1. #1
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    Default Rear Mount Pump Questions

    Is it possible to have a 2 stage rear mounted pump? If so, can anyone explain the required mechanics for powering a big rear mounted pump. Traditionally having only worked with midship pumps, I saw the question posted elsewhere and from what I can find, there's no manufacturers offering 2 stage rear mount pumps.

    I believe, if I have been told correctly, that it wasnt possible for larger pumps to be utilized in front or rear configurations when they were only able to be PTO powered because the PTO wasnt capable of supplying enough power to move larger flows. Is this also true?

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    Our Darley/Freightliner 112 powers a 1,500 gpm rear mount with a 220 CFM CAFS compressor.

    It has a Cummins ISM 500hp engine with an Allison HD4066.

    The pump and compressor are run off of one PTO and a 25KW generator runs off the other PTO.

    Read Allison's specification sheet regarding available torque at the PTO.

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    Yes, it is possible to rear mount a 2-stage pump. There have been many apparatus built that way. It can either be pto driven or split shaft driven. The pto driven pump may have some rating limitations and the split shaft would not. Feel free to e-mail me if you would like more information on the 2-stage rear mount.

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    If I may, could I ask an additional question about rear mounts? Is it not a pain ( if you run them dry ) to run back, open tank to pump valve, run back, put it in gear, run back and do the rest ? Or can you run them wet more often since they seem to be in more of a compartment and then, easier to heat? Just wondering. Not trying to hi-jack this thread.

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    What do you keep running for? You put the pump in gear when you exit the cab and everything else is at the pump panel. They can be heated easier because the rear compartment usually has a complete floor in it and you can run a pump heater line to the compartment.

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    Can anyone steer me towards some manufacturers/model numbers and capacities of such pumps?

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    I would recommend taking a look at Rosenbauer's Tech Drive Rear Mount Pumper. Regardless of the manufacturer, there are quite a few good ideas put into this truck.

    They have a 2000 GPM on this truck.

    There is a video on their website that is well worth watching.

    http://rosenbaueramerica.com/Apparat...mper/Index.cfm

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    BigJim, my question (i'm not a qualified pump operator) was in reference to hearing everyone at my station talk about not running the pump dry. Hence my question about going from the in cab pump shift to the control for the tank to pump valve. We tend to keep pumps dry here in winter. But if the pump can be warmed easily I guess its a not very important point.

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    MG3610 - Just curious what size pump you would be looking for that would need 2 stages with today's engines?

    CdnFyreGuy - for the small amount of time it takes to enter water in the pump, it shouldn't make a difference.

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    So I could start the pump dry, then head back to the panel and open tank to pump.......thank you Spencer534.

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    Hey CdnFyreGuy,

    I wanted to add more to my post, but caught a call.

    I won't say I'm an expert, but I have always been told that you should recirculate if you aren't flowing water for more than 3 minutes. And that is while pumping which means more psi than when you are at idle and engaging the pump.

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    It won't hurt the pump to run dry for a few minutes. What you don't what to do is make it a habit of engaging the pump and not geting some water into it.

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    Quote Originally Posted by bigjim1301
    It won't hurt the pump to run dry for a few minutes. What you don't what to do is make it a habit of engaging the pump and not geting some water into it.
    Doesn't the type of seals being used have alot to do with running the pump dry even for just a "few minutes" ?

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    Considering the fact the we just ordered two 1500 GPM Rear Mount Engines I could probably answer some of the questions. First of all, yes you can have a two-stage rear mount. There are numerous ways of doing a rear mount. When at General Safety, I saw a midship pump located at the rear powered via a pto shaft so that would be one way of doing it.Be aware that you are limited to 1250 on a pto pump.Our pumps are split shaft driven just like a traditional mid ship pump only using a "doughnut" pump.Like mentioned earlier, have a look at the Rosenbauer America site. I think they offer a 1500 GPM pump that can produce a hi and low pressure at the same time.

    A rear mount is no easier to "warm" as it is out in the open just like a midship, it's usually just the pump panel that is in a compartment.

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    Victoria,

    I didn't know anyone speced two-stage pumps anymore unless they were specialty pieces (i.e. satellite systems). I was under the impression that two-stages went out when engines started going to diesel power. The old gas engines could not produce enough juice to provide the high pressure used by today's FF. I do know that you don't have to have 2 stage pumps for 1500gpm. I'm not saying its right or wrong, just curious why ya'll speced them that way.

