Choose a Concrete Mixer
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How to Choose a Concrete Mixer

For large-scale construction and repair work, auxiliary equipment is indispensable. For example, if you decide to build a country house or cottage, or lay paths on your personal plot, you will need a lot of concrete or cement mortar. There are two ways out of this situation: buy ready-made concrete or make it yourself in a concrete mixer.

If you decide to buy your own concrete mixer, then first you should familiarize yourself with the design features of different models, their performance and functionality. A careful approach to the choice of a concrete mixer will allow in the future to complete all work on the site in the shortest possible time.

Concrete mixer device and principle of its operation

The concrete mixer is designed for homogeneous mixing of building mixtures and preparation of cement mortars, without resorting to physical force. Such a device is completely autonomous, it greatly simplifies the work on the construction site and avoids both tedious manual mixing and the use of mixers. All you need to do is load the mixture and water in the required proportions inside the drum, the mixer will do the rest.

Also, the concrete mixer is useful for constantly mixing the construction mixture to prevent it from seizing. In this case, purchasing your own device is much more profitable than buying a ready-made mixture, with the volume of which it is easy to make a mistake.

Concrete mixer design

There are several main parts in a concrete mixer.

Drum (pear). This is a container into which the necessary materials are loaded, where they are mixed. In order for the solution to mix evenly and without seals, there are special blades in the drum that break the lumps of the dry mixture. Depending on the type of “pear” design, the blades can be either static or rotating with a separate drive.

On our site, various volumes of drums are presented – from 63 liters (for small jobs and private needs) to 465 liters (such concrete mixers are beneficial to use in large-scale construction to serve a large team of workers).

Frame (frame) – a structure that keeps the concrete mixer in a static state. The frames are made of reinforced metal pipes and other materials that can support the weight of the heavy mortar in the drum. The presence of wheels on the frame of the concrete mixer makes it easy to move it, but stationary devices are more productive.

Engine. The drums in modern concrete mixers are driven by electric motors or internal combustion engines. The latter option allows you to work away from power lines, but it cannot be used in closed rooms due to the presence of exhaust gases, and such devices are also quite noisy.

Electrically driven concrete mixers are much quieter, more reliable, cheaper and do not require regular maintenance.

The principle of operation of concrete mixers

Classification of concrete mixers according to the principle of operation:

Forced type of mixing – the drum of the mixer remains stationary, only the blades installed in it rotate.

This type of mixing is considered to be of better quality, it makes the mixture homogeneous, but such concrete mixers are very expensive and are used mainly in large-scale production. It will also cost “a pretty penny” and their repair if a breakdown occurs. Used for fine-grained mixtures.

Gravitational type of mixing – mixing of the mixture occurs during its collapse in a rotating drum under the action of gravity. At the same time, special blades are fixed on the walls of the drum, which prevent the mixture from slipping and ensure high homogeneity of the solution.

It is used in most modern concrete mixers, including those presented on our website. Such mixers are much easier to operate, less likely to fail, and the cost of repairing them is much less than that of forced ones.

If you are planning the construction of a country house or cottage, it is better to take a closer look at gravity concrete mixers. They are not only cheaper, but also handle coarse blends well.

Concrete mixer drum rotation

In concrete mixers of the gravitational type of action, rotation to the drum is transmitted from the engine in two ways:

  • with a gearbox
  • with a gear wheel (crown)

A gearbox is a special unit in which a gear mechanism is located that transmits rotation. The gearbox itself is covered with a special casing that prevents sand and debris from entering the system.

This type of drive requires gentle handling. If the gearbox fails, it may be necessary to replace the entire unit, or even the engine along with it. In this case, the cost of repairs can be comparable to the price of a new concrete mixer.

The girth drive is simpler and more reliable. In this case, a large gear wheel (crown) is installed on the drum of the concrete mixer. The drive gear on the engine clings to the teeth of the wheel and the drum is set in motion.

Such systems are much cheaper than geared ones and are easier to repair. Most often, a crown mixer can be repaired with your own hands at minimal cost.

The wear of the teeth of the crown occurs due to the ingress of sand, cement and other fine-fraction elements, which are abundant in any construction site. To exclude the breakage of the crown or postpone its wear, you need to carefully select the material from which it is made.

