Just a Progress Report

Hi Fish

This is looking really good, but what a big project, have you started on the building / cistern yet?

Sorry to hear of your incident, but much more is learned from a prototype when it is tested to destruction ;)

My thoughts on the pump are as follows;

First, where are the current pumps? (submersibles in the well?) I only ask because when a pump has a large head on the suction side, they can have trouble priming, and the better you have to seal it to make it self prime, the greater your friction losses.

I missed the double acting bit in your first post, this will be better than single acting, but in any case the flow rate will be highest at mid stroke and zero at dead centres. accelerating and then stopping the mass of water in the pump and pipework every stroke will eat into your efficiency.

An air over water pressure vessel, bladder tank, (whatever you want to call it) on the delivery side will help matters by smoothing the flow in the delivery pipe.
Something similar on the suction side, but with vacuum instead of pressure, MIGHT work.

If the head is not too high, a one way valve bypassing the pump MIGHT allow some water to continue flowing as the pump reaches the end of its stroke (similar to the scavenging that occurs during the valve overlap period of an IC engine) Although if this is going to occur, the pumps own valves should allow it providing they are not too heavily sprung (The valves should not really need springs at all, although some spring pressure does help priming)

Have you considered other types of pump?
A rotary vane pump, provides a smooth flow, and I would imagine is fairly efficient.
I would imagine that you have good reason for choosing a piston pump?

As Ghurd mentioned, 3 cylinders will give a smooth output (most pressure washer pumps for example are 3 cylinder single acting)

If you are set on the idea of a double acting pump, then 2 cylinders will do, with the crankpins at 90 degrees, OR if you have room make a 90 degree V twin, then you only need a single throw crankshaft ;)

Still on reciprocating pumps, have you considered a diaphragm, rather than a cylinder and piston?


Structures

Have you considered any auto parts? more specifically a fully floating rear axle from a twin rear wheel truck, if you get a whole axle (weld the diff up) and you have an (approx) 4:1, 90 deg bevel gear assembly.

Taper roller bearings can handle bigger loads than ball bearings (the downside is more friction) but I wouldn't have thought that hub would be a problem even if it is on ball bearings? if they don't last too well replace them with rollers, bearings are also made in several different quality grades, as well as "specials" for abnormal applications.

Copper is used for its malleability, ductility, and conductivity, but you knew that anyway ;) I'm not saying it's not strong enough, but a copper tube with thick enough walls for structural applications, would be uneconomical in terms of price and weight.

Soft solder, I can't find my old stuff, hence using some lead free stuff at the mo, it's rubbish, again not really a structural material.
Hard soldering (brazing and silver soldering) "CAN" produce a stronger joint on steel than welding
("CAN" does not mean it will)

Plastics, is a minefield of a subject, that there are many books on (and no doubt loads of info online)
no point me adding my tuppence worth, as there are so many types that you will need to look at the material you plan to use on it's merits, downfalls, and preferably some raw hard data too.
All I will say is please don't use PVC in contact with your drinking water. (check any others too)

Manufacturing Techniques

A pump body is by its very nature going to be mostly hollow, to machine it from solid would be expensive and wasteful of materials, a casting would be the usual solution.

You could either outscource the casting, or here is how I would go about

"getting the wife to let you play with fire"

Make her something nice, prepare the pattern in secret, a disposable welding gas cylinder makes a passable crucible if a bit small, A decent wood fire will easily melt aluminium without forced air, and cast it while she is out shopping.

Your profile says NC North Carolina ? Marianne, the girl I made the casting for used to live in Charlotte, but she is now in South Carolina, so you never know, one day I may be in your neck of the woods, IF they will even let me in to the US.

Regards

Peter

Woodsman,

Thanks for the reply!

