The invention concerns a safety arrangement for a double valve in particular for transportable containers of the type serving to distribute a liquid under pressure from a gas, said arrangement comprising a housing for detachable mounting the valve in a vertically placed neck ring in the container, and a riser pipe mounted displaceable in the housing acted on by a pressure spring, said riser pipe having an elastomere valve ring having both a blockable gas passage between the housing and the valve ring and a blockable liquid passage between the opening of this latter and a valve plug in the riser pipe being loaded from a second pressure spring, the arrangement also comprising a catch placed in the housing under the neck ring and having a vertically downwards converging wedge, the narrow edge of which is tiltingly supported at the bottom of a window in the wall of the housing.
Liquids such as beer and Coca-Cola are to a very great extent distributed in transportable containers under pressure of gaseous CO.sub.2. During dismounting the pressure can shoot the valve out into the room with great force, whereby a person, when being hit by the valve, can be seriously injured.
In the European Patent Application NO. 0 489 829 a solution to this problem has been described. A catch is placed under the neck ring in a window of the housing of the double valve, said catch can be tilted around a lower edge in the window between an outwards tilted blocking position and an inwards tilted free position. At the bottom of the catch is also an inwardly turning projection. The catch is kept in an outwardly tilted position by means of a resilient finger placed on the riser pipe. In this position the valve must not be able to be dismounted by persons who do not have a special tool adapted for the purpose.
A special tool such belonging to the valve is in principle similar to the coupling head which is being coupled on to the double valve in order to dispense the liquid content from the container. The special tool, however, has a longer spindle and consequently, when being activated by the handle of the coupling, it pushes the riser pipe a little further down into the valve housing than is normally the case. The overpressure in the container is in this process rapidly blown off via the specially adapted coupling head. The valve can now be dismounted without any risk and this has now been possible due to the fact that the riser pipe, when being displaced downwardly at the same time, has brought the finger so far down that its lower end has been able to tilt the catch into the free position by stepping on its inwardly turning projection.
The construction known from the European Patent eliminates in an expedient manner the risk that an unauthorized person, who tries to dismount a pressure loaded valve, will be injured. Since the special tool, however, is a normal coupling head with prolonged spindle, the valve can nevertheless be dismounted by an unauthorized person by means of a normal coupling head, if the person in question realizes that he can put a disc between the spindle and the valve ring at the upper end of the riser pipe. The construction is furthermore rather complicated and the long finger can, by manipulating the riser pipe, disengage the catch which thereby is put out of function.