The Ultimate Buyer's Guide for Purchasing Multi Stage Hydraulic Cylinder

Hydraulic systems for lifting, lowering, or pulling can vary according to each individual project. There are many different configurations possible, so choosing the right components for your system should be done carefully to ensure a safe and successful outcome.

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Important! For the inexperienced, understanding pressurized hydraulic systems can be complex. Every heavy-lift project has its own unique requirements and using the wrong set-up could be catastrophic. Please consult a suitably qualified and experienced person before you start work.

What follows is a simple introductory overview of how to configure a lifting system for anyone unfamiliar, or unaware of the options available. We've put together eight examples to get you started, ranging from simple hand pump cylinder sets to complex synchronous lifting systems.

If you need advice on choosing the right hydraulic cylinder please see our Buyer's Guide.

Basic Single-Acting Set-Up for Hydraulic Cylinders for General Applications

This diagram shows a very simple hydraulic system suitable for a single-acting lifting application. Arrangements like this can be used in a wide variety of general-purpose maintenance situations, or in a hydraulic press.

It shows a manual hand pump for controlling the cylinder advance. (Note that this could be substituted for a powered pump). It's worth knowing that a cylinder with a capacity of 25 ton and above may require many hand-pump strokes ' especially for longer stroke applications.

• For convenience, a set-up such as this can often be purchased as a kit. These contain everything you need, including a case for storage and protection of the items.
• You may also want to consider maintenance kits and useful cylinder accessories, such as baseplates for additional stability or tilt saddles to prevent plunger damage. These additional items offers more versatility and can help prolong cylinder life.
• Even in a simple setup such as this, using a pressure gauge is always recommended, as it gives a window into the hydraulic system. The Enerpac GA45GC 45® gauge assembly is perfect when using a hydraulic hand pump.

Single-Acting Cylinder Set-Up with Longer Stroke

This shows another basic hydraulic system using a single-acting hydraulic cylinder. This time it includes a cylinder with a longer stroke and an air-powered hydraulic pump.

Note the use of a JBI-Series Cylinder Baseplate which increases both stability and load distribution.

When using any of our powered pumps (air/electric) we always recommend using our glycerine-filled gauges to reduce needle vibration for accurate pressure reading.

Double-Acting Cylinder Set-Up for a Powered Retract of Heavy Loads

When lowering a heavy load it is sometimes important to have controlled retract. When this is a requirement, a system designed for a double-acting cylinder should be used. A double-acting cylinder uses hydraulics to lift or lower the load, unlike single-acting cylinders which rely on a return spring and gravity to retract the plunger. The latter can be time-consuming. (especially on longer stroke cylinders).

• Using a pilot-operated check valve (v66) installed in the inlet port of the cylinder for temporary load holding.
• As before, when using a powered pump, use a glycerine-filled gauge to minimize needle vibration.
• The above diagram shows a powered pump, but a hand pump may be used, however, please ensure the pump reservoir is sufficient to both fully advance and retract the cylinder(s).
• Note that a pump with a 4-Way Directional Control Valve is needed.
• Install flow control valves in both advance/retract lines for greater control/fine-tuning.

Safety Tip ' Ensure all couplers are connected and working properly ' a defective or incorrectly attached coupler may block the flow, resulting in potential pressure intensification which would result in excess pressure flowing out the external pressure relief valve on cylinder.

2 Double-Acting Cylinder Set-Up for Push or Pull Applications

The system above is for applications requiring 2 lift points where a controlled lift is needed. Manifold blocks are used to split both flow directions to the 2 cylinders, with the advance line utilizing flow control valves to enable fine-tuning of the synchronicity of lifting across multiple points. Note that the pressure gauge goes into the advance line.