What to look for when choosing a concrete mixer

If you have decided on the main parameters of the future concrete mixer, you should go to the little things that are no less important when choosing a device.

Drum volume. The performance of the device directly depends on this parameter.
The choice of a concrete mixer should be based on the scope of the proposed work. For example, if you need a device to help you repair or build a small house, then buying a large concrete mixer is not necessary – it just won’t pay off. In addition, a small amount of the mixture in the large drum will mix ineffectively due to the uniform distribution along the walls of the device.

On large construction sites, on the contrary: a small amount of “pear” will reduce the entire work process to nothing, someone will have to constantly add the mixture and wait until it becomes homogeneous. In this case, the consumption of concrete or cement can exceed the productivity of the concrete mixer.

In order not to be mistaken in your choice, use these simple tips:

  • if you are going to perform minor construction work such as plastering walls, pouring screed in small rooms or laying tiles, then a small concrete mixer with a drum volume of approximately 50-60 liters is suitable for you;
  • want a small country house or a major garage? Then a drum with a volume of 65 to 100 liters is suitable for you;
  • concrete mixers with volumes from 100 to 200 liters are suitable for building a cottage or a private house and pouring a foundation for it;
  • devices with a volume of 200 liters and above are used for large houses where high performance and a large amount of solution are required. For example, a team of several bricklayers will need 1–2 cubic meters of mortar per hour.

The volume of the finished mixture at the outlet is usually calculated on 2/3 of the volume of the concrete mixer tank.

From here comes another tip: match the drum volume with the required capacity. In this case, the drive power of the device plays an important role.

Concrete mixer power. The performance of any concrete mixer depends on the ratio of engine power to drum volume. For example, with a large mass of mixture in the drum, a weak engine simply will not be able to turn the container at the required speed, which will reduce the speed of operation and may lead to damage to the device. To avoid this, think about the expected amount of work in advance.

For example, for concrete mixers with a tank volume of 60 to 100 liters, a power of 500 W is more than enough. True, in professional construction, such devices will only slow down production, so more powerful concrete mixers will be required.

For concrete mixers with a “pear” volume over 200 liters, engines with a power of 1500 W or more are suitable. This will ensure maximum productivity even when the tank is fully loaded with the mixture and will contribute to the continuous work of the construction crew.

Mains voltage. For household concrete mixers, the voltage of a regular electrical network is sufficient – 220 V. For more powerful professional devices, power is required from a three-phase network with a voltage of 380 V, so carefully study the description of the product when purchasing. Indeed, in the absence of the required voltage in the electrical network on the site, you will have to look for a way to power the concrete mixer from powerful generators, which is not always possible.

Drum rotation frequency. The speed of stirring the solution inside the container depends on this value. The larger the drum diameter, the lower its minimum rotation speed should be.

Why is drum speed important? Many construction experts point out that to make high-quality concrete, it is not enough to mix the mixture in the right proportions; for this you need to mix it at a certain speed. At a very high or too low mixing speed, the strength of the future mixture changes. Many, especially foreign manufacturers of cement and other building mixtures indicate on the packages the recommended mixing speed in the drum, which should not be neglected.

The blades inside the drum can be stationary or rotating. An additional drive is used to rotate the blades – such a mechanism can be considered less reliable than with fixed blades. The more blades, the more evenly and faster the building mixture will be mixed.

Additional wheels on the frame will allow you to easily move the device around the construction site. But it should be borne in mind that such concrete mixers are slightly less productive than stationary ones. In addition, the wheels must be equipped with a reliable locking system to prevent accidental movement of the device during mixing.

Noise level. Pay attention to the maximum noise generated. If you are going to work in apartment buildings, then it should be minimal, so as not to displease neighbors. But for work outdoors, you can choose a more powerful device that will be a little more noisy.

The choice of a concrete mixer directly depends on the tasks. If you take a little time to study the features of the models, then you will definitely choose exactly the one that you need. Enjoy the shopping!

Sources

https://bestpavingtools.com/concrete-mixers
https://en.wikipedia.org/wiki/Concrete_mixer
https://gharpedia.com/blog/types-of-concrete-mixer/