Industry new

Troubleshooting Challenge: Proportion - Valves are inconsistent

A simple circuit was designed to relieve large castings from the conveyor belt on the floor to the elevator to another conveyor belt located in the high building. A three-position proportional directional valve used in the elevator, a filter, and a relief valve to secure a pressure-compensating pump. The limit switch is used at each end of the elevator card's stroke signal proportional valve deceleration until the elevator stops. The elevator has a hard stop at a lower delivery position and relies on a proportional valve and a limit switch for the stop position on the conveyor. A hard stop at the top will result in the casting moving out position and the side frame conveyor.
The amplifier has four separate ramp adjustments so that acceleration and deceleration can be adjusted independently of each other in both directions. The average weight casting is used to set the speed of the ramp and the final lifting speed.
The proportional valve used was ordered with an EVDT option with electronically pneumatically regulated spool position feedback to ensure accurate spool position. During the installation and commissioning process, the project engineer found that if castings with different weights were used, the stopping point of the lifting cylinder in the upper position would be different, causing paper jams. The heavier castings cause the elevator to suddenly stop at the desired position and lighter the stopping point required for the elevator to overshoot.
Engineers can adjust the deceleration ramp to solve this problem so that production may recover, but as a lighter or heavier casting needs to be lifted, as soon as possible, make the necessary adjustments.
If the proportional pneumatic ball valve spool will go to the same open position with 1⁄2% accuracy, why the stop point changes up to 2 due to the LVDT option. When the casting weight changes?

PREVIOUS：Electric actuator application analysisNEXT：Traditional valve parts various skills and so