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How to ventilate chicken house effectively in spring? (illustrated and illustrated)

2018-04-25 17:30 Source: unknown
Reasonable and effective ventilation can obviously improve the production performance
In keeping with henhouse At the same time, good ventilation is very important. Broiler The life activity of chicken can't be separated from oxygen. Sufficient oxygen can promote the metabolism of chicken, keep the chicken healthy and improve feed Conversion rate.

Good ventilation can discharge the moisture, ammonia, dust and excess heat in the house, so as to provide sufficient fresh air for chickens. Poor ventilation and high concentration of ammonia will bring serious loss to production.

In production, many breeders only pay attention to temperature and ignore ventilation in the early stage of brooding, which may cause ascites in broilers in the middle and late stage. 2、 Poor ventilation at 3 and 4 weeks of age may increase the incidence of chronic respiratory disease and colibacillosis. In the middle and later period, the demand of oxygen and excretion of broilers are increasing. Therefore, ventilation is the main means to maintain the normal environment in the house.
  
The later management of broiler production should focus on ventilation. Due to the high body weight of broilers in later stage Feed intake If they can not be discharged out of the house in time, the living environment in the house will become worse and worse, which will not only seriously affect the growth rate of broilers, but also increase the mortality of broilers. In the later stage of feeding, the body weight of broiler can increase about 1.4 Liang per day, and one dead chicken will lose about 20 yuan. It is self-evident that good ventilation management is of great importance to improve economic benefits.

Now we are emphasizing the importance of ventilation. How should we ventilate? The following two ventilation methods are introduced to you, hoping to have a useful reference for you.

   Theory 1: minimum ventilation system
The minimum air exchange (winter, brooding period) is to ensure that the oxygen concentration in the chicken house is 19.2%.
   (1) Theory of minimum ventilation system

A) ventilation system with minimum oxygen concentration of 19.2% in chicken house (minimum standard ventilation rate).
Using the exhaust fan which can exchange the air in the chicken house every 8 minutes, the exhaust fan can work for 2 minutes in a 10 minute ventilation cycle. (the air circulation should be at least 1.5 minutes, and the effect of exhaust fan working time less than 1.5 minutes will not be very ideal.) The minimum standard air exchange rate is an important factor to maintain air quality (oxygen concentration 19.2%), and the stability of temperature should be considered at the same time of maintaining air quality. The stability of temperature should not be ignored, which will cause cold in chickens.
The working time of fan can be adjusted according to the change of environment outside the house and the age and weight of chicken.
The ventilation cycle is controlled by constant temperature and timing ventilation.

B) the maximum standard ventilation rate of the minimum ventilation system is to increase the exhaust fan so that the air in the chicken house can be exchanged every 5 minutes or work continuously.
When the temperature in the chicken house is higher than the expected temperature, the exhaust fan works
When the minimum standard is reached to the maximum standard, the pressure in the chamber should be kept constant
> from the minimum to the maximum, the temperature controlled exhaust fan also works
The exhaust fan controlled by constant temperature and timing ventilation is switched to temperature control to make it work continuously
In order to maintain a certain pressure, changing the air inlet area is more effective than increasing the number of fans
C) the minimum ventilation system is the ventilation system in which the minimum standard air change rate and the maximum standard air change rate are used alternately
The ventilation rate can be adjusted flexibly according to the change of external temperature. If the temperature is high in the daytime, the starting time of exhaust fan can be increased, and the starting time can be reduced at night.
  (2) practical application of minimum ventilation system
        
Recommended minimum temperature control system with temperature control. The JL 318 can achieve a good ventilation control effect with a few air changes in the actual environment.
Temperature in chicken house
Control method
Working mode of exhaust fan
Other measures
Above target temperature
Maximum standard of minimum ventilation
When the exhaust fan controlled by constant temperature and timing ventilation is switched to temperature control, a new exhaust fan can also be started to cool down.
Continuous operation
(remove excess heat and moisture to maintain temperature stability)

In summer, other fans can be started according to the need for cooling control to maintain the stable temperature of chicken house.
Within target temperature range
Constant temperature timing ventilation control method
According to the chicken's age, weight and external temperature, the opening and closing time can be flexibly set, such as 2 minutes on, 8 minutes off, or 2 minutes on and 3 minutes off.

