39 - Which processes are important for material conveying?
The principle of suction conveying relies on the vacuum pump generating a vacuum that is great enough to range through the material feed lines and the material loaders to the material feed.
Depending on the conveying controls and the material loader model, either so-called time or sensor conveying is possible. For sensor conveying, the material loader must be equipped with a fill level sensor.
The processes of both variations are comparable: a sensor in the material loader signals the material requirements to the controls. After this the vacuum pump starts running and conveying begins.
For sensor conveying the material loader is supplied with material until the fill level sensor signals that the machine is full. It then sends an impulse, which stops conveying of material. For time conveying, the system supplies the material loader with material for the duration of a pre-set conveying time.
If emptying or purging of the lines has been set, this will occur after conveying. Here it is important to bear in mind that any material remaining in the material feed lines will also be conveyed into the material loader. This is particularly important for longer conveying distances. Thus, the times and position of the fill level sensor must be set so that the total material conveyed does not overfill the material loader.
Sensor conveying is often combined with additional time conveying. Here, the maximum fill level of the material loader is both timed and controlled by a sensor. If the material level does not reach the fill level sensor in the set time, an error message occurs. A benefit of this monitoring method is that it also recognises if enough material is being conveyed.
On the other hand, the simple and more indirect method – for material loaders with outlet flap – only monitors whether material is delivered or not.
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