Chip crushers: types, prices and application features

Wood chips are a highly sought after material that is suitable for a variety of applications.

It is obtained mainly as waste from wood processing.

The types of wood chips for different applications, which are determined by the shape, size and type of wood, can vary greatly.

In this article we will talk about the various equipment that is used to produce wood chips.

We will also talk about the influence of the type and configuration of equipment on the characteristics of chips.

Differences between woodchips and sawdust and shavings

To choose the right equipment, you need to understand how wood chips differ from other types of wood .
We have already talked about sawdust and shavings, so we will continue to talk about the differences between wood chips.

It is generally accepted, although this is not stated in any regulatory document, that sawdust is very fine crushed wood , the average length of each particle is 1–2 mm, and the width and thickness are tenths of mm.

The chips are somewhat larger , the average length is 20–30 mm, and the thickness can reach 1 mm. Anything that is noticeably larger than the average chip in size (with the exception of wood wool) can be classified as wood chips.

Therefore, changing the settings of the equipment with which chips or shavings are obtained makes it possible to produce one or another product. Because of this, in stores the same unit is called either a machine for producing chips or a machine for producing chips.

However, there is another difference between these products. It lies in the fact that chips, regardless of size, appear as a result of cutting or crushing wood , which is why they receive a certain shape.

Therefore, when the machine produces shredded wood using this method, which is more similar in size to chips, formally these products will need to be considered chips.

Differences by engine type

On sale you can find a variety of crushing plants for professional crushing of large quantities of wood chips. They may differ depending on the type of engine used. Today there are several different equipment options that use different engines.

Electric wood chippers

Devices of this type have a relatively low cost and require minimal costs to process large quantities of wood. At the same time, the disadvantage of the equipment is that they operate exclusively from a generator or AC mains.

Sufficiently powerful models of electric crushers can be additionally equipped with a five-pin plug or terminals for connecting to the network. Small equipment is equipped with a cord or socket that has a special lock. In order to be able to connect the crushing machine to a simple outlet, you should additionally purchase a special cable.

Gasoline and diesel wood chippers

ICE or internal combustion engines can be installed on a variety of units that can be used to chop wood into chips for smoking. The difference between the engines is only in power. Small crushers are equipped with not very powerful engines that run on gasoline. The cost of such equipment is much lower than diesel engines.

If we talk about professional machines, then only those engines that have very high power are used.

It is worth noting that the main advantage of such motors is that the equipment can be used to work in a variety of places and there is no need to look for a source of electrical energy.

If we talk about the disadvantages, the cost of processing the same volume of raw materials will be much higher than in the case of electric models.

This can be explained by the fairly high price of fuel and additional costs for equipment maintenance. Oil, spark plugs and filters need to be changed regularly so that chipping machines can function fully.

Wood chippers powered by PTO

Such devices are usually used to process very large volumes of raw materials. The equipment is manufactured as a mounted device, which, if necessary, is installed on the tractor.

• The cutting tools in this situation are either disk or drum chippers.
• It is worth noting that drum chippers are used several times more often.
• The diesel engine of the tractor has a huge torque, while the PTO has a low rotation speed.
• The most important advantage of such equipment is that it has a relatively low cost.
• At the same time, the manufacturer does not spend money on purchasing a motor and does not make the design too complicated.
• Chip cutters powered by a PTO are considered the most mobile equipment. In this case, it is customary to use a tractor as a mobile platform.

Equipment for the production of

Equipment that is suitable for producing wood chips includes :

• drum chipper;
• rotary chopper;
• hammer crusher;
• shredder

Drum chipper

This is a multifunctional unit that is used both for producing wood chips and for producing various types of shavings.
The basis of this machine is a drum with a diameter of 30–150 cm, on which 4–8 cutting and 4–20 separating knives are installed .

In addition, the machine is equipped with a drive that feeds the wood to the drum and prevents it from flying out.

If, after separation from the total mass of wood, the chips are too large in size, then the knives drag them along the sieve until they either split or are cut by additional knives mounted on the body.

The size of the finished product depends on:

• drum diameter;
• number of knives;
• wood feed speed;
• drum rotation speed;
• angle of entry of knives into wood.

The larger the diameter of the drum, the more time passes between cuts at the same rotation speed, which means the thicker the cut material will be.

In the same way, the thickness of the material is also affected by the number of knives , so if it is necessary to obtain thick chips, half of the knives are removed (every other one, so as not to upset the balance).

feed speed and drum rotation speed on cheap machines are not adjustable , but on homemade or expensive devices this is possible, thanks to which you can change the size of the chopped wood within a wide range.

The angle of entry of the knives into the wood determines the size and shape of the finished product. When it is 90 degrees, that is, the wood fits right in the center of the drum, then the cut occurs strictly along the grain.

Moreover, first, separating knives act on the wood, cutting deep vertical stripes in it, then cutting, separating a thin layer , which immediately falls apart into strips , the width of which is equal to the distance between the separating knives.

Due to their small thickness, these strips break into narrow fragments corresponding to annual rings, because the strength of the connection of the wheels to each other is much lower than the strength of the wood inside one ring.

As the angle of entry of the knives into the wood decreases, the shape of the final product also changes.

