer
plate for preventing outward movement of the inlet portion of the pipe. The pad
assembly further comprises a fastening member configured to fixedly hold the pad
member and the retainer plate together.
In one embodiment of the present subject matter, the inlet portion of the
pipe comprises a flange.
In another embodiment of the present subject matter, the pad member
comprises a first hole for housing a HNBR O-ring.
In yet another embodiment of the present subject matter, the pad member
includes a first through hole for enabling passage of a fluid, the first through hole is
concentric to the first hole such that the flange of the inlet portion is disposed at the first
through hole.
In yet another embodiment of the present subject matter, the pad member
comprises a top surface having a second hole.
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In yet another embodiment of the present subject matter, wherein the
retainer plate is disposed over the pad member is configured to guide and hold the metal
pipe.
In yet another embodiment of the present subject matter, wherein the
retainer plate comprises a second through hole and a third through hole such that the
second through hole is concentric to the first hole of the pad member and the third
through hole is concentric to the second hole of the pad member.
In yet another embodiment of the present subject matter, wherein the
fastening member is inserted into the second hole of the pad member and third through
hole of the retainer plate.
In yet another embodiment of the present subject matter, wherein a HNBR
O-ring is disposed in an O-ring groove formed in the first hole of the pad member.
In yet another embodiment of the present subject matter, the pipe and the
pad member are metallic in nature.
In yet another embodiment of the present subject matter, a method for
forming a mechanical pipe joint for a condenser assembly is disclosed. The method
includes forming a first through hole into a metal pad member for passage of a fluid.
Further, the method includes boring a first hole concentric to the first through hole of
the metal pad member. Furthermore, the method includes forming a second hole in the
top surface of the metal pad member. Also, the method includes disposing an inlet
portion of a metal pipe in the first hole and the first through hole with a flange of the
inlet portion housed at the first through hole of the metal pad member, forming a second
through hole and a third through hole in a retainer plate, wherein the second through
hole is concentric to the first through hole of the metal pad member and the third
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through hole is concentric to the second hole of the metal pad member. Subsequently,
disposing the retainer plate over the metal pad member such that the second through
hole surrounds the pipe and the third through hole overlaps with the second hole of the
pad member. Finally, the method includes inserting a fastening member into the second
hole of the pad member and the third through hole of the retainer plate for fixedly
holding the pad member, the retainer plate and the pipe.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The foregoing and further objects, features and advantages of the present
subject matter will become apparent from the following description of exemplary
embodiments with reference to the accompanying drawings, wherein like numerals are
used to represent like elements.
It is to be noted, however, that the appended drawings illustrate only
typical embodiments of the present subject matter, and are therefore, not to be
considered for limiting of its scope, for the subject matter may admit to other equally
effective embodiments.
Figure 1 illustrates a side view of a condenser assembly 100 and a
mechanical pipe joint 102 in accordance with an embodiment of the present subject
matter.
Figure 2 illustrates a perspective view of the condenser assembly 102 the
mechanical pipe joint 108 in accordance with an embodiment of the present subject
matter.
Figure 3 illustrates a sectional view of a mechanical pipe joint 102 in
accordance with an embodiment of the present subject matter.
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Figure 4 illustrates a side view of a mechanical pipe joint 102 in
accordance with an embodiment of the present subject matter.
Figure 5 illustrates a top view of an aluminum pad member 118 in
accordance with an embodiment of the present subject matter.
Figure 6 illustrates a perspective view of the aluminum pad member 118
in accordance with an embodiment of the present subject matter.
Figure 7 illustrates a cross-sectional view of the aluminum pad member
118 in accordance with an embodiment of the present subject matter.
Figure 8 illustrates a side view of a copper pipe 106 in accordance with an
embodiment of the present subject matter.
Figure 9 illustrates a top view of a retainer plate 120 in accordance with
an embodiment of the present subject matter.
Figure 10 illustrates a perspective view of the retainer plate 120 in
accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
The following presents a detailed description of various embodiments of
the present subject matter with reference to the accompanying drawings.
The embodiments of the present subject matter are described in detail with
reference to the accompanying drawings. However, the present subject matter is not
limited to these embodiments which are only provided to explain more clearly the
present subject matter to a person skilled in the art of the present disclosure. In the
accompanying drawings, like reference numerals are used to indicate like components.
