IMPORTANT INFORMATION
MAIN TYPES OF GREENHOUSE
1. INTRODUCTION.
A greenhouse is any enclosed structure covered with transparent material within which it is possible to obtain artificial microclimate conditions, and thus grow plants outside station in good condition.
The advantages of using greenhouses are: 1 .- Earliness
in fruits.
2 .- To increase the quality and performance. 3 .- Production
outdated.
4 .- Water saving and fertilizer.
5 .- Improving insect and disease control.
6 .- Ability to obtain more than one crop cycle a year.
Disadvantages:
7.-High initial investment.
8.-High cost of operation. 9.-
requires expertise, practical experience and theoretical knowledge.
greenhouses can be classified in different ways. As
attend certain characteristics of building elements (for external profile as their fixation or mobility, roofing material, according to the material of the structure, etc.).
The choice of a greenhouse is a function of a number of factors or technical aspects:
soil type.
should choose well-drained soils and high quality but with modern fertigation systems can be used poor soils with good drainage and artificial substrates.
a) Topography. Are preferable places small slope oriented north to south.
b) Winds. Be taken into account the direction, intensity and wind speed dominant.
c) bioclimatic requirements of the species in cultivation
d) Climatic characteristics of the zone or area where the greenhouse will be built
e) Availability of labor (human factor)
f) local economic imperatives (market and marketing .)
According to the structural, greenhouses can
Sort of:
Drawings or vine type. Type
amagado scratchcard. Asymmetric
.
Chapel (two waters to a water)
chapel
Type Double or semi-cylindrical tunnel. Glass or
Venlo.
2. GREENHOUSE PLAN OR TYPE PARRAL.
Such gases are used in areas with little precipitation, although it is undesirable for construction. The structure of these gases are composed of two distinct parts, a vertical and horizontal structure:
vertical structure.
is made up of rigid media can be differentiated depending perimeter (fence brackets and bands located in the corner) or inside (right foot).
intermediate Studs are usually separated about 2 m in longitudinal and transverse direction 4m, while separations are also 2x2 and 3x4.
perimeter supports are inclined outward approximately 30 ° from the vertical and with the winds that hold the upper end cordate serve to tighten the wire cover. These supports generally have a separation of 2 m, although in some cases are used distance of 1.5 m.
Both external and internal supports may be pine or eucalyptus logs and galvanized steel pipes.
The horizontal structure is formed by two overlapping galvanized wire mesh, manually implemented simultaneously with the construction of the greenhouse and used to carry and hold the plastic sheet.
greenhouses have a flat deck height varies between 2.15 and 3.5 m height of the bands between 2 and 2.7 m. The supports of the greenhouse is supported by prefabricated concrete blocks placed truncated on small caissons.
The main advantages of the greenhouse plans include construction
's economy.
Its great adaptability to the terrain. Mayor
wind resistance. Take
rain water in dry periods.
presents a very uniform light. The disadvantage of
are
little volume of air.
stuffiness. Installation of windows
zenith is quite difficult.
Too much specialization in construction and maintenance. Rapid aging
installation. Little or nothing
advisable in wet places. Risk of caving
bags rainwater that form in the plastic sheet.
Risk of destruction of plastic and installation by their vulnerability to wind. Hard
difficulty in mechanization and tillage by the excessive number of poles, wire winds, anchor stones, etc.
tight little drip of rainwater and air as it is necessary to make holes in the plastic to the union of the two wire mesh, which favors the proliferation of fungal diseases.
3. GASES IN RASPA and Amager.
Its structure is very similar to the type vine but varies the shape of the deck. It increases the maximum height of the greenhouse at the ridge, which ranges between 3 and 4.2 m, forming what is known as scraping. In the lower part, known as amagado, join the mesh cover to the ground by winds and iron forks allows you to put the gutters for drainage of rainwater. Amagado height ranges from 2 to 2.8 m, the bands between 2 and 2.5 m.
The separation between the supports and the winds of Amager is 2x4 and the angle of the deck between 6 and 20 º, the latter being the optimum value. The recommended orientation is east-west. Advantages
scrape greenhouses and amagado:
• - The economy.
•-unit volume has increased and therefore higher thermal inertia night temperature increases with respect to greenhouse levels.
• - has good sealing to rain and wind, thus reducing indoor humidity during periods of rain.
• - presents a greater surface free of obstacles.
• - Allows overhead ventilation system located downwind, along the edge of the ridge.
Disadvantages:
• "Differences in brightness between the south and the north side of the greenhouse.
• - does not take advantage of rainwater.
• - change is hard plastic cover.
• "By having more developed area will increase heat loss through the roof.
4. ASYMMETRICAL GREENHOUSE OR INACRAL.
differs from the type amagado scraped and the increased area on the exposed face south to increase its capacity to capture solar radiation. For this, the greenhouse is oriented east-west, parallel to the sun's apparent path.
