Stupid question about plant sprayers

Does anyone know why my plant sprayer stops spraying when it gets down to half empty?

It is just a standard 1 litre indoor sprayer. Actually, I was using it to spray weedkiller ('cos I couldn't get a faux-Killaspray to spray). It worked like a dream for the first half. Then I couldn't get the second 500 ml of expensive weedkiller out -- I poured it into my red watering can instead, but that's a less efficient way of killing weeds.

Is it something to do with a drop in pressure? I never did understand physics. Yet I have various nozzle-spray kitchen cleaner containers that work right until the last few drops.

I have rinsed out the tube and nozzle to make sure there was no grit.

Alternatively, how do you make those Killaspray things spray? I took mine back to the shop and got a refund. It wasn't Hozelock, it was a cheap copy.

Ta.

 

Are you referring to the trigger type sprays or the pump up ones?

If its the pump up ones you need to pump it up a bit half way through spraying, if it the trigger type you need to keep it upright.

 

I was referring to a trigger spray. I did keep it upright -- as I say, it was fine for a while.

Previously I'd tried a pump one and couldn't get anything out!

 

It's probably a inefficient pump unit on the spray not capable of giving enough lift once the liquid level drops below the half way mark, when the spray is full the weight of the liquid fills the tube up to the pump once halfway it has to lift it(a bit like sucking on a straw the lower your drink gets the harder you have to suck) Nowt else for it but a new spray.

 

I cant understand a pump up sprayer not working, I can only guess but I would say either the nozzle was blocked or maybe you didn't tighten it up hard enough and there fore there was no pressure building up in the tank.

As to the trigger spray, they are OK for small areas but hard work to use on anything of a reasonable size.
Also the things do appear to be designed so you cant get a fair amount of the liquid out at the bottom.
I guess this means they sell more of the stuff.