Star-Shaped Sealing Ring

The star-shaped sealing ring is a four-lip seal with an X-like shape, so it is also called an X-ring. It is an improvement and enhancement on the basis of the O-ring. Its cross-sectional dimensions are the same as those of the O-ring of the American AS568A standard, and it can basically replace the use of the O-ring.

Compared with the O-ring, the star-shaped sealing ring forms a lubrication cavity between the sealing lips, which has a smaller friction resistance and a small starting resistance. Because its flash edge is located in the concave part of the cross section, the sealing effect is better. The non-circular cross section effectively avoids the rolling phenomenon during reciprocating motion.

The application range of the star-shaped sealing ring is very wide. Choose the appropriate material according to the temperature, pressure and medium. In order to make the star-shaped sealing ring adapt to the given application, the mutual constraints between all working parameters should be considered. When determining the application range, the peak temperature, continuous working temperature and operating cycle must be considered. In rotating occasions, the temperature rise caused by friction heat must also be considered.

This X-shaped sealing ring is a self-tightening sealing element. The sealing force in the initial state depends on the compression amount and the hardness of the material. As the system pressure increases, the compression deformation of the sealing ring will increase, and the total sealing force will increase, forming a reliable seal.

Product features and applications:

Selection of star-shaped sealing ring

Static sealing or reciprocating linear motion

(1) Hole sealing: The inner diameter of the star-shaped sealing ring should be compatible with the groove, or less than about 2% of the groove bottom diameter. Because the pre-compression force generated by pre-compression can effectively prevent the seal ring from twisting and rolling.

(2) Shaft sealing: The inner diameter of the star-shaped sealing ring should be equal to or slightly larger than the outer diameter of the shaft, which can be controlled within 1%. The seal ring will be easier to install and have a longer service life.

Rotary sealing

The inner diameter of the star-shaped ring is about 2~5% larger than the diameter of the shaft it seals. Because the seal ring will generate friction and heat when it is used in rotation, and the elastomer will shrink after heating (Joule heating effect). In order to ensure lubrication and reliable operation of the seal ring, a star-shaped ring with a larger inner diameter than the shaft diameter must be selected. Generally, a seal ring with a smaller cross-section can meet the needs of static sealing, and conversely, a seal ring with a larger cross-section should be used to meet the requirements of dynamic sealing. In the case of high pressure or large extrusion gap, a rubber material with higher hardness needs to be selected. The best way is to add a PTFE backing ring to prevent damage from high pressure extrusion.

Material

The material is generally Shaw A70 nitrile rubber NBR. Other materials can refer to the materials used for O-rings.

Star Ring Recommended Groove Design

Star-shaped sealing ring-X-RING (American standard AS568A)
Piston rod seal (for shaft)					Piston seal (hole)
Product Model	Specifications and dimensions		Rod seals			Piston seal		Slot width
	Inner diameter dN	Cross-sectional diameter CS	D1	D2		D3	D4	L	W
AS001 AS002 AS003	0.74 1.07 1.42	1.02 1.27 1.52
AS004 AS005 AS006	1.78 2.57 2.9	1.78 1.78 1.78	3	6.1		6	2.9	2	1.55
AS007 AS008 AS009	3.68 4.47 5.28	1.78 1.78 1.78	3.5 4.5 5	6.6 7.6 8.1		7 8 9	3.9 4.9 5.9	2 2 2	1.55 1.55 1.55
AS010 AS011 AS012	6.07 7.65 9.25	1.78 1.78 1.78	6 8 9	9.1 11.1 12.1		10 11 13	6.9 7.9 9.9	2 2 2	1.55 1.55 1.55
AS013 AS014 AS015	10.82 12.42 14	1.78 1.78 1.78	11 13 14	14.1 16.1 17.1		15 17 18	11.9 13.9 14.9	2 2 2	1.55 1.55 1.55
AS016 AS017 AS018	15.6 17.17 18.77	1.78 1.78 1.78	16 17 19	19.1 20.1 22.1		20 21 23	16.9 17.9 19.9	2 2 2	1.55 1.55 1.55
AS019 AS020 AS021	20.35 21.95 23.52	1.78 1.78 1.78	21 22 24	24.1 25.1 27.1		25 26 28	21.9 22.9 24.9	2 2 2	1.55 1.55 1.55
AS022 AS023 AS024	25.12 26.7 28.3	1.78 1.78 1.78	26 27 29	29.1 30.1 32.1		30 31 33	26.9 27.9 29.9	2 2 2	1.55 1.55 1.55