Method for twin screw positive displacement pump protection

A method to protect a twin screw positive displacement pump, the method comprising:

• receiving, by a signal processor, a signal, wherein the signal includes information about power, an actual torque, a current speed, an actual viscosity and an actual specific gravity related to the operation of the twin screw positive displacement pump;
• determining, by the signal processor, an actual corrected torque, wherein the actual corrected torque is based on the actual torque at the current speed, the actual specific gravity of a fluid being pumped, the actual viscosity of the fluid being pumped, a rated viscosity of the fluid being pumped, and a rated specific gravity of a fluid being pumped, wherein the rated viscosity and rated specific gravity are determined when the twin screw pump is operated to rated conditions;
• determining, by the signal processor, a tuned corrected torque at a specific operating speed, wherein the tuned corrected torque is based on an interpolated tuned value torque at the current pump speed, the rated specific gravity, the actual specific gravity, the rated viscosity, and the actual viscosity;
• determining, by the signal processor, an actual corrected tune ratio based on a ratio of the actual corrected torque divided by the a tuned corrected torque;
• and
• compensating, by the signal processor, the torque measurements for a change in a value of a specific gravity and a change in a value for a viscosity of a fluid in the system due to a change in a temperature of the system;
• and
• determining, by the signal processor, to enter a pump protection mode for the twin screw positive displacement pump when the actual corrected tune ratio is less than or equal to a tuned ratio set point.