Pressurized delivery systems testing

Pressurized delivery systems include inhalers (meter dose and dry powder inhalers), foams, and sprays. The appearance test consists of two parts the examination of the... 

Detergent Additives. Diesel engine deposits are most troublesome in the fuel delivery system, ie, the fuel pump and both fuel side and combustion side of the injectors. Small clearances and high pressures mean that even small amounts of deposits have the potential to cause maldistribution and poor atomization in the combustion chamber. The same types of additives used in gasoline are used in diesel fuel. Low molecular weight amines can also provide some corrosion inhibition as well as some color stabilization. Whereas deteigents have been shown to be effective in certain tests, the benefit in widespread use is not fully agreed upon (77). 

Vahlas and coworkers recently tested a new delivery system based on sublimation in a fluidized bed, to improve mass and heat transport. A mixture of solid Al(acac)3 (minor component) and inert alumina or silica particles was fluidized with a combination of water vapor and oxygen at 150 °C, by which amorphons AI2O3 films were obtained on Ti6242 alloy wafers immersed in the bed. Pauleau and Dnlac compared the kinetics of vaporization of Al(acac)3, Al(tfac)3 and Al(hfac)3 by isothermal TGA. The satnration vapor pressure of Al(hfac)3 is 10-fold and 100-fold higher than those of Al(tfac)3 and Al(acac)3, respectively. 

The solvent delivery system is responsible for delivering the pressurized mobile phase with the desired composition and chosen flow rate to the head of the column. To achieve this goal a number of components work together under the supervision of the system computer or microprocessors to achieve the tight specifications typical of a modem liquid chromatograph. Table 5.2 [15-19]. Suitable tests for performance evaluation of solvent delivery systems are briefly described at the end of section 5.2.2. In retention terms a relative standard deviation of better than 0.15% for retention factors under normal operating conditions is expected. 

The delivery or header system usually consists of flexible hoses and rigid pipes. The design of this system must be coordinated with the plant layout, the material to be dispensed, and the instantaneous material delivery rate required. The two primary factors are material and delivery rate. Each material to be dispensed (adhesive or sealant) requires a unique and specific pumping pressure based on header size (hose and pipe inner diameter) and delivery rate. Calculations should be made to estimate system pressure drop for a proposed system configuration to determine if sufficient system pressure availability exists. Tests should also be conducted to verify system design. These calculations and tests should take into account... 

The instruments for the HT-HP filtration test consist essentially of a controlled pressure source, a cell designed to withstand a working pressure of at least 1000 psi, a system for heating the cell, and a suitable frame to hold the cell and the heating system. For filtration tests at temperatures above 200°F, a pressurized collection cell is attached to the delivery tube. The filter cell is equipped with a thermometer well, oil-resistant gaskets, and a support for the filter paper (Whatman No. 50 or the equivalent). A valve on the filtrate delivery tube controls flow from the cell. A nonhazardous gas such as nitrogen or carbon dioxide should be used for the pressure source. 

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