Q: How do you
compare the APM One-Step Embedded O-ring Self-Sealing Fastener System
to the concept of just adding an O-ring or washer to a standard screw
or bolt? A:
When using just an O-ring or deformable washer (regardless of
material) as a pressure sealer you sacrifice the ability to fully
clamp, plus the degree of thread sealing is not predictable. That's
because the O-ring or washer interferes with achieving 360°
metal-to-metal contact between the underside of the head and mounting
surface.
Q:
How do you compare the use of liquid thread sealants and compounds to
embedded O-ring sealing technology? A:
Both technologies share the goal of high-pressure sealing, but that's
where the similarities end. The APM O-ring washer design provides the
user with a pre-assembled, one-piece fastener, ready to be installed
in one step- eliminating the dependence of the installer to apply the
correct amount of sealant/compound. Its inherent geometric chamber
and nested O-ring creates the perfect solution for maximum sealing
and service reusability which is the result of a unique patented
asymmetrical-shaped chamber. Sealants and compounds do not allow for
easy replacement. They usually require the screw or bolt to be
drilled out for replacement which can be problematic. They are really
intended for one-time use.
Q: How often can APM self-sealing fasteners (screws,
bolts, nuts) be used? A:
The APM design and patent (U.S. patent no. 3,175,454) was conceived
to generate high-pressure fastener sealing to 20,000 psi and maximum
multiple usage. However, this frequently asked question cannot be
answered with a simple number because each application condition is
different in terms of re-installation frequency, in combination with
environmental and operating conditions. Because of the asymmetrical
annular design, minimum O-ring friction occurs producing minimum wear
which results in maximum reusability. Repeat orders from many
customers confirm satisfaction from their field servicing
experiences.
Q:
Besides being pre-assembled is there anything special about these
O-rings and the asymmetrical chamber they reside in? A:
Yes. A special silicone formulation is used that is resistant to salt
water weather, dust, dirt , sunlight, ozone and most acids,
prolonging frequency usage and life of these special self-sealing
fasteners. They have a temperature range of -100°F to +500°F (-73°C
to +260°C). The ring size is also special and are not commercial
standard O-ring sizes. This is important, because they have to be
fabricated to conform to the special (patent no. 3,175,454) curvature
configuration for holding chamber to maintain minimum O-ring surface
friction when torqued. (This is the essence of the patent approval
which contributes to its reusability.) The process requires that only
20% of the O-ring surface be compressed and displaced into a defined
clearance hole which completes the sealing action. By reducing
movement and friction, the integrity of the O-ring surface is
protected from unnecessary wear which would otherwise expose the ring
to degradation from contaminants reducing its future ability to seal
at maximum torque levels.
Q:
Can the APM self-sealing fasteners be supplied with painted heads to
match equipment color? A:
Yes. We have a special bonding process which provides excellent paint
adhesion.
Q:
Can thread locking be added to APM self-sealing fasteners? A:
Yes. For example, you can order an APM SEELSKREW®, SEELBOLT® or SEELNUT® with a fully-adjustable, anti-vibration option. Choice
of resilient engineered embedded polymer pellets, strips (bars), or
standard/high-temperature, surface applied patches can be added to
the threaded area for compression and locking action. Eliminates need
for costly lock washers, cotter pins, or castellated nuts. Impervious
to a wide range of chemicals, water and lubricants. Choice of locking
materials.
Q:
I notice that APM SEELNUT® does not use an
O-ring like your other self-sealing fasteners, and some competitor's
nuts. How does it seal? A:
After patenting the original self-sealing concept that incorporates
an embedded O-ring within a groove of the head of the screw, bolt and
rivet - APM designers soon recognized that an O-ring could not
provide an optimized sealing solution for an effective -self-sealing
nut. A standard nut's geometry combined with an O-ring, could not
work as it does on these other fasteners. Part of the O-ring would be
jutting above the nut and upon compression, would have insufficient
room for expansion. So, APM designed a molded elastomeric insert,
compatible with most gases and liquids (typically silicone), that
could be easily compressed and locked into a contoured channel
located on top of the nut as well as into the mating bolt threads. We
also recognized that an effective self-sealing nut requires the
sealing component to have threads that continue the nut's threads.
This results in additional threaded surface for greater torquing and
sealing capacity. The superior sealing design allows the SEELNUT® to achieve a 6,000 psi rating internal/vacuum - a
feature that could not be accomplished with a pressed O-ring.
UL Recognized APM SEELNUTS® are reusable
and fully adjustable; they resist vibration and provide a 360° metal-to-metal surface contact, and are available in a
wide range of sizes and materials. An optional thread-locking
capability is also offered with the incorporation of a nylon pellet.
Q:
Why is APM's self-sealing washer an ideal solution for NEMA type 4X/6
enclosure sealing? A:
To its advantage, the APM UL Recognized SEELOC® washer looks and performs differently than any other
sealing washer. This compressible stainless steel washer, with a
bonded silicone seal, features two concentric ridges that function as
a barrier-rib - one on the outside edge and the other on the inside
hole surface making sealing contact with the mating screw/bolt shank
creating a perfect high-pressure seal to 100 psi (internal/external).
See all the APM Hexseal Sealing Products at DSEI at the
stand of our premier UK distributor, Air & Marine Products (stand
# N3-460)
DSEI brings together the entire defense and security
industry to source the latest equipment and systems,develop
relationships, and generate new business opportunities.
As the-attend event for 2015 with more exhibitors and
educational content than ever before, DSEI will give you access to:
1,500 international
exhibitors an unrivaled range of suppliers from 121 countries
Specialized Air,
Naval, Land, Security, Medical and Unmanned Zones
6 dedicated seminar
theatres offering free educational sessions and showcases
Over 40 pavilions
including South Korea, Brazil, India, Australia, UK, USA
Expanded live
Waterborne and Unmanned Systems Demonstrations
Static vehicle
displays for land, air and naval sectors - DSEI's biggest
offering yet
International
visiting naval ships available to tour
