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1、Parker O-Ring Handbook Catalog ORD 5700A/US Seals ISO 9001 / QS9000 Certified Sections IIntroduction to O-Ring Sealing IIBasic O-Ring Elastomers IIIO-Ring Applications IVStatic O-Ring Sealing VDynamic O-Ring Sealing VIParBak Back-Up Rings VIICompatibility Tables for Gases, Fluids, Solids VIIISpecifi
2、cations IXSizes XAppendix XIIndex Parker Offer of Sale Parker O-Ring Handbook 2001 Edition Copyright 1999, 2001, Parker Hannifin Corporation, Cleveland, OH. All rights reserved. Failure, improper selection or improper use of the products and/or systems described herein or related items can cause dea
3、th, personal injury or property damage. This document and other information from Parker Hannifin Corporation, its subsidiaries and authorized distributors provides product and/or system options for further investigation by users having technical expertise. It is important that you analyze all aspect
4、s of your application and review the information concerning the product or system in the current product catalog. Due to the variety of operating conditions and applications for these products or systems, the user, through his or her own analysis and testing, is solely responsible for making the fin
5、al selection of the products and systems and assuring that all performance, safety and warning requirements of the application are met. The products describes herein, including without limitation, product features, specifications, designs, availability and pricing, are subject to change by Parker Ha
6、nnifin Corporation and its subsidiaries at any time without notice. OFFER OF SALE The items described in this document are hereby offered for sale by Parker Hannifin Corporation, its subsidiaries and its authorized distributors. This offer and its acceptance are governed by the provisions stated on
7、the separate page of this document entitled “Offer of Sale.” WARNING Seals Parker Accessories for O-ring Users Parker O-Ring Handbook 5700 Handbook i Build With The Best! Seals Parker Hannifin Corporation O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 Fax: (859) 335-51
8、28 I. Introduction II. Basic O-Ring Elastomers III. O-Ring Applications IV. Static O-Ring Sealing V. Dynamic O-Ring Sealing VI. Back-Up Rings VII. Compatibility Tables for Gases, Fluids, Solids VIII. Specifications IX. Sizes X. Appendix XI. Index T T T T Table ofable ofable ofable ofable of Content
9、sContentsContentsContentsContents Parker O-Ring Handbook 5700 HandbookIntroduction 1-1 Build With The Best! Seals Parker Hannifin Corporation O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 Fax: (859) 335-5128 Section I Introduction 1.0 How to Use This Handbook1-2 1.1
10、What is an O-ring?1-2 1.2 What is an O-ring Seal?1-2 1.3 Advantages of O-rings1-2 1.4 Operation .1-3 1.5 O-ring Characteristics.1-3 1.6 Limitations of O-ring Use 1-4 1.7 Scope of O-ring Use.1-4 1.7.1 Static Seals1-5 1.7.2 Reciprocating Seals 1-5 1.7.3 Oscillating Seals .1-5 1.7.4 Rotary Seals1-5 1.7
11、.5 Seat Seals1-6 1.7.6 Pneumatic Seals1-6 1.7.7 Vacuum Seals1-6 1.7.8 Cushion Installation1-6 1.7.9 Crush Installation1-6 1.7.10 Rod Wiper Installation1-6 1.8 O-rings as Drive Belts 1-7 1.9 Custom Molded Shapes1-7 1.10 Parker Engineering .1-7 1.11 Comparison of Common Seal Types1-7 1.12 Recommended
12、Design Procedure 1-7 1.12.1 O-Ring Design Procedure Using inPHorm O-Ring Design O-ring and gland constitute the classic O-ring seal assembly. 1.3 Advantages of O-rings They seal over a wide range of pressure, temperature and tolerance. Ease of service, no smearing or retightening. No critical torque
13、 on tightening, therefore unlikely to cause structural damage. O-rings normally require very little room and are light in weight. In many cases an O-ring can be reused, an advantage over non-elastic flat seals and crush-type gaskets. The duration of life in the correct application corre- sponds to t
14、he normal aging period of the O-ring material. O-ring failure is normally gradual and easily identified. Where differing amounts of compression effect the seal function (as with flat gaskets), an O-ring is not effected because metal to metal contact is generally allowed for. They are cost-effective.
