Drying process control

Bennett DB, K. BT, Snyder HE, Platz RM, Inventors Nektar Therapeutics, Inc., assignee. Spray drying process control of drying kinetics. US patent 20030044460, 2000. 

M.M. Stefanovic and M.B. Stakic, Fuzzy expert system for drying process control. Proceedings of the I2th International Drying Symposium IDS 2000, 2000. 

Rybicki A., Drying Processes Control of Materials Susceptible to Shrinkage Damage. Computer Simulations, Poznan University of Technology, Poznan, Poland, Transaction No. 482, 2012 (in Polish). 

Microwave-Assisted Drying Process Control and Optimal Operation... 

A wide variety of particle size measurement methods have evolved to meet the almost endless variabiUty of iadustrial needs. For iastance, distinct technologies are requited if in situ analysis is requited, as opposed to sampling and performing the measurement at a later time and/or in a different location. In certain cases, it is necessary to perform the measurement in real time, such as in an on-line appHcation when size information is used for process control (qv), and in other cases, analysis following the completion of the finished product is satisfactory. Some methods rapidly count and measure particles individually other methods measure numerous particles simultaneously. Some methods have been developed or adapted to measure the size distribution of dry or airborne particles, or particles dispersed inhquids. 

Flame Retardants. The amount of research expended to develop flame-retardant (FR) finishes for cotton and other fabrics has been extremely large in comparison to the total amount of fabrics finished to be flame retardant. The extent of this work can be seen in various reviews (146—148). In the early 1960s, a substantial market for FR children s sleepwear appeared to be developing, and substantial production of fabric occurred. In the case of cotton, the finish was based on tetrakis(hydroxymethyl)phosphonium chloride (THPC) or the corresponding sulfate (THPS). This chemical was partly neutralized to THPOH, padded on fabric, dried under controlled conditions, and ammoniated. The finish was subsequently oxidized, yielding a product that passed the test for FR performance. This process is widely preferred to the THPOH—NH process. 

One issue with the GBS treatment (and silane-coupling treatments, in general) is that the performance can be highly dependent on processing conditions, especially hydrolysis and drying conditions. Nonetheless, process controls suitable for field application of bonded repair patches are possible. 

Nutsche filters are constructed to perform a multitude of tasks including reaction, filtration, cake washing and thermal drying on a single unit. As such these are very sophisticated machines with tight process control on parameters such as pressure, temperature and pH. 

There are two processes used to manufacture cements the dry process and the wet process. The dry process is the least expensive of the two, but is the more difficult to control. 

The quality control unit in a cosmetics company supervised the processing of the weekly batch of shampoo by determining, among other parameters, the viscosity and the dry residue. Control charts showed nothing spectacular. (See Fig. 4.10, top.) The cusum charts were just as uneventful, except for that displaying the dry residue (Fig. 4.10, middle and bottom) The change in trend in the middle of the chart was unmistakable. Since the analytical method was very simple and well-proven, no change in laboratory personnel had taken place in the period, and the calibration of the balances was done on a weekly basis, suspicions turned elsewhere. A first hypothesis,... 

Thus, in the observation of the drying process of biological materials, the water activity is at least as valuable as the water content of a material. As water activity measurements are complete in about 3 min, they represent a useful tool for control of the drying process. 

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