The plastic hose of your home vacuum cleaner is an example of a plastic pneumatic vacuum conveyor.

I am not aware of the application of plastic pipes (PVC or Nylon) in industrial pneumatic conveying installations. However, I suppose it must be possible.

I remember one experiment in the 1980’s in pneumatic grain unloaders, where the cleanup of the tank top of ship holds was done with the use of steel, manually operated, pipes.

The test was to try nylon pipes with a much lighter weight.

The result was that the operators got static electric shocks, which gave them a complete hairstyle make over.

The wear issue of plastic pipes in combination with hygienic installations should be addressed too.

As long as the conveying pipes can withstand the vacuum, it will work.

Take care ■

Originally Posted by Fortune44

If stainless gets wet or damp then it could corrode quite rapidly, does anyone know an alternative supplier that can manufacture vacuum conveyors in some sort of hard plastic?

I was in the salt business (evaporation and mining) for very many years and it sounds like you are not specifying the correct grade of stainless steel. 304 stainless for example (there are also lower grades) has a much higher carbon content than say 316 and therefore will tend to corrode over time and will be even less time if high moisture is present.

I would seriously look at 316L - we would never use anything else in high moisture areas and never had any corrosion issues. ■

Originally Posted by Fortune44

Hi all, I was a member a few years ago and I lost my password email so I have re registered.

We have a manual handling issue on site and it has been decided to go for a small vacuum conveyor to dispense approx 20-25Kg of granular salt bulk density Hydrosoft granular is ~1.25 - 1.3 gcm-3.

The problem is every person I have contacted have came back with stainless steel designs. The system does have to be hygienic, it is purely to transfer salt into a brine tank.

If stainless gets wet or damp then it could corrode quite rapidly, does anyone know an alternative supplier that can manufacture vacuum conveyors in some sort of hard plastic?

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Plastic conveying pipes do exist. In fact, they are used almost universally for unloading bulk containers such as rail cars, trucks, and ships. They do generate static, but these pipes have an internally-bonded grounding wire to transmit the static charge to ground. They are made from PVC, HDPE, LDPE, and any other plastic that is flexible. They are also used for temporary installations.

They are not used for conveying edible materials (foods) because there can be some wear of the internal surface of the pipe, leading to contamination of the food. If this is not a concern, plastic pipes can be used for conveying salt. Any pneumatic conveying vendor will supply hard plastic pipes for conveying if you so desire.

Regards,

Amrit Agarwal

Pneumatic Conveying Consulting ■