Why the Washer ?

Many of the classic ca 1950s bulb rectal syringes have a whitish bone washer between the nozzle and the bulb.

For example:

https://img.techpowerup.org/191025/bulb.jpg

What is the purpose of the washer? It seems completely unnecessary to me.

The soft slightly compressible washer improves the seal between the nozzle and bulb which typically had lousy machining/injection molding tolerances.

@SwitchableSusie

Susie, all the dozen or so washers (or shields as called on the box) I've seen have been made of machined bone and are hard, very like Ivory.

They are not at all soft or flexible. Also, they are usually lose on the nozzle.

Obviously they felt there was going to be an issue with leaks if they didn't do it.

At one time, the standard fittings required a washer for any fitting that was not tapered. Maybe it was do that first and find out if you have leak-proof fittings later.

I always thought it was to prevent leakage.....sorta like the shield found on douche bulb syringes.

It is a gasket to help, hopefully, to prevent leaks. Garden hoses use a washer for the same reason.

Back in the '50's our family fountain syringe had a black rubber washer that provided a leak proof seal between the nozzle and the threaded part attached to the red ribbed hose. Memories

Interesting that I came across this post now. I have a 8oz blue bulb with a black washer which i am using as I post this now. It always leaked and I Krazy Glued it to the bulb and put tape around the pipe which completely sealed the bulb from leaks. I posted about this a couple of days ago.

The 'washer' I referred to in the OP is NOT any form of gasket. It doesn't seal anything and is a loose fit on the nozzle.

The comments about rubber gaskets on syringes with fine thread fittings are valid. In those cases the gaskets are to seal the joint between the nozzle and connector on the hose, because the thread is not tapered as with a standard pipe thread. The threads are usually NSPP... National Standard Parallel Pipe... which require gaskets.

The washer I referenced is of hard material (bone) and can not be compressed to form any kind of a seal. Also, the white washer is only used only on syringes with nozzles that push into the bulb opening, not with screw on nozzles.

I'm certain they are not gaskets and suspect they are 'shields' to prevent any oil based lubricant from getting onto the bulb and causing the rubber to perish, but can't confirm that theory. They may also be to prevent the lube from getting onto the rubber where it'd be harder to remove than from the bone

By luck one time i found a beautiful black enema nozzle in the drugstore and i bought it for $2 the only problem was that it leaked because the female end of the nozzle did not fit the male end of the enema connector.

the perfect solution for me was to wrap the male end of the threaded connector with teflon tape and it worked perfectly.

from time to time i had to change the tape for cleaning.

Nothing to do with enema equipment, rather more to do with things you have that you find you dont need, i repair tractors, and one example of this is in a head gasket set for one range of tractors there are 4 flat steel washers, there are NO washers that size involved, bit sad really that someone is buying washers and putting them in kits for the last 40 years, wonder if i told him, would he be upset ?