Capacitance-based polymer melt density measurement device and method

The invention discloses a device and a method for measuring the density of a polymer melt based on capacitance, and relates to the technical field of online measurement of physical property parameters of the polymer melt. Comprising a transmission machine, a feeding cylinder and an electric appliance controller, the transmission machine comprises a servo motor, a speed reducer and a lead screw elevator, the servo motor drives the lead screw elevator to achieve lifting motion, the lead screw elevator drives a plunger rod to extrude melt in the feeding cylinder, and a spoke type pressure sensor is installed on the plunger rod; a temperature sensor and a capacitance sensor are installed on the feeding cylinder, the plunger rod can be controlled to move through electric appliance control, and temperature and pressure measurement and display of the melt and displacement measurement and display of the plunger rod are achieved. According to the invention, the melt state under different temperatures and pressures in