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How to Determine the Quality of Barrel Springs in Compressors

Using high quality compressor parts is essential in manufacturing production. Because of this, compressors use different types of springs, including barrel springs, to aid in their functionality. Where one fails, the other makes up for it.

Barrel Springs for Compressors - KB Delta

You’ll find barrel springs in a couple of machines and their level of performance will be determined by a number of factors.

These factors can be summed up in knowing how to determine the quality of barrel springs in compressors.

If that has posed any difficulty in the past, it’s nothing to worry about since we’ve outlined the features you must prioritize if you must find a high-performance barrel compressor spring.


What is a Barrel Spring?

Barrel springs in compressors are round wires that are helically coiled to create a convex or concave shape.

Either shape can easily be differentiated from the other using the size of its diameter.

  • Take convex barrel springs, for instance, their physical appearance closely resembles that of a barrel since the diameter of the middle coils is larger than the end coil diameters.
  • On the contrary, concave springs have middle coils that are smaller than the end coil diameters. This type of coil is sometimes said to have a barbell or hourglass shape.

These aside, a barrel spring is a type of compression spring that produces linear force when the center outer diameter is larger than the top and bottom outer diameter.

Barrel springs have the functionality of providing balance and reducing the solid height.

Most end users prefer it over generic compression springs due to is the ability to prevent buckling, reduce space, and provide several shaped configurations that can fit a range of designs.

Some terms associated with barrel springs include:

  • Total Coils (T/C)
  • Active Coils (A/C)
  • Free Length (FL)
  • Solid Height (LH)
  • Inner Diameter (ID)
  • Wire Diameter (WD)
  • Mean Diameter (MD)
  • Large Outer Diameter
  • Small Outer Diameter
  • Open Ends
  • Double Closed Ends
  • Closed and Ground Ends
  • Permanent Set
  • Endurance Limit

In the same vein, a number of industries have come to rely on barrel springs and these are not limited to:

  • Toy industry
  • Furniture industry
  • Automotive industry
  • Drinking bottles where the powder will be mixed with water


Benefits of Using Quality Barrel Springs in Compressors

Before we show you how to determine the quality of barrel springs in compressors, it may even be more helpful to know why utmost care must be given in your selection process.

This is because settling for the right spring made from the right material comes with several benefits.

Some of these include:

1. Buckling Prevention:

A quality barrel spring in compressors can prevent buckling or bowing.

This phenomenon occurs when the length of the spring is four times its width. This, in turn, leads to buckling upon compression.

The center of the string then stretches outward and may shoot away from more pressure being applied on it.

Buckling can be prevented entirely with a good selection of a barrel spring which features a wider shape in the center in comparison to the ends and which helps the pressure to be evenly distributed.

2. Solid Height Reduction:

One of the reasons for settling for barrel springs is their ability to bring about solid height reduction because the force they produce is not always linear.

Since barrel springs do not have design restrictions, there is no solid height conflict; a problem that is prevalent in other compression springs that only produce force in a linear direction.

Here’s what to know:

If your aim is to get a spring whose force requires multiple coils, then these coils will bind into each other when they are compressed.

It will get to a point where they can no longer be compressed, and that point is known as solid height or compression height.

The latter can be eliminated with the use of quality barrel springs that can transform the smaller coils located on the spring’s top and bottom into larger coils at the spring’s center.

3. Resonance and Vibration Reduction:

Quality springs bring about resonance and vibration reduction because as each coil bottoms, there is a uniform pitch and an increasing natural period of vibration.

High vibration of a machine can lead to machine failure, therefore making reduction incredibly important.


Our Compression Spring Line Including Barrel Springs - KB Delta


How to Determine the Quality of Barrel Springs in Compressors

There are several ways to spot out quality barrel springs in compressors that can give you a run for your money.

Consider the following while choosing a quality barrel spring for your compressor.

1. Barrel Spring Material:

Whether it’s a barrel spring, tension/extension spring, variable pitch spring, etc. you need to be on the lookout for the type of material the spring is made of.

This means that you’ll find barrel springs made from different materials in the market. Remember, not all of them have the same level of strength or even corrosion resistance.

  • There’s a stainless steel 302 material, for instance, which is one of the strongest out there and is less susceptible to corrosion.
  • Other materials you’ll find are Beryllium copper and phosphor bronze which are good conductors of electricity.
  • There’s also Nickel to look forward to, and this material can be used in high or low operating temperatures.

2. Diameter

A barrel spring’s diameter is the level of thickness of its round wire.

Terms you’ll find associated with the barrel spring include the small outer diameter. The latter is the thickness of the smallest coil found in the spring’s body.

Keep in mind that the outside diameter will tend to expand as the spring is compressed and that being so, you need to determine where the barrel spring will be used.

Is it in a tube or bore?

Another term of utmost importance is the inner diameter which is the width of the smallest coil’s interior.

It can be determined by subtracting two wire diameters from the small outer diameter.

3. Loaded Height

The load on a barrel spring is defined as the force applied to the spring in order for it to travel.

The loaded height, on the other hand, is the compressed length or height of the spring when a load is placed on it.

Thus, you need to know if the loaded height meets your requirements.

  • Now, if the spring tends to travel further, then more stress will be put on it. Due to this, it will likely lose its strength and degrade in no time.
  • The stress, in this case, is referred to as spring set. If it occurs, the spring will not return to its original length after expansion.

One more way to go is to determine the spring set of your barrel compressor spring with the use of stress calculators and formulas.

4. Special or Standard Compression Ends

Barrel spring end types can be standard ones or specially designed.

For standard ends, you’ll find a combination of open or close and ground or not ground end types.

  • Closed ends mean that the ends are not grounded and they do not come in contact with each other.
  • Closed and Ground Ends, on the other hand, mean that the coils are closed without any pitch at the edges. They are also ground to help the spring remain straight while on a flat surface.

Generally, these end types will have an effect on the spring rate given the constant total of outer diameter, wire size, and total coils.

Ground ends will need a lot of manufacturing effort but when used alongside a closed end design, they can improve squareness of loading force while also reducing buckling.

Due to a combination of end types provided by manufacturers, you need to determine if you need ground and closed ends or ground and open ends.



These are some of the easiest ways to determine the quality of a barrel compression spring.

If you can do that, then it will save you the cost of replacing springs whose functionality have not been taken to the highest level.

With all of these requirements in place, you can be assured that you have gotten the right spring for your compressor and one that will be less susceptible to a breakdown.

All it’ll take is to refer to these requirements each time you are faced with the decision of choosing one barrel spring over another.


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