Control valves for waterjet systems and related devices, systems, and methods

A method for operating a waterjet system, comprising:

• pressurizing a fluid to a pressure within a range from 20,000 psi to 120,000 psi at a pressurizing device;
• conveying the fluid within a first portion of a fluid conveyance of a waterjet system, the first portion of the fluid conveyance defining a first flowpath extending from the pressurizing device to a control valve of the waterjet system and containing a first volume of the fluid at a first pressure at a given time;
• conveying the fluid within a second portion of the fluid conveyance, the second portion of the fluid conveyance defining a second flowpath extending from the control valve to a jet outlet of the waterjet system and containing a second volume of the fluid at the given time, the second flowpath being shorter than the first flowpath;
• operating the control valve via an actuator to selectively throttle the fluid and thereby controllably reduce a second pressure of the second volume of the fluid relative to the first pressure;
• directing fluid from the first volume of the fluid through a relief valve operably connected to the fluid conveyance upstream from the control valve;
• directing a jet including fluid from the second volume of the fluid toward a workpiece to erode a portion of the workpiece, the second pressure corresponding to a velocity of the jet;
• and
• automatically operating the relief valve in concert with the control valve to automatically vary a flow rate of the directed fluid through the relief valve.