The present subject matter provides a robust, easy to manufacture and
assemble mechanical pipe joint for condenser assembly to be used in refrigeration for
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domestic applications. In other words, a mechanical pipe joint is provided that includes
a copper pipe and a metal pad assembly, wherein the metal pipe and the metal pad
assembly are assembled together with a fastening member. Such a mechanical pipe joint
is robust yet flexible enough to sustain twisting forces applied the pipe joint. Further,
the mechanical pipe joint includes a single metal pipe which helps in sustaining leak
proof characteristics at high operating pressure. Furthermore, the mechanical pipe joint
disclosed in the present subject matter is economical for production.
The subject matter described herein relates to a mechanical pipe joint for a
condenser assembly. Figure 1 illustrates a side view of a condenser assembly 100 and a
mechanical pipe joint 102 in accordance with one embodiment of the present subject
matter. For example, and by no way limiting the scope of the subject matter, the
mechanical pipe joint 102 for fluidly connecting a pipe 106 of a refrigerant circuit to a
condenser assembly 100 of the present subject matter is manufactured from a plurality
of components. The components of the mechanical pipe joint 102 include, but are not
limited to, a metal pad assembly 108 and a fastening member 110.
Figure 2 illustrates a perspective view of the condenser assembly 100 and
the mechanical pipe joint 102, showing position of the mechanical pipe joint 102 with
respect to the condenser assembly 100, in accordance with an embodiment of the
present subject matter. Further, the condenser assembly 100 includes a fin array 104 for
heat transfer.
Referring Figure 3, illustrating a sectional view of the mechanical pipe
joint 102 in accordance with an embodiment of the present subject matter. The metal
pipe 106 has an inlet portion 112 and an outlet portion 114 (Figure 8), wherein the inlet
portion 112 includes a flange 116 as shown in Figure 8. The metal pad assembly 108
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comprises an aluminum pad member 118 and a retainer plate 120, wherein the metal
pipe 106 is configured to be securely attached with the aluminum pad member 118 and
the retainer plate 120 to assemble the mechanical pipe joint 102.
In an embodiment, the aluminum pad member 118 includes a first hole
122 for enabling passage of a fluid (refrigerant) and first through hole 124, concentric to
the first hole 122, as shown in Figure 5. Further, the aluminum pad member 118
comprises an O-ring groove 126 for housing a HNBR O-ring 128 (Figure 4) for
prevention of leakage. The flat portions of retainer plate 120 are forced into the O-ring
groove 126 by deforming localized areas to obtain a strained structure of the HNBR Oring
128. The O-ring groove 126 closely surrounds a port in the planar member so that a
relatively thin wall is defined by the O-ring groove 126 and retainer plate 120, the thin
wall may be forced into the O-ring groove 126 to form the acute angle by a chamfer in
the aluminum pad member 118 thereby formation of a trap for the O-ring. Furthermore,
the aluminum pad member 118 has a top surface 130. A second hole 132 is made on the
top surface 130 for housing the fastening member 110. Finally, as shown in Figure 3,
the metal pipe 106 is inserted into the first hole 122 such that the inlet portion 112 rests
in the first hole 122 and the flange 116 of the metal pipe 106 is housed in the first
through hole 124.
As can be seen from Figure 9, the retainer plate 120 includes a second
through hole 134 and a third through hole 136. The second through hole 134 is
concentric to the first hole 122 of the aluminum pad member 118 and the third through
hole 136 is concentric to the second hole 132 of the aluminum pad member 118. The
retainer plate 120 is disposed over the aluminum pad member 118 such that the second
through hole 134 surrounds the metal pipe 106 and the third through hole 136 overlaps
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with the second hole 132 of the aluminum pad member 118. Further, the fastening
member 110 is inserted into the second hole 132 of the aluminum pad member 118 and
the third through hole 136 of the retainer plate 120. The fastening member 110 is
tightened to fixedly hold the aluminum pad member 118, retainer plate 120 and the
metal pipe 106.
