Spirax-Sarco valve mechanism less bucket is the device that allows the condensate and air to drain from the trap. The mechanism is a lever and seat operation, it is held in place by screwing the seat into the outlet port within the trap. With the inverted bucket attached to this mechanism, the steam pressure within the bucket keeps the lever up in turn keeping the seat closed when steam is present. When the steam cools and turns to a liquid state (condensate), the trap fills with condensate causing the bucket to drop and this opens the seat to allow the condensate and air to drain.