Gear pump standard?

[hobgobbln]

has anyone suggested a simple flex shaft?

https://www.mcmaster.com/flexible-shaft ... le-shafts/

Never knew they existed until now. Those could be handy

Griz

[liveaboard]

What is the life expectancy of this installation?
Are we talking weeks, months, years, decades?

With the weather and salt exposure, it all makes a big difference.

If it's more than a couple of years, there will need to be a maintenance schedule for the float and ground tackle as well as the moving parts.
The shaft seal is a likely point of failure.

[hobgobbln]

They didn’t specify but I’d assume as long as possible. That’s why I was looking for either a mount standard or a super common pump and keeping it out of the water if I can. They also specified it needed to be serviceable so I need to have it be at least semi modular.

Griz

[liveaboard]

Hydraulic pumps are assembled for specific applications; so if you want a really common pump / motor, your best bet would be ones made for the most common machine around.

Garden tractors come to mind. Maybe someone has another idea?

Still, I'd just order whatever pump / motor you can get from a big supplier. It has a number and can be replaced.
You could also set the hydraulics on adaptor plates. Then the plate could be reworked or replaced as required if someone wants to repair the thing 40 or 50 years from now.

The bird would be a mechanical miracle if it lasts that long.
If it flaps 20 times a minute for 10 years... I get 105 million cycles.

I have a pump from my tractor with 10,000 hours on it that still works just fine. Those are 1,000+ rpm hours.

You definitely need to keep the pump out of the water, and the hose ends too (although you can get stainless fittings if you specify them).

If the submerged well / hull with the shaft and pump takes in water, will anyone know before serious damage occurs?
Rain water has a habit of creeping in, and during storms it's likely that waves and spray will wash across the platform. sunlight will blister and destroy coatings.

Idea; float with a vertical rod that would lift a flag or something. So if the underwater part started to fill up, it would be known without having to take a boat out to the platform and open the cover. A fairly finicky thing to make in a way that will still work after decades in the weather, but you can do it.

You could add a bilge pump, but a mechanical one that turns all the time will wear out in a few years (at best).
12VDC electric ones with float switch are very reliable, if you have 12VDC.

[liveaboard]

Each manufacturer has their own number system, but the defacto cross reference standard is the Bosch / Rexroth number.

[hobgobbln]

The bird would be a mechanical miracle if it lasts that long. If it flaps 20 times a minute for 10 years... I get 105 million cycles.

If the submerged well / hull with the shaft and pump takes in water, will anyone know before serious damage occurs?

Yes it would. I need to talk to the one making the bird before they start. I’m going to specify the wings to be removable and have replaceable pivots/bushings/axles/bearings, etc. In reality the bird isn’t my problem, but I want to make this as simple and maintainable as possible.

I’m hoping someone will notice but I don’t know exactly how it’s all going to work. The floating platform is supposed to be 45’x120’ (ish) and part of some nature trail type thing. It’s open to the public and it will have a bunch of other things on it, but I don’t think there will be anyone who actually works there everyday like a park ranger or attendant. Looks more like there will be informational plaques in front of things like a museum but I could be wrong.

For the sake of testing I’m going to try and find an old outboard engine to use the lower end. For the final shipped version I was thinking I’d build the shafts and new housing out of 316 stainless and use ceramic bearings to minimize corrosion concerns. From what I’ve been reading that would be the smartest way because of the salinity.

Griz

[Harold_V]

Keep in mind that stainless and chlorides don't necessarily play well together.

You may be better served to consider bronze. Some research might be wise.

H

[hobgobbln]

I will do that.

[Harold_V]

Monel and titanium are excellent choices for seawater.

H

[Bob D.]

Monel is common for boat prop shafts and Cutless bearings are bronze, lubricated and cooled by the water. Sacrificial zinc anodes for corrosion protection. If there is no electrical power involved aboard you will be way ahead on corrosion issues.

[hobgobbln]

Monel and titanium are excellent choices for seawater.

I’ll keep those in mind once I get further along.

I’m starting to think the salinity will be minimal but I’d rather play it safe and plan for it. There’s something called a “salt line” with tidal rivers. From what I can tell, it’s the point where fresh and salt water meet and looking at a map this will be upstream from it. I’m still waiting to hear back from the water guy about how to interpret the flow measurements they gave me but I’ll ask about the salt content too.

If there is no electrical power involved aboard you will be way ahead on corrosion issues.

There will be solar for some things if I remember right. Considering the size of this platform and the “I don’t even want to know how much they’re spending on all this” of the project, I would imagine they’ll have something in place like an anode already? That’s the architect’s issue though. I have enough of my own right now hahaha

Griz

[Bob D.]

So I live in Maine where a 10ft ocean tide is normal. I was trying to figure out where PA had any tidal action……. I guess the only game in town would be Philadelphia/ Delaware River area.