80results about How to "Uniform mass transfer" patented technology

Electroplating apparatus agitates electrolyte to provide high velocity fluid flows at the surface of a wafer. The apparatus includes a paddle which provides uniform high mass transfer over the entire wafer, even with a relatively large gap between the paddle and the wafer. Consequently, the processor may have an electric field shield positioned between the paddle and the wafer for effective shielding at the edges of the wafer. The influence of the paddle on the electric field across the wafer is reduced as the paddle is spaced relatively farther from the wafer.

The invention discloses a method for continuously preparing white carbon black and ammonium fluoride by carrying out fluosilicic acid ammoniation, which relates to a chemical production method, in particular to a method for preparing the white carbon black and the ammonium fluoride. The method comprises the following steps: (a) at a temperature between minus 5 and 30 DEG C, starting a stirrer and an air compressor, blowing compressed air into an outlet pipe of a reactor by the air compressor and adding fluosilicic acid and ammonia into the reactor simultaneously; (b) when the fluosilicic acid and the ammonia are added to the position of an overflow pipe in the reactor, opening an emptying valve to continuously feed and discharge materials and controlling a PH value of the reaction, wherein the period of the continuous reaction is 24 hours; (c) in the reaction process, filtering the materials discharged by the step (b) to obtain a white carbon black filter cake and filtrate of ammonium fluoride, and washing and drying the white carbon black filter cake to obtain a white carbon black finished product, wherein the filtrate is ammonium fluoride solution; and (d) after performing a reaction for 24 hours in the reactor, emptying the materials, cleaning the reactor to be used next time and producing the white carbon black finished product by using the materials according to the step (c), wherein the ammoniation yield of the process can reach 99.99 percent. The method of the invention effectively overcomes the defects of the existing intermittent technology and has the advantages of continuous, stable and simple process and long operation period.

A PX oxidation reactor for producing terephthalic acid comprises a reactor housing; the reactor housing is can-shaped, the ratio of height to diameter is 2.8 to 5, and the bottom of the reactor housing is provided with a distributed inlet duct and a spiral-flow type inlet duct; the distributed inlet duct comprises an upper air flow distribution tube and a middle air flow distribution tube, and theair flow distribution tubes are in the shape of circular rings; the number of spiral-flow inlet tubes is multiple, and the tubes are uniformly arranged surrounding the reactor wall. A combined air inlet gyration device used in the invention pushes the fluid at the bottom of the reactor by proper amount of air so that the reactor conducts rotary motion; the air has good dispersion and uniform distribution, and the material remains in normal suspended state; and the ratio of height to diameter between a high temperature reactor and a low temperature reactor is used, thereby avoiding non-uniformdistribution existing in the low temperature reactor with big ratio of height to diameter and also being better than the high temperature reactor in the aspect of low power consumption.