Stable operation with Fristam-compatible mechanical seals

In modern process plants, where liquids are pumped under pressure and at varying temperatures, a well-functioning mechanical seal is essential for operational reliability, product safety and hygiene. A mechanical seal forms the barrier between the rotating shaft and the pump house and prevents contamination and media loss during operation. This also applies to Fristam pumps, which are used in demanding production environments in the food and pharmaceutical industries. Our Fristam-compatible mechanical seals are designed for precisely these conditions, and we supply them in several configurations to suit the pump's design and operation. 

If you need a more detailed explanation of how a mechanical seal works and its application, watch this video, which thoroughly explains the advantages of mechanical seals.

A mechanical seal consists of a stationary sealing surface and a rotating mating surface, which together form a controlled, dynamic sealing point around the shaft. This helps to prevent the product from escaping along the shaft during operation. 

In many hygienic pump solutions, including Fristam variants, an open pressure spring is used in combination with O-rings as secondary seals between adjacent components. 

This construction provides an effective and easy-to-clean solution that remains stable even with frequent CIP cleaning and prolonged operation, provided that the materials are adapted to the process medium. 

For Fristam pumps with shaft diameters of 22 mm, 30 mm and 35 mm, we offer three variants that cover the requirements for both seat type and direction of rotation. 

We supply Fristam mechanical seals with a high seat and right rotation, designed as an open type with a visible pressure spring and o-ring as a secondary seal. The solution is optimised for pumps with clockwise rotation and is available with a carbon slide ring and a stationary part in stainless steel or silicon carbide. You can choose gaskets in EPDM, NBR or viton – depending on the chemistry of the medium and the operating temperature.  

If you have limited space around the pump, we recommend the variant with a low seat and right rotation. Here, you mount the gasket with the o-ring directly around the shaft, and the construction is the same: open, simple and service-friendly. We offer the same material combinations, so you get a solution that matches both the medium and process requirements.  

For left directional pumps, we have a similar version with a low seat and open design. Here too, you get a carbon slide ring and a stationary part in stainless steel or silicon carbide. You can choose between EPDM and NBR, depending on how often you clean and which media run in the line. 

The material composition of sealing surfaces and gaskets has a direct impact on service life, chemical resistance, and thermal stability. On the Fristam variants, the rotating part is available in carbon or silicon carbide, while the stationary part is available in stainless steel or silicon carbide, depending on the medium and wear profile. The seal materials are made of EPDM, NBR, or viton, so the seal can be adapted to water-based, fatty, and chemically aggressive media. This flexibility ensures that the seals can be used widely in both food and pharmaceutical production while complying with the hygiene standards that characterize Fristam pumps' construction. 

Proper installation and maintenance are important for the seal to function correctly. During replacement, o-rings and springs should always be replaced with new components to maintain optimal tightness. Over time, heat, pressure, and cleaning chemicals can affect the properties of the elastomer, so preventive service is recommended as part of scheduled maintenance. Our team is always available to provide advice to help you find the right solution for your plant and process conditions. 

In applications with high hygiene requirements, the mechanical seal protects both the end product and the equipment from contamination and the ingress of foreign objects. 

Yes, the materials used are suitable for contact with food and can be supplied with documentation in accordance with applicable standards.

You should inspect the seal regularly, replace o-rings and rotating parts at signs of wear, and follow the recommended intervals for cleaning and inspection.  

Silicon carbide is recommended for high-pressure operation or when handling media containing particles, chemicals, or highly aggressive cleaning agents. The material is characterized by its high wear resistance and chemical resistance, making it particularly suitable for demanding process conditions. Carbon, on the other hand, is a good choice for water-based or less demanding applications where low friction and stable sealing are more important than maximum hardness.