Louvers, holes and "slits"?

D60

Joined
Nov 6, 2017
Messages
7,833
Location
Colo
Recent threads have me interested in how the ID tube is stamped in filters. I happened to look at this TL24651 -- an inexpensive Purolator I often use on Ford modulars (and allegedly exactly the same as the red cans).

I don't believe these are a louver per se because they're not a single piece angled out but more of a channel stamped that appears to have an opening at either end.

Still, the slit at either end appears quite small, but I guess there's a lot of them so it can probably flow enough.

What's the general opinion on this design? Sufficient?

If results count for anything, I've run quite a few of these with no problems.

Viewed from top:
20250519_150431.webp

Viewed from bottom:
20250519_150413.webp
 
I’m not a fan personally. I’d prefer the holes over the louvers. However, I have run Fram endurance filters with louvers. I also use fleetguard filters with louvers without issue. So with that being said, I guess my opinion is mixed based on how the louvers look.

IMG_8083.webp


IMG_1693.webp
 
Last edited:
Recent threads have me interested in how the ID tube is stamped in filters. I happened to look at this TL24651 -- an inexpensive Purolator I often use on Ford modulars (and allegedly exactly the same as the red cans).

I don't believe these are a louver per se because they're not a single piece angled out but more of a channel stamped that appears to have an opening at either end.

Still, the slit at either end appears quite small, but I guess there's a lot of them so it can probably flow enough.

What's the general opinion on this design? Sufficient?

If results count for anything, I've run quite a few of these with no problems.

Viewed from top:
View attachment 280130
Viewed from bottom:View attachment 280131
Those are louvers, and they look absolutely awful.
 
Ok thank you all! I wouldn't consider that a typical definition of a louver but now I know for filters the term applies to this design.
 
I don't believe these are a louver per se because they're not a single piece angled out but more of a channel stamped that appears to have an opening at either end.

Still, the slit at either end appears quite small, but I guess there's a lot of them so it can probably flow enough.
"Slits" are louvers that are are not very open. A center tube is either a metal tube with holes or louvers, or it's a nylon Ecore cage design.

Prime example when louvers become "slits'.

1747714927113.webp
 
Ok thank you all! I wouldn't consider that a typical definition of a louver but now I know for filters the term applies to this design.
What's your definition of louvers? Anything similarly shaped is defined as a louver, even if it's on a rear window of a car.

1747715403576.webp


Images of louvers: LINK
 
I'm having a hard time understanding any concept of a Louver in a core.

Mainly because isn't oil pressure the determining factor and how oil is pushed through the element.
What is the purpose of a Louver in a core? Does this create cooling? Or does this help enhance the flow?

Again doesn't oil pressure dictate how oil passes through an element regardless of louvers holes slits whatever. Thank you
 
A guess is Hastings/Baldwin started the trend. Theirs are different shape. I suppose it was some kind of advantage as there are so many of them, for marketing purposes. I don’t like them because the edges of the holes are rough. Unless the louvers are washed well, don’t trust that particles won’t come off until things stabilize.
The cleanest holes I’ve seen in my box of unused oil filters is the Microgard regular and the Toyota. The MG is made in India in the two sizes I have, and looks the best.
 
They are louvers in the OP, it doesn't matter that some are pointed in opposite direction from the others.

Louvers are popular because they are easy to make in a continuous forming operation. That makes them very cost-effective.
Also, because technically no metal is being removed, they are less likely to generate debris and unwelcome passengers in the center tube (i.e. no "hanging chads" like a punch-out operation might give). If you have a louver that doesn't open as far as it could, it doesn't matter because you have hundreds of levels of redundancy.

Many fleetguard oil filters use louvers. If Fleetguard trusts them, I do.

Also, because louvers are so many and so widely distributed vs having a small number of larger holes, the flow might be more uniformly distributed through the media. This would enhance media life and capacity if true.
 
They are louvers in the OP, it doesn't matter that some are pointed in opposite direction from the others.

Louvers are popular because they are easy to make in a continuous forming operation. That makes them very cost-effective.
Also, because technically no metal is being removed, they are less likely to generate debris and unwelcome passengers in the center tube (i.e. no "hanging chads" like a punch-out operation might give). If you have a louver that doesn't open as far as it could, it doesn't matter because you have hundreds of levels of redundancy.

Many fleetguard oil filters use louvers. If Fleetguard trusts them, I do.

Also, because louvers are so many and so widely distributed vs having a small number of larger holes, the flow might be more uniformly distributed through the media. This would enhance media life and capacity if true.
You see the ragged edges, and this is only by eye which is not microscopic. Especially on louvers not opened well. No holes have edges like this.
There was a not fully punched hole in a Pentius filter, and board experts decided it wasn’t going to fly off. But those chads or almost chads can be easily seen, and I have never seen one except that example.
 
If you have a louver that doesn't open as far as it could, it doesn't matter because you have hundreds of levels of redundancy.
There's still a point where they can be too choked off - don't "trust" them because there are many. As discussed in many louvers threads, the person buying the filter needs to made a visual determination if the louvers are opened up enough or not. Like the two examples in post 10 and the example in post 17, it's pretty obvious which center tube has sketchy louvers and should be avoided.
 
I'm having a hard time understanding any concept of a Louver in a core.

Mainly because isn't oil pressure the determining factor and how oil is pushed through the element.
What is the purpose of a Louver in a core? Does this create cooling? Or does this help enhance the flow?

Again doesn't oil pressure dictate how oil passes through an element regardless of louvers holes slits whatever. Thank you
Choked down louvers are going to increase the dP across the media & center tube, which will push the dP closer the the bypass valve setting. The PD oil pump is going to still try to force lots of oil through the filter, but If the louvers are really choked down, it's essentially like blocking the oil flow and the dP can then be high enough to put the filter in bypass most of the time. Nobody wants a filter operating in bypass that much.
 
Back
Top Bottom