After all, the smaller the entry angle, the greater the length of the annual layer caught in the cut fragment, which means the greater the width of the piece separated from the cut plate.

In this case, the thickness of each piece turns out to be noticeably less than its width , due to which the shape of the finished material fully satisfies the requirements for wood chips for the production of wood concrete.

Therefore, by changing these parameters, it is possible to obtain both wide chips suitable for the production of OSB and chips similar to rectangular chips for smoking or infusing alcohol.

The drum chipper can process any long wood whose diameter does not exceed the throughput capacity of the unit.

Therefore, most often the machine is used for chopping round wood, that is, debarked or unbarked trunks and thick branches.

In addition, the machine is also suitable for shredding long scraps , however, there is a limitation on the minimum thickness due to the peculiarities of the feed mechanism.

This unit is not suitable for processing used boards and logs , because an undetected nail will damage the knives and sharply reduce the efficiency of the mechanism.

Rotary chopper

The basis of this device is a heavy and thick rotor , which acts as a flywheel and is a platform for installing knives (usually 3 pieces).

The wood is fed through a special chute at an angle of 50–80 degrees, which increases the width of the cut annual rings, and hence the size of the crushed product. A counter knife is installed between the rotor and the housing on the wood entry side , facilitating the operation of the device.

After all, a chopping knife moving from above and a counter-knife fixedly mounted on the body create an analogue of scissors and not only increase cutting efficiency, but also eliminate wood from being pulled under the rotor and jamming of the unit.

Typically, such a grinder is used in tandem with a hammer crusher, installing them in a common housing. This combination completely eliminates the plates with several undivided growth rings, resulting in a needle-shaped finished product.

If there are no strict requirements for the shape and width of the chips, then a rotary chopper is used without a hammer crusher.

The main purpose of this device is processing cut branches , which is why such devices are often called garden shredders.

The unit is also suitable for processing thin trunks and various scraps of any length, the only limitation is related to the cross-section of the wood. After all, the gutter rests on a window with a relatively small cross-section (from 10x10 cm for garden ones and up to 30x30 cm for industrial ones).

Hammer chip crusher

This apparatus consists of a shaft with support disks, between which there are fingers that hold hammers, that is, rectangular steel plates that rotate freely around their axis.
Also, fender plates are welded to the shaft.

When the rotor disk has completely spun and its rotation speed has become constant, the hammers , due to the action of centrifugal force, form a three-rayed star .

Any change in the rotation speed also leads to a change in the position of the hammers, so they hit the impact plates designed for this purpose either in front of them or behind them. Moreover, the impact force is sufficient to separate the wood along the boundary of the annual rings, but not sufficient to damage the fibers.

Typically, such a crusher is used in conjunction with a rotary shredder , because the impact energy of the fingers is not enough to separate large fragments of wood.

Therefore, most often a complex consisting of a shredder and a crusher is used for the production of wood chips.

Indeed, despite the extremely low cost compared to a drum machine or shredder, such a complex produces chips that, in their size and shape, are ideal for the production of wood concrete.

Shredder

Devices of this type consist of a shaft with special hooks or teeth that pass through grooves intended for them. When wood of any shape enters the work area of ​​the shredder, the hooks crush and break it into pieces the width of which is equal to the width of the hooks.

Twin-shaft units are more efficient , because each shaft is both moving in one row and grooves in another row.
Thanks to the enormous torque with which the shaft rotates, the shredder easily crushes wood of any species .

Even a nail caught under the hooks does not affect their condition, because the shredder’s teeth do not cut or plane, but crush the wood, so small defects on their surface do not affect the result in any way.

More expensive and modern models of shredders are equipped with various systems that correctly position the wood, because the size and shape of the chips directly depend on the position of the wood relative to the shafts .

When the wood fibers are located along the shafts, crushing occurs at the joints of the rings, and the chips are of maximum quality. If the material enters the chipper as it turns out, then the chips turn out to be of different types.

Pros and cons of woodchip machines

Industrially produced machines for wood production differ from each other in power and operating principle. Disc crushers have the simplest design and lowest operating efficiency. Despite this, they are currently the most in demand. The advantage of such equipment is the ease of repair and maintenance.

Drum crushers are considered the most efficient in operation. They have a large loading window into which an impressive amount of wood prepared for production can be placed. Such equipment is suitable for processing absolutely any type of raw material. It rarely fails.

Chip production line

Screw equipment is least suitable for the production of smoking chips. It crushes the wood into too small fractions. All types of equipment can have their own engine or be powered by other equipment. The latter version of the equipment is more expensive to purchase and operate.

Models of wood chippers and their prices

The cost of complex units, such as drum chippers or shredders, depends on many factors , so in the table we have included links to the websites of the manufacturer or seller, where you can find out information about the price of wood chippers depending on the desired configuration:

Types of machines for producing smoking chips

In large smoke chip production plants, special lines are installed. They have high performance.

The set of equipment for the production of smoking chips includes:

• Shearing machines or crushers.
• Bunkers for collecting wood chips and conveyors.
• Boilers or chambers or drum dryers for wood.
• Gas generators.

The choice of equipment depends on the need for smoking chips. Installations designed for its production can also produce other types of chips. For example, decorative.