Propellant mixing

In the plastisol propellant process, it is essential that the resin particles not solvate too rapidly at processing temperature since a rapid increase in viscosity of the propellant mix interferes with the mixing and casting operation. There must be adequate pot life of the mixed propellant. The resin-plasticizer system itself is the dominating influence on pot life, and for this reason certain combinations cannot be used in the plastisol process. 

The wetting agent in the propellant composition is used to facilitate the mixing of ingredients and to reduce the viscosity of mixed propellant so that it is more easily cast. The wetting agent listed in Table I was also used by Rossen and Rumbel (9). 

With binder content held constant, an increase in aluminum content is obtained at the expense of ammonium perchlorate content. Since aluminum has a greater density (2.70 gm./cu. cm.) than ammonium perchlorate (1.95 gm./cu. cm.), this exchange can greatly increase the fluidity of the mixed propellant, particularly if the aluminum which is used is spherical or spheroidal in contrast to the shape of ground ammonium perchlorate. 

After mixing, the propellant is transferred into a casting pot, a container in which it may be held and from which it may be cast. The long pot life of mixed PVC plastisol propellant permits it to be held almost indefinitely to meet the convenience of the production schedule. The long pot life also makes possible the full characterization of a batch of mixed propellant, by extensive tests on batch samples, before the batch is committed to further processing. 

Continuous screw extrusion is another way to form PVC plastisol propellant into the desired size and cross-sectional shape. Simultaneous curing of the propellant is also accomplished. This process has been described fully by Rossen and Rumbel (9) and is only summarized here. Mixed propellant is fed from a casting pot into the feed end of a continuous worm-screw extruder which is fitted at the discharge end of the screw with a device for constricting propellant flow. The action of the... 

The impeller is the part of the agitator that impacts force to the material being mixed. Propellers, turbines, gates, anchors, and paddles are all types of impellers. Typically, the impeller is a single propeller or turbine blade connected to a shaft that is driven by an electric motor at a fixed speed. There are two classes of impeller agitators axial-flow and radial-flow, and the mixing characteristics are shown in Figure 3.14. 

Polymerization of prepolymer or monomer component of mixed propellants to increase mechanical strength. 

One final problem encountered with stirring was related to the strength of the aluminum fan. The adapter on the aluminum fan was not sufficient to withstand the reaction torque generated by the density of the SCF and subsequently allowed the fan to spin on the adapter and deform the fan blades. The aluminum fan was removed and a three-blade polished stainless steel mixing propeller was procured. The magnetic drive assembly was removed and the shaft... 

The vapor pressure of the formulation in a pMDI can be adjusted to a targeted value by mixing propellants with different vapor pressures. Propellants offer the additional advantage of having a narrow density range that may be adjusted to balance the density of the drug particle in suspension. ... 

C.W. Eilo, USP 3261732(1966) CA 65, 10419(1966) (The prepn is given of a novel aq slurry blasting agent which is stable when particulate Al and an AcOH—21nO stabilizer are present. For its prepn are mixed propellant 30.0 parts, water 18.0, pine oil 0.1... 

The pintle injector is unique among the various injector options which have been successfully used in hquid rocket engines. Many early liquid engine injectors utilized impinging jets that create a spray due to the impact of the two streams, or coaxial injectors that mix propellants from shear or swirl induced in the inner fluid. These injector types are implemented in a flat face injector plate at the head-end of the combustion chamber. This resultant flowfield shown in Fig. 28.1c yields a curved spray/combustion zone which is substantially different than those formed by flat face-type injectors. 

Fig. 4.54 Chest mixing propeller with horizontal axis (source Voith).

For large storage volumes towers are used with reduced diameters at the bottom. Only this lower part is agitated by a mixing propeller. In this case stock can also be stored at higher consistencies, even above 10%. 

Improvement is insufficient the soil adhered onto the mixing propeller and the screw became like a rod and transport was difficult 11.1 12.0 A slight mqnovement was noticed with transportation 9.5... 

The condition of the treated soil is relatively good however, as with item 4, the soil adhered to the mixing propeller 3.1 11.0 There is no change with transportation 3.0... 

The experiments were conducted in the constant volume 2.2-L vessel with 80 mm diameter quartz observation window on the side, gas mixing propeller on the bottom and injector on the top, as shown in Fig. 23.2. The ambient condition inside the vessel was made to be high temperature and pressure by igniting hydrogen in an enrich oxygen and air mixture. The oxygen concentration after the hydrogen combustion was approximately 21% by volume (Azetsu et al., 2003 Matsui et al., 1979). 

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