Hydraulic manifolds are increasingly gaining traction and replacing plumbing networks in new builds. Engineers and equipment builders typically give reasons for this trend because manifolds significantly reduce a circuit’s footprint, maintenance costs, and design complexity. However, as implementation goes into effect, there have been noticeable improvements in fluid power performance, such as: less leaks, less air invasion, smaller pressure drops across components, and higher flow rate. Below, we will discuss each of these advantages in further detail.
Reducing a Circuit’s Footprint
Pipe networks require specific distances between components based on the pipe size to allow tools to access tight spaces between components and to provide enough length for bends, fittings, adapters, etc. The only variables influencing the distance between components on a manifold are the size of each component and the actuator apparatus (handle, cylinder, remotely piloted solenoid valve fittings, etc.). Reducing a circuit’s footprint effectively reduces transportation costs and broadens the locational possibilities for the end user.
Reduce Complexity and Long-term Costs
In a piping circuit, there are various fittings that must be used to connect components. The price for schedule 160 elbows, nipples, etc. gets quite excessive and the bill of materials grows beyond the page of your drawing. If tubing is used instead of pipe, then a skilled tube bender is still required to fit each component. This usually is a process that requires all parts on hand to ensure proper fitment. If scaling a business is in mind for systemizing the assembly of a product control system, then an alternate method should be approached. It is no secret that manifolds are a fair upfront investment. However, you eliminate multiple fittings, pipes, tubes, etc. and your assembly and installation time will decrease to a fraction compared to conventional piping networks. Your bill of materials is now fewer line items and creating a routine product is easier than ever. The turnover of skilled shop workers and replacing expensive equipment is less of a concern because all that is needed is an impact wrench and a few other sized wrenches to assemble components to a manifold.
Reducing Labor Time for Maintenance
Removing a valve in need of maintenance from a piping network requires a fairly significant time investment. Unless there are unions between each valve, multiple pipe fittings and other components must be removed to access the subject valve. This usually is a very awkward position that requires a big wrench to fit into a small space. Then, get the wire brush ready to replace all the Teflon tape. With a manifold, just remove the four bolts that secure the valve to the block. All SV’s have two small screws that retain the body and housing, so you won’t need to worry about parts falling on the floor upon removal.
Increase Flow Rate and Decrease Pressure Drop
Bends, transitions between fittings, component orifices, etc. are all forms of flow constrictions that are inherent to conventional piping networks. These constrictions lead to a greater pressure drop and thus a lower flow rate. If the goal is to close a blow out preventer in a short interval of time, a designer must consider all the fittings in between the directional control valves and pressure regulators. Valves and regulators have estimated Cv and flow rate values that will be limited by piping up and downstream. Each fitting or bend is added friction loss that will only decrease the flow rate. Hydraulic integral manifolds obsolete all fittings in between valves, while orifices between the valve port and manifold are matched and bends are reduced. This is the truest way of obtaining a theoretical and desired flow rate. We have even heard testimonials from customers saying that the flow rate was too high! In this scenario, the equipment builder could have sized down and saved a lot of money.
Reduce Air Entry
Air is a hydraulic power unit’s biggest and most unpredictable enemy. The primary cause for air entering a hydraulic circuit is through a pump’s inlet, which can lead to gradual failure due to cavitation. However, small amounts of air also can enter through joints and fittings in pressurized plumbing. When fluid flows from one fitting to the next there is a change in diameter that results in a venturi effect. Pressure decreases instantaneously at the constriction, where fluid velocity surges, then the pressure increases immediately after. This constriction can create a spike in negative pressure. High pressure fittings are designed to seal off positive pressure, but not negative pressure. So, at these points of negative pressure, atmospheric air can theoretically be drawn into the system. The increased aeration reduces the lubricity of the hydraulic fluid and ultimately degrades the fluid further. The degraded fluid loses lubricity (excessive thinning of the oil) and leads to component failure that requires a boundary layer of lubrication to operate. If the components survive this, the fluid will then overheat and damage any seals that are not rated for operation at the elevated temperature. Integral control valve manifolds are seamless, where the only location for air entry is at the supply and outlet lines, which is a lot easier to detect than a pipe network with dozens of entry points.
Reduce Leaks
Every connection point is as susceptible to fluid leaks as it is to air entry. These two issues obviously go hand in hand. The only way to reduce leaks is by reducing connection points, and thus replacing all fittings, nipples, etc. with a manifold.
Summary
Manifolds are expensive. There’s no doubt about it. However, in the long run, they are proven to save on installation, transportation, and maintenance costs all the while leveraging the scalability that comes with having a repeatable and reliable product. If you’re ready for the next step towards the future of circuit design, then please reach out to PacSeal today and we will help create a custom valve manifold assembly.
