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Thread: Flojet pumps

  1. #1
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    Flojet pumps

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have a 1 group commercial machine which Im about to over haul. At the moment the procon pump is happy drawing from a bottle. What I want to do is fit an inline filter in between the bottle and the rotary pump.

    What I was thinking that a flojet pump would do the job of providing a simulated mains water pressure to the inline water filter, which the rotary pump will draw from. Is my thinking flawed?

    machine ------ pump ------ water filtration unit ------- flojet ------ bottle

    the reason why I want to do this is because I just want to fill the water bottle up with tap water.

    These flojet pumps are quite pricey. Are there any other pump do the same job? I know a similar set up was used for the Barista Championships this year. I may just ask John from Coffee Machine Technologies how he did it.....but would appreciate some feedback.

    Cheers,

    Dave

  2. #2
    Mal Dimal's Avatar
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    Re: Flojet pumps

    Gday Dave,

    Would it be possible to position the water bottle/tank above the machine..... This would provide a positive head on the pump through the filter and much less complex and inexpensive by comparison. If youre using bottled water mate, why do you need to filter it? I can imagine why you might want to control the water hardness via a small water softener but most decent bottled water is already filtered to a high standard....

    Mal.

  3. #3
    Sleep is overrated Thundergod's Avatar
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    Re: Flojet pumps

    Mal he said he wanted to use tap water in a bottle not bottled water.


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    Re: Flojet pumps

    Quote Originally Posted by Mal link=1217679658/0#1 date=1217681986
    Gday Dave,

    Would it be possible to position the water bottle/tank above the machine..... This would provide a positive head on the pump through the filter and much less complex and inexpensive by comparison. If youre using bottled water mate, why do you need to filter it? I can imagine why you might want to control the water hardness via a small water softener but most decent bottled water is already filtered to a high standard....

    Mal.
    Hey Mal,

    Thanks for the reply, firstly as TG said, I want to use tap water in the bottle. The procon pumps have no dramas drawing out of a tank/bottle. My problem is getting pressure to an inline water filtration system before it hits the rotary pump from the water tank.

    Cheers.

    DS

  5. #5
    jmc
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    Re: Flojet pumps

    Dave,
    What I do for my 2 group La Pavoni is filter the water as it comes from the tap, then put it into the bottle. Above counter water filters can be found online ( PM me for the people I use ) for around $100.

    John

  6. #6
    Mal Dimal's Avatar
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    Re: Flojet pumps

    Quote Originally Posted by jmc link=1217679658/0#4 date=1217729715
    Dave,
    What I do for my 2 group La Pavoni is filter the water as it comes from the tap, then put it into the bottle. Above counter water filters can be found online ( PM me for the people I use ) for around $100.
    Ooops, sorry Dave..... :-[

    Id always opt for the most simple method mate and what "jmc" has outlined makes a lot of sense. Have a look at the "Bombora" website and check out all the options available from just one distributor. Theres a heap of ways to do this without adding unnecessary complication....

    Mal.

  7. #7
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    Re: Flojet pumps

    morning Dave

    what sort of filtration are you intending to use
    what is the minimun pressure required for the filter

    in most cases the procon will draw water from a tank through a filter, depending on the micron size of the filtration

    graham

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    Re: Flojet pumps

    Hey Graham,

    Standard 0.5 micron Aqualife water filter. The procon pump will not pump from the water filter, which is why Im looking for solutions.

    Cheers,

    DS

  9. #9
    Mal Dimal's Avatar
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    Re: Flojet pumps

    Hmmm,

    Just thinking mate (yeah I know, thats dangerous).... Why not just use the mains pressure to push water through the filter system into the plastic container/water bottle, say from the water spout in the sink or bathroom and then transfer the refilled container/bottle back close to the espresso machine?

    Seems like a lot simpler way of doing it and when youve completed a refill, just roll up the hoses for the filter system and put it away in the cupboard. No need for any extra pumps or complication, just a cleverly arranged set of filters and hoses.... 8-)

    Mal.

  10. #10
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    Re: Flojet pumps

    I think Dave wants to just set it up and forget about it without having to mess around. Makes sense to me though Mal

  11. #11
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    Re: Flojet pumps

    NPSH (Net positive suction head) is the reason you cant get any water into the pump past your filter. Below is the simple version.