The slope of the roof should be one that allows solar radiation impinges perpendicularly on the deck at midday during the winter solstice, a time when the sun reaches its lowest point. This angle should be close to 60 º but it causes great inconvenience by the instability of the structure to high winds. For this angle taken between 8 and 11 on the south side and between 18 and 30 on the north side.
The maximum height of the ridge varies between 3 and 5 m and a height of 2.3 to 3 m. The height of the bands between 2.15 and 3 m. The separation of domestic support is usually 2x4 m. Advantages
asymmetrical greenhouses:
• - Good use of light in winter.
• - The economy.
• - High thermal inertia due to its unit volume.
.- It is waterproof to rain and wind.
• - Good ventilation due to its high altitude.
• - Allows ventilation system overhead downwind. Disadvantages
asymmetrical greenhouses:
• - No advantage of the rainwater.
• - It is difficult to change a plastic cover.
• - has more heat loss through the roof due to the largest developed area compared to the flat type.
5. CHAPEL GREENHOUSE.
simple chapel greenhouses have roof forming one or two inclined planes, as a water or two waters.
This type of greenhouse is commonly used, highlighting the following Benefits: • Easy
construction and easy maintenance.
• It is acceptable for placement of all types of plastic on the cover.
• Ventilation vertical walls is very easy and can make large areas with simple mechanization. It is also easier to install windows zenith.
• It has great facilities for draining rainwater.
• To join several ships on drums.
The width is usually given to these greenhouses is 12 to 16 meters. The ridge height is between 3.25 and 4 meters.
If the inclination of the planes of the roof is more 25 ° do not provide problems in the evacuation of rainwater.
Ventilation is by front and side windows. When it comes to structures formed by several ships joined the zenith makes no windows for ventilation.
6. CHAPEL GREENHOUSE DOUBLE
double chapel greenhouses consist of two ships side by side. Ventilation is better than in other types of emissions, because they have overhead ventilation system on the top of the two steps that form the juxtaposition of the two ships, these vents typically remain open constantly and they usually get in mosquito netting. In addition they also have ventilation vertical front and side walls.
This type of greenhouse is not widespread because their construction is more difficult and expensive than the type of greenhouse simple chapel gable.
7. GREENHOUSE TUNNEL OR Half-cylinders.
form is characterized by its cover and all-metal structure. The use of such gases is spreading its best to control the climate, its resistance to strong winds and speed of installation to be prefabricated structures.
brackets are galvanized iron pipes have an inner separation 5x8 or 3x5 m. The maximum height of this type of greenhouse between 3.5 and 5 m. Sidebands are taken heights from 2.5 to 4 m.
The width of these ships is between 6 and 9 permit my townhouse several ships on drums. The zenithal ventilation through windows that open onto the outside of the greenhouse. Advantages
tunnel greenhouses:
• Structures with few obstacles in its structure.
• Good ventilation. • Good sealing
to rain and wind.
• Allows ventilation system overhead downwind and facilitates machining operation.
• Good distribution of light inside the greenhouse.
• Easy installation.
Disadvantages:
• High cost.
• It uses water from rain.
8.INVERNADEROS GLASS OR Venlo.
This type of greenhouse, also called Venlo, is a prefabricated metal structure covered with glass and are generally used in Northern Europe.
The roof of the industrial gases consists of glass panels resting on the channels for rainwater collection and a set of crossbars. The width of each module is 3.2 m. From the canals to the ridge there is a single pane of glass with a length of 1.65 m and width varying from 0.75 m to 1.6 m.
The separation between columns in the direction parallel to the channel is 3m. In the transverse direction is 3.2 m apart if there is a line of columns under each channel, or 6.4 m if constructed a lattice-type beam.
Advantages: • Good sealing
allowing for a better climate control in greenhouses.
Disadvantages:
• The abundance of structural elements means less light transmission. • The high cost
. • Ships
very small due to the complexity of its structure.
9. MATERIALS USED IN STRUCTURES.
The structure is the frame of the greenhouse, consisting of studs, joists, rafters, belts, etc.., Which support the cover, wind, rain, snow, equipment installed, overloads staking plants, irrigation and water spray, etc. Should be kept to a minimum shading and freedom of internal movement.
greenhouse structures must meet the following conditions:
• They must be lightweight and strong.
• From cheap and easy material conservation.
• Susceptible to be extended.
• small area they occupy.
• Adaptable and modifiable to cover materials.
The greenhouse structure is one of the structures that best be studied from the point of view the strength and economy, when defined by a particular type of greenhouse.
The materials used in construction of the greenhouse structures are wood, iron, aluminum, galvanized wire and concrete.
is difficult to find a structure type that uses only one kind of material because it is common to use different materials.
structures in greenhouses that are built now combine the following materials: wood and wire, wood, iron and wire, iron and wood, iron, wire and wood, concrete and wood, concrete and iron, concrete, iron , wire and wood. The
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