Vacuum cleaners

Generally, a vacuum cleaner is composed of:

• One or more vacuum motors or turbines
• A tank, or container, where the dust, solids or liquids are removed from the surfaces are collected
• A system of filters to hold the particles vacuumed up inside the tank
• A series of accessories to enable the vacuum cleaner to deal with specific dirt situations

When the motor of the vacuum cleaner begins to function, it activates the rotation of the fan or fans installed on the rotation axis. The rotation of the fans sucks air in from the outside, creating a vacuum inside the tank. Together with the air, the particles that are present are sucked in: if they are large, they settle on the bottom of the vacuum cleaner tank, whereas if they are small, they are trapped by the filter, thus releasing clean air into the room.

Dry vacuum cleaners are able to vacuum dry particles of larger or smaller size that are not mixed with liquid substances.
Meanwhile, so-called wet & dry vacuum cleaners can vacuum liquids of various types, or particles mixed with liquid substances.

It is worth remembering that changing the filter on a wet & dry vacuum cleaner enables it to work as a dry vacuum cleaner, but a dry vacuum cleaner can never be used as a wet & dry vacuum cleaner

Some models are designed to vacuum both solids and liquids simultaneously (Wet & Dry). This is done by directing the air flow which conveys the solids and liquids onto a dynamic (cyclone) separator, rather than directly onto the filter. In this way, the heaviest material is collected at the bottom of the container (liquids and solids can be separated by grilles), while the air with the lighter particles is filtered and returned into the environment.

When cleaning liquids with a vacuum cleaner, or for liquids with no dynamic separation, the paper or fabric filter must be removed and the specific foam filter which protects the float must be fitted.

Conventionally, vacuum cleaners for professional cleaning are divided into:

• Professional vacuum cleaners: machines that prioritize function and reliability and which usually have medium power and versatility, making them suitable for various uses.
• Industrial vacuum cleaners: machines designed for high performance, for industrial use and specific operations characterized by medium/high power requirements. They are used for continuous, heavy duty operations.

We are referring to the power supply, of course. Everything depends on the mains electricity network available in the place of use. Turbine industrial vacuum cleaners with induction motor, both single-phase and three-phase, are perfectly suited to extended application and continuous use. Naturally, the high power levels that are required in certain specific applications necessitate three-phase vacuum cleaners.

There are various characteristics to take into consideration when evaluating a vacuum cleaner, in accordance with the type of use required. The first values to be assessed are the vacuum efficiency, or the combination of motor power, vacuum and air flow rate.

The motor power of a vacuum cleaner is a value expressed in Watts (W) that indicates the maximum power expressed by its motor(s). This is an important value in assessing the absorption of the vacuum cleaner itself, but it is important to remember that this is not directly proportional to the vacuum efficiency; indeed, a motor with reduced power may offer high vacuum performance.
Finally, it is important not to forget that when calculating the power, the number of motors must also be considered; there may be one, two or even three.

The vacuum , also referred to as the water column, is the capacity of the vacuum cleaner to lift the material to be removed; the greater the value, the greater the lifting capacity. When lightweight particles need to be vacuumed, a high vacuum value is not necessary; however, this becomes an important characteristic when the particles are heavy or when the vacuum tube is very long (with potential pressure drops), or when the accessories are very wide in diameter.

The vacuum force of a vacuum cleaner is measured in:

• mmH₂O
• mBar
• kPa

The correct combination of vacuum and air flow rate enables the vacuum cleaner to pick up the material to be removed whilst simultaneously transporting it towards the debris hopper.

The air flow rate is the capacity to convey the lifted material and, when there is a lot of dust, to keep it suspended in the tubes. In a vacuum cleaner, a higher air flow rate with the same vacuum value enables the work to be carried out in less time.

The air flow rate of a vacuum cleaner is measured in:

• l/s
• l/m
• cu.m./h

The correct combination of vacuum and air flow rate enables the vacuum cleaner to pick up the material to be removed whilst simultaneously transporting it towards the debris hopper.

It is important to specify that the tank material must be suited to the substances vacuumed, as chemical reagents or incandescent substances could damage it.
The range of vacuum cleaners by Comac includes tanks in plastic material (polyethylene or polypropylene) or in painted steel or stainless steel.
The flexibility of the plastic material makes vacuum cleaners with polypropylene or polyethylene tanks more resistant to impact, and as such, they are more suitable for applications that require the machine to be moved regularly; indeed, this is the most widely used material in the range of professional machines.
Meanwhile, tanks made from steel are more rigid, but also more resistant to mechanical abrasion and thus preferable for static use; for this reason, the entire range of industrial vacuum cleaners includes steel or stainless steel tanks.

Depending on the type of application and the requirements of the operator, vacuum cleaners of larger dimensions can be mounted on a trolley.
There are two types of trolley: fixed and tilting.
Generally speaking, the tilting trolley facilitates emptying and thus is very convenient in the case of dust or solid debris.
A fixed trolley is recommended when working with liquids, because it is more stable and any unloading is usually facilitated by a convenient tube, without having to lift the tank.

Vacuum cleaners have various stages of filtration.
However, we can divide these into two major families, the main filters and the output filters.

The main filters are also referred to as primary filters and have the task of capturing the majority of the particles and material from the vacuumed air.
Output filters, also referred to as secondary filters, have the task of stopping even smaller particles, in order to return air that is free from pollutants into the environment.

As standard, the Comac models are usually fitted with class L filters. For increased filtering needs (a greater capacity to hold back dust that passes through the filter), there are class M filters. For specific vacuuming operations such as fine dust or bacterial loads, class H (Hepa) filters are available.

It might be necessary to use the vacuum cleaner in areas where there are potentially explosive dusts or gases (these environments are usually called ATEX).
The ATEX (ATmosphere EXplosive) directive came into force in the EEC on 1 July 2003; it certifies the presence of the necessary requirements for vacuum cleaners, turbines and other machinery in accordance with Directive 94/9/EC, so that these can operate safely in potentially explosive atmospheres. The atmospheres defined as posing a risk are in turn divided into various levels of danger for operators, as established by Directive 99/92/EC with regard to the presence of potentially explosive gases, mists and/or dusts in the atmosphere; the end customer is responsible for classifying these areas.
In the case of Comac, the models available have been built to work in zone 22 (dust) and are constructed with AISI 304 stainless steel tanks and antistatic filters that guarantee electrical and mechanical protection for the components and equipment. The machinery and related equipment have been designed to be fully conductive; this eliminates the risk of an explosion being triggered in this specific area.