2. What function do the three highlighted sub-systems perform?
3. Describe the operation of the circuit.
4. If the double acting cylinder has a diameter of 30mm and a rod diameter of 5mm; and the supplied air pressure is 5N/mm, calculate:
a) The outstroke force
b) The instroke force
I will leave the answers as a comment so you can have a chance to answer the above questions before seeing them.
1.
ReplyDelete1&2: 3/2 plunger, spring return valve
3: Shuttle valve
4&5: Push Button Spring Return valve
6&9: Unidirectional Flow Control Restrictor
7: Reservoir
8: 5/2 pilot pilot valve
10: Double Acting Cylinder
2.
Blue: OR control
Green: AND control
Orange: Time Delay
3.
*Valve 1 and 2 are connected to a shuttle valve which creates OR control.
*If the plunger on either valve 1 or 2 is pressed the valves will be actuated and main air will flow from port 1 to 2 and this will provide a signal to actuate valve 8.
*This signal is delayed using the Unidirectional FCR and the reservoir. Air is restricted and slowly fills up the reservoir. When it is full the air pressure will be sufficient to actuate valve 8.
*When valve 8 is actuated to its 1/4 state main air will flow from port 1 to port 4 and instroke the cylinder.
*Valve 4 and 5 are connected in line to create AND control.
*When the push button on both valves are pressed they will both be actuated and main air will flow port 1 to port 2 of valve 4 and then port 1 to port 2 of valve 5 and this will give a signal to valve 8.
*Valve 8 will be actuated to its 1/2 state and main air will flow from port 1 to port 2 and outstroke the cylinder.
*The unidirecional FCR (9) restricts the exhaust air as the cylinder outstrokes, ensuring that it moves slowly.
4. Force = Pressure x Area
The area on the outstroke is found using the diameter:
(note that I can't add symbols or smaller text here)
A = Pi r2
= 3.14 x (15)2
= 706.5mm
F = P x A
= 5 x 706.5
= 3530N
The area on the instroke needs to exclude the area of the piston rod. So . . .
A = Pi x R2 - Pi x r2
= 3.14 x (15)2 - 3.14 x (2.5)2
= 706.5 - 19.6
= 687mm
P = F x A
= 5 x 687
= 3435N