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How Does a Conical Spring Work?

Conical Spring | KB Delta

A spring provides energy and transfers it through a series of spirals. They can be bought off the rack or manufactured to fit your specifications.

A conical spring is used when a machine or object needs a large end in a bore and the small end moves over the rod. As the name suggests, they are cone shaped compression springs which perform best when providing a constant spring rate. Springs come in different pitches, which mean the spiral coils nest inside each other when it is depresses so it squashes down to a very low profile.

They are also known as “cone” or “tapered” springs.


Conical Spring Design

These springs are designed so they are tapered and go from tight, small curls at the top of the spring to wider and wider coils until it reaches the widest coil at the base. Each coil is slightly larger than the last so they fit, or “nest”, together neatly.

Generally, a spring is designed so it changes shape when force is exerted on it.

Since the early 1500s when coiled springs were first used, their design has hardly been changed. The industrial revolution in the 18th century saw mass production of these springs.

Although they look like a simple design, there is a lot of mathematical equations and calculations to make sure the spring performs as it should do. While these used to be done by hand, nowadays the calculations are managed by computer software which makes the whole process simpler.


Common Conical Spring Materials

There are a few different types of materials that can be used to create springs but the most common is steel alloys. Conical springs can also be created from oil-tempered low carbon, stainless steel, chrome silicon or chrome vanadium, and high carbon alloys, which are used for making musical instrument wires.

As well as these steel alloys, a variety of other metals can be used to create a conical spring. Copper alloy, phosphor bronze and titanium, for example.

Ceramic materials have been used in high temperature environments, though these are less common. Scientists are also testing the use of glass fiber materials for springs.


Lifespan of a Conical Spring

As with most parts and components, the lifespan of a conical spring depends very much on the quality of the design and manufacture.

The most common cause of spring breakdown and faults is corrosion. This can be from outside elements or just from leaving your unit outdoors where damp and grit can get into the moving parts.


Benefits of a Conical Spring

Conical springs differ from other springs in several ways and these have benefits, such as:


  1. They have a smaller height when decompressed – Unlike other springs, a conical spring has each spiral fitting inside each other so when it is completely compressed, the spring will only be as high as the thickness of the wire or material you use to create it. This is particularly helpful if the machine you are installing it in is limited in space.
  1. Increasing force rate – Instead of other compression spring designs, conical springs have an increasing force rate instead of it staying constant. This means that the larger coils at the bottom force the smaller coils upwards in a consistent motion.
  1. Stable – Conical springs are very stable due to their design. The smaller “top” and wider “bottom” mean they won’t buckle as easily.
  1. Stops vibration – The way a conical spring is designed means it reduces vibration and shaking because the spirals are all of the same shape and design. As the coil depresses, the vibration is spread through larger and larger coils which helps to keep the wobble to a minimum.


Risk Associated with Conical Spring Failure

Springs need to be designed and manufactured carefully to make sure they don’t break or fail. Conical springs can be set up in many different designs and sizes depending on the task at hand.

Springs can fail when there is too much pitch in a single coil that results in more stress put on that particular area.

If a spring breaks, due to the tension it is under, it will immediately try to return to its original state. In a compressor valve, this can cause damage to other components. If a conical spring is being used in an open area, the force of breakage could cause it to fly into the air or hit other nearby objects.

Another failure could be that the manufacturing process hasn’t been precise enough and the coils do not fit inside each other correctly. This means the largest coil will spread and bend which could cause fractures and breakage.


Managing Conical Spring Failure

To ensure your conical spring remains operational you should make sure it is regularly inspected and maintained. A powder coating can also help protect the spring from corrosion.

When choosing a conical spring you should also make sure it is quality assured and from a manufacturer that regularly tests the end product in random batches, to ensure the highest quality.

The best course of action if you find a spring has failed is simply to replace it. A repair can sometimes be possible and the spring would have to be put back into exactly the original shape or it will break again.


Choosing Replacement Conical Springs

If you need to replace the conical spring in your compressor unit, you should take a look at the following elements.


  • Free height – This is the height of the spring when it is not in use or under any pressure. Look at the free height and make sure it fits your unit.
  • Compressed height – Similarly, you should look at the compressed height. In a conical spring, this is usually the thickness of the wire or material it is made from.

Before you start maintenance or repair on any of your equipment, you should always read the instructions or manual to make sure you are fully aware of the workings of your particular unit.


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