An
elbow fitting for use in a pneumatic product conveying
system expands from the inlet
pipe along the outer side of the
elbow fitting and contracts along the outer side of the fitting toward the outlet
pipe for guiding product particles into the outlet
pipe. The expanded structure of the
elbow fitting defines a generally triangularly shaped configuration that provides a wide surface over which an accumulated layer of product particles moves at a
lower velocity than the velocity of the incoming product
stream. The accumulation layer of product forms a moving contact surface for deflecting incoming product particles toward the outlet pipe with a minimum of
pressure resistance and product attrition. The configuration of the expanded elbow fitting provides a slowly moving layer of accumulated product particles due to the law of gravity and Bernoulli's Law.