Patent ID: 8187476

Claim:
A column assembly comprising: a) a column device, the column device comprising: 1) a column, the column comprising an inner diameter and an upper opening; 2) a lower end, the lower end comprising an effluent port; b) a rigid porous filter placed within the column device, the rigid porous filter comprising a filter diameter no greater than or equal to the inner diameter of the column and a filter height greater than half the inner column diameter; c) a grinding agent or pulverizing agent placed above the rigid porous filter; and d) a volume control device for regulating the volume of fluid delivered to the column assembly, wherein the volume control device is placed within the upper opening of the column device and above the grinding agent or pulverizing agent, the volume control device comprising: 1) an outer column; 2) a base attached below the outer column, the base comprising a hole, wherein the hole in the base impedes or prevents the flow of fluid due to surface tension effects under normal gravity, but permits the flow of fluid through the hole under higher gravitational or other forces; 3) a hollow inner cylinder attached to the base and situated within the outer cylindrical column, the inner cylinder comprising a height and inner diameter; 4) a first cavity within the hollow inner cylinder and above the base comprising a fixed volume, wherein the height and inner diameter of the inner cylinder determines the fixed volume; and 5) a second cavity outside the inner cylinder, but within the outer column and above the base, wherein any excess of fluid delivered to the first cavity will overflow and be retained in the second cavity without being delivered to the column device and only the fluid in the first cavity will pass through the hole in the base onto the column device.