Smallest atex approved, stainless steel pump there is?

[MartinLe]

I accoasionally need to specify a pump for a small condensate shaft in sewage gas or similar application. My specs are:

* Atex approval (approved for explosion hazard zones)
* stainless steel - 1.4436 or similar
* small - condensate inflow as low as 10 l/h

This does not seem to exist. The smallest one I found so far is this, but with a 0,7kW motor (dunno why Homa won't list the smaller motor on it's site). Still vastly oversized with 12m³/h @6m.

An oversized pump needs a deeper and larger shaft.

I spent some time at IFAT a few weeks back talking to pump manufacturers and was told that small pumps that satisfy my other two requirements don't exist: For atex approval, you need a good thermal management that can only be done with cast housings, and the market is too small to justify this. Smaller pumps are made with a sheet metal housing and then you don't get atex.

My question is first and foremos if a smaller pump than the one I linked to exists that satidfies my other criteria.

Can I relax my requirements - don't quite see how:
There are ways around the atex requirement, by ensuring the shaft is not a hazard zone or the pump is always completely submerged but often you have a stubborn atex peron on the customers side.

Are there alternatives to stainless in these applications? Plastics could be as corrosion resistant but I guess the thermal proerties would be worse, no?

A suction pump mounted outside the shaft would still face atex issues (if it draws air) and mounting the pump in the shaft takes care of frost issues.

 

[micalbrch]

What are the ATEX requirements? Condensate is not flamable. So, a zone inside the pump does not exist here. Now the question is what is the requested classifaction at the installation point, zone 1 or zone 2?

The pump must lift a suction head and can eventually run dry? What is the max. suction head the pump must lift?

 

[MartinLe]

Zone 1 above the liquid level in the shaft.

To be clear, my primary question is about a a submersible pump.

I consider a suction pump as an alternative and I have put less thought into this.
about 3m suction head
IMO a zone inside the pump exists unless I can ensure that it will never run dry (draw air from above the liquid level).

 

[micalbrch]

A zone inside the pump can only exist if the fluid itself is flamable. If not, nothing will happen, not even with oxygen (air).

Yes, I understood that you were looking for a submersible pump but I'm not aware of such a small pump. If you consider a suction pump have a look at peristaltic pumps (Watson Marlow or Verder, just to name two manufacturers).

 

[MartinLe]

Now I understand the confusion with the zones:
The condensate is from sewage gas pipelines, the siphon separating condensate shaft and pipeline is not considered permanently gas tight so the the shaft is an ex zone because gas from the pipeline could be there. So if the pump draws air from the shaft ...

aPeristaltic pumps would be my first bet when going with the suction pump, followed by pc, with an eye towards longevity of wear parts.
Another idea I had is an pneumatic double diaphragm pump with a compressor mounted outside the shaft but I've seen so far none for submersible duty.