Atmospheric burner
Burners designed according to the partial premixed combustion method are called atmospheric burners, and their primary air coefficient is 0<a’<1. According to the difference in gas pressure, it is divided into two types: low pressure injection type and high (medium) pressure injection type. The former is mostly used for civilian burning appliances, while the latter is mostly used for industrial installations.
Structure and form of atmospheric burners
Atmospheric burners are usually composed of two parts: an ejector and a head.
In practical applications, the primary air coefficient a of the atmospheric burner is usually 0.45~0.75. Depending on the working conditions of the combustion chamber, the excess air coefficient a usually varies within the range of 1.3~1.8.
The structure of the ejector
In the ejector, the gas flows out of the nozzle at a certain flow rate under a certain pressure and enters the suction contraction tube. The gas sucks in air by its own energy. The gas and primary air are mixed in the mixing tube of the ejector, and then flow out through the head fire hole for combustion. When the gas pressure is insufficient, pressurized air (such as a blower or compressed air) can also be used to inject the gas to complete premixing before combustion.
The function of the ejector has the following three aspects:
(1) Use high-energy gas to inject low-energy gas and mix the two evenly. In atmospheric burners, gas is usually used to inject air from the atmosphere.
(2) The required residual pressure is formed at the end of the ejector to overcome the resistance loss of the air flow at the burner head, so that the gas-air mixture obtains the necessary speed at the exit of the fire hole to ensure stable operation of the burner.
(3) Deliver a certain amount of gas to ensure the required heat load of the burner
Form of ejector
The function of the head of the burner is to evenly distribute the gas and air mixture to each fire hole, and to ensure stable and complete combustion. To this end, the pressur