oil seals Natural materials used

Metal case
Its function is to offer the shaft seal the necessary rigidity to enable a stable coupling with its relative housing seating. With reference to the elastomer, it may be of an inner (see par. 2.2.1), an outer (see par. 2.2.2) or a part-coated type (see par. 2.2.3). Metal oil seals Material.
2.2.1 – Inner metal case
This solution includes the following advantages:
– It eliminates the risk of corrosion
– It avoids damaging the seating, even if made of a light alloy, thus affording a better opportunity of substitutions without damages.dust seal.
2.2.2 – Outer metal case
This type of case was designed for applications requiring high pulling forces and automated motions based on magnetic systems. In time, it has also been shown that in order to achieve a reliable seal, a ground outer finish and a finely machined seating was needed in addition to the use of sealing materials. Its cost was considerably higher than that of a coated type. It was therefore decided to use it only in combination with high-quality compounds, where most of the cost increase is compensated by the savings in elastomer materials.
At any rate, ROLF solved the problem by producing its seals with their outer surface coated only up to half of its height, as detailed below.
2.2.3 – Part-coated metal case
This solution involves coating the outer case up to about half of its height. This coating is a result of vulcanization and can be plain or corrugated to better fit the assembly forces required by the customers. Metal oil seals Material.
The resulting advantages are:
– excellent locking-in in the housing
– savings of high-quality materials
– ease of assembly
– safety in operation
This type of locking is advisable for projects requiring a particularly challenging application.
2.2.4 – Nature of the materials used for the case
In its standard version the metal case consists of a medium/deep draw steel sheet according to the UNI EN10130 or DIN 1624 standards, of a thickness commensurate with the size of the shaft seal. Where a resistance to corrosive fluids is required, it can be supplied as made from
– Stainless steel, to DIN 17440/tab. 1.54401 or AFNOR Z6 CND 17.11 standards (ex AISI 316)
– Brass, to UNI 4894 standards.
2.3 Spring
The spring has a function that is complementary to the fundamental action provided by the sealing lips. In fact, heat, mechanical deformation and chemical action of the fluids affect the original properties of the rubber. As a result, the original radial force exerted by the sealing element tends to decrease. The function of the spring is to counteract this tendency. The spring is a closely wound helical spring in toric form and possesses a calculated initial pre-loadinging force. This is supplemented by a stabilizing heat treatment performed at a higher temperature than the operating one, which makes it possible to achieve:
– at the design stage: the safety of using the most suitable radial force for the expected application,
– at the operating stage: a guaranteed stability of the radial force itself. The temperature effect actually determines, in the course of time, not merely an alteration of the rubber’s original characteristics, but also a decrease of the mechanical properties of the steel constituting the spring. Metal oil seals Material.
2.3.1 – Nature of the materials constituting the spring
The choice of the materials constituting the spring depends on the type of fluid the Garter spring comes in contact with. In the standard version it consist of a phosphatized, high strength piano wire steel to UNI 3823 or DIN 17223 standards. The standard springs undergo a programmed bedding-in process which allows a precise evaluation of the radial force at the design stage. The use of springs of different material may be considered for particular applications. oil seals Natural materials used.car seal.For instance, in cases requiring a seal against corrosive liquids such as seawater, detergent or acid solutions, bearing seal,a stainless steel spring can be employed, conforming to the following standards:
– DIN 17007 Table 2: 1,4300 or AFNOR Z10 CN 18.09 (ex AISI 302)
– DIN 17007 Table 2: 1,4401 or AFNOR Z6 CND17.11 (ex AISI 316)
– DIN 17007 Table 2: 1,4571 or AFNOR Z8 CNDT 17.12
The use of phosphorous bronze springs, while having the same chemical resistance as stainless steels, is not recommended because of the instability of its dimensional characteristics and the uneven decay of its load capacity.