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Freeze Resistant Nozzle Disclosure Number: IPCOM000006110D
Publication Date: 2001-Dec-04
Document File: 6 page(s) / 1M

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US 2,797,946: PATENT


A freeze-resistant nozzle for use in a traction system including an inlet end for receiving traction material and a discharge end for evacuating the traction material. A discharge orifice is provided in at the discharge end and directs the traction material to a wheel-rail contact region. A flange is attached to the discharge end adjacent the discharge orifice for diverting water away from the discharge orifice.

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This application claims the benefit of U.S. provisional patent application 60/124,547 filed March 15, 1999, the entire contents of which are incorporated herein by reference.


The invention relates to a freeze-resistant nozzle for use with an on-board traction system which provides adequate traction between the wheels of a locomotive and the track upon which it travels.  An on-board traction system is used on locomotives to blow a mixture of air and traction material (e.g. sand) into the wheel-rail contact region to improve adhesion to the rail.  A nozzle is used to direct the traction material at the wheel-contact region.  Fig. 1 is a side view of a conventional locomotive sand nozzle.  The discharge end 2 of the nozzle is an oval cylinder 10 that is rigidly attached to a transition piece 8.  The transition piece 8 is oval at its point of attachment to the oval cylinder 10 and is circular cylindrical at its opposing end where it rigidly attaches to a circular cylindrical structure 6.  The distal end of the circular cylindrical structure 6 is the inlet end 4 of the nozzle.

Traction material (e.g. sand) is an important friction-enhancement agent in the locomotive traction system.  During winter operation, when sand is arguably needed the most, it is not uncommon for locomotive sand nozzles to freeze at the discharge end 2 and thereby block the flow of sand.

It is understood that the mechanism by which a locomotive sand nozzle freezes is a cumulative cold weather phenomenon whereby water is whipped onto the nozzle by the combined action of the proximity of the locomotive wheel and by water running down the surface of the nozzle and collecting at the discharge end 2.  The surface tension of the water causes the water to “turn the corner” at the discharge end of the downwardly angled nozzle toward the interior of the nozzle.

It is further understood that the latent sand dust inside the nozzle then “wicks” moisture up into the nozzle by means of capillary action.

Even in low ambient temperatures, water running down the nozzle may be warmed enough by the locomotive wheels braking so as to flow in sufficient amounts to thereby create a potential freezing problem.   In cold ambient conditions, this mechanism causes a gradual, but complete, blockage of the nozzle.  Fig. 2 shows an enlarged view of the discharge end 2 of the oval cylinder 10.  The aforesaid “wicking phenomenon” is represented by the flow representation A.  Fig. 3 shows the end view of the discharge end 2 of the nozzle.  The oval envelope 16 of the discharge end 2 and the oval nature of an inner bore 18 are shown.

An exemplary embodiment of the present invention is a freeze-resistant nozzle for use in a traction system.  The freeze-resistant nozzle includes an inlet end for receiving traction material and a discharge end for evacuating the traction  material.  A discharge orifice is provided in at the discharge en...