• The flow valves are added to the manifolds for a controlled extension.
• Whenever you intend to use multiple cylinders ' make sure the pump has a large enough reservoir to contain enough hydraulic fluid for the stroke of all the cylinders.
• Where a controlled retraction is required you could install flow control valves into the retract line manifold.
• A pump with a 4-Way Directional Control Valve is needed.
• For convenience, you could utilize the Enerpac AM42GC/AM41GC control manifold gauge assemblies, which incorporates the manifold, control valves, gauges, and couplers for up to 4 jacking locations.

2 Cylinder Set-Up Using Single-Acting Cylinders

The above shows another two-point lifting set-up, but this time it is simplified by using single-acting cylinders. A safety holding valve is used with each cylinder for temporary load holding.

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Further reading:
The Ultimate Buyer's Guide for Purchasing Electric Wheelloader
What is Semi Automatic Strapping Machine and Why Do We Use Them?

For long-term load holding applications, consider Enerpac hydraulic lock nut cylinders which mechanically lock off the load ensuring safe working in and around the area.

Safety Tip ' Never work under a hydraulically suspended load. Always mechanically lock the load either by using cribbing blocks or mechanically operated locknut cylinders.

Multi-Point Hydraulic System Using 4 Single-Acting Cylinders

The above shows a common multi-point hydraulic system using single-acting cylinders and control manifolds.

• It's recommended to install gauges on each outlet port of the control manifold, as this will show the load distribution across the four jacking points. This assists with load control and helps increase synchronicity.
• JBI-Series base plates are used to help increase stability by spreading the load across a larger surface area.
• V66 Pilot-operated check valves are utilized for temporary load holding.
• Where long periods of load holding are required, consider Enerpac mechanical lock nut cylinders and/or utilizing cribbing.

4 Point Set-Up Using 4 Single-Acting Cylinders and the NEW Enerpac Split Flow Manifold

The above picture shows an alternative 4 point set-up that utilizes the new Enerpac Split Flow Manifold (SFM). The SFM works by distributing an even flow rate to all lifting points ' regardless of the load distribution across the lifting cylinders. SFM's features and benefits are shown below;

• Load compensation valves for synchronous lifting and lowering of heavy loads
• Even flow rate from all outlets regardless of load distribution across the hydraulic cylinders
• SFM42 can be used for both single-acting and double-acting cylinders for greater versatility.
• Gauges installed on all outlet ports for understanding load distribution across jacking locations.
• Assists with control of synchronous movements when either lifting or lowering operations.

Split Flow Pumps for Multiple-Point Synchronous Lifting Operations

Split flow pumps offer many benefits for large-scale multi-point jacking applications. For lifting and lowering applications with multiple points, split flow pumps are a far better alternative than using independently operated pumps.

Depending upon the chosen configuration, they can offer extreme control accuracies of +/-1mm per leading and lagging jacking cylinders. See available options described below,

Standard SFP-Series Split Flow Pumps

When synchronization of 4% maximum is acceptable, Standard SFP Series Split Flow Pumps provide a safe and economical solution.

If you need more than 8 lifting points, they can be upgraded to network with additional split flow pumps ' increasing the number of jacking locations up to an impressive 32 units!

• Available in 2,4,6 or 8 split-flow outlets
• Individual or simultaneous operation for valves with advance/hold/retract functionality
• Flow rates per outlet ranging from 0,27 ' 4,2 l/min at 700 bar
• Suitable for both single and double-acting cylinders
• Load compensation valves control both the lifting and lowering operation with up to 4% accuracy between the leading/lagging cylinders
• Available with 20, 40 or 150ltr capacity reservoirs.

Programmable Logic Controlled Split Flow Pumps

For extreme accuracy applications, SFP-Series split flow pumps can be upgraded to become PLC-controlled synchronous lifting systems. This increases the SFP's capabilities to become an accurate synchronous lifting/lowering system that's capable of achieving +/-1mm accuracy from the leading/lagging hydraulic cylinder.

This upgrade utilizes external stroke sensors which communicate with the master control box to provide continuous feedback. Similarly, the upgraded SFP-Series Split Flow Pumps can also be networked to achieve an impressive 32 point synchronous lifting system ' without the need to change any of the standard SFP hardware.

