Powder flow detection

摘要

Apparatus for detecting powder flow along a powder flow path includes a light source and a light detector for detecting light from the light source directed across the powder flow path as powder flows through said powder flow path. A circuit receives the output from the light detector and determines an average or RMS of the signal received by the light detector. The circuit may determine whether there is flow or no flow of powder or whether there is a change in flow rate of powder. Preferably, the apparatus is used in combination with a dense phase powder pump, which causes the powder to flow in pulses from the pump outlet into the powder flow path. More preferably, the light source and detector are enclosed in a housing that is connected between the pump outlet and a powder feed hose which supplies powder to a spray gun or hopper.

主权项

1. An apparatus for detecting pulsed powder flow in a tube, the apparatus comprising:
a powder pump comprising a pump chamber, wherein powder is drawn into said pump chamber by negative pressure applied to said pump chamber and powder is pushed out of said pump chamber to a pump outlet when positive pressure is applied to said pump chamber so that powder will flow in pulses from said pump chamber into a powder flow path during operation of said powder pump, a sensor along the powder flow path, wherein the sensor produces an output signal that is related to a flow characteristic of powder from said pump chamber into said powder flow path, a circuit in electrical communication with the sensor, wherein the circuit receives said output signal and determines, based on said output signal, whether powder is flowing through said powder flow path, and a first valve and a second valve in fluid communication with the powder pump, said first valve controlling flow of powder into said pump chamber and said second valve controlling the flow of powder out of said pump chamber.