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Greenhouses are designed to create the right microclimate for growing plants, regardless of the weather. This microclimate includes an appropriate temperature and humidity regime that is optimal for specific crops. Temperature control is carried out with the help of heating and ventilation, so there are always opening windows in greenhouses. But the owner cannot open or close them all the time, it is better to organize automatic control of the windows, it is quite possible to do it yourself.
Types of ventilation systems
Industrial greenhouses are usually equipped with special ventilation systems, and small greenhouses in suburban areas replace them with simple ventilation. If in summer the access of fresh air to greenhouses is almost constant, then the colder it is outside, the more strictly it is necessary to monitor the opening of the windows and the air temperature in the greenhouse. For this purpose, special machines have been created.
In accordance with the technology used, they are of three types:
- electrical;
- hydraulic;
- bimetallic.
The easiest to install and operate electric automatic devices for opening window leaves. They consist of a temperature sensor and an electric motor. As soon as the temperature rises to the indicated level, the sensor activates the engine, which sets the window in motion. When the temperature drops to the desired level, the reverse process occurs. The only disadvantage of such a device is the requirement for constant power supply, not all greenhouses are provided with it.
Devices based on hydraulic technology are reliable and very simple. Containers filled with liquids respond to an increase in temperature by increasing pressure (when the liquid expands), the hydraulic mechanism is activated and the window opens. As the temperature drops, the pressure drops and the vent closes. Summer residents often make such machines with their own hands. The disadvantage is the slow response – when the temperature drops, the window leaf slowly returns to its place, there is a risk of plants freezing.
The bimetallic lever works by lifting the window, because different metals expand at different temperatures, and its action is based on this. The only bad thing is that such machines are designed for light weight, they cannot cope with a glazed transom.
Installation
If the summer resident purchases a factory device that will automatically open the windows in the greenhouse, then it will not be difficult to install it with your own hands, strictly adhering to the attached instructions. But there are points that are not indicated in the instructions. For example, even at the stage of building a greenhouse, you need to consider the location of transoms and doors – they are not made on the same wall. Window vents do not need to be located on the side from which a strong wind usually blows, it is generally better to arrange them from above.
Light electric machines can be mounted directly on the window, and heavier ones are mounted on the frame elements of greenhouses, it would be nice to know the weight of the device in advance, check the options for its placement. The vents must be equipped with special tapes (ropes, chains), which will not allow them to open too much, but will fix a certain opening angle.
All such devices depend on temperature, you need to know that it is the air temperature in the greenhouse that is measured, and not the heating of the device itself – you may need to hide the machine from direct sunlight.
Video “Window vents for the greenhouse”
Air vents are designed for ventilation of polycarbonate greenhouses. The vent frame is made of galvanized steel and is assembled with screws and nuts.
Homemade designs
With an eye on the prices of factory-made automatic devices, very often summer residents assemble them with their own hands literally from improvised means. To make a hydraulic device that opens and closes the windows in the greenhouse at a certain temperature, you will need 2 cans, 3 liters and 1 liters, connected by a hose.
The leaf of a window leaf is fixed in a frame on the rotating axis. A small can is suspended from the upper part, and the lower one is balanced by a bar. A large jar is suspended from the ceiling. We poured 1 liter of water into it, sealed it tightly (you can just roll it up with a metal lid). A hose was inserted into the lid (it should not reach 0,5-1 cm to the bottom) and connected to a small jar (it could just be a rubber or PVC hose, or maybe a copper tube inside such a hose). That’s the whole device, it works great, although it looks very simple. When the temperature rises, water from a large jar will flow into a small one, and with its weight, it will open the window.
Many do not use glass jars, but plastic bottles (5 l + 1,5 l), it’s even easier to do it yourself. Design options are possible – each owner invents something of his own, but the general principle is still the same.
Homemade design:
- counterweight;
- sash;
- retainer;
- fastening.
Factory production
Factory devices based on hydraulics are also made according to the same scheme. The hydraulic cylinder can be of different volumes (it determines how heavy the window it will lift), inside it is oil (paraffin), and not water, as in home-made devices. The movable rod is fixed at one end of the structure. The base is fixed on the vertical stand of the greenhouse or window frame. The rod is attached to the window frame, when it is extended, it opens. If the device does not provide hurricane protection, you need to make safety chains or tapes that will not allow the window to open more than necessary.
Such a device works in the same way as what they do with their own hands: when the air temperature rises, the oil (or paraffin) expands, the pressure increases, the rod moves and opens the window. Gradually, the temperature drops, the oil reduces the pressure, and the rod returns to its original position, closing the window.
For those gardeners who do not risk making such devices with their own hands, there are many offers on the market. The most common devices can cost from 1500 to 2000 rubles, these are Dusya-Sun, UFOPAR, Tuymazy. If you are willing to shell out more, then you should pay attention to the Danish Gigavent and Megavent machines, the English Autovent XL and Autovent MK7.
You choose some factory device or make an automatic machine yourself, it will greatly facilitate the process of growing vegetables in a greenhouse.
Video “Installation of automatic machine for ventilation of greenhouses “Dusya – Sun”
Automatic opening of the greenhouse window without electricity using “Dusya – Sun”
