Original sentence: This pump consists of two ball valves: a stationary valve called the "standing valve" and a valve on the piston connected to the bottom of the sucker rods that travels up and down as the pump reciprocates, known as the "traveling valve"
Edited sentence: This pump consists of two ball check valves: a stationary valve called the "standing valve" and a valve on the piston connected to the bottom of the sucker rods that travels up and down as the pump reciprocates, known as the "traveling valve"