Author Topic: Report KD 634 about water pumping available  (Read 1124 times)

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Adriaan Kragten

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Report KD 634 about water pumping available
« on: June 30, 2017, 05:29:05 AM »
My new report KD 634 can be copied for free from my website: www.kdwindturbines.nl. The title of this report is: "Calculations executed for the 3-bladed rotor of the VIRYA-3.4 windmill (lambda design = 4.5, galvanised steel blades) driving a centrifugal pump through a Polycord transmission with i = 2.5 and a vertical shaft in the tower centre".

The VIRYA-3.4 windmill is designed to drive a centrifugal pump using a Polycord transmission with a round string and an accelerating gear ratio i = 2.5 in the windmill head and a vertical shaft in the tower. The main advantages of this transmission are that it bridges the eccentricity in between the rotor shaft and the vertical shaft and that it contains no oil which may leak into the water. The windmill can therefore be used in nature areas. A centrifugal pump can be coupled directly to the vertical shaft or one can use a second accelerating transmission at ground level. It is also possible to connect a generator in stead of a pump to the vertical shaft and even a pump plus generator seems possible.

More information about water pumping with a windmill is given in my free public report KD 490.

george65

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Re: Report KD 634 about water pumping available
« Reply #1 on: June 30, 2017, 09:22:04 PM »
The title of this report is: "Calculations executed for the 3-bladed rotor of the VIRYA-3.4 windmill (lambda design = 4.5, galvanised steel blades) driving a centrifugal pump through a Polycord transmission with i = 2.5 and a vertical shaft in the tower centre".

That's going to be one hell of a title to fit on the front cover of a book if you ever decide to publish it!   ;D

Then again, " Free Public report KD634"  while much shorter may not do a lot for demand either!

What is the purpose of these papers you produce? Do you submit them for study at a university, have to show something for research funding, do them for fun ( !!) or is there some other motivation?

Adriaan Kragten

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Re: Report KD 634 about water pumping available
« Reply #2 on: July 01, 2017, 03:00:02 AM »
The titles of my reports are made that long to make that only reading of the title gives a detailed impression about the content of the report. I have written more than 600 KD-reports since I have started my own engineering office Kragten Design in 1989 and more than 60 KD-reports are made public now. A list with all public KD-reports is given on my website at the top of the menu KD-reports. Below this list, the folder "Sequence KD-reports for self study" is given. Writing reports has become a habit from the period 1975 -1990 when I was working for the Wind Energy Group of the University of Technology Eindhoven as every guilder we got from the gouvernment had to be justified in public reports. But most of those reports are not made digital and are therefore no longer available. 

When I started my engineering office, most of my reports were written for clients who paid for them and those reports arn't public. But since I am retired, I write reports mainly because I like it to do so and because during writing and calculating a faint idea can become more and more solid. The reports are now made public for free because I no longer need income for the spent time. To make that ideas become reality one should describe them as accurate as possible, such that others can study the idea, give comment and sometimes find inspiration for their own developments. It may take years until a certain idea is picked up by someone but if the idea is published on the Internet, it will not be lost. In the past I have built many wind turbines and generators and I have measured them to verify if things really work how it was expected. But I am 70 years now and although I still like it to design things, building and testing has no longer priority for me.

DamonHD

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Re: Report KD 634 about water pumping available
« Reply #3 on: July 01, 2017, 03:26:15 AM »
I agree with your philosophy: thanks for making stuff available for others to chew over.

I think an issue here is that marketing droids have overused the word FREE (as a hook to something that isn't) so much that it has a bad smell.

Maybe if you worded your posts a little more like: "I have another report (KDXXX) where I look at ..." it would feel less like a sales pitch, and more like the generous share that it is.

Dunno, aggressive sales and marketing keep poisoning that well, which is not your fault.

Rgds

Damon

electrondady1

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Re: Report KD 634 about water pumping available
« Reply #4 on: July 01, 2017, 06:38:37 AM »
could you post a link or a diagram of the poly transmission ?


Adriaan Kragten

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Re: Report KD 634 about water pumping available
« Reply #5 on: July 02, 2017, 02:21:46 AM »
A picture of the Polycord transmission is given in figure 8 of KD 634. Polycord is a brand name of the Dutch company Habasit of a round string especially designed to transfer power. I have used the largest available string diameter of 15 mm for the VIRYA-3.4. The advantage of a round string is that it can be bent in every direction. The VIRYA-3.4 has an eccentricity e of about 10 % of the rotor diameter and with a round string this eccentricity can be bridged and simultaniously an accelerating gear ratio can be realised. Acceleration of the rotational speed is necessary to get a sufficient high rotational speed of the pump and to reduce the reaction torque of the vertical shaft on the head. This reaction torque has an influence on the safety system which turns the head out of the wind at high wind speeds. The geometry is chosen such that the head turns more out of the wind if there is no load (for instance if the well is empty). All formulas to calculate this transmission are given in public report KD 320. In appendix 1 at the end of report KD 320, a copy of the Polycord folder is given.

