Beverage preparation machine with manually operated pump with flow control means

A beverage preparation machine for providing a pressurized liquid to a dose of beverage ingredients, the beverage preparation machine comprising:

• a pressurizing liquid chamber configured for being filled with liquid upon operation of a liquid pump connected to a liquid reservoir of the beverage preparation machine;
• a potential energy accumulator associated with the pressurizing liquid chamber, the potential energy accumulator configured to move between a charged position and a non-charged position, wherein the potential energy accumulator is configured to move into the charged position upon filling of the pressurizing liquid chamber;
• a brewing chamber configured for receiving the dose of beverage ingredients, the brewing chamber configured for being brought into fluid communication with the pressurizing liquid chamber;
• a flow control configured for regulating the liquid conveyed from the liquid pump into the pressurizing liquid chamber according to at least two flow control modes depending on the charged position or the non-charged position of the potential energy accumulator;
• and
• the at least two flow control modes comprise a first flow control mode in which the liquid is conveyed from the liquid pump into the pressurizing liquid chamber when the potential energy accumulator is in the non-charged position and a second flow control mode in which the liquid is conveyed from the liquid pump back into the liquid reservoir when the potential energy accumulator is in the charged position;
• wherein the flow control comprises a first valve and a second valve arranged in a fluid path between the liquid reservoir and the pressurizing liquid chamber, the first valve being positioned between the liquid pump and the liquid reservoir, the second valve being positioned between the first valve and the pressurizing liquid chamber, and wherein the second valve is a check valve;
• and
• wherein the flow control comprises a third valve positioned to bypass the first valve by fluidly connecting a conduit downstream the first valve to a conduit upstream the first valve, wherein the second valve is configured to open while the first valve and the third valve are closed when the pressurized liquid chamber is filled, the third valve configured to direct the liquid back to the liquid reservoir when:
• a pressure between the liquid pump and the pressurizing liquid chamber exceeds a predetermined threshold;
• or
• the potential energy accumulator is in the charged position.