Antari snow machine pump.

[bigclive]

I noticed another thread where the poster had given up on their snow machine, but as it was in the advertising section I couldn't post a reply.

The most common issue for jamming of the little solenoid pumps in these machines (apart from gunk) is the smallest O-ring that fits in the groove at the end of the white plastic piston cylinder. These seem to expand over time in the presence of the fluids and ultimately they end up gripping the piston too tightly. I never found a good source of new accurately sized O-rings, but a quick fix I've used successfully a few times is to remove the O-ring and use a sharp Stanley knife to slice a tiny section out of it so that it still closes when put back into its groove, but is less tight on the piston.

[fliggygeek]

After being the sole tech on a winter christmas themed gig in australia, I have had to fiux a lot of these machines too. If its not the O-Ring, its possibly the main piston return spring thats fractured. Ive had at least 5 pumps have this issue, some of which were a direct result of being run dry or with large amounts of bubbles in the fluid.

[bigclive]

I've never actually come across a fractured spring, although I don't think any of these pumps were ever really designed properly for long term use with water based liquids. I've opened some and found serious corrosion and pitting inside.

 

Snow fluid in particular is quite hard on these pumps since the fluid is often 99% water (sometimes a mix of water and a volatile agent) with a tiny quantity of surfactant. Long periods of storage generally equals jammed pump. I've taken some apart where the little O-ring immediately popped out and couldn't be encouraged back into the groove at all. It was as if it was a larger size. Yet previous inspection of the same pump from new showed a perfect fit.

[MGLX]

I have a feeling I know the post!

The pump has suffered from corrosion, which the first few times I have been able to shave off enough corrosion to get it working. I now seem to be spending too long fixing this machine compared to the once a year it goes out, and thats normally as a spare with my other snow machine doing the majority of the work. Therefore if its useful to anyone as parts I would rather they get used, rather than binned or left rusting in the store.

[bigclive]

I still think that a better choice of pump for a snow machine would be a peristaltic pump, but they're really quite expensive for a decent one. Have you seen the long throw snow machines that look suspiciously like the blower unit from a standard snow machine mounted centrally on the front of an industrial fan? That could be a fun project to try with the bits from your old machine. (But doesn't solve the pump issue.)

[fliggygeek]

I still think that a better choice of pump for a snow machine would be a peristaltic pump, but they're really quite expensive for a decent one. Have you seen the long throw snow machines that look suspiciously like the blower unit from a standard snow machine mounted centrally on the front of an industrial fan? That could be a fun project to try with the bits from your old machine. (But doesn't solve the pump issue.)

 

I am under the understanding that peristaltic pumps are more expensive and wear out a lot faster than a solenoid pump, maybe why the cheap machines use them. Those long throw machines are actually really good, if you were really serious, a Martin Jem AF2 variable speed DMX fan with the guts of one of the snow machines would be a fantastic upgrade.

[Thunderlight]

Hi Don't wonna seem like the new comer here but I have had quite a few fog machine pumps go this way with the little O ring expanding. I cant recall what the last O ring I did was made out of, but I do know that standard nit-rile rubber O rings are terrible for reacting with chemical fluids. Viton O rings are allot less reactive and would probably be better! The sizes of fog machine pump O rings must be pretty standard so I'd have thought most fluid air power retailers would be able to get them readily. I understand on the job repairs need to be quick but for servicing repairs uprated O rings is the way! I will have to see if I can get the sizes and see what O rings I can source on the next one. At the moment its as quick for me to turn one up on the lathe in my workshop out of some PTFE bar stock.

 

Hope I've made some contribution!!

Tom

[bigclive]

I actually just took a pump to bits to see if the spring was showing any signs of corrosion, on the basis that if it was then that would itself reduce the springs force or even result in breakage as mentioned above. However, it was clean and shiny.

 

How are O-rings measured? The rings actual thickness is about 1.5mm but I'm not sure if they're measured as inner and outer diameter or thickness and a single inner or outer diameter.

 

Oh wait... I just Googled it! Wikipedia says that the rings are measured as the inner diameter and the cross section diameter (thickness). Most of the smaller 3 or 4mm ID ones seem to be 1mm thickness though.

 

It may well be that the ring is just 1mm thick to start with though, since the overall diameter expansion seems to have been quite considerable in the long term presence of water/glycol/surfactant. (It seems a common problem between snow and fog machines.)

[Thunderlight]

Yer they can be all different sizes! Best thing to do is to measure the slot/groove the Oring fits in then measure the bore the Oring slides in and use this formular: od- (2x width of slot). This will give you inside dia of the Oring which together with the slot width is your Oring sizes. If you go on a site called "bearing boys" under bearings and then seals/Orings you will find all the metric and imperial Oring sizes that are readily available in nitrile and viton!

 

Tom

[cedd]

Small O Rings of the kind of sizes you're talking about are also available in the world of remote control cars - used for sealing the oil filled dampers. I've got a box full of random bits, which includes a load of different ones.