Disposable pump for dispensing small metered amounts of liquid from a container and a control unit for operating said pump

A disposable pump for dispensing small metered amounts of liquid from a container having only one mouth opening with adjacent connecting means for the pump,

• said pump comprising a housing and a cylindrical piston,
• said housing having a first bore, closed at one end, for slidably and rotatably accomodating the piston, a second bore disposed perpendicularly with respect to the first bore, connecting means for co-operating with those of the container being arranged adjacent the outer end of the second bore,
• said first bore comprising a narrow inward section and a coaxial wider section,
• said narrow section communicating through a supply conduit with the second bore and through a dispensing conduit with a dispensing orifice opening outside the housing,
• the wider section communicating near its upward end portion through a gas inlet conduit with the second bore,
• said piston comprising a thinner inward section, closely fitting in the narrow section and provided with at least one groove at least partly extending longitudinally with respect to the piston up to the inward end thereof and being arranged such as to prevent simultaneous communication with both the supply conduit and the dispensing conduit,
• said piston having a coaxial cylindrical sealing lip elastically bearing against the inner surface of the wider section of the first bore,
• said piston also having coupling means for connection with a control unit for transmitting both longitudinal and rotational movement to the piston.