I have researched different options to bridge the eccentricity and to create an accelerating gear ratio and I found that using a round string is the simplest and cheapest option. It also has as advantage that it contains no oil. The string is running in a wheel with a rounded 60 degrees V-groove. A requirement for proper functioning is that the string enters and leaves the wheel exactly tangential. I have used a big wheel on the rotor shaft, a small wheel on the vertical shaft and one auxiliary wheel which has the same diameter as the small wheel on the vertical shaft. The axis of the auxiliary wheel is horizontal but makes an angle of 45 degrees with the rotor shaft. The spanned bow is 270 degrees for the big wheel on the rotor shaft, 225 degrees for the wheel on the vertical shaft and 90 degrees for the auxiliary wheel. The vane arm also makes angle of 45 degrees with the rotor shaft and the axis of the auxiliary wheel is therefore in parallel to the vane arm which simplifies the technical construction. The string has a pre-tension of 8 % of the length and the position of the auxiliary wheel can therefore be fixed.
« Last Edit: July 02, 2017, 02:32:16 AM by Adriaan Kragten »

electrondady1

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Re: Report KD 634 about water pumping available
« Reply #6 on: July 02, 2017, 06:04:31 AM »
did you actually build this machine or is this a theoretical exercise?
i found a technical drawing describing the auxiliary  wheel and later a photo compilation of industrial uses of polycord.

i am thinking of building a wind wall using multiple v.a.w.t. linked with a poly-cord belt.  all  to  drive a single alternator and was curious about your experience in welding and tensioning  the material.




george65

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Re: Report KD 634 about water pumping available
« Reply #7 on: July 02, 2017, 06:40:07 AM »

That stuff is different to what I knew as polycord years ago.

What I knew it as was a round, hollow material that you could join with an internal push together fitting like a double arrow head.  I remember going to my girlfriends place ( now my wife of 25 years) and my car was getting hot having dropped the fan belt.  Didn't know where I was going to get one being a sunday evening but her father went up the back and brought this stuff back, Measured, cut and joined it and fitted it up. It was a fluro green stuff.
He worked in the aerospace industry and they used it in the factory on different machinery.

Of course only being a temporary measure, I forgot about it for 3 months till I went to change the oil and spotted it again.  Given this fragile and weak looking plastic joiner thing, it was capable of transmitting power way beyond what I would have expected. As father pointed out though, try pulling the connection apart again.
 Really handy stuff for making all sorts of belts and you could twist and wrap multiple turns direct on shafts without a pulley. The other thing was being round, you could drive pulleys at 90o to each other off the same belt and drive off any "side".

Other one they used that you could make up to any size was like a leather looking  flat linked stuff. Had metal pins in it and slots that went from wide to narrow. Worked like buttoning up your trousers above the fly only in a continous belt.  Just add as many links as you like for the size you need. 

dnix71

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Re: Report KD 634 about water pumping available
« Reply #8 on: July 02, 2017, 10:00:24 AM »
george65 I remember the polycords you mention. They were expensive, unless you considered the downtime/towing charges they saved. I used to drive 100+ miles a day on a local pickup/delivery route for a printer. The polycord we remember went out of favor when car makers switched from fractional horsepower v-belts to using flat cogged drive belts, although they are still sold as emergency belts for a/c air handlers.

Adriaan Kragten

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Re: Report KD 634 about water pumping available
« Reply #9 on: July 02, 2017, 01:58:00 PM »
The Polycord string I am talking about is massive. Both ends of the string are hot welded together with a welding mirror, so every length can be made. It is also possible to order a welded string of a certain length. The material is very strong. The 15 mm string has a breaking strength of 7000 N. Detailed information about the Polycord string is given in the folder in appendix 1 of KD 320 (in German). Some examples of machines in which this type of string is used are also given in this folder.

I hav'n't built the Polycord transmission myself but a friend of mine has built such transmission for a water pumping windmill in Nicaragua. However, he made the wheels from 360 degrees bent angle iron. In this way the V-groove had a much too large angle, the groove surface was too rough, the concentricity of the wheels was too bad and the string wasn't running in and out exactly tangentially. So this transmission failed because the string was slipping and running out of the grooves. But it must work fine if the wheels are made on a lathe out of aluminium, if the geometry is chosen correctly and if the maximum torque level matches with the allowable net string force. I have made calculations in KD 634 which show that the chosen string is strong enough.

I would use the Polycord transmission only when bending of the string in different directions is necessary like it is the case for my transmission. If you want to connect two parallel shafts, you can better take a flat string or a multi V-belt like it is used in certain washing machines. In this case a very large transmission ratio can be realised and because of the large spanned bow on the big wheel, no grooves in the big wheel are required.
« Last Edit: July 02, 2017, 02:04:21 PM by Adriaan Kragten »