Manifolds offer a variety of benefits when included in a simple or complex assembly. Whether simple or complex, manifold assemblies offer a centralized location for connecting multiple valves within a system.
The two main types of manifolds include a single-piece design, and modular block design. A single-piece design is meant to support all necessary valves within a system and is made up of all passages within the system, in one piece. A modular-block design, on the other hand, typically supports just one valve, its internal passages, and flow-through provisions. In a modular block design, there will usually be several modular blocks which are connected to each other, and which make up the entire system.
Custom hydraulic system manifolds are also referred to as Hydraulic Integrated Circuits (HICs). They combine and optimize multiple machine control functions with the use of multi-function cartridge valves. The maintenance to change out or upgrade the cartridge valve is minimal, thus reducing downtime and cost.
Custom Hydraulic Manifold
The hydraulic integrated circuit shown demonstrates how different types and sizes of valves can be assembled into a manifold for multifunctional operation (photo courtesy of EHA, Inc.)
See EHA Custom Manifolds Brochure
The key to designing the most effective custom hydraulic manifold is to fully understand the WHY – Why do you need the manifold? And WHAT – What is your problem in need of solving or the opportunity in need of pursuing? More specific, What motion control functions do you want the manifold to perform on a machine or system? EHA engineers collaborate with customers to design the most relevant manifolds for their machine or system.
As part of the IFP Group of Companies combined, IFP/EHA is both distributor and manufacturer/integrator. This allows us to select from a broad range of manifold product components and accessories from a long list of fluid power brands.
EHA Assembler working on a custom manifold order
Hydraulic Manifold Purpose
A hydraulic manifold distributes hydraulic oil throughout a circuit and can regulate the fluid flow between pumps, actuators and other components. A manifold can also be used to split a primary source of fluid off into secondary circuits, or conversely, be used to join exhausted fluids. A manifold can also be used as a plumbing standard for which to attach valves. In some cases, a manifold can be used to replace fluid connections in an entire circuit. The benefits of a well-designed manifold may include:
- Enhanced performance and greater compatibility
- Reduced maintenance time & cost
- Improved facility and machine appearance
- Improved energy efficiency and reduced energy costs
- Support constrained space environments
- Greater design freedom through component diversity
- Minimize the chance of oil leaks by reducing the number of hoses and connections
- Help reduce pressure drop and heat fluctuations/heat stress
For more insight on hydraulic manifolds reference article “What are hydraulic manifolds” :by Paul Heney appearing in publication, Mobile Hydraulic Tips. Also article: “Tips and trends in manifold circuits” by Yudi Raina featured in Hydraulics and Pneumatics magazine (Manifolds & HICs.)
Among the many benefits of a made-to-order block is the ability to achieve a smaller size through a more intelligent design. This provides major benefits for design engineers. Manifolds can be attached directly to machine components, i.e. pumps, cylinders, accumulators, reservoirs etc. to shorten the hydraulic flow path and boost performance.
EHA custom HPU unit featuring attached custom manifolds
The primary concern in fluid power circuits is to either control the rate of flow or the pressure level. One misconception has been that pressure may be controlled with an orifice or flow control device. This is never accomplished with any degree of accuracy. For accurate control of force, six types of pressure controls have been developed.
- Relief valve
- Unloading valve
- Sequence valve
- Reducing valve
- Counterbalance valve
- Brake valve.
By symbol, these valves closely resemble one another. Often only their location in the hydraulic circuit will designate what type of pressure valve they are.
Pressure Sequence Valve
A sequence valve is a normally closed pressure control valve that ensures that one operation will occur before another, based on pressure. In our clamp and drill system we want the clamp cylinder to extend completely before the drill cylinder extends. To accomplish this, we place a sequence valve just before the drill cylinder. We set the cylinder to 500 psi. This will ensure that the drill will not extend before we have reached 500 psi on the clamp cylinder.
Flow conditions (pump, accumulator and return)
It is important to keep in mind how adding more manifolds to the system will affect pump performance and whether or not it will cause overheating and pressure drop. Also, a consideration whether accumulators can. Help to modulate the system if needed.