Constant temperature and timing ventilation
(regularly turn on and off the exhaust fan within the set temperature range)

The air inlet is strictly to prevent the thief wind from blowing directly to the chicken body.
Below target temperature
No ventilation
When the temperature rises within the target temperature range, continue to ventilate.
Suspension of work
(prevent stress caused by excessive temperature change)
If the air quality is very poor, start the heating equipment or increase the heat supply to reach the target temperature range and continue to ventilate

The length of working time is not determined by the temperature in the house, but by the amount of oxygen required by the chicken by 19.2%. If the temperature in the house is low during ventilation, it is necessary to strengthen the heating capacity to achieve a good state of temperature and air quality.
Calculation of capacity and number of exhaust fans required in ventilation system
For example, a chicken house with a length of 120m, a width of 12m and an average height of 2.55m
  120m×12m×2.55m=3672 m3
Exhaust fan capacity required to exchange air in chicken house every 8 minutes (minimum standard for minimum ventilation system)
3672 m3 △ 8 points = 459 m3 / min
(if the exhaust fan is 15500 m3 / h = 258 m3 / min)
459 m3 / min △ 258 m3 / min = 1.78 sets = > 2 sets
(if the exhaust volume of exhaust fan is 290 m3 / min)
459 m3 / min △ 290 m3 / min = 1.6 sets = > 2 sets
Exhaust fan capacity required to exchange the air in the chicken house every 5 minutes (the highest standard of minimum ventilation system)
3672 m3 △ 5 points = 734.4 m3 / min
(exhaust fan: 258 m3 / min)
734.4 m3 / min △ 258 m3 / min = 2.8 sets = > 3 sets
(exhaust fan exhaust volume 290 m3 / min)
734.4 m3 / min △ 290 m3 / min = 2.5 sets = > 3 sets
Therefore, it is more appropriate to install three exhaust fans. These three fans are controlled by constant temperature and timing ventilation method. When the temperature rises to the upper limit, it will switch to the temperature control method, thus forming an ideal minimum ventilation system.
In the above calculation of minimum ventilation, the exhaust fan only works for 2 minutes every 10 minutes. Therefore, the time required for the replacement of 3672m3 air is as follows:
3672 m3 + 2 sets + (258 m3 / min × 2 min) × 10 min = 35 min 30 s = > 40 min
Note: the constant temperature and timing ventilation method requires the user to flexibly set the opening and closing time based on the minimum standard ventilation, combined with the chicken's age, weight and external temperature. For example, when the external temperature is high, it can be turned on for 3 minutes, off for 2 minutes, or 2.5 minutes for 2.5 minutes. When the outside temperature is low, it can be set as 1.5 minutes on and 3.5 minutes off.

  On the air inlet of the lowest ventilation system

1) it is made of PVC ventilation pipes with a diameter of 7.5cm-15cm. The spacing is one ventilation pipe with a diameter of 1 meter, a thick diameter of 2-3 meters and a length of 2 meters, 3 meters and 4 meters. According to the actual situation of the width of the chicken house, or exchange experience with friends in the forum.
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2) small ventilation windows are common.

   Boundary of minimum ventilation system
When the temperature in the chicken house is higher than the set temperature, the exhaust fan is always started by constant temperature control. When the temperature of the chicken house is within the target temperature range, the maximum standard of the minimum ventilation system can be used for air exchange, or the maximum standard and the minimum standard can be adjusted appropriately.

   Minimum ventilation system for special occasions

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* in the case above, when only the exhaust fan of the chicken room is operated, the cold air in the empty room will enter.
* the ventilation of each side of the room is controlled by constant temperature ventilation.
* no matter what the occasion, it is the most important to ventilate the whole chicken house.

   Theory 2: minimum ventilation control

That is to ensure that the harmful gas in the house does not exceed the standard and can meet the minimum ventilation required by the adequate supply of oxygen in the house. For example, taking 5 minutes as a ventilation cycle, the ventilator can be turned on for ventilation every 5 minutes. The method of minimum ventilation, constant temperature and regular ventilation is the key, which can ensure good ventilation and ensure that the temperature during ventilation is not too low.

