Patent ID: 6477896
Filing Date: 2002-11-12
Classification: G01P

Abstract:
Flow indicator to indicate in each of two rooms separated by a wall of a direction of airflow between the two rooms separated by the wall, the flow indicator including a cylindrical tube that is adapted to be mounted through and sealed in an opening through the wall through which the tube passes between opposite sides of the wall, a smooth-running body disposed inside the tube which body easily moves between the opposite ends of the tube due to a pressure difference caused by airflow between the two rooms, an end stop seal provided adjacent each of the opposite ends of the tube arranged to prevent the body from leaving the tube, and said end stop seals being provided with openings which admit air to pass into the tube and which are so shaped that the body, when it reaches one of the end stop seals, sealingly closes the opening of said one of the end stop seals to prevent airflow through the tube and to thereby provide a visual indication in each of the two rooms of the direction of airflow.