Method and device for determining the volume of liquid remaining inside a flexible liquid-dispensing pouch

A process for determining the volume of liquid remaining Vr inside a flexible pouch initially filled with a known volume Vi of a liquid to be consumed and provided with means for dispensing the liquid to be consumed, the process comprising:

• placing the flexible pouch inside a rigid envelope initially filled with a known volume V1 of a first measuring liquid having an electrical conductivity C1;
• during the dispensing of a volume VA of liquid to be consumed, admitting inside the rigid envelope the same volume VA of a second measuring liquid present outside the rigid envelope to compensate for the loss of volume due to the dispensing of the volume VA of liquid to be consumed and to maintain the pressure balance of the assembly, the second measuring liquid having an electrical conductivity C2 different from the electrical conductivity C1 of the first measuring liquid;
• measuring the electrical conductivity CM of the mixture of the first and second measuring liquids present inside the rigid envelope;
• determining the volume VA of liquid to be consumed that has been dispensed from the measurement of electrical conductivity C3;
• and
• calculating the volume Vr of liquid to be consumed remaining inside the pouch from the volumes Vi and VA.

A device for determining the volume of liquid remaining Vr inside a flexible pouch placed inside a rigid envelope, comprising:

• a flexible pouch intended to be filled with a known initial volume Vi of a liquid to be consumed, said flexible pouch being provided with means for dispensing the liquid to be consumed;
• a rigid envelope inside which the flexible pouch is placed and which is intended to be initially filled with a known volume V1 of a first measuring liquid having an electrical conductivity C1;
• means for admitting inside the rigid envelope a volume VA of a second measuring liquid present outside the rigid envelope to compensate for the loss of volume due to the dispensing of the same volume VA of liquid to be consumed and to maintain the pressure balance of the assembly, the second measuring liquid having an electrical conductivity C2 different from the electrical conductivity C1 of the first measuring liquid;
• an electrical conductivity sensor positioned inside the rigid envelope to measure the electrical conductivity CM of the mixture of the first and second measurement liquids present inside the rigid envelope;
• and
• calculation means to determine, from the measurement of the electrical conductivity CM, the volume VA of liquid to be consumed that has been dispensed and, from the volumes Vi and VA, the volume Vr of liquid to be consumed remaining inside the pouch.