DetroiTug's Tug is going together

[artemis]

Den, I won't have to do that, I'll just run the Southworth vertical steampump that is also being added in the future.

-Ron

And don't forget a nice Penberthy injector! But for a duplex steam pump you might want to try a "Breisch" pump. Several boats in the PacNW using them as backup - and they look "neat" slowly moving back and forth and they . Castings are available from Myers Engines at: http://www.myersengines.com/. He also has a very nice steam boat of his own.

[fredrosse]

Back in the 1960's I worked for the US Army Corps of Engineers, Dredging Operations. When the dredge came upon something big in the channel, Derrick Barge No 29 was brought out, a spud barge with all reciprocating steam winches and cranes, to lift out the offending rock or sunken tug or whatever.

The barge had a scotch marine boiler, and the automatic boiler water level control was simply a duplex steam driven pump, with the steam connection right where the water level in the boiler was supposed to be. When the water level was low, the steam pump worked away, filling the boiler. When the boiler water level reached the pump's steam connection, the pump would choke up with water, and slow down to a very low rate. When the level went down again, the pump's steam cylinders would clear, and it would start pumping again. Simple, and reliable, worked that way for the 5 years I was working there.

[dhic001]

Hmmm, hadn't thought of that. Will water boil because it's simply being recirculated through a pump and bypass? I can see there being friction/heat created by the sliding surfaces within the pump, but the water would cool running through the tubing which would act as a radiator?? Or am I wrong in thinking that?

-Ron

Ron,
Most waterblaster pump recirculate back to the inlet of the pump when in bypass mode. I work on them in my day job, and believe me, i've seen a number of them badly cooked due to being left running on bypass. If I was trying to do what you want, I'd send the water being pumped all the way back to the hotwell. That way the pump is always getting fresh water through it. Sure there might be a little more plumbing, but do you want to find your backup pump doesn't work when you need it?

Daniel

[S. Weaver]

Back in the 1960's I worked for the US Army Corps of Engineers, Dredging Operations. When the dredge came upon something big in the channel, Derrick Barge No 29 was brought out, a spud barge with all reciprocating steam winches and cranes, to lift out the offending rock or sunken tug or whatever.

The barge had a scotch marine boiler, and the automatic boiler water level control was simply a duplex steam driven pump, with the steam connection right where the water level in the boiler was supposed to be. When the water level was low, the steam pump worked away, filling the boiler. When the boiler water level reached the pump's steam connection, the pump would choke up with water, and slow down to a very low rate. When the level went down again, the pump's steam cylinders would clear, and it would start pumping again. Simple, and reliable, worked that way for the 5 years I was working there.

Whoa, Fred. I remember James O'Donnell talking about that dredge when I worked for him as a shore engineer ...

[DetroiTug]

Ron,

I bought one of those Breisch pumps about five years ago and performed about 90% of the machining. I came to the conclusion it's actually a static model. It probably works for full scale apps, but those are some tiny fasteners for full scale service. Some were 2-48? If I remember correctly - which I upsized to 4-40. Then I hit two big air pockets in the main pump casting, that was the end of my interest. I may revisit that build someday.. Next steam pump will be a Southworth vertical.

Dan, Regarding a "waterblaster" I'm assuming that is what we refer to as a pressure washer? That is a much more demanding environment for a pump than our slow turning feedpump requirements. The pressure washers typically have an automatic bypass, when in bypass, there must be sufficient pressure (horsepower) to keep the bypass open. I could see that getting hot if ran very long. We manually open the bypass, depending on the restrictions in the piping, the horsepower requirements would be very low. But it is something to consider, I'll let you know how it goes when I try it.

As I was twisting together one 2-4 dollar fitting after another building this "system", I had an idea for an all in one piston pump. Easily accessible internal checks, internal bypass, ports for a relief valve and pressure gauge. Would be simple to get cast up and machine. Another project to tackle. Anything to do away with all that external piping.

-Ron

[Lopez Mike]

Fred,

Now I am fired up about finishing my Breisch pump that I mostly machined twenty years ago and set aside. My castings seem O.K. And I have built some very small piston steam pumps with good results providing that I was careful to get everything lined up. They do not like binding.

Ron,

I like that idea of feeding the pump from a point on the boiler. Particularly because my boiler has an unused fitting that is right at the half glass level. Frankly I hadn't thought that the pump would clear itself once water logged. My reservation is that it will be a bit of a steam hog as these simple pumps make little or no use of the expansive properties of the steam. Also, I will have to think about the volume of the piping between the boiler and the pump. A lot of water there to clear out on restart. Small diameter piping, I guess?

I have a Stuart #1 that needs finishing and I have been sketching a piston rod driven feed water pump for it. Sort of like a steeple compound arrangement. That way I can back off on the cutoff point of the engine and get lower steam consumption.

Too many projects!!

[DetroiTug]

Mike, It's the area of the steam piston in relation to the water piston. When the steam cylinder filled with water, the pump probably just slowed way down, but continued to pump. Continuing at a slow rate and cleared the water when the steam returned, the pump sped up. Pretty clever actually.

-Ron

[Lopez Mike]

I was thinking about the problems one gets into with liquids getting into a regular steam cylinder. Hydraulic lock and all that. I guess the reciprocating pump would just slowly pump the liquid on through at a much slower rate with no damage. It does seem as though it would be a good idea to limit the volume of the feed line from the boiler and have it well insulated to cut down on condensation.

[DetroiTug]

Mike,

I had to think about that one a bit at first. Sending water to an engine will lock it due to the timing and fixed stroke length. These pumps are full on/off timing at the end of the stroke. No crankshaft,eccentric that must complete a rotation - travel past top/bottom dead center etc .

-Ron

[boatbum]

Jim Crank talked about a boiler that had this type feed water pump. I'll see if I can find the info and repost it here.

Keith