    10m is approx atmospheric pressure or about 14 PSI

    Pumps dont suck !!! Atmospheric pressure is the only thing that makes water enter a pump. From this we need to look at the losses from the rest of the system that prevent that from happening.

    Pressure losses across the filter are the big problem especially when dirty. A 5 micron filter will drop about 1m but a 0.5 micron wil drop more like 10-15m

    Pipe Friction and valve losses need to be considered, also under sink tank (say an extra metre), the pump itself requires some left over as well including a safety margin (2-3m). There is also a correction for temp but it doesnt matter much unless you are getting above 40 C.

    So in a basic system with 10-12mm pipe or hose and a 5 micron cartridge it will work but a 0.5 wont.

    NPSH is a lot more involved than this but basically the less restrictions on the suction side of a pump the better. The only way to run the 0.5 filter is to fit it to the output side of the pump and maybe a course one on the inlet of around 20-30 micron.

    best of luck.

  12. #12
    Mal Dimal's Avatar
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    Re: Flojet pumps

    Well actually,

    The pumps found in most espresso machines, be they reciprocating or eccentric vane types, are positive displacement pumps and will indeed "suck" through a filter by virtue of evacuating the air in the pipeline. Although, I wouldnt try doing this at both a negative head AND through a filter.... Just asking for trouble for sure. If you had a means of easily bleeding the pump to ensure that the incoming water line from the filter was 100% full of water at all times, this situation would probably remain ok but might require the fitting of a non-return valve upstream of the filter to ensure the water didnt drain out of the line.

    Not all pumps are happy to operate in this way of course as some of them rely on water to lubricate the pump seals and without it, will just sit there happily turning the seals into a molten mass. Not very pretty. Procon pumps will certainly be happy to operate this way, within specification but Im not sure what sort of -ve head most Vibe pumps (found in espresso machines) are rated at. No doubt this sort of info could be gleaned from the Ulka or Fluid-o-Tech people.

    As you point out though "beanflying", much better to maintain a positive head at the inlet of a pump and avoid all risk; that was why I suggested a simple arrangement to use mains water pressure to supply the prerequisite positive pressure. Still dont believe that a feed pump arrangement is necessary to provide this.

    Cheers,
    Mal.

  13. #13
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    Re: Flojet pumps

    Hi Mal and all,

    Repeat after me "Pumps dont suck" *:) Positive displacement pumps such as sliding vane or impulse piston pums only pump fluid and are limited by atmospheric pressure.

    One of the benifits of the Procon vane style of pump is that they move the water constantly and have a low NPSHr (NPSH required) this translates to a greater ability to cope with higher suction lifts etc.

    Rubber diaphram (flojet) pumps or UCLA type of pumps will suffer badly when you place restrictions on the inlet side of the pump as the outlet performance will degrade. The rubber diaphram will not deflect as much so you lose volume for a given RPM. In the case of the UCLA the plunger will not move as much (based on there performance curves). In a true piston pump this is not the case as they have rigid valves and pistons so for a given RPM you get a given volume unless you have exceeded the NPSHa (NPSHa).

    When NPSHa is less than 0 (normally less than 1-1.5m is considered the safe lower limit) you get cavitation. Cool sound like marble going through the pump but destructive *:o

    For a system to work

    NPSHa >= Atmospheric pressure (10m) + Water Level (- if under bench) - Vapour Pressure (not that important for cold water) - Pipe and Filter Losses - NPSHr (what the pump needs)

    NPSHr is not listed for any of the common pumps used in espresso machines but the procon will be in the order of 2-3m based on similar pumps. The UCLA will be more but it is anyones guess.

    Welcome to pumps 101 *::) When I was taught this it was nearly a full day so feel free to be confused *:-?

    15 years in the industrial pump trade BTW :) Pumping lots of good and really ugly stuff :P

  14. #14
    Mal Dimal's Avatar
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    Re: Flojet pumps

    25 years in engineering in heavy industry, mining and petro-chem "bf"... I know pumps dont suck but they (positive displacement types) do evacuate the inlet side of the pump and providing the pump is capable of being primed from a dry state without harm, then they can "self-prime" quite well, even with a filter in the way. As are you, I am also drawing from personal experience, not theory alone....

    Mal.

