Apparatus for mixing vaporized precursor and gas and method therefor

An apparatus for mixing a vaporized precursor with a gas for producing silica particles, said apparatus comprising:

• a mixer housing;
• a precursor delivery chamber having an output in communication with the mixer housing for delivering a vaporized precursor in the mixer housing;
• an oxidizing gas delivery chamber having an output in communication with the mixer housing for delivering an oxidizing gas to be mixed with the vaporized precursor;
• a flashback member disposed within the mixer housing and between the output of the precursor delivery chamber and the output of the oxidizing gas delivery chamber, wherein the flashback member is located at a minimum distance from the output of the oxidizing gas delivery chamber defined by Lminimum (cm)=0.453U (Re)−0.5567, wherein U is the flow rate in cm/sec of precursor and Re is the flow Reynolds number.

An apparatus for mixing a vaporized precursor with a gas for producing silica particles, said apparatus comprising:

• a mixer housing;
• a precursor delivery chamber having an output in communication with the mixer housing for delivering a vaporized precursor;
• an oxidizing gas delivery chamber having an output in communication with the mixer housing for delivering an oxidizing gas to be mixed with the vaporized precursor;
• a flashback member disposed within the mixer housing and between the output of the precursor delivery chamber and the output of the oxidizing gas delivery chamber, wherein the flashback member comprises a tapered surface on at least one side to reduce recirculation of vaporized gas.