Authorized Distributor of Parker O-Rings, Parker Seals and Parker Products
Authorized Distributor of Parker O-Rings, Parker Seals and Parker Products
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| N | O | Q | R | S | T | U | V | W | X | Y | Z |
| A | |
| Abrasion | The wearing away of a surface in service by mechanical action such as rubbing,scraping or erosion. |
| Abrasion Resistance |
The ability of a rubber com pound to resist mechanical wear. |
| Absorption: | The physical mechanism by which one sub stance attracts and takes up another substance (liquid, gas, or vapor) into its INTERIOR. |
| Accelerated Life Test |
Any set of test conditions designed to reproduce in a short time the deteriorating effect obtained under normal service conditions. |
| Accelerated Service Test |
A service or bench test in which some service condition, such as speed, or temperature, or continuity of operation, is exaggerated in order to obtain a result in shorter time. |
Accelerator |
A substance which hastens the vulcanization of an elastomer causing it to take place in a shorter time or at a lower temperature. |
| Acid Resistant | Withstands the action of acids. |
| Adhere | To cling or stick together. |
| Adhesion | Tendency of rubber to bond or cling to a con tact surface. |
| Adsorption | The physical mechanism by which one substance attracts another substance (either solid, liquid, gas, or vapor) to its SURFACE and through molecular forces causes the incident substance to adhere thereon. |
| Aging | To undergo changes in physical properties with age or lapse of time. |
| Aging, Oxygen Bomb |
A means of accelerating the change in physical properties of rubber compounds by exposing them to the action of oxygen at an elevated tem perature and pressure. |
| Air Bomb | Similar to an oxygen bomb but used with air. Used for accelerated aging test. |
| Air Checks | Surface markings or depressions due to trap ping air between the material being cured and the mold or press surface. |
| Air Curing | The vulcanization of a rubber product in air as distinguished from vulcanizing in a press or steam vulcanizer. |
| Alpha (α) Particles |
Positively charged particles composed of two protons and neutrons (often referred to simply as helium atom nuclei) and characterized by limited penetration. |
| Ambient Temperature |
The surrounding temperature relative to a given point of application. Note: Ambient temperature is not necessarily the same as atmospheric temperature. |
| Aniline Point | The lowest temperature at which equal volumes of pure, fresh aniline and an oil will completely dissolve in one another |
| Antioxidant | An organic substance which inhibits or retards oxidation. |
| Antiozonant | A substance that retards or prevents the appearance of cracks from the action of ozone when the elastomer is exposed under tension, either statically or dynamically, to air containing ozone. |
| Antirad | A material which inhibits radiation damage. |
| Atmospheric Cracking |
Cracks produced in surface of rubber articles by exposure to atmospheric conditions. |
| B Go to Top | |
| Backrind | Distortion at the parting line usually in the form of a ragged Indentation. |
| Back-Up Ring | (Anti-extrusion device) a ring of relatively hard and tough material placed in the gland between the O-ring and groove side walls, to prevent extrusion of the O-ring. |
| Bake-Out | A process whereby a vacuum system is heated for a given time at some predetermined temperature to degas all the components, i.e. gauges, fittings, valves, seals, etc. |
| Banbury Mixer |
A specific type of internal mixer used to blend fillers and other ingredients with an elastomer. |
| Bench Test | A modified service test in which the service conditions are approximated, but the equipment is conventional laboratory equipment and not necessarily identical with that in which the product will be employed. |
| Beta (β) Particles |
Negatively charged particles or electrons, characterized by limited penetration. |
| Bleeding | Migration to the surface of plasticizers, waxes, or similar materials to form a film or beads. |
| Blemish | A mark, deformity, or injury that impairs the appearance. |
| Blisters | A raised spot in the surface or a separation between layers usually forming a void or air-filled space in the vulcanized article. |
| Bloom | A dusty or milky looking deposit that sometimes appears on the surface of an O-ring after molding and storage, caused by migration of a liquid or solid to the surface. Not to be confused with dust from external sources. |
| Bond | The term commonly used to denote the attachment of a given elastomer to some other member. Bonds may be classified by type as follows: (a) Mechanical Bond — purely physical attachment accomplished by such means as “through” holes interlocking fingers, envelope design, riveting etc. (b) “Cold” Bond — adhesion of previously vulcanized elastomer to another member through use of suitable contact cements. (c) “Vulcanized” Bond — adhesion of an elastomer to a previously primed surface using heat and pressure thus vulcanizing the elastomer at the same time. |
| Break | A separation or discontinuity in any part of an article. |
| Break-Out | Force to initiate sliding. Expressed in same terms as friction. An excessive break-out value is taken as an indication of the development of adhesion. |
