02

O-ring sealing principle!

1) The role of the O-ring is to seal the gap between the sealing surfaces, so that the blocked hydraulic oil can not pass the O-ring. Usually in order to ensure a good sealing effect, o-ring should have a certain amount of pre-compression, the size of the compression has a great impact on the sealing performance, the sealing performance is not good after hours, easy to leak; If the compression stress is too large, the O-ring is easy to distort and shorten its life.

2) Permanent deformation of O-ring

The o-ring has the ability to quickly restore its original shape after the removal of the applied load. However, after long-term use, there is almost always some degree of deformation can not be restored, this phenomenon is called permanent deformation. As a result, the sealing capacity of o-rings decreases. In order to measure the residual elasticity of O-rings, permanent deformation is often used to represent the sealing capacity of O-rings and the ability to restore to the original thickness.

03

What are the international o-ring size standards

1) O-ring standard of American AS 568

AS568O ring size standard is issued by the American Society of Automotive Engineers (S.A.E.), is the world's largest o-ring size standard commonly used by American companies size standard. This diagram specifies inner diameter, cross section, sealing application and tolerance and dimension identification code (dashes) for straight O-ring hub gaskets.

2) O-ring British BS 1806 standard

The BS1806O ring dimensions Guide is published by the British Standards Body and lists all British standard dimensions. The standard includes all five major cross section groups in AS568, and several sizes between the AS568 sizes. BS 1806 has been replaced by BS ISO 3601 because BS 1806 is still widely cited in certain industries/regions of the world and it is still relevant for cross-reference purposes.

3) O-ring international ISO 3601 standard

The ISO3601 standard published by the international organization for standardization contains two groups of circles, class A and class B. Class A meets current specifications of THE American standard AS 568B (900 series nipple O-rings are not included). The ISO 3601-1 dimension code for these O-rings is the same as the AS 568 DASH number. Class B allows the substitution of o-rings in technically acceptable and economical metric sizes, which can then be installed into metric grooves. The first number of the size code indicates the section group (A-E) and the last four numbers indicate the section group number indicates the inner diameter of the O-ring is rounded to one-tenth of A millimeter.

4) O-ring British BS 4518 standard

BS4518 is issued by the British Standards Institute and identifies British standard metric dimensions. Size The code for these O-rings is a four-digit number indicating the ID of the O-rings in 1/10th of a millimeter, followed by the A character and two digits indicating the cross section of the O-rings, also 1/10th of a millimeter.

5) O-ring Swedish SMS1586 standard

SMS1586 refers to the Swedish O-ring mechanical standard. In this standard, O-rings are simply identified by ID and C/S, similar to DIN 3771. In addition, all SMS 1586 O-rings are classified into two groups. The first category, used for dynamic and static installations, is the letter D in our table.

6) O-ring German DIN 3771 standard

The DIN 3771 o-ring standard is published by the German Standards Institute (Deutsches Institut fur Normung). This standard identifies the dimensions of o-rings with ID X C/S and may be followed by a letter indicating the quality level (N -- normal quality; S - Special mass), and codes for rubber polymers and IRHD hardness

7) O-ring French NFT 47-501 standard

NFT 47-501 is published by Franaise de Normalisation(French Institute of Standards). This is very similar to ISO 3601-1 dimensions included and dimensions referenced. The dimensional reference code has been specified with letters for 5 cross section groups (A-E), 4 numbers for ID(rounded to 0.1 mm), a second letter for accuracy level and a third letter for vision (inspection) level. The Precision class is denoted by the letters A(aerospace applications) or G(general purpose applications). The visual classes are N (1.0aQL) and S(. 65 AQL).

O-rings to JIS B 2401

JIS B2401 is the Industrial standard of O-ring size in Japan. This standard, often referred to as the "Japanese standard", is divided into four series according to its application. Each part of the O-ring is ascending numbering code to complete the size reference. P series - Mobile (dynamic)G series - Fixed (static)S series - Special size V series - vacuum flange

9) O-ring metric IS0 6149 standard

ISO 6149 specifies O-rings designed for use in metric pipe joints. This standard includes 13 different sizes and calls metric thread sizes for each o-ring size