Patent ID: 8047228

Claim:
A method of feeding a measured amount of particulate material, the method comprising: (a) providing a first amount of the particulate material in a fluid to form a slurry, and feeding the slurry to a particulate material metering system, wherein the particulate material comprises a catalyst selected from a Ziegler-Natta catalyst, a metallocene catalyst, a single site catalyst, a chrome catalyst, a supported Ziegler Natta catalyst, a supported metallocene catalyst, a supported single site catalyst, a supported chrome catalyst or a combination thereof, the particulate material metering system comprising: (1) a valve body defining a valve chamber, an inlet port and a discharge port, wherein the inlet port and discharge port communicate with the valve chamber; and (2) a substantially spherical valve member in the valve chamber, the valve member comprising a passage having a first frustoconical passage section and a second frustoconical passage section separated by a filter and within said passage and having an inlet surface proximate to the inlet port and a discharge surface proximate to the discharge port, wherein the passage extends through the valve member from the inlet port to the discharge port; (b) retaining the first amount of the particulate material in the first frustoconical passage section and discharging the fluid through the filter through the second frustoconical passage section and the discharge port; (c) repeatedly juxtaposing the valve member to place the second frustoconical passage proximate to and communicating with the inlet port; and (d) providing either (1) a second amount of the particulate material in the fluid to the inlet port and the second frustoconical passage section and retaining the second amount of the particulate material in the second frustoconical passage section on the filter and discharging the fluid through the filter which flushes the first amount of particulate material through the first frustoconical passage section and the discharge port, or (2) a quantity of the fluid to the inlet port and the second frustoconical passage section that discharges through the filter which flushes the particulate material through the first frustoconical passage section and the discharge port; and/or (3) introducing a quantity of fluid through a flush port within the valve body located adjacent to and directed at the discharge surface to allow the introduction of a fluid to the discharge surface of the filter; wherein said valve member is repeatedly juxtaposed at intervals of less than about 10 seconds.