When it comes to choosing heavy lifting equipment for lifting smooth and fragile natural stones, such as polished slate or cut marble, conventional lifting clamps may not cut the mustard. Vacuum powered lifts, however, specialise in lifting these awkward objects, and there are a wide range of vacuum lifts available on the heavy lifting equipment purchase and hire market. However, not every lift is suitable for every job, and you should familiarise yourself with the different types of vacuum lifts available so you can choose the most suitable one for your needs.
The first choice to make when looking for stone vacuum lifters is whether to opt for a powered or unpowered model. Each types has its own advantages and disadvantages:
- Powered vacuum lifts generally cost more to purchase or hire but are capable of tolerating much heavier loads. The vast majority of winch or crane-mounted vacuum lifts are powered, and these robust pieces of equipment are capable of lifting heavy industrial-scale loads. Alternatively, battery-powered handheld models can be utilised for smaller loads.
- Unpowered vacuum lifts function in a similar fashion to a bathroom plunger, but don't let the strange mental image put you off. These systems can be remarkably efficient and are less expensive and less likely to encounter mechanical failures than powered models. However, their lifting strength is obviously quite limited. Some unpowered models achieve vacuum by drawing air out of the suction cup as the lift is raised, while others include band pumps to manually remove air from the cup.
Choosing your cups
Lifting the smooth surface of cut stone requires a vacuum cup with a completely airtight seal that will not slip around on the surface of the stone during movement. You should also pay attention to cup configuration; single, large suction cups and pads are less complex and expensive, and are suited to moving large, regularly shaped blocks of stone. Multiple-cup models are more well suited to moving irregularly shaped or particularly fragile stones and also provide adequate redundancies in case of vacuum failure. For highly irregular loads, consider purchasing a multiple-cup system with flexible connectors.
Lifting any large load obviously entails significant safety risk, and any vacuum lift you choose should be accompanied by the following safety equipment:
- Low vacuum alarm: These should ideally be both audio and visual.
- Vacuum cup storage cases: The rubbers and polymers that many vacuum cups are made from tend to perish under direct sunlight and can also be damaged by excessive moisture. Keeping them in watertight cases or holsters will extend their safe working lifespan.
- Resting trestles: These simple structures are fitted to the edges of your lift's vacuum cup, and prevent the relatively fragile cup from being damaged by ground contact.