Equipment manufacturers are increasingly designing machinery to work faster with more precision, whilst reducing weight and cost.
Farrat Isolated Foundations are used in many applications to ensure the operating conditions in terms of vibration levels are controlled to within equipment specifications, to maximise productivity and conform to H&S and local authority requirements.
Whether you are relocating existing machinery, installing new equipment or are involved in detailing foundations, Farrat have the knowledge and experience to provide the right Isolated Foundation solution.
Farrat Isolated Foundations are designed to provide effective, low frequency isolation of machinery and equipment.
Used extensively in industrial applications either as Active Isolation to prevent noisy, vibration emitting equipment (power presses, printing presses etc) from disturbing their surroundings or as Passive Isolation to prevent sensitive equipment (body co-ordinate measuring machines, dynamometers etc) from being disturbed by structure born vibration.
What is the basic construction?
IFD’s consist of a concrete Inertia block, to which equipment or machinery is rigidly connected. Specialist Vibration Isolating Material provided by Farrat surrounds the Inertia block to prevent vibration either entering or leaving the Inertia block, depending upon the particular application.
What different configurations are there?
Although there are multiple variants, there are two main themes of Isolation: Full Isolation and Lateral Isolation.
With Full isolation, both base and walls of the Inertia block are surrounded with Isolating Material, whereas for Lateral Isolation only the walls are surrounded with Isolating Materials.
How does the Vibration Isolating Material work?
There are specific material properties that are determined by specialist in-house Test equipment at Farrat that allow us to determine the Transmissibility.
This is also affected by the exciting frequency, natural frequency, mass, isolation efficiency given under load conditions, etc.
What does the Inertia block do?
The Inertia block has several advantages:
- The inertia block adds mass, which significantly reduces the vibration levels relative to the vibratory force. This is known as ‘Mass Damping’.
- The inertia block adds stiffness, thus maintaining alignment during changes in static and dynamic loads. This can be particularly beneficial for long bed machinery, or high precision equipment.
- The inertia block also reduces the Centre of Gravity (COG), which can be very beneficial for equipment with a high COG.
- Farrat can provide guidance when determining the Inertia block size for a particular application.
Example Construction of Farrat Isolated Foundation
Typical Isolated Foundation Configurations
There are two main types of Vibration Isolation systems, Full Isolation (Base and Walls) and Lateral Isolation (Walls only). Elastomeric Isolation elements, Foundation Isolation material and coil spring isolators are all commonly used as isolation elements under isolated foundations and inertia blocks.
Full Isolation (ISOMAT System)
This system is typical where Vibration Isolation is paramount, and therefore requires isolation from the base of the inertia block in addition to the walls (Fig 1.0). There are a variety of construction types, depending on the application, construction and budget constraints.
This system has several construction variants:
- Type 1 – For Inertia blocks greater than 1m high using Farrat ISOMAT pads. (Fig 2.0)
- Type 2 – For Inertia blocks less than 1m high using Farrat ISOMAT pads. (Fig 3.0)
- Type 3 – For Inertia blocks requiring full area support. (Fig 4.0)
- Type 4 – Box in Box System
This system is typical where a high stiffness foundation is critical but a degree of active or passive isolation is required, even if only from the risk of random events such as accidently dropped heavy items nearby.
- It is advised that Lateral Vibration is incorporated between the sidewalls of the foundation block and the surrounding structure.
- Farrat ISOFOAM is the main material for Lateral Isolation, with Farrat Vidam and Voidfiller also used depending upon application.
- Typical applications include Dynamic Test Rigs and large Machining Centres.(See Fig 5.0).
Spring Isolator System
This system is most suitable for Inertia blocks requiring spring isolators (integrating viscous dampers if required).
Each Farrat Isolated Foundation system will combine the use of; high performance vibration isolation materials, mass damping, and rigid, uniform fixing of the equipment to its foundation. For more information on which system is most suited to your application, please request a copy of our Farrat Technical Brochure or download one of our Application Guides.
ISOMAT Pads Farrat ISOMAT Foundation Isolators are the cornerstone of Farrat’s Isolated Foundation Solutions. Our ISOMAT pads have a unique profile coupled with a selection of our elastomers and thicknesses. Due to extensive testing and experience, ISOMAT pads deliver highly predictable performance characteristics over many years of service. Farrat ISOMAT is produced in 3 elastomeric types: IMBR, IMCR and IMNR. Please refer to our latest material datasheets for details on material characteristics:
ISOMAT Pad Properties & Damping
|IMBR||Nitrile||Excellent combinations of elasticity, oil resistance and high damping.||-||-||-||9%||10%|
|IMCR||Neoprene||High elasticity, moderate damping and good oil and chemical resistance.||-||-||5%||-||-|
|IMNR||Natural Rubber||Maximum elasticity and low damping (passive isolation). Poor oil and chemical resistance.||-||2%||-||3%||-|
FSL & FSLV Spring Isolators
Where natural frequencies are required below 7Hz (limitation of elastomeric materials), then Farrat’s standard range of spring Isolators and dampers allow natural frequencies as low as 3.2Hz to be achieved. Farrat also design bespoke spring units for specific requirements, and for frequencies lower than 3.2Hz.
