Figure 10-34 depicts a custom manifold that can eliminate many plumbing connections and make valve replacement easy. Such manifolds are usually more expensive than simple plumbing, but can save many times the extra first cost by minimizing fluid loss through leakage and the cost of cleanup.
A number of companies specialize in designing and building custom manifolds. All they require is a schematic of the circuit with the valves to be included inside chain lines; plus other information such as preferred pipe connection type, connection locations and size, which face or faces to leave clear and manifold material. If there is a preferred mounting arrangement, it should be noted along with mounting bolt locations.
Remember: manifolds are difficult to modify, so they should only be applied to proven working circuits. If in doubt about the viability of a new design, work out the bugs in standard piping before buying a manifold.
Most check valve functions are available as modular or sandwich valves that mount between the directional control valve and subplate. Figure 10-35 shows most of the common configurations presently offered by fluid power suppliers. These modules are usually available in all valve port sizes up to D08 (3/4 in.).