A pressure therapy device (100)includes a pressure chamber (110),an inflatable padding(140),a seal (150),and a positioningmechanism (172). The pressure chamber (110)has an opening(120)arranged for admittingthe inflatable padding(140)and a limbof a user. The inflatable padding(140)is inflatable in order to enclose and fix the limb in position. The seal (150)covers the opening (120),including the inflatable padding(140)and the limbin order to seal the pressure chamber (140)from ambient atmospheric pressure. A pump unit (190)is provided to generate a non-atmospheric pressure within the pressure chamber (110),and includes a first valve system (210)and a piston (200)with safetyrelease features for preventingunsafe pressure levels.
