Hydraulic ram pumps and Sling Pumps

figure 5.26After two days you can remove the support poles from inside the tank and start plastering the domefrom the inside. This plaster is mainly to cover the sags and the reinforcement and is not supposedto be entirely smooth. But it is important that all reinforcement still visible is covered by at least 10mm plaster. Remember water in the tank will evaporate and condense inside the roof. Thecondensation creates corrosion of the reinforcement if it is not properly covered with cement mortar.While plastering cut a piece of galvanized gauze wire overlapping all sides of the overflow openingby 30 mm. Fix it in position with binding wire from inside, then plaster on top of the overlap, keepingthe overflow opening uncovered, Fig. 5.27. If you need a scaffold inside the tank to reach the domefor plastering, make sure it does not damage the floor plaster. Always put straight timber boardingunderneath the scaffold. After the roof plaster is finished, remove everything from inside the tankand clean the floor, using a broom -if available a wire broom. It is very important to clean the floor aswell as possible. If there are marks or holes in the floor plaster, patch them with a 1: 3 mixture. Nextprepare a mixture like nil, but add one part fine sand (two parts cement, one part fine sand) andwater. The consistency should be slightly stiffer than the nil coat you used for the wall. Plaster thismixture on the floor inside the tank using a rectangular steel trowel. After you have finished the lastcoat, set the floor under water. However, use the water carefully Do not pour a bucket of water onthe floor from the manhole. The water will spoil the smooth surface. If you have a hose, put the endon the bottom of the floor and open the tap. If a hose is not available, take a timber board covered atone end with some cloth, and place this end carefully on the floor through the manhole. The upperend must lean on the edge of the manhole. Then take a bucket of water and pour it along the boardslowly, so that it runs down to the bottom. Repeat this until the floor is covered with water. After themanhole cover has been inserted, the reservoir isready. Downpipes should be connected but, before thecrew leaves the site, water must be filled into thereservoir up to a level of at least 100 mm.44