O-Ring Guide
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O-RING GUIDE // ZATKOFF.COM Failure, improper selection or improper use of products or systems, the user, through his or her the products and/or systems described herein or own analysis and testing, is solely responsible related items may cause death, personal injury or for making the final selection of the products and property damage. systems and assuring that all performance, safety and warning requirements of the application are met. This document and other information from Zatkoff Seals & Packings provides product and/or system The products described herein, including without options for further investigation by users having limitation, product features, specifications, designs, technical expertise. It is important that you analyze availability and pricing, are subject to change by all aspects of your application and review the Zatkoff Seals & Packings at any time. information concerning the product or system in the current product catalog. Due to the variety of operating conditions and applications for these OFFER OF SALE The items described in this document are hereby Copyright © 2019, Zatkoff Seals & Packings, offered for sale by Zatkoff Seals & Packings. This Farmington Hills, MI. All rights reserved. offer and its acceptance are governed exclusively by the provisions contained in Zatkoff Seals & Packings’ “Offer of Sale” located at www.zatkoff.com/terms. WARNING: These products can expose you to chemicals including carbon black (airborne and extracts), antimony trioxide, titanium dioxide, silica (crystalline), di(2-ethylhexyl)phthalate, ethylene thiourea, acrylonitrile, 1,3-butadiene, epichlorohydrin, toluenediisocyanate, tetra uoroethylene, ethylbenzene, formaldehyde, furfuryl alcohol, glass fibers, methyl isobutyl ketone, nickel (metallic and compounds), lead and lead compounds which are known to the State of California to cause cancer; and 1,3-butadiene, epichlorohydrin, di(2-ethylhexyl)phthalate, di-isodecyl phthalate, ethylene thiourea, methyl isobutyl ketone, methanol, toluene, lead and lead compounds which are known to the State of Califormia to cause birth defects and other reproductive harm. For more information go to www.P65Warnings.ca.gov. 2 O-RING GUIDE O-RING GUIDE // ZATKOFF.COM Table of Contents // ZATKOFF.COM Material Offering 4 Engineering Tools 27 Gland Designs 36 Sizing Charts 46 Metric O-Rings 64 O-Ring Kits 128 3 Material Offering Elastomers The basic core polymer of an elastomeric compound is called a rubber, produced either as natural gum rubber in the wild, on commercial rubber plantations or manufactured synthetically by the chemical industry. Today, more than 32 synthetic rubbers are known, the most important ones are listed on page 5. Modern elastomeric sealing compounds generally contain 50 to 60% base polymer and are often described simply as “rubber.” The balance of an elastomer compound consists of various fi llers, vulcanizing agents, accelerators, aging retardants and other chemical additives which modify and improve the basic physical properties of the base polymer to meet the particular requirements of a specifi c application. Elastomers used in producing seals, and particularly those used in O-rings, will usually provide reliable, leak-free function if fundamental design requirements are observed. “Cross-linking” between the polymer chains is formed during the vulcanization process, see “Schematic Representation of Polymer Chains Before and After Vulcanization.” Cross-linking of the molecules changes the rubber from a plastic-like material to an elastic material. After vulcanization, including any required “post-cure,” an elastomer compound attains the physical properties required for a good sealing material. As with all chemical reactions, temperature is responsible for the speed of reaction. Only when the ideal process temperature is constant during the entire vulcanization time, will the optimum degree of curing be reached. For this reason, the conditions of vulcanization are closely controlled and recorded as part of the Parker quality assurance process. Introduction to Elastomers Before reviewing the available elastomers and their general properties, it is necessary to fully understand the terms “polymer,” “rubber,” “elastomer” and “compound” as they are used in this handbook. Schematic Representation of Polymer Chains Before and After Vulcanization Polymer A polymer is the “result of a chemical linking of molecules into a long chain-like structure.” Both plastics and elastomers are classifi ed as polymers. In this handbook, polymer generally refers to a basic class of elastomer, members of which have similar chemical and physical properties. O-rings are made from many polymers, but a few polymers account for the majority of O-rings produced, namely Nitrile, EPDM and Neoprene. 