hand pumps

[johnp]

How do i know what size hand pump i should use fro refilling my boiler?

[Lopez Mike]

Personally, I don't use it that much but when I do, I'm in a state of anxiety and want it as large as I can handle. But if it is too large, the handle gets long and in the way.

Mike

[farmerden]

The handpump on the "Steam Queen" is pitifully small-I'm sure it moves a teaspoon a stroke!.When the water in the site glass disappears it takes forever to get it back! Probably the water level is right there but----- Beckman offers a large handpump which I have for the other boat.Obviously he follows the same theory as me "What will do more will do less" You can't get the water back fast enough as far as I'm concerned. Den
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[barts]

How do i know what size hand pump i should use fro refilling my boiler?

You're limited by your arm strength, piston diameter and boiler psi.

You need to be able to force water into the boiler at maximum PSI. I find a piece of 1/2" brass pipe and a chunk of 5/8" stainless for a rod work pretty well; on my boat that's 55 lbs of force; my lever gives about 2:1 so 27 lbs or so of effort; that's prob. enough for most folks since it is pretty repetitive. Stroke is limited by handle length ...

- Bart

[fredrosse]

The pump should have all wetted parts of corrosion resisting materials, brass & bronze, or stainless as Bart recommends. It is recommended that the water circuit from the water source (tank, lake, etc) to the pump also be corrosion resisting materials, automotive radiator hose is what I use, with a strainer just before the pump suctions. This will minimize pump trouble with hung-up check valves, etc. The discharge piping can be any pipe suitable for the temperature/pressure, common steel would be good.

The manual feedwater pump for the Margaret S. was made from standard brass pipe nipples and standard brass screwed fittings. It is fairly large, with the pump cylinder of 1-1/4 inch pipe, and the inlet/outlet check valves are standard 1/2 inch swing check valves. Although rather large, (200 PPH water flow at 15 strokes per minute) it has given good service so far, and was built in less than a day, due to using only standard screwed pipe fittings. A short piece of 1-1/2 inch boiler tube forms the manual handle, and it works with reasonable effort at about 85 PSI in the boiler. If I pump to higher boiler pressure I would make a wood extension handle to insert into the 1-1/2 inch tube handle.

A brass plate is silver soldered onto the suction/discharge head for mounting to the steel frame that has the hand lever attached, alternately the pump barrel could have been simply attached to the frame with ordinary "U" bolts. The connecting rods are 1" x 3/16 inch flat bars, and the pivots are simple hardware store shaft collars welded to the flat bars, or ordinary steel nuts & bolts used as pivots. These parts are not detailed on the attached sketch, which shows only to basic pump cylinder / piston & Check valve arrangement.

The only lathe machining required was to cut down a brass reducing bushing to 1.35 inch OD, and machine two grooves on the piston to accept standard O-Rings. The store bought brass pipe nipple that makes up the pump cylinder has a finish that is good enough for pump duty with no further work. Making everything else was with a hacksaw, a common portable drill, and some MIG welding.

[87gn@tahoe]

I figure I should put out a word of caution about using brass in a marine environment, especially where dissimilar metals are in direct contact and there is chance for electrolysis, especially true in salt water.

The brass can suffer from dezincification. It is a process in which is the zinc in the brass is leached out, causing it to loose it's structural integrity. Not a good thing if you're relying on it for holding boiler pressure, or even the pressure of the sea on the hull.

Bronze is the only way to go in a marine environment. Of course, don't use bronze alloys with any significant amount of zinc, like manganese bronze.

[Lopez Mike]

I agree that using brass in a salt water environment is a bad idea for the reasons that Wes lays out.

That said, the conductivity of our boiler water is remarkably low. We are, in essence, running a big old distillation plant.

I've experienced both extremes. I had a lower rudder bearing that was purportedly cast of bronze (hah!) , turn to something resembling hardened peanut butter over the years. On the other hand, I have some brass pipe fittings in the salt water path to my sailboat engine that have been there since 1971 and are still hanging in there.

It all depends on the electrical paths involved. I would worry more about the mechanical strength of brass v.s. bronze in a situation where I might stomp on the things with my big feet. The threads are sharp edged and are in invitation to failure at that point. That's why we use schedule 80 pipe coming out of our boilers. Schedule 20 would handle the pressure. We'd just bust it off.

Mike

[barts]

Brass works fine in our small (trailered) boats above the water line - of course, don't use it where it is in anything but incidental
contact with salt water. If the boiler feed pump is in contact with salt water on a constant basis, you have more critical issues than dezincification.

The Otter sees saltwater pretty regularly, sometimes for weeks at a time when we're in the San Juan Islands.

- Bart