How vacuum jacketed pipe
is constructed
 Vacuum jacketed
pipe, also referred to as vacuum insulated
pipe, is constructed of an inner and outer
pipe. The inner pipe, which carries the
cryogenic liquid, is wrapped
with multiple layers of super-insulation
consisting of alternating layers of a
radiant heat barrier material and a
non-conductive spacer material. The air in
the space between the two lines is pumped
out, creating a static vacuum shield. The
vacuum space contains getter materials to
collect out-gassed molecules to further
improve the vacuum.The thermal
barrier between the inner and outer lines is
so effective that even with -452°F liquid
helium flowing through the pipe, the outer
surface remains safe to touch with bare
hands.
Installation is easier;
saves time and money
 Vacuum
jacketed pipe is easier to install than foam
insulated copper pipe because it is
manufactured to meet the specific layout
requirements of your facility.
Pipe sections are joined with vacuum
insulated bayonet connectors that provide
frost-free connections. Bayonet fittings
simplify installation and maintain the
integrity of the insulating system. This
eliminates fabrication work at your
location and shortens the installation
time.
Keep it cold —
minimizing heat transfer
The goal
in transferring cryogenic liquids is to keep the liquid
as cold as possible from the supply tank to
the points of use.
Minimizing
heat transfer (otherwise referred to as heat
leak) is the primary concern in conveying
cryogenic fluids through a pipe system. All
liquids seek equilibrium with surrounding
temperatures. Thus, a cryogen such as liquid
nitrogen at -320°F seeks to reach
equilibrium with the air surrounding the
transfer pipe.
Heat leak drains profits
Reduced process efficiency through:
Loss of cryogen
through evaporation
Diminished
cooling capacity
Inconsistent quality of cryogen delivered
Variation
in cool-down time from one point to another
3 ways heat is
transferred and how VJP reduces it:
Conduction
is reduced
through low conductivity radial
supports to prevent the inner pipe
from touching the outer pipe.
Convection
is prevented
by removing the gas molecules from
the space between the inner and the
outer pipe.
Radiation
is minimized
by wrapping the inner pipe with
multiple layers of reflective
material.
Your old
insulated pipe is costing you MONEY!
For decades, the accepted method of
insulating cryogenic transfer pipe
(typically copper) was to use foam
insulation covered by a protective polyvinyl
chloride layer. This type of insulation is
inexpensive and works well when new,
providing typical heat transfer rates above
20 BTU/hr/ft at LN2
temperatures.
Performance deteriorates rapidly as the
insulation ages. Within about 5 years the
insulation becomes far less effective in
preventing vaporization of the liquid.
Consider
this:
We offer the best vacuum jacketed piping systems in
our nation. Our systems are modular and flexible
and can be rerouted and used anywhere inside or
outside of your plant in a short time. We offer
rigid systems (non flexible) when needed that are
pre-engineered on-site to fit your plant needs and
then custom fabricated and shipped to your location
for assembly. We have the versatility of installing
a temporary VJP system while your current system is
being built. There are situations where lead time
is always a factor to your plants start-ups and need
to get running ASAP. We have a full line of VJP and
equipment in stock and on-site during your
installation in case of curve balls that are
commonly thrown at you during new installations.
Normal installations used to involve pre site survey
and prints are drawn and piping order is submitted
usually taking up to 10-12 weeks for arrival.
That’s something end user’s can not afford. We have
many years of experience in designing and installing
these systems and learned from early age mistakes
that end up very costly on both ends. Learning from
them and implementing a new strategy in a stocking
program makes us a new leader in turnaround and
quality. We are prepared for the challenge of ever
so changing product lines that require short
deadlines. Give us a call were confidant you will
be impressed. We flourish on your repeat business.
It’s a phone call and the job gets done precisely
the first time and you look good for bringing us in.
LN2 or CO2 does not matter with our piping it will
handle both and it’s flexible since freezers today
our going dual usage of cryogen’s. Up to 60 foot
lengths coiled up in a roll makes handling and
shipping a breeze. We stock many length’s and
size’s to fill your plant’s requirements.
VJP SPECS:
The most cost effective way to
transfer cryogenic fluids
Each vacuum jacketed pipe section is
constructed of an inner and outer pipe. The inner
pipe, which carries the cryogenic liquid, is wrapped
with multiple layers of super-insulation. The
insulation consists of alternating layers of radiant
heat barrier material and non-conductive spacer
material. The space between the two lines is
evacuated to the highest industry standards. The
vacuum annulus contains appropriate getter materials
to adsorb out gassed molecules thereby improving
vacuum. The completed pipe section is then cold
tested, inspected checked using a helium mass
spectrometer leak check.
Pipe Joints:
Both rigid and flex systems offer many different
connections JIC, MPT or the best thermal connection
the bayonet joint. (See picture) This joint offers
frost free connections between pipe sections and
makes installation fast no welding in plant or
on-site. This maintains the thermal efficiency of
the piping system.
Bare or raw connections using foam
joints or tape are a major heat loss and cause
saturated liquid to produce vapor surges in your
system thus resulting in poor cryogen use. This
cost’s you money every day the system is in use.
Warranty: Rigid
systems are guaranteed for a period 10 years from
installation date and flex systems carry a 3 year
warranty from installation date.
|
VJP Dimensions |
Heat Leak in BTU/HR |
|
Inner |
Outer |
OD |
Per ft. |
Per
Bayonet |
|
½” |
2” |
2-3/8” |
.32 |
7.0 |
|
¾” |
2” |
2-3/8” |
.42 |
9.1 |
|
1” |
2-1/2” |
2-7/8” |
.47 |
11.7 |
|
1-1/2” |
3” |
3-1/2” |
.57 |
15.2 |
|
2” |
4” |
4-1/2” |
.78 |
17.8 |
|
