Industries which use submersible pumps for pumping out water etc. For deep underground, prescription need special equipment to lower and to retrieve the pumps, see which are often left in place for some time.
Because the pumps are situated at depth, malady an extremely tall framework/gantry and long length of standard chain would be needed to lower and lift the pump, this is just not feasible.
A specialist type of chain, known as a pump lifting chain, is produced specifically for this purpose. Why is it different? Because of the often wet conditions in which they are used, stainless steel is usually the only option, in which these chains are made, in either grade 80 or grade 316 stainless steel, although grade 80 high tensile steel is also available for less demanding conditions. The chain is also available in various link sizes with various capacity ratings to suit different sizes of pumps.
The chain is predominantly different due to the fact that at every one meter increment there is a larger master link to allow it to be fitted onto the hoisting device at 1 metre intervals, it is a slow process, but it is the only safe way to retrieve a submersible pump.
How does it work? A frame or tri pod system is placed over the hole in which the pump is submerged, then the first master link on the pump chain is fitted to the hoisting device, this is then raised to usually when the third big link is level with the top of the hole, then a pole/bar is passed through the link and supported over the hole itself, this will give you some slack on the top master link, so you can easily remove it from the hoist. The hoist will then be lowered back down to the second link, (just above the 3rd link with the bar through) the bar is removed and then the hoist is raised a little more, this process continues until the pump can be accessed or removed. It is a slow process but it is the only method that works successfully.