Gaskets & Packing Flashcards
Gaskets and packings provide ______ or _____ seals on couplings, glands, and rotating or reciprocating machinery.
static or dynamic
Gaskets depend upon mechanical compression to provide a________ between two stationary joints.
positive seal
Packings generally are used where some form of__________ occurs between members of the joint
relative motion
Packing consists of ________ material which is shaped by adjustable compression to provide a controlled seal.
deformable
Compressibility is usually stated as the percentage difference in _______ between a fully compressed and uncompressed material.
thickness
________ is the relative resistance to indentation of a gasket material. Determined by the use of an indenter with a calibrated force which depresses the material.
Durometer Hardness
______ is a seal provided in a mechanical coupling where movement between the sealed surfaces is intended, such as packing material sealing to a rotating or reciprocating shaft.
Dynamic Seal
______ is the resilient qualities of a gasket material - i.e., the material’s ability to be deformed and to return to its normal state without a permanent change of shape. _______ is lost to compression set and creep.
Elasticity
_______ are material used to create a seal between two stationary faces of a mechanical joint.
Gaskets
________ is 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
______ is a seal in a mechanical joint in which no relative movement of the joint surfaces is intended.
Static Seal
Besides improper installation, ________ are often due to worn or faulty equipment, uneven distribution or excessive bolt torque, nonpar- allel flange faces, aging, and other causes.
gasket failures
During the initial installation of the packing material,_____ are finger-tightened with very little torque, and the packing is permitted to leak freely for the first hour or so of pump operation.
gland nuts
Fluorocarbon fibers such as_____ have an unusually high resistance to chemicals and heat, as well as exceptionally low levels of friction and adhesion.
Teflon
Natural and synthetic rubbers (________) are frequently used in compression packing materials for coatings, impregnations, or as a homogeneous material to enhance sealing.
elastomers
