Multi tank and compressor build for blasting

[conor1n]

Good evening

In order to progress this project - I have asked my landlord about installing the air system behind unit with plumbing through wall.

He has said, it's fine if insurance covers it.

I have been dealing with a broker who had a look around and is putting together the application / quote for me.

He expressed a little uncertainty about the "homebrew" nature of the air system. It's a bit mental considering, adding two compressors together for extra capacity wouldn't raise an eye brow. But as soon as he saw the two other "compressed air/gas tanks" he made sounds.. IMHO there is zero difference between these tanks and a bought in air receiver.. The system would be the exact same.

Has anybody ever had such a system inspected by an insurance engineer and has the outcome been positive / negative etc?

I explained to the broker that it was a widely accepted approach to adding air capacity. I think he was generally impressed with the layout of my unit and how organised it was. Every box / container on the shelving was labelled etc... perhaps this might instill confidence in an insurance engineer too?

 

[MetalMonkey]

I'm no expert but I would imagine any quality air receiver is going to have some sort of Lloyds Register rating or similar type approval which will satisfy the insurance company that it is fit for purpose. A homebrew solution made out of propane tanks, not so much.

At home, nobody (probably) is going to care - but if this is going to be a business, with all the insurance and paperwork that comes with it, I wouldn't even entertain the idea.

 

[conor1n]

I'm no expert but I would imagine any quality air receiver is going to have some sort of Lloyds Register rating or similar type approval which will satisfy the insurance company that it is fit for purpose. A homebrew solution made out of propane tanks, not so much.

At home, nobody (probably) is going to care - but if this is going to be a business, with all the insurance and paperwork that comes with it, I wouldn't even entertain the idea.

I see your point, to an extent. But the pressurised gas cylinders will be and should be certified on their own as they inherently much more dangerous and in more widespread use than any air receiver.

Would you not agree?

 

[Burdekin]

What you might find is changing service and modifying them the vessels are no longer PED compliant. You're correct in what you're saying regarding it's perfectly safe to change from propane to air but the vessel may only be certified for propane. You might be best getting CE stamped receivers or an old large knackered compressor.

 

[conor1n]

What you might find is changing service and modifying them the vessels are no longer PED compliant. You're correct in what you're saying regarding it's perfectly safe to change from propane to air but the vessel may only be certified for propane. You might be best getting CE stamped receivers or an old large knackered compressor.

OK that's fair, I hear you.

Would tanks from a HGV be OK from a compliance perspective do you think ?

 

[Burdekin]

OK that's fair, I hear you.

Would tanks from a HGV be OK from a compliance perspective do you think ?

I would only be guessing but if they are certified air receivers I'd imagine ok. You would come under PSSR2000 and should have a Written scheme of Examination. You are the user/owner under PSSR2000 and a competent person should put together a Written Scheme of examination, this details when to inspect the pressure equipment, what to inspect and how to inspect. After each inspection you then update the WSE. It sounds scary but is in reality straightforward. I have no idea if it's common practice in small firms but if you were to have an accident with the pressure equipment and didn't have any inspection history or WSE in place the HSE I imagine would prosecute.

 

[MetalMonkey]

Would you not agree?

It's not me you have to convince... it is the insurance company.
My experience of that is, if it is conventional and there is a box they can tick you are generally OK, but anything out of the ordinary and you are entering a world of hassle that you need to be very sure is worth the time/effort/money.

 

[DanZac]

I spent a bit I time inspecting and writing WSE for pressure systems, and can confirm that the chances of getting any insurance cover or a WSE on a homebrew system is pretty unlikely.

The person / company issuing the WSE is responsible for ensuring the safety and compliance of the system, and using non certified, (or using certified items for an alternative use) is unlikely to be acceptable, unless you can somehow prove the safety and design of the system and I'd suspect that that's just about impossible.

Your best bet is speaking to whoever is going to issue the WSE and see what they would accept. But by the time you've done that and messed around it'll probably be cheaper to buy an off the shelf solution that's already compliant and certified.

Also worth adding that if your going to be shot / media blasting as a business (I think that was the original idea?) you'll need approved extraction, breathing air, dust control, etc.

Unfortunatly doing things as a business is a bit more involved than just doing it for yourself in your shed.

 

[RWD3M]

Does anybody have any leads (names or websites) for looking up fittings?

Hi Conor,

I got all my stuff from these guys:

Pneumatic & Hydraulic Components - Duncan Rogers

Duncan Rogers offer precision engineered components, fittings & accessories at great prices for all our valued customers.

www.duncanrogers.com

Good prices and great availability and service.

 

[dave h 2]

OK that's fair, I hear you.

Would tanks from a HGV be OK from a compliance perspective do you think ?

Conor,
As others have said before.
The extra tanks will not give you what you expect, the extra air time will be cancelled by the extra time needed to run the whole system back up to pressure. If you have an 100L tank on a comp and you add an extra 100L tank it will now take twice as long to fill it.

For the cabinet your two existing comps in tandem will do. For your chassis work you can get an old road comp for 1500 quid and sell it later for the same with no complications if it doesn't work out.

Keep it simple stupid has a lot of value going for it.

 

[brightspark]

anything home brew on air tanks wont get insurance cover and any official tanks need a test certificate

 

[conor1n]

Hi Conor,

I got all my stuff from these guys:

Pneumatic & Hydraulic Components - Duncan Rogers

Duncan Rogers offer precision engineered components, fittings & accessories at great prices for all our valued customers.

www.duncanrogers.com

Good prices and great availability and service.

