FORM 25
THE PATENTS ACT, 1970
(Act 39 of 1970)
COMPLETE SPECIFICATION
(See Section 10; Rule 13)
10
Title: “Sliding spacer and its assembly to support the
internal cryogenic process pipe cryoline”
15
Applicants: INOX India Pvt. Ltd.
20
Address: 9th Floor, K P Platina, Race Course, Vadodara -
390007, Gujarat, India.
Nationality: An Indian Company25
30
The following specification describes invention in general manner and
the manner in which it is to be performed:
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straight but it is not stretched tightly and hence do not generate any force5
or stress on the sliding spacer or the wire itself. The wire may be made of
non-corrosive metal or non-metal material, preferably stainless-steel wire is
used for wrapping purpose.
In case of vertically oriented process pipes, the purpose of the wire (105) is10
to keep the sliding spacers (104) in position and not allow the spacers to
slide down. Even for horizontally oriented elements and especially flexible
pipes, this wire (105) does not allow the sliding spacers (104) to slide away
on MLI from its position in case if the element is handled vertically or in any
angle during manufacturing, transportation and installation.15
To be more efficient and to avoid damage of MLI (102) of process pipe, a
radial gap of at least 0.5 mm diameter is maintained between the outer
diameter of MLI (102) and inner diameter of sliding spacer (106), however, if
the line is in horizontal condition these spacers touch the MLI (102) on the20
top side due to gravity. The weight of these spacers is between 40-60 gram
and experimentally it is verified that these hollow barrel shaped sliding
spacers (104) do not damage the MLI (102) outer diameter.
The distance between two sliding spacer (104) is equal or adequate enough25
which is dependent on requirement of its installation, bending of pipe and
the length of process pipe. When these sliding spacers (104) are assembled
in flexible cryoline, the distance between these spacers is fixed to 400mm.
This distance can be reduced however, this will increase the number of
sliding spacers, which will increase the heat load value. Increasing the gap30
might lead to sagging of internal hose and touching the outer hose. Hence,
400mm distance is considered.
In case of rigid cryoline, the location of the spacer (104) is decided as per
diameter & geometry of the rigid process pipe (101). For straight lengths,35
the distance between these spacers is considering the max allowed
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unsupported length allowed for a particular process pipe diameter. For rigid5
lines with bends, based on the flexibility analysis, these spacers are placed
at the bends to control the movement of the process pipe such that the
stress values on the process pipes are within allowable limits.
Sliding spacer (104) thickness affects most on heat load of Cryoline10
performance. As increase in thickness leads to lower performance
thermally. A lower thickness to reduce the thermal load may be
mechanically weak, hence an optimized thickness needs to be decided
which gives lowest thermal loads with maximum capacity to withstand
desired mechanical loads. The thickness of sliding spacer is maintained15
during machining process and good quality control system. These spacers
have a unique hollow barrel shape design and are light weight. They satisfy
the function of a typical internal sliding supports which allows axial
displacement of process pipe with respect to vacuum jacket and restrain the
lateral displacements, however due its hollow barrel shape design, it allows20
lateral displacements of pipe without generating high stresses and forces on
the process pipe and Outer vacuum jacket (OVJ) pipe.
Heat (thermal) load analysis is performed considering sliding spacers are
touching the Outer vacuum jacket (103).25
The said sliding spacers (104) are made in such a way so that its geometry
is optimized to withstand the mechanical loads and have reduced thermal
loads. The way these spacers are held on the insulation does not allow
sliding away of spacers from its position during transportation and material30
handling.
Since, the said sliding spacer assembly can be used for both rigid and
flexible single process cryoline used in any industry and any cryogenic
fluid, hence it has wide application. Due to its hollow barrel type design, it
contributes to less heat load than the conventional designs of sliding35
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I/We claim:5
1. A sliding spacer assembly to support the internal cryogenic process
pipe cryoline (101) to be used at Helium temperature (4K), without 80K
shield, the said sliding spacer assembly comprises:
A hollow barrel shaped sliding spacer (104) comprises an inner portion
(106) and outer portion (107) wherein inner portion (106) of the sliding10
spacer (104) resides on the multilayer insulation (102) on the internal
process pipes while outer portion (107) of sliding spacer resides in
contact inside of the pipe of the outer vacuum jacket (103);
A wire (105) is wrapped on sliding spacers to maintain distance with
each other and to retain position of each sliding spacer on process15
pipe;
Wherein
Radial gap of 0.5 mm is maintained between inner diameter of inner
portion (106) of sliding spacer and outer diameter of MLI insulation
(102) and inner diameter of outer vacuum pipe (103);20
Each sliding spacer (104) is spaced apart from each other on process
pipe cryoline (101).
2. The sliding spacer assembly as claimed in claim-1 wherein sliding
spacer (104) is used for rigid and flexible single pipe cryoline (101).
3. The sliding spacer assembly as claimed in claim-1 wherein sliding25
spacer (104) is made of a low thermal conductivity glass fiber material.