Oil filter kit or similar

  • Thread starter Thread starter Erivaj
  • Start date Start date
The other thing to be aware of with filters, especially the fine media type, is to make sure they have a bypass circuit. If the filter media gets clogged with crud and doesn't have a bypass valve, you could end up with no flow at all.  Some oil filters have a built-in bypass valve, others rely on a bypass elsewhere in the oil feed system.

As far as I recall, Bernoulli had a lot to say about the venturi effect, but not much about pressure drop through filter media.

Cheers,
Cam
 
G'day Simon

I won’t presume to lecture anyone on engineering principles (I'd be crap at it anyway), nor do I want to get into an argument, but happy to bounce opinions back and forth and learn from people smarter than me.

Anyway, since you asked: What is a Venturi if not a restriction? Here is my understanding…

As far as I’m aware, a Venturi is not a restriction. It’s a gradual change in cross sectional area of a pipe, with entry and exit cones that have quite shallow angles specifically chosen to avoid flow restriction.

A filter mesh is an abrupt change in flow conditions - which is a restriction.

With relevance to this oil filter discussion: when static pressure drops through an abrupt change in flow conditions, it doesn’t increase again after the restriction. There is a permanent reduction in static pressure.

When static pressure drops through the throat of a Venturi, it increases again (at the expense of velocity pressure) as the fluid passes out through the exit cone. So there may be bugger all total pressure drop through a Venturi, and therefore bugger-all resistance to flow.

Cheers,
Cam
 
The one I use (see link in previous posts) has a bypass valve.

Important also: check that the oil flows the right direction. There is no use of a bypass valve, if the oil-flow comes from the side that pushes the bypass valve into its seat...  ;)
 
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