How to Configure an NFPA Tie-Rod Cylinder for Your Application
NFPA tie-rod cylinders are commonly used in industrial equipment because their standardized dimensions make them easier to specify, install, service, and replace. But choosing an NFPA cylinder still requires more than selecting a bore and stroke.
At Hydraulic Cylinders, Inc., our NFPA tie-rod cylinders are configured to your requirements. Each product page functions as a cylinder configurator, allowing you to build a cylinder from an established design by selecting the specifications and options required for your application.
The process starts with choosing the right NFPA cylinder series.
Start With Hydraulic or Pneumatic
The first decision is the type of power your equipment uses.
Hydraulic NFPA cylinders use pressurized hydraulic fluid and are typically selected for applications that require higher force and load capacity.
Pneumatic NFPA cylinders use compressed air and are commonly found in automation, manufacturing, positioning, clamping, packaging, and other repetitive-motion applications.
HCI offers five configurable NFPA tie-rod cylinder designs:
- Series 3 Standard-Duty Pneumatic
- Series 3 Large-Bore Pneumatic
- Series 4 Heavy-Duty Pneumatic
- Series 5 Standard-Duty Hydraulic
- Series 6 Heavy-Duty Hydraulic
Once you select the appropriate cylinder design, the configurator walks you through the specifications needed to build the cylinder.
Select the Bore Size
Cylinder bore is one of the primary factors that determines available force.
For hydraulic cylinders, force is based on piston area and hydraulic system pressure. For pneumatic cylinders, the same basic principle applies using compressed air pressure.
A larger bore produces more force at the same operating pressure, but bigger is not always better. The cylinder needs to match the actual load, available pressure, equipment space, and required operating speed.
HCI’s NFPA product range includes bore sizes for standard industrial applications as well as large-bore pneumatic requirements.
Determine the Required Stroke
Stroke is the distance the cylinder rod needs to travel from its fully retracted position to its fully extended position.
For a replacement cylinder, this may already be established by the existing unit. For a new application, the required machine movement will determine the stroke.
The stroke should provide the necessary travel without creating interference or exceeding the mechanical limits of the equipment.
Choose the Rod Size and Configuration
Rod diameter affects cylinder strength and stability.
Applications involving long strokes, pushing loads, higher forces, or side-loading concerns may require a larger rod diameter. Rod size can also affect the available retract force in a double-acting hydraulic cylinder.
Depending on the cylinder series and application, additional rod configurations may also be available.
Select the Mounting Style
NFPA standards define many common mounting arrangements, which is one of the reasons NFPA tie-rod cylinders are widely used in industrial machinery.
The proper mounting style depends on how the cylinder transfers force into the equipment.
Common arrangements include:
- Side mounts
- Flange mounts
- Tie-rod mounts
- Pivot mounts
- Trunnion mounts
The mounting configuration needs to match both the equipment and the direction of the applied load.
For replacement applications, matching the existing mounting dimensions is especially important.
Configure Ports and Port Locations
Your cylinder also needs to connect correctly to the hydraulic or pneumatic system.
Depending on the cylinder design, the configurator may allow you to select items such as:
- Port type
- Port size
- Head port location
- Cap port location
Port orientation can be especially important when space is limited or existing hoses, tubing, valves, or fittings need to be reused.
Consider Cushioning and Other Options
Many applications benefit from additional cylinder options.
Cushioning can help control piston deceleration near the end of the stroke, reducing impact in applications with higher speeds or heavier moving loads.
Other available options can vary by cylinder series and may include different seals, rod treatments, sensing options, rod accessories, and application-specific features.
The goal is to configure the cylinder around how the equipment actually operates rather than selecting unnecessary options.
Configuring a Replacement NFPA Cylinder
If you are replacing an existing NFPA tie-rod cylinder, much of the information needed for the configurator may already be available on the cylinder itself.
Start by gathering:
- Manufacturer
- Model or part number
- Bore
- Stroke
- Rod diameter
- Mounting style
- Port size and location
- Operating pressure
- Any special options or features
You can also take clear photos of the cylinder, mounting points, ports, and identification tag.
NFPA standards can make cross-referencing easier, but you should still verify the complete cylinder configuration before ordering a replacement.
Build Your NFPA Tie-Rod Cylinder
HCI’s NFPA cylinder configurators give you a starting design and allow you to specify the cylinder around your application.
Whether you need a standard-duty pneumatic cylinder, large-bore pneumatic cylinder, heavy-duty pneumatic cylinder, standard-duty hydraulic cylinder, or heavy-duty hydraulic cylinder, you can select the appropriate series and configure the required specifications online.
If you are unsure which cylinder series or options you need, our Hydraulic Cylinder Specialists® can help review your application or existing cylinder.
