Tores mailbox VIIC and VIIC/41 operation and technical details

[SnakeDoc]

Hi Don,

How about this for a proposal of the entire system...

Where the compressor exhaust duct penetrates the pressure hull?


--
Regards
Maciek

[Don Prince]

Hello Maciek,


Where does the exhaust pipe penetrate the pressure hull...  Hmmmm! I thought that you or Mr. Tore would be the better person to answer that question.  I would think it would be somewhere near the back side of the Junkers compressor close to the water trap.  I sure hope it wasn't at the location of what is now the entrance door. The short answer is "I Don't Know"... 


I just uploaded a corrected version of Skizzenbuch into my Dropbox folder...


Page 98 - Internal Exhaust Valve = Internal Exhaust Grinding Plate Valve
                External Exhaust Valve = External Exhaust Flap Valve


Page 438 corrected, My fault I circled the wrong valve...  Now I identified both valves.


Regards,
Don_

[SnakeDoc]

Hi Don,

Where does the exhaust pipe penetrate the pressure hull...  Hmmmm! I thought that you or Mr. Tore would be the better person to answer that question.  I would think it would be somewhere near the back side of the Junkers compressor close to the water trap.  I sure hope it wasn't at the location of what is now the entrance door. The short answer is "I Don't Know"... 

It was a bit tricky question.  I'm pretty sure that exhaust duct was connected to the upper part of the inner valve casing (similarly as on attached photo from U 570 - marked with red dots).
There is no reason to make another opening in pressure hull (which of course also has to be protected with hull valve - most likely also water cooled).


--
Regards
Maciek

[Don Prince]

Hi Maciek,


The approach to the junkers exhaust exit looks to be much simpler in the Type IX C built 7.8.43,  They have a selector valve that dumps any water from the exhaust pipe to the bilge...  There is no water separator, and the internal exhaust goes to the internal exhaust valve casing, but nothing is shown at the exterion of the pressure hull...


Regards,
Don_

[SnakeDoc]

Hi Don,

The approach to the junkers exhaust exit looks to be much simpler in the Type IX C built 7.8.43,  They have a selector valve that dumps any water from the exhaust pipe to the bilge...  There is no water separator, and the internal exhaust goes to the internal exhaust valve casing, but nothing is shown at the exterion of the pressure hull...

This diagram shows only that valve casing is water-cooled. The piping does not drain the exhaust valve. The f₂ selector valve is primarily used for injecting anti-corrosion agent into compressor cooling system and secondarily for draining the cooling system.


--
Regards
Maciek

[Don Prince]

Hello Mr. Tore and Maciek,

The exhaust separator on U-995 looks a little more advanced than the one on U-570.  U-570's separator looks to be positioned higher, but it looks like U-995's separator had a pressurized drain system... I believe there are two drain pipes at the top of U-995's separator.


There may be a sight glass and a valve cut-off on the upper drains, or some type of a float valve inside the separator because they don't want exhaust fumes going to the bilge and then throughout the pressure hull...


What do you think?


Regards,
Don_

[Don Prince]

After seeing this image from SUBSIM, It looks like the separators on U-570 and U-995 ate at the same height.


...and, Maciek notice there are two (2) tanks below the Junkers compressor.


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


I hope all has gone well with you and your wife moving to your country home.  I myself would not have the will or stamina to take care of two homes and maintain the grounds.  Do you have someone to stay in either home while you are in the other one? I would think that your country home in the winter may have water pipes freezing unless the hearing is maintained at a decent level in the home. Although, being in a country home during the Spring and Summer is a welcome way to relax and enjoy life. However, my wife Maureen is from the over crowed city of Jakarta, Indonesia, 10 million people and growing and she does not like to live in the country. Before moving to Georgia, we lived just outside of Lexington, South Carolina, with a population of about 20,000 people; she called it the village! Now, we live about 30 miles north of Atlanta, Georgia, where the congestion is creeping north ever so slowly...


I have updated Skizzenbuch with the latest info from Maciek, and added a colored cover and trailer page like many hardbound books. Sometimes it's not expansive to go first class...


