Mariotti & Pecini are the leading manufacturer of agitators in Italy and among the best in EU. We manufacture all types - top, side, bottom mounted versions with mechanical seals and magnetic driven seal-less units. Our best known brand is Magna-SafeTM models MST, MSE and MSB using magnetic torque. Over the past 25 years of dedicated service to industry, we have a large & respected customer base in EU & USA. There are over 40,000 units supplied by us world wide.

Construction features & Advantages

Magna-SafeTM uses state-of-the-art technology and engineering practice. The magnetic flux is robust and expected to last for years. In magnetic drives the mixer shaft does not pierce through the vessel consequently there is no question of shaft-vessel interface- ie sealing devices like mechanical seals are eliminated. The most important construction feature is the mixing head. It consists of very powerful magnets encased in SS 316L cover and hermetically sealed using laser technology. On this the specially profiled shaft and impeller are mounted; blades dimensions vary depending on the vessel size and duty conditiions. In MSB models the mixing head is suspended around a Silicon carbide bush so that it rotates easily free of friction and particle generation. In MSE models the extended shaft are suspended on SS-ceramic hybrid bearings.

Advantages

The high technology features of Mariotti & Pecini design render following advantages:

• Containment – no contamination, no emission, no sealing problems

• No abrasion or wear and tear – virtually maintenance free operations

• Dry running – with hybrid bearings (used in extended shaft design) dry running is safe

• Bottom mounting – helps better turn down ratios (low vol operation), saves head room

• RPM – variable speed control using VFDs is built in

• CIP/SIP/sterility – good surface finish and profile for cleanability, sterility and easy maint.

• Autoclavable – small vessels with mixers can be autoclaved, no problem
  

These point to the most important overall advantage viz total integrity of the vessel without leakage or possibility of sterility challenge either of the vessel or it’s contents - extremely crucial for sterile processes encountered in pharmaceutical and biotech industry. Additionally, there is ease of dismantling, no mech seal coolant failures or seal face replacements, low operating volumes (near empty situation), surface finish meeting stringent pharma cGMP requirements. The systems is completely CIP’ able and SIP’ able). Impeller profile and body contour ensure total and quick draining during CIP runs due to centrifugal force (radial throw).

Superiority of Components used

There are six major parts for Magna-SafeTM magnetic agitators.

Parts located inside the vessel are mixing head/shaft and impeller, male bush/bearing plus weld flange which is welded on the vessel

Parts located outside the vessel are Gearbox, motor and Drive magnet

Components

Magnetic Coupling - Permanent magnets of SAMARIUM COBALT, rare earth for permanent magnets of very high gauss that generate magnetic torque for mixing without slip.

Bushing - Silicon Carbide-Silicon Carbide

For MSB mixing head design, we provide the female bushing in Silicon Carbide. The MOC and finish are extremely critical. For the pH operating range normally encountered in pharmaceutical and biotech processes (3.0 to 11.0) the best material in our opinion is Silicon Carbide of which we use of special quality and surface finish to prevent particle shedding. Tungsten Carbide bushings (offered by many competion companies) which are inferior and we do not recommend its usage.

Magna-SafeTM mixers have been tested by third party inspection teams for particle emission and have been fully cleared; pl refer to Silliker Labs, USA test report. (similar report is available on CIP test done)

Bearings - Hybrid – AISI 316L coated Ceramic balls

For extended shaft design MSE and top drives MST, we provide double SS -Ceramic hybrid bearings. Our unique self supporting extended shaft design is superior to top bush/lock nut version offered by other makers. Our hybrid bearings are forgiving hence even if the agitator runs dry when vessel is empty there is no damage to the unit which is impossible to achieve with bushings.

Impellers - Pitched blade, Ruston turbine, paddle, anchor, marine propeller

Depending on application like mild to moderate liquid-liquid mixing we suggest paddles or pitched blade impellers, especially for shear sensitive mammalian cell cultivation. We recommend slightly higher diameter and lower RPM in such cases. In case of microbial fermentation vessels we have Ruston turbine options for achieving better aeration and OTR. Max speed restriction if necessary can go up 10 to 20% higher rpm will not adversely affect the mixer performance, life or safety.

Surface finish

All contact parts will be polished Ra < 0.5 microns smoothness meeting fully the stringent cGMP, CIP’able and Sterility norms. To us functionality and operational ease are paramount so as to our customers. Therefore we ensure that our mixers deliver the best value and versatility.

