Stenso - Hovedkatalog 2019

2.5.3 Silicone Rubber SIL Also known as MVQ - Outstanding resistance to aromatic and chlorine containing hydrocarbons. - Outstanding resistance to ageing, oxygen and weathering. Limitations: - Restricted low temperature flexibility - Low resistance to polar fluids such as Ketones, Ethers, Esters) Physical data: - Operational temperature : -60 °C up to +220 °C - Tensile strength : to 3-7 MPa - Standard colour : red Advantages: - Retains flexibility continued heatingat low (very low) temperatures - Withstands contiued haeating even at very high temperatures without hardening - Resistant to mineral oils and lubricant greases - Outstanding resistance to ageing, weathering and oxygen - Good alkali resistance Limitations: - Not recommended for use with hydrocarbons such as fuels or paraffins, light petroleum oils and steam pressure above 3,5 bar. - Not resistant to hot water, acids and non mineral truck brake fluids - Low tensile and cracking resistance - Poor resistance to wear and tear 3. Mounting and Operating 3.1. Shaft Shaft surface finish is extremely important for effective sealing and longer service life. Basically, surface hardness of the (running) face must increase with increasing peripheral velocity of shaft. As per DIN 3760 the requisite minimal hardness should be 45 HRC. This hardness should be 55 HRC at 4 m/s and 60 HRC at 10 m/s. Lubrication is also very important. This is discussed further in part 3.3 of this catalogue. As specified by DIN 3760, surface finish must be friction and cause higher temperatures. Errors in workmanship and fabrication, scratches on shaft must be avoided. Even small defects may conrtibute to increase in lubricant film thickness, causing leakage. It is important to avoid parallel chamfering. This can cause pump effect and leakage. . 301 Radial Lip Seal