Small engine driven water pump

H

Half Pipe

Member

• Jun 15, 2018

• #1

Are the small most likely Chinese water pumps any good?
Something like
https://hyundaipowerequipment.co.uk/hyundai-dhy80e-80mm-electric-start-diesel-water-pump/
How much does a long run of pipe affect it?
Would like to pump water 150m with 2m lift on suction side and 9/10m on outlet

 

Pheasant Surprise

Member

Location

Woodbridge, Suffolk

• Jun 15, 2018

• #2

Looks ok to me.

A 3” bore will have way, way less frictional loss along the pipe, than a 2” pipe.

For that size of portable pump 3” is about the biggest you can reasonably expect to go.

 

Speedstar

Member

Location

Scottish Borders

• Jun 15, 2018

• #3

We have had a few like that,cheap but they only last a year or so as they break the end off for crankshaft were the impeller drive's from

 

H

Half Pipe

Member

• Jun 15, 2018

• #4

@Pheasant Surprise @Speedstar do you think it will still have a reasonable flow rate with 150m pipe and the 10m lift?

 

Kidds

Member

Horticulture

Location

Near Beeston Castle

• Jun 15, 2018

• #5

The flow rate chart for that pump says it will work at that head, assuming minimal frictional losses through a 3" pipe it should be fine.
(someone more educated on such matters should be consulted before using my assumptions)

 

H

Half Pipe

Member

• Jun 15, 2018

• #6

@Kidds I was working on same assumptions and used this loss calculator
http://www.marispumps.com/pressure-drop-calculator.php

It comes up with just short of 6m head loss at 500l/m on 150m

 

Mursal

Member

• Jun 15, 2018

• #7

Hire first, then decide ...............
Hire as close to the spec of the above pump, as you can

Wonder can you get replacement crankshafts for them?

 

Pheasant Surprise

Member

Location

Woodbridge, Suffolk

• Jun 15, 2018

• #8

Total static head = 10m - (-2m) = 12m

Approx. frictional head loss of 150m of 75mm pipe = 18m (according to frictional loss calculator for 55 cube/hr of flow)

Total differential head needed at pump = 12m + 18m = 40m 30m

Pump has 34m of head in total (8m suction + 26m Pressure)

Edit - doh! can’t add up!!! 12 + 18 = 30!

 

Last edited: Jun 15, 2018

H

Half Pipe

Member

• Jun 15, 2018

• #9

@Pheasant Surprise
The part that puzzles me, I presume flow rate drops as head rises!?
Does this mean the friction loss in the pipe drops or does the shear weight of 3" of water in a length of pipe stop flow.

My 2nd thought , if pump not capable, would it manage if had a 2nd pump at 75m?
What problems would this create?

 

H

Half Pipe

Member

• Jun 15, 2018

• #10

Mursal said:

Hire first, then decide ...............
Hire as close to the spec of the above pump, as you can

Wonder can you get replacement crankshafts for them?

Click to expand...

Like the idea of hire 1st easiest way to see if works or not.

I would think replacement crank be available as most copies of yanmar style engines. But cost of replacement crank and work involved probably means engine be scrap

 

Pheasant Surprise

Member

Location

Woodbridge, Suffolk

• Jun 15, 2018

• #11

Half Pipe said:

@Pheasant Surprise
The part that puzzles me, I presume flow rate drops as head rises!?
Does this mean the friction loss in the pipe drops or does the shear weight of 3" of water in a length of pipe stop flow.

My 2nd thought , if pump not capable, would it manage if had a 2nd pump at 75m?
What problems would this create?

Click to expand...

So for a given size/smoothness of pipe the frictional loss increases as you increase the flow. Try it in the calculator for different flow rates. You must assume a flow rate that the pump can manage as per below.

The Hyundai pump head vs flow diagram assumes just static head (as they don’t know about what length /size pipe your using) so that is the theoretical volume of water the pump will shift for a particlular static head.

The total dynamic head @ the pump = frictional loss (of pipe at said flow) + static head.