Centrifugal Pumps

These essentially comprise the single impellor pump commonly referred to as 'centrifugal' and multi-impellor pumps referred to as 'turbine'. The centrifugal single impellor pump may be either the 'single for 'double' entry type, that is, water may enter from one or both sides of the impellor. The latter would be considered only for large flow rates and indeed the simpler design, construction and maintenance of the single entry centrifugal pump generally leads to its adoption. These single stage pumps can develop heads of 15 m at reasonable efficiency but if one is prepared to sacrifice the efficiency they can easily accommodate twice that load. For example, for a clear water pumping duty of 10 l /s (120 gpm) and 36 m (120 feet) head the single impellor radial flow pump might require twice the power taken by a three-throw ram pump; although it would produce a much neater, simpler and cheaper installation. For small delivery rates a reduced gap at the impellor outlet is desirable. However, for manufacturers and operational reasons, the outlet aperture cannot be unduly reduced. To help reduce the risk of blockage especially a t the impellor outlet the suction range inlet must be protected by a s t r a i n e r of suitable screen size which must not reduce the t o t a l i n l e t area. Indeed such a s t r a i n e r would normally provide for 3 to 5 times the suction range i n l e t area. Since such pumps are nQt self-priming a non-return valve is also required a t the foot of the suction range and it is normal practice to combine the foot valve and strainer as an integral unit.

centrifugal ETA-N seri 65x65-160

source : IMWA.info

Related Posts:

0 komentar: