This is a form of separator placed at the top of an outboard exhaust pipe to prevent the water carried up in the steam from falling upon the roofs of buildings or in the street below. Fig. 58 is known as a centrifugal exhaust head. The steam on entering at the bottom is given a whirling or rotary motion by the spiral deflectors and the water is thrown outward by centrifugal force against the sides of the chamber from which it flows into the shallow trough at the base and is carried away through the drip pipe which is brought down and connected with a drain pipe inside the building. The passage of the steam outboard is shown by the arrows. Other forms are used in which the water is separated from the steam by deflectors which change the direction of the currents.