Types, designs and maintenance of supply and exhaust ventilation units

Buildings of any purpose, size and shape need ventilation. Therefore, there are many types of ventilation systems. The smallest ones are slightly larger than a laptop, and the largest ones will have to be allocated a special room. We will tell you about the difference between a portable ventilation unit and a telescopic unit, why you need a dust-collecting ventilation unit and reveal the secrets of servicing various systems.

Types of ventilation units

Structurally, all ventilation units are divided into monoblock and type-setting.

In addition, in terms of functionality, they can be:

• inflow;
• exhaust;
• supply and exhaust;
• air-thermal curtains.

Supply ventilation unitssuch as "Marta" serve to supply clean air to apartments, offices and industrial premises. The supply air volume complies with the standards and is sufficient to ensure the life of people. The air is filtered before it enters, heated in winter or cooled in summer. Air is supplied to each room through air ducts. Automation controls temperature and humidity indicators, if necessary, turns on heating or dehumidification. In addition to filtering, all additional options are considered optional and are provided at the request of customers.

Exhaust ventilation units They are used to remove exhaust air and equalize the pressure when the supply is in operation. Their design is simpler than supply air, and installation is cheaper. The equipment can be installed in the attic, between slabs or on the roof. Telescopic ventilation units fall into this category.

The most practical settings are supply and exhaust. They are widely used in residential, public and industrial premises for various purposes. The complexity of installation depends on the specifics of the object, and in operation the equipment is quite simple, since the main control function lies with the automatic module.

Air and air-thermal curtains used where it is necessary to separate the zones of cold and warm air, not allowing them to mix. For example, at the entrance to a workshop or a large store. Vertical airflow saves building heating costs by preventing heat from escaping to the outside. The air curtain prevents street dust, fluff and insects from entering the room.

Mobile ventilation units

Mobile ventilation units belong to the category of industrial equipment and are necessary for servicing hard-to-reach places in rooms without ventilation: garages, tunnels, wells, large containers.

A mobile ventilation unit is a module mounted on a frame made of a metal corner on wheels, equipped with a brake and a handle for moving. Air ducts of mobile ventilation units are made of polymer corrugated pipes.

Restriction on the use of portable ventilation units: the presence of dust and particulate matter in the air does not exceed 100 milligrams per 1 cubic meter of air. Temperature up to +80 degrees Celsius. Lack of aggressive impurities.

Portable ventilation units are widely used in manufacturing and construction (for example, during welding in an enclosed space).

Telescopic ventilation units

Telescopic ventilation units are designed for ventilation of granaries.

The sections are connected to a powerful fan. To make it easier to move the unit around the ventilated room, the telescopic tube is installed on a slide.

The installation stretches across the floor and is connected to the fan before loading the grain. As necessary, the fan is turned on and the grain is blown through.

As a rule, a telescopic ventilation unit consists of 5 links, which are inserted into each other.

When it is necessary to pull out the telescopic tube, it is first disconnected from the fan, then pulled out by the tractor using the cable provided for this.

Average characteristics:

• productivity is about 20 thousand cubic meters per hour;
• the length of one section of the telescopic tube is 2 m;
• unit weight without fan 170 kg.

Dust collecting ventilation units

The dust-collecting ventilation unit is designed to filter the air from shavings, metal dust and other inclusions that appear during the operation of grinding, sharpening and cutting machines.

Dust collectors are used for ventilation of glass, metalworking, woodworking industries.

The dust extraction unit blows air through bag filters and a dry cyclone, eliminating 99.9% of existing impurities. They are collected in a special compartment at the bottom of the device. Such an installation has a capacity of 2 thousand cubic meters of air per hour and can only service one machine.

Compact ventilation units

These are small monoblock devices designed to ventilate one room. The most famous representatives of supply ventilation units: "Sphere", "Marta", "Aeropack", "Tion". Unfortunately, the Sfera ventilation unit has been temporarily out of production.

Ventilation units for inflow "Marta" and others can be used in living rooms and offices. They work non-stop.

Other characteristics of dust extraction ventilation units:

• productivity of about 120 cubic meters of air per hour;
• noise up to 40 decibels;
• power 40 W / h - 1 kW / h;
• three speeds of air supply;
• air filtration;
• air heater with a capacity of 0.8 - 1 kW / h.

The principle of operation of the supply ventilation unit "Marta"

The body is mounted on the inside of the house. Through the air intake pipe, the air is supplied by the fan to the heater, then it is filtered and discharged into the room.

A characteristic feature of the Marta ventilation unit and some others is air recirculation. Thanks to this, the device does not freeze even at very low temperatures.

