What Is a Vacuum Conveyor?
A vacuum conveyor is a machine that uses a vacuum created by depressurization to convey powdered raw materials by air pressure and flow alone (pneumatic conveying).
The power source is a vacuum generated by a vacuum pump, which suctions the raw materials and transports them in the conveying pipe. Unlike the pneumatic conveying method that uses a blower or compression pump, the inside of the piping is a decompressed space where the pressure is lower than atmospheric pressure. Therefore, even if the piping is damaged, the powder will not scatter.
In addition, since powdery materials can be conveyed simply by connecting pipes, the conveying route can be set without restrictions.
Uses of Vacuum Conveyors
Vacuum conveyor is a pneumatic conveying system that conveys powdery materials according to the route connected by piping, and is used to convey various types of powdery materials.
Examples of specific applications include food processing lines where powdered raw materials and products such as flour and sugar need to be transported. As well, as chemical product lines where powdered plastics are used as raw materials and pharmaceutical manufacturing processes where powdered chemicals are used.
Vacuum conveyors are highly regarded for their ability to transport powdery materials directly from hoppers or tanks to the next process simply by connecting pipes. Consequently, there is no need to transfer the powder to another container, as is the case with bucket or belt conveyors, eliminating the risk of powder dispersal.
Principle of Vacuum Conveyors
The vacuum conveyor consists of a vacuum pump as a power source, a tank or hopper for storing raw materials, an ejector or ten-hand tube for feeding raw materials, piping for transporting raw materials, and a filter for separating raw materials and air.
Powdered material mixed with air by the ejector or jute pipe, is discharged downstream following the air flow. At the outlet, the powder is discharged downward by gravity, while the air passes through the filter and is sucked into the vacuum pump, thus discharging only the powder. Filters are available that use centrifugal force for separation or that blow compressed air from the inside of the filter to prevent clogging.
There are two types of vacuum conveyors: intermittent and continuous.
The intermittent type conveys and discharges raw materials alternately, so raw materials are conveyed intermittently. Since the discharge port is not open during conveying, the capacity of the pump, such as flow rate and static pressure, can be set low for the amount of raw material to be conveyed.
Continuous type products convey and discharge powdery materials continuously. Since this method does not require separate conveying and discharging processes, a large amount of raw material can be conveyed in a short period.