I-P
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
I
ID:
Abbreviation for “Inside Diameter”. Used when denoting the inside dimension of a packing set, usually equal to the stem or shaft diameter.
IMPELLER:
The part of a centrifugal pump that, when rotated, will generate pressure and cause flow.
IMPRESSION:
During vulcanization, the design formed in the surface of any rubber article by a method of transfer. See “Fabric Finish.”
INCLUSION:
Foreign matter included in the seal material.
INNER CASE:
A rigid, cup-shaped component of a seal assembly, which is placed inside the outer seal case. It has one or more of the following functions: reinforcing member, shield, spring retainer, lip-clamping device.
INNER PLY:
The inside ply of a multiple-layered joint.
INNER RING:
A solid ring used on the ID of a spiral wound gasket in higher pressure applications. This ring also acts as a compression limiter and provides protection from the media stream.
INPHERNO® GASKETS:
Fire-safe PTFE spiral wound gaskets that successfully passed API 607 fourth edition fire test, providing low stress to seal (torque), high tightness, and PTFE inertness and chemical compatibility. A GORE patented product licensed to VSP Technologies.
INSIDE FACE:
That surface of the inner case which faces, and is usually in contact with, the fluid being sealed.
INSIDE LIP ANGLE:
The angle between the inside lip surface and the axis of the seal case.
INSTALLED FACE-TO-FACE DISTANCE:
The distance between the expansion joint flanges after installation when the system is in the cold (off) position.
INTEGRALLY FLANGED TYPE EXPANSION JOINT:
An expansion joint in which the joint flanges are made of the same material as the body of the joint, as in ÒUÓ type joints.
INTERNAL ARCH CORNER:
An expansion joint corner with the arch formed inwardly that is designed primarily for vacuum service. Generally used in conjunction with a rectangular or square expansion joint.
INTERNAL PRESSURE:
Pressure (Lbs/Sq. Inch) exerted on the ID of a seal.
INTRA-LOCK™:
Unique segmented-gasket technology providing tighter, more mechanically secure fits between gasket segments.
ISO:
Abbreviation for International Standards Organization.
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J
JACKETED GASKET:
Type of gasket with a metallic cover either partially or completely surrounding a filler material to improve temperature, pressure, chemical and crush resistance.
JOINT:
An interstice (crevice) between rigid members of a fluid container.
JUNK RING:
A ring added to the bottom of a packing set as either an anti-extrusion ring or as a bushing. See also “Anti-extrusion Ring”, and “Wiper Ring”.
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L
LANTERN RING:
A ring added to a packing set to assist in the introduction of a flush fluid to the stuffing box. This ring is usually made of plastic or metal.
LATERAL DEFLECTION OR LATERAL MOVEMENT:
The relating displacement of the two ends of the expansion joint perpendicular to its longitudinal axis. Lateral movement is usually caused by the thermal expansion of the ducting system and measured in inches or millimeters.
LATERAL OFFSET:
The offset distance between two adjacent flanges or faces. Can be due to misalignment, equipment settling, or by design to compensate for excessive displacement in the opposite direction during cycle.
LATTICE BRAID®:
A Garlock trade name for a type of braided construction. In this method, the yarn is braided in an interlocking weave, making it very difficult to unravel. This construction yields a dense, tightly woven packing material having a square cross-section. Other packing manufacturers have different names for this braiding method.
LEAKAGE:
An escape of gases or liquids from a piece of equipment.
LEAKAGE RATE:
The quantity of fluid passing through (or around) a seal in a given period of time.
LIP DIAMETER:
The inner diameter of the seal lip, measured with the spring installed.
LIP FORCE:
The radial force exerted by an extension spring and/or lip of a seal on the mating shaft. Lip force is expressed as force per unit of shaft circumference.
LIP HEIGHT:
The axial distance from the outside seal face to the toe face.
LIP ID TO ID ECCENTRICITY:
See: Radial Wall Variance.
LIP INTERFERENCE:
The tendency for a seal’s actual dimension at the lip area to be smaller than the ID or larger than the OD sealing surfaces.
LIP OPENING PRESSURE:
The pressure necessary for flowing air at 10000 cm3/m between the contact surface of a radial lip seal and shaft-size mandrel under the following conditions: the seal case outer diameter clamped to be concentric with the mandrel and the pressurized air applied to the outside lip surface.
LIP SEAL:
Lip seals have a pronounced lip-type design and rely on this lip surface to provide a seal under pressure. Also known as pressure activated.
LIVE LOADING:
The use of Belleville spring washers on packing gland bolts to reduce load loss over time.
LOADLOCK™ GASKETS:
Machined profile gaskets designed and fabricated by VSP Technologies.
LTC & LTC-NR GASKETS:
The lowest stress to seal, 100% PTFE-based gaskets. Designed by VSP Technologies for chemical service on FRP/plastic and thin, flat-face flanges such as API 607 manways.