Features and benefits of air handling units

Ventilation units offered on the market have a lot of advantages:

• Compactness and ease of use. For example, the installation of the ventilation unit "Marta" can be carried out by the owner himself, at a rather modest expense;
• A large selection of ventilation units with recuperators, air conditioners, mobile, type-setting or monoblock allows you to choose the best option for a room of any size and purpose;
• A wide choice of options allows you to save on secondary functions, if necessary;
• Modern installations are quite economical.

Completion of installations

Any ventilation unit, be it "Sphere", "Marta" or industrial with recuperation, consists of the main modules:

1. Fans. They move air into and out of rooms. In household models, axial fans are used, in industrial models they are more often "snails";
2. Air ducts. Through them, air is transported to the desired place. Their walls should be as smooth and tight as possible. Air ducts are made of plastic or sheet metal;
3. Check valve. Installed from the street to the air duct to prevent cold air from blowing in when the equipment is turned off;
4. Automation and security system. A set of sensors and controllers that regulate the operation of the entire ventilation unit with recuperation;
5. Protective grilles and blinds. Cover the air ducts from dust, insects and small animals. The grille is installed on the front of the building, therefore sometimes it also bears a decorative load;
6. Filters, heaters, air conditioners. With the help of these modules, the air acquires the best performance: it is purified, brought to the desired temperature. Air-conditioned ventilation units are in great demand in office buildings.

Air handling unit maintenance

Air handling units with air conditioners, recuperators and filters require periodic inspections, adjustment and cleaning.

Service tasks:

• Inspection of fasteners and the integrity of mechanical parts;
• Density control of air duct connections, filters;
• Visual inspection of the integrity of the fan impeller and dampers;
• Cleaning or replacing filters;
• Air condition monitoring;
• Valve tightness testing;
• Inspection of ventilation duct mountings;
• Checking temperature and humidity sensors;
• Checking the tightness of connections, including inspection of all welds;
• Checking the condition of the wiring, measuring voltage levels on the main modules;
• Testing the operation of coolers and heaters.

Typically, service is carried out once every 6-12 months. But in some types of industries, prevention is needed every 2 months.

Now in more detail about the checks of various units of ventilation units.

Fan

With prolonged or intensive use, the transmission belt from the engine to the fan may wear out. The belt is slack and the engine is idling without driving the fan. The slipping of the shafts also leads to abrasion of the belt. Therefore, they need to be tightened periodically. A complete belt replacement takes approximately half an hour.

In addition, there are bearings in the fan design. They should be replaced from time to time, otherwise the load on the engine increases, it overheats and may fail.

And the main procedure is to clean the fans. A layer of compressed dust accumulates on the blades and grates, which interferes with work.

Air dampers

The damper is installed in the supply system at the air intake. When the ventilation is off, the damper keeps cold outside air out.

The damper may not work well if the electrical wiring is damaged, the device is icy or clogged with fluff, dust.

The condition of the air dampers must be checked at least once a year before the onset of cold weather.

Filters

The air passing through the damper is immediately fed to the filters. In supply ventilation, disposable filter cartridges are usually installed, which must be changed periodically. The filter can last from 2 to 6 months.

Exhaust systems also have filters that purify the air before being discharged outside. They are especially important in industries with the release of dust, shavings, and harmful substances. These filters can be cleaned or also changed depending on their type.

Valves

Valves are installed to control the supply of coolant in the supply system. They need to be checked and adjusted from time to time.

Poor operation of the ventilation valve causes system malfunctions and an unjustified increase in energy consumption.

Pumps

In supply ventilation units, mixing pumps are used. Their function is the constant movement of water through the heater.

A breakdown of the water pump causes serious malfunctions, shutdowns and leaks.

Sensors

A large ventilation unit certainly contains several sensors that control the operation of actuators (dampers, fans, pumps, and others).

Adequacy of control of all ventilation depends on the sensors.

They transmit to the controller data on the parameters of the air environment, the operation of various mechanisms and assemblies.

The sensors are tested once every 6 months in late autumn and early spring.

Heat exchangers

Dust accumulates on the heat exchangers, which reduces heat transfer, which means the efficiency of ventilation. The condition of the heat exchanger depends on the cleanliness of the filters. So, with their timely washing or replacement, the heat exchanger will have to be cleaned only once every few years.

One of the best technologies for cleaning heat exchangers is soft blasting:

If the air handling unit is not equipped with an automatic control system such as Marta, the owner can carry out the inspection and cleaning himself. Complex installations with branched air ducts are serviced only by specialists. The service cost depends on the capacity and type of installation.