Machine/component duty cycle
Duty cycle is the proportion of time during of time during which a component, device, or system is operated. The duty cycle can be expressed as a ratio or a percentage. The more the use the sooner it will wear out. Overall life cycle savings are realized through optimization of the overall system with properly selected manifold components integrated for maximum efficiencies with the longevity of components in mind. This will help justify the cost of custom manifold designs.
Flow rates, pressures, and manifold length may be limiting factors with some modular manifold systems. For example, one system may be limited to 20 gpm at 3,000 psi, and the manifold package cannot be more than 3 ft long. Another is restricted to 35 gpm and 3000 psi. A third accommodates fluids at pressures to 6,000 psi and has no length limit. These restrictions can be designed around but be sure the system you specify can adequately handle your needs.
Fluid power is another method of transferring energy. This energy transfer is from a prime mover, or input power source, to an actuator or output device. This means of energy transfer, although not always the most efficient, but where properly applied, may provide optimum work control. Energy may be defined as the ability to do work.
Valves are mechanical devices that controls the flow and pressure within a system or process. They are essential components of a piping system that conveys liquids, gases, vapors, slurries etc.
Different types of valves are available: check, pilot, pressure control/sequence, pressure reducing, unloading, counterbalance, pressure relief etc. Each of these types has a number of models, each with different features and functional capabilities:
- Stopping and starting flow
- Reduce or increase a flow
- Controlling the direction of flow
- Regulating a flow or process pressure
- Relieve a pipe system of a certain pressure
Multi-valve 4 station valve stack example:
Pilot valve (1)
- Size 6 directional control valve
- Float center
- Shifts size 25 directional control valve
Flow control valve (2)
- Size 6 sandwiched configured
- Controls shift speed of size 25 directional control valve
Directional control valve (3)
- Size 25
- Starts, stops, and changes direction of flow to hydraulic cylinder
Check valve (4)
- Pilot operated
- Locks cylinder in position
Pilot valve (5)
- Size 6 directional control
- Pilot opens check valve
Pressure reducing valve (6)
- Size 16, three-way reducing valve
- Reduces pressure to piston side of hydraulic cylinder
Pilot valve (7)
- Size 6 pressure reducing valve
- Pilot control for size 16 pressure reducing valve
Manifold metal types
Aluminum and ductile iron are the most common metals used in manifolds. Both have been relatively inexpensive and readily available. Due to metal-market pricing, it may influence the cost of the project. Since ductile iron is quite heavy, it is used less in mobile manifold applications because of the extra weight.
Aluminum manifolds are more adaptable. They can be used in both pneumatic and medium pressure hydraulic applications. However, mobile-manifold applications have been trending with higher psi due to design and manufacture innovations.
Aluminum Flat Bar is available in various alloys offering a range of weldability, corrosion resistance and machinability. High strength aluminums can be used in many manifold designs. High corrosion-resistance aluminum alloys are commonly used in marine applications. Sometime stainless steel is used for special conditions, like saltwater or acid medium.
When designing HICs, it’s best to use specialized circuit design software. Some manufacturers provide access to specialized manifold design software with facilitated design capabilities. For example, Integrators with access to Sun Hydraulics’ QuickDesign online integrated package allows designers the opportunity to expeditiously create and order custom design manifold components.
Also, access to 3D CAD software such as PRO-E and SolidWorks is beneficial and helps reduce the chance for errors. In addition, programming advancements in CNC machining for manifolds has helped drive down costs and increased the availability and delivery of manifolds.
Choosing a partner with product sourcing, integration, and manufacturing capabilities is beneficial. It will make the process of specifying, designing, and building custom manifolds less daunting.
EHA is a full-service fluid power systems and controls manufacturer and service provider located in Cedar Rapids, Iowa. As part of the IFP Group of Companies, we offer engineering, fabrication & sub assembly, field service and repair, system start-up, and programming.
We have the capability of satisfying all of your fluid power needs, from standard to custom power units, manifolds, and cylinders to automation solutions, and more. For example:
Consider Atos Explosion Proof valves – Learn More
Electro-Hydraulic Automation (EHA)
Service Areas: United States
Ph: (319) 395-0050
TF: (800) 342-1699
1620 Blairs Ferry Road N.E.
Cedar Rapids, IA 52402