In the direction perpendicular to a shaft axis.
The ability for a packing material to spread out in the radial direction of a stuffing box when it is compressed.
A type of seal which features a flexible sealing member referred to as a lip. The lip is usually of an elastomeric material. It exerts radial sealing pressure on a mating shaft in order to retain fluids and/or exclude foreign matter.
The total force (load) acting on the seal lip which tends to maintain contact of the lip on the shaft. It is the sum of the forces developed from seal interference and the garter spring.
The difference between the minimum and maximum radial wall dimensions when measured around 360I of the seal lip.
Motion of a shaft back and forth in the direction of its axis.
An oscillating, back and forth motion as it normally pertains to a piston rod or valve stem.
A type of pump that relies on the reciprocating motion of a plunger, or series of plungers, to generate pressure and cause flow.
The degree to which a product returns to its normal dimensions or shape after being distorted.
The increase in thickness of a gasket after a load is removed.
A type of braided construction which yields a soft, flexible packing material having a square cross-section. Also referred to as "Square Braid".
Handling without direct individual contact, usually done with robotic arms.
The ratio of energy given up by the elastomer upon releasing it from a definite deformation to the energy required to produce the deformation. Unless the deforming is momentary, the result obtained will be complicated by the partially plastic nature of the elastomer.
Able to recover rapidly, i.e. elastic.
Segmented metal rings installed directly against the back of the expansion joint flange and bolted through to the metal flange of the pipe.
A long, narrow projection which is normally triangular in cross-section and which is molded into the outside lip surface of a helix seal. It is oriented at an angle to the shaft axis. One end of the rib forms part of the seal-lip contact surface.
A valve in which the movement of the stem is simply reciprocating, with no rotation.
A valve in which the movement of the stem is both reciprocating and rotating at the same time, usually following a helical path.
Abbreviation for the Rubber Manufacturers Association.
Abbreviation for Root Mean Square, used in describing surface finishes of a material. Common units are Micro inches (u inch) or Micrometers (u m).
Root Mean Square, or average deviation from a theoretically perfect surface, is used to define surface finish roughness.
The metal shaft which extends from the piston to outside the cylinder.
Sheet rubber and gasketing material of a uniform width rolled up on itself from which gaskets and other products of various shapes may be cut.
The motion of a body turning on an axis.
A dynamic type of sealing application in which one member remains stationary while the other moves past it in a rotating mode. This type of service generally involves a continuous motion between members and higher surface speeds than those encountered in reciprocating applications. The generally higher degree of frictional heating combined with the fact it is concentrated in one area, sometimes lead to heat-related seal problems.
The warping, bowing or bending of a flange that can occur from too much bolt load.
A trimmed surface with irregularities on the outside and inside lip surfaces in the immediate vicinity of the contact line.
Irregularities in shaft surface texture which result from the production process. (See SAE J448a [June, 1963].)
A braiding method that yields a hollow tube of yarn. See also "Braid Over Braid" and "Braid Over Core".
An abbreviation for "Revolutions Per Minute", a measurement of the rotary speed of a rotating shaft.
A material that is capable of recovering from large deformations quickly and forcibly and can be or already is, modified to a state in which it is essentially insoluble (but can swell) in boiling solvent such as benzene, methyl ethyl keytone, and ethanoltoluene azeotrope.
A measurement of how far a shaft moves in the radial direction.