Dosing unit, a dosing method, and a machine for producing unit dose articles
A dosing unit for a machine for producing unit dose articles includes a plurality of nozzles carried by respective movable elements and associated to fluid delivery lines, and a plurality of controlled valves associated to respective actuators and arranged for selectively opening and closing a passage of fluid through said fluid delivery lines.
1. A dosing unit for a machine for producing unit dose articles, comprising:
a stationary guide defining a closed-loop guide path having a lower section and an upper section,
a plurality of movable elements movable along said stationary guide,
a transmission system configured for continuously moving said plurality of movable elements along said closed-loop guide path,
a plurality of nozzles carried by respective movable elements and connected to fluid delivery lines,
a rotary fluid distributor comprising at least one stationary inlet connected to at least one pump and a plurality of movable outlets connected to respective fluid delivery lines,
a plurality of controlled valves associated to respective actuators and arranged for selectively opening and closing a passage of fluid through said fluid delivery lines, and
a control unit configured for controlling an open/closed state of said plurality of controlled valves through said actuators.
2. The dosing unit of claim 1 , wherein said control unit is configured for controlling a volume of fluid delivered by said plurality of nozzles by controlling an opening time of said plurality of controlled valves.
3. The dosing unit of claim 1 , wherein said control unit is configured for controlling a volume of fluid delivered by said plurality of nozzles by controlling a pressure of the fluid delivered by said at least one pump.
4. The dosing unit of claim 1 , wherein at least one of said fluid delivery lines is associated to a flowmeter arranged for measuring a volume of fluid delivered through the respective fluid delivery line during each opening cycle of the respective controlled valve, wherein the control unit is configured for receiving, from said at least one flowmeter, data on the volume of fluid delivered by the plurality of nozzles, and wherein the control unit is configured to adjust an opening time of the controlled valves and/or a feed pressure of said at least one pump depending on the data provided by said flowmeter.
5. The dosing unit of claim 1 , comprising a temperature control system configured for controlling a temperature of the delivered fluid.
6. The dosing unit of claim 1 , wherein the plurality of controlled valves includes a plurality of stop valves, wherein each of said plurality of nozzles is connected to a respective fluid delivery line through a respective stop valve of the plurality of stop valves, and wherein said stop valve is opened to allow the fluid to flow from the respective dosing chamber to the respective nozzle when a fluid pressure in the delivery line is greater than a predetermined threshold, and is closed when the fluid pressure in the delivery line is lower than said predetermined threshold.
7. The dosing unit of claim 6 , wherein said at least one pump is configured to deliver fluid at a pressure greater than said predetermined threshold.
8. The dosing unit of claim 1 , wherein said closed-loop guide path has a straight horizontal lower section, a straight horizontal upper section, and two arcuate sections each connecting to each other respective ends of the straight horizontal lower section and straight horizontal upper section.
9. A machine for producing unit dose articles, comprising:
a movable surface having a plurality of cavities, continuously movable in a machine direction,
a first feeding assembly configured for feeding a first continuous water-soluble film on said movable surface at a first position,
a retaining system configured for retaining said first continuous water-soluble film adherent to said cavities as it moves in said machine direction,
a dosing unit located downstream of said first position and configured for dispensing dosed quantities of at least one fluid composition into said cavities,
a second feeding assembly configured for feeding a second continuous water-soluble film on said movable surface at a second position located downstream of said dosing unit so as to enclose said dosed quantities of at least one fluid composition between said first and second continuous water-soluble films, and
a wetting unit configured for wetting a surface of said second continuous water-soluble film upstream of said second position,
wherein said dosing unit comprises:
a stationary guide defining a closed-loop guide path having a lower section and an upper section,
a plurality of movable elements movable along said stationary guide,
a transmission system configured for continuously moving said plurality of movable elements along said closed-loop guide path,
a plurality of nozzles carried by respective movable elements and connected to fluid delivery lines,
a rotary fluid distributor comprising at least one stationary inlet connected to at least one pump and a plurality of movable outlets connected to respective fluid delivery lines,
a plurality of controlled valves associated to respective actuators and arranged for selectively opening and closing a passage of fluid through said fluid delivery lines, and
a control unit configured for controlling an open/closed state of said plurality of controlled valves through said actuators.
10. A method for dosing fluid products, comprising:
continuously moving a plurality of movable elements along a closed-loop guide path having a lower section and an upper section,
providing on said plurality of movable elements a plurality of nozzles associated to fluid delivery lines,
feeding at least one fluid composition to said fluid delivery lines through a rotary fluid distributor comprising at least one stationary inlet and a plurality of movable outlets connected to respective fluid delivery lines, and
selectively opening and closing a passage of fluid through said fluid delivery lines by a plurality of controlled valves associated to respective actuators.
11. The method of claim 10 , comprising controlling a volume of fluid delivered by said plurality of nozzles by controlling an opening time of said plurality of controlled valves.
12. The method of claim 10 , comprising controlling a volume of fluid delivered by said plurality of nozzles by controlling a pressure of the fluid delivered by at least one pump connected to said at least one stationary inlet.
13. The method of claim 10 , comprising measuring a volume of fluid delivered through at least one fluid delivery line during each opening cycle of the respective controlled valve, and adjusting an opening time of the plurality of controlled valves and/or a feed pressure of at least one pump connected to said at least one stationary inlet depending on the measured volume of fluid delivered.
14. The method of claim 10 , comprising controlling a temperature of the delivered fluid.
15. The method of claim 10 , comprising stopping a flow of fluid directed from said fluid delivery lines to said plurality of nozzles when a pressure of the fluid is below a predetermined threshold.