Steam Engineer or Boiler Makers

[bc_gold 71]

Recently fell victim to a bargain purchase, this 40 gallon Groen steam kettle, previous owner informed me the flame would not stay lit. After some research figured a faulty low water level sensor / controller be  the culprit.

 

The sensor probe was covered in iron oxide, the water jacket is full of the same,

 

The kettle is made from 304 stainless steel, with some removable brass,firrings any members here have a suggestions on how to clean the internal jacket.

 

[oliver2-44 9,745]

10 minutes ago, bc_gold said:

The kettle is made from 304 stainless steel, with some removable brass,firrings any members here have a suggestions on how to clean the internal jacket.

 

 

Can you show us a picture of the internals? 

Are they removable?

Are they a stean coil where you need to clean the inside and the outside?

Edited June 16 by oliver2-44

[bc_gold 71]

8 minutes ago, oliver2-44 said:

 

Can you show us a picture of the internals? 

Are they removable?

Are they a stean coil where you need to clean the inside and the outside?

 

Steam jacket is welded to the bottom of the cooking vessel, must be chemically cleaned. Just not sure what to use. Every chemical I have will destroy the stainless steel

 

 

 

Edited June 16 by bc_gold

[wh500special 2,179]

What chemicals do you have on hand that destroy stainless steel?  😳

If you’re trying to eat away the rust you might try citric acid or dilute nitric acid.  They will maintain the oxide coating on the stainless and should chew up the rust.  There is going to be some degree of contaminating the stainless steel itself with the dissolved iron as you do this so I would expect it to be a repetitive descale/rinse/Repeat process. 
 

We manufacture a mobile kitchen unit for the Army where I work and they are shipped with steam kettles similar to yours, but electric.  I think they have glycol or something in the jacket and not straight water.  Water can be quite aggressive. 
 

Steve

[bc_gold 71]

25 minutes ago, wh500special said:

What chemicals do you have on hand that destroy stainless steel?  😳

If you’re trying to eat away the rust you might try citric acid or dilute nitric acid.  They will maintain the oxide coating on the stainless and should chew up the rust.  There is going to be some degree of contaminating the stainless steel itself with the dissolved iron as you do this so I would expect it to be a repetitive descale/rinse/Repeat process. 
 

We manufacture a mobile kitchen unit for the Army where I work and they are shipped with steam kettles similar to yours, but electric.  I think they have glycol or something in the jacket and not straight water.  Water can be quite aggressive. 
 

Steve

Sulfamic acid, 93% sulphuric acid, hydrochloric acid,  35% hydrogen peroxide, nitric acid, I also have as you suggest anhydrous citric acid.

 

I have a lot of rhubarb, the leaves contain a lot of oxalic acid, was thinking of boiling up the leaves then using the juice as a rust remover.

 

Groen suggests distilled water in the jacket, again as you mentioned glycol is used by different kettle manufactures, and this is what I would prefer as the kettle will be used in my part time heated garage in central Canada where temperatures are very cold during the winter months.

 

Thank you for your input Steve. much appreciated.

[wh500special 2,179]

Of those, nitric would probably be my pick. I’m not sure what is a reasonable concentration but I’m sure it’s probably pretty low…like in the 10% range. 
 

While your goal is rust removal It’s worth researching passivation of stainless steel.  The goal is to foster the growth of the protective (ceramic) chrome oxide layer on the surface of the stainless steel.  That’s what prevents further degradation and corrosion.  Oxidizing acids like nitric and citric do this naturally.  I would guess you can get there with a mix of other acids and the h2o2 but you’d be in uncharted waters.  
 

If you find that one of the other acids is better at getting rid of the rust you’ll want to follow up with the nitric or citric before calling it a day. That will purge the free iron from the surface of the stainless.  
 

once passivated, the stainless steel is pretty bombproof.  Just keep it free of bleach or reducing atmospheres. 
 

