Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Hi Tore

An airvessel ( sometimes called windvessel) is only a " bulb" rigth after a pistonpump. It contains an air cushion which act like a buffer and equalizes the pressure fluctuations coming from a reciprocating machinery like a pistonpump. Nothing much, just a casted "blimp" migth be an airconnection on the top.

I have found the drawing of the cooling water pump for the G.W. diesel engine.


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Regards
Maciek

Exellent! Simon the bulb on the top is the airvessel.
Tore

[tore]

Hi Simon

Luboil checkvalves.
The footvalves at the luboilsuction is a checkvalve, the symbol is round, a 3way cock is square. Se drawing below.

The valve icon has three lines on it, so does this mean OFF/HALF/FULL?

This translation of the OPZ Ventil is not quite correct. In the Technisches Hilfsbuch f

[tore]

From the picture below I believe that valve E this right above valve F and the hand pump is port of the these two valves. I am not 100% sure where valve C is 

Tore, the small air lines which go to the 3-way valve (with the red handle) do you know which system this is? Is it the Oxygen system, Engine starting air system or the low pressure system?

Simon
I now realized I overlooked you question of the red handle, but I guess I answered same without refering to your question by my picture posted later. It is the pneumatic system for the main engine clutch.
Tore

[SnakeDoc]

Hi

Plate 14:  (Left) Engine lubricating oil system, (Right) lubricating oil storage, sump and purifying system, for Krupp engines

Q: Do you remember where the two pumps for cleaning are?

Lub oil puryfier pumps.
As far as I remember the suction- (dirty oil) and deliverypumps( clean oil) were intergrated in the puryfier as was the case of the heater. Unfortunately I don`t have a picture of the purifier but I`ll look for it and revert.

Tore, you remember well:


[quote author=U Bootskunde f

[SnakeDoc]

Some more informations are provided here:

[...]Filters, strainers, oil purifiers and oil coolers are similar to available U.S. commercial equipment. [...] The major differences from U.S. submarine practice are in the installation on the German vessels of a contaminated oil system, and the use of portable hose and interchangeable pipe connections to permit use of the hand and power driven detached pumps with fuel oil or other systems.
[...]
The forced lubrication system on the IX-C submarine is tied in with an oil purifying arrangement in a manner similar to U.S. submarine practice.  However, within both the lubrication and purifying systems, i.e: in tank design and in piping layouts, several basic and numerous minor differences exist.
[...]
The oil purifying system on the IX-C is of much lower capacity and is arranged to function in a somewhat different manner from the system as set up on U.S. submarines.  A single, standard DeLaval purifier, rated at 79.2 gals./hour is installed, while on U.S. vessels two 250-gals./hour purifiers are used.  The piping, pumps and heaters on the IX-C purifier system form an independent system and the units are selected with only that one service in mind, whereas the purifier pump and heater on U.S. vessels are of greater capacity than required for purification alone and are piped so as to be used also for transferring and heating oil from storage of sump tanks.  This dual service requires the installation of a "flow" regulating valve that isn't required with the IX-C arrangement.  A further difference exists in that the German purifier functions on a separator principle requiring a separate salt water feed line and salt water heater that need be kept in constant use and adjustment.  The Sharples purifier on U.S. vessels is presently used only as a clarifier and does not require a separate salt water feed line.  The German purifying arrangement with temperature and flow regulation on both the lub oil and salt water lines requires more attention during operation then on the U.S. setup with only temperature regulation on the lub oil line.

(http://uboatarchive.net/DesignStudiesTypeIXC.htm)


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Regards
Maciek

[SnakeDoc]

I have tried to look for a picture of the lubeoil separator (centrifuge) but sorry I didn`t find any. I think it was the Westfalia make.The only picture I got hold of was the present days Westfalia lubeoilseparators, allthough basically the same system it is not 100% the way it looked. Migth be somebody have a picture?