Kind regards,
Don_

[SnakeDoc]

Hi Don,

The exhaust separator on U-995 looks a little more advanced than the one on U-570.  U-570's separator looks to be positioned higher, but it looks like U-995's separator had a pressurized drain system... I believe there are two drain pipes at the top of U-995's separator.


There may be a sight glass and a valve cut-off on the upper drains, or some type of a float valve inside the separator because they don't want exhaust fumes going to the bilge and then throughout the pressure hull...

On the photos from U 570 you are considering water separator of the Junkers exhaust system, while on the photos from U 995 there is another separator: at the output of the air compressors.

--
Regards
Maciek

[SnakeDoc]

...and, Maciek notice there are two (2) tanks below the Junkers compressor.

You are right Don, there are two flasks under Junkers compressor. Maybe these are flasks with starting air?

--
Regards
Maciek

[Don Prince]

Hi Maciek,


Perhaps one (1) is the oxygen tank in the aft torpedo room that we could not find?


Regards,
Don_

[tore]

Hi Don, Maciek and all others.
I am finally back on the net after an eventful openening of my summerfarm. Putting an old  farm in the freezer for the winter require precautions and a lot of actions based on years experience.The trouble being an old man however is  your require some help to do the job and with helpful grandchildren, we thought we managed last year.Unforntunately not so, and we had a few frostbursted pipes, iceblockage of the water main supplypipe and quite a few other things as well, however now it seems everything is back to normal and we are on the net, touch wood! I see there are still a number of questions and I shall try attend as soon as possible. I guess the  starting air vessel for the Junker is as on my image below. The oxygenflask at the bottom stb boardside is found and as far as I know the Junker exhaustpipe and internal valve is removed due to the accessdoor made in the pressurehull of U 995. The further arrangement have to be guesswork and I shall revert with some proposals in a while.
Tore

[Don Prince]

Hello Mr. Tore,


Glad to see you're back online...  You answered a lot of my questions about the country farm home, and I guess all the preparations my men and mice can not foresee all the obstacles created by mother nature.  It's great to have help from your grandsons...


Regards,
Don_

[tore]

Don.
As far as I can see the Junker exhaustsystem has been of considerable consern and changes since it was introduced. The two stroke, opposed piston engine was susceptible to exhaustgas counter pressure and carbonisation due to the ballancing of the free pistons and I guess there are a number of executions as the developement occurred. Again we don`t have much drawings available thus we have to assume some of the solutions based on photografic images. Below is my proposal of the plain exhaustsystem were cooling piping and casing are omitted as well as the intricate interlocks and the grindingsystem. To prevent waterintrusion in the Junker through the scavenging ports which are open in the starting position is of course of paramount importance, hence the watertrap and drainage is placed at the lowest point just before the Junker. The starting procedure would be as follows: The opposed pistons are cranked in the outer starting position, the stern buoyancytank vent is shut, allowing the outer exhaustvalve to be opened, however prior to opening the valve, LP air is admitted to the space between the inner and outer shut exhaustvalves. When opening the outer exhaustvalve the airpressure is forcing the possible water into the silencer and overboard whereupon the inner exhaustvalve is opened, and possible residue water is drained at the waterseparator and the Junker can be started. I guess the extra exhaustvalve after the boardvalve on the old plan would not be nessecary with the assumed U 995 execution. Unfortunately both the boardvalve,drainage, watertrap and most of the exhaustpiping is removed on the U 995 presumeably to make visitors access through the door in the pressurehull .
Tore

[Don Prince]

Hello Mr. Tore,


Is the aft buoyancy tank venting hand-wheel located on the upper pressure hull (between the 6th and 7th frame port side) in back and above the e-compressor.  I don't see how the lever with the interlock segment connects to the aft buoyancy tank or the hand-wheel?


Maciek had provided an image that showed the aft buoyancy venting valve hand-wheel located between the 6th and 7th frame, and the hand-wheel for blowing the aft buoyancy tank with LP air located between the 7th and 8th frame.


I also noticed there is a step in back of the e-compressor for the crewman to reach these valve hand-wheels.


Regards,
Don_