What are the concerns/safety of an unfired >100C vessel

[cyberbadger]

Does anybody have this happen to their tailstock(See end of the video)?

This Lathe is a Grizzly Benchtop 19". When it catches like this the tailstock handle turns backwards and you have to get your hands out of the way and hit the power.

This is a replacement tailstock that is brand new!!



It has to be operator error...

http://www.youtube.com/watch?v=-kM9r7zjtRg


-CB

[marinesteam]

Hard to tell from the video,

Two possibilities;
1. You have extended the barrel (the extending part) beyond it's guide pin or key
2 The pin or key is missing. If the barrel retracts without needing to be re-aligned, this is the most likely.

Scroll down to the tailstock diagram http://answer2questn.blogspot.com/2014/ ... lathe.html

Cheers

[Lionel Connell]

It looks like you have over extended the tail stock spindle and the spindle has disengaged with it's key. Normally, the tail stock screw would run out of thread ( stop pushing the spindle forward) before the key disengages. It looks like it is either a design fault, or that there is a problem with the way that the tail stock has been assembled at the factory.

Tail stocks have two common outcomes when they reach the end of their designed travel length dependent on the particular design .

1, Is that the lead screw disengages from the nut, i.e, the screw is too short to push the spindle far enough to disengage from the key.

2, That there is a smaller screw with a large washer in the end of the main screw shaft that acts as a stop and will not allow the main screw to exit the nut. This small screw is accessed though the end of the tail stock spindle, pull out the drill chuck and look inside with a flash light. If you see a threaded hole in the end of the main screw, this is where the stop bolt should be.

Cheers

Lionel

[cyberbadger]

PV Steam Test #1

Result: Pass

Still need much better structure, especially if I intend to use the large whistle - the piping fell over in the video.

What is the knocking that is happening at 2:25 into the video during charging? All I can guess is a plug of water being glugged through - but that is physically making the PV move!!

http://www.youtube.com/watch?v=UhnX5oF9o58


-CB

[fredrosse]

The relief valve needs its own connection, with nothing else on that line. The relief valve should be connected as short as possible to the PV. Definite rules for the setup.

The thumping you have going on is steam bubble being formed,then rapidly collapsing as the steam bubble is condensed by cooler water. As the water consumes the steam bubble (the steam condensed at the steam/water interface), the void space approaches zero volume,yet the water is traveling at a significant velocity as the bubble steam volume vanishes. Bang, what is commonly called waterhammer., and the PV jumps. Similar to cavitation, but on a much larger scale.

I would recommend the vent cock be opened far less than the video shows, and I would recommend a much smaller charging connection.

How high in charging pressure did this test go?

Seems like much steam leakage going on after you shut the cock, is that so?

[cyberbadger]

The relief valve needs its own connection, with nothing else on that line. The relief valve should be connected as short as possible to the PV. Definite rules for the setup.

I can move the safety to directly off the forged cross, but that's as close as I can get.

I would recommend the vent cock be opened far less than the video shows, and I would recommend a much smaller charging connection.

The charging was restricted to 1/4 sched 80 NPT, which is 0.302". It's that first fill that you have to be slower with. When the PV is hot it's not also acting as a condensor and was happier. The venting, well I was learning.

How high in charging pressure did this test go?

I did several fills up to and not exceeding 150PSI Boiler pressure and tested that the Aquatrol ASME 125PSI Set Valve operated correctly, which it did at 125PSI.

The PV didn't do the water hammer bouncing again.

Seems like much steam leakage going on after you shut the cock, is that so?

Yes. This was not the PV. That 1/4" braided ss hose occured previous physical damage and was leaking steam. It is junk, I will cut it in half so I don't use it again.

-CB

[cyberbadger]

So I believe that I would be better off not have ambient water inside the PV during heat soaking. Once the PV is a similar temperature to the boiler things are a lot smoother.

I actually ran the boiler for a while with the PV daisy changed. When the boiler doesn't exceed 125PSI this arrangement is stable. You can even charge the PV from 150psi from the boiler if you don't charge with the valve fully open and sneak up to ~120psi and shut the valve.

How do they handle similar things in the industry? From what I've seen with this any condensate in a large system (like a building) with 4" steam pipes is going to cause a fair bit of trouble.

I've also noticed that the PV size/shape make it ripe for oscillations. The most hilarious, I wanted to take a video - the PV was charging and it sounded like a man respirating/snoring. (Inhaling for 1-2 seconds, and the exhausting)

-CB

[cyberbadger]

2 The pin or key is missing. If the barrel retracts without needing to be re-aligned, this is the most likely.

2, That there is a smaller screw with a large washer in the end of the main screw shaft that acts as a stop and will not allow the main screw to exit the nut. This small screw is accessed though the end of the tail stock spindle, pull out the drill chuck and look inside with a flash light. If you see a threaded hole in the end of the main screw, this is where the stop bolt should be.

Thanks both of you. I found the set screw. Sometimes I wish machines had more helpful labeling. Like - hey dork make sure you check here...

-CB

Tip

lathequill.jpg (113.44 KiB) Viewed 10615 times

[Lionel Connell]

What were the final results of the original experiment?

[cyberbadger]

No final results.

My Pressure Vessel was tested under steam and it worked - the only steam test - the video of that trial is on this thread.

I have not made more progress, but a land based bicycle is the next thing I am going to try. Same Stuart 4A and the PV basically strapped to a bicycle.

Don't hold me to it, but I intend to try this within the next 3 months.

At a later date I intend to use the PV+Stuart 4a is the plan eventually for a fireless steam kayak. This seems harder to me then trying the bicycle concept first. The idea of a Fitch inspired Duck drive with wood linkages based on some scaled measurements that Fred already provided would be what I would like to build because it will be finicky and probably breakdown - and that is just fun in my book.

-CB