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    I would look General Safety's way for some rear-mount answers as well. We have a midi-unit coming with a rear mount, but we're running this rig with a 1,000 gpm pump with PTO drive.

    Regardless of what you think about General Safety, they have built a good number of rear mount units. Saulsbury had as well, though I suspect the talent that was at Saulsbury when those rigs were built didn't move to the warmer climate.

    Really though - perhaps contacting the different pump manufacturers would be the real way to go - get your info straight from the horse's mouth, etc.

    A lot of folks won't consider their products, but Rosenbauer's pumps are available with an auto-prime option. Engage the pump, the primer automatically engages until the pump is primed, and it shuts off. I think Rosenbauer's stuff is available up to 1250 gpm here in the states now.

    Not a Rosenbauer salesman, just familar with their stuff...

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    Yes, the Rosenbauer pump is able to pump at both Normal and High Pressure simultaneously. NFPD801 is right, the NH1250 is now being sold in the United States.

    The auto prime option is a rather interesting feature and seems to work quite well. If you ever get a chance to take a look at this pump, I would highly recommend it.

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    Todd,

    I am trying to learn more. The Rosenbauer pump can pump in normal and high pressure. What is high pressure? Are we talking about the old high pressure/low gpm lines that used to have the space-ray looking nozzles or something else?

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    Quote Originally Posted by Spencer534
    Todd,

    I am trying to learn more. The Rosenbauer pump can pump in normal and high pressure. What is high pressure? Are we talking about the old high pressure/low gpm lines that used to have the space-ray looking nozzles or something else?
    Yup. I believe on the discharge side of the pump it has a special pressure manifold to accomodate a high pressure (CAFS or foam ??? ) line.

    NFPD must have the scoop on that though, I'm not too familiar with it.
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    The Rosenbauer series of pumps will pump at pressures higher up (I want to say 600 psi) on the high side of the pump. The pump will also continue to pump normal pressures on the other side of the pump, so you can continue to flow your normal handlines. (There's basically a side of the pump with a conventional single stage impeller, and another side with a three stage impeller).

    Rosenbauer NH series

    Why did we go with it?

    Need for a rear mount PTO pump. We liked the midi engine concept with a rear-mount pump that could pump and roll. We're a die-hard Hale department, but the Rosenbauer pump had some ideas to try that we thought would be worth the risk.

    The booster reel line on the high pressure side of the pump will flow about 100 gpm mixed with foam, which when introduced to the high pressure side produces a "CAFS like" foam. Yes, I KNOW it isn't true CAFS, but there was no way I (alright, we) could sell the CAFS concept and cost to the check writers at our department, however, we could get class A foam in the door on this rig, with hopefully great success and get future apparatus equipped with on-board class A foam.

    Will we use the high pressure side on structure fires? Maybe as an exterior exposure protection foam application, maybe on auto fires, and yes for dumpster and brush work. I also see real opportunity with the use of the high pressure line during overhaul work. Maybe the "experiment" will be an utter failure, maybe not. If so, we never use the high pressure side except for a fog for rehab. I don't know. We'll still have an 1000 gpm single stage pump in the rig.

    Someone will surely come on here and say we're destined for failure. Thanks anyway, but the truck is already bought. We'll have a dozen guys on the department that never came to a single apparatus committee meeting telling us the same thing if it doesn't work out.

    EDIT - No NASA death ray Bean nozzles, we'll be using a TFT nozzle that's designed to handle the higher pressure, but looks outwardly like any other fog. Rosenbauer did have a really funky high pressure nozzle on display when we were at the General plant, it made for a great photo op with the fighter pilot style European helmets there also.
    Last edited by npfd801; 08-20-2005 at 12:43 AM.

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    Spencer534

    No, we didn't get two-stage pumps, but I'm pretty sure you can mount a regular two stage midship pump at the rear and I was just mentioning the Rosenbauer pump as there were a few being built when I was there. Ours will have Waterous S100's rated at 1500 GPM.

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    That Rosenbauer pump looks really interesting. Let me know how it works out. It would be interesting to see the implications for overhaul. Thanks for bearing with me and the 3rd degree. I just want to know of any new technology/techniques out there.

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    No problem posting what I've learned about the Rosenbauer pump. I can guarantee you, if we have issues with it, I'll make them public.

    If I talk down a brand on here, its from personal knowledge or from an individual I inherently trust, none of the "I heard" crud.

    The second engine we have coming will have a more conventional Hale lump of metal in the middle of the truck, so it isn't like we're pushing rear-mount, high pressure pumps as the end-all solution to every fire apparatus design.

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