Figure 1: Pneumatic solenoid valves on a single-piece design manifold
Pneumatic manifolds enable installation of multiple pneumatic solenoid valves in a centralized location where a single air supply and exhaust port is shared among all valves. The compact design of manifolds lowers the costs of valve installation by eliminating a large portion of tubing in the system, which results in minimal system complexity, quicker dismantling, less leakage and overall less maintenance costs. The shorter path flows resulted from using manifolds reduces pressure drops and overall system energy consumption. Pneumatic manifolds are used for applications that require numerous valves, such as, mobile machinery and heavy industrial equipment.
Manifolds come in different pressure ratings, number of stations, port sizes, flow rates, functions and housing materials. Some manifolds can also be brand specific, meaning they can only be used with that specific brand’s valves. Other manifolds adhere to standardized mounting patterns, like ISO 5599 and ISO 15407. This allows the manifolds to be used with valves manufactured by others.
Pneumatic manifolds fall into two general categories: single-piece design and modular block design. The single piece design can accommodate a specific number of valves with pre-determined port geometries. On the other hand, a modular block design is more customizable and consists of single blocks that usually support one valve and the assembly of a series of similar blocks provide the manifold.
Figure 2: Single-Piece Manifold
Most common, is a drilled metal-block made out of steel, aluminum, or cast iron to create the required flow paths and ports. Figure 2 shows an example of a single-piece manifold design. Since they are single-piece designs, they have minimal leakage paths making them a robust solution even for high pressure applications. However, due to them being drilled, they do have design limitations as the flow path must be straight. Typically, you can mount between 2-10 pneumatic solenoid valves on a single-piece manifold. They need to be specified for how many ports (for example, for a 3/2-way or 5/2-way valve) and how many valves. Blanking plates are available to close off ports.
Single-piece manifolds can also be body ported or manifold ported. A body ported manifold, as seen in Figure 2) has the valve outlets on top of the valve. For a manifold ported manifold, the valve outlet is on the bottom so the manifold has another media route through the side of the manifold.
Mondular block manifolds are designed as their name suggests, to be modular, and can be seen in Figure 3. As each manifold holds one valve, you can add or subtract additional blocks for easy modification, maintenance, and mixture of different valve sizes. They consist of basic building blocks as well as interconnecting, divider and spacer plates. These plates are usually installed in-between basic modules and each serve their own function. The interconnecting plates can divert the flow from one passage to the other between the basic modules. Divider plates have the ability to block a flow passage by plugging it, and spacer plates simply adjust the dimensions between basic modules when a larger sized valve is used and additional space is required. As they are modular, additional leakage paths are available but all blocks and plates are equipped with o-rings and seals to prevent leakage.
Figure 3: A disassembled modular manifold design
Figure 4: Blanking Plate
If a manifold has more ports than solenoid valves, a blanking plate is required to close of any unused ports. The blanking plate, as seen in Figure 4, ensures that the air does not leak out through the unused ports and are easily secured into place. They are either brand specific or adhere to ISO 5599 or ISO 15407 standards.
Manifolds that allow interchangeability of valves from various manufacturers are designed according to ISO standardized interfaces. These standards specify dimensions of valve ports and mounting interfaces as well as required electrical connections.
ISO 5599 specifies the requirements for the mounting interface surface for five port pneumatic directional control valves, for use at a maximum rated pressure of 1.6 MPa (16 bar). It gives dimensions and tolerances of the interface features, port identification, and identification of the result of control-mechanism actuation.
Figure 5: An example of an ISO 5599 manifold
Within the ISO 5599 standard there are sizes 1, 2, 3, and 4 so often times the valves and manifolds are labeled ISO 5599-1 (or 2/3/4). These numbers correspond to the size of the valve (1 being the smallest), therefore, the manifold must match the corresponding ISO number to properly mount the valve.
Figure 6: ISO 5599 sizes for ISO 1, 2, 3, and 4
ISO 15407 specifies dimensions and tolerances of the interface features, port identification, identification of the result of control-mechanism actuation, dimensions, tolerances and specifications for the mounting interface and electrical connector for five-port pneumatic directional control valves, sizes 18 mm and 26 mm, for use at a maximum rated pressure of 1.6 MPa (16 bar).
Figure 7: An example of an ISO 15407 manifold
Within the ISO 15407 standard there are sizes 01 and 02, so often times the valves and manifolds are labeled ISO 15407-01 (or 02). These numbers correspond to the size of the valve (02 being the smallest), therefore, the manifold must match the corresponding 01 or 02 to properly mount the valve.
Figure 8: ISO 15407 sizes for ISO 02 and 01
If a manifold is deemed to make the application simpler and easier, then they are easy to select. The main selection criteria are:
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