Features of the machine for ventilating the greenhouse

Such a structure as a greenhouse should fully provide acceptable conditions for the crops growing in it. The environment in which plants grow and develop in greenhouses has a number of specific features that relate to the provision of care, watering, microclimate, ventilation and others. Since their ability to bear fruit depends on the combination of these factors, it is very important to choose the right device for automatic ventilation of the greenhouse.

The main requirement for such structures is the presence of a constant flow of fresh air, which will allow the plants to create an optimal level of humidity and temperature. Gardeners and summer residents are regularly faced with the task of arranging a system or installation that will work in the room as a ventilator, since the air flow is responsible for the possibility of pollination during flowering. Today, the acquisition and installation of automatic devices for air ventilation will help to effectively solve this issue.

The airing machines have characteristic technical and operational features:

• size - the maximum length of the thermal drive is 45 cm, the minimum is 33 cm;
• the device can withstand a wind load of up to 100 kg;
• to ensure productive work, the stem in the device must be treated with engine oil every year;
• the temperature at which the device can function smoothly varies from +60 to -40C;
• the vents open at a temperature of + 24C;
• close at 22C.

The use of systems for ventilation of greenhouses has a number of positive properties:

• the possibility of self-ventilation, no need for the presence of a person;
• easy installation of the device;
• affordable cost of production;
• lack of dependence on the supply of electricity in the case of the installation of autonomous greenhouse ventilation systems.

Automatic machines for ventilation of greenhouses, presented by modern domestic and foreign manufacturers, include a lot of different models.

According to the fundamental criterion that concerns the way devices function, they can be classified as follows:

• group of autonomous systems;
• volatile models.

The principle of operation unites these devices - a thermal actuator acts as the basis for ensuring productive work. In order to perform their tasks, electrical mechanisms must be provided with a power source. It can be an electric current or a solar battery. The operation of the electric drive is controlled by a thermostat, where the required temperature is set, allowing crops to develop correctly in the greenhouse.

Device models that need to be powered by electricity have some drawbacks due to the nature of their mechanical device.

• the high cost of devices associated with the need for the tightness of the internal components, since they contain electronics;
• the uselessness of devices as a result of a power outage at the site or a complete blackout of the room. However, the purchase of a backup electrical unit will help to avoid situations associated with a power failure and the operation of the device;
• when one component of the system becomes unusable, repair or replacement of the entire unit may be required.

In addition to the disadvantages of electrical systems, a number of advantages of mechanisms can also be distinguished:

• high power devices;
• fulfillment of the task in the shortest possible time;
• compactness of devices;
• high-tech products.

Autonomous mechanisms are subdivided into several groups.

Based on the device system, they are:

• hydraulic devices;
• pneumatic devices;
• bimetallic ventilation mechanisms.

The functioning of the units is carried out through the use of a hydraulic drive and a thermal drive, which work due to the properties of various substances to expand under the influence of temperature. In the thermal relay, specific parameters are set, based on which the operation of the device takes place. They can be simple or complex, computer controlled.

For the assembly of bimetallic devices, two metal strips are usedhaving a different coefficient of expansion. They are connected to each other along the entire length, and under thermal action (heating of raw materials), one product lengthens and bends. Due to its impressive length, the metal strip provides a good force, sufficient to open the window. When the room temperature drops, the plate cools down and regains its original dimensions, due to which the sash closes.

The disadvantage of such a ventilator is the difficulty of selecting the correct temperature level for ventilation in the room.

Hydraulic mechanisms perform ventilation by expanding the fluid in the hydraulic cylinder due to thermal effects. As the oil heats up, it increases in volume, thereby pushing out the piston, which is fixed with the window. This phenomenon ensures the opening of the transom and the ventilation of the greenhouse. As the air cools, the fluid cools and the piston is retracted, thereby returning the flap to the closed position.

The disadvantages of such a device include a certain inertness of the liquid - it changes its temperature and volume rather slowly, which entails an untimely reaction to a decrease in the overall temperature in the room. It is best to purchase such devices for installation in greenhouses, where transoms are located at the top, for example, in domed buildings. In these structures, heated air is collected directly near the vents, and a too cooled flow does not reach the plants quickly, so it cannot harm them. Such devices identify the temperature indicator only in their immediate vicinity.

