The fan is installed on the side wall of the chicken house; the longitudinal fan is installed at the end of the chicken house.
With the arrival of winter, the main ventilation mode of the chicken house environment will also be the minimum ventilation mode. One of the key factors for the successful operation of the minimum ventilation system is to select a reasonable minimum fan unit.
At present, people in the industry generally agree with two views:
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One is to choose the horizontal fan unit
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The second is to choose the vertical fan unit·
And no matter what kind of point of view people hold, it seems that they have experienced a lot of empirical evidence and have achieved successful cases. People on both sides are not giving in to each other, and they are full of confidence in their own views.
Should the farming site choose a horizontal fan unit or a vertical fan unit?
First of all, from the perspective of classical ventilation theory, minimum ventilation is horizontal ventilation.
Advantages of cross ventilation in winter:
It can discharge the exhaust gas in the house in the shortest time and with the fastest efficiency
The air index in the house is more uniform
The temperature difference between the front and back of the house is smaller
Minimum wind speed through the chicken body
However, horizontal ventilation has higher requirements on the airtightness and heat preservation of the chicken house. Otherwise, a large amount of cold wind will enter the front and rear end areas, which will inevitably lead to cold stress and even disease in the chicken flock.
Let's look at the disadvantages of choosing longitudinal fans for the smallest fan unit:
It will inevitably cause a temperature difference between the front and back, and the temperature of the probe at the back will always be higher than that of the probe at the front. If there is no or very small (adult chickens), please check whether the position and height of the temperature probe in the chicken house are appropriate.
The chicken house will form a certain longitudinal wind speed, which will have a certain degree of impact on the chickens in the cold winter, especially the young chickens
The air quality at the rear of the house will also always be worse than at the front, as the tunnel fans will continue to pull the exhaust air from the front to the rear.
When the negative pressure is small, the air intake of the small window at the rear end is greater than that at the front end.
That being said, here comes the problem!
Why there are so many disadvantages in choosing longitudinal fans for minimum ventilation, and many chicken houses in China still make such decisions?
There are probably four reasons:
01
The horizontal fan was not designed at the beginning of the chicken house building design.
Frankly speaking, most domestic poultry farming enterprises, especially individual companies, are relatively weak in technical strength. The construction and design of chicken houses have basically not undergone strict technical design and evaluation of equipment parameters. They are built entirely based on the boss's own subjective consciousness. , or imitate the structure of other players and completely copy it.
What's more, equipment manufacturers have not fully fulfilled their due obligations. In order to achieve cooperation, they failed to persist in persuading customers to adopt reasonable design concepts, and often made compromises with customers. What's more, equipment suppliers themselves There are also no professional technicians to help customers design a reasonable chicken house, which ultimately leads to the fact that there is no horizontal fan at the source of the design of the chicken house.
02
The horizontal fan is useless, and I dare not use it. Once it is used for chickens, it is easy to cause problems, so it is simply discarded.
There are quite a lot of breeding sites for this phenomenon. What is the reason?
In order to save costs, the building structure of the chicken house is relatively poor in material selection, resulting in poor airtightness of the chicken house. The exhaust gas in the house is discharged at a faster rate when the horizontal fan is used, which will cause the temperature of the chicken house to be low, especially at the front and rear ends, and even cold. Stress-induced illness, etc.
Henhouses with good conditions were built. After the transition to winter, they did not pay attention to the airtight heat preservation of the henhouses, especially the longitudinal fans at the rear end, the manure passages in the cages, etc., which were not effectively airtight. Lead to the above phenomenon, resulting in the disease of chickens.
Although the selection of longitudinal fans will reduce the effective power of the fans, it will also compensate for the low temperature phenomenon at the rear end caused by air leakage from the fan or manure duct, because the heat from the front end will always be drawn to the rear end, thereby reducing the risk of disease in the chicken flock.
03
In a well-ventilated environment, the risk of using longitudinal fans to the flock has not yet reached the level of flock health imbalance.
The chicken flock can still maintain good production performance, and the on-site managers are worried that there will be problems, so they simply maintain the original status.
04
Relatively controllable reduction of biosafety cross-risk.
The exhaust direction of the horizontal fan is always the air intake area of the adjacent chicken house. If the chickens have aerosol-type infectious diseases, the transmission speed of the horizontal ventilation will be faster. This is one of the main reasons why many companies choose the vertical fan .
According to the survey and survey, it is roughly calculated that horizontal fans are commonly used in China, most of which are group companies and a few individual enterprises. There are two things in common.
One is that the design of the chicken house is relatively standard, and the construction materials are relatively high-quality, and the other is that the daily basic management work is relatively rigorous.
The above two points can effectively avoid the stress on the chicken house environment caused by poor airtightness, as the so-called good steel is used wisely.
In summary:
Classical ventilation theory guides us that transverse fans should be selected for the smallest fan unit. But please remember a premise, which is to ensure that the chicken house is airtight and well-insulated, otherwise it will be counterproductive. When the condition of the chicken house is poor, it is also the best choice to choose the longitudinal fan as the smallest fan unit. Now you should understand which type of fan should be used as the minimum ventilation fan unit for your chicken coop!
