Hydraulic systems consist of several mechanical components. Because these components are mechanical, they require a certain amount of time—known as response time—to react to different pressures, flows, signals, etc. This schematic shows a simple hydraulic system that extends and retracts a cylinder by using a closed center directional control valve. This system also uses a relief valve that allows the pressurized fluid to return to the tank, when pressure rises due to the valve being closed. As shown in this result, an improperly sized accumulator will result in a pressure surge due to the time between the directional control valve closing and the relief valve opening. In this example, HyPneu software is used to determine the proper sizing required for an accumulator to avoid this pressure surge.
During the production of sheet metal, large slabs of steel run across rollers applying constant force in order to create a uniform thickness throughout the slab. The slab runs the rollers until the desired thickness is reached. If roller between two slabs constantly applies the same amount of force between the two slabs, ripples will be produced in the metal the entire way down the production line. Using HyPneu, the proper logic controls can be used to create less force through the roller when it is not on a slab, and reapply the correct amount of force when it is in contact with another slab. Our example shows the controls establishing the proper control to reduce the ripples in the sheet metal.
Production times can be cut drastically when manufacturing certain parts by feeding the part at a rapid rate and then slowing the feed rate at a specific point to have more accurate positioning. In order to accomplish this task, a regenerative system may be used. HyPneu can simulate this system using several cartridge valves as shown, as well as using PLC to control a one-directional control valve. Using either method provides the same result in HyPneu, which shows that the extension speed slows down after reaching four inches and then retracts quickly after extending five and 1/2 inches.