That clemco blast pot...

[julianf]

New thread as the sales thread is now locked / closed -

The courier dropped it off this evening and I've had a bit of a look at it. It is fairly different from the generic red ones.

This is a diagram from the clemco site -

I'm going to run through my understanding and then, hopefully, someone can correct me where I'm wrong?

There's a big valve block on the side with a silencer attached. This seems to be controlled by some small pipe work to the dead man's handle.

It seems that the deadmans handle control causes the pot to depressurize, but this isn't clear to me. Something allows the pot to depressurize as that's what the silencer is for, that hangs off the side of the valve block.

There are two connections from the valve block to the pot itself. One to the mushroom valve and the other to the body of the pot. I'm assuming that the valve block first directs air to the mushroom and then, when the backpressure to that rises, it also sends air to the pot itself?


I don't have the hose / dead man's handle / control hoses. If they prove prohibitively expensive, I'm wondering if the valve block can just be replaced with a couple of ball valves. One to first pressurize the mushroom, and then a second to open up the flow to the body of the pot? Sure, the proper setup would be nicer but I thinking the handle etc may be multiples of the cost of the pot itself. Maybe not.

Anyway, is my understanding of the valve block operation correct? Mushroom, then pot body, then, somehow, dump the pot pressure through the silencer on release?


Thank you.

 

[frank horton]

needing a pilots licience now......

 

[hotponyshoes]

I had a foot pedal for the pressure pot I had.
It was a while ago but I'm pretty sure it had one inlet hole, one outlet hole and one release hole.
The release hole was just connected to the outlet hole.

So, the inlet went to the outlet when the pedal was depressed. When the pedal was released the outlet was connected to the release.
I think there was just a grill over the release hole but it would have been easy to screw in a silencer or add one remotely. That would have been worth doing as it sent up a cloud of dust from the floor whenever it was released and I'm pretty sure some of the dust was coming back out of the pot as well.

The outlet from the pedal went into the pot near the top. Presumably to stop it sucking grit back into the foot switch when it depressurised.

The down side was the lag from pressing the pedal until it had built up enough pressure to start blasting. Soon got annoying on smaller jobs.

My current setup has an electronic pedal that works a solonide that sends the air stright to a suction gun so it responds almost instantly.
One thing on the project list is to add a separate switch or find a latching foot pedal so I don't have to keep my foot on it.

I haven't studied the pictures of yours but why does it need a release?
Is there something that stops the pressure just discharging through the gun?

 

[julianf]

In short, I don't know. The unit is not operational currently, and im wanting to be certain of it's mode of operation before spending time and money either restoring it to factory design, or changing it to a different design.


I don't know if the dead man's handle controls the mushroom - I assume it must do as I don't think there is any other control. But it seems odd / wasteful to depressurize the pot the moment the handle is released, but I'm thinking there is no way to stop the air flow down the blast pipe without depressing the pot, so that probably is how it works.

 

[julianf]

Three photos below -

The control valve, where the hoses to the dead man's handle connect. (R)Ed and (Y)ellow.

The control valve showing the air inlet (low) that's currently sheered off, and the silencer unit (cylinder off the top)

The two connections from the control valve to the pot. The top one connects to a pipe that the mushroom stopper sits in (I think) whilst the lower one pressurizes the rest of the pot.

I assume the mushroom closes and then the back pressure on the pipe changes something in the control valve to then open the air to the lower connection. But, again, I don't know!

 

[Erie Fred]

I do know that there are different modes of operation, my 2 clemco's only operate the simple way of close the deadman, the mushroom
pops up, and pressurizes the tank, away we go. Let off the deadman, the tank de-pressurizes quickly thru the dump valve & muffler.

There is a set-up for "pressure hold" IIRC, and maybe that's what you have. From the little I read on it, that operation eliminates that delay,
for faster on/off operation. it keeps the pot pressurized.

I see your Clemco valves are different than what is avail "Over here".

2nd pix shows that rectangular aluminum valve, tiny quarter turn valve with bent down exhaust....looks like the valve used by a pot tender,
when they want to fill the pot (and the operator is 50' away in some tank/bulkhead) it negates the signal from the deadman, so it makes it safe, won't come on.

 

[brightspark]

take the top elbow off fit a reducer and connect just it to an airline and pressurize it if it just works the popup valve the rest is easy to alter without the deadman

 

[Erie Fred]

take the top elbow off fit a reducer and connect just it to an airline and pressurize it if it just works the popup valve the rest is easy to alter without the deadman

My neighbor removed the deadman on his brand new pot ($5000 set-up) as "I don't need no %$#@! safety devices".

