Domsel Seal BC

Construction and operation of the Domsel BC oil seal

The Domsel BC oil seal belongs to an innovative oil seal type that differs from traditional oil seals. Where conventional seals use a rubber lip with a steel housing and a tension spring, the bc seal uses a so-called diaphragm lip: a short, highly flexible sealing lip that presses against the shaft without a spring. This lip is supported by a metal housing, usually made of steel or stainless steel. Thanks to this design, a gap-free seal is created with very low friction, even at high rotational speeds. In addition, the BC version is specifically configured to block pressure from the outside, making it suitable for applications with external pressure or contamination.

Applications of the BC seal

The Domsel BC oil seal is used in a wide range of sectors, including mechanical engineering, drive technology, pumps, fans, compressors, and industrial installations. It is particularly suitable for situations where the seal must prevent dirt, moisture, air, or other media from entering from the outside. Think of pumps with external fluid pressure, shafts in ventilation systems, or applications where the medium on the outside is under pressure. Due to the low friction resistance and the fact that the sealing lip does not cause grooves in the shaft, the bc seal is also ideal for sensitive or non-hardened shafts.

Materials: what are the options and when do you choose what?

The sealing lip of the Domsel BC oil seal is available in multiple compounds; your choice mainly depends on the medium, temperature, and chemical exposure. NBR is the standard for oil and grease in general industrial conditions (typically -20°C to +100°C). If you need more temperature resistance or chemical resistance, FKM (Viton®) is often the logical upgrade (typically up to around +200°C).
If you want a step up from NBR in terms of mechanical strength, wear resistance, and temperature margin, HNBR is a strong middle-ground option. For water, steam, ozone, and UV, EPDM is suitable (but not for oil/grease). Silicone is mainly chosen for very low temperatures and flexibility, with somewhat lower wear resistance.
For the most demanding chemicals and high temperatures, FFKM is intended: you use it when FKM does not provide sufficient margin. Finally, there is PTFE, with very broad chemical resistance and high temperature resistance; it is also interesting for (partial) dry running, but it does require a neat shaft finish.
In addition to the lip material, you can also match the metal housing to the environment. Steel is the standard choice, while a stainless-steel housing (for example 304 or 316) offers extra assurance in corrosive conditions or when cleanability and hygiene carry more weight, such as in food & pharma.

Material Table

How do you choose the right size and version?

When selecting a suitable oil seal within the Domsel oil seal types, it is important to consider dimensions, material, and application as a whole. You start with the sizing: choose based on the shaft diameter, the bore diameter, and the required installation width, with Domsel generally aligning with common DIN dimensions. Next comes the fit and tolerance aspect: make sure the shaft and the housing bore fall within the specified tolerances so the lip seals stably without excessive interference (unnecessary friction/temperature) and without too little contact (risk of leakage).
Next, you determine the lip material based on the medium, temperature, and pressure. NBR is often sufficient for oil and grease under standard conditions, while FKM or PTFE provides more margin at higher temperatures or chemical exposure. Also consider the installation direction: the Domsel BC is intended for outside sealing (pressure/medium from the outside), while for inside sealing you would more likely choose type A or AB. Finally, it is smart to include any compliance requirements right away, such as FDA compliance, steam resistance, or a stainless-steel housing for corrosive environments and hygienic applications; Domsel has specific versions and compounds for this.

In summary, the Domsel Seal BC is a superior sealing solution specifically designed for rotating machinery in the machine building industry. With its remarkable reduction in frictional moment, excellent pressure and temperature resistance, scratch-free sealing, high chemical resistance, and FDA compliance, the Domsel Seal BC offers reliable and efficient sealing performance. Choose the Domsel Seal BC for your sealing needs and experience the benefits of a top-quality sealing solution in your rotating machinery.

If you want more information, or do you have any question, feel free to contact us!

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