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UK Window Cleaning Forum => Window Cleaning Forum => Topic started by: dudek on July 18, 2007, 07:20:53 pm

Title: Whats the physics behind microbore
Post by: dudek on July 18, 2007, 07:20:53 pm
I have heard people raving about microbore and how it can save water but can anyone explain the principles behind these water savings?

I'm struggling to see what a diffrence it can really make as surely the only two principles that matter are the pump pressure and the spray from the brush?

so how can microbore really have a bearing on the water consumption side of things?

Can someone please enlighten me as to what i'm missing ???

Dudek
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 07:40:19 pm
Think its called fluid dynamics where the water acts as a semi-solid/fluid within the pipe, eg try sucking/syphoning water through a straw and a hose, smaller diameter is easier to suck because there is less diameter. Oppositly lager bore neeeds more pressure for the volume of water. So you need a fire enngine to pump large quantities through a 5" bore pipe but only out small pumps for smaller bore. It gets complicated the further you go with fluid/hydraulic  friction from the pipe and the water itself slowing it down. So for the pressure to be the same over a longer distance you need a bigger bore that reduces to a smaller one or  hence micro bore, which means you restrict the flow and hence save water.
 :o blimey even I dont understand that lot.  ;D ;D
Title: Re: Whats the physics behind microbore
Post by: Alex Gardiner on July 18, 2007, 07:43:35 pm
Hi Dudek,

Microbore is really one of the best things that has happened to WFP. We have been using it now for 5 years and would really never consider using anything else.

The two things that really matter when using a WFP system are the flow rate of the pump (not the pressure as this just tells the pump when to switch off) and the flow rate from the brush head.

The main benefit of microbore is that it is easier to use, reel up, it doesn't get caught up as much, doesn't kink as much, is much lighter and you can fit twice as much on the hose reel.

A side benefit that we discovered when we started using it is that helps control the flow rate. The flow rate from a pump can be anywhere from 4-8 litres per minute, which is actually too much for general use. Standard 1/2" hose will slow this up somewhat, but microbore will restrict this even further due to the drag factor from the inner sidewalls of the hose. The other thing that affects flow rate is the size of jets that you choose on the brush. We have found over the years that 2x 2mm jets suit WFP purposes well. All of these will reduce the flow rate to about 1.5-1.8 litres per minute from the brush head if you are using 100m of microbore.

The above flow rate is about spot on for the average WFP'er.
Title: Re: Whats the physics behind microbore
Post by: dudek on July 18, 2007, 07:47:48 pm
I will go along with all of that its quite hard to get my around but i trust what you have said.

Thanks
Title: Re: Whats the physics behind microbore
Post by: Alex Gardiner on July 18, 2007, 07:55:15 pm
It's one of those things that until you try it you will never know!

5 years ago I had the idea of using 6mm ID  re-inforced hose for my work as I realised that it would be lighter and I could stop linking two 50m reels of Tricoflex together on my commercial work. I rang around all the major suppliers and most were not interested in the idea, so I sourced some from a hose extruder directly, (This reel has just been 'retired' only last month and we still use the same supplier for all of our hose) after using it for just one day I immediately switched all of our vehicle set-ups to it, it really does make that much of a difference to your days work.
Title: Re: Whats the physics behind microbore
Post by: Londoner on July 18, 2007, 07:58:06 pm
Also, the amount of water held on the pipe is a lot less so less water has to be pumped through to fill the hose before water starts coming out of the other end. If you have a trolley thats important.

Second, if you imagine a hose on a reel. Trapped air will rise to the top of each coil in turn and sit there. To clear that air out you have to wack up the pressure enough to force all the air through all the loops. With a half inch hose thats a lot of water wasted to clear the air locks out.
 Using microbore the air just seems to push through by itself a lot of the time without the need for special airlock measures.

Yellow half inch hose has a much thinner wall in relation to its diameter. This makes it prone to snagging because it is too flexible. Microbore is more "solid" and therefore snakes around obsticals. This saves time generally but since the water is on while you are unjamming your hose water is being lost as well.
Title: Re: Whats the physics behind microbore
Post by: NWH on July 18, 2007, 08:00:35 pm
I have 100mtrs of microbore and it keeps blowing presure switches and flo cntrls WHY.
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 08:02:33 pm
Maybe the column of water pressure is more than the pump is intended for, try cutting 20m off. Or get a bigger pump or higher rated pressure switch.
Title: Re: Whats the physics behind microbore
Post by: Alex Gardiner on July 18, 2007, 08:07:57 pm
NWH - are you using Shurflo pumps?
Title: Re: Whats the physics behind microbore
Post by: NWH on July 18, 2007, 08:11:10 pm
Yes i use shurflo pumps and eco-flo,my system was working with no problems for 3-4 months then all of a sudden i get this problem.I was told that over that time the switch is getting a hammering till in the end it gives up the ghost,thing is it`s blowing the flo cntrl as well as the switch.
Title: Re: Whats the physics behind microbore
Post by: Alex Gardiner on July 18, 2007, 08:30:43 pm
We've always used Flojet pumps with microbore and have never had a problem with them - it might be worth switching pumps?
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 08:40:00 pm
Flojet for me.   :) Both are USA  (probably made in China)
Title: Re: Whats the physics behind microbore
Post by: Clive McDonald on July 18, 2007, 08:53:15 pm
I was sold mini bore.
Are there any pros and cons with this or is it somewhere in the middle?
I'm happy with it, but I don't know any better.
Title: Re: Whats the physics behind microbore
Post by: m.b.s. on July 18, 2007, 08:54:02 pm
yes but with a flo jet 60 psi and 60 meters of 6mm microbore hose do you still need a varie  stream controller some  say yes some say no if yes why if no also why. mabe a good pole topic what do you think ???
Title: Re: Whats the physics behind microbore
Post by: jeff1 on July 18, 2007, 08:58:57 pm
I had a 32 ton lorry run over mine today  :o It never even stopped the flow and there was no damage to the hose at all. ;D  there is some good phisics for a microbore hose for you. ;)
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 09:15:40 pm
Jeff
Maybe the "lorry test" should be added to the spec of all hoses.

