anyone hate pdf's as much as I do? perverting the soul of the web. In this
case however, it's probably the simplest way to post a 164 page document.
maybe not.
anyway, here is an abstract in case you were wondering whether it was worth
downloading.
SECTION 1.
GENERAL
078-1.1 INTRODUCTION
078-1.1.1 Seals are devices which prevent or control the escape of fluids or
gases and prevent entry of foreign
materials. There are hundreds of sealing devices and it is impossible to
cover each one in this volume. This volume
describes a number of the sealing devices used aboard Navy ships. Emphasis
is placed on devices which are
covered by military specifications or are interchangeable with devices used
in standard configuration glands.
Packings and gaskets are covered in Volume 2.
078-1.2 DEFINITIONS
078-1.2.1 GASKETS, PACKINGS, AND SEALS. In common usage, gaskets, packings,
and seals are terms
which are often used interchangeably. The seals covered in this volume
include those preformed sealing devices
that are manufactured to a specific size for a specific application along
with any associated glands, rings, springs,
and other auxiliary devices. Gaskets and packings, as defined below
(paragraphs 078-1.2.1.1 and 078-1.2.1.2),
are not covered in this volume.
078-1.2.1.1 Gasket. This term is applied to material used to provide a
static seal between two mechanical
joints, in which the sealing material is dependent on mechanical compression
to form the seal. A gasket is often
used to seal mating surfaces without a gland, where low differential
pressure exists across the seal boundary.
Gaskets are usually punched or cut from a sheet of thin, somewhat resilient
material (see Volume 2).
078-1.2.1.2 Packing. This term is applied to material used to provide a seal
in a mechanical coupling where
some form of movement between the surfaces to be sealed is intended or
anticipated. Packing material usually
consists of bulk deformable materials which are shaped by manually adjusted
compression to obtain and maintain
effectiveness (see Volume 2).
078-1.2.1.3 Sealing Device (Seal). A seal is a device which prevents the
escape of a fluid or gas or entry of a
foreign material.
078-1.2.2 GENERAL TERMS. The terms defined in paragraphs 078-1.2.2.1 through
078-1.2.2.4 are frequently
used in describing a sealing device.
078-1.2.2.1 Durometer Hardness. Durometer hardness is an indication of the
hardness of the sealing material
as determined by an indentor (see paragraph 078-2.2.5).
078-1.2.2.2 Squeeze. Squeeze is the amount by which a seal is compressed
(distorted from its molded shape)
when installed in the gland.
78-1
078-1.2.2.3 Dynamic Seal. A dynamic seal is a sealing device used between
parts that have relative motion,
such as piston or shaft seals.
078-1.2.2.4 Static Seal. A static seal is a type of seal where there is no
relative motion between the seal and
any parts in contact with the seal. Limited freedom may be provided to
permit the seal to change its shape within
the gland under pressure.
078-1.2.3 TYPES OF SEALING DEVICES. Sealing devices are often described by
their shape or what they
seal. some of the more commonly used types are listed in paragraphs
078-1.2.3.1 through 078-1.2.3.22.
078-1.2.3.1 O-Ring. An O-ring is a ring (seal) which has a round cross
section.
078-1.2.3.2 Piston Ring. A piston sealing ring is usually one of a series
and is often split to facilitate expansion
or contraction.
078-1.2.3.3 Scraper Ring. A scraper ring is a ring which removes material by
a scraping action.
078-1.2.3.4 T-Ring. A T-ring is a ring which has a T-shaped cross section.
078-1.2.3.5 U-Ring. A U-ring is a ring which has a U-shaped cross section.
078-1.2.3.6 V-Ring. A V-ring is a ring with a V-shaped cross section.
078-1.2.3.7 Wiper Ring. A wiper ring is a ring which removes material by a
wiping action.
078-1.2.3.8 Cup Seal. A cup seal is a sealing device with a radial base
integral with an axial cylindrical projection
at its outer diameter.
078-1.2.3.9 Diaphragm Seal (Flat Diaphragm). A diaphragm seal is a
relatively thin, flat or molded sealing
device fastened and sealed at its periphery with its inner portion free to
move.
078-1.2.3.10 Dished Diaphragm Seal. A dished diaphragm seal is a diaphragm
in which the central area is
depressed in a free state permitting longer travel than a comparable flat
diaphragm.
078-1.2.3.11 Flange (Hat) Seal. A flange (hat) seal is a sealing device with
a radial base integral with an axial
projection at its inner diameter.
078-1.2.3.12 Lip Seal. A lip seal is a sealing device which has a flexible
sealing projection.
078-1.2.3.13 Mechanical Seal. A mechanical seal is a sealing device in which
sealing action is aided by
mechanical force.
078-1.2.3.14 Oil Seal. An oil seal is a sealing device which retains oil.
S9086-CM-STM-010/CH-078V1R2
Steve Spence
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