LUBRICANT STARVATION:
Lack of proper lubrication at the seal interface which may cause premature wear and early failure.
LUBRICATION:
The use of a liquid or fluid to reduce the friction, heat or wear between two surfaces where movement is taking place.
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M
“M” FACTOR:
The factor that provides additional preload capability in the flange fasteners to maintain sealing pressure on a gasket after the internal pressure is applied to the joint. For M+Y Values see “Enginnering Tools” under “Services”
MANUFACTURED FLANGE TO FLANGE DIMENSION:
The manufactured width of the joint measured from the joint flange face to flange face.
MATTE FINISH:
A dull surface, as opposed to a smooth plate finish.
MEDIA:
The fluid which is being sealed.
METAL C-RING:
C-section metal seal with low load characteristics. Plating and coating are added for improved performance.
METAL O-RING:
Hollow tubular seal with circular cross-section. Various shapes and sizes can be fabricated and different plating and coating can be added for better performance.
METAL SEAL:
Seal composed entirely of metal components, which, when compressed between two stationary faces, prevents the passage of a particular media through a specified space or opening.
METHOD 21:
See “EPA Method 21″.
MICRO-VOIDS:
The spaces in a gasket, on a micro level, that allow media permeation.
MIRROR FINISH:
A bright, polished surface.
MISALIGNMENT:
The out-of-line condition that exists between the adjacent face of the equipment/system flanges.
MODULUS:
In the physical testing of rubber, the pressure in pounds per square inch or Newtons per square meter of initial square cross-sectional area necessary to produce a stated percentage of elongation, compression or shear. Directly related to the stiffness of the material.
MOLDED TYPE EXPANSION JOINT:
An expansion joint in which the entire wall of the joint is molded into a ÒUÓ or convoluted configuration. The joint is manufactured by a molding process.
MOV:
Abbreviation for “Motor Operated Valve”, a motor-actuated control valve.
MOVEMENTS:
The dimensional changes which the expansion joint is required to absorb, such as those resulting from thermal expansion or contraction.
MRO:
Abbreviation for “Maintenance and Repair Organization”.
MSS:
Abbreviation for “Manufacturers Standardization Society of the Valves and Fittings Industry”.
MTI:
Abbreviation for Material Technology Institute of the Chemical Process Industry.
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N
NON-METALLIC EXPANSION JOINT:
Expansion joint which utilizes flexible non-metallic material to accommodate joint movements.
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O
O-RING:
An elastomeric seal of homogeneous composition molded in one piece to the configuration of a torus with circular cross section; more simply, a round ring with a round cross section.
OD:
An abbreviation for “Outside Diameter”, used to denote the outside dimension of a packing set (usually equal to the stuffing box bore).
OEM:
Abbreviation for “Original Equipment Manufacturer”.
OFFSET:
The radial distance between the axis of the seal bore and axis of shaft rotation.
OIL SEAL:
A seal designed primarily for the retention of oil.
OIL SWELL:
The change in volume of a gasketing product resulting from contact with oil.
OMNI-DIRECTIONAL STRENGTH:
Strength in all directions.
OPERATING PRESSURE/VACUUM:
The temperature at which the system generally will operate during normal conditions.
OPRA GASKET DESIGNS:
Reduced area gaskets for fragile or low bolt load flanges. VSP Technologies’ patented gasket design creates a modified full-face gasket with minimal gasket contact area to match available flange bolt load.
OUTER CASE:
The outer thin-wall rigid structure of the lip-seal assembly which contains the inner case, the primarily-seal ring, the spring parts, and the secondary seal.
OUTER COVER:
The outside ply of material in a multiplelayer joint.
OUTSIDE LIP ANGLE:
The angle between the outside lip and the axis of the seal case.
OVA:
Abbreviation for “Organic Vapor Analyzer”, a device used to measure the concentration of volatile organic compounds (VOC’s) in the vicinity of a stuffing box, flange, or any seal. An OVA is sometimes referred to as a “sniffer”.
OXIDIZER:
See “Strong Oxidizer”.
OZONE CRACKING:
Surface cracking or cracks caused by exposure to an atmosphere containing ozone.
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P
P X T VALUE:
A numerical value resulting from the multiplication of the internal pressure and the temperature of the fluid involved. In English system, usually psi x °F = PTValue.
PACKING GLAND:
The space into which a compression packing is inserted. Also known as a Stuffing Box.
PACKING GROOVE:
A groove machined into a flange or joint to accommodate a packing ring.
PACKING HOOK:
A tool, similar to a corkscrew, for removing packing from a stuffing box.
PACKING SPACE:
The distance between the shaft or stem surface and the bore of a stuffing box. Packing space (x) can be calculated by the following equation: x = (OD-ID)/2.
PAN-BASED CARBON:
A carbon fiber derived from the carbonization process of a poly acrylonitrile fiber in an inert gas.
