Choosing a reliable thermal drive for greenhouses
The desire to protect vegetable beds from bad weather under shelters made of polycarbonate or film, while reducing labor costs, pushes gardeners to use automation equipment. The thermal drive for greenhouses is a new, or rather, a "well-forgotten old" device that allows you to create a favorable microclimate for vegetables in greenhouses.
Purpose of the device
Growing an early harvest in the climate of our country is possible only in greenhouses or greenhouses. Spring weather is extremely unstable - after a gloomy morning, the sun may come out by lunchtime, and the temperature will rise to 30-40 in a matter of minutesaboutFROM.
Plants are doomed to die without airing. A device for automatic ventilation of greenhouses eliminates this nuisance by slightly opening the windows or doors of the building.
Types and principle of operation of the device
Free market conditions: the struggle for the buyer, the desire to increase profits and marketing recommendations, force manufacturers to release more and more new models of devices.
In general, two groups of devices can be distinguished:
- Non-volatile ventilation systems that do not require connection to the mains. The devices are left unattended for a long time. Control will be required during sharp fluctuations in air temperature.
- It is undesirable to install electronic automatic drives for a greenhouse in non-residential summer cottages. A temporary power outage in the village leads to the inoperability of the device, as a result, to the death of plants from the heat on a sunny day or from the cold at night. A significant drawback is the need to have a central control unit in stock, if it fails, the entire system will stop working.
According to the principle of operation, non-volatile devices are divided into pneumatic, hydraulic and bimetallic.
Pneumatic
Structurally, the device consists of a working cylinder filled with air or gas. When the temperature in the greenhouse reaches 23aboutC, the gas in the cylinder expands by extending the stem. The force is transmitted to the transom or window. Full opening occurs at an air temperature of about 30aboutFROM.
A decrease in heating returns the gas to its original state, the window is lowered under its own weight.
Models are configured for different modes of use. Before the start of operation, a performance check is carried out.
Advantage of pneumatic device:
- rapid heating (cooling) of the gas in the working cylinder provides an accurate response to changing conditions;
- low price.
The devices are not without disadvantages:
- low effort does not allow handling heavy structures;
- the considerable dimensions of the productive units increase the load on the supporting structures.
Hydraulic models
The hydraulic thermal actuator for the greenhouse is simple in design, which means it is inexpensive. The principle of operation is similar to pneumatic models, but due to the characteristics of the fluid, hydraulic devices are more powerful.
To control the opening of heavy transoms, the hydraulic drive has a different design, which includes:
- hydraulic tank filled with oil;
- connecting hose;
- working cylinder.
Hydraulic drives for the greenhouse have disadvantages: high inertia (the oil heats up and cools for a long time) and sometimes considerable weight and dimensions.
Bimetallic
The work is based on the ability of various metals to change configuration when temperature conditions change.
Bimetallic devices have long lost their relevance due to the high inertia, difficulties with the selection of metals for thermoplastics. The main disadvantage is the small mass of vents available for opening with bimetallic greenhouse ventilation systems.
Electronic
Electronic systems are precise in operation, react instantly to temperature changes. Modern complexes, in addition to opening transoms, contain fans to remove hot air from the upper space.
Temperature sensors transmit information to the main unit, which in turn controls the operation of the drives. Using a chain or worm gear, the drives move - open or close the transoms.
Apart from being dependent on electricity, the systems are road - they are rarely used in private households.
How to choose a thermal actuator for a greenhouse
You should not rely only on the loud promises of manufacturers and sellers when choosing a ventilation system - you need to focus on several circumstances.
The microclimate in greenhouses and greenhouses is always humid; therefore, it is necessary to choose devices made of corrosion-resistant materials.
The airing principle should depend on the vegetables planted. For tomato high humidity and temperature are unacceptable. The vending machine should start opening openings for ventilation at a temperature lower than for thermophilic cucumbers.
For tomatoes, peppers, greens, eggplants, airing is organized by opening the doors to create a draft - in these cases, they choose door thermal drives for greenhouses, or open openings in vertical walls.
Opening and closing the door when entering the building quickly in cold weather will not work - it is better to make two entrances.
Greenhouses with cucumbers ventilated by opening the transoms in the roof. With this approach, drafts are excluded.
A prerequisite for the choice is the weight of the transom, which must correspond to the capabilities of the ventilation devices.
Installation of a thermal drive for a greenhouse
It is not difficult for the gardener to independently install the device, and a minimum of tools will be required. Needed screwdriver or a drill, and the hardware is usually included.
The procedure for installing a closer for greenhouses:
- Inspect all transoms for ease of opening. Eliminate frame distortions, ensure that there are no obstacles for moving structures. Lubricate the hinges.
- Dismantle the locking devices that resist the working cylinder rod - excessive force will damage the device.
- Place the thermal actuator for the greenhouse in a cool place or a common refrigerator chamber for half an hour or an hour - in this way, the stem will assume a position that corresponds to the closed vents.
- Mark the installation site of the device.
- Drill holes in the greenhouse frame and transom frame.
- Mount the thermal actuator according to the instruction manual.
- After waiting for suitable weather (heating the greenhouse), make sure that the mechanism is working. If necessary, adjust the opening using the thread on the lever.
For accurate operation of the mechanism, preventing overheating of the metal case, it is advisable to protect the mechanisms with a sun shield. In this case, it is triggered by heating the air, and not by sunlight.
Service during operation
At the end of the summer season, it is advisable to dismantle the thermal drive for the greenhouse and store it in a dry and, if possible, heated room.
In any case, the stem must be disconnected from the lever.
When entering the greenhouse, a door equipped with a mechanism must not be opened abruptly - this can lead to breakage.
It is forbidden to "help" the closer when closing the door, it must close on its own.
Before the new season, the steps of the correct installation described in the previous paragraph are completely repeated - you don't just have to re-drill the holes.
Whatever the thermal drive device to the greenhouse, it will help keep the plants from overheating and cooling without the participation of the gardener. Timely maintenance and adjustment measures will make the device work long and trouble-free.