To answer these questions must consider the characteristics of pump units in a group of parallel connected pumps. Work the pump unit in the group is fundamentally different from the conditions of a single unit. Maximum supply a single unit due to the minimal hydraulic resistance pipeline and the correct choice of pump shift it to the high values of the innings is impossible. Therefore, the operating point at the same time is a boundary that prevents the displacement unit in a zone of possible occurrence of cavitation and overload the pump rotor drive.
When working in a group of any change in status of any unit, through its inclusion in the closed (shutdown) or regulating the speed of the impeller changes the state of the system. In this case, a redistribution of load between the units, which can lead to an increase in supply of one group of units with the risk of getting into the zone of cavitation and overload and Little Giant pump Little Giant pumps Little Giant submersible pumps drive the other group with the risk of hitting them in the region of instability and surging.
For this purpose, we developed a mathematical model of the pumping unit with adjustable drive and is composed of a special computer program, allowing to scan characteristics of practical interest range of loads. At the same time as the initial data about the pump is its pressure and cavitation characteristics, as well as the characteristic efficiency. As background information in the program also introduced the following parameters: power of the Taco drive, the difference between the elevations of water level in receiving tank and the axis of the impeller, the dependence of head loss in the suction line of the pump from its filing, the maximum and minimum allowable values of the frequency of rotation (K = nm / nh, where nm - the current speed of the impeller, nh - nominal), the minimum acceptable efficiency values.
Grundfos Grundfos 15-42
As an example, Figure 1 shows the construction of possible modes of operation of pump unit D-1250-65 with adjustable drive. Seen from the figure that the range of possible restrictions is a curvilinear polygon Grundfos 15-42 F Taco 007 Taco 007 IFC Taco 007 pump Taco pump Taco Pumps water pump well pump well pumps wet rotor pump Wilo pumps, each side presents limitations on certain parameters: surge, cavitation, the maximum permissible speed of rotation of the impeller, the permissible power Taco pump rotor pump. Right border restrictions VSPD obtained for the Taco power ustavnolennoy Ndb = 350 kW and suction Hbc = 0. Raising the water level in receiving tank (or decline marks the axis of the pump) at 3 meters of water. Art. and installation of Taco pump rotor Ndb = 450 kW will significantly extend the range of possible modes of operation of the pump Grundfos 15-58 Grundfos circulating pump Grundfos pump Grundfos pumps Little Giant little giant 5-apcp little giant 5-msp Little Giant 5asp-ll little giant 6-cia Little Giant 360 Little Giant 360S Little Giant UPSP-5 Little Giant Utility Pumps plumbing pump pumps sewage pumps Submersible pumps.
Range of possible modes of operation of the pump Taco Taco 0013 Taco 006 with adjustable drive within the constraints
