In the listing, marking and ordering rotary shaft seals, in other words, ‘when speaking about rotary shaft seals’, three basic sizes are considered: inner diameter (I.D.), outer diameter (O.D.) and height (or width). The order is also written in this order unless otherwise states, and ‘x’ or ‘-’ is used: e.g. 40 x 62 x 10 or 30-52-10.

These three basic sizes indicate that I.D. and O.D. sizes are shaft and bore nominal sizes, and height value is directly the seal’s height value. Actual inner and outer diameter sizes of the seal are different from the shaft and bore sizes. It is designed that the seal inner diameter is smaller than shaft diameter in order to provide sealing, and also it is designed that seal outer diameter is bigger than bore diameter in order to position stable on bore for seal.

In summary, the definition of basic measures is as follows:

d1: Shaft diameter on which seal works

di: Primary sealing lip inner diameter (not shown)

d2: Bore inner diameter

d2’: Seal outside diameter different from housing bore size

b1: Seal height/width to contact bore

b2: The maximum (total) seal height if it has a height longer than b1

Basic format is:

d1 x d2 x b1

In case there is more than one outer diameter or height, separator marks are placed as ‘/’ between the sizes;

ör. 40 x 80 x 10/12 ya da 35-75/65-10/12 gibi.

In outer diameters, firstly bore nominal size is written, and other outer diameters are written after the bore size, whether small or large. diameters are written after the bore size, whether small or large.

In this way, in complex formats, second outer diameter and second height values are written at most. Other forms are not specified in the standard notation. Decimals and percentages are also used for the metric representation of measurements in the inch standard or for the measurement of a limited number of metric products of special design;

ör. 60,33 x 79,40 x 9,52

In cases with multiple outside diameters and/or heights, the expanded format is:

d1 x d2/d2’ x b1/b2