Jamie McGrath
Member
- Joined
- 3 Apr 2014
- Messages
- 145
Is there any problems reducing filter hoses from 25/34mm down to 16/22mm? Has anybody done this?
The reason I want to do this is ive just bought a filter and it has the 25/34mm tubing. All my existing spray bar and intake pipe are for 16/22mm. I dont want to buy a new spary bar and intake pipe for the large tubing, im also struggling to find somwhere that sells it all.I am sure lots people have done that but, it is obviously not recommended as the flow rate will be considerably reduced.
I assume you are talking about a high flow filter, if you want to keep the flow then you need the inside diameter to be 25mm.
The suction or feed side will need to be 25mm but you could split the return into 2 x 16mm.
Did you measure actual flow rates?You get more flow through the narrower tube to compensate for the reduced diameter but that's to be expected
Now repeat the experiment with a pump that is already working at max capacityYup. Try it yourself
If filter is running at 2 litres/min & tubing is changed out so that flow is now 1litre/min ie change in speed of flow, how can this not affect the volume of water displaced (ie "moved" ) in 1 minutechanging the tube size only affects the speed of the flow and not the overall volume of water displaced.
what are the units of velocity then?Litre measures volume and should stay the same. But velocity will change.
Righto....with standard magnetic drive pumps they will suffer if you reduce the flow, as if the impellor is no longer rotating at "full speed" due to reduced flow, it will slowly get demagnetised. Once the impellor starts getting demagnetised, the noise will increase and impellor will be prone to stalling.
Most decent filters, this is from JBL e1501, state that you should not reduce the flow too much.
View attachment 85748
This is another interesting point because if you look at an impeller the blades do not slant in a certain direction compared to, say a motorboat propeller. This is because it is actually working on a centrifugal principle, which relies on creating flow through kinetic energy. This is why kinks, blockages etc. are so bad for it.pumps are generally designed to push against pressure rather than pull against it