| Brittleness | Tendency to crack when deformed. |
| Buna-N | Same as nitrile rubber. |
| Buna-S | A general term for the copolymers of butadiene and styrene. Also known as SBR and GRS. |
| Butt Joint | Joining two ends of a seal whereby the junction is perpendicular to the mold parting line. |
| Butyl | A copolymer of isobutylene with small amounts of isoprene. |
| C Go to Top | |
| Calender | A machine used to form sheets of rubber between steel rollers. |
| Coefficient of Thermal Expansion |
Average expansion per degree over a stated temperature range expressed as a fraction of initial dimension. May be linear or volumetric. |
| Cold Flexibility |
Flexibility following exposure to a predetermined low temperature for a predetermined time. |
| Cold Flow | Continued deformation under stress. |
| Cold Resistant | Able to withstand the effects of cold or low temperatures without loss of serviceability. |
| Commercially Smooth |
Degree of smoothness of the surface of an article that is acceptable for use. |
| Compound | A term applied to a mixture of polymers and other ingredients, to produce a usable rubber material. |
| Compression Modulus |
The ratio of the compressive stress to the resulting compressive strain (the latter expressed as a fraction of the original height or thickness in the direction of the force). Compression modulus may be either static or dynamic. |
| Compression Set |
The amount by which a rubber speci men fails to return to original shape after release of compressive load. |
| Conductive Rubber |
A rubber capable of conducting electricity. Most generally applied to rubber products used to conduct static electricity. |
| Copolymer | A polymer consisting of two different mon omers chemically combined. |
| Corrosion (Packing) |
Corrosion of rigid member (usually metal) where it contacts packing. The actual cor roding agent is fl uid medium trapped in the interface. |
| Corrosive (Packing) |
A property of packing whereby it is assumed often incorrectly, to promote corrosion of the rigid member by the trapped fluid. |
| Cracking | A sharp break or fissure in the surface. Gener ally due to excessive strain. |
| Creep | The progressive relaxation of a given rubber material while it is under stress. This relaxation eventually results in permanent deformation or “set.” |
| Cross-Section | A seal as viewed if cut at right angles to the mold parting line showing internal structure. |
| Cure | See Vulcanization. |
| Cure Date | Date when O-ring was molded; i.e., 2Q94 means second quarter 1994. |
| Curing Temperature |
The temperature at which the rubber product is vulcanized. |
| Cylinder | Chamber in which piston, plunger, ram, rod, or shaft is driven by or against the system fluid. |
| D Go to Top | |
| Degassing | The intentional but controlled OUTGAS of a rubber substance or other material. |
| Diffusion | The mixing of two or more substances (solids,liquids, gases, or combinations thereof) due to the inter mingling motion of their individual molecules. Gases diffuse more readily than liquids; similarly, liquids diffuse more readily than solids. |
| Durometer | (a) An instrument for measuring the hard ness of rubber. Measures the resistance to the penetration of an indentor point into the surface of rubber. (b) Numerical scale of rubber hardness.Dynamic: An application in which the seal is subject to movement, or moving parts contact the seal. |
| Dynamic Packing |
A packing employed in a joint whose members are in relative motion |
Dynamic Seal |
A seal required to prevent leakage past parts which are in relative motion. |
| E Go to Top | |
| Elasticity | The property of an article which tends to re turn it to its original shape after deformation. |
| Elastomer | Any synthetic or natural material with resili ence or memory sufficient to return to its original shape after major or minor distortion. |
| Electron Volt | Unit of energy in atom calculations equal to 1.602 E -12 ergs. |
| Elongation | Generally means “ultimate elongation” or percent increase in original length of a specimen when it breaks. |
| ERG | Unit of energy (C.G.S.) equal to one dyne centimeter or approximately equal to the work done by a force of 1 gram causing a movement of 1 centimeter. |
| Evaporation | The direct conversion from liquid state to vapor state of a given fluid |
| Explosive Decompression |
Rupturing of the substructure caused by the rapid removal of pressure from an elastomer containing dissolved gases. The result is a blistering or swelling of the material. Some elastomeric compounds are quite resistant to explosive decompression. |
| Extrusion | Distortion or flow, under pressure, of portion of seal into clearance between mating metal parts. |
| F Go to Top | |
| Face Seal | A seal between two flat surfaces. |
| Filler | Chemically inert, finely divided material added to the elastomer to aid in processing and improve physical properties, i.e., abrasion resistance and strength — giving it varying degrees of hardness. |
| Flash | Excess rubber left around rubber part after molding due to space between mating mold surfaces; removed by trimming. |
| Flex Cracking | A surface cracking induced by repeated bending or fl exing. |
| Flex Resistance |
The relative ability of a rubber article to withstand dynamic bending stresses. |
| Flock | Fibrous filler sometimes used in rubber com pounding. |
