How to quickly distinguish high from low pressure blower

High-pressure fan generally has high speed, small blade, large blade angle, and the handling air volume is smaller than low-pressure fan (fan blade length is short, fan diameter is small, blade speed is more than 1500 revolutions/minutes close to 45 degrees angle full pressure can reach more than 800Pa). Low-pressure fan generally has low speed, low wind pressure and large handling air volume (fan blade length is longer). The diameter of the fan is large, and the speed of the fan is low about 500 rpm/min 50Par. The low-pressure fan generally has a large air handling capacity, which is suitable for the place where the large volume of air needs to be replaced by silence. 1. High, medium and low pressure fans are distinguished by their specific revolutions (n). n> 60 is low pressure fan; n = 60-30 is medium pressure fan; n = 30-5 is high pressure fan, and the specific revolutions are obtained by calculation. For example, 72 in 4-72-4.5A is the specific speed of this fan model, 72> 60, so we can identify it as a low-pressure fan. 2. With the same motor power and the same speed, different types of fans produce different air volume and total pressure. For example, 4-72-4.5A is a low-pressure fan with a maximum air volume of 10562 m3/h and a total pressure of 2550 Pa; Y5-47-5C is a medium-pressure fan with a maximum air volume of 8909 m3/h and a maximum total pressure of 472 3Pa; 9-19-5A is a high-pressure fan with a maximum air volume of 7488 m3/h and a maximum total pressure of 5697 Pa.