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restoring a Monotype compressed air dryer tank

Started by John Cornelisse, July 16, 2015, 06:31:55 PM

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John Cornelisse

A Monotype installation is not complete when there's no possibility to remove the water from the compressed air.

Air does contain moisture and compressing it will cause this moisture to condensate. All that water will eventually cause the typecaster machine to rust.

Monotype did use special airtanks to dry the compressed air. They came in two sizes. An example of the smaller version is present in my own atelier.

Each week - when in regular function - the water should be blown out. But this was not possible at all anymore. Some white emulsion of oil and water however was slowly leaking out.

So the tank needed "some" extra attention:

First all the emulsion needed to be removed. There are two exhaust-pipes actually,

The left pipe is connected to the inlet of the air, the right exhaust with the bottom of the air-tank.

But the last was blocked completely, and the emulsion was soaked from the tank with a long thin metal pipe that could reach all along the bottom. After taking away a small valve at the top of the tank, the pipe could enter, with tape around the pipe the hole was sealed and the compressor could be turned on.

After a day work a bucket of 10 liter emulsion was gathered. It was possible again to drain both exhaust-pipes. But than they blocked again.

After this we took the whole tank out of the atelier, after removing as much water from the outer tank as possible.


Now we needed to dismantle this tank completely. On top of the outer tank, there are lots of screws, all needed to be taken away.


On the next picture the spiral can be seen from above:


The spiral is attached at the top of the tank, after taking away three screws the spiral could be taken away:


After this the spiral was cleaned with a high pressure water cleaner. The tank was taken from the outer tank, rusting everywhere it was in contact with the water in the outer tank.


The outer tank was of course rusting anywhere too. All this rust needed to be taken away.






The outer tank and the air-tank have been cleaned and painted with lead-menie twice already.

John Cornelisse

I found a paper with construction design of the air tank, this I would like to share with you all.

In the mean time the tank has been painted with lead-menie some three times,
after this I will add a layer of zinc paint to give it it's normal appearance back. And
of course adding an extra protective layer of paint.


Within a day or so the airtank can be fully restored and it sure will be taken in action soon.

John Cornelisse

Adding zinc paint on the air tank, after 3 layers of red lead.


The water tank that surrounds the air tank, is also zinc painted inside, but here the bottom of the
tank was still not dry after a whole day, because there was too tick a layer of red lead. (lood menie in Dutch)

We will need to wait a little, after we took away the access red lead paint, with some sheets of paper.

On top of this we - Krzysztof from the BookArtMuseum in Lodz & I - we will add a tap at the bottom of
the tank, after that it would be a lot more easy to empty the watertank, whenever needed.

John Cornelisse

The outer tank will be added a little modification: at the bottom of it, a drain will made,
so that we will be able to empty the tank more easily.

This we cannot do ourselves, and the tank is taken away to the atelier of a friend
of ours. His hobby is to restore antique English made motorcars. He can sure do it.
When this will be finished we do not know yet.

But in the mean time we wanted to try out the pressure-tank. The fact that there
is no cooling water, will not damage it or hamper its function.

Here some photgraphs of putting it together, and getting it on its place.




For this moment we are able to cast again, some small amounts of character.

John Cornelisse

Casting some character went alright, with of course all the usual problems.

One mould with a number 100xxx, that should be a constant height mould although
it lacks the plate on the box - that gave splashes every time.

This information comes from the very man that still cast at the Type-archyve:
(almost 90 years of age !!! I'm told) Gerry Drayton

I need to investigate this... On the box: .987... should be Dutch height... The matrices
however do not seal mould the mould enough.... sealed.

This mould is there for some time, no need to take it in action before...



I made  a little table to place the whole tank on when the outer tank will return. There
will be a tap, that will make it more easy to empty the tank when ever needed.

This little table is made with some plywood and four little legs, that were left from a
disposed piece of furniture to store cd's.


John Cornelisse

This very day we got the outer tank back. A friend of us had made an extra exhaust pipe at the bottom of the tank.
A tap-crane was added too, and now it is a lot more easy to get the outer tank empty, when needed.


The tank was painted with lead and after drying with zinc-spray. After this we could not wait to rebuilt the machine again. The ultamate test was taken too. Now the water is clean, very clean.


job done. and it feels great.

Keri Szafir

I've been working with John on this very tank, it was frustrated, but fun...
When I opened the draining valve, NOTHING wanted to come through. It looked like the original tube to the bottom of the tank was clogged, and cleaning it from the inside with a copper wire didn't help either. It may have been some solid particles gathering in an elbow down below.
We tried a different approach: running an aluminum tube (with some rubber hose attached to it) to the bottom of the tank, then blowing the condensation out after turning the compressor on. It barely worked. Sometimes a liquid came through; sometimes we got some thick white goo. There was so much condensation that it separated into greasy and watery phases. We tried dissolving that with petrol or even sodium hydroxide, but it didn't work very well.
After some more hours of draining the tank with the aluminum tube, all goo went out... It was at least 20 liters.
We decided to take a look at the condensation tube, so we removed most water from the sleeve, took the whole tank out and dismantled it, then cleaned it.
We also came up with an idea to add a water drain tap at the bottom of the sleeve for easy draining. I don't know why the Monotype engineers didn't think about it... So, John had his friend Joop come by and take the sleeve to his workshop, where he could weld a fitting. After the sleeve was back, John painted it, as well as the tank, and we put it together after a few days. Works nicely now :).
"Any sufficiently advanced technology is indistinguishable from magic." --Arthur C. Clarke
"A thing of beauty is a joy for ever." --John Keats
Founder and owner of Keritech Electronics

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