Measuring abrasive flow rates in a conduit

An abrasive material delivery system for use with a liquid jet cutting system, the abrasive material delivery system comprising:

• a valve configured to adjust or stop an inflow of abrasive material into the abrasive material delivery system from a source of abrasive material;
• a chamber downstream of the valve and configured to receive the inflow of abrasive material from the valve;
• a metering component configured to control an outflow of abrasive from the chamber to a cutting head of the liquid jet cutting system;
• a sensor configured to monitor movement of a top surface of a portion of abrasive material within the chamber as the top surface moves through the chamber, wherein the sensor is configured to detect the top surface of the portion of abrasive material at a first location in the chamber and at a second location in the chamber downstream of the first location;
• and
• a processing device operably connected to the sensor and configured to determine an abrasive flow rate through the metering component based on a speed of the top surface as monitored by the sensor.