Winter pig farm construction: teach you how to design the air inlet of the pig house
Reasonable selection, layout and control of air inlets are very important and are the key to achieving good airflow distribution, which can effectively avoid many ventilation problems. There are many different types of air inlets available on the market. Today, RICHI will come to discuss the common types and layout of air inlets in pig houses.
Currently, the four-opening and two-opening small air inlet windows without driving and the single and double opening air inlet windows with driving are commonly used in China. The air inlet can be arranged according to the size and shape of the pig house. The layout and management of the air intake in winter should aim at letting the intake air flow as far as possible and covering all areas of the pig house. How far the inlet airflow blows is actually related to many factors such as the fresh air temperature, the temperature in the house, the size and type of the air inlet, and the distance between the air outlet and the ceiling, etc. The calculation is relatively complicated.
For example, installing a heating fin tube under the air inlet can effectively increase the range. In order to facilitate the application of a simple algorithm provided by some American experts, for every increase of 2.5Pa in the static pressure difference, the airflow can blow 0.6m more. Therefore, if the system is operating at a static pressure difference of 10Pa and the inlet wind speed is 4m/s, the airflow will blow 2.4m. At the static pressure difference of 15Pa and 25Pa, it is expected to blow 3.6m and 6m respectively.
For example, a row of small windows with driving two openings in the middle aisle of a 12.5m wide pig house must reach a static pressure difference of 20Pa to allow airflow to blow to the side walls and cover all pigs And help form a defecation area near the wall. If the system is operating at a static pressure difference of 10 Pa, the fresh air may fall into the pig activity area in the upper part of the fence. This will cause ventilation problems.
So when considering the air inlet layout, we need to know the static pressure difference that this type of air inlet can achieve during operation to determine the spacing between the air inlets. There is no driving four-open air inlet window, because there is no driving adjustment, no counterweight, it is difficult to form a large static pressure difference when the ventilation volume is small. When we arrange this kind of air inlet, we can only cover an area of 6m×6m according to each air inlet.
A small window with two driving openings can be used to effectively adjust the size of the air inlet opening, which can achieve a large static pressure difference. The arrangement of this type of air inlet can cover an area of 12m×8.5m according to each air inlet. . In addition, in order to maintain effective airflow distribution, do not hang anything that will affect the airflow on the ceiling or near the ceiling. If the wire ducts, material lines and water ducts block the airflow, the airflow will sink rapidly, forming a thief, and preventing the air from mixing fully. There should be no obstructions within 2m of the airflow path. Try to use a smooth ceiling board, which can increase the distance of the air flow forward and cover a larger area.
Of course, in addition to the small air inlet windows mentioned above, there are other special types of air inlets, such as porous diffuse ceilings, fabric ventilation ducts, perforated ventilation ducts, etc. They also have their own scope of application and precautions.
Take the diffuse ceiling as an example. The fresh air enters the corridor from outside the house (the heater can be used for preheating in the corridor), and then enters the attic through the upper opening of the corridor. The entire space of the attic acts as a static pressure box to form the attic The air pressure is stable and the wind speed is very small. Fresh air enters the house slowly through the porous dispersive ceiling covering the entire pig house, and then exits the house through the chimney fan from under the trench. The characteristic of this kind of airflow distribution is that pollutants can be pressed to the lower part, the air quality is good, and the temperature field and wind speed field in the pig house are also uniform and stable. This kind of airflow distribution is very suitable for cold areas in the north, especially suitable for nursery houses and farrowing houses with higher thermal comfort requirements.
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