Thank you .. looks good.

Conor,
As others have said before.
The extra tanks will not give you what you expect, the extra air time will be cancelled by the extra time needed to run the whole system back up to pressure. If you have an 100L tank on a comp and you add an extra 100L tank it will now take twice as long to fill it.

For the cabinet your two existing comps in tandem will do. For your chassis work you can get an old road comp for 1500 quid and sell it later for the same with no complications if it doesn't work out.

Keep it simple stupid has a lot of value going for it.

Fair enough .. I suppose I was just powered ahead with the idea for two reasons - it was a cheap solution and wouldn't mind trading the expense of time to complete against forking out a lot of cash on day 1.

I've been getting on fine with a single motor and 200 litre for the cabinet - so I was just assuming that doubling everything might get me over the starting line with chassis work.. but then again...the "colouring in the whole chassis with a felt tip pen" analogy has sat in my mind and you guys are probably correct regarding needing bigger gear to support a bigger blaster nozzle!

Thanks for hammering that point home.

I see online there are a number of reasonably priced used compressors - Apart from Atlas Copco and Ingersoll Rand, what other brands are good? And what would be a reasonable limit on number of hours on machine? Thanks a lot!

anything home brew on air tanks wont get insurance cover and any official tanks need a test certificate

Fair enough. I'm seeing that now. I think I am going to bin that idea off tbh.

 

[dave h 2]

Sorry for the hammering, but you can't judge your time properly with a poor setup.
Screw Comps are better than Vane types as there's less to go wrong, although the screw ones do need a more expensive oil.

 

[conor1n]

Sorry for the hammering, but you can't judge your time properly with a poor setup.
Screw Comps are better than Vane types as there's less to go wrong, although the screw ones do need a more expensive oil.

No problem.. you guys are here to pick holes and throw stones through those holes in my ideas

I'm starting to disregard the idea of that 10HP 3 Phase vane compressor and look at used screw comps.. I am starting to see the pros of a screw comp such as 100% duty cycle and energy efficiency.. especially those VSD types. Question: Are non VSD screws still more efficient that vane?

Although if I am going to buy a compressor I feel like one of those diesel road compressors would be the one to go for..

I have seen some online for not bad money .. it's hard to know what you are getting though. How many hours on one is ok? And what are the brands to go for? Anything acceptable along with IR, Atlas?

 

[JOEPRO]

ABAC make good compressors. I have a 270L single phase tandem unit I bought used for cheap. Great machine very powerful perfect for blasting etc can't fault it.

Forget about bringing someone in to inspect etc - get a standard unmodified compressor.

 

[conor1n]

How many HP is that compressor and what kind of blasting do you do? If I hooked both my compressors together (without propane receivers..) then I would have 6HP and 250 litres.. similar to yours, i'd say.

Surely it's the propane receivers that are out of the question? Surely adding two compressors in series is not out of the question and not a questionable practice... surely?

 

[JOEPRO]

Don't call me surely.

Yes 2no 3hp motors and with the cfm police on this forum I will post the spec here:

Capacity - 27.6 cfm
Capacity - 786 l/min (Displ)
Pressure 145 psi /10 bar
Motor - 3+3 HP, 2.2+2.2 Kw
Receiver 270 l
Voltage 240 v

I use a 6mm nozzle in a floor standing blast cabinet and this comp will run it flat out and it actually turns on and off in the process it keeps up easily.

 

[DanZac]

Without getting all H&S, there's some brilliant advice here. But @conor1n really needs to decide if he's trying to get this set up as a buisiness (post 28), in which case he's probably looking at running stuff full out for 8 hours a day and he needs the relevant insurance, Written Schemes, Design approval etc that go with that.

Or just doing the odd brake caliper and bit of surface rust in his garage. In which case crack on with anything that'll work and hold your breath if it gets a bit dusty.

As far as I can see they're two very different situations and will need significantly different approaches. And there's not much point in setting up a hobby system, if the final goal is a business.

 

[conor1n]

Without getting all H&S, there's some brilliant advice here. But @conor1n really needs to decide if he's trying to get this set up as a buisiness (post 28), in which case he's probably looking at running stuff full out for 8 hours a day and he needs the relevant insurance, Written Schemes, Design approval etc that go with that.

Or just doing the odd brake caliper and bit of surface rust in his garage. In which case crack on with anything that'll work and hold your breath if it gets a bit dusty.

As far as I can see they're two very different situations and will need significantly different approaches. And there's not much point in setting up a hobby system, if the final goal is a business.

I hear you.. but.. i'm going to ease myself into this.. I understand you probably have industry experience from the tone of your post.

I don't plan on running these things 8 hours flat each day. Probably more like a few days a month really.. I do plan on getting insurance and am waiting to hear back from a broker. Will see what stipulations they come up with.

The reality is that you need to stretch some things going down the startup route.. it's not like I am being reckless and I won't be bringing people in to do the work.. so while this will be a business.. the day to day will be very similar to my own personal workshop.

 

[brightspark]

pity u wernt local you could have had a go of my twin unit comp and pressure fed blast pot i use open or in a cabinet using a 2.5mm jet or the road tow comp @ 90cfm with the 6.0mm jet to give you the idea what its about and the capability