In an embodiment of the present subject matter, the aluminum pad
member 118 is extruded from a base material, curved portion and holes of accurate
dimensions are obtained after machining, as shown in Figure 6. The first hole 122 of
diameter 8.6 mm is punched in the aluminum pad member 118 to obtain the passage for
fluid. The first through hole 124 of designed diameter is bored on the surface of pad up
to depth 2.9 mm, wherein the first through hole 124 is concentric to the first hole 122.
Further, an O-ring groove 126 of diameter 13.5mm is made concentric to the above
holes that can contain the HNBR O-ring 128 of 13.4 mm diameter, as shown in Figure
3. Furthermore, a second hole 132 of 3 mm diameter is made at 14 mm centre to centre
distance from the first hole 122. Finally, thread of 3.5 mm is made through the second
hole 132 where the M6 bolt 110 is to be tightened later. The cross-sectional view at AA
(Figure 5) is shown in Figure 7.
In an embodiment of the present subject matter, the metal pipe 106 is
made of copper. The copper pipe 106 (as shown in Figure 8) of designed length is cut
from a standard copper pipe of outer diameter 9.52 mm. After the de-burring operation
one end part is swaged up for inlet portion 112 and similarly other end part is flanged
out for outlet portion. The flange 116 formed on the inlet portion 112 of the copper pipe
106 retains inside first through hole 124 of the aluminum pad member 118.
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In another embodiment, the retainer plate 120 is a mild steel retainer plate.
The mild steel retainer plate 120 is cut out from a base material as per the required
dimension. The mild steel retainer plate 120 is machined and polished to attain the
required dimension. A is made at top to retain the pipe in position. The second through
hole 134 is concentric to the first hole 122 of the aluminum pad member 118. The third
through hole 136 is made at an equal centre to centre distance as of the aluminum pad
member 118. The third through hole 136 is concentric to the second hole 132.
The mechanical pipe joint 102 disclosed in the present subject matter has a
sole purpose to be used in the field of pipe joints specifically and specifically at the
condenser pad and pipe assembly. Though the mechanical pipe joint 102 has application
in domestic condensers, it is not limited the domestic condensers only.
As can be seen from above, the mechanical pipe joint 102 for the
condenser assembly 100 according to the present subject matter addresses the
challenges of faced due to welding in pipe joints. The elimination of welding process
leads to decrease cycle time and cost during the manufacturing. No blackening effect on
copper pipe 106 appears due to the use of thread screw joint. Adequate amount of
torque is to be generated by the fastening member (bolt) 110 to obtain the required
fastening force to keep all elements fixed in position. Low vibrations and flexibility of
using its replaceable parts allow the use of mechanical pipe joint 102 in the field of
domestic air conditioning system. Further, the present subject matter comprises
standard M6 bolt that eliminates brazing process during manufacturing process. Hence,
the blackening effect due to brazing is also eliminated. A single copper pipe is used
instead of a pipe having eutectic joint of copper and aluminium. Also, the present
subject matter discloses nitrile butadiene rubber (NBR) O-ring seal leading to sustain
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pressure more than 115kg/cm2. This pressure is sufficient for application in condensers
of domestic air conditioning system.
The mechanical pipe joint 102 comprises copper pipe 106 which can be
changed as per requirement creating flexibility in its use. The copper pipe 106 can be is
durable. The damaged condenser or other damaged elements can be easily replaced as
the bonding (pipe joint) is done through screw joint. Further, the spare parts of the
mechanical pipe joint 102 are available in standards for easy replacement. The HNBR
O-ring 128 and lubricating oil that keeps the joint leak proof untampered after more
than 20 cycles of twisting. The use of strained structured HNBR O-ring 128 in the Oring
groove 126 of aluminum pad member 118 and flat surface of the retainer plate 120
makes the joint leak proof. The use of HNBR O-ring 128 also affects sustainability to
the twisting force cycles applied on the mechanical pipe joint 102.
The present subject matter comprises a simple bolt tightening process
which leads to increase in mass production rate in comparison to other pipe joint
processes. The screw joining process is a faster process as in comparison to other
joining processes e.g. brazing. Also, the bolt joining process diminishes the cost to a
greater extent. The process eliminates cost of fuel as in the case of brazing and also
reduces work-hours during mass production. The use of single copper pipe also reduces
the cost of eutectic joint (i.e. between copper and aluminium pipes).