Lubricating Oil Separator
Number:   149  Type 2 LHD 2/20
Capacity:   300 litres lub. oil/hour at 1 atm. at a speed of 1350/1,750 r.p.m. (66 galls./hr. at 15 lb./sq. in.).
Makers:   Ramesohl and Schmidt, Westfalia, Oelde.
Motor Makers:    Werdohler Pumpenfabrik, Werdohl, I/W Paul Hillebrand G.M.B

(http://www.uboatarchive.net/U-570BritishReport.htm)


I have no exact picture or photo, but I imagine, the purifer can look like in this US patent issued for Ramesohl and Schmidt A.G. in 1929.
http://www.freepatentsonline.com/1734533.pdf


And to compare - the lubricating oil system on the US submarines:
http://www.maritime.org/fleetsub/diesel/chap7.htm#7B


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Regards
Maciek

[tore]

Maciek
Interesting text and true the VIICs lubeoilseparator was a purifier and not clarifier which means to Simons astonishment that it was hooked up to the sea coolingwatersystem for washing the oil. I see in the paper that the make of the sentrifuge was DeLaval, I guess you probably had different makes. As far as I remember the main difference in look between DeLaval and Westfalia was the bowl. DeLaval have a domeshaped bowl whereas Westfalia was more pyramideshaped, I think Simon need primarely the shape and pipeconnection as everything else is intergrated inside the separator. I guess I would go for the Westfalia.
Tore

[tore]

Lubeoil centrifuge.
A typical marine luboil centrifuge looks like on the posted picture, but again it is not excactly the one on a VIIC.
Tore

[SnakeDoc]

Tore

A typical marine luboil centrifuge looks like on the posted picture, but again it is not excactly the one on a VIIC.

Nice picture. I imagine that purifier on the type VIIC would like similar, except the driving motor would be mounted above the drum, with its shaft vertical, directly coupled with the rotating drum (and dirty and clean lubricating oil pumps).
I have noticed, that almost all the machines (main drain pump, trim pump in the control room, auxilary cooling water pump and auxilary lubricating oil pump in the diesel engine room, cooling water pump in the E-motor room) on the U-995 have such construction - vertical shaft driven by the electric motor mounted above. I think, that purpose was to better protection from water (besides the splash-proof or even water-proof cover).


--
Regards
Maciek

[tore]

Maciek that could very well be so, the problem would be you have lift the bowel up for cleaning and the water inlet would be on the top of the bowel see picture of the Westfalia purifier below.
Tore

[tore]

Maciek
Your remark that  in general the electric motor is placed vertically above machines particulary pumps, is of course correct and the reason you assumed, to prevent leakages down to the motor is rigth. However there are exceptions as for the aux. lubeoilpump, where the pump and motor are mounted horizontally on a common bedplate. The present days Westfalia lubeoil purifier has the motor horizontally and the purifier vertically mounted on a common bedplate. I simply cannot remember the execution of the VIIC purifier, if it was fitted for space reason vertically, I would imagine the emotor had to be underneath which is as you pointed out a bad solution, but not impossible, but I`ll give the present days Westfalia execution a 65% chance. Let`s see if somebody can dig up a correct picture
Tore 

[SnakeDoc]

Hi Tore

Your remark that  in general the electric motor is placed vertically above machines particulary pumps, is of course correct and the reason you assumed, to prevent leakages down to the motor is rigth. However there are exceptions as for the aux. lubeoilpump, where the pump and motor are mounted horizontally on a common bedplate.

Do you mean this pump?

(u-historia.com)


I have also noticed, that this pump is different. But:
[quote author="U Bootskunde f

[TopherVIIC]

Generally speaking, any rotating machine resting on a single set of bearings will be more quiet than the same machine resting horizontally on two or more bearing races... Perhaps the vertical design was to aid in silent running?

[tore]

Maciek
You are absolutely rigth and the horizontal pump has nothing to do with aux. luboilpump. I was too quick in getting my mail posted before my internet connection was cut so I didn`t check properly. Sorry it is all wrong from my side.
So what is this horisontal centrifugalpump doing? It is not included in  any luboil-, fuelsystem as well as seacoolingwatersystem. If you look at the electric connectionbox it is not the normal german wartime type, I believe they were square, it looks more like a norwegian type of box after the war. The valve wheel is the shape of the potable freshwatersystem and there is a filter on the suction side. My guess is that the pump has been installed after my time by somebody who got tired of pumping freshwater by hand.Both the freshwatertank and the users are rigth behind the forward bulkhead. What do you think?
Tore

[tore]

Christopher.
Interesting aspect. I wasn`t aware of that, but it sounds convincing. There were a number of other machineries horizontally mounted, most of the essentials were on resilent mountings, you can see both vertical and horisontal execution on the picture below. By the way the mysterious pump mentioned above is on resilent mountings as well.
 Tore