The device (1) has a connector comprising an opener for opening a gas cartridge, where the cartridge is connected by the connector to a channel in a pressure-tight manner, and the device is made of plastic material, such that gas from the cartridge flows along the channel. The channel connects the connector to surroundings of the device, where the channel comprises one T-piece with a vacuum connector (12) for a vacuum cementing device. The T-piece forms a Venturi nozzle, such that the gas from the cartridge flowing through the channel generates negative pressure at the vacuum connector. The device includes an operable blocking element made of metal. The operable blocking element comprises one valve selected from rotary valve, ball valve, pinch valve, pin valve or slider. An independent claim is also included for a method for generating a negative pressure in a vacuum cementing system.
