Unusual paint sprayer question

[gmgmgm]

What an intriguing problem.

It's possible to get taps operated by motion sensors or floor-buttons. If you have sufficient pressure these could help. If you can't get the height, then a pump e.g. Whale could be ok. Presumably one rated for petrol/fuel should have no plastic inside it?

If you need to only squirt a small volume, then Covid made popular the motion-activated soap/gel dispensers, perhaps there's a way to change the nozzle so it sprays instead of "glugs". I don't know if they generate pressure or it's just gravity.

Your requirements for materials seem complex, but if you can find squirty bottles of the "right materials" then it seems likely you can get mechanisms like the above. I think you will find it easier if you can filter a larger volume of clean water at once - e.g. mass of 20L of water high up, leading down to a motion-operated spray tap should be reasonably simple to generate pressure + dispensing.

You can also get cordless/18v pressure washers these days. Rubbish for cleaning vehicles, but the fairly weak power could help here, if they meet the non-micro-plastic requirements. Better pressure washers are all brass, no plastic.

Another idea: those vertical glass-washer spray mechanisms in pubs: presumably they are 99% stainless steel, and could be ideal for washing beakers?

Perhaps the way to look at it is as two independent problems: pressurising; and dispensing.

 

[alex robinson]

What an intriguing problem.

It's possible to get taps operated by motion sensors or floor-buttons. If you have sufficient pressure these could help. If you can't get the height, then a pump e.g. Whale could be ok. Presumably one rated for petrol/fuel should have no plastic inside it?

If you need to only squirt a small volume, then Covid made popular the motion-activated soap/gel dispensers, perhaps there's a way to change the nozzle so it sprays instead of "glugs". I don't know if they generate pressure or it's just gravity.

Your requirements for materials seem complex, but if you can find squirty bottles of the "right materials" then it seems likely you can get mechanisms like the above. I think you will find it easier if you can filter a larger volume of clean water at once - e.g. mass of 20L of water high up, leading down to a motion-operated spray tap should be reasonably simple to generate pressure + dispensing.

You can also get cordless/18v pressure washers these days. Rubbish for cleaning vehicles, but the fairly weak power could help here, if they meet the non-micro-plastic requirements. Better pressure washers are all brass, no plastic.

Another idea: those vertical glass-washer spray mechanisms in pubs: presumably they are 99% stainless steel, and could be ideal for washing beakers?

Perhaps the way to look at it is as two independent problems: pressurising; and dispensing.

It is indeed a fun problem to think about. Pretty much any pump on this scale not specifically marketed as "100% plastic free" for a very specialised use will have some polymers in there somewhere. It could be as little as a tiny o ring, but it is enough to rule them out. A quick look at whale pumps and they appear to have plastic casings and the power cord for the submersible so will be shedding a lot.

A further problem with the gravity fed options is that as well as getting permission to drill holes in the building (we get a lot of freedom, but there are limits and that is highly unlikely!) the lab itself is at elevated pressure to keep contaminants out so it would need very careful sealing and recertifying.

Science can put some really irritating restrictions on what is possible sometimes and plastics are everywhere! Means things like being really careful about the fabrics you wear, no cosmetics etc. At least not quite as bad as one job I applied for at Pirbright centre for animal diseases. There they warned in the interview that I would have to avoid any close proximity to livestock. If I was on a walk at the weekend and a cow approached I would have to run away!