| Flow Cracks | Surface imperfections due to improper flow and failure of stock to knit or blend with itself during the molding operation. |
| Fluid | A liquid or a gas. |
| Friction | Resistance to motion due to the contact of surfaces. |
| Friction (Breakout) |
Friction developed during initial or starting motion. |
| Friction (Running) |
Constant friction developed during operation of a dynamic O-ring. |
| Fuel (Aromatic) |
Fuel which contains benzene or aromatic hydrocarbons. Causes high swell of rubber. |
| Fuel (Nonaromatic) |
Fuel which is composed of straight chain hydrocarbons. Causes little swell of rubber. |
| G Go to Top | |
| Gamma (?) Radiation |
Electromagnetic disturbance (photons) emanating from an atom nucleus. This type of radiation travels in wave form much like X-rays or light, but has a shorter wave length (approx. 1 A° or 10 E -07 mm). It is very penetrating. |
| Gasket | A device used to retain fluids under pressure or seal out foreign matter. Normally refers to a static seal. |
| Gland | Cavity into which O-ring is installed. Includes the groove and mating surface of second part which together confine the O-ring. |
| H Go to Top | |
| Hardness | Resistance to a distorting force. Measured by the relative resistance of the material to an indentor point of any one of a number of standard hardness testing in struments. |
| Hardness Shore A |
The rubber durometer hardness as measured on a Shore “A” gauge. Higher numbers indicate harder material. 35 Shore “A” durometer reading is considered soft. 90 is considered hard. |
| Hermetic Seal | An airtight seal evidencing no detectable leakage. |
| Homogeneous | (a) General - a material of uniform composition throughout. |
| (b) In seals - a rubber seal without fabric or metal reinforcement. | |
| Hypalon | DuPont trade name for chlorosulphonated polyethylene, an elastomer. |
| I Go to Top | |
| Identification | Colored dots or stripes on seals for identification purposes. |
| Immediate Set | The deformation found by measurement immediately after removal of the load causing the deformation. |
| Immersion | Placing an article into a fluid, generally so it is completely covered. |
| Impact | The single, instantaneous stroke or contact of a moving body with another, either moving or at rest, such as a large lump of material dropping on a conveyor belt. |
| L Go to Top | |
| Leakage Rate | The rate at which a fluid (either gas or liquid) passes a barrier. Total Leakage Rate includes the amounts that diffuse or permeate through the material of the barrier as well as the amount that escapes around it. |
| Life Test | A laboratory procedure used to determine the amount and duration of resistance of an article to a specific set of destructive forces or conditions. |
| Linear Expansion: Expansion in any one lineardimen sion or the average of all linear dimensions. |
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| Logy | Sluggish, low snap or recovery of a material. |
| Low Temperature Flexibility |
The ability of a rubber product to be flexed, bent or bowed at low temperatures without cracking. |
| M Go to Top | |
| mm Hg | Millimeters of mercury. In vacuum work, this is a measure of absolute pressure, being the height of a column of mercury that the air or other gas will support. Standard atmospheric pressure will support a mercury column 760 millimeters high (760 mm Hg.) Any value less than this represents some degree of vacuum. |
| Memory | Tendency of a material to return to original shape after deformation |
| Mirror Finish | A bright, polished surface. |
| Mismatch | Unsymmetrical seal caused by dissimilar cavities in mating mold sections. |
| Modulus | Tensile stress at a specified elongation. (Usually 100% elongation for elastomers). |
| Modulus of Elasticity |
One of the several measure ments of stiffness or resistance to deformation, but often incorrectly used to indicate specifically static tension modulus. |
| Mold Cavity | Hollow space or cavity in the mold which is used to impart the desired form to the product being molded. |
| Mold Finish | The uninterrupted surface produced by intimate contact of rubber with the surface of the mold at vulcanization. |
| Mold Lubricant |
A material usually sprayed onto the mold cavity surface prior to the introduction of the un cured rubber, to facilitate the easy removal of the molded rubber parts. |
| Mold Marks | Indentations or ridges embossed into the skin of the molded product by irregularities in the mold cavity surface. |
| Mold Register | Accuracy of alignment or fit of mold sections. |
| Mooney Scorch |
The measurement of the rate at which a rubber compound will cure or set up by means of the Mooney Viscometer test instrument. |
| Mooney Viscosity |
The measurement of the plasticity or viscosity of an uncompounded or compounded, unvulcanized, elastomeric seal material by means of the Mooney Shearing Disk Viscometer. |
| N Go to Top | |
| Nitrile | (Buna-N) The most commonly used elastomer for O-rings because of its resistance to petroleum fluids, good physical properties and useful temperature range. |
| Nominal Dimension |
Nearest fractional equivalent to actual decimal dimension. |
| Non-Blooming | The absence of bloom. |
| O Go to Top | |
| Occlusion | (a) The mechanical process by which vapors, gases,liquids, or solids are entrapped within the folds of a given substance during workin |