9/19/2023 0 Comments Venturi dredge pump![]() Turns out it has way better pressure than I thought it would, and I will be able to run a surface box on it if I want to. I made this set-up from stuff I had lying around or bought cheaply, didn't have much faith in the pump, as it's a self priming type, Onga brand. might be a bit of overkill but it might just do the job at a lot lower revs. I have got one of the HP500's fitted to a 9hp ready for a try. :-) - It has been very interesting seeing how the 300/350/400 pumps go on the 7/8th veturi. Having the Proline agency here in NZ gives me the flexibility to be able to try out the Proline range of pumps on my old 5" 'gumbooter' as I call it. ![]() Talking with Jeff Kuykendal from Proline - he told me his dad worked for Gold King and this pump was known as I think he said the 20 by 15. They are a good little pump and have a rating of around 55psi. A guy here in Christchurch NZ made some patterns off one and produced them under the name 'Swimjoy'. The second pump - the blue one is a copy of the 'Treasure Emporium' made and sold by 'Gold King' in the states a few years ago. I did try a twin impellor on this dredge - no success. I have one of the twins pumping water to 95 metres albeit not a great flow at this height but a flow never the less. ![]() The single impellor models have a purported pressure rating of 70psi and the twin impellor twice this at 140psi. The high pressure fire pump honda lookalikes that some of you have are a good pressure pump but dont have the volume to back this pressure up. I had a keene P180 on it - it worked but not real good - you had to limit what was going up the hooter or it could stall - The pump in the picture with the two pumps - the first one is a chinese 2" cetrifugal 'water mover' - they have a 25psi rating at 3600 revs - I import these pumps in from China and sell them here in New Zealand along with a bit of other gear. I am now powering it with a 'Proline' HP300 pump - it is able at its top end to deliver 280 gals at a pressure of 55psi and running this through a 7/8th venturi gets it going good. The gain was around 10% and at the top end it was quite a bit when the nozzle was getting to around 5 or 6 foot down. Hi guys - It is just a single suction nozzle venturi - i found that by using one pump as the lift and feed to the second i was able to obtain full pressure from the second high pressure pump - nothing lost in the lift of the water to the pump. Good luck to you all & a very merry xmas & a prosperous new year. Nuggy, How you going mate? I was going to go for a dredge this weekend but the weather that has been fine for months has decided to 5hit itself this weekend. ![]() You will notice in my above pics how much lower the box is to the water when it is operating & full of water & material compared to the pic of the dredge just sitting in the water before operation. Also as your operating & your box fills up with water flowing down & the riffles getting loaded up with material, this will affect the balance as well & you will need the adjustments to be easily made out in the field as well as being able to alter the tilt of the box. I actualy wonder if yours isnt too low & by the looks of your frame you are going to mount the motor/pump at the back? If not then I think you will have to slide your box back quite a bit & as has been said you will need to find the sweet balance spot. Probably won't spend any more on it, as I'm more used to 5 or 6 inch dredges and moving more and bigger material. The dredge especially the pump goes better than I thought it would. Yes I have used it - On my thread "Let Dredging Begin" is a dark photo showing it floating in creek. This type of box is not as good as the surface type for catching fine gold, but it takes less power to run, as not trying to lift material so far above surface. That's why the sides are much higher too. The back pressure slows flow to let heavies drop out. Different to the others shown above which are surface boxes, this one needs to be partly submerged, about halfway ( a semi-surface box we call them here). Hi Jason, this box was once on a six inch venturi dredge! Used as an underwater box it had a lid on it then.
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