Anordning vid blandningsanordningar för blandning av pulverformiga och vätskeformiga ämnen med varandra för framställning av medicinska produkter

摘要

The present invention relates to a device at mixing devices for mixing pulverulent and liquid substances with each other for the manufacture of medical products, wherein a displaceable piston means (17) has at least one groove (22) extending around said piston means (17) and at least one sealing ring (23) is located in said groove (22). At least one connecting passage (22e) is provided for preventing a liquid substance (21) from generating or building up such a pressure in an inner space (22d) in the groove (22) within or behind the sealing ring (23) that said pressure presses the sealing ring (23) in a direction outwards (F) relative to the groove (22) towards a surrounding wall (1a) of the mixing device (1) and prevents or counteracts flow of the liquid substance (21) past the piston means (17) when said piston means (17) is displaced.