15、 Figure 1-1: Basic O-ring Groove Bore Piston Rod Figure 1-2: Basic Gland IntrIntrIntrIntrIntroductionoductionoductionoductionoduction Figure 1-3: Gland and O-ring Seal Parker O-Ring Handbook 5700 HandbookIntroduction 1-3 Build With The Best! Seals Parker Hannifin Corporation O-Ring Division 2360 Pal
16、umbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 Fax: (859) 335-5128 1.4 Operation All robust seals are characterized by the absence of any pathway by which fluid or gas might escape. Detail differ- ences exist in the manner by which zero clearance is obtained welding, brazing, soldering, grou
17、nd fits or lapped finishes or the yielding of a softer material wholly or partially confined between two harder and stiffer members of the assembly. The O-ring seal falls in the latter class. The rubber seal should be considered as essentially an incompressible, viscous fluid having a very high surf
18、ace tension. Whether by mechanical pressure from the sur- rounding structure or by pressure transmitted through hy- draulic fluid, this extremely viscous fluid is forced to flow within the gland to produce “zero clearance” or block to the flow of the less viscous fluid being sealed. The rubber absor
19、bs the stack-up of tolerances of the unit and its internal memory maintains the sealed condition. Figure1-4 illus- trates the O-ring as installed, before the application of pressure. Note that the O-ring is mechanically squeezed out of round between the outer and inner members to close the fluid pas
20、sage. The seal material under mechanical pressure extrudes into the microfine grooves of the gland. Figure 1- 5 illustrates the application of fluid pressure on the O-ring. Note that the O-ring has been forced to flow up to, but not into, the narrow gap between the mating surfaces and in so doing, h
21、as gained greater area and force of sealing contact. Figure 1-6 shows the O-ring and its pressure limit with a small portion of the seal material entering the narrow gap between inner and outer members of the gland. Figure 1-7 illustrates the result of further increasing pressure and the resulting e
22、xtrusion failure. The surface tension of the elastomer is no longer sufficient to resist flow and the material extrudes (flows) into the open passage or clear- ance gap. 1.5 O-ring Characteristics A very early and historically prominent user of O-rings(1) cites a number of characteristics of O-ring
23、seals which are still of interest to seal designers. Extracts of the more general characteristics are listed as follows: Note: While Parker Seal generally agrees with the author on most of his statements, exception will be taken to certain generalizations due to more recent developments in sealing g
24、eometry and improved elas- tomer technology. A. The seals can be made perfectly leak-proof for cases of static pistons and cylinders for fluid pressures up to 5000 psi. (Limit of test pressure). The pressure may be constant or variable. B. The seals can be made to seal satisfactorily between recipro
25、cating pistons and cylinders at any fluid pressure up to 5000 psi. There may be slight running leakage (a few drops per hundred strokes) depending on the film-forming ability of the hydraulic medium. O-rings can be used between rotating members with similar results but in all cases the surface rubbi
26、ng speed must be kept low. C. A single O-ring will seal with pressure applied alternately on one side and then on the other, but in cases of severe loading or usage under necessarily unfavorable conditions, seal life can be extended by designing the mechanism so that each seal is subjected to pressu
27、re in one direction only. Seals may be arranged in series as a safety measure but the first seal exposed to pressure will take the full load. D. O-ring seals must be radially compressed between the bottom of the seal groove and the cylinder wall for proper sealing action. This compression may cause
28、the seal to roll slightly in its groove under certain conditions of piston motion, but the rolling action is not necessary for normal operation of the seals. E. In either static or dynamic O-ring seals under high pressure the primary cause of seal failure is extrusion of the seal material into the p
29、iston-cylinder clearance. The major factors affecting extrusion are fluid pressure, seal hardness and strength, and piston-cylinder clearance. F. Dynamic seals may fail by abrasion against the cylinder or piston walls. Therefore, the contacting surfaces should be polished for long seal life. Moving
30、seals that pass over (1)“O-Ring Seals in the Design of Hydraulic Mechanisms”, a paper presented at the S.A.E. Annual Meeting, January, 1947 by Mr. D. R. Pearl of Hamilton Standard Prop. Div. of United Aircraft Corp. Figure 1-6: O-ring Extruding Figure 1-5: O-ring Under Pressure Figure 1-7: O-ring Fa
31、ilure Figure 1-4: O-ring Installed Parker O-Ring Handbook 5700 HandbookIntroduction 1-4 Build With The Best! Seals Parker Hannifin Corporation O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 Fax: (859) 335-5128 ports or surface irregularities while under hydraulic pres
32、- sure are very quickly cut or worn to failure. G. The shape of the seal groove is unimportant as long as it results in proper compression of the seal between the bottom of the groove and the cylinder wall, and provides room for the compressed material to flow so that the seal is not solidly confine
