MYSTERY OBJECTS

[chinatyke]

Looks like a valve set at the bottom of a water gauge on a steam boiler.

[Stanley]

Dead right! It's lifted from the Dewrance catalogue online. Now for the question.... The try-cock at the bottom is described as 'asbestos packed', Hopkinson's were exactly the same. The question is what exactly does this mean? It's very esoteric and I'll not let it run too long if the answer isn't forthcoming. The main reason for raising it is that it's an obsolete technology, in fact it's illegal now but getting it on the web might solve a problem for someone somewhere who is looking for a solution to the problem of renewing the packing in an old valve. If you don't know the answer it can be a puzzle.

[Gloria]

Is it to stop it getting too hot and distorting.

[plaques]

Asbestos string was widely used as a packing medium. Being heat resistant it was used on different types of valves including steam valves. Old cars and motorcycles used it on push rod tubes and other oil fittings. That's why they were well known for dripping oil all over the place.

[Stanley]

Both on the right track but this form of asbestos packing was as far as I know, unique to these valves which were frequently used and needed to be steam and water tight. I'll give it another day....

[David Whipp]

Was the asbestos used in the valve seat? (If that's the right term?)

[Whyperion]

Valve packed while hot / heated so expanded , in normal temperature the valve would slightly decrease in size giving a nice tight packing ?

[Stanley]

Again, both on the right track but not what I was after. It's too esoteric so I shall tell you. One of the big problems with a conical cock on a water gauge on a boiler is that as it is used so often it is prone to leakage. Hopkinsons were the first I think, and Dewrance soon followed, to use indurated asbestos to form the seal instead of relying solely on the fit of the brass cock. They cut channels in the side of the conical seating and the packing was formed by ramming finely divided asbestos and rubber into the channels using a shaped packing tool struck by a hammer to get it tight. This was done with the plug in place in the seating and then the cock was re-assembled. As soon as the cock got hot in use the indurated packing was vulcanised by the heat, expanded slightly and formed a perfect seal. These 'asbestos packed' try valves remained steam and water tight much longer than a new cock and were unaffected by wear on the plug as it was the asbestos inserts that were making the seal, not the brass. Anyone trying to re-pack one of these valves today is in trouble because the proper packing is unobtainable now.
Sorry it was so complex but if someone who is trying to pack a valve like this they now have a clue, make their own indurated asbestos by incorporating materials that will set when heated. You won't be surprised to know I have some in the shed......

[David Whipp]

Stanley!

[David Whipp]

Not the leaves or the stones.

[plaques]

This is obviously an adaptation of Red Adair's Oil well blow off valve configured for Barlick gas leaks. If it explodes the stone will fly outwards braking a window and thereby allerting the authorities to the problem.

[Gloria]

Is it leakage from the treacle mines in deepest Barlick.

[David Whipp]

Gloria has it, you can just see the gas bubbling up.

I like Plaques' description, but too much drama.

[David Whipp]

[plaques]

Using my Clarke Kent X-ray vision. Its a manhole cover under a layer of tarmac. So why are manholes round? etc:etc.

[Whyperion]

If you have square or round inspection chamber (or coal hole ) covers it is possible to mis-align them across the diagonal (actually not even a full corner to corner diagonal dependent on the overall sizes ) and , dependent on the inner step measurements , if they tilt one loses the lid down the hole. On a circular hole the cover I dont think is capable of doing that as particulary the cover diameter is marginally larger than the hole diameter and , unless you fold the ground , the cover wont fall through as the widest diameter (ok the diameter is the widest chord across a circle ) of cover is larger than the widest diameter of the hole. Additionally there are material savings in making circles rather than squares , etc. I think the wedge trick also applies to things shaped like 50pence coins.

[plaques]

This was the answer given by Richard Feynman in his book. So who am I to argue?

Feynman: Not likely. Square covers are sometimes used on prefabricated vaults where the access passage is also square. The cover is larger than the passage, and sits on a ledge that supports it along the entire perimeter. The covers are usually made of solid metal and are very heavy. Let's assume a two-foot square opening and a ledge width of 1-1/2 inches. In order to get it to fall in, you would have to lift one side of the cover, then rotate it 30 degrees so that the cover would clear the ledge, and then tilt the cover up nearly 45 degrees from horizontal before the center of gravity would shift enough for it to fall in. Yes, it's possible, but very unlikely. The people authorized to open manhole covers could easily be trained to do it safely. Applying common engineering sense, the shape of a manhole cover is entirely determined by the shape of the opening it is intended to cover.

[plaques]

Something to be going on with.

[Stanley]

Is whatever it is sat on a mirror?
I'm all in favour of round manhole covers that can't fall in the hole having spent a miserable two hours at Ellenroad once after my lads dropped an enormously heavy sewer cover down the hole. Not recommended!

[David Whipp]

Using my Clarke Kent X-ray vision. Its a manhole cover under a layer of tarmac.

Sorry, not correct. Please carry on guessing.

[David Whipp]

Is whatever it is sat on a mirror?

I don't think it is Stanley, the full and empty circular thingies don't match up. Must be two lines of them.

Are the edges of the 'reels' toothed?

[PanBiker]

Is it a piece of some form of combine harvester for separating grain from husk or something like that?

[Stanley]

The circular item. Is it where the pad on the end of the stabiliser on the wagon bucket has bitten into the tarmac?

[David Whipp]

The circular item. Is it where the pad on the end of the stabiliser on the wagon bucket has bitten into the tarmac?

Good thinking, Stanley, but no.

[plaques]

David, I think between us we've got them guessing.

Is yours anything to do with Stephen King and aliens? Barlick is just the place for this type of "Mumbo Jumbo".