Magnetic Rotary Feedthroughs

AFS are world leaders in Smart Fluids. They offer a range of integrated sealing solutions for the introduction of rotary motion where a vacuum or low pressure is present.

Magnetic Fluid O-Rings around a rotating shaft provide hermetic sealing with zero leakage, no particulate generation and minimal wear. Ferrotec feedthroughs are precision engineered components with standard international and custom flanges available.

Advantages of Magnetic Fluid Sealing

Negligible leakage (typically <1.0 x 10 ¯10 standard cc helium/sec.)

Extensive life - A life of 3 years or more is typical, depending on process.

Wide speed range - Maximum speed is dependant on shaft size, radial and thrust loads.

Non contaminating - It is a characteristic of magnetic fluid that non-magnetic particles are actively rejected and gases are effectively sealed, making it virtually impossible for them to pass through the magnetic fluid.

Optimal torque transmission - Provides much higher torque capability than magnetically coupled feedthrough designs.

Exclusion sealing - provides exclusion to particle or other contaminants in critical sealing applications.

Magnetic Fluid Sealing Technology

Principles of Operation

A magnetic fluid rotary seal uses a permanent magnet and "teeth" cut either on the shaft, or occasionally, on the stationary pole-piece to create a localised magnetic field gradient in a small radial gap between the shaft's teeth and the stationary pole-piece. Magnetic fluid is drawn into this gap and held in place by the magnetic forces - in practice the fluid forms a hermetically sealing liquid o-ring seal above the tooth.

The "captured" magnetic fluid will resist any attempts to move it from this gap and will therefore sustain a pressure differential. Typically, one "tooth" will sustain a pressure differential of around 0.2 atmospheres so sets of teeth are used to provide the required pressure differential. For vacuum systems, Ferrotec 's feedthroughs are designed with a minimum 2 atmospheres capability to ensure an adequate safety factor.

Benefits of Technology

High Vacuum Operation - advanced magnetic fluid formulations mean that vacuums up to 10-9 mbar or better can be achieved.

Leak free Operation - magnetic fluid feedthroughs seal virtually hermetically, leak rates of 1.0 x 10-11 mbar I/sec or better are routinely achieved.

Positive Pressure capability - feedthroughs also have a minimum positive pressure capability of 2 atmospheres, with higher pressures possible with minor design changes.

Optimum Torque Transmission - the use of liquid o-ring seals give low friction, slip-stick free rotation, high torque transmission and a large speed range from indexing to many thousands of rev/min.

Non Contaminating - the sealing element is non-rubbing and so no particles are generated and the seals are ideal for ultra clean environments.

Long Life and High Reliability - the sealing medium is a low vapor pressure fluid, friction is very low and wear insubstantial. Seals can therefore have exceptionally long lives, with maintenance free lives of over a decade being recorded.

Improving Equipment Uptime

Let Advanced Fluid Systems Keep Your Feedthrough "Like New"

All Makes of Feedthrough Serviced
Same Day Service Available
Feedthrough Exchange Available

Unfortunately, it's a fact that even the best feedthrough or Drivethru™ can fail. Don't let bearing break-up, contamination of magnetic fluid or other maintenance issues interrupt your production line. Ferrotec will repair your feedthrough quickly and inexpensively using state-of-the-art magnetic fluid and high quality, precision bearings.

Our experienced technicians will evaluate and repair your feedthrough

Fast track inspection and repair includes:

Disassembly for comprehensive inspection and evaluation
Thorough cleaning of all parts
Rebuilding with new bearings, o-rings and Ferrotec's state-of-the-art magnetic fluid
Bearings fully run in
Leak checking, both statically and at process speed

If we find significant damage requiring more extensive repair work, we provide:

A detailed description of the work needed
A list of recommended replacement parts
A full cost disclosure

You decide. No work will begin without your approval

We can guarantee Repair of other Manufacturers Products

Ferrotec is at the forefront of feedthrough design and manufacture worldwide. Because of our extensive technical expertise, we can repair all makes and models of feedthrough. In most cases, our technicians can improve the life expectancy of any other manufacturers' feedthroughs.

Set Up a Contract for Preventative Maintenance

We can help you set up a maintenance schedule that will prevent costly downtime. We will tailor a program to suit your particular situation, for example:
Periodic inspection and feedthrough rebuilding to maintain your system. We will replace magnetic fluid and fit new bearings.
Timely testing of feedthroughs running at high temperatures or in contaminated environments.
Detailed record keeping of each feedthrough's life and performance to date

Take Advantage of Our Feedthrough Exchange Service

For your convenience, we can supply a fullly repaired and warranted* feedthrough to you while yours is being repaired. Contact us for full details.
* warranted as new

Feedthroughs with Bellows

For compliantly mounted feedthroughs movement is minimal and it is often unnecessary to change the bellows unless they are leaking. For linear motion feedthroughs, the bellows undergo considerable movement and we recommend changing these bellows when the feedthrough is repaired.

Contact Ferrotec for details of all our maintenance programs and for full information regarding how to ship your feedthrough and what documentation to include. Our technicians are always available to answer specific questions.