Flutter valve
A flutter valve is a check valve , the other without external drive, only on the basis of pressure differences on the two sides of the valve in the forward direction opens and closes again automatically. It consists of an elastic material whose properties also ensure that the valve closes. The materials must also be so rigid that the valve function is ensured in the event of a pressure difference against the opening direction. Flutter valves are usually made of spring steel or plastic.
Flutter valves are used today in diaphragm-controlled two-stroke engines and compressed air breathing apparatus . A flutter valve can also be used with a hydraulic ram . During the Second World War it was used in the pulse jet engine of the V1 . A current application in the field of aviation is found in the high-flyer Hawker Siddeley Harrier , in which flutter valves are used for control at low flight speeds as long as the aerodynamic control is not yet effective. The valves are located in the aircraft nose, in the tail and at the wing tips.
Flutter valves are used in fire fighting centrifugal pumps by the fire service. Their properties are described in DIN 14381. There they are called "screw-down valve (self-closing)". They then consist of: housing, valve spindle with handwheel, spring-loaded valve disc with seal, pawl and stuffing box. How it works: When the valve is closed, the spindle presses the sealing disc firmly into its seat. Water cannot flow in any direction. If the spindle is turned up to the pawl, the spring continues to push the seal plate into its seat. A water pressure directed in the direction of flow can lift the seal and water can flow through it. With "stop water", when no more water is pumped through the valve, the sealing disc closes again (both by the spring pressure and by the counter pressure of the water). In order to be able to drain the outgoing line against the regular conveying direction, the pawl is unlocked and the spindle is turned up to the stop. As a result, the sealing plate is lifted out of its seat and flow can flow through the flutter valve in both directions.
Individual evidence
- ^ Hugh Merewether: Anatomy of a Jump-jet , in Airplane Monthly, November 2002, p. 70
- ↑ State Fire Brigade School Würzburg, fire extinguishing centrifugal pumps and ventilation systems , as of 2010, page 10, http://www.sfs-w.de/lehrmittel/fzgundgeraetekunde/08_06_2011-07-22.pdf ( page no longer available , search in web archives ) Info : The link was automatically marked as broken. Please check the link according to the instructions and then remove this notice.
