Thawing tube guide for a culvert

DETAILED DESCRIPTION The present invention is a culvert thawing tube guide which is positioned at the opening of a culvert to enable a maintenance worker to easily introduce a thawing tube with a rat into an ice-covered culvert.
The main component of the culvert thawing tube guide is a guide pipe.
The guide pipe has a discharge end disposed within the culvert opening and an inlet end disposed in a predetermined position for safe access by a maintenance worker.
The guide pipe does not extend along the entire length of the culvert.
Rather, the discharge end of the guide pipe need only extend into the culvert far enough to guide the rat into the culvert opening.
Thus, the length of piping needed is minimized.
The interior passage of the guide pipe is of a predetermined diameter which is large enough to permit a rat to enter the inlet end, pass through the entire length, and exit the discharge end of the guide pipe.
As standard a thawing tubes' rat has a diameter of approximately 1", and the optimal size for the interior diameter of the guide pipe is 3" to 4".
Preferably, the guide pipe should not contain any angles greater than 45.
degree.
to ensure that the rat does not get caught up in the guide pipe.
Alternatively, in those applications where the culvert opening is located at the bottom of a deep, narrow access hole, the guide pipe may be bent in a curve having a radius sufficiently large to permit passage of the rat.
Another option entails utilizing a guide pipe with an enlarged diameter.
The enlarged diameter would provide enough space in the guide pipe passage to allow a rat to maneuver through a 90.
degree.
pipe angle.
The guide pipe may be constructed of any of a variety of conventional piping materials, such as iron, galvanized or stainless steel, or high-pressure plastic tubing.
However, the material chosen for the guide pipe must be able to withstand the high-pressure steam which is discharged from the rat as the thawing tube is passed through.
Preferably, the guide pipe should be capable of withstanding a steam pressure of at least 200 psig