About the pump/well/cistern. The well is a 45ft 1.25in metal casing with fabulous water. There is an existing 3/4hp electric pump connected to the well. There is a ~60ft horizontal run + 12ft vertical run from the well to where the wind driven pump will be. This run is 1.25in as well. The cistern is in place and functional as are the well pump and the high pressure pump:

Pump House: (Obviously still under construction :-) )


Well Pump: (With "rock removed" :-) )


High Pressure Pump:


The decision to use a piston style pump is based solely on the high torque // low RPM nature of the lenz style VAWT. I intend to connect the VAWT to a 5:1 speed reducer to further increase torque (and lower RPM). Ultimately even in a 15mph wind the VAWT RPM will only be 45 to 90 and the output shaft of the reducer will be 9 to 18 RPM. This is way too slow for a rotary vane style pump. I have not finalized the pump design yet; I have several thoughts, but I am certainly open to suggestions.

Piston type pumps typically maintain their prime, so I do not anticipate much trouble there. @ 15mph I will have about 1/4hp available, and about 1hp at 24mph, but I want the pump to "operate" at as little as .05hp (10mph winds). At the end of the day getting some water from the wind is a "bonus", I really want to make sure the wings fly when there is a breeze :-) , so the pump will be a bit smaller than it might otherwise be to avoid low wind speed stalling. (This is also the reason for the 5:1 gear reduction.

I have been spending some time thinking about how to "route" the water from the turbine. The options are 1) Filling the cistern (low pressure discharge), 2) Directly charging the water system (high pressure discharge) 3) Supplying the irrigation system (High Pressure discharge // dump load). I currently use two 55 gallon bladder type pressure tanks (which oddly enough DO NOT hold 55 gallons, but 36 gallons). My general thinking is to add two more of this type tank that will be isolated from the main system by a check valve preventing "back flow" into the turbine fed tanks from the main system pressure, so that the wind driven water can "feed" the main pressure system but the main system will not pressurize the turbine system. Use a "sprinkler control valve" to allow low pressure filling of the cistern. Use a pressure sensor to provide water to the irrigation system when there is no other demand and pressure reaches a "critical level. A simple uController should allow "intelligent" monitoring and control and a PC interface. I am planning on installing a marine "fuel sending unit" in the cistern to monitor the water level. We use ~100 to 150 gallons of water per day, so the 550 gallon cistern provides roughly 4 days of water volume with no draw from the well, allowing for fairly long, atypical, calm periods.

Have you considered any auto parts? more specifically a fully floating rear axle from a twin rear wheel truck, if you get a whole axle (weld the diff up) and you have an (approx) 4:1, 90 deg bevel gear assembly.

I have THOUGHT about a lot of things, I have yet to make a decision. I am now considering going to a few junk yards in search of a lamp post or light pole (steel or aluminum). I am thinking I might simply run a "smaller" rotating shaft inside a larger stationary shaft (the lamp post). A tapered roller bearing on the top of the lamp post, and 6 "small" ball bearings forming an adjustable "center" bearing that rides on the outside of the lamp post at the bottom of the turbine. I am sure that doesn't make any sense, I will draw it up and post a picture later on if I decided to go that route. But I have explored a lot of other ways as well. A truck axle has some merit, if I can source one cheap enough. I have also considered getting a "custom drive shaft company" to simply make me a shaft to my exact specifications, LOL.

Your profile says NC North Carolina ? Marianne, the girl I made the casting for used to live in Charlotte, but she is now in South Carolina, so you never know, one day I may be in your neck of the woods, IF they will even let me in to the US.

Holden Beach, NC. About as far South and East as you can get in NC and not be in SC or wet. Funny you are worried about getting in the US, seems to me more difficult to get out, LOL. I love the lower latitudes :-) If you do decide to hop across the pond, let me know and I will give you my contact info; you and Marianne can come stay with us for a couple days and enjoy the beach.

"getting the wife to let you play with fire"

Make her something nice, prepare the pattern in secret,

LOL, unless I do it in gold I doubt seriously that will have any positive impact. It is really not a question of her "letting" me do anything, we have been married for over 20 years, she gave up attempting to "give permission" a long time ago. It is simply a question of time. I have five fairly major construction projects going, a large number of "smaller" hobby projects going, several fairly major projects "on the board", and a very long list of minor projects that need finishing. Oh, and I own and operate a seasonal business that is open 90+ hours a week during "the season", which is almost here :-) So, even if she begged me to set up a blast furnace and cast something for her I doubt seriously I would get to it any time soon.

I really appreciate your input!

Fish