Patent ID: 8555706

Claim:
A falling speed measuring sensor for a falling body viscometer which is utilized in the falling body viscometer for causing a falling body to fall into a measured substance accommodated in a tubular measuring container, measuring a falling speed of the falling body by means of the falling speed measuring sensor, and measuring a viscosity of the measured substance by using the falling speed, the falling speed measuring sensor comprising: a first coil pair disposed on an outer periphery of the measuring container, separated from each other in a vertical direction, electrically connected in parallel, and provided to have different polarities from each other; and a second coil pair disposed on the outer periphery of the measuring container, separated from each other in the vertical direction, electrically connected in parallel, provided to have different polarities from each other, and arranged below the first coil pair by a specified distance, wherein the falling speed measuring sensor is configured to determine: a first time between a time that a maximum value is taken and a time that a minimum value is taken in an electric potential generated continuously over both coils of the first coil pair in a passage of the falling body through the first coil pair at which there is defined a coincident electric potential with a reference voltage generated over the first coil pair by an electric potential applied from a power supply to the first coil pair; a second time between a time that a maximum value is taken and a time that a minimum value is taken in an electric potential generated continuously over both coils of the second coil pair in a passage of the falling body through the second coil pair at which there is defined a coincident electric potential with a reference voltage generated over the second coil pair by an electric potential applied from the power supply to the second coil pair; and an elapsed time from the first time to the second time, wherein the elapsed time is a passing time taken for the falling body to pass through the specified distance.