The high cost of the device is also a disadvantage.

The advantages of airing with hydraulic devices include the following nuances:

• the ability to work in comfortable conditions;
• lack of unpleasant odors;
• independence from energy sources;
• easy assembly without the involvement of specialists;
• there is no need to always be near the facility to control the climatic conditions.

If you opt for hydraulic automation for ventilation of greenhouses, then it is worth considering the following important factors:

• devices in this category will need to be installed on each transom in the room;
• before purchasing this or that device, it is worth familiarizing yourself with the power of lifting the window, which is provided by the proposed device;
• preliminary designate the maximum weight limit that the entire greenhouse structure can withstand.

Pneumatic devices have some advantages:

• autonomy from any power supply;
• low cost;
• high performance indicator.

The disadvantages include the following features:

• impressive dimensions;
• small working effort;
• the power level is directly related to the pressure in the atmosphere.

The operation of such types of devices for ventilation of greenhouses has its own nuances:

• it is necessary to take into account that the manufacturer sets certain restrictions on the opening angle of the transom with the help of mechanisms, taking into account its weight;
• hydraulic devices must not be installed in areas of the room where they will be exposed to direct sunlight. Since the device will react to the temperature that contact with the sun will provide it, and will not - to the internal temperature in the greenhouse. This will entail an illiterate regulation of the microclimate, as a result of which the cultures growing in the structure may die.

The technology of installing equipment for ventilation of greenhouses is not a complex and highly specialized process.

Installation work consists of several mandatory and sequential stages:

• first of all, you need to perform a number of preparatory work, which includes a preliminary inspection of the vents for their easy and unhindered opening. After making sure that the window structures are in good working order, you can proceed to the next step;
• at the top of the structure, the operation of which will be regulated by the mechanism, it is necessary to correctly determine and designate the place where the bracket will be located;
• the fastening element is fixed to the sash with self-tapping screws;
• the second bracket can be attached to the wall or window frame, also using self-tapping screws;
• then the thermal actuator is fixed to the spring, which ensures the shutter of the transom.

Based on the majority of reviews from the owners of greenhouse facilities, the most popular and effective automatic ventilator is the Dusya-San universal unit. It functions perfectly in any type of construction. The device works on the principle of a gas shock absorber. The sensor is calibrated in a temperature range of + 16-25C, based on the optimal recommended temperature for the productive development of most greenhouse crops. Heating provides thermal expansion of the material, as a result of which the length of the device can increase up to 12 cm.

Technical conditions for the functioning of the apparatus "Dusya-San":

• the sash opening is 45 cm;
• the temperature at which the piston extends to a maximum is 30C;
• 12 months warranty;
• the weight of the structure to be pulled out should not exceed 7 kg.

Ufopar-M has the following technical characteristics:

• light weight of 1.3 kg;
• maximum force on the piston - 100 kg;
• maximum heating - + 80C;
• the warranty period is 5 years.

Univent is an automatic ventilation device. It starts its work when the temperature inside rises to 17 -26C. The maximum opening occurs at the moment when the thermometer records a value of + 30C. The device easily opens the doors, which have a weight of 10 to 40 kg. The device is made with a reinforced metal case and a special system that allows the device to be used as a door ventilator for greenhouses.

To create the right conditions for the maturation of plants in the greenhouse, you can use several types of automatic ventilation of the room.

• provide ventilation by arranging two transoms located next to each other. Buildings with a large area are equipped according to this principle without fail;
• through ventilation - carried out when the doors are automatically opened. Experts recommend this option for narrow structures;
• a mechanism built into the wall, which will ensure the opening of the vents;
• device with sensors for monitoring temperature and humidity inside. Such a device can be made by hand.

Experienced gardeners do not advise arranging opening structures for ventilation near the front door.This advice avoids the formation of drafts, which have a detrimental effect on developing crops, especially young shoots. And also such an arrangement can lead to a sharp slamming of the vents during auto-ventilation by gusts of strong wind, as a result of which the device, which is installed on the sashes or doors for ventilation, will become unusable. The ideal location for the vents would be the middle of the structure.

For an overview of the thermal drive for ventilating the greenhouse, see the video below.