33、d between metal surfaces. H. The seal may be housed in a groove cut in the cylinder wall instead of on the piston surface without any change in design limitations or seal performance. I. Friction of moving O-ring seals depends primarily on seal compression, fluid pressure, and projected seal area ex
34、posed to pressure. The effects of materials, surfaces, fluids, and speeds of motion are normally of secondary importance, although these variables have not been com- pletely investigated. Friction of O-ring seals under low pressures may exceed the friction of properly designed lip type seals, but at
35、 higher pressures, developed friction compares favorably with, and is often less than, the friction of equivalent lip type seals. J. The effects of temperature changes from +18C to +121C (-65F to +250F) on the performance of O-ring seals depends upon the seal material used. Synthetic rubber can be m
36、ade for continual use at high or low temperatures, or for occasional short exposure to wide variations in temperature. At extremely low temperature the seals may become brittle but will resume their normal flexibility without harm when warmed. Pro- longed exposure to excessive heat causes permanent
37、harden- ing and usually destroys the usefulness of the seal. The coefficient of thermal expansion of synthetic rubber is usually low enough so that temperature changes present no design difficulties. (Note: This may not be true for all elastomer compounds, especially FFKM.) K. Chemical interaction b
38、etween the seal and the hydraulic medium may influence seal life favorably or unfavorably, depending upon the combination of seal material and fluid. Excessive hardening, softening, swelling, and shrinkage must be avoided. L. O-ring seals are extremely dependable because of their simplicity and rugg
39、edness. Static seals will seal at high pressure in spite of slightly irregular sealing surfaces and slight cuts or chips in the seals. Even when broken or worn excessively, seals may offer some measure of flow restric- tion for emergency operation and approaching failure be- comes evident through gr
40、adual leakage. M.The cost of O-ring seals and the machining expense necessary to incorporate them into hydraulic mechanism designs are at least as low as for any other reliable type of seal. O-ring seals may be stretched over large diameters for installation and no special assembly tools are necessa
41、ry. N. Irregular chambers can be sealed, both as fixed or moving-parts installations. Note: See paragraph 1.3 for additional advantages. 1.6 Limitations of O-ring Use Again citing Mr. D. R. Pearls paper (1), limitations of O-ring use are given as: “Although it has been stated that O-rings offer a re
42、a- sonable approach to the ideal hydraulic seal, they should not be considered the immediate solution to all sealing problems. It has been brought out in the forego- ing discussion that there are certain definite limitations on their use, i.e., high temperature, high rubbing speeds, cylinder ports o
43、ver which seals must pass and large shaft clearances. Disregard for these limitations will result in poor seal performance. Piston rings, lip type seals, lapped fits, flat gaskets and pipe fittings all have their special places in hydraulic design, but where the design specifications permit the prop
44、er use of O-ring seals, they will be found to give long and dependable service.” While no claim is made that an O-ring will serve best in all conditions, the O-ring merits consideration for most seal applications except: A. Rotary speeds exceeding 1500 feet per minute contact speed. B. An environmen
45、t completely incompatible with any elas- tomeric material. C. Insufficient structure to support anything but a flat gasket. Note: These points are general statements and there are, of course, numerous exceptions. Details of O-ring seal design in regard to particular situations are discussed in the f
46、ollowing sections: Applications, Elastomers, Fac- tors Applying To all O-Ring Types, Static O-Ring Seals, and Dynamic O-ring Seals, and can be refer- enced as needed. 1.7 Scope of O-ring Use Further discussion in this chapter and in the remainder of this handbook is based on specific types of O-ring
47、 seals and special applications. Definitions of commonly used terms connected with O-ring seals are provided in the glossary contained in the Appendix, Section X. These terms are common to the sealing industry. (1)“O-Ring Seals in the Design of Hydraulic Mechanisms”, a paper presented at the S.A.E.
48、Annual Meeting, January, 1947 by Mr. D. R. Pearl, Hamilton Standard Division of United Aircraft Corp. Parker O-Ring Handbook 5700 HandbookIntroduction 1-5 Build With The Best! Seals Parker Hannifin Corporation O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 Fax: (859) 3
49、35-5128 1.7.1 Static Seals In a truly static seal, the mating gland parts are not subject to relative movement (except for small thermal expansion or separation by fluid pressure), as contrasted from seals in which one of the gland parts has movement relative to the other. Examples of static seals are: a seal under a bolt head or rivet, a seal at a pipe or tubing connection, a seal under a cover plate, plug or similar arrangement or, in