The pipes bends and elbows are essential to give the pneumatic conveying system flexibility through the routes to be taken, but they cause certain problems which must be taken into account at the design stage. Each bend makes a contribution to the overall resistance of the system and therefore to the air pressure required. The abrupt change of direction given by an elbow causes problems with friable substances and can generate angelic hair with synthetics.
From our company you can purchase bends and elbows in different materials and shapes, designed to minimize the mentioned problems. Among the materials we have bends and elbows in steel, cast iron, alloys, basalt, rubber, alumina and other materials. In terms of shape, conventional bends have a constant bore and radius, and others have been developed with specific characteristics for pneumatic conveying.
For conveying abrasive substances, we sell the blind T-arm elbow, which is so effective that it can even be constructed from waste materials. The blind T-arm traps a small amount of the transported substance, so that the new substance arriving from the pipe collides with it instead that with the elbow, which is therefore protected. On the other hand, there is an increase in the pressure drop and some time must be spent periodically cleaning the blind arm.
A more advanced version of the blind T-arm is the Booth elbow. Here the blind part is slightly curved, so that the substance trapped in it can be easily purged; there is also a threaded plug for intervention in the event of a blockage.
Another version, which is even more resistant to erosion and degradation, has a spheroidal chamber in the blind arm. The trapped substance remains in constant swirling motion, providing a cushioning effect for the incoming substance.
The expanded bend elbow, on the other hand, is designed to protect both the pipe and the material. Both of these issues are significantly affected by velocity. With the expansion of a large part of the elbow the air velocity is reduced, as is the speed and impact of the substance against the pipe wall. The turbulence in the bend is so intense that even if the air velocity decreases, below the minimum value required, it is highly unlikely that a blockage will occur at the bend.
The range elbow, on the other hand, has been specially designed to minimize the problem of angelic hair formation that occurs with substances such as nylon and polymers when they slide along the inner surface of a conventional pipe.