According to the different structures of the dust cleaning devices, it can be divided into four categories: tubular injection pulse dust collector, box injection pulse dust collector, mobile injection pulse dust collector, and rotary injection pulse bag dust collector
(1) Tubular Injection Pulse Dust Collector When the pulse dust collector is cleaning the dust, the compressed air is directly injected into the filter bags through the holes of the injection pipe above the mouth of the filter bags. Some are equipped with a Venturi tube at the mouth of the filter bags for flow guiding, and some are not. However, it is required that the holes of the injection pipe and the center of the filter bags are on the same vertical line. Tubular injection (as shown in Figure 3-67) is one of the most commonly used dust cleaning methods. Its characteristic is that it is easy to achieve uniform injection of all filter bags, and the dust cleaning effect of the filter bags is good. (2) Box Injection Pulse Dust Collector In box injection, one pulse valve is used for dust injection in one bag chamber, and there is no injection pipe. One dust collector is divided into several bag chambers, and several pulse valves matching the bags are installed. As shown in Figure 3-68. The biggest advantage of box injection is that the injection device is simple, and it is convenient to replace the bags and carry out maintenance. However, the number of filter bags in a single chamber is limited. If the number of filter bags is too large, it will affect the dust cleaning effect of the filter bags.
(3) Mobile Injection Pulse Dust Collector A mobile injection head is composed of one pulse valve, one movable pipe, and several nozzles. Each group of filter bags is correspondingly equipped with a separated gas collection chamber. When the injection head moves to a certain gas collection chamber, the pulse valve is opened, and the high pressure is sprayed into the box through the nozzles, and then enters each filter bag for dust cleaning, as shown in Figure 3-69. Its characteristic is that one set of injection device is used to inject several rows of filter bags. Although mobile injection can reduce the number of injection pipes, it has strict requirements for the processing and installation accuracy of the injection pipes, and the maintenance is not convenient. (4) Rotary Injection Pulse Bag Dust Collector A large rotating main pipe is used for pulse injection of the filter bags (usually flat bags). Its structure is similar to that of the rotary reverse air blowing bag dust collector. The differences are as follows:
① Pulse valves are used for intermittent dust cleaning;
② A gas distribution box is provided;
③ The dust cleaning is carried out with the air stop of the divided chambers. The structure of the upper box of the dust collector is shown in Figure 3-70.
