Portable Industrial Vacuum Systems

Vacuum systems have always been used industrially to transport liquid products such as water, slurries or slurries, as well as dry products. This vacuum system may be truck based, or alternatively, on a portable platform such as a trailer or skid. A common question is how far the product can be transported, and how close the vacuum unit should be to the job. This paper answers the question for moving liquid products with a Liquid Ring pump based vacuum system.

For liquid products, it makes no difference how far you can run horizontally (up to 400-500 feet) as long as you use good seals and gaskets to prevent vacuum loss. Make sure you don’t experience any additional (unnecessary) kinking or lifting or lowering of the hose. It should be as straight as possible on a flat track. Use a slow 90 degree radius spin. The bend in the line reduces the loading rate significantly. Your vertical lift will be the hardest part of the process. No machine will lift a solid column of water more than ~30 feet. You can make very high lifts (over 100′) vertical if air is allowed to enter the column. Make sure your hose is not buried in the product for a long time….the system needs to swallow air.

You cannot burn a liquid ring vacuum system by burying the hose in the product; it will only make hot water in the water tank. When that water finally evaporates, you will lose your vacuum. When you add water back into the tank, your vacuum will return.

Hard tubing will greatly improve your flow by reducing friction losses. Maybe you can’t use it, but if possible, use it. (Hard tubing is usually Schedule 80 PVC, glued in a straight line, flanged cleaning at 90° slow radius, threaded end for flexible suction hose). Descending works best if you suck into the container. If it’s possible to do this, do it.

In general, larger diameter hoses provide greater vacuum efficiency and higher loading rates. Changing the diameter of the hose along the length of the suction hose can be a problem. Air velocity is directly dependent on the diameter of the hose, and variations in air velocity can cause blockages in solid products.

Hoses with a 4″ diameter can be handled by one person. Hoses with a diameter of 6″ require frequent disconnection or tag-teaming by two people. A better alternative is to use a wheelbarrow or a broom or sweeper to transfer the product to the hose. It is also possible to remove the intake and have two hoses working at the same time, under the right circumstances. A wand is available for the end of the hose to facilitate product retrieval, and often a makeshift grip is made of brooms and duct tape.

For solids, a 6″ hose can generally handle a maximum diameter particle size of 2″, a 4″ hose can handle 1″, and a 2″ hose can handle a maximum particle size”.

As indicated, hard tubing is best for reducing friction losses. If you don’t have tough piping, the next best thing is a smoothbore hose. Corrugated polyethylene hoses are lightweight and easier to handle, but long corrugated hoses can reduce speed dramatically. Most of the length of your hose should be hard tubing or fine bore rubber hose, with only the last part of the working end (<30′) being lightly corrugated hose.