Float-type fiber Bragg grating sensor for measuring the density of molten metal

The quality and behavior of the molten metal can be defined by density,which is reflected the basic changes of the inter-atomic distance and coordination number of molten metal.A float-type fiber Bragg grating sensor is manufactured to measure the density of molten metal.The floater submerged in molten metal is controlled by buoyancy force. Through the driving rod,equal armed lever and connecting rod,pulling the equal strength cantilever beam,the deflection is changed.On the basis of detecting the wavelength shift of fiber Bragg grating which is pasted on the surface of cantilever beam the buoyancy values be obtained.The density of molten metal is detected.The theoretical sensitivity of the sensor is 0.115pm/(kg/m3).According to the four times experiment,the average density value of the molten metal is 7.574 ×103 kg/m3,which is less than the theoretical data for 7.621×103 kg/m3.The relative error is 0.62,the root mean square error is 117.371kg/m3.