Stats for a TL2 or 3 pump?

Ultraviolet · 08-15-2018, 01:55 AM

Greetings
I can't seem to find anything in Low Tech. Does anybody have stats for early pumps? Weight, how much water can be moved etc?

I'm thinking Archimedes screw or something, perhaps that's even as low as TL1.

(E) · 08-15-2018, 02:54 AM

Two of the earlier methods for moving water are shadoofs and chain pumps.
A shadoof is functionally a lever for lifting water. Maybe lifting it 2 times the users height.
Chain pumps can move water higher (noria and Sakia are two variations)
How much volume depends on the power source, oxen can pull their own body weight all day with the right yoke. So that gives you a number for the maximum weight lifted. Subtract a number for the losses due to friction and mechanical inefficiencies (I have no idea to be honest) 80% maybe which multiplied by an RPM of 3 means about 300 litres a minute up to a height of maybe 3 meters. This is educated guessing though.

Individual archimedes screws don't offer a lot of height. I'm not sure how efficient the are. As power generators they are very efficient but I'm not sure how that translates

Then there is Ctesibius who developed (or is associated with) an early reciprocating pump.

Also most pumps are complicated in terms of calculating how much water is moved because the height and distance the water has to travel are also issues.

Kelly Pedersen · 08-15-2018, 05:05 AM

You can find stats for some water-moving equipment (shadouf, Archimedean screw, saqiya, and bucket chain) in Low-Tech Companion 3: Daily Life and Economics, in "Irrigation and Hydraulics" (pp. 17-18). Unfortunately, neither the Low-Tech Companion nor Low-Tech proper seem to have any stats on just a pump proper.

Ultraviolet · 08-15-2018, 01:22 PM

Quote:

Originally Posted by Kelly Pedersen

You can find stats for some water-moving equipment (shadouf, Archimedean screw, saqiya, and bucket chain) in Low-Tech Companion 3: Daily Life and Economics, in "Irrigation and Hydraulics" (pp. 17-18). Unfortunately, neither the Low-Tech Companion nor Low-Tech proper seem to have any stats on just a pump proper.

Ah thanks. I don’t have that particular book but I thought there might be one with that.

Pursuivant · 08-15-2018, 04:46 PM

It's early TL5, but here are the stats for the patent pumps aboard the USS Constitution, but it doesn't list the number of crew required to operate it:

https://ussconstitutionmuseum.org/20...-constitution/

Chain and rope pumps date back to TL1, and this paper has data on their efficiency:

https://www.arrakis.nl/reports/06092...rs-Rijs_lr.pdf

08-15-2018, 01:55 AM	#1
Ultraviolet Join Date: Apr 2008 Location: Århus, Denmark	Stats for a TL2 or 3 pump? Greetings I can't seem to find anything in Low Tech. Does anybody have stats for early pumps? Weight, how much water can be moved etc? I'm thinking Archimedes screw or something, perhaps that's even as low as TL1. __________________ Playing GURPS since '90, is now fluent in 4th ed as well.

08-15-2018, 02:54 AM	#2
(E) Join Date: Jul 2014 Location: New Zealand.	Re: Stats for a TL2 or 3 pump? Two of the earlier methods for moving water are shadoofs and chain pumps. A shadoof is functionally a lever for lifting water. Maybe lifting it 2 times the users height. Chain pumps can move water higher (noria and Sakia are two variations) How much volume depends on the power source, oxen can pull their own body weight all day with the right yoke. So that gives you a number for the maximum weight lifted. Subtract a number for the losses due to friction and mechanical inefficiencies (I have no idea to be honest) 80% maybe which multiplied by an RPM of 3 means about 300 litres a minute up to a height of maybe 3 meters. This is educated guessing though. Individual archimedes screws don't offer a lot of height. I'm not sure how efficient the are. As power generators they are very efficient but I'm not sure how that translates Then there is Ctesibius who developed (or is associated with) an early reciprocating pump. Also most pumps are complicated in terms of calculating how much water is moved because the height and distance the water has to travel are also issues. __________________ Waiting for inspiration to strike...... And spending too much time thinking about farming for RPGs Contributor to Citadel at Nordvörn Last edited by (E); 08-15-2018 at 01:24 PM.

08-15-2018, 05:05 AM	#3
Kelly Pedersen Join Date: Aug 2005 Location: Saskatoon, SK, Canada	Re: Stats for a TL2 or 3 pump? You can find stats for some water-moving equipment (shadouf, Archimedean screw, saqiya, and bucket chain) in Low-Tech Companion 3: Daily Life and Economics, in "Irrigation and Hydraulics" (pp. 17-18). Unfortunately, neither the Low-Tech Companion nor Low-Tech proper seem to have any stats on just a pump proper.

08-15-2018, 04:46 PM	#5
Pursuivant Join Date: Apr 2005	Re: Stats for a TL2 or 3 pump? It's early TL5, but here are the stats for the patent pumps aboard the USS Constitution, but it doesn't list the number of crew required to operate it: https://ussconstitutionmuseum.org/20...-constitution/ Chain and rope pumps date back to TL1, and this paper has data on their efficiency: https://www.arrakis.nl/reports/06092...rs-Rijs_lr.pdf

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