4 MATERIAL OFFERING MATERIAL OFFERING 5 Rubber Rubber-like materials fi rst produced from sources other than rubber trees were referred to as “synthetic rubber.” This distinguished them from natural gum rubber. Since then, usage in the industry has broadened the meaning of the term “rubber” to include both natural as well as synthetic materials having rubber-like qualities. This handbook uses the broader meaning of the word “rubber.” Elastomer Though “elastomer” is synonymous with “rubber,” it is formally defi ned as a “high molecular weight polymer that can be, or has been modifi ed, to a state exhibiting little plastic fl ow and rapid, nearly complete recovery from an extending or compressing force.” In most instances we call such material before modifi cation “uncured” or “unprocessed” rubber or polymer. When the basic high molecular weight polymer, without the addition of plasticizers or other dilutents, is converted by appropriate means to an essentially non-plastic state and tested at room temperature, it usually meets the following requirements in order to be called an elastomer: A. It must not break when stretched approximately 100%. B. After being held for fi ve minutes at 100% stretch, it must retract to within 10% of its original length within fi ve minutes of release. Note: Extremely high hardness/modulus materials generally do not exhibit these properties even though they are still considered elastomers. The American Society for Testing and Materials (ASTM) uses these criteria to defi ne the term “elastomer.” Compound A compound is a mixture of base polymer and other chemicals that form a fi nished rubber material. More precisely, a compound refers to a specifi c blend of chemical ingredients tailored for particular required characteristics to optimize performance in some specifi c service. The basis of compound development is the selection of the polymer type. There may be a dozen or more different ones to choose from. The rubber compounder may then add various reinforcing agents such as carbon black, curing or vulcanizing agents (such as sulfur or peroxide, activators, plasticizers, accelerators, antioxidants, or antiozonants) to the elastomer mixture to tailor it into a seal compound with its own distinct physical properties. Since compounders have thousands of compounding ingredients at their disposal, it seems reasonable to visualize two, three, or even one hundred-plus compounds having the same base elastomer, yet exhibiting marked performance differences in the O-ring seal. The terms “compound” and “elastomer” are often used interchangeably in a Infl uence of the Acrylonitrile Content more general sense. This usage usually Swelling in IRM 903 oil Cold Flexibility references a particular type or class of materials such as “nitrile compounds” or “butyl elastomers.” Please remember that when one specifi c compound is under discussion in this handbook, it is a blend of various compounding ingredients (including one or more base elastomers) with its own 20 30 40 50 individual characteristics and identifi cation Acrylonitrile Content in % in the form of a unique compound number, For example, N0674-70 or V1164-75. 6 MATERIAL OFFERING Compound Selection and Numbering Systems The base elastomer and the hardness of the finished product are the main factors which enable a given compound to resist heat, chemical and other physical influences. The Parker compound code contains all the essential information needed to identify the polymer family as well as the special property description and hardness. Polymer Codes: A = Polyacrylate B = Butyl C = Chloroprene (Neoprene ®) E = Ethylene-propylene F = ULTRA™FFKM H = Hifluor™ I = HNBR J = Fluorosilicone N = Nitrile (Buna N) and HNBR O = Polyurethane P = Silicone Q = Fluorocarbon, AFLAS®, Ultra™ and Hifluor™ R = Epichlorohydrin S = Exotic Polymers Special Property Descriptions: In the Type II numbering system, the special property description is identified by a second letter A = General Purpose B = Low Compression Set E = Ethylene Acrylate or (vamac®) F = Fuel Resistant or Fully Fluorinated G = High Fluorine Content J = NSF/FDA/WRAS Approvals K = Internally Lubed L = MIL/AMS Specifications P = Low Temperature Flexible or (AFLAS) Q = Non-Black Compound R = Carboxylated The shore hardness range of a compound is indicated by the suffix numbers, e.g. “70” means that the material’s hardness is 70±5 Shore A. The individual sequential compound number is shown between the suffix and the prefix. Note: There are two types of nomenclature used to reference Parker O-Ring Products. See Tables below for description of these types. Type I: N = Polymer Code (Single Letter) 0674 = Sequence Number (Four Digits) -70 = Durometer Indicator (Two Digits) Type II: A =