The literal definition of manifold is “many and various” and you’ll probably have come across it in terms of pipework. It describes a system that branches out from one into several openings – or, like a car’s exhaust system, it collects several branches into one pipe. In pneumatic systems, a manifold is a device for distributing compressed air or gas from a single source to multiple outlet paths. It functions as a control centre that directs the airflow to the various pneumatic components attached to it. These could be actuators, solenoid valves, control valves or other compressed air devices.
What Do Manifolds Do?
The pneumatic manifold’s main purpose is to control and manage compressed airflow efficiently within a pneumatic system. They consolidate multiple airflow routes into one centralised solution, making systems more compact and better organised. Pneumatic manifolds simplify the distribution of air and help regulate the pressure, direction and timing of the airflow. This allows pneumatic components to operate precisely and in a coordinated manner in all areas of industrial automation.
Pneumatic manifolds are available in all sorts of configurations, so you can match them to your specific needs. You can select manifolds using a variety of criteria, such as port sizes, pressure ratings, flow rates, station counts and housing materials. Some pneumatic manifolds are designed for use with a manufacturer’s own-brand valves, while others are designed in compliance with universal standards such as ISO 15407 and ISO 5599. These specify the dimensions of pneumatic fluid power components such as valve ports, together with the necessary electrical connections and mounting interfaces. Choosing a manifold by standards compliance offers you the maximum amount of flexibility to cherry-pick your components from different manufacturers.
Types Of Pneumatic Manifold
Pneumatic manifolds are manufactured in two categories: single piece or modular block. A single piece manifold is designed for a specific number of valves with pre-configured port geometries. Modular block pneumatic manifolds consist of a collection of individual blocks that each support just one valve. The modular construction means that they’re much easier to customise by connecting additional blocks.
Single Piece Manifolds
Single piece manifolds take the compressed air from a single inlet and channel it into multiple outputs like cylinders, drives, valves, etc. Using its integral ports, the manifold distributes the air evenly to each connected device, enabling the pneumatic system to coordinate all its operations.
The most common design for a single piece manifold is a drilled block, creating holes for the various ports and flow paths. They’re robustly made of cast iron, aluminium, steel or plastic and can handle most high-pressure applications. A single piece pneumatic manifold can manage from two to 10 pneumatic solenoid valves, with unused ports being closed off with blanking plates. When selecting a manifold block of this type, you need to specify how many ports (for example, for a 3/2-way or 5/2-way valve) and how many valves you need.
Modular block manifolds are much more adaptable, combining single blocks – each holding one valve. You can add or remove blocks if you need to modify or maintain the manifold. The one downside to modular blocks is that they present additional leakage paths, so you have to seal each connection point with an o-ring to reduce leakage. As well as these basic building blocks, modular manifolds may also have plates installed between individual blocks for interconnecting, spacing, dividing or blocking, as follows:
Interconnecting plates are used to divert airflow
Spacer plates are used to accommodate larger valves, adjusting the space between blocks
Divider plates can be used to block a flow path
Blanking plates close off any unused ports when the block has more ports than valves
Selection Criteria For Pneumatic Manifolds
The number of valve ports must match the number of ports on the manifold. If you don’t know the number of valve stations, or may change them in the future, you’re best off with a modular design. When you have a fixed number of valves, a better solution is to choose a single piece manifold with a pre-determined number of valve stations.
The type of material you choose for your pneumatic manifolds is typically governed by the following criteria:
Pressure requirements: aluminium and stainless steel can withstand higher pressures than plastic.
Application environment: for corrosive or high-temperature environments, stainless steel is best for its resistant qualities. Aluminium is prone to corrosion, but it’s good at dissipating heat and is suitable for general-purpose applications. Plastic is corrosion-resistant, but not good in environments with high pressure or temperature.
Durability: the most durable material is stainless steel, followed by aluminium. Plastic is less durable but much lighter, if that’s a contributing factor.
Maintenance: stainless steel and aluminium offer longer life spans and easier maintenance than plastic.
Cost: metal manifolds are generally more expensive than plastic ones.
Mounting: choose either brand-specific mounting or one that’s correctly sized and compliant with the appropriate ISO standard.
ISO standards: ISO standards 5599 and 15407 specify the dimensions and tolerances required for pneumatic fluid power mounting interface surfaces, as related to five-port directional control valves. It includes specifications for the mounting interface and electrical connector (if used), port identification, interface features, maximum rated pressure, etc.
Pneumatic manifold blocks are of the utmost importance in applications where numerous valves are required, such as heavy industrial equipment and mobile machinery. Manifolds can cater to a variety of specific needs, according to selection criteria such as different flow rates, port sizes, pressure ratings and housing materials. You can also choose manifolds with standardised mounting patterns or brand-specific products.
By choosing this system, you can make a single air supply and exhaust port serve multiple pneumatic solenoid valves. This makes the system significantly less complex, less prone to leakage, and cheaper to maintain. The shorter flow paths in pneumatic manifolds consume less system energy, and this underscores their overall efficiency.