The Bench Top O’Brien Agglomerator
Quick Start and Safety Information
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Receipt and Assembly
Assemble and test-run the Agglomerator per the Installation Instructions (not shown here)
Safety Concerns.
For Benchtop Agglomerators sold in the US, the motor is 110 ac single phase. The motor will pull about 5 amp maximum. Be sure the supply circuit is adequate.
There are a number of rods that stick out a short distance from the end of the drum. Even though the rotation speed of the drum is relatively slow, injury is possible. Be sure personnel are clear of these rods.
Pressurized liquids are used. Wear eye protection.
Operation
Electrical.
There are three electrical controls.
The black motor rotation speed control with
orange speed knob.
The Main On/Off Button
Rotation direction toggle (on side of frame - not
shown here(
1.The Main ON/OFF pushbutton locks out all electrical when the Main ON/OFF is pushed. The red light inside the switch indicates when it is energized ON.
2.The rotation direction of the drum is controlled by the TEST/EMPTY toggle switch on the side.
The motor should be OFF before changing rotation direction.
3.The rotation speed is controlled with the orange knob on the controller. The minimum speed (full CCW) is 2 rpm. Maximum rotation speed (full CW) is about 8 rpm.
Note there is a slide switch (RUN/STANDBY) on the controller. This slide switch is normally always in the RUN position. It is possible to use the STANDBY position for stopping rotation, but not recommended. The ON/OFF pushbutton blocks all electricity to the controller, where the slide switch does not.
The white belt
There are four slots cut into the drum near the front.
The picture to the right shows one slot exposed by
moving the white belt.
The procedure to empty the drum is as follows:
Drum rotation is OFF. The TEST/EMPTY toggle is switched to EMPTY. A suitable container is positioned under the drum. The white belt is loosen and repositioned to expose the slots. Retighten the belt.
Start drum rotation CW. The test material will spill out the slots and into the container. Often the batch size is greater then the container. Stop and start the rotation as needed using the ON/OFF pushbutton.
When repositioning the white belt for test purposes, be sure there is no powder on the outer surface of the drum that might cause a powder leak.
Retighten the belt sufficiently that it will not slide on the drum. Do not over tighten.
Normal Test Sequence
Below are the steps normally taken for making a typical agglomeration test run.
a) The drum rotation is OFF.
b) The drum is empty and the white belt is in place over the slots. The TEST/EMPTY toggle is in the TEST position. The spray boom is not yet placed into the drum
c) Charge the drum with the powder base. The amount to use depends upon several variables. This is discussed further in the Operation Manual. Simply put, the bed must be deep enough to for proper spraying, but not so full that material spills out the front of the drum or interfere with spraying.
If the powder base needs mixing, temporarily rotate (in TEST position) the drum to mix the powder base. Dye studies have shown that a good mix with “normal” sized material is achieved after about two minutes of mixing. Shut the rotation off.
d) Set up the spray system per the Installation Manual.
There are two liquid spray methods normally used. For thicker liquids, use the air pump. For lower viscosity liquids, such as water, it can be more convenient to pipe the Spray Boom directly to an existing connection, such as a water outlet.
Users often use pipe fittings to make a simple spray vessel. This can be sealed and, using air pressure, spray the liquid.
Liquids are introduced into the Agglomerator by pouring them into the small container.
The spray pressure will produce a flat spray pattern.
Normal spray pressures are between 5 and 15 millibar (19 to 30 psi). Higher pressures may be needed, especially with thicker liquids, but should not exceed 50 millibar (100 psi). If higher pressures then this are needed, contact Techmachine. It can be done.
Note that if an air pump is used, the final spray pattern will pulsate. This is normal and will not cause a processing problem.
Start drum rotation. When using a new formulation, start off at minimum rotation speed. As the rotation speed increases, the Rod Cage will lift powder to form the “falling curtain”.
Start the liquid spray (PRESSURIZED LIQUIDS – WEAR EYE PROTECTION!). Adjust spray pressure using the needle valve on the spray bar.
Be sure the flat spray is aimed directly into the “churning” powder bed or powder curtain. It is important that the liquid is not sprayed onto any metal inside the agglomerator. The liquid binders are normally very sticky and can easily cause processing problems (“a sticky mess”).
“Rules of thumb” when making a test run, especially initial runs of new formulations:
a) Use as fine a spray as possible. Generally, a greater distribution of the binder, especially quick drying binders, will produce the best results in the shortest time..
b) Use a STOP/START technique on the spray. Spray, say, 25% of the binder. Stop spraying for a few minutes leaving the drum rotating. Be sure the powder is not "sticky" (consistency of wet snow). If not, spray another 25%, stop again. Repeat until all the binder is sprayed.
This technique will help avoid over-agglomeration. Experience has shown that once the processing end point is reached, a small amount of additional binder can cause problems.
c) Due to the movement of the powder base within the agglomerator, liquid sprays do not have to cover the total length of the agglomerator. It is helpful for better binder distribution to cover as much as is possible. If multiple nozzles are used, the spray should not overlap. There is a possibility of buildup on the metal parts.
Drying. Often there is a need to dry, or condition, the product after spraying. This is usually to dry-off a few percent excess moisture or de-dust the batch or for other reasons. The finished agglomerate can remain in the Agglomerator and tumbling continued after spraying for this purpose.
The gentle motion within the rotating drum will not degrade particle size or promote continued agglomeration. some batches are tumbled for hours, even over night, without powder breakdown.
During drying, rotation speed can be increased to optimize exposure to the air. Heat can be added with a small hand-held dryer (like a hair dryer) or other methods. If using heat, be sure to increase dust collection capacity to compensate for the air flow.
When the batch is finished, stop drum rotation. Position a suitable container under slots in the drum. Loosen the white belt, slide it back (material will fall out of the drum) and retighten. Turn the orange speed control to minimum (full CCW).
Toggle the side switch to EMPTY.
Start drum rotation. The spiral inside the drum will push the agglomerates towards the front of the drum. Stop/start the drum as needed to empty the container. Speed up rotation as the batch empties if desired.
Note that the drum will “almost” completely empty.
Typical Batching Ended.