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[ir3]

For the last few weeks I have been doing exhaustive searches about the use of Steam Condensers/Separators and have not been able to come to any strong conclusions about the size needed for a given Steam Engine. The exhaust on a steam engine is not different than the exhaust on any other types of engines that require an efficient exhaust gas flow. The goal of a efficient engine is to reduce back pressure from the exhaust system to a minimum or no back pressure at all.

This requires that the exhaust ports must be of sufficient size and the lines leading to the condenser/separator must be of sufficient size so guarantee that no back pressure is generated. Also, the size of the condenser and it's output port must be of sufficient size so that back pressure does not build up reducing the efficiency of the engine.

So, how does one go about determining the size of the condenser and the size of the lines going in and out. One must assume that the exhaust ports on the engine have been properly engineered for maximum efficiency. I believe there was a discussion somewhere on the site but I can't find it. It seems to me that when looking at the various condensers/separators that are available the input and output ports appear to be too small thus reducing the efficiency of the engine.

Hopefully a spirited discussion well help in determining the correct size of the condenser/separator for a given application.

Cheers,

IR3

[BarryM]

I would suggest you drop the "condenser" part of  the description. A condenser suggests cooling of the exhaust steam by a tube bank or similar circulated by a cooling medium. Our systems are simply oil separators placed in line to keep the decks clean. As such I don't see size as critical as long as it has sufficient capacity to store the anticipated condensate.
Barry M

[Jerry C]

You have a large number of variables to consider here. Length of run is determined by fuel supply and how you use it. The longer the run the larger the tank needed. Better lagging on the tank will reduce condensation in tank and so reduce size of tank. Hot weather, small tank, cold weather larger tank. Some peeps have an over flow to overside so tank never fills up but pipe arranged so oil never goes overside.  There must be no pressure drop across the tank for this to work. I have recently increased the bore of my steam discharge pipe from the separator (9" long) and this has considerably reduced the exhaust back pressure. I intend at the end of this season remaking the whole exhaust system in larger bore pipes. I use a Maccsteam 3 1/2" boiler with a gas tank that gives me between 50 minutes run in winter and 30 minutes run in summer. It drives a TVR1ABB and a 2 3/4" x 4 1/4" propeller. My separator holds 90 cc. And has proved adequate. I have a feed pump which maintains the level in the boiler.
Jerry.

[gondolier88]

Steam exhaust pipework is usually around twice diameter of steam supply pipework.


How large the separator is largely depends on how much water you expect the engine to make- if it is a thirsty oscillator running at low pressure (<30psi) then it will make quite a lot of condensate at startup and during running.


If you have a larger engine with true drain cocks, allowing you to warm the engine up on the shore and get it upto temp. before sailing it will send far less on startup to the separator, and once upto temp will make less when running.


Here's one I made a couple of years ago for someone on Canada, the engine makes quite a lot of condensate on startup, but being made from a block of brass, once it has warmed up it doesn't make too much. The separator doesn't get full before the gas tank runs out anyway!


Greg

[ir3]

Thanks for the input. I think I am now better prepared to install the Steam Separator.

Cheers,

Iran

[KNO3]

In my experience, the condenser/separator volume can be around 1/4 of the boiler volume to be large enough not to overfill during a boiler run. This is no hard rule, just my observation. What really helps with minimizing condensation is to build a superheater into the steam supply from boiler to engine.

It is also a good practice to make the exhaust pipe larger in diameter than the supply pipework. However no commercial maker that i know of does this. Most use 4 mm pipes for the supply and exhaust pipes of engines starting from as small as 2 cc (like a Cheddar Pintail) to 8 cc (like a Graham TVR1A).

In my case, I have used for 3 mm supply pipes 4 mm exhaust pipes. So roughly one size larger.

[ir3]

I think the problem is solved for the T2DR by using the Saito Condenser for this engine. It has 3 exhaust input ports to handle the two and three cylinder engines thus avoiding the two into one exhaust header. I am not much of a fabricator so I really need to depend on the commercially available items and the Saito condenser fits the bill exactly.

Thanks for the input.

IR3

[xrad]

My seperator is about 1/4 the boiler size as well. The exhaust headder is stock, and this empties into an exahust tube which is at least 2/3 wider diameter than inlet pipe(probably a bit more). The tank accumulator tank has a large drain on the bottom which hooks up to a syringe so I can easily empty it.  I can run about 30 minutes moderate-full steam before needing to empty(longer if less steam passing through). The tank will let me know when it is full because it is piped into the boiler chimney. At the bottom of the chimney is a good sized brass pot which catches the overflow before it spills out of the boiler frame. this steams up fairly actively when overflow occurs.
Also, I run the donkey pump and the site glass drain into this tank as well, so it can fill up fast...

You have seen the pics, but here is is again....

[xrad]

PS: I don;t recycle the water as the oil never really seperates in my condenser. I don't want oil/water into the boiler. I have another tank for fresh water.