US Patent 7478673 Frac head including a mixing chamber

An improved frac head includes a mixing chamber located in an internal bore downstream of an intercept between the side ports and the internal bore and upstream of a tapered vortex portion of the bore. The tapered vortex reduces the diameter of the bore from a first diameter to a second diameter. The length of the mixing chamber (along the longitudinal axis of the frac head) is advantageously greater than the first diameter. The ratio of the first diameter to the second diameter is further advantageously greater than 1.5. Frac heads in accordance with this invention tend to undergo significantly reduced erosion as compared to frac heads of the prior art thereby improving service life. The invention also advantageously obviates the need for deployment of erosion resistant sleeves (or other wear resistant liners) in the interior of the frac head.