Innovative motion control solutions since 1947

Two Kinds of Hydraulic Manifolds, Part II: Modular Manifolds

In Part I, we discussed the benefits of one of the two major types of hydraulic manifolds — the ‘single-piece’ manfolds, laminar and drilled-block. Today, we’re going to talk about the other major kind of manifold: the ‘modular’ manifold.

Modular manifolds have a single massive advantage over single-piece manifolds: they can be changed on the fly as the job evolves. Sometimes called the ‘erector set approach,’ modular manifolds involves a few to scores of iron, steel, or aluminum blocks, each of which has a single valve or other operator inside. Modular manifold systems can be assembled horizontally or stacked.

Most often, plates are installed between the basic ‘building block’ components to make for regular spacing and to allow for small variations in the location and size of intake and outflow passages.

The method by which the manifold blocks are connected varies by builder. Some use rods that extend through the length of the manifold and are secured on either end with nuts. Others have flanges on every block so they can be bolted together one at a time. Still others have sockets and threaded heads alongside the hydraulic passages inside each block that snap together. No matter how the blocks are connected, every block has an O-ring around every passage entering or exiting it that abuts the O-ring on the adjacent block for the purpose of forming a seal.

Most such blocks also have the necessary electrical connections built into the blocks, connecting the machinery to the appropriate solenoid. Some instead utilize channels that allow for runs of standard electric cable instead.

The limitations of modular manifolds are more dramatic than those of single-block manifolds. Internal pressure, flow rate, and the length of an individual manifold are all much more sensitive in a modular manifold than they are in a single-piece manifold.

Hydraulic manifolds are amazing tools, able to replace as much as 300 lbs of tubing and valves in as little as a single cubic foot of space. Compared to the tubing and valve setup, a manifold can cost two-thirds to half as much to assemble and install, save a mountain of space, and require only a single hydraulic filter to keep the fluid running smoothly. Whether you choose drilled-block, laminar, or modular manifolds, you’re certain to appreciate the advantages.

Two Kinds of Hydraulic Manifolds, Part I: Single-Piece

Hydraulic manifolds come in two basic types: the single-piece design that contains all of the valves and passages needed in a single metal chunk, and the modular design where each block contains exactly one valve and the various passages needed for that one valve to work. Each has their own advantages; in this article, we’ll discuss the benefits of choosing a single-piece hydraulic manifold.

Single Piece Manifolds come in two basic kinds: ‘lamniar’ and ‘drilled-block.’

Laminar Type Manifolds are composed of multiple layers of metal with holes drilled in them such that when the layers are brazed together, they form the necessary passages. As each layer is formed, the necessary mechanics of each valve are put in place. There is no limit to the number of valves — or the size of valves — that can be mounted in a laminar type manifold.

Laminar manifolds can withstand pressures of up to ten thousand psi, and can be custom-designed for any task. Because of the brazed construction and permanently shaped passages, however, it cannot be modified if changes become necessary; it must be replaced entirely. Laminar manifolds are generally more expensive than drilled-block manifolds as well.

Drilled-Block Manifolds are similarly custom-made for specific applications, and also cannot be altered after creation. Most often made from a single slab of iron, steel, or aluminum, a number of straight passages are drilled to create the flow passages and to provide the space necessary to insert the valves and other moving parts. Some such manifolds use threaded passages to screw the machinery into place; others lock the parts into place using plates attached to the manifold’s surface.

Drilled-block manifolds, being single metal pieces, can with stand more pressure than the valves within them are able to — meaning they’re effectively unbreakable, as in almost any case, a hydraulic valve will give out and the fluid will be ejected before the manifold itself cracks. They’re also the least expensive kind of manifold to produce, in general.

Single-piece manifolds in general have the advantages of withstanding greater pressures and being less expensive than modular manifolds. To learn the advantages of modular manifolds, come back next time for Part II.