What size pump for a 200 ft well?

Marine propulsion system

A pump-jet, hydrojet, or water jet is a marine system that produces a jet of water for propulsion. The mechanical arrangement may be a ducted propeller (axial-flow pump), a centrifugal pump, or a mixed flow pump which is a combination of both centrifugal and axial designs. The design also incorporates an intake to provide water to the pump and a nozzle to direct the flow of water out of the pump.[1]

Design

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A pump-jet works by having an intake (usually at the bottom of the hull) that allows water to pass underneath the vessel into the engines. Water enters the pump through this inlet. The pump can be of a centrifugal design for high speeds, or an axial flow pump for low to medium speeds. The water pressure inside the inlet is increased by the pump and forced backwards through a nozzle. With the use of a reversing bucket, reverse thrust can also be achieved for faring backwards, quickly and without the need to change gear or adjust engine thrust. The reversing bucket can also be used to help slow the ship down when braking. This feature is the main reason pump jets are so maneuverable.

The nozzle also provides the steering of the pump-jets. Plates, similar to rudders, can be attached to the nozzle in order to redirect the water flow port and starboard. In a way, this is similar to the principles of air thrust vectoring, a technique which has long been used in launch vehicles (rockets and missiles) then later in military jet-powered aircraft. This provides pumpjet-powered ships with superior agility at sea. Another advantage is that when faring backwards by using the reversing bucket, steering is not inverted, as opposed to propeller-powered ships.

Axial flow

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An axial-flow waterjet's pressure is increased by diffusing the flow as it passes through the impeller blades and stator vanes. The pump nozzle then converts this pressure energy into velocity, thus producing thrust.[1]

Axial-flow waterjets produce high volumes at lower velocity, making them well suited to larger low to medium speed craft, the exception being personal water craft, where the high water volumes create tremendous thrust and acceleration as well as high top speeds. But these craft also have high power-to-weight ratios compared to most marine craft. Axial-flow waterjets are by far the most common type of pump.

Mixed flow

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Mixed-flow waterjet designs incorporate aspects of both axial flow and centrifugal flow pumps. Pressure is developed by both diffusion and radial outflow. Mixed flow designs produce lower volumes of water at high velocity making them suited for small to moderate craft sizes and higher speeds. Common uses include high speed pleasure craft and waterjets for shallow water river racing (see River Marathon).

Centrifugal flow

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Centrifugal-flow waterjet designs make use of radial flow to create water pressure.

Examples für centrifugal designs are the Schottel Pump-Jet and outboard sterndrives.[2]

Advantages

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Pump jets have some advantages over bare propellers for certain applications, usually related to requirements for high-speed or shallow-draft operations. These include:

History

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The water jet principle in shipping industry can be traced back to 1661[4] when Toogood and Hayes produced a description of a ship having a central water channel in which either a plunger or centrifugal pump was installed to provide the motive power.[5]

On December 3, 1787, inventor James Rumsey demonstrated a water-jet propelled boat using a steam-powered pump to drive a stream of water from the stern.[6][circular reference] This occurred on the Potomac River at Shepherdstown, Virginia (now West Virginia) before a crowd of witnesses including General Horatio Gates. The 50-foot long boat traveled about one-half mile upriver before returning to the dock. The boat was reported to reach a speed of four mph moving upstream.[7][8][9]

In April 1932, Italian engineer Secondo Campini demonstrated a pump-jet propelled boat in Venice, Italy. The boat achieved a top speed of 28 knots (32 mph; 52 km/h), a speed comparable to a boat with a conventional engine of similar output. The Italian Navy, who had funded the development of the boat, placed no orders but did veto the sale of the design outside of Italy.[10][11] The first modern jetboat was developed by New Zealand engineer Sir William Hamilton in the mid 1950s.[12]

Uses

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Pump-jets were once limited to high-speed pleasure craft (such as jet skis and jetboats) and other small vessels, but since 2000 the desire for high-speed vessels has increased[citation needed] and thus the pump-jet is gaining popularity on larger craft, military vessels and ferries. On these larger craft, they can be powered by diesel engines or gas turbines. Speeds of up to 40 knots (45 mph; 75 km/h) can be achieved with this configuration, even with a displacement hull.[13]

Pump-jet powered ships are very maneuverable. Examples of ships using pumpjets are the Car Nicobar-class patrol vessels, the Hamina-class missile boats, Valour-class frigates, the Stena high-speed sea service ferries, the United States Seawolf-class and Virginia-class, as well as the Russian Borei-class submarines and the United States littoral combat ships.

See also

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Notes

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References

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• Charles Dawson, "The Early History of the Water-jet Engine", "Industrial Heritage", Vol. 30, No 3, 2004, page 36.
• David S. Yetman, "Without A Prop", DogEar Publishers, 2010

On Sun, 27 Jan 2002 08:20:43 -0800, capw < ca...@charter.net > wrote:

>
>
>basil...@zotnet.net wrote:
>
>>
>> Every gallon per minute of water pumped from that depth will require
>> 0.0376 kW divided by the pump efficiency and divided again by the
>> motor efficiency. Typical pumps in this size range 80 gpm at 200' of
>> head (not counting the additional head required for line loss in the
>> casing, surface piping, etc.) are in the 50% range and motor
>> efficiencies in the 90% range so, each gallon per minute will need
>> about 0.084 kW or 6.7 kW for the 80-gpm pump. Figuring 25% extra head
>> for the line losses, etc., this comes to about 8.4 kW.
>
>There appears to be an error in numbers... he was looking for about 80 gal per
>hour, not 80 gal per minute.. So 0.084* 8= 0.672 KW.. * 1.25 ( head loss) =
>0.84. Figuring in 1.25 % for generator capacity equals 1.05 KW generator.

0.084 kW/gpm x 1 gpm/60 gph x 80 gph = 0.112 kW x 125% = 0.14 kW

>
>>
>>
>> Most diesel generators like to run at about 80% of load. So, a 10 kW
>> generator seems to be about right for this application. This figures
>> to be about 0.1 or so gallons per hour for a good engine. An hour's
>> run would put in 4800 gallons. So a 5000 gallon tank with the turn on
>> setting at 200 gallons would need to run about an hour to fill.
>
>Again the numbers need to be crunched.. 1kw generator at 0.01 gal hr fuel( is
>that right? ) will put out 480 gal/hr... at diesel at $1.35 per gallon, and
>0.01 gal/hr used, That's $1.35 per 48,000 gallon. of water pumped or 36,000
>gallons or water per dollar.

I made a mistake in my number above. One kilowatt would use about
14,000 Btu/hr (for an efficient generator). So, 10 kW would use about
140,000 Btu/hr. Since one gallon of Diesel has about 144,000 Btu, one
could say that the 10-kW unit would use about 1 gallon per hour.

Off-road diesel is about 60｢/gallon. It is possible to find very small
generators. However, it seems like this would be a good application
for a shorter run time unit that would be more fully loaded.

If the folks used 1000 gallons per day. They could use a 5000 gallon
tank and the 80-gpm pump to fill it. On the other hand if the well can
only produce 80-gph, then a smaller generator or photovoltaic system
could be used along with a smaller tank.

As you have said, there are lots of numbers to be crunched and too
many assumptions to be definite without more information.

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