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US 7,287,964 B2Granted
Method and system for pumping powder, and powder coating apparatus
AssigneeITW Gema AG
InventorMarco Sanwald
Life of this patent
Estimating the term…
Abstract
In a pump system for supplying powder, in particular coating powder, to a powder coating apparatus, time controller is used to introduce compressed gas into a metering chamber as a function of the predetermined delay time elapsed since a predetermined operational point for the purpose of expelling a quantity of powder that was introduced into the metering chamber until the end of the time delay.
Claims26
A pumping system for coating powders, comprising at least one powder pump comprising:
- a metering chamber which is bounded by a chamber housing;
- and
- an expelling element which is forward-displaceable relative to the chamber housing during a pressure stroke and backward during a suction stroke;
- the metering chamber comprising:
- a powder intake duct associated with a power intake valve,
- a powder outlet duct associated with a powder outlet valve, and
- a compressed gas intake duct associated with a compressed gas intake valve,
- the powder intake valve being opened to aspirate a metered quantity of powder into the metering chamber while the powder outlet valve and the compressed gas intake valve being closed, whereby a movement of the expelling element in the direction of the suction stroke aspirates powder through the powder intake duct into the metering chamber, and
- the powder intake valve being closed in order to convey the metered quantity of powder out of the metering chamber while the powder outlet valve and the compressed gas intake duct are opened, as a result of which compressed gas flowing from the compressed gas intake duct is able to force the metered quantity of powder from the metering chamber into the powder outlet duct;
- said pump system further comprising a pump control unit to drive the compressed gas intake valve;
- wherein
- the pump control unit comprises a time controller by means of which a predetermined delay time is counted since a predetermined operational point, the compressed gas being introduced at the end of the delay time into the metering chamber and the quantity of powdered metered until the end of the delay time is forced by the compressed gas out of the metering chamber.
9 more elements
A method of conveying coating powder, said method comprising the steps of:
- aspirating powder, by increasing the volume of a metering chamber, from a power source onto said metering chamber;
- after said aspirating, expelling the metered quantity of powder, by means of compressed gas, out of the metering chamber, thereupon the volume of the metering chamber being decreased and the cycle of said aspirating and expelling steps being periodically repeated,
- wherein
- during said aspirating, a predetermined phase of the periodic change in volume of the metering chamber is detected;
- and
- said expelling is initiated with a predetermined delay time after the predetermined phase has been reached, whereby the quantity of powder metered up to that time is forced out of the metering chamber by means of the compressed gas.
3 more elements
A method of conveying coating powder, said method comprising the steps of:
- aspirating powder by enlarging the volume of at least one metering chamber from a powder source into the metering chamber;
- and
- after said aspirating, expelling the metered quantity of powder out of the metering chamber by compressed air, the volume of the metering chamber then being decreased and the cycle of said aspirating and expelling steps will be repeated periodically,
- wherein
- the volume changes of the at least one metering chamber are controlled by a predetermined cycle time,
- following lapse of the predetermined cycle time, at least one control signal is generated to reverse the direction of volume change from enlarging to decreasing or vice versa and, simultaneously, a predetermined delay time is initiated, and
- only when the predetermined delay time has lapsed shall the metered quantity of powder be forced by the component gas out of the metering chamber.
4 more elements
Dependencies are inferred from the claim text.