When developing a hydraulic system, selecting the proper valves is critical. But it’s only one small step in a much larger process. To help us gain some insight into best practices for valve selection and overall hydraulic system design, we spoke with Deltrol Corp. Director of Sales, Rick Guidish. The following is a Q&A edited for length and clarity.
Fluid Power World: When selecting components for a hydraulic system, what are the key specifications used to select valves?
Rick Guidish: There are many. The first key thing would be fluid power operating parameters, and by that, we’re talking about max operating pressures, flows. You want to have a good understanding of the temperature that the system will be applied into, both from an ambient temperature and also an oil temperature standpoint. Oil temperature helps deride the proper seal selection when you’re designing valves and manifolds. Leakage requirements, what the flow media is, and, in general, the overall operating parameters. You also want to take into account, key electrical parameters as well, is there a desired current limitation, for example, a duty cycle of the system, is the operation continuous or intermittent duty? That’s important information in order to size and specify correctly.
Additionally, we always want to size the components with pressure drop in mind. We’ll get into more a little bit later. That’s one of the key advantages of hydraulic integrated circuit manifolds. What this does is drives an overall more efficient system that results in lower horsepower consumption and lower current draw. Especially in mobile applications, lower current draw leads to longer battery life, which can result in overall lower system cost. On the other side of that, from a pressure drop standpoint, there’s always a trade-off too. It’s easy to go ahead and simply put in larger valves to reduce pressure drop to make it more efficient, but those larger components are going to be more costly. You’ve got to weigh the benefits of that lower pressure drop and the cost associated with that, relative to the gains that you have my doing so. The other thing you want to be aware of is any overall size limitations. A big advantage of the circuit manifolds itself is reduced size. But when you’re designing it, it’s important to know if there are limitations within which you need to design the manifold.
Another thing we want to look into is making sure that we have a sound understanding of the application and how it’s being used. We need to evaluate the overall potential risk associated with the operation so that we can take proper design measures to offset that. Lastly, one thing you want to look at when you’re going into a project is what is the customer’s objective. Sometimes they know exactly what they want, you design it, you prototype it, you go straight to production… Other times, it starts as a concept, you have an idea, and you’re brainstorming, and you want to simply prove that functionality of an overall hydraulic system.
FPW: What are the benefits of integrated hydraulic circuit manifold, and what additional specifications need to be considered when specifying, beyond just the valve functions that you just mentioned?
RG: There are many advantages. The two I would put at the top of the list are more energy efficient, and less overall system cost. Customers, especially in the mobile market, are always looking for great efficiency, and as we all know, everybody’s looking for lower overall cost. That’s a big driver in making decisions on mobile equipment. From an energy efficiency standpoint, the key with integrative circuit manifolds is primarily just lower pressure drop. This results in fewer hose runs, typically much more efficient connections in terms of the flow paths that are drilled into the manifold, and you end up with fewer bends and turns in the flow paths. It’s simply a more efficient and compact system.
It’s also a smaller overall size and weight. This may not be as critical in industrial applications, because you typically have larger areas, larger machines where space isn’t as critical, or weight. But when you’re talking mobile applications, every inch of space is valuable and, believe it or not, every ounce of weight reduction can make the difference between success and failure. One thing that we at Deltrol Fluid Products do, is we developed what we call a zero profile product. This helps make integrative circuit manifolds more efficient, in the sense that we’ve developed valves that actually fit down below the other valves and make more efficient use of the aluminum block that you’ve already paid for. In other words, you’ve got valves that populate the outside service of the block, you have flow paths going inside the block.
Often times, you’ve got material in there that remains and isn’t used. This zero profile product allows us to put pressure control functions, flow control functions, and check valve functions into this valve and bury them underneath the valves that are on the surface of the manifold. This configuration helps keep that integrative circuit manifold more efficient, and smaller. Circuit manifolds definitely have a cleaner appearance. That’s since you’re eliminating all of the hoses that would otherwise connect the valves in the system. All these hoses now consist of internal drill paths into the manifold.
You’ll often hear people refer to a loose valve component system with many hoses as a plate of spaghetti. Integrative circuit manifolds virtually eliminate that because all of that is drilled through the manifold. You could also anodize the aluminum block just about any color you want. This also helps create a much cleaner appearance, and can often be used also to create a level of brand awareness associated with your machine.
Sticking to overall system cost, much of that is also associated with less assembly and installation time, because you don’t have all of those connections between all of those valves. When we develop an integrative circuit manifold, we populate it. We do full functional 100% testing, and the customer simply has to take this block, mount it, make the external hose connections, and you’re up and running. Fewer leak points, obviously, is another advantage of the circuit manifolds, due to the fewer pipe connections into hoses. This results in a much more environmentally friendly system. This becomes even more important in mobile applications where oil landing directly in the ground is not environmentally friendly. That sums up just a few of the advantages. But, really, they’re endless.