What are the types of demolition and recycling attachments?
There are as many types of demolition and recycling attachments as attachment tools for this type of work the manufacturers have in their catalogues.
In the following pages, you will find a description of the most common hydraulic ones, although it must be pointed out that there exist other attachments, more used in other sectors, that occasionally can be used for demolition jobs.
In addition, there are mechanical attachments commonly used in demolition job sites, such as buckets and mechanical rippers, but in this guide, only the hydraulic ones will be explained.
Concrete cutters / Crushers
Concrete cutters are attachments specifically designed for breaking concrete.
They are used for very thick concrete wall structures, such as building foundations or for very tough applications, such as long front demolition where the operator has restricted visibility.
Some of the bigger concrete crushers do not close their jaws completely which allows them to achieve wider openings. The focus of these machines is to have the widest possible jaw opening (1 to 3m) to bust thick concrete walls.
Steel / Scrap / Mobile shears
Steel shears are demolition attachments specifically designed for steel cutting.
They are very efficient tools for demolishing steel structures where large steel plates or steel girders must be cut.
A typical design for these attachments is a fixed pair of jaws with a single non-fixed jaw that moves between them, cutting the steel like scissors.
For maximum cutting force, there is a large hydraulic cylinder which makes the frame very long compared to the jaws. Steel shears are equipped with hydraulic rotation and they need two two-way hydraulic connections.
Fixed / Crocked / Bulk / Static pulverizers
Pulverisers (“munchers”) are attachments that cover both, demolition and recycling applications. Their purpose is to crush concrete and separate it from its reinforcement. This way the material can be recycled.
These attachments are capable of reducing large pieces of concrete to smaller, more manageable pieces so that they can be loaded and transported to an onsite crushing unit, where the materials will be recycled. To aid separation for recycling, most pulverisers are fitted with cutting blades, positioned at the back of the jaw, for rebar and smaller steel sections.
Fixed/Crocked/Bulk/static pulverizers are designed to pick up demolished material from the pile. Therefore, they do not have a rotator, which makes the machine lighter for precise movements and shorter to get maximum digging power.
This type of attachment is used for secondary demolition applications.
Straight / Rotating pulverizers
Pulverisers (“munchers”) are attachments that cover both, demolition and recycling applications. Their purpose is to crush concrete and separate it from its reinforcement. This way the material can be recycled.
These attachments are capable of reducing large pieces of concrete to smaller, more manageable pieces so that they can be loaded and transported to an onsite crushing unit, where the materials will be recycled. To aid separation for recycling, most pulverisers are fitted with cutting blades, positioned at the back of the jaw, for rebar and smaller steel sections.
Straight/demolition/rotating pulverizers are designed to crush the material straight from the wall and to pick up the metallic elements.
These attachments are mostly equipped with a hydraulic rotator for easier positioning to a target. It is a particularly good solution for renovations. They can be used either for primary or secondary demolition.
Multi-processors / Combi crushers
Multiprocessors offer the combined functionality of both shears and pulverisers. They have interchangeable jaws to cut steel and crush concrete. So, the use of this type of attachments
reduces the time required for the demolition.
However, is should be noted that, although this is a very practical attachment which works very well, it has its limitations and it cannot shear heavy duty steel sections, this is something that can only be done with a dedicated steel cutting jaw.
There exist two basic types of multi-processors:
- One-cylinder multi-procesor + one movable jaw
- Two-cylinder multi-procesor + two movable jaws
Grapples
This type of attachments is extremely robust and versatile, permitting the execution of a wide range of demolition and recycling activities.
They used for demolishing, material handling, and sorting of all kinds of materials such as rocks, scrap, and other debris.
Grapples can be fitted directly to the dipper arm or via a quick hitch coupler, and it can be used on all types and weights of machine.
Hydraulic hammers / Breakers
Breakers are a powerful percussion hammers, which fitted to a demolition rig, can demolishing concrete structures and asphalt pavements, both outdoors and indoors, and rocks.
They are powered by an auxiliary hydraulic system from the machine, which is fitted with a foot-operated or hand lever valve for this purpose.
It is usually fitted with a hardened ‘point’ or ‘chisel’ which is driven into the material, to be broken, by an internal piston arrangement powered by nitrogen gas for additional piston stroke pressure.
Magnets
A magnet is an attachment that creates a magnetic field below its bottom plate in order to hold metallic materials. Being held, they can be transported to the chosen place and then, with rapid demagnetizing the materials will drop immediately.
The magnet can be hung, by traditional chains, directly to the dipper arm or, as in most cases, from the quick coupler. They are available in a variety of sizes designed to fit most machine weights.
These magnets are used mainly used to separate metallic materials from other type of materials or just to remove rapidly metallic elements from construction jobsites, tunnels and bridges where they can harm pedestrians. Additionally, they are also used to load the vehicles and feed the crushers.
Besides, it should be noted that, although magnets are robust units they never should be used as a demolition element.
Hydraulic rippers
The purpose of rippers is to tear, break and demolishing, stone, concrete, asphalt etc. and it is mainly used for moving away the demolition material to clear an area.
The working principle of these ty of attachments is a combination of active penetration by vibration and ripping out of material. They are fitted with a hydraulic motor, eccentric gear housing, pivot arms and an accumulator to increase break out force.
The whole of the body of the ripper is made of wear resistant material and the ripper arm is fitted with a hardened steel tooth that is replaceable. It can perform both, horizontal and vertical demolition.
Crusher buckets
Crusher buckets are used to crush the demolition material on a jobsite to be used for backfilling for a new building or to be transported. Thus, they are a particularly useful in small to medium demolition applications, providing an on-site recycling resource and boosting the versatility and utilisation of the demolition rig. This type of attachments is simple and robust. It requires low maintenance to ensure long life.
They are powered by the excavator’s standard hydraulic breaker circuit, the crusher buckets use a fixed jaw in the base, with a hydraulically activated hinged jaw in the roof of the bucket. The gap between the two jaws can be set with shims to determine the size of the finished material.
The crushing action is achieved by the hinged jaw being cycled in and out using an eccentric mounted on a shaft across the top of the bucket. This shaft is equipped with substantial flywheels at each end and rotated by a belt from the hydraulic motor. The pressure sensitive reciprocating valve ensures a constant flow of material through the bucket.
Screening buckets
Screening buckets are very use in demolition processes during the site clean-up, as they sort a large number of materials including topsoil, peat, rubble and quarry rock, as well as for backfilling, composting and recycling. They facilitate fast, accurate filtering of large volumes of material.
This type of attachments consists of a trommel screen where hydraulically driven drums rotate inside the bucket and separate oversized material with eccentric discs that allow fines to flow between them.
There exist two types of screening buckets in the market:
- Basic screening bucket
- Rotating screening buckets / Riddling Buckets
Drum cutters
Drum cutters are attachments with rotating drums equipped with picks, strategically positioned around the outer diameter.
The drums are rotated by a hydraulic motor at several hundred revolutions per minute to cut concrete. And the picks that perform the cutting job are wear resistant, exchangeable teeth.
This attachment can be used underwater without modification at depths of up to 30 m.
There exist in the market two basic types of drum cutters:
- Transverse drum cutters
- Axial drum cutters
Pilebreakers
The pilebreaker is used in pillar construction and demolition to crush the concrete part of the pillar without damaging the steel reinforcements.
In addition, its modular design allows a perfect adaptability of the tool to the specific size and shape of the pillars.
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