As well as the above impressive capabilities, the SFP systems offer the additional elements shown below,

• Control of multiple split-flow pumps with one master control unit
• Pumps can be closer to the lifting points ' resulting in shorter hose lengths for increased accuracy.
• All lifting points synchronize within +/- 1mm accuracy
• Network control boxes expand the number of lifting points by combining up to four split flow pumps together. This simplifies lifting operations by using a single operator station
• Plug and play synchronous lift upgrade kits limit your initial investment, and provide everyday flexibility to tailor the controls to suit the application.

Application examples requiring synchronous lift systems include:

' Bridge deck lifting for bearing maintenance
' Stage lifting in construction and shipbuilding
' Skidding ' to move structures and buildings
' Levelling of large constructions like wind turbines

Want more information on dual hydraulic cylinder? Feel free to contact us.

Do you need help knowing which hydraulic cylinder will fit your machine? Could you use some guidance on choosing the right cylinder for your specific application? In this article, we will provide you with all the identifying information you will need and each step to take to measure before choosing which hydraulic cylinder to buy. Avoid returns, and get it right the first time!

Hydraulic cylinders are utilized in various applications and can be found on many machines, from scissor lifts to skid steers, tractors, and log splitters. As such, finding the cylinder you need can be a challenge. Whether this is your first time buying a replacement cylinder or you're DIYing a new log splitter, we're here to help you choose the right hydraulic cylinder for your project.

Hydraulic Cylinder Components

Before we discuss your options, let's quickly review the basic hydraulic cylinder components so that we can all understand the terminology in our buying guide.

• Barrel: The barrel is the tube inside which the piston and rod travel. The bore, or the fit of the barrel, is the measurement of the barrel's inner diameter (ID).
• Rod: The rod is the solid steel column that extends and retracts, displacing part of the hydraulic fluid's volume. Rods are often chrome-plated to reduce friction. The rod measurement is the OD (outer diameter), which is easy to measure with a caliper.
• Piston: The piston is the disk that separates the two chambers within the barrel. Fluid acts on at least one side and pushes the piston. You probably don't need to worry about the piston measurements when buying a cylinder.
• Guide rings: Guide rings, wear rings, and support rings are different names for the same thing. They should be made from a material tough enough to support the piston and soft enough not to damage the inside of the barrel.
• Internal wear rings: Internal wear rings support the rod's movement.
• Piston seal: A piston seal prevents fluid from escaping. A worn-out seal is one reason the cylinder may only need to be overhauled rather than completely replaced.
• Base: The base, or cap, seals the end of the cylinder barrel, allowing pressure to build up to push the rod.
• Gland: The gland plays a vital role in maintaining the rod's position. RuggedMade welded cylinders feature threaded glands to handle higher pressures.
• Wiper seal: The wiper/dust seal can be seen from the outside, preventing dust and debris from getting inside.
• Mounts: A cylinder needs to be mounted with at least two points of contact. You can find several types of mounts, including ball/swivel, pin-eye, clevis (fixed at one end or thread-on or welded at the other), and cross-tube. Most cylinders have mounts at the base, but trunnion and flange mounts do not. Usually, cylinders are mounted using two pins, but some use bolts, like the flange mount. If the pins are discovered to be worn out when replacing a cylinder, replace them, too.
• Ports: The port is the hole in the cylinder that allows fluid to flow into and out of the barrel. Two types of ports are typically used in America. The first is NPT (national pipe tapered), which plumbers have used for decades. The second is ORB (O-Ring boss).

Watch our Parts of a Hydraulic Cylinder video for a visual guide to these hydraulic cylinder components.

How to Choose a Hydraulic Cylinder for Your Project

Our video guide, How to Measure a Hydraulic Cylinder, demonstrates the step-by-step process of measuring a hydraulic cylinder.

