Safety of Pfaudler mechanical seal components

06 August 2017

Safety of Pfaudler mechanical seal components

Mechanical Seal Systems for Glass-lined Reactors 

Glass-lined reactors play an outstanding role in the modern chemical and pharmaceutical industry, when processes demand the highest requirements from the corrosion resistance of the reactor materials or from the cleaning ability of systems and equipment. In such production plants, process and environmental safety is always ranked first. These safety requirements must be met by all the components of a glass-lined reactor. The mechanical seal, as a dynamic seal of the agitator shaft to the vessel, plays an important role as a safety-relevant and safety-determining component. 

As the process requirements differ from case to case, Pfaudler has developed a flexible modular system of mechanical seals, which can cover most applications. The fleXeal mechanical seal system by Pfaudler includes the following seal types:

Wet running seal - fleXeal UF8

A sealing liquid assembly generates a counter pressure in the mechanical seal. The hydraulic pressure and the spring force press the rotating, axially movable primary rings to the mating rings. Lubrication takes place by means of the sealing liquid. A very thin lubricating film in the sealing gap minimises wear. The cooling of the mechanical seals to DIN is achieved by the integrated cooling jacket or optionally by a thermosiphon. Sealing liquids, oil, white oil, demineralised water, alcohol.

Dry running seal with contact - fleXeal BF7

The function of dry-running mechanical seals with contact is based on the self-lubricating properties of the seal materials. The sealing space is filled with a sealing gas (nitrogen). A new, FDA-compliant dry-running carbon material ensures a long life with minimum sealing gas leakage, even without moistening of the sealing gas.

Gas-lubricated, non-contacting dry running seal - fleXeal GF7

The principle underlying this type of mechanical seal is directly derived from fast-running non-contacting mechanical seals for pumps and compressors. In order to achieve contact-free operation, the rings are grooved. The sealing gas entering the grooves together with effects of gas dynamics produce a thin aerodynamic gas cushion on which the mating rings "float“. To minimise wear during start-up, the mating rings are equipped with a very hard diamond-type surface finish. In order to minimise the sealing gas consumption, the fleXeal GF 7 mechanical seal may also be equipped with a dry running pair of primary/mating rings with contact on the atmosphere side. The sealing gap on the product side can be adjusted to a constant value by using an active regulator. The fleXeal GF7 mechanical seal is the ideal design for all applications where highly pure products are crucial – without any wear particles or sealing liquid contamination. Pharmaceutical (FDA/GMP requirements) and fine chemical applications can be easily met.

All Pfaudler fleXeal mechanical seals are double-acting products. They consist of two sets of primary/mating rings. In addition, a separate emergency seal is provided and takes effect upon failure of the sealing pressure (reverse pressure principle). Due to a ceramic sleeve, the pressure test can be performed without an agitator shaft. Cooling and sealing functions can be separated by an integrated cooling jacket. Cooling is also guaranteed if the seal runs dry. 

Pfaudler fleXeal mechanical seals are preferably designed for glass-lined reactors to DIN 28136 with top-mounted drive for a shaft end diameter from 40 mm up to 160 mm to DIN 28159 and agitator flanges to DIN 28137-2. All seals are equipped with an integrated bearing, so they serve as agitator shaft bearing. Their metal-free product side makes them optimally suited for the application ranges of glass-lined reactors.

The Pfaudler fleXeal Ultra Clean series offers the optimum solution for pharmaceutical and sterile applications. It is designed for GMP-compliant production away from the well-known DIN designs. The seals come along in connection with a pad flange at the reactor top. The sealing ring set of the product side is running inside the reactor. This allows for a short design, a sealing gap free for inspection, easy to clean. The use of FDA-approved materials guarantees suitability for sterilisation and CIP processes.

The comprehensive Pfaudler accessory range ensures the individual adaption of the fleXeal mechanical seals to specific requirements. Pfaudler offers the full range of seal supply systems. Static sealing pressure system for generating the sealing pressure of wet running mechanical seals, for oily sealing liquids. Thermosiphon system with different design variants, e.g. cooling system, manual refilling unit, level indicator, recirculating pumps. Gas panels for connection to the sealing gas source. For monitoring and adjusting the gas consumption and sealing gas pressure of dry-running and gas film lubricated mechanical seals.

The Pfaudler fleXeal sealing solutions provide a further increase in operational reliability, longer life, less maintenance and effective operation. The mechanical seals are highly flexible in practical use through a modular system.

Pfaudler also offers full service for glass-lined reactors. Our service technicians are familiar with the assembly/ disassembly of agitator drives and any kind of mechanical seal systems. The Pfaudler service canters provide mechanical seal inspection and repair of seals. Most of the fleXeal series are kept in stock and can be delivered in a short time – including spare parts. 

Contact Pfaudler today to learn more

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