What is Hydraulic Manifold?
A hydraulic manifold is a hydraulic network specifically designed to manage the flow fluid between hydraulic components. The components include hydraulic pumps, hydraulic cylinder, hydraulic actuators, and hydraulic valves.
It can be interchangeably referred as hydraulic valve block and it is responsible for an organized and regulated fluid flow pressure.
It is typical in any hydraulic fluid system where predetermined fluid speed and force is important for desired output. Some of the areas include; heavy construction machinery, food processing equipment, marine equipment, etc.
Parts of Hydraulic Manifolds
Manifold body is metallic and it accommodates the different valves, hoses and channels for fluid passage.
Are fluid entry or exit points in the manifold and are well labelled. The fluid is channeled into or out of the manifold via hydraulic lines or hoses.
Seals are crucial in fluid leakage prevention and ensuring fluid pressure is maintained within hydraulic system.
The mounting surfaces provide secure attachments points needed for the different hydraulic valves that are mounted on a manifold.
Are holes on the manifold that allow secure installation of a manifold to a hydraulic system, equipment, machinery, etc.
Are found within the manifold and are responsible for controlling efficient flow direction between the ports. They are designed in a way that reduces chances of fluid pressure drop
Factors to Consider when Choosing Hydraulic Manifold Type
Several elements need to be put into consideration when selecting manifold type.
· Fluid Type
This is important as it determines pressure maintenance technique and also affects the interaction with manifold material. Remember, hydraulic systems can handle a wide range of hydraulic fluid.
· Operating Pressure
Diverse manifolds produce and maintain varying pressure levels for different hydraulic fluids.
· Type of Material and Finish
Material choice and finish influence the design and composition of valve to be used in a particular hydraulic manifold.
· Environmental Elements and Condition
The environment of operation of a manifold matter in terms of operating temperature and heat conditions.
· Seal Type
Material composition in a joint sealing of manifold are also essential when settling for a manifold.
· Duty Cycle
The length of service of a hydraulic manifold must be evaluated when selecting a type.
· Number and Type of Valves
Different manifolds permit different number of valve connections, i.e. 2 or 3 or 5-valve assemblies.
· Port Size, Type and Location
Various manifolds offer different port size and location for flow rate control.
· Mounting Location
Some manifold mount on the side, some from the bottom and some at the center.
· Flow Conditions
Your application type determines flow rate thus influencing your choice of manifold.
· Electrical Connections and Voltage
Various electrical configurations exist for different manifolds and so do voltage requirement. Application need helps determine type of manifold to choose.
Types of Hydraulic Manifold
There are diverse types of hydraulic manifold and each of them provide unique hydraulic service.
In this section we will look at each type of manifold, its key features, benefits, application, etc.
Single Piece Manifold Block/Mono Block Hydraulic Manifold
Single piece manifold is designed to accommodate all valves and fluid pathway for an entire hydraulic system and comes in two designs.
· Laminar Designs
This is a type of mono block that is made by stacking together steel metal plates with fluid passage between them. The stacked metal plates are then combined into a single unit by joining together solid metal pieces using a filler metal. This process is known as brazing.
The flow channels can be created anywhere in laminar manifolds. The shape of the channels is however dictated by the required flow pressure.
Laminar manifold is known to tolerate high pressure of about 98,000 psi and offer parallel fluid flow without the risk of mixing. They are common in analytical laboratory applications such as chromatography, spectrometry, etc.
The fluid pathway cannot be modified due to brazing hence making the design rigid and made for custom applications only.
· Drilled Metal Block
Drilled metal block is a manifold made from drilling circuit and fluid passageways through aluminum, steel or ductile iron block. This type of manifold has valve pathways drilled straight anywhere on the block to allow valve placement.
Some drilled blocks have cartridges valves within the manifold and connect the fluid channels via cartridge valves. In others the cartridge valves have threaded parts that support them via threaded cavities. For some, the cartridge valves are slipped into the manifold and supported by the metal plates.
Modular Manifold Block
Modular manifold block is an individual block with one or two valve and internal interconnecting pathways for the valves. Usually, modular manifold consists of an assembly of similar blocks to form a complete unit.
They are flexible and can be manipulated or joined to other modular blocks.
They are made of steel or aluminum or cast iron and designed for a specific need or general design. Modular manifolds blocks consist of end plates on their ends to allow for extra connections to pumps or tanks.
Spacers between blocks allow size modification to be able to hold over-sized valves. Interconnecting plates blocks and redirect fluid flow from one pathway to the next between blocks. Plugging of divider plates either block or facilitate fluid movement.
The upper part of a modular manifold is drilled and fitted with ports to hold sub-plate-mounted valves. Blocks with several identifiable ports can be found in modular system for different sub-plate mounted valves and cartridge valves.
Modular manifolds are either bench assembled horizontally or stacked.
2-Valve Manifold
This is used to control pressure flow of fluid or gas from two different pressure sources. It can be found in refrigerators or plumbing connections to help measure and regulate flow rate at the same time.
3-Vavle Hydraulic Manifold
This type of manifold can block or equalize two pressure gauges in a control system. The three valves can function as follows:
Isolation valve: This helps separate pressure gauge without process interference during maintenance.
Equalizer valve: helps equalize pressure in the system thus averting instrument damage during pressure removal.
Calibration valve: assists in removing excess pressure in a system during calibration process.
5 Valve Manifold Blocks
Works in a similar way as a 3-valve manifold block but has additional valves; another isolation valve and a vent valve.
The vent valve is only for removal of excessive pressure from the system. The rest of the valves; two isolation valves, calibration valve and equalizer vales provide similar services as in 3-valve manifold.
Direct Connect or Inline Hydraulic Manifold Block
Direct connect manifold is a 2-valve assembly and a 1/2 inch NPT line connection type of manifold.
Its attachment is either a male or female process connection with the female connection design being popular.
Coplanar Hydraulic Manifold Block
Coplanar manifold mounts from the bottom from the bottom part and does not need process mounting holes. It comes in 2, or 3 or 5-valve assemblies, and ½ inch or ¼ inch process connection.
In some coplanar manifolds, 5-valve manifold assembly has gas meters.
Traditional Manifold Block
Contrary to coplanar manifold, traditional manifold has its connection on the side and with 2 or 3 valve assemblies. It may or may not need process mounting holes and the process connection sizes are either ½ inch or ¼ inch.
Conventional Hydraulic Manifold Block
This type of manifold allows you to mount on the side to traditional flanges and not directly to pressure transmitter. It can be found with a 2, or 3 or 5-valve assemblies and a center-to-center connection of 2 1/8-inch connection.
Parallel Circuit Manifold Block
This is a type of manifold that permits the flow of hydraulic fluid in several parallel channels without mixing it. This helps reduce pressure drop in a hydraulic network.
Series Circuit Manifold Block
Unlike in parallel manifold block, series circuit manifold allows flow of fluid in a synchronized fashion from a central point. The fluid channels are interconnected allowing the fluid to flow sequentially from one path to the next.
Common Cavity Manifold Block
This special manifold block permits multiple fluid flow to several hydraulic components from a central hub. It is advantageous because it is possible to have and regulate various hydraulic channels from a single point.