What he did NOT understand, as he was doing tank blasting (crawling inside large tanks) is that with the on/off control of the deadman,
he could cycle the pot, to clear any plugging problems, without climbing out.

Also they make extensions for the top of the pot, where he could have filled the pot, and then added a few more bags on top.

When blasting and you run out, simply shut down using the deadman, wait a few moments for the mushroom to drop, and the reserve sand
to flow down into the main pot, push start on the deadman, and keep going.

Yes, they were originally made for OSHA compliance, but they do make operating the pot better/easier as well.

 

[julianf]

take the top elbow off fit a reducer and connect just it to an airline and pressurize it if it just works the popup valve the rest is easy to alter without the deadman

You mean just to initially see if the air flow is enough to lift the mushroom, and then go on from there if it's a "go-er"?

 

[brightspark]

My neighbor removed the deadman on his brand new pot ($5000 set-up) as "I don't need no %$#@! safety devices".

What he did NOT understand, as he was doing tank blasting (crawling inside large tanks) is that with the on/off control of the deadman,
he could cycle the pot, to clear any plugging problems, without climbing out.

Also they make extensions for the top of the pot, where he could have filled the pot, and then added a few more bags on top.

When blasting and you run out, simply shut down using the deadman, wait a few moments for the mushroom to drop, and the reserve sand
to flow down into the main pot, push start on the deadman, and keep going.

yes ideal for commercial setup where times .money home use its not so critical and not needed

 

[Erie Fred]

yes ideal for commercial setup where times .money home use its not so critical and not needed

Time is money, or aggrevation ?
I don't do it for money.

 

[julianf]

I see your Clemco valves are different than what is avail "Over here".

2nd pix shows that rectangular aluminum valve, tiny quarter turn valve with bent down exhaust....looks like the valve used by a pot tender,
when they want to fill the pot (and the operator is 50' away in some tank/bulkhead) it negates the signal from the deadman, so it makes it safe, won't come on.

I've not seen any photos of the square valve block. All that I can find are cylinders. I reckon this one is fairly old.

I was wondering what the small bass valves were.

 

[Erie Fred]

I've not seen any photos of the square valve block. All that I can find are cylinders. I reckon this one is fairly old.

I was wondering what the small bass valves were.

The one on the left side, photo #2.
with the red & yellow markings.

 

[brightspark]

i had one pot i built out of a 47kg propane bottle and would fill with 3 bags of grit well enough for 8 car wheels i also sandblasted my house with it using new grit . once regulated it never blocked or gave any hassle

 

[brightspark]

its the bottom side inlet pipe that feeds the popup valve https://www.hodgeclemco.co.uk/wp-content/themes/Hodge Clemco/images/photos/Product-Catalogue-PC7-web.pdf its well doable to get rid of the dead man and alter the pipework and fit a couple of ball valves to operate

 

[Erie Fred]

i had one pot i built out of a 47kg propane bottle and would fill with 3 bags of grit well enough for 8 car wheels i also sandblasted my house with it using new grit . once regulated it never blocked or gave any hassle

Same here, I used a large acetylene cylinder, just had ball valves.
Hand pull up operation.
I must have run thousands of pounds thru it.
I kind of guessed at the proportions, and it came out very well.
can run on as low as 5hp compressor, and does well on my 10hp too.

 

[Bond]

Pretty sure I have a spare clemco hose and deadman switch, I’m working away this week but I can have a look when I get back. I’ll sell it for sensible money if any use to you

 

[julianf]

Pretty sure I have a spare clemco hose and deadman switch, I’m working away this week but I can have a look when I get back. I’ll sell it for sensible money if any use to you

Possibly, but...

Because I'll be running this on a lower air supply than most do, I'll need a smaller bore hose than is common.

I mean, I'm keen, but I can't be sure if what you have will be applicable. Although I guess the control pipes and switch would be, even if the hose itself wasn't.

Let me know when you're back and we can both see. Thank you.

 

[Bond]

No bother will do. From memory it’s a simple circuit one hose has air flowing out the handle has a rubber bung so wen u close it it completes the circuit and that pops the mushroom thing up and pressurises the pot.

 

[brightspark]

the only thing you might have to watch is that the pop up valve may need a high ish pressure for it to operate and stay closed so if comp isnt up to it and drops in pressure it may fail