As the name suggests, this is a flat sifter. The sieve is in a perfectly horizontal position within a frame that supports it and the particles to be classified lie on it.
This is the most accurate form of sifting, and that is why laboratory sifters use the same principle.
In contrast to laboratory sifters, Plansifters have sieve cleaning elements called tapotines. They move in such a way that they keep the perforations of the sieve surface free of particles that get stuck in the perforations of the sieve surface. In general, wire or nylon fabrics are used as sieves.
There are different types of screens that are best suited to each type of material or sieve perforation. Of these, the most common is the following one made of cotton.
Other types of tapotines:
To facilitate the flow of the screened product into the outer channels, “Extractors” like the one in the picture are fitted.
Construction materials: The original sieves were 100% wood. They are currently manufactured in the following alternatives:
- General construction in wood lined with plastic laminate to reduce wear and tear. They can also be made with wooden or aluminium looms.
- General construction in synthetic material. In this case, the looms are always made of aluminium.
Bottomless sieve shaker made of food-grade synthetic material with telerin or aluminium frame.
Construction details that guarantee the correct fittings over time
Plansifter types: We can classify them into 2, depending on whether the external product discharge channels are inside the screen construction or not.
High-capacity PC plansichter:
The outer channel is made of metal and the screens are fitted inside it. Each one has up to 10 sections or piles of screens. They are made up of three structures: two sieve-screener bodies and a control body.
Monocanal BPM plansifter:
It has the outer channels incorporated in the sieve. We only manufacture it in the 1-section version.
The machine is supplied in the BPM(a) version, for suspension mounting with vertical rods, and the BPM(b), which is constructed with mounting feet with ROSTA® anti-vibration elements, which, unlike the old machines with rubber bushings, ensure perfect suspension with little maintenance.