Switching to Algarde silicon type 4mmID was the smart move for me in the last 10 years. But it wont do 100m unless you use the 6mm dia.
Title: Re: Whats the physics behind microbore
Post by: NWH on July 18, 2007, 09:24:46 pm
So why is the cntrl being blown,how can that be down to the pump.Some people have been running these pumps for years with no problems.I am being told that it`s down to the microbore.
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 09:28:09 pm
Ring these and ask for an explanation, tell them you are thinking of replacing your pump- ask for a catalogue while you there, loads of stuff, you could ask for Stuart in the stores.  http://www.dualpumps.co.uk This is the company most of the supliers use and the pump they use is the Duplex II- two piston By pass pump.http://www.dualpumps.co.uk/pages/diaphragm_roller/disphragm_roller_subs/flojet_electric_driven_pumps.htm its got a by pass  :)

I quite like the look of this wheelbarrow tank that I have just seen  http://www.dualpumps.co.uk/pages/new_prods_07/newprod_details6.htm#wheelbarrow
Title: Re: Whats the physics behind microbore
Post by: m.b.s. on July 18, 2007, 09:29:13 pm
why is it down to the microbore nwh
Title: Re: Whats the physics behind microbore
Post by: jeff1 on July 18, 2007, 09:32:13 pm
So why is the cntrl being blown,how can that be down to the pump.Some people have been running these pumps for years with no problems.I am being told that it`s down to the microbore.
If the switch was a machanical one then the answer would be Yes! its taking a hammering, but the echo like the varistream are electronic switching and for there to be a fault in there you may have had a faulty one from the start. or the fault lies some where else.

Jeff
Maybe the "lorry test" should be added to the spec of all hoses.

 
I don't think 95% of hoses would stand up to this test, I must admit I held my breath when I seen the lorry coming up the road, I have had cars run over it for a past time with no affect at all.
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 09:38:08 pm
You can usually feel the shock wave right up the pole as the lorry goes over it- strange feeling.
Title: Re: Whats the physics behind microbore
Post by: jeff1 on July 18, 2007, 09:40:32 pm
You can usually feel the shock wave right up the pole as the lorry goes over it- strange feeling.

FEEL IT  ;D ;D I seen the shock wave coming up the road. ;D ;D
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 18, 2007, 09:41:57 pm
Oh the wheel barrow tank 125L back a few posts may not be that good it seems its £399  :'(
Title: Re: Whats the physics behind microbore
Post by: NWH on July 18, 2007, 10:02:54 pm
What do williamsons recomend you use as far as hose goes.
Title: Re: Whats the physics behind microbore
Post by: *foxman on July 19, 2007, 02:19:54 am
I have 100mtrs of microbore and it keeps blowing presure switches and flo cntrls WHY.

You probably have 6mm hose that has issues with some setups, move up to 8mm and it should solve any probelms and still have all the benefits.
Title: Re: Whats the physics behind microbore
Post by: JM123 on July 19, 2007, 12:00:30 pm
or alternatively just get a varistream and bypass the pressure switch. 
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 19, 2007, 04:57:34 pm
I agree, you can have pressure switches set up to various pressure, I find a simple by pass will cope with any pressures.
Title: Re: Whats the physics behind microbore
Post by: JM123 on July 19, 2007, 05:02:21 pm
Hi Jeff

I mean to electronically bypass the pressure switch, when you use a varistream the pressure switch is disconnected.
Title: Re: Whats the physics behind microbore
Post by: Jeff Brimble on July 19, 2007, 05:36:46 pm
Thanks. For many years I used pumps without the option of pressure switches and got round the problem with a small external by pass which still serves me well. New innovations like the Variflow and an internal by pass fitted to the pumps alleviate the need for pressure switches. As Alaex said previously you can happen on the right balance combination of flow versus pressure by using the correct diameter hose matched up to the length. Which is what I did using the small 35psi pumps. Its the simple method. The Variflow and internal bypass is the modern method. Mine costs me £4
Title: Re: Whats the physics behind microbore
Post by: NWH on July 19, 2007, 07:31:53 pm
With the varistream when you unplug the pole with the pressure switch being disconnected does this mean that the pump dosen`t cycle,what i`m saying is does it in effect turn the pump off and then turn on again when you plug pole back in.