Question: A company is manufacturing bladders for truck brakes. The bladders are formed from pieces of fabric-reinforced rubber by placing the pieces of rubber on a form and closing a press. Heat and pressure mold the rubber into the correct shape. The ram has a 30-in. bore and 20-in. stroke. Oil is stored in a reservoir over the press. This oil flows down and fills the ram as it is closed by the side cylinders. When the ram closes, a sequence valve opens to apply high pressure to the ram and develop the required force. The press must close in 30 s. This requirement establishes the flow from the reservoir into the cap end of the ram. Sufficient negative pressure (suction) must be generated to produce the required flow across the pilot operated check valves. The characteristic curve for the pilot-operated check valve (?P vs. Q) is given in Fig. Total force to close the platen is 2400 lbf . If the supply pressure is 2000 psi, what size cylinders are required for the side cylinders?
