Author Topic: More Water Pump Discussions  (Read 3166 times)

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t_hunter44

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More Water Pump Discussions
« on: October 04, 2010, 01:41:21 PM »
Commando Congrats for finding the items. I also have a project now at 80 feet deep and water starts coming in and I expect the target around 120 feet. The water pump that someone loaned to me is a 7 horse power centrifugal pump but cannot do the job. May I ask what kind what kind of a water pump have you used to get that water out at a 100 feet or more so that I can continue the project. Thank you in advance for your help, again my congratulation.
    
First, we used 3 hp submersible water pump then coupled with another 3 hp centrifugal pump. If still cannot bring up water, then add another 2 hp centrifugal pump. We did'nt used bigger pump because it's very hard to manipulate under the hole.

With Commandos illustration. he did actually put the engine driven centrifugal pump inside the hole, where he located the 2 HP centrifugal pump is anybody's guess but because of the statement he made on the last part "We did'nt used bigger pump because it's very hard to manipulate UNDER the hole", so he is saying he also placed the 2 HP centrifugal pump inside the hole. Just makes me wonder if anybody was a victim of Carbon Monoxide poisoning like the other unfortunate treasure hunters recently that made the mistake of bringing down the Engine Driven Centrifugal Pumps inside their diggings.  Commando, you are welcome to refute this post, you cannot delete it for sure now that the Moderator job was taken away from you. ;D
« Last Edit: October 04, 2010, 01:44:32 PM by t_hunter44 »

Angel_09

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More Water Pump Discussions
« Reply #1 on: October 04, 2010, 03:17:17 PM »
Observation and comments:

In fairness, I re-read the postings from beginning to the end and I did not found about the centrifugal pump driven by engine. Centrifugal pump does not necessarily mean "engine driven" since it can also be driven electrically...whatever horsepower.

Commando's method is the most logical approach because of the depth of the hole, and height displacement of centrifugal pumps is proportional to the vacuum/athmospheric pressure relationship which limits the displacement of liquid. However, in positive displacement pump, height does not matter since water can be push to its higher level provided the motor or engine can carry and sustain the weight of the fluid.

In series method, it is always necessary that submersible pump should be the first to use to convert the suction lift to discharge head. In order to utilize the maximum head of the pump, the level of liquid should be within the suction level of the next pump (electric driven centrifugal pump) which will be 0 height, thus, the total dynamic head will be the total discharge head. If the next pump is connected above the maximum discharge level, it will create a void gap in between the fluid level and the suction level of the pump, so that even it is a high capacity pump, water can not be moved because of the air in the void gap. The principle of the centrifugal pump is that the suction level must be "solid" (full of liquid) so that movement will happen. By principle, submersible is also categorized as centrifugal pump, not by construction, but by principle of operation.

My 2 cents

Angel_09

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More Water Pump Discussions
« Reply #2 on: October 04, 2010, 03:53:39 PM »
To illustrate my statement. please check my drawing:
« Last Edit: November 10, 2010, 02:22:33 PM by Angel_09 »

Angel_09

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More Water Pump Discussions
« Reply #3 on: October 04, 2010, 04:28:26 PM »
Below is the 2nd illustration if the pump is wrongly placed or connected.
« Last Edit: November 10, 2010, 02:22:08 PM by Angel_09 »

Offline Janner

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More Water Pump Discussions
« Reply #4 on: October 04, 2010, 04:48:14 PM »
Technical discussions in the correct area please.......(you move them or i will)

Angel_09

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More Water Pump Discussions
« Reply #5 on: October 04, 2010, 05:44:17 PM »
Janner,

I agree to move the # 67 and # 68 reply to technical discussion.

But reply # 66 which is observation and comments should stay as it explains and probably helps to resolve the misunderstanding about pumps between TH_44 and Commando.

Offline Janner

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More Water Pump Discussions
« Reply #6 on: October 04, 2010, 05:48:59 PM »
ok, for the moment,

waiting for a reply from T44

t_hunter44

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More Water Pump Discussions
« Reply #7 on: October 05, 2010, 09:47:26 AM »
Observation and comments:

In fairness, I re-read the postings from beginning to the end and I did not found about the centrifugal pump driven by engine. Centrifugal pump does not necessarily mean "engine driven" since it can also be driven electrically...whatever horsepower.

Commando's method is the most logical approach because of the depth of the hole, and height displacement of centrifugal pumps is proportional to the vacuum/athmospheric pressure relationship which limits the displacement of liquid. However, in positive displacement pump, height does not matter since water can be push to its higher level provided the motor or engine can carry and sustain the weight of the fluid.

In series method, it is always necessary that submersible pump should be the first to use to convert the suction lift to discharge head. In order to utilize the maximum head of the pump, the level of liquid should be within the suction level of the next pump (electric driven centrifugal pump) which will be 0 height, thus, the total dynamic head will be the total discharge head. If the next pump is connected above the maximum discharge level, it will create a void gap in between the fluid level and the suction level of the pump, so that even it is a high capacity pump, water can not be moved because of the air in the void gap. The principle of the centrifugal pump is that the suction level must be "solid" (full of liquid) so that movement will happen. By principle, submersible is also categorized as centrifugal pump, not by construction, but by principle of operation.

