The OAMCU series is a pump-up high load platform using a passive system which eliminates frequencies down to 3.5hz and can support a maximum load of 1000kg. Built in air isolators have a natural frequency of around 3.5Hz at 150kg. The air isolation height is only 60mm, and the isolators are built into a frame. The casing is a stainless steel box with a depth of 80mm, total height including feet is 100mm. The height when not inflated is 90mm total including the feet, the feet are 6mm deep. The dimensions of the platform are up to 1m x 1m x 100mm; however, slightly smaller dimensions may be preferred.
The platform can be installed directly on the ground underneath the instrument and is pumped up with a standard Schrader valve. There are four isolators under the platform, each one is pumped up via its own valve at the front, back, or sides (specify when ordering). The Schrader valves are located along opposite sides and set in 90mm from each end at a distance of 43mm down from the top. All four valves can be placed on one side - requested when ordering. The valves are set back 15mm from the sides, but generally we provide valve extenders to bring the valve stem out from the side to make it easier to inflate - the valve extenders are available in a range of lengths, so we can extend the valves from the sides so they protrude from 5mm.
As air isolators are used, the height will vary if the load is changed. The load should be placed onto the platform with it un-inflated and then pumped up until it floats. The platform does not needed to be floated to the full height, it just means that the isolation performance will be slightly less than when it is inflated to the correct height - the main thing is that they need to check it is floating at each corner away from the base. It can also be inflated beyond the 105mm's but the stability will decrease. Avoid inflating the platform beyond 110mm. If the load is changed when it is floating , then the air pressure may need to be adjusted - it depends on how much the load is changed by.
The platform looks like a SS box with 4 valves, and when pumped-up, it "floats". The maximum overall height is 100mm when inflated. 100mm to 105mm will given the optimal performance. This platform only needs to float a few millimetres off the ground.
The top tray is made from 240 DP stainless steel 304 grade and is of a seamless welded construction, the base tray is made from galvanised steel (stainless is an optional extra – additional charge).
The feet are not detachable as they hold the base plate on. They are black machined nylon disks (58mm diameter), like large washers with a central threaded hole that allows them to be screwed to projecting short threads emerging through holes in the base plate. This means they act both as a foot and a base plate fixer. They are designed to allow the table to sit securely on the floor without marking it and also makes it easier to move into position.
Installation is very simple - the platform weighs around 45kg, and it is simply placed in the correct location on the floor. If possible the instrument should be lowered onto the platform to prevent scratching the platform top. The work surface is tough and resistant to chemicals. Level the platform and inflate to optimal height, this will mean the platform is floating. Then the isolators are inflated until the platform floats away from the floor by around 5mm. Start by pumping up the isolators by pumping a bit into one, then the second, then third and then fourth and continue until all four float. Do not pump one up fully then the next as the load on the isolators would not be balanced in this situation. The platform should not be over-inflated. Over-inflation could cause damage to the instrument.
To avoid lifting all the weight on one isolator, increase the pressure in the isolators to roughly the required pressure (we can supply chart) and not inflate just one until it floats - as the pressure would then be much too high on one corner as it would be carrying twice the relevant load. If each isolator is pumped up to around the required pressure, then the final adjustments can be made to the pressure in each one to get the platform to float correctly. The pressures may not be exactly the same as they would depend on the position of the centre of gravity of the instrument. If this is not central then the loads on each isolator would vary.
These isolators are only lightly damped and may amplify frequencies close to 3.5Hz, however, they will give around 5x reduction of vibrations at around 10Hz.
We can also supply the OAMCU with higher load isolators which would give a natural frequency of around 5.5Hz at 150kg per isolator - but the isolation at 10Hz would be reduced.
We also offer the HiSpec range of isolators - these are much longer and have a natural frequency of 1.8Hz at this load and 1.3Hz for the high load version. They perform much better at 10Hz but slightly worse at 1 to 2Hz. These isolators are heavily damped, so do not produce much amplification at resonance. The HiSpec legs can either be passive (pump-up) types or active versions (which will require a source of compressed air up to 7 bar).
|Dimensions (LxWxD) (mm)
||Up to 1000x1000x100
|Level adjustment (mm)
||Pharma grade stainless steel
||4 off cushion air isolators (hand pumped via Schrader valve)
||50Hz - 95%
100Hz - 98%
Natural frequency 3 to 5Hz
||-20 to +160 deg. C
||~55kg depending on selected dimensions and options
Custom dimensions to match the footprint of an instrument are available - ask.