Vaccine Unit

The vaccine unit is essentially composed of two subassemblies: A rotating tower with connectors for 64 holders and a base table with a bearing and seal. Figure below illustrates the all stainless-steel setup.

FIGURE 1

The holders are arranged at the periphery of a polygonal cylinder with 16 faces. There are four tiers. The airflow enters in the center at the bottom and flows through two plenums upwards. A cylinder occupies the core of the tower; its purpose is simply to restrict the airflow to a smaller annular section of the plenum thus maintaining the air velocity. This cylinder acts as a displacer. The inner plenum distributes the incoming flow; it has a decreasing cross-section so that the air velocity is kept at an approximately constant level in spite of 25% being diverted at each tier while flowing upwards.

The diverted flow enters individual holders and returns into the outer plenum via the same connector. The outer plenum has an increasing cross-section towards the top to accept the increasing return flow at each tier. At the top the air flows towards the center of the tower where it leaves the tower. The described assembly can be rotated to ease loading of the holders and visual control during the experiment. It is locked on a bearing flange with a visible hand release for instant separation. The base table carries the air inlet tubing, the bearing and the rotating seal.

The rotating tower can be disassembled to individual parts without tools. The plenums are clamped between the top and bottom flange with 8 tie rods. Disassembly requires removal of 8 knurled nuts and removal of the top flange as shown below.

FIGURE 2

Once done the inner cap closing off the displacer must be removed. The inner cap is visible on the picture above.

After removing the inner cap, the following parts are visible: in the center the cylindrical displacer and the two polygonal plenums. The top edges of the inner cylinder and the inner plenum must be at the same height when properly seated. The same silicon gasket seals the two top edges.

FIGURE 3

At this stage the two polygonal shells can be removed as one unit.

FIGURE 4

Note two marks at the top, inside, on each shell. The marks indicate the correct angular position of the two shells. To separate the polygons the outer shell is pulled upwards. Be careful to match the marks again when assembling. Never use tools to disassemble or assemble the plenums. This must be carried out manually.

FIGURE 5

The rotating tower is now fully disassembled. If necessary, one can still remove the silicone seals from the top and bottom flanges. The seals are 8mm thick, soft silicone gaskets.

The base table with the bearing is shown below. In the center the air inlet with a rotary seal. Around it the bearing flange. On the right, the lower flange of the tower with the displacer cylinder.

FIGURE 6

Figure below shows the bearing above the table and the air inlet (Tube dia 5/8") below extending to the right. The tube downwards allows collection of any back flowing liquids. A fitting for a pressure sensor (Tube dia 3/16") extends to the left. This Tee can be rotated.

FIGURE 7

The displacer below is shown upside down and still connected to the bottom flange. If necessary it can be separated form the flange by removing the 8 metric 5 nuts in the recesses. The locking handle and spring are then disassembled without tools. The parts shown below are normally not exposed to the experiment air with the exception of the inner hole. The lip seal seals against the face only millimeters around this center-hole. Outside of this sealing circle, the parts are exposed to atmosphere.

FIGURE 8

Air connectors

The air connectors comprise 4 seals, two O-Rings are used to maintain cages, on the opposite face there is one more O-Ring sealing against the outer plenum.

FIGURE 9

Figure above shows the two O-Rings used to center and maintain the cages.

The O-Rings are easy to remove and replace. In the center the air connector has one tube extending towards the inner plenum. This tube has 4 recesses to locate accurately the V-Ring. The recesses are visible on figure below. The V-Rings are more difficult to insert than O-Rings. Any fine tool is helpful to place the V-Ring at the correct recess.

FIGURE 10

The Pincers shown above are simply rotated around the tube to lower the V-Ring progressively. Due to the fact that the inner plenum is conical, the V-Rings must be located at different recesses according to the level. The lowest level, bottom level, has the greatest depth, the V-Ring is therefore located at the foremost recess. At every level the V-Rings have their own recess setting.

FIGURE 11

It is good practice to make 4 groups of connectors when replacing the V-Rings to more easily identify the level to which they belong.

Figure below shows 4 air connectors with V-rings located at different heights.

FIGURE 12