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    Re: Flojet pumps

    when we set up mobile coffee units we

    * install a non return valve near the pump and another at the tank
    (generally find these units do not seal 100%, so 2 units gives us more protection

    * keep supply line to a minimun length

    * 3/8 tubing or braided hose minimun internal size
    (under this decreases the flow causing pump vibration)

    * 5micron (absolute) water filter (culligan GW)
    this is generally the finest filter used, and recomended these days for coffee machines
    we used to use .5micron filters for mains connected machines but the cartridges use to block very quickly
    (if you visit the Aqualife site you will find the water filter they use for coffee machines is 5 micron (absolute) and .5 micron for drinking water

    * on some of the machines which have lazy pumps, we fit a 5 micron (nominal)

    * in most instances the pump bypass will need to be readjusted


    graham

  16. #16
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    Re: Flojet pumps

    Just out of interest are you fitting them to the outlet side (best choice) of the pump or the inlet side ( [smiley=evil.gif] side) of the pump?

    Reason for the readjustment for others info too is that the pressure loss past the filter ads to the pressure the pump must generate at a given flow rate and this varies slightly with pressure. This also will show as the filter clogs more in lower pressure at the head so change the filters often :).

    Last couple of things on procons or similar if they are a model with an inlet screen fitted make sure it gets degunged once in a while and dont let it run dry or try and prime it for more than 20-30 seconds at a time or the seals will get damaged by the heat generated :(

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    Re: Flojet pumps

    as the majority of machines have internal pumps the filter is fitted before the pump(also protects pump)

    when we inital setup, we prime the filter and system with mains water supply. this way everything is wet on start up

    graham

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    Re: Flojet pumps

    To answer the original Question, have a look at a large caravan equipment supplier, they will normally have small no name pressure pumps at around the $80 mark, though I am not sure if there are any that will run on 240v, most would be 12v DC

    if all you need to do is have a pump to help the water through a filter and be able to lift it some distance (say the bottle is under the bench) then look at car fuel pumps as well, once again 12v but compact and robust


  19. #19
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    Re: Flojet pumps

    Hi Sunbeamer,

    it is possible to get 240V flojets but they are fairly expensive ($300+) and there is some additional problems with feeding one pump with another, you can fit a pressure regulator but that is more expense and fuss. Best solution is to use the 5 micron filter and pesonally place it after the pump rather than in the suction line and that wil sort it.

  20. #20
    Senior Member robusto's Avatar
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    Re: Flojet pumps

    Pressurised water systems on caravans, boats, usually consist of:

    water in a container at atmospheric pressure.
    Hose to a flojet style pump with pressure valve
    Hose from pump to a filter
    Filter to taps.

    When tap is opened, in-line water pressure drops, and a switch on the pump automatically activates the pump until the tap is closed again.

    The simple solution here is to go:

    Water bottle - pump - filter -coffee machine.

    The pumps draw about 7 amps at 12VDC, so sould need a heavy-duty transformer from 240V AC.

  21. #21
    jmc
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    Re: Flojet pumps

    I PMed this to Dave last week but thought I should put it up for anyone who can use it.

    Just to remind you, my machine is an Aurora Euopa single group spring lever. No pump needed ( it does have an autofill circuit ) but it needs over 2 bar to refill the boiler and I cant plumb it where I live.
    I went to a camping R/V place in Ferntree Gully and bought a 12 Volt caravan pump.
    Cost $ 130. Brand Shurflo. Model 2088 422 144.
    Went to Bunnings and bought a HPM Garden light transformer # RGLTR60 - 240v ac down to 12v ac. I think $43.
    Went to Jaycar and bought a rectifier CAT. NO. ZR1324 and the appropriate capacitor ( to smooth it). Under $10.
    The rectifier and *capacitor change 12v ac to 12v dc.
    Screwed it all on a piece of board so it wouldnt move around.
    Connected the 240v ac power from the autofill circuit to the 240v transformer and away it went. i.e. when the autofill circuit decides the machine needs more water it sends 240v to the solenoid and this is where I connected in my outlet to the transformer. *So the transformer only gets power when the autofill circuit activates.
    There are caveats. Im not an electrician. The transformer is way undersized for the pump but cycles so infrequently that it doesnt even begin to get warm.

    The cheapest Flojet I could find was $300 +

    John



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