There is no contradiction between the minimum ventilation rate control and the minimum ventilation system, and they are all for the purpose of increasing oxygen, reducing harmful gas concentration, achieving more effective ventilation and maximizing chicken production performance. There is no obvious difference in actual operation, but there is a slight difference in the calculation of parameters. No matter which method is adopted, the lowest ventilation standard is taken as reference According to the actual situation of winter temperature, adjust the starting time of exhaust fan flexibly, and the actual ventilation volume may reach several times of the minimum standard,

Minimum ventilation standard: it is generally considered that 0.0155-0.017 cubic meters of fresh air are required per kilogram of body weight per minute

Percentage formula of minimum ventilation control fan opening time (percentage of cycle time): 1
Percentage of opening time = number of chickens x average weight of chickens (kg) x exhaust air volume required by kg weight (0.0155-0.017) / fan exhaust air volume

For example, when the exhaust fan uses two axial fans, the exhaust air volume of each fan is 10000 m3 / h = 167m3 / min, the exhaust fan capacity of 2 fans is 334m3 / min, and the average weight of 5000 chickens is 1.5kg, the ventilation time is calculated as follows:

Percentage of opening time = number of chickens x average weight of chickens (kg) x exhaust air volume per kg body weight (0.017) / fan exhaust volume = 5000x1.5x0.017/334 = 0.38.

38 (percentage of opening time) x 5 minutes (cycle time) = 1.9 minutes, that is to say, the minimum ventilation rate of five minutes is a ventilation cycle, and the opening time can be set as 1.9 minutes and the closing time is 3.1 minutes. If the outside temperature is not very low and the temperature in the house is relatively stable, the air volume can be increased. For example, the opening time is changed to 3.8 minutes, and the closing time is changed to 1.9 minutes. The ventilation volume is doubled, so that better air quality can be obtained.

Note: when the opening time percentage reaches 1.0 or more than 1.0, it means that the air volume of the exhaust fan can not meet the minimum ventilation requirement. To increase the exhaust fan or use the fan to implement the minimum ventilation rate, the above introduction "capacity and number of exhaust fans required in the ventilation system" can also be referred to when calculating the number of exhaust fans used for minimum ventilation control Calculate ". Or according to the following formula:

Number of exhaust fans = number of chickens x maximum average weight of chickens (kg) x required exhaust air volume per kg body weight (0.017) / exhaust air volume of single fan = 5000 (birds) x3.25 (estimated maximum weight) x 0.017/167 M3 (air volume of single fan) = 1.65 ≈ 2, two such fans are required. In practical application, the ventilation rate may be twice of the minimum ventilation rate, so at least three fans are required for air exchange.

Relevant instructions for actual operation:

1. The start-up time of constant temperature and timing ventilation must be flexibly used, and the common goal is to maintain the stable temperature and good air quality of the chicken house. The setting time of the exhaust fan can be calculated by the above method, or try to set the time. Start the test from the short opening time, such as 0.5 minutes on and 9.5 minutes off. If this setting does not have too much impact on the temperature, the air will change If the quality is not ideal, you can increase the opening time and reduce the closing time, such as opening 1.5 minutes, closing 8.5 minutes, and gradually increasing the ventilation volume for testing.

2. Pay attention to the humidity when ventilating. If the humidity is too high, ventilation can be strengthened to keep the humidity below 70%.

3. For the temperature management after the lights are turned off at night, the temperature in the house should be increased by 0.5-1 degree, and the ventilation outlet should be turned down to 2 / 3 of the original vent. Maintain the original ventilation. Or keep the temperature in the house after turning off the light, and turn down the air vent to reach 2 / 3 of the original vent. Reduce the ventilation rate by 1 / 3 (reduce the opening time of the exhaust fan), so that the chickens can sleep comfortably without getting cold.

4. Avoid all cold wind blowing directly on the chicken. According to the need, a single-phase motor speed regulator can be added to the 220 V ventilator to reduce the problem of excessive wind speed in the early stage of brooding.

5. The minimum ventilation of the chicken house is enough to ensure the normal oxygen demand of the chickens. If the ventilation is too large, it is a waste of fuel; secondly, the chance of cold wind blowing on chickens is increased; thirdly, the temperature is difficult to control.

6. When calculating the air volume of exhaust fan, it is necessary to consider that the exhaust air volume generally fails to reach the calibration data, which can be calculated as 80% of the rated air volume.

No matter what kind of temperature control equipment is used in the chicken house, no matter what kind of temperature control equipment is needed, it can be used to control the temperature in the chicken house as soon as possible Often convenient.
[editor in charge: shepherd boy]
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