WATER HAMMER IN THE MAIN DRAINAGE INSTALLATIONS OF MINES WITH A LOW LIFT

Abstract

In accordance with the requirement of the Safety Rules, drainage installations of mines with a water supply height of more than 400 m must be equipped with means to prevent or extinguish water hammers. At the same time, the pressure in the injection pipelines during transient processes can reach a dangerous level and at a significantly lower water lift, especially but in mines with high water content, where parallel operation of several pumps on a common pipeline is often used. The purpose of the work is to substantiate the need to check the strength of the discharge drainage pipelines of water-abundant mines during hydraulic shocks, which can occur during sudden unauthorized shutdowns of pumps, regardless of the height of the water lift. In the work, a graphical-analytical method was used to study the flow of a hydraulic shock in the main drainage system of a mine, the height of the water rise in which is 269 m. The result of the study is that, based on the equipment that is used, it has been established that the required flow of the installation can be provided with parallel operation of two pumps, however, without cavitation, they will be able to work at a suction height less than 2.7 m. At the same time, with the simultaneous operation of three pumps on a common pipeline, their permissible geometric suction height exceeds 5.0 m, which ensures high reli-ability of the installation. With the specified pumping scheme, the flow rate in the discharge pipeline increases to 5.36 m / s, which can cause an unacceptable increase in head in the event of a sudden shutdown of the pumps. It was found that despite the appearance of a shock increase in the head in the installation only in the third phase of the hydraulic shock, its value is 96 m, i.e. the head in the installation in case of a sudden shutdown of the pumps increases by 27% compared to the operating head. Practical value of work results consists in justifying the fact that the determination of the need to protect the drainage system from the negative effect of water hammer cannot be done based only on the height of the water supply.