Questions to Consider

Many factors must be considered when buying a new hydraulic cylinder, like the type of mounts required. The mounting type affects the cylinder's alignment, operation, and ability to handle loads. Common types include flange, clevis, or trunnion mounts.

The cylinder's speed and force requirements will dictate the size and type of the cylinder and the hydraulic system's power needs.

If you're replacing a worn-out cylinder, what are the specifications of the old one? Bore size, rod diameter, stroke length, and pressure rating are key to finding an exact match or an upgrade.

Do you need a single-acting or double-acting cylinder? The choice depends on the application and whether it needs to exert force in one direction (single-acting) or both directions (double-acting).

Types of Hydraulic Cylinders

Identify the type of cylinder you need. RuggedMade offers the two most common types of cylinders used on various machines and across many applications: tie-rod and welded.

On RuggedMade's welded cylinders, the base is welded to the end of the barrel and is not meant to be removed. The cap at the gland end (where the cylinder rod moves in and out of the barrel) is threaded and can be removed.

On tie-rod cylinders, both the base and gland end can be removed. The gland and the base end cap are held together against the barrel using four threaded tie bolts or rods. These long bolts run the entire cylinder length and act like a vice holding the barrel caps together.

How to Measure a Hydraulic Cylinder

Several measurements describe a hydraulic cylinder. When replacing a hydraulic cylinder, accurately measuring the old one's dimensions will help ensure you buy the right one. One thing to keep in mind is that most manufacturers standardize measurements to the nearest whole or half inch. Four important measurements are used when sizing a cylinder.

We'll start with the hydraulic cylinder stroke length calculation because the question we hear most about sizing cylinders is, "What is the stroke length of a hydraulic cylinder?".

Stroke is the distance the rod and piston travel from the fully retracted to the fully extended positions. The simplest way to determine the stroke length is to measure the distance between the rod end pin center and base end pin center when the rod is fully extended and then when the rod is fully retracted. The difference between these two measurements is the cylinder stroke length.

For example, if the extended length is 18.25" and the retracted length is 14.25", then the cylinder has a 4" stroke (18.25 minus 14.25 equals 4).

If measuring from the pin center is too difficult, use the outer edge of each pin, but make sure you're looking at the same side for both (right to right or left to left, but not right to left).

If you plan on disassembling a cylinder, remember to measure the stroke first.

The next measurement is the cylinder port size.

As we said above, there are two commonly used types of ports: NPT (and NPTF) and ORB. The NPT type has tapered threads, while the ORB type has parallel threads. You can use a thread gauge and a thread gauge chart to help identify the thread standard. Measuring the size is tricky because the physical dimensions don't exactly match the nominal dimensions specified by the manufacturer.

If replacing a cylinder, you want the new cylinder to have the same size ports and, ideally, the same thread type. If you cannot find an exact match to the original port thread, you can use an adapter.

Another important measurement is the cylinder bore ID or the inner diameter of the barrel. The bore ID determines how much force the cylinder can generate. There are two ways to measure the bore ID.

The first method is to measure the outside width of the cylinder barrel and then subtract the width of the cylinder wall. For example, if the outside barrel width is 3.5" and the cylinder wall is 0.25", the bore ID is 3".

A more precise method involves disassembling the cylinder. This can be a messy process, but it allows you to use a caliper to measure the barrel's ID.

The final measurement is the cylinder rod OD. This is a straightforward measurement: Use a caliper to measure the outer diameter of the rod OD. Note that some cylinders have a tapered rod end.

Other Factors to Consider When Choosing a Hydraulic Cylinder

When a clevis mount is threaded onto the end of the rod, the mounting dimensions may be changed, but the stroke doesn't change. It's the stroke measurement that matters most. When you can't find an exact match, a close match may work fine, but the stroke measurements must match.

Some mounts are designed to be greased, so make sure the new one is greased, too.

If you're curious about how changing the rod's size can change a log splitter's cycle time, check out our experiment in this video.