Power consumption and energy saving of the hottest

Editor's note: energy saving is to eliminate waste, such as turning off the light when going out. This paper expounds the power consumption of hydraulic power injection molding machine and how to save energy, and clarifies the misunderstanding of motor power and how much energy can be saved

motor power consumption

the injection molding machine is driven by the motor, and the oil pump generates pressure and flow to drive the pump and oil pump motor. The motor converts electrical energy into rotating mechanical energy. The commonly used motor is a three-phase squirrel cage design. The speed is determined by the number of poles and AC frequency, and the torque is determined by the load. A large load increases the current and torque. This kind of motor can be overloaded twice temporarily. At no-load, the current is very low, and only enough torque is needed to overcome the friction of the bearing

oil pump

the oil pump converts the rotating mechanical energy into pressure and flow

the pressure comes from the resistance on the oil circuit. The greater the resistance, the greater the pressure, and the greater the pressure is provided by the greater torque

injection cycle

a single oil pump should meet the needs of multiple action output during the injection cycle. The advantages and speed of our company's testing machine equipment depend on the well-designed pump and oil horse. 2. The conversion of melting temperature up to will change the pressure and flow into output and speed

the output, speed, torque, speed and power consumption of the injection cycle are roughly divided into four levels, as shown in the table below. The energy saving of variable displacement pump and frequency converter is that it does not need to provide just enough flow at full speed. In the injection molding machine before the proportional valve was widely used, the pressure and flow were manually adjusted. The motor is constant speed and the oil pump is quantitative

during the pressure maintaining action, the screw speed is almost zero, and almost all the oil pump flow flows back to the oil tank under the pressure maintaining pressure, causing waste. The wasted power consumption not only heats up the pressure oil, but also consumes energy to cool it with cold water

Daming's TM series relay controlled injection molding machine adopts three levels of pressure (high, medium and low), which is composed of three overflow valves. The oil pump is quantitative, and the throttle valve is used to control the speed/speed. Excess flow returns to the tank

proportional pressure valve

with the help of numerical control technology, the proportional pressure valve can greatly increase the number of stages of pressure, such as 100 (%) or 140 (kg/cm2). By replacing multiple overflow valves with one valve, the pressure control can be arbitrary, which can reduce the investment cost. The me series injection molding machine launched by Daming in the mid-1980s adopts this technology

proportional flow valve

the proportional flow valve shared by the proportional pressure valve also replaces multiple throttle valves with one valve. Since the oil pump is still quantitative, it does not play an energy-saving role

large and small pumps

the design of large and small pumps provides three optional flows, namely, small pump flow Q1, large pump flow Q2 and large and small pump flow q1+ Q2. The best distribution is q2=2 * Q1, so that the three-stage flow is divided into three equal parts

when the flow needs to be% only turn on the small pump

when the flow needs to be% only turn on the large pump

when the flow needs to be%, both the large and small pumps start

only turn on the small pump when maintaining the pressure, and the energy consumption is reduced by 2/3 compared with a certain amount of pump. Due to the limited flow of variable displacement pumps (<220 l/min), large and small pumps are generally used on large machines, such as Daming's me650 injection molding machine

variable displacement pump

variable displacement pump will significantly increase the number of stages of flow, such as 100 (%). Therefore, in the process of studying and exploring new materials, new processes, new techniques and new structures, it is only necessary to set the flow rate to 1% when maintaining pressure, and the energy consumption is reduced by 99% compared with a single certain amount of pump. The working principle of variable displacement pump is to change the displacement. Inclined plate piston pump is the most common, but there are also eccentric vane pump designs. The displacement can be changed by changing the angle (0o-45o) or the amount of eccentricity of the inclined plate. When the displacement changes, the flow will change accordingly. Daming's me IV series uses variable displacement pumps. (to be continued)