water ring vacuum pump of factors affecting the energy consumption
Water-ring vacuum pump is the most commonly used equipment in paper machine vacuum system. Compared with other vacuum equipment, especially the more popular turbine vacuum pump, water-ring vacuum pump has a simple structure and lower cost. It can provide a large range of vacuum capacity and work normally in a more rigorous environment.
Therefore, under the existing technical conditions, water ring vacuum pump still occupies a dominant position in the paper industry. But the water ring vacuum pump also has the disadvantage of low efficiency and high energy consumption. Enterprises sometimes have to increase the speed of pumps in order to obtain larger pumping capacity, but the result is that the energy consumption of pumps increases and the cost of use increases. The process of gas compression in water-ring vacuum pump is approximately isothermal, so the compression power of water-ring vacuum pump is generally calculated according to the formula of isothermal compression. The maximum consumption power of water ring vacuum pump is shaft power. The shaft power of water-ring vacuum pump is mainly composed of three parts: the power consumed by liquid, the power of compressed gas and the power consumed by overcoming the friction between packing box and bearing. The exhaust pressure of water-ring vacuum pump is basically constant and the suction capacity is basically stable.
Therefore, it is considered that the isothermal compression power is only related to the suction pressure. In order to reduce the power consumption of water ring vacuum pump and improve its efficiency, it is necessary to reduce the useless power to the greatest extent. Water ring vacuum pump can form a stable working water ring. When the design parameters of the water ring vacuum pump and the inlet and outlet pressure are determined, only when the impeller speed reaches a certain range can the kinetic energy of the water ring match the pressure potential energy of the pump inlet, the gas compression of the water ring vacuum pump can be completed according to the operating conditions.
There are different design pressures for different water-ring vacuum pumps, so different impeller speeds are needed to ensure the normal operation of water-ring vacuum pumps. However, if the speed is too high, the linear velocity at the top of the impeller blade will increase, which will lead to greater shear force between the impeller section, shell and water ring, thus causing more energy loss. Therefore, when adjusting the speed of water-ring vacuum pump, the balance between pump efficiency and energy consumption should be considered comprehensively so as to give full play to the role of water-ring vacuum pump. Excessive water temperature will also reduce the efficiency of pump suction. Therefore, it is necessary to keep the working water at a lower temperature, which is one of the reasons why the working fluid should be continuously replenished.