Abstract: A miniaturized, inexpensive instrument for measuring the mass flow rate of powder, which is capable of directly outputting the mass flow rate of powder and whose characteristics are not influenced by the kind and physical properties of the powder. The instrument can be easily manufactured, installed, operated, maintained, and color change can be easily done. A constant powder feeder, which is constructed based on this instrument and an electrostatic powder coating system utilizing this feeder has a high performance and a high operational efficiency. A measuring gas with a regulated flow rate is turned into a thin-layer of high-speed gas jets by a dispersion means, thereby powder is cross-dispersed and introduced into a measuring tube, the pressure difference generated therein is measured, and a feeding means is subject to feedback control so that the output of the pressure difference coincides with a set value.

Abstract: A color-changing powder supply system for use in powder coating, etc. which can perform the color changing in a shorter time, has a simpler structure, requires less expensive equipment cost and installation/setup cost, and can be operated more easily and surely than prior art systems, and a powder coating system which has a high effective rate of operation by utilizing the powder supply system. The pneumatically fed powder supply system comprises a powder tank, a powder supply apparatus detachably connected to the powder tank, and means for cleaning the powder supply apparatus. The powder coating system employs the pneumatically fed powder supply system.