My 2 cents
   So you reread the postings in question and you took it upon yourself to answer for Commando, that is nice of you. Janner on his post#1115 asked, you placed the pump inside the hole, Commandos response, post@119, what is wrong with using submersible pump in the hole. For the bottom pump, yeah, its good but the centrifugal pump according to his illustration, if that was a submersible pump also as he claims, after Janners question, one cannot couple it to the bottom pump as illustrated. Look at A submersible pump construction, do you see a place to connect , no hose connection as the Suction is normally built in the bottom of the Submersible Pump.  Now, if the First Stage is pumping to a Container like a drum, the Second Stage Subpump is placed in that drum to pump out to the the outside or to another stage if necessary. Now, let us see what you have describe or illustrated here. Nice but why ZERO height on your Suction Head or Suction Lift on your Electric Driven Centrifugal Pump, don't they Normally have a Suction Lift. Most Centrifugal Pumps that I know has a Suction Lift,(we are not talking booster pumps I hope) my 3/4 HP electric water pump that provides water for my house in the province has a 25 feet suction lift and my 7 HP Honda Engine Driven Trash  Pump has a 25 feet suction lift. Why even buy a Centrifugal pump that has 0 suction lift. If your First Stage Subpump(Bottom Pmp) has a 40 foot TDH, you can place your Second Stage Electric Driven Centrifugal Pump at 60 feet if it has a Suction Lift of 30 Feet as it is within range of the TDH of the First Stage Pump with 10 feet to spare.Just my 2 cents worth. I suppose illustration is not necessary but that can be provided if necessary.
« Last Edit: October 05, 2010, 12:50:53 PM by t_hunter44 »

Angel_09

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Re: More Water Pump Discussions
« Reply #8 on: October 05, 2010, 10:59:22 AM »
TH-44,

Yes I re-read the postings to understand the root of confusion in the discussion, but not to ANSWER for Commando nor do side for Commando, but to the preciseness of the information. It is the reason why I titled it OBSERVATION AND COMMENTS, to provide additional information about the topic.
I'm trying to check the source of your statement about the assumed 2 submersible pump connected in series but I can't find it. In reality, two submersible pump can not be connected physically, but can be connected theoretically by using 'medium in between suction and discharge, which may be a drum or anything that can hold water. With this, it can only be assumed that if both pumps are connected physically, then one is submersible and the other is electrically driven centrifugal pump.

Regarding suction lift/head, most centrifugal pumps have suction head, with the exception of submersible pump.  Total dynamic head  (TDH) is the sum of suction head plus the discharge head. As the suction head decreases, the discharge head increases and vice versa. It is the reason why some hunters are lowering their engine driven pump to the hole, to lessen the suction head and increase the discharge head, unknowingly, that it is dangerous to themselves.
My previous illustrations explain most of the things about pump's TDH.

My 2 cents

t_hunter44

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Re: More Water Pump Discussions
« Reply #9 on: October 05, 2010, 01:07:55 PM »
So you did not really read what was written on the Post of Commando, the question of Janner and Commandos reply to Janner and mine. One has to understand what was written and what was not written, reading between the lines, no further argument there. TDH=Static Lift+Static Height+Friction but one cannot see those on the Pump Specs if you are buying one but it will have the Suction Lift and Discharge Head in feet so tell that to the pump prospective buyers here to look for TDH. Myself, I make things simple, know the Suction Lift and the Discharge Head in feet, GPM and the Manufacturer, particularly the engine, as  simple as that. Chao, everybody have a nice day.

Angel_09

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Re: More Water Pump Discussions
« Reply #10 on: October 05, 2010, 01:45:37 PM »
Th_44,

I did not say I didn't read it, I said I can't find it. I read  in your written post referencing #1115 and post@119, which is the basis of my remarks, and I didn't found anything about 2 centrifugal pumps except the assumption that he used 2 submersible pumps. Anyway, as you had said, no further argument there.

In some pumps, especially those small one used domestically, they only use the term GPM/Hr to denote displacement; volume/height to indicate 'head' and some other information. But in bigger pumps, there are always brochures that gives information about 'pump curves' that tells all the specifications and purpose of usage, and all these things are simple information, but because of its simpleness, sometimes it is often neglected and overlooked by the users. And it is the reason why I am putting some information regarding this topic. To remind them these simple things they previously know but had been overlooked in due course of time.
To ease the burden to others, I will reiterate this statement: "As the suction head decreases, the discharge head increases and vice versa."

Ciao

t_hunter44

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Re: More Water Pump Discussions
« Reply #11 on: October 05, 2010, 03:03:15 PM »
Amen to that. Let us just try to make it simple here for the guys that are not technically inclined. With the discussion we have, it was very informative and I hope the guys here learned something from it. Chao I tend to be more Vietnamese as I was in Nam for a year and Ciao is more Italian but I should use it too as I am sort of Aetaliano, Aeta and Ilocano. ;)
« Last Edit: October 07, 2010, 01:30:31 PM by t_hunter44 »

Angel_09

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Re: More Water Pump Discussions
« Reply #12 on: October 05, 2010, 03:24:09 PM »
Cheers to that TH-44... :D

So how's Ho ching Mi? Do 'motorbikes' still rule the road?
 I love the seafoods restaurant there.... ;)

Offline ghost

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Re: More Water Pump Discussions
« Reply #13 on: October 05, 2010, 03:27:36 PM »
For as long as we learn and benifit from the on going discussions, fine for me. The subm pump first then series it with either electric pump or engine driven pump but not inside the hole is the best solution. Somebody will question about the height of displacement again but that will depend now on the actual dig. I used this tandem on my last proj and its good.

Offline Janner

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Re: More Water Pump Discussions
« Reply #14 on: October 05, 2010, 03:30:16 PM »
Vietnam...well nice place, spent 6 yrs there, but they were not so friendly then...always hiding in tunnels.. :D

and now its a new place, go there every year to see friends....