Volumetric filling

This paper describes the development of a system and facilities for safe, efficient, and accurate filling of white phosphorus (UP) munitions. This new development replaces dip-fill operations used by the U.S. Army for over thirty years, a production method that was hazardous to operating personnel and generated unacceptable quantities of phosphorus contaminated water and gas. The new development, Volumetric Filling, is relatively pollution free and exceeds the U.S. Army s standards for filling of white phosphorus munitions. 

A project (No. 5751274) was approved and funded by the Army s Production Base Modernization and Expansion Project Management Office to prove out the Pine Bluff Arsenal volumetric filling concept on a production basis. 

Description of the Pine Bluff Arsenal Volumetric Filling Concept... 

The Pine Bluff Arsenal white phosphorus volumetric filling system (U.S. Patents 4,002,268, 11 January 1976, and 4,043,490, dated 23 August 1977) was conceived and developed by Pine Bluff Arsenal in 1973 and has been used in filling UP munitions since early 1974. 

Figure 2. Pine Bluff Arsenal WP volumetric filling system.

Figure 5. Pine Bluff Arsenal phase 1 WP volumetric filling accuracy.

Figure . Front view of the first WP production facility using the PBA volumetric filling concept. Photo courtesy of the U.S. Army.

Future plans for our UP operations include the replacement of two remaining UP dip-fill production lines with the more accurate, efficient, and safer volumetric filling method described in this paper. 

The contributions of several Government organizations and employees contributed to the success of the Phase I and II development of the Pine Bluff Arsenal volumetric filling production line. Noteworthy support was provided by the following individuals ... 

Accuracy, volumetric filling of white phosphorus munitions, 171,173-174/ Air, ionized—See Ionized air Air blast waves, description, 3 Air locks... 

The volumetric filling ratio, X, can be evaluated from Eq. (2) in the steady state the angle subtended by the bed at the cyfinder axis, a(z), is computed from the local height H z), and the volumetric filling ratio is obtained by numerical integration ... 

The experimental and theoretical volumetric filling ratios are given in Fig. 5 for 12 experiments. 

It has been noted that the filling ratios obtained with the grid are generally larger than without for example, the volumetric filling ratio values can be compared between the cases 2 and 10 because the experimental conditions are close. 

Die fill characteristics depend upon material flow properties that are primarily affected by particle size and shape. Additionally, high interparticle friction can have a detrimental effect on die fill characteristics due to powder bridging and non-uniform flow characteristics. A non-uniform particle size distribution may also lead to material segregation resulting in uniformity problems. Tablet presses employ volumetric filling of the material into the die cavity. Most high-speed tablet presses are equipped with force feeders, which use rotating paddles to promote uniform die fill characteristics. For certain materials, attention must be... 

Example 22 Calculations for Batch Dryer For a 10-m batch of material containing 5000 kg dry solids and 30 percent moisture (dry basis), estimate the size of vacuum dryers required to contain the batch at 50 percent volumetric fill. Jacket temperature is 200°C, applied pressure is lOOmbar (0.1 bar), and the solvent is water (take latent heat as 2400 kj/kg). Assuming the heat-transfer coefficient based on the total surface area to be 50 W/(mr K) for all... 

An independent method uses a volumetric fill by a modified dosator method. The piston inside the dosator is narrower than those used for powder filling, and this allows air to flow between the piston and the dosator wall. The dosator is lowered into the pellet bed, but in this case, there is no compression applied. A vacuum source is applied from above the piston to retain the pellets as the dosator is moved above the capsule body. Once over the capsule body, the vacuum is removed, and the ejection of the pellets is aided by an air jet. 

An auger screw for powders or very viscous materials is another means of volumetric filling and relies on a number of whole turns or part turns of the screw. Weight fillers can be based on a bulk weighing plus a trickle feed fill-up. 

The volumetric filling factor of the pore space by water is defined as the liquid water saturation, Sr. It depends on the PSD and wettability of pores. Moreover, it varies with environmental conditions and the current density of fuel cell operation. The amount of liquid water arriving in the CCL is roughly proportional to/o> due to... 

After the volumetric filling, the dynamical phase which is dominated by the injection pressure of the filling process moves on to the quasi-static phase. This holding pressure phase can on one hand get the melt to compress and on the other hand deliver additional melt during the initial cooling, where the pressure in the cavity remains often almost constant. Such a post-supply of melt is possible as long as the gate, the junction of the runner into the cavity is still permeable (not yet sealed ). 

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