pnuematics
...e at fully open state. 3) When push button on 3/2 way control valve is pushed the piston rod extended. The piston retracted at a very fast rate. 4) After adjusting the variable throttle relief valve (tighten the adjusting screw) the piston rod extended at a slower rate compared to the first time when the exhaust is left fully open state. The piston still retracted at a very fast rate; same as the 1st try when the exhaust valve is at a fully open state. 5) The whole extend motion is slowed down by just tightening the adjusting screw but the retract motion is not affected at all. 6) The adjusting screw is now fully tightened. 7) When the push button is “ON”, the piston did not move but when continue to leave the push button at on state, the piston will extend at an extremely slow rate. 8) The piston will not fully extend and will come to a stop after the piston had traveled about one tenth of the total extended length. 9) Theoretically the piston should not move at all when the variable throttle relief valve is fully closed but due to leakage and the age of the equipment used the piston managed to move by just a short length. Observation for circuit 2 1) The observation is same as the observation for Circuit 1. Comparison between Circuit 1 and Circuit 2 Similarities 1) Both of the circuit will have the same piston motion characteristics. 2) Adjusting the relief valve only controls the extending speed of the piston. Differences 1) The location of the variable throttle relief valve for Circuit 1 is connected at the Pe2 side while for Circuit 2 the variable throttle relief valve is connect to the Pe1 side. 2) The directions of the variable throttle relief valve on both circuits are different. 3) For Circuit 1 the exhaust port of the variable throttle relief valve is connected to the port on the end of the cylinder (position X). 4) For Circuit 2 the exhaust port of the variable throttle relief valve is connected to the port B on the 5/2 way control valve. Discussion 1) Through our finding, the variable throttle relief valve is a unidirectional control valve. Therefore the direction of the exhaust valve will change the characteristics of both the circuit when it is connected in reverse to the given position in both circuits. 2) For Circuit 1, the arrow on the variable throttle relief valve is pointing in the direction of the air entering the cylinder; therefore this kind of circuit is called supply air throttling or Meter-in speed control where the air entering the cylinder is being controlled. 3) For Circuit 2, the arrow on the variable throttle relief valve is pointing outwards from the cylinder. This kind of circuit is called exhaust air throttling or Meter-out speed control because the exhaust air traveling out of the cylinder is being controlled. Internal construction of a variable throttle relief valve. Further Discussion Since the variable throttle relief valve is a unidirectional valve. We tired to connect both Circuit 1 and Circuit 2 again but with the position of the variable throttle relief valve reverse. Results Circuit 1 - When the 3/2 control valve is pushed to supply air into the circuit the piston rod extended at a very fast rate (uncontrolled speed) - When the adjustable screw on the variable throttle relief valve is adjusted and the push button is push the extension of the piston...