Rotating machine components must be adequately protected so that different lubricants and oils do not leak. It is also necessary to ensure that no pollution penetrates them. Simerings, i.e. radial shaft seals, are responsible for the protection of machinery and equipment in places where rotational motion is transmitted. They may differ in the design, type and material from which they are made, but one thing remains constant – their special, protective function, which allows us to use the machine for a long time.
What are washing machine simerings and shaft seals?
The word simmerring (in Poland it is also written as simmering)comes from the German word Simmer which means ring. This illustrates exactly what it is – a ring for sealing rotating elements working e.g. grease, oil, fuel or water. Very often they can also be found as seals on sliding joints. Simmerings most often operate in pressure conditions up to 0.1 mega Pascal (i.e. 1 atmosphere) and in the temperature range from -30 degrees Celsius, to +110 degrees Celsius (depending on the material from which they are made).
Simering – construction
Although simerings really have a lot of types, they do not fundamentally differ in the basic construction, which consists of four main parts.
- metal stiffening insert (made of unalloyed steel, for example)
- elastic sealing lip(elastomeric outer coat) – can be made of various types of rubber
- pressure spring (non-alloyed spring steel)
- in some simerings you can meet with an additional dust lip
The materials from which simering is made differ in properties, so in order to choose it well, you need to familiarize yourself with the differences, which are mainly possessed by NBR and FPM rubber.
NBR rubber, FPM, or more? Which simering to choose?
The main role of simering is to ensure proper sealing. This is influenced by the temperature at which it will work, the place and the construction. Making a sealing lip from several types of rubber allows you to choose the right one for your device. So what gums can be made from an elastomeric outer jacket?
- NBR rubber – general purpose rubber made of acrylated crystal-butadiene rubber, with increased tolerance to lubricants and oils and fuels, which is especially important for simering, because it is in such an environment that they are used. Since this type of rubber is resistant to the above-mentioned substances, it guarantees tightness of the system, and therefore no leakage of lubricants and oils. Operating temperature from -30 to +100 degrees Celsius.
- FPM rubber – made of fluorine rubber seals allow you to work in a greater temperature range than those made of NBR rubber, namely from -20 to even +200 degrees Celsius. As a rubber of the so-called special purpose, it has a number of properties that provide resistance to many substances. Among other things, these are mineral oils and lubricants, HSC hydraulic fluids, ultraviolet radiation, ozone. In addition, fluoride rubber is characterized by excellent resistance to aging, including thermal.
- silicone – from this type of rubber, simerings are most often chosen, which must work in a very large temperature range, because silicone works without obstacles up to -60 degrees, to +200 (short-term work can run up to +230 degrees). In addition, it is resistant to mineral oils, alcohols, water up to +100 degrees Celsius and lubricants.
- ACM rubber – that is, polyacrylic rubber is resistant to hot petroleum oils, can work in the temperature range from -20 to +150 degrees Celsius and responds well to ozone and other weather influences. However, it is not as flexible as previously mentioned, but it is resistant to swelling
- PTFE – that is, Teflon/Gore-Tex, used in shaft seals instead of spring, because it is characterized by the so-called. plastic memory. This means that materials made of it, when heated, can return to their original shape. Therefore, it performs the spring task, which is responsible for calling the preload.
Simering, in addition to making different types of material, also has different types that correspond to another work.
Here you will find more information on how to order simmering
Simering – what type to choose?
The types of simering you may have include:
- Type A – single-wing with pressure spring.
- Type AO – two-lip, with additional dust lip.
- type AH/AS – pressure simering.
- type B – single-wing simering, in which the outer metal part is not covered with an elastomer.
- type BO – two-lip simering, with an additional dust lip, in which the outer metal part is not covered with an elastomer.
- BABSL – pressure simering with additional dust lip.
- COMBI – the complex shaft seal, which is used in very dusty conditions, consists of simering and an additional polyurethane seal.
- DUO – double simering having two pieces of sealing lip in one outer casing. The most common use of this kind of simering is the separation of different media.
- RWDR-KASETTE – simering with modular design consisting of labyrinth system and proper simering. Cassette simerings are used in special soiling conditions.
- ZBA– single-wing simering without pressure spring.
- ZBL – single-wing simering without pressure spring, in which the outer metal part does not overlap with the elastomer.