A flow restriction detector for a nozzle assembly

摘要

A flow restriction detector for a nozzle assembly of a liquid dispensing machine is capable of detecting a blocked or partially blocked nozzle during the cleaning of the nozzle assembly. During nozzle cleaning, a return plate is attached to the nozzle plate of the nozzle assembly to receive a flow of pressurized fluid from the nozzles. Both the inlet and return fluid lines are provided with pressure sensors, and the return line has a constant back pressure applied to it so that the differential between the inlet and return line pressure sensors is in the range 5-10 psi. The pressure differential is monitored during cleaning and from one cleaning to the next for the purpose of identifying a blocked or partially blocked nozzle. A change of as little as 5% from the pressure differential value established for an unblocked system may indicate a partial blockage of a nozzle.