Oxalic acid has some serious acute and chronic toxicity problems even in somewhat low doses.  It used to be sold at stores but I’m not sure if it is anymore.  I wouldn’t take my chances by concentrating it.  I don’t know how much rhubarb or spinach you’d have to amass to induce kidney failure but I suspect it’s a lot.  Still, not worth the effort or risk in my book.  
 

Of course, I’ve never heard of “death by rhubarb.”  
 

steve

[bc_gold 71]

I came across this interesting site, https://www.intechopen.com/chapters/68671

 

I used 35% h2o2 on the sight glass and some brass, brass from the bottom of the sight glass was completely clogged, beginning to think this kettle may never come totally clean.

 

 

[lynnmor 7,305]

When I made parts for NASA, they required passivation with certification on most things.  There was a local plating company that did it for a reasonable price.  Due to the size and complexity of your job it may not be an option.

[squonk 41,101]

When I was working on all of the kitchen equipment in the schools around here, they all had those Grown kettles. None of the schools ever used them . They just sat there taking up space. We just uh sed commercial descaler on any steam cooker we serviced.. The steamers at the hospital I work at now run R.O water in them.

[bc_gold 71]

7 minutes ago, squonk said:

When I was working on all of the kitchen equipment in the schools around here, they all had those Grown kettles. None of the schools ever used them . They just sat there taking up space. We just uh sed commercial descaler on any steam cooker we serviced.. The steamers at the hospital I work at now run R.O water in them.

 

The instructions, state when starting  the kettle the vacuum gauge on the steam jacket should read 30 inches vacuum. then with a full head of steam 30 psi. The relief valve on my kettle is factory set to pop off at 40 psi.

 

If there's no vacuum on the gauge this means there's air inside the steam jacket, air an insulator prevents the kettle from obtaining maximum heat.

 

I question why the school cafeteria people were not trained to use their Groen kettle.These kettle's for a small one like mine today's price $30,000.00 USD. Used full of scale and rust - scrap price.

 

 

[bc_gold 71]

Document, Nitric vs Citric Passivization Methods.

 

https://advancedplatingtech.com/wp-content/uploads/2019/07/Nitric-vs-Citric-Passivation-Methods-Blog.pdf

[bc_gold 71]

8 hours ago, wh500special said:

Of those, nitric would probably be my pick. I’m not sure what is a reasonable concentration but I’m sure it’s probably pretty low…like in the 10% range

 

Nitric acid all concentrations in bulk, ship in a stainless drum, the one I purchase looks like a beer keg with a hefty deposit.

 

From the chemical compatibility chart for 304 was surprised, citric acid is rated with a  "B".

 

Full document, https://marketing.industrialspec.com/acton/attachment/30397/f-00b5/1/-/-/-/-/304-stainless-steel-chemical-compatibility-chart-from-ism.pdf

 

 

Edited June 17 by bc_gold

[bc_gold 71]

On 6/16/2024 at 2:03 PM, wh500special said:

What chemicals do you have on hand that destroy stainless steel?  😳

If you’re trying to eat away the rust you might try citric acid or dilute nitric acid.  They will maintain the oxide coating on the stainless and should chew up the rust.  There is going to be some degree of contaminating the stainless steel itself with the dissolved iron as you do this so I would expect it to be a repetitive descale/rinse/Repeat process. 
 

We manufacture a mobile kitchen unit for the Army where I work and they are shipped with steam kettles similar to yours, but electric.  I think they have glycol or something in the jacket and not straight water.  Water can be quite aggressive. 
 

Steve

Steve on the propane units do you know the required  pressure setting  from the regulator.

[wh500special 2,179]

Ours are electric so no idea on propane pressures. 
 

Steve

[bc_gold 71]

Got the bugs worked out, first time fired this evening. Tomorrow is fat day.

 

The kettle is exhausted outdoors.

 

[bc_gold 71]

Maiden run, tallow and dog food.

 

[adsm08 2,052]

18 hours ago, bc_gold said:

Got the bugs worked out, first time fired this evening. Tomorrow is fat day.

 

The kettle is exhausted outdoors.

 

 

 

Then bring it inside and let it rest for a bit.

[bc_gold 71]

Liquid Gold.