Manifolds are used in my many fluid power applications, depending upon the application. Manifolds are used in hydraulics as well as pneumatics, and can be used to mount valves or to consolidate plumbing. When used for mounting valves, they are the interface between the valves and the ports to be plumbed into.
With industrial style hydraulic valves, such as ISO valves mounted on D03 or D05 patterns, for example, the valves terminated with plain ports surrounded by O-rings, and cannot be plumbed directly into a hydraulic system. The manifold is a block, or series of adjoining blocks, which has an interface for the valve(s) to mount to, ports for the fluid to travel, and then ports to plumb the manifold to the rest of the circuit. The pressure passage can be parallel to the valve pressure ports, or in series, joining the tank to pressure port of subsequent valves.
Pneumatic valves use various manifold mounted systems, which can be ISO standards or manufacturer specific. Just as with hydraulic valves, one long block, or various small adjoining blocks, have directional valves mounted to the manifold(s). The manifold will have common pressure ports feeding the DCV’s, and return ports are combined into the manifold and usually exhausted to air.
The advantage of manifold mounted valve systems is in their modularity; standard valves of various, easily exchangeable iterations can be mounted to a manifold to customize the circuit and its number of actuators. As well, a standard valve series can be mounted to manifolds employing any type of port, such as NPT, Metric or ORB, rather than producing every valve with every version of port, saving manufacturing and inventory costs.
Manifolds can be used outside of valving, as well. A manifold can simply be a chamber with two or more ports joined in series to reduce plumbing. For example, a return line manifold with six smaller ports joining to one large tank port will save the need for a series of expensive tee’d together fittings, reducing both cost and the chance of leakage. A manifold can be used less commonly in pressure lines as well, cleaning up plumbing and improving appearance as well.