Research On Application Of HVD In Pumps Load

After discussed several methods that are used in large fans and pumps for speed regulation and energy saving, the thesis puts forward a new method that can be used in pumps for efficient and energy saving speed regulation in relation to HVD.HVD variable speed clutch is an application of the technology of hydroviscous drive. It bases its driving mechanism on the law of Newton internal friction. The method of calculation by which pumps use HVD for energy saving is analyzed by virtue of the characteristic curve of pumps. The author carries out analysis and calculation for the towing torque that comes out from the operating mode. A new method aiming at reducing the towing torque is raised as well. After analyzed four types of running conditions of the friction disk during the process of speed regulation, the author comes up with a new method of calculation so as to determine the number of friction disk and the size of the external and internal diameter as well. The dynamic mathematics model is created directing toward the liquid friction section of HVD system. A great deal of heat is generated during the speed regulation of HVD, so appropriate coolant system must be designed in order to make sure that the system would run normally. As a result, it is of great importance to analyze the source of heat. The thesis discusses it in four aspects. When the pilot oil pressure of the forcing piston is regulated, the oil film thickness between the friction disks is changed, thus we achieve the goal of HVD speed regulation. There are many ways to regulate the oil pressure and two of them, electrohydraulic proportional flooding valve control and HSV pulse width modulation are discussed in this thesis. At the end of the thesis, a brief introduction of the electrical control system of HVD and a method of using PID control to carry out speed of rotation of closed loop control are brought forward.