The present subject matter provides a smooth passage for the refrigerant
through it. Hence it does not create any critical regions for the flow of fluid and
structure of the mechanical pipe joint 102. The inner surface of the metal pipe 106 and
the aluminum pad member 118 is finished to attain smoothness. The mechanical pipe
joint 102 includes the standard screw joint with appropriate tightening torque which can
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withstand the tensional force of up to 200 N. The mechanical pipe joint 102 remains
leak proof and undamaged below a force of 200 N and the deformation starts beyond
this force.
Although the invention has been described with reference to specific
embodiments, this description is not meant to be construed in a limiting sense. Various
modifications of the disclosed embodiments, as well as alternate embodiments of the
invention, will become apparent to persons skilled in the art upon reference to the
description of the invention. It is therefore, contemplated that such modifications can be
made without departing from the spirit or scope of the present invention as defined.
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WE CLAIM
1. A mechanical pipe joint 102 for fluidly connecting a pipe 106 of a refrigerant
circuit to a condenser assembly 100, the mechanical pipe joint 102 comprising:
a pad assembly 108 configured to retain an inlet portion 112 of the pipe
106, the pad assembly 108 comprising a pad member 118 attached to the
condenser assembly 100 and a retainer plate 120 for preventing outward
movement of the inlet portion 112 of the pipe 106; and
a fastening member 110 configured to fixedly hold the pad member 118
and the retainer plate 120 together.
2. The mechanical pipe joint 102 as claimed in claim 1, wherein the inlet portion
112 of the pipe 106 comprises a flange 116.
3. The mechanical pipe joint 102 as claimed in claim 1, wherein the pad member
118 comprises a first hole 122 for housing a HNBR O-ring.
4. The mechanical pipe joint 102 as claimed in claim 3, wherein the pad member
118 comprises a first through hole 124 for enabling passage of a fluid, the first
through hole 124 is concentric to the first hole 122 such that the flange 116 of the
inlet portion 112 is disposed at the first through hole 124.
5. The mechanical pipe joint 102 as claimed in claim 4, wherein the pad member
118 comprises a top surface 130 having a second hole 132.
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6. The mechanical pipe joint 102 as claimed in claim 1, wherein the retainer plate
120 disposed over the pad member 118 is configured to guide and hold the pipe
106.
7. The mechanical pipe joint 102 as claimed in claim 6, wherein the retainer plate
120 comprises a second through hole 134 and a third through hole 136 such that
the second through hole 134 is concentric to the first hole 122 of the pad member
118 and the third through hole 136 is concentric to the second hole 132 of the pad
member 118.
8. The mechanical pipe joint 102 as claimed in claim 1, wherein the fastening
member 110 is inserted into the second hole 132 of the pad member 118 and third
through hole 136 of the retainer plate 120.
9. The mechanical pipe joint 102 as claimed in claim 1, wherein a HNBR O-ring
128 is disposed in an O-ring groove formed in the first hole 122 of the pad
member 118.
10. The mechanical pipe joint 102 as claimed in claim 1, wherein material of the pipe
106 is copper and material of the pad member 118 is aluminium.
11. A method for forming a mechanical pipe joint 102 for a condenser assembly 100
comprising:
forming a first hole 122 into a pad member 118 for housing an O-ring;
boring a first through hole 124, concentric to the first hole 122 in a top
surface 130 of the pad member 118;
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forming a second hole 132 in the top surface 130 of the pad member 118;
disposing an inlet portion 112 of a pipe 106 in the first hole 122 and the
first through hole 124 such that a flange 116 of the inlet portion 112 is
housed in the first through hole 124;
forming a second through hole 134 and a third through hole 136 in a
retainer plate 120, wherein the second through hole 134 is concentric to
the first through hole 124 and the third through hole 136 is concentric to
the second hole 132;
disposing the retainer plate 120 over the pad member 118 such that the
second through hole 134 surrounds the pipe 106 and the third through hole
136 overlaps with the second hole 132 of the pad member 118; and
inserting a fastening member 110 into the second hole 132 of the pad
member 118 and the third through hole 136 of the retainer plate 120 for
fixedly holding the pad member 118, the retainer plate 120 and the pipe
106.