PAPER FINISH:
Finish resulting from vulcanizing in contact with paper.
PASSIVE INHIBITOR:
A type of galvanic corrosion inhibitor added to packing which acts as a protective coating to block the transfer of electrons and keep a galvanic reaction from occurring. Graphite foil can be produced with phosphorus added as a passive corrosion inhibitor. See also “Galvanic Corrosion”. Compare with “Active Inhibitor”.
PERMANENT SET:
The degree to which an elastic material fails to return to its initial form after deformation.
PERMEABILITY:
The quality or condition of allowing passage of fluid/gases/air through a material such as rubber.
pH:
The measure of the strength of an acid or base. On the pH scale, a neutral solution (neither acidic or basic) has a pH of 7. Solutions with a pH below 7 are acidic; the smaller the pH value, the more acidic the solution. Solutions with a pH above 7 are basic.
PISTON:
A cylindrically-shaped part which fits within a cylinder and transmits or receives motion by means of a connecting rod (Cylinder Rod).
PITA® GASKET:
100% expanded PTFE gasket with fully encapsulated corrugated, stainless steel insert. VSP Technologies’ patented construction transforms conventional ePTFE into a “spring energized” PTFE gasket that maintains high tightness throughout thermal cycling in all chemical services.
PITCH-BASED CARBON:
A carbon fiber derived from the carbon residue found at the bottom of a cat cracker in a refinery.
PITTING:
Surface cavities that occur on a metal as a result of galvanic corrosion or mechanical erosion.
PLAITED:
Braided.
PLASTICIZER:
A compounding ingredient which can change the hardness, flexibility or plasticity of an elastomer.
PLATE FINISH:
A commercially smooth surface, resulting from vulcanization between press plates (platens).
PLUNGE GROUND:
The surface texture of shaft or wear sleeve produced by presenting the grinding wheel perpendicular to the rotating shaft without axial motion.
PLUNGER:
A cylindrically shaped part that has a uniform diameter and is used to transmit thrust (as in a hydraulic cylinder) or develop pressure and cause flow (as in a reciprocating pump).
PNEUMATIC SEAL:
An extruded or molded elastomeric seal designed to expand and retract to provide a secure, reliable seal that can hold, position, or handle objects in a wide range of applications.
POLYURETHANE:
A synthetic elastomeric material made by chemically reacting a polyol and a diisocyanate in such a manner that a high molecular weight polymer is formed.
PRE-ASSEMBLED JOINT:
The combination of the metal framework and a bellows, factory assembled into a single assembly.
PRE-COMPRESSION:
Compression of the expansion joint during installation (shortening the F/F) so that in the cold position the joint has a given amount of compression in addition to the rated amount of compression. The purpose of pre-compression is to allow for unexpected or additional axial extension.
PRE-SET:
Dimension that joints are deflected to insure that desired movements will take place. See Lateral Offset and Manufactured F/F.
PRESS CURE:
A method of vulcanizing rubber by the use of heated platens, which can be brought together and separated by hydraulic pressure or mechanical action, to cure rubber sheet under pressure.
PRESS LENGTH:
The length of a product that can be vulcanized at one time in a press, limited by the length measurement of the press.
PRESSURE:
Force per unit area, usually expressed in pounds per square inch (PSI) or kilograms per square centimeter.
PRESSURE ABSOLUTE:
The pressure above zero absolute. (i.e the sum of atmospheric and gage pressure)
PRESSURE CYCLING:
The variation of pressure in a system.
PRESSURE, ATMOSPHERIC:
Pressure exerted by the atmosphere at any specific location. Sea level pressure is approximately 14.7 lbs./sq.in. absolute.
PRESSURE, GAUGE (PSIG):
Pressure differential above or below atmospheric pressure, expressed as lbs./sq.in. or psig.
PRIMARY LIP:
The normally flexible elastomeric component of a lip seal assembly, which rides against the rotating surface and affects the seal.
PROTECTIVE COVER:
Outer cover material used to protect boot material during shipment and installation.
psi:
Abbreviation for “Pounds per Square Inch”, a unit of pressure.
PTFE:
Abbreviation for Polytetrafluoroethylene, a polymer having excellent chemical resistance. PTFE dispersion is used as a coating for many styles of packing. Some packing styles are constructed of PTFE fibers. Teflon® is DuPont’s trade name for their PTFE materials.
PULP:
In the papermaking industry, pulp is the primary raw material from which paper is made. It is a cellulose fiber product produced by the mechanical and/or chemical processing of wood.
PUMP SHAFT:
The metal rod connecting the impeller of a pump to the motor.
PURGE FLUID:
A clean liquid (usually water) which is injected through a flush port to flush solid particles from the stuffing box area to minimize abrasive wear.
PURGE PORT:
A hole in the side of a stuffing box through which a flushing fluid is injected.
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