Patent ID: 7869037

Claim:
A particle size distribution measuring device that measures particle size distribution of a particle group, comprising: a device body comprising a light source that irradiates light on the particle group and a light detector that detects intensity of diffracted light or scattered light generated by irradiation of the light, a spray measuring system that introduces a sprayed particle group as being the particle group sprayed from a nozzle into a measuring area between the light source and the light detector, and an ordinary measuring system that arranges a measuring cell that accommodates an ordinary particle group as being a particle group other than the sprayed particle group between the light source and the light detector are arranged to be exchangeable for each other; wherein the spray measuring system comprises: a casing that is mounted on the device body and inside of which a measuring area to measure the sprayed particle group is provided; an introducing port that is arranged on the casing and that introduces the sprayed particle group into inside of the casing; and an optical window that is arranged on the casing and between the measuring area and the light source, and between the measuring area and the light detector, and the spray measuring system is mounted on the device body by mounting the casing on the device body in a state that the ordinary measuring system is dismounted from the device body.