Single mechanical seal
Savino Barbera mechanical seal truly represents a distinguishing feature of our horizontal pumps and includes the following:
- Stationary ring, with gasket, internally mounted in the pump housing.
- Rotating ring fixed by interference on the pump shaft.
- PTFE bellow assuring the correct adherence of the seal faces.
- Plastic-coated corrosion resistant metal spring (PFA).
General technical features
Single mechanical seal for aggressive liquids. Lubricated by the liquid being pumped. Internal, balanced, bellow mounted and equipped with a stainless-steel spring protected by a corrosion resistant plastic coating (PFA):
The assembly inside the pump casing favours the cooling of the sliding elements because the surface in contact with the pumped liquid is greater. This internal mounting also gives more stability to the mechanical seal, especially at the starting-up and stopping of the pump, when the same pressure of the liquid keeps the two seal faces togheter.
The pressure between the seal rings is independent from the pressure of the liquid being pumped and this reduces both frictional wearing and heating development between the sliding parts. This characteristic is fundamental when handling liquids with low boiling point or when service conditions are near vapor pressure, when it is difficult to keep the liquid film between the rings stable.
The flexible bellow design, as rotating ring support, accomplishes several functions: it secures the sealing on the pump shaft and transfers rotation to the dynamic ring, it performs a better distribution of spring loading on faces,
it counterbalances axial/radial motions and misalignment, maintaining the right contact between the sealing faces.
With single spring
The spring, independent from the rotation direction, secures the loading on the seal rings and not the rotation transmission to the dynamic part (which is instead guaranteed by the PTFE bellow). The centrifugal force inside the pump keeps impurities or suspensions away from the sealing device (spring and bellow included) therefore giving self-cleaning features to the seal.
Mechanical seal without setting. Easy-access seal with simple fitting procedure: no particular dimension to take. The seal housing is determined by the inner seat in the pump casing (for the static ring) and by the impeller hub (for dynamic ring mounted on the shaft). So, the assembly and maintenance procedures are very simple.
Corrosion and abrasion resistant material
|Stationary ring||Rotating ring||Gasket||Spring||Bellow|
|EPDM – FPM
Savino Barbera mechanical seal is available in several materials to be in perfect compliance with industrial pumping needs. The seal face pairings are innumerable: they can be selected depending on the operating conditions or the chemical nature of corrosive liquids. Naturally, our experience still remains a useful support for selecting the best configuration for each specific case.
The rings are manufactured with Sintered Ceramic or Silicon Carbide. They are also available in filled PTFE, but only for specific cases.
The mechanical seal bellow is made of PTFE: chemically inert material with great characteristics of self-lubricating and minimum friction coefficient.
The metal spring has a protective coating made of PFA, a chemically inert fluoropolymer, resisting all chemical agents and with low permeability.
Static element gaskets
The static ring gaskets are made of ethylene propylene rubber (EPDM) or fluorinated rubber (FPM). Alternative material for special applications: PTFE.
Mechanical seal for heavy-duty applications
The modular design of the single mechanical seal produced by Savino Barbera makes it suitable for the different
needs of industrial pumping. The possible material pairings are innumerable: mating pairs are selected based on
operating conditions and nature of the corrosive liquids. The chemical resistance is not the only distinguishing
feature of this mechanical seal: in fact, it is absolutely reliable even in other critical situations (solid-laden liquids, thermal expansion, shaft misalignments, wear). The extreme pumping conditions when Savino Barbera seal can be safely used are:
- corrosive and harmful liquids
- liquids with abrasive particles
- liquids with fluctuating temperature
- liquids containing suspensions
- liquids with slurries
|Sintered Ceramic (Al2O3 – 99,5%)||Silicon Carbide (SiC)|
|• elevated hardness and high wear resistance
• perfect resistance to corrosion
• not recommended with hydrofluoric acid
• not recommended with hot caustic solutions
• not recommended in presence of high thermal shocks
|• excellent hardness and wear resistance
• chemically inert
• low friction coefficient
• high resistance to thermal shocks
• high thermal conductivity
|Temperatures allowed||-50°C ÷ +200°C||– 100°C ÷ +250°C|
|Electrical conductivity||non-conductive material||conductive material|
When selecting a mechanical seal, one must never forget to attentively consider some parameters as: reaction and thermal-shock risks, conductivity and thermal dilatation of the wetted parts, friction coefficients and self-lubricating properties of the materials. Our experience is obviously a useful support for selecting the best configuration for each specific case.
Savino Barbera mechanical seal catalogues & manuals
Download here technical sheets for our pumps with mechanical seal:
|Savino Barbera single mechanical seal|
|Savino Barbera double mechanical seal|
Mechanical seal pump or mag-drive pump?
When choosing between mechanical seal pumps and magnetically driven pumps, incorrect installation habits may
be misleading. For example, we are sometimes asked to provide magnetic drive pumps for services not compatible
with hermetically closed pumping: those who prefer magnet assembly can in fact presume that magnet coupling is the safest system compared to mechanical seal. However, while it is true that the mechanical seal is more easily subjected to leakages, on the other hand the supposed leak-proof design of mag-drive pumps can become a problem due to the nature of some liquids. To make an attentive technical choice, we invite you to read this section:
|Mechanical seal design VS sealless magnetic design|
Horizontal mag-drive pump (BM Series).
Horizontal mechanical seal pump (OMA Series).