VIBRATION ISOLATION PRODUCTS
- Professional microscope antivibration tables
Creating the best environment for microscopyOverview
Vibrations limit the performance of sensitive instruments in numerous applications. Thus the need to remove vibrations to optimise performance has become crucial. We have spent many years developing state-of-the-art workstations and platforms, which provide the user with a truly vibration free surface on which the user can place equipment. Our products are available in a wide range of sizes and shapes to support instruments of varying weights and footprints.Features
- 2Hz natural frequency built-in air isolators
- Active self-levelling and passive pump up versions
- Highly rigid laminated construction with damping core
- Low cost, easy to install and free from maintenance
- Ideal for laboratories and clean rooms, will meet Class 10 (Class 1 available)
- Simple, compact, easy to use and clean
- Wide range of sizes, options and accessories
- Applications include: Microscopes, balances, interferometers and semi-conductor test and inspection
Elimination of movements from a working surface is achieved by isolating it from any external influences such as the floor and the structure itself is rigid and damps out any induced surface movements (fans etc.). The major sources of external disturbances are vertical and horizontal floor movements.
Floor vibrations arise from many sources; road traffic, trains, large machinery, lifts and building sway are among common examples. Typically building vibrations peak in the region of 7 Hz, however a metal frame building of height H has a resonance of roughly 46/H hertz, which means that on the fifth floor of a building you can expect horizontal and vertical displacements as low as 3 hertz. Floors almost never exhibit periodic vibrations in the 1 to 3Hz band.
The measure of the effectiveness of an isolation system is given by its transmissibility (opposite). As an approximate rule isolators start to become effective at between two to three times their own natural resonant frequency. Thus to remove vibrations at 7Hz an isolator with a natural frequency of about 2Hz is required.
The performance of an isolator depends on its stiffness and the mass it is supporting. In general isolator performance improves as mass is increased and for optimum performance one should work close to the maximum load an isolation system is designed to support. As an example, it is bad practice to place a 50kg load on a table designed to support 500kg, whereas a load of 200kg or more would be suitable.
The load supported by an isolator is calculated by multiplying the air pressure inside the isolator by the area of the piston it is supporting. Thus a piston of 15cm² surface area will support 25kg at 2 Bar. As (pressure) x (volume) for an isolator is a constant at any given temperature, increasing the load on an isolator will cause the piston to drop until the pressure has risen sufficiently to support the load. If one wishes to return the platform to its original level, then one must introduce more air into the isolator at the new pressure.
A self-levelling valve introduces and exhausts air automatically into an isolator and always keeps it at the same height.Construction
Our platforms combine a highly rigid damped table with an excellent vibration isolation system in one unique package.
It has long been accepted that the best isolation is achieved using pneumatic isolation chambers, which utilise high performance rolling diaphragms. All our isolators contain such a specially designed diaphragms.
Our isolators are also connected to a damping volume via a tuned restrictor. The restrictor absorbs system energy by converting air movements into heat as it is forced through the restrictor. This removes the overshoot and oscillations, which occur in isolators without dampening chambers and highly specialised restrictors such as ours.
We use a low isolation volume to damping volume ratio, which means that the working surface appears stiff to the touch (as all large low frequency disturbances are rapidly damped away). Small higher frequency disturbances are removed by the isolator chamber, these have a resonant frequency (dependant on version and load) typically in the range 1.5 to 2Hz. and whose characteristics are given in the transmissibility curves.
Our platforms feature a seamless steel top finished in either a grey epoxy powder coat or optionally made from dull polished stainless steel. Both finishes meet the Class 10 requirements. The stainless finish may be required in certain environments and we would be pleased to advise on this. The tops are formed by laminating a highly damping core between two steel plates using high strength aerospace grade adhesives, a technique we developed in producing our range of high performance optical tables and breadboards.
Four isolators, airflow restrictors and damping volumes are integrated into the platforms, which allow the working surface to float freely away from its base during operation. The natural frequency is typically 2Hz both vertically and horizontally and is suitable for all but the most sensitive instruments, where our low frequency option should be selected. We offer a choice of active and passive platform versions.
In active platforms, each isolator is connected to a self-levelling arm, which can be externally adjusted to set the height of the platform and level it. They should be chosen when the load on a table is expected to vary frequently. These platforms require a continuous supply of air. This can be provided by a compressor or using a gas bottle (suitable for months of normal operation and ideal for clean room uses).
Passive platforms are designed for applications where load does not vary. This includes balance tables, which are designed for light loads where the platform is weighted to give good performance.
