Welcome to the World of Hydraulic Manifolds Unless you’ve been involved wit h hydraulic systems for some time, it’s quite unlikely that you’ll be highly familiar with the ins and outs of the hydraulic manifold. Its purpose is to regulate the flow of fluid as it passes between actuators, pumps and other components in a hydraulic system. Some engineers might compare the manifold to the switchboard of an electrical circuit as the flow of fluid is under the control of the operator. For example a hydraulic manifold of a backhoe loader will control whether the fluid is being diverted to the telescopic arms of the back bucket or the front bucket. The levers used by the operator in their cabin are connected to the manifold and it’s these that are used to control what the backhoe does. How does a manifold work? A manifold works with a number of valves connected to each other. It is through the combinations of these valves that enable the manifold to control complex behaviour. The hydraulic valves are what control the flow of pressurized hydraulic fluid and direct it either to a cylinder or a hydraulic motor. Manifolds are also known for many advantages including space reduction, pressure reduction, less connections and therefore less leaks. They also make it faster to assemble a hydraulic system as the components are consolidated into one unit. Some engineers feel wary of troubleshooting systems that have manifolds as there may not be an obvious place to start looking for issues. However, as long as the design of the hydraulic system includes test points, finding the root of problems can be much faster and easier. If transducers are attached, in the event of issues the data can then be displayed. Typical Hydraulic applications The applications where you’re most likely to find manifolds in use are in production equipment, material handling, heavy construction, food processing, oil field, off-highway equipment and machine tools. There are two basic variations of the manifold… One is of the modular-block design which will support valves by providing interconnecting passages for just one or two valves with possibly some provision for flow-throughs. The other type is a mono-block design. This will support an entire system with valves and passages. The material that manifolds are made from need to be strong and solid to handle the high pressure of the fluid. This is why they are manufactured in either laminar or drilled metal block. Most laminar manifolds will be created in steel with either milling or machining techniques used to pass through the layers of metal. Through the use of several layers that make up the passages, the manifolds are strong enough to take up to 10,000 psi. Made in a bespoke custom manner, laminar manifolds are designed to suit the hydraulic system with passages added where needed. When it comes to drilled metal block manifolds they can be manufactured from a number of different materials including steel, ductile iron and even aluminium. Blocks are drilled until there are flow passages, circuit paths and valves added where required. In some cases there could be cartridge valves added to cavities in the surface of the manifold. Sometimes these are kept in place by plates and other times they are held in place by threaded bodies. Manifold selection considerations When it comes to selecting a hydraulic manifold to suit your hydraulic system setup there a number of different questions that you’ll need to answer. Keep in mind that there are software packages on the market that can be used to help the engineer design his or her perfect solution. 1. What type of fluid will you be expecting the manifold to handle? 2. Consider your seal materials – they will need to be able to connect the manifold to pipes and other components. 3. Which material and finish is going to suit your needs the most? 4. There are certain environmental conditions for every setup – keep these in mind including temperatures for your choice. 5. What pressure will the manifold be under when it’s under normal working conditions and maximum strain? 6. Check that the ports are suitable in size, location and type. 7. Are there enough valves on your manifold? 8. What flow conditions will there be – ie from a pump, an accumulator or a return? 9. What electrical voltage do you need and how will this be connected? 10. How will the manifold be mounted to the system? This information should fill in any gaps in your knowledge about hydraulic manifolds. If you have any questions, feel free to drop us a line, we’ll do our best to help.