Fracturing pump systems having a hydraulically-driven assembly applying variable amounts of pressure on packing

A system for pumping abrasive slurry, comprising:

• a fluid end having a cylinder and a piston movable to pressurize an abrasive slurry in the cylinder;
• the cylinder having at least one cylinder sidewall;
• packing located to prevent the abrasive slurry from leaking between the piston and the at least one cylinder sidewall;
• and
• a hydraulically-driven assembly configured to apply variable amounts of pressure on the packing;
• wherein the hydraulically-driven assembly comprises:
• (i) a hydraulic supply containing hydraulic fluid;
• (ii) a hydraulic assembly for interacting with the packing, the hydraulic assembly comprising:
• a hydraulic assembly piston for imparting pressure on the packing, the hydraulic assembly piston being movable toward and away from the packing;
• and
• a passage from the hydraulic supply to the hydraulic assembly piston;
• and
• (iii) a control system for adjusting a position of the hydraulic assembly piston and thereby adjusting pressure on the packing, the control system comprising:
• non-transitory computer memory;
• a processor in data communication with the computer memory;
• a sensor in data communication with the processor;
• a pump in data communication with the processor and in fluid communication with the hydraulic supply;
• a valve in data communication with the processor for selectively allowing the hydraulic assembly piston to move away from the packing;
• and
• programming stored in the computer memory that, when executed by the processor, causes the processor to:
• (a) utilize data from the sensor to determine a desired amount of hydraulic control pressure to be applied to the hydraulic assembly piston;
• and (b) actuate at least one of the pump and the valve to apply and regulate the desired amount of hydraulic control pressure to the hydraulic assembly piston using the hydraulic fluid in the hydraulic supply.

A method for automatically adjusting pressure applied to packing within a fracturing pump system, comprising:

• providing a fracturing pump system comprising:
• a fluid end having a cylinder and a piston movable to pressurize fluid in the cylinder, the cylinder having at least one cylinder sidewall;
• packing located at the cylinder sidewall to prevent fluid from leaking between the piston and the at least one cylinder sidewall;
• and
• a hydraulically-driven assembly configured to apply variable amounts of pressure on the packing, the hydraulically-driven assembly comprising:
• a hydraulic assembly piston for imparting hydraulic control pressure on the packing, the hydraulic assembly piston being movable toward and away from the packing;
• and
• a passage from the hydraulic supply to the hydraulic assembly piston;
• providing a control system comprising a processor in data communication with:
• a sensor;
• a pump in fluid communication with the hydraulic supply;
• and
• a valve for selectively allowing the hydraulic assembly piston to move away from the packing;
• activating the sensor to determine a first attribute of the fracturing pump system;
• determining, via the processor, a first hydraulic control pressure based on the first attribute of the fracturing pump system;
• actuating at least one of the pump and the valve to apply and regulate the hydraulic control pressure based on the first hydraulic control pressure;
• activating the sensor to determine a second attribute of the fracturing pump system;
• determining, via the processor, a second hydraulic control pressure based on the second attribute of the fracturing pump system;
• and
• actuating at least one of the pump and the valve to apply and regulate the hydraulic control pressure based on the second hydraulic control pressure.