Platforms are manufactured in one location using state-of-the-art automated machinery to guarantee high tolerances and consistency while keeping costs low. Our products are assembled by a highly skilled workforce and rigorous quality control is applied throughout the manufacturing process.Excellence in design
Great care has been taken in the design of our products to ensure they achieve the highest levels of performance, while being easy to use and to clean thoroughly. With isolation design optimised for use in microscopy and surface design optimised for easy of cleaning, our tables are ideal solutions for use in all areas of microscopy including cleanrooms and biohazard areas
A better working environment
- Excellent working environment
- Comfortable ergonomic design
- Pharma silicon stainless steel surface available
Our range of platforms and workstations improve the environment for your microscope with all the features necessary to make your work easier. Workstations provide a tailored working environment as well as featuring isolation built into the work surface, which makes working with a microscope both faster and easier, leading to more reliable measurements in your laboratory. Platforms are ultra thin and designed for use on benches beneath microscopes to maximise their performance.Vibration Control
The OAMF and OAMP platforms offer the ultimate performance, incorporating four 2Hz damped rolling diaphragm air isolators, efficiently isolating frequencies from 6Hz and upwards. The OAMS tables incorporate Sorbothane isolators, giving excellent isolation with a natural frequency of less than 7Hz. Our isolators considerably out perform both simple air cushion and rubber isolators, shortening stabilisation times and speeding up measurements. The OAMD-SA workstation has an active area top plate comprising a rigid top plate placed over a full size isolation table on which an active area plate freely floats for the instrument to sit on, giving the advantages the excellent stability a full size table offers, without compromising work space.Flexible solutions
We offer a range of workstations and platforms to suit different environments and microscope performance levels. Workstations feature a platform mounted on a study steel frame with height adjustable levelling feet and guards to protect the table from accidental knocks during use.
The ergonomic workstation design minimises user stress. With the active area option microscope platforms sit flush with the work surface and the surrounding area is useable for general work without disturbing measurements. Frames have height adjustable levelling feet, for excellent stability and user comfort with retractable castor feet, frame shelf and monitor support optional.
Selecting a platform
To select a platform you must first decide on the size of the working surface you require, the load it needs to support and the sensitivity of the equipment to vibrations; from this you can determine the class of product you require. You then need to decide whether you will require it to be floor mounted and what type of air supply would be best suited. We would be pleased to assist you and answer any questions you may have.
Active Platforms (OAMF series)
These platforms are self-levelling and ideal for use when loads on the platform are likely to change. They can support up to 160kg and are available in a range of standard sizes from 600 x 600mm up to 1500 x 900mm. Their low 60mm working height and low weight makes them ideal for use on desks and benches.Passive platforms (OAMP series)
These platforms are designed to be pumped-up and left alone. Simple to use, they are ideal for use with fixed loads or in applications where pressurised air or gas cannot be used. They support loads up to 160kg and sizes range from
600 x 600mm to 1500 x 900mm with a 60mm working height.Balance tables (OAMB series)
These passive platforms are weighted to 25kg and are for use with light instruments such as balances. They support loads to 120kg and are available in three sizes, 450 x 300mm, 400 x 500mm and 600 x 600mm. Their small footprint also makes them ideal for use when space is at a minimum. Working height is 60mm.
Contoured platform (OAMC series)
- High vibration isolation performance - ideal for 6 place balances
- Piump up air rolling diaphragm 2 Hz isolators
- Stainless steel or white epoxy finish, range of sizes
This light and compact passive platform has been specially designed for instruments such as microscopes. Its T- shape profile allows users to place their arms on either side of the platform while the width at the rear is large enough to support a wide range of instruments. Made entirely from electroless Nickel-plated aluminium parts it is suitable for Class 1 requirements. The top plate is 10mm thick with three damped isolators mounted to the underside.High load workstations (OAMH series)
These workstations are designed for heavy instruments such as electron microscopes, which require high degrees of isolation from vibrations. They comprise a highly rigid platform supported on a sturdy isolation frame fitted with levelling feet.
The platform is fabricated by laminating two 5mm thick ferromagnetic steel plates to a 50mm thick aluminium close cell honeycomb core using aerospace grade adhesives.
The resultant plate has excellent compliance characteristics and its rigidity is suitable for supporting large loads up to 1500kg.
The vibration isolators are built into the legs of the frame. Each leg contains a low natural frequency rolling diaphragm isolator connected to a damping volume via a tuned flow restrictor, giving a highly damped system with a natural resonance (at high load) of around 1.1Hz. The isolation system is active with a self-levelling arm attached to each leg allowing the platform to be levelled as required and to compensate for varying loads. The isolators are available in two versions, the standard version for loads up to 500kg and a heavy-duty version for loads to 1500kg. The standard platform is available in a range of sizes from 900 x 900mm to 1500 x 1200mm.Balance table workstations (OAMD series)
Balance tables (OAMS series)
- Flush table surface with isolation area
- Stainless steel or white epoxy finish
- 2Hz Air or Sorbothane isolation area / surface dampening
Anti-vibration platform applications
- Standard vibration isolation performance - ideal for 5 place balances
- Sorbothane rubber isolators and surface dampening
- Stainless steel or white epoxy finish, range of sizes