Performance efficiency and guarantee

Mixing operations

Bottom and top driven magnetic mixers are designed for use at various rpm to achieve vigorous agitation or gentle mixing. The rpm can be controlled using a VFD (variable frequency drive) unit through which power to motor is controlled. On a linear scale desired rpm can be attained by varying the frequency in 3 phase in-put with restriction to a lower limit of 50 rpm.

Energy efficiency

Mariotti-Pecini’s systems are designed well. Choosing the right profile for desired application, we demonstrate energy efficiency during operations. For example in a 3000 litre fermentor vessel, bottom driven magnetic agitator requires only a 1.5 to 2.2 kW motor depending on dia/media. Long hours of fermentation batch runs can gain power savings and lower operation cost.

Process efficiency

• Blending / Mixing - general liquid-liquid mixing or vigorous agitation to incorporate air

• Optimal shear – ensures no shear force exerted on culture and no damage to cell walls

• Suspended solids – mixer will ensure uniform distribution of solids in liquid phase

• Heat transfer – efficient distribution heat flux input from/to jacket through tank wall

• Gas dispersion – fine dispersion and mass transfer minimising bubble size for O2/CO2

Overall our mixing system ensures that temperature is uniform level, mixing profile good, process characteristics for critical application like cell culture (vulnerability to shear) are maintained

CIP Protocol with MSB model Magnetic Mixers

Introduction

Mariotti & Pecini are the leading manufacturer of agitators in Italy and among the best in the EU. We manufacture top, side, and bottom mounted versions with mechanical seals and magnetic driven seal-less units. Our best known brand is Magna-SafeTM magnetic mixers - MST, MSE and MSB - using rare earth magnets. In the past 25 years of dedicated service to industry, there are over 40,000 units working world wide of power rating from 0.25 kW to 300kW.

Features of contact parts in MSB models

MSB uses state-of-the-art technology and engineering practice. The most important aspect of cleanability is the execution method for contact parts viz mixing head, SiC bush and weld flange. The mixing head consists of high gauss cylindrical magnets encased in SS 316L cover and totally sealed using laser welding technology. The impeller blades are welded to the SS encased magnet. Mixing head is mounted on the SiC bush rotates freely. There is no other dynamic contact part for the impeller and rotation is almost frictionless (in custom designed models MSE & MST hybrid bearings are used, not bush. The weld flange (tank plate) is welded to bottom dish end of vessel. All contact parts will be polished Ra < 0.5 microns smoothness meeting cGMP & FDA norms

Drainability, Cleanability & Sterility

There are many parts for Mariotti-Pecini’s MSB magnetic agitator systems. Parts located inside the vessel are mixing head and impeller, male bush mounting & weld flange welded to vessel (also called tank plate). CIP/ SIP advantages are:

• No retainment – all contact parts are smoothly contoured without crevices

• No particles – virtually friction free operation hence no particle generation

• Weldflange – profiled to integrate well with bottom dish end seamlessly

• Impellers – orientation and finish ensures forceful throw of CIP fluid

• CIP - profile of mixing head and SiC bush ensures total cleanability

• SIP – sterilisation or autoclave can be done without sterility challenges
  

In other words, total integrity of vessel is assured after CIP without leakage or possibility of any sterility challenges due to our magnetic mixers.

Suggested CIP protocol

Below is a suggested CIP protocol - It is only a well meaning suggestion, please appreciate we do not take any responsibility over the results obtained.

Recipe & Operation

The choice of cleaning fluid and it’s temperature is decided depending on application or products made. In most cases RO (can use DM water also) water at 50-60°C should meet the requirements. After the production batch is drained from vessel, first clean with normal water followed by hot water. Each time mix with magnetic agitator for 5 minutes and drain water off. Check residual ppm of product in water; the process is repeated till 6 ppm level or lower is obtained. Then conduct a swab test at the vessel discharge. In an area of 5 x 5 sq cm swab both ways - along and across - using sterile cotton swab; then analyse for residual ppm levels (max 6 ppm permitted) Alternately Extran MA02 can be used as per Merck’s standardisation for usage and procedures for cleaning (presence of Extran can be determined by the method provided)

CIP

The CIP cycle for vessel cleaning may be suggested as below. Cycles, recipe and cycle time is decided by individual companies depending on application/products.

• RO water rinse (covered above)

• Alkaline rinse

• Hot RO water rinse

• Acid rinse

• Hot RO water rinse

• WFI rinse
  

The final WFI rinse is done only after the conductivity reading on the electrode mounted on the vessel discharge matches the preset value (to ensure absence of alkaline/acidic trace)

We assure that our mixers deliver the best value in terms of versatility & durability. Our representatives TurbuLens Technologies, Bangalore (info@turbulens.in) are available for any help / assistance or guidance.