Farrat’s range of heavy duty structural coil spring isolation systems provides low frequency vibration isolation for large structures and industrial equipment. They have been used worldwide for a wide range of applications.
Farrat FSL Coil Spring Isolation systems are used to provide both active and passive vibration isolation with natural frequencies down to 3Hz to isolate disturbing frequencies down to 6Hz.
Where a system is likely to pass through or near resonance or shock vibration is encountered then it is recommended that the FSLV products are used, which incorporate a viscous damping unit.
The standard Farrat Spring Isolator range includes:
|Un-damped||Damped||Length (mm)||Width (mm)||Spring rate (kN/mm)||Max Load per unit||Min Load per unit|
|FSL1-8||FSLV1-4||940 (FSL) 850 (FSLV)||305||6.8||170||56|
Full Area Matting
Farrat’s wide range of full area isolation materials cover a wide spectrum of performance and price, covered by 4 material grades and 3 standard thicknesses of 12.5mm, 25mm, and 50mm.
Three of the material grades are Farrat Verlimber, which is a range of high grade vibration isolation, high quality polyurethane using an innovative blown expansion method. The three grades offer a wide choice of performance and thickness, ensuring the most cost effective solution, and are used where the high levels of isolation are required.
The remaining material is Farrat Favim which is a medium performance, cost effective material manufactured from high quality recycled rubber and foam granulate with polyurethane bonding agent.
Farrat Favim has been used for many years in general industrial workshop environments.
Although these are classed as ‘Full area’ materials, we do also provide the Verlimber as pad design, due to their high load capacity.
- Bodymakers and Cupping Presses
- Precision Machinery
- Rotary Presses
- Grinding Machines
- Pumps and Compressors
- Fans and Turbines
- Dynamic Test Rigs
- Canning & Steel
- Steel / Paper
- Oil & Gas
- Power Generation
For Lateral Isolation, Farrat have several materials available as detailed in section 4 above. If in doubt please contact Farrat Technical.
For Full Isolation, the key factors for vibration isolation are:
1. Total static Mass, including tool and component mass
2. Dimensions and mass of Inertia block
3. Required Dynamic Natural frequency
4. AV Materials and Products above
The first two points can generally be determined quite easily, and Farrat can advise on the most suitable damping levels /materials for given applications. Other factors to consider are the environmental compatibility, particularly the compatibility of the isolating materials with oils / lubricants, etc.
The Vibration Isolation for Cyclical Vibration is dependent on the ratio of exciting to natural frequency, so is relatively easy to determine the required natural frequency for a required level of isolation.
For the isolation of Impact machinery, the theory is more complex, as there are many more variables and we would advise contacting Farrat Technical team to discuss your application / requirements.
Vibration Isolation reduces the level of vibration transmitted to or from a machine, building or structure from another source.
Vibration can come from multiple sources, such as; imbalance of rotating machinery, impact from a metal stamping press, reciprocating engines and compressors which have inherent imbalance. When sensitive equipment requires isolating even low levels of vibration from sources such as overhead cranes, stacker trucks and accidental dropping of heavy objects, can become a problem.
Vibration Isolation is a very complex subject, particularly when the non-linear properties of elastomers are taken into account. Therefore, solutions are derived by using a combination of theory, knowledge and practical experience.
Generally there are two main sources of vibration, these being Cyclical and Impact.
Refer to brochure for further information on cyclical and impact vibration.
Fig. 1.0 Transmissibility Curve
GE Energy Type: Isolated Foundations
Stolle, Germany Type: Isolated Foundations
Kaleva Printing, Finland Type: Isolated Foundations
BAE, Samlesbury Type: Isolated Foundations
Why choose Farrat for Isolated Foundations?
Farrat have been designing Isolated Foundations and supplying Isolating materials globally, for over 50 years across multiple industries. Constantly driven by Engineering Excellence, Farrat continue to lead the way at the forefront of development in the IFD market by continuously investing in R&D, with strong associations with Universities.
- Creative Engineering We have both the theoretical knowledge of vibration isolation and practical experience of how to achieve the required vibration isolation / damping across various applications to ensure we provide the most cost effective solutions to clients.
- Quality Assurance Farrat Isolevel Limited operates an ISO 9001:2008 quality assurance system and ISO 14001:2004 Environmental Management Standard.
To effectively process an enquiry we ask for you to supply the following information on the machine/structure to be isolated:
- Length, width and depth of machine and/or proposed foundation pit / inertia block
- Static Wet Mass
- Mass of any workpiece components, tooling or general live loads in addition to the Static Wet Mass
- Previously determined natural frequency required by the isolated foundation system
- Type and grade of any pre specified vibration isolation system / materials
- Drawings of the installation, layout and machine / structure to be isolated
- Location of the installation.
*ideally in Excel format, provided as Dead Load, Super-imposed dead Load and Live Load with location plan drawings. **We will consider horizontal loadings, but only once the vertical bearings have been designed.