Patent ID: 7056360

Claim:
A method of odorizing natural gas flowing through a pipeline by injecting odorant into the pipeline at a controlled rate, the method comprising the steps of: providing an odorant storage tank containing an odorant to be injected; communicating a pressurized source of inert gas with the odorant storage tank for maintaining the tank at a desired positive pressure above the pressure of the pipeline; providing an injection conduit communicating the odorant storage tank with the pipeline; providing metering means located within the injection conduit for metering odorant to be injected into the pipeline on a dropwise basis with the individual drops of odorant being counted as they pass through the metering means into the injection conduit and into the natural gas pipeline; wherein the metering means includes a servo driven flow control valve which controls the flow of odorant through an orifice; and wherein the metering means includes counting means for counting individual drops of odorant passing through the orifice into the injection conduit, the counting means including a photooptic light source and mating sensor.