Help with suction nozzle

[OregonBob]

Hello, I am building a small backpack style dredge and it's going to use a suction nozzle. I'm going to make that as well it's going to be a 1 1/2" hose going to the sluice.

What size port do I put in the suction nozzle where the pressure line enters the nozzle? The pressure line will be 1" but I think it needs to get smaller for a jet. Like I said.......I THINK it needs to be Thank you for your time and trouble. Bob

[russau]

Hi Bob! on a 2 inch venturi nozzel the port for it is approx. 1/2 inch,so for a 1 1/2 inch venturi nozzel id say 3/8 or 7/16inch opening. and if your handi makeing things, id try to make 3/8 or 7/16 in opening in a cone shaped washer. my reasoning for this is, if you just use a flat washer, when the water hits the flat surface it,inessence,bounces all over.where as if it is tapered like a cone it forces the water to be more of a concentrated spray rather than a blast of water. either one would work but i played around with this a few years back when makeing a device and decided to use this cone shaped venturi for myself. good luck and let us know what you did and how it turned out.

[OregonBob]

Thanks I am handy and I will make it tapered. I am making it from pix I see online and theres not to many good ones. I was going to use EMT for the pipeing 1 1/2" and 3/4" or 1/2" not sure. Never built a suction nozzle before.....never even had one in my hands but im sure I will figure it out. thanks again and i will let you know how it goes.
Bob