Furnaces,
boilers, stoves, vehicles, and lighting all have something in common. They
require high-temperature gaskets for sealing and insulation. Typically, these heat-resistant
gaskets are part of a larger assembly or system. For example, a gas furnace may
contain heat exchangers made of metal plates and high-temperature gaskets. A
variable-speed blower creates a vacuum, induces a draft, and forces hot air
past the primary and secondary heat exchangers, which transfer heat between two
fluids. The heat exchanger gaskets aren't the only components in this complex system,
but they play an important role.
For engineers, choosing the
right materials for heat-resistant gaskets is an essential design
consideration. It's also important to select gasket materials with the right environmental
resistance, but without "over-engineering" the part based on actual service
temperatures. As an experienced gasket fabricator, Elasto Proxy can recommend
the right rubber or non-rubber material for your high-temperature application.
Using water jet cutting, we convert gasket materials cost-effectively without
metal dies or tooling charges. Our skilled production personnel perform gasket
bonding or joining operations with precision.
Material Selection and Heat Exchanger Gaskets
The heat
exchanger gaskets used in gas-fired furnaces illustrate the importance of
material selection. Unlike older heating systems, today's high-efficiency furnaces
burn fuel near the top of the unit. The heated air is drawn downwards and unwanted
byproducts from the combustion process are contained and then vented outside. Carbon
monoxide can be deadly, and odors from combustion are unpleasant. There are
other considerations as well. For gas furnaces with 94% or 96% efficiency,
residual heat is minimal. This means that gaskets used near
vents don't require high-temperature materials.
Near the top of
the furnace, however, temperatures are much hotter. In fact, some combustion
temperatures can reach 850° F. That's much too hot for people's safety or
comfort, so heated air is drawn downward and cooled as it passes through a
series of progressively-narrower metal tubes. This heated air also travels
through a primary heat exchanger near the top of the furnace, and then through a
secondary heat exchanger near the exhaust fan. To support proper heat exchanger
operations, gasket materials that resist specific temperature ranges are
required.
Fiberglass Gaskets vs. Silicone Gaskets
For engineers, understanding
the differences in furnace temperatures can also help contain project costs. As
a rule, gasket materials that withstand higher temperatures are more expensive.
Silicones are synthetic elastomers that resist temperatures as high as 500° F.
Fiberglass is a reinforced plastic that contains woven glass filaments and resists
temperatures as high as 1200° F. This makes fiberglass a good choice for the
gaskets used with primary heat exchangers. Yet fiberglass may not be necessary
for secondary heat exchanger gaskets, where temperatures are significantly
less.
Often, the
gaskets for secondary heat exchangers can use less-expensive silicone instead.
EPDM and NBR rubber may also be appropriate choices, but PVC plastic isn't
because this plastic can emit unpleasant odors when exposed to heat. For
engineers, it's also important to remember that heat exchanger gaskets may need
to be made of materials that meet UL
94 requirements for flame resistance. High-temperature gaskets for other
applications may need to meet other industry guidelines or regulatory requirements.
How Can We Help You?
Do you need
high-temperature gaskets for furnaces, boilers, stoves, vehicles, or lighting?
By working with Elasto Proxy, you can meet all of your application requirements
- including cost-effective custom fabrication. How can we help you? From water
jet cutting to manual secondary operations, we combine state-of-the-art
technology with traditional pride-in-craftsmanship. To learn more, contact
Elasto Proxy.
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