Model 625 Hand Dredge Body with matching Model 625 Hand Dredge Discharge Valve set up including manually adjustable 90 degree elbow in black, ready to accept 1 1/2" Plastic Pipe fittings.
The Model 625 Hand Dredge, works much like a typical recreational suction dredge, only the suction is Immediate Vacuum Response (IVR) and not dependent upon a power jet venturi's impeller produced siphoning vacuum that's driven by the mechanical force of an artificial gravity (see hydraulic mining monitor) type water pressure forced angularly into the dredge hose cavity. The convoluted cylinder bellows "HG Power Plant" is reinforced from inside and out making the operation more like a "rocking" piston pump. Best of all, it's ported to effortlessly pass 1 1/2" diameter cobbles, or attach the large 3 1/2" inner diameter, 1/2" mesh seive nozzle for suctioning and pumping massive amounts of pre-classified dredge material with fine gold into a free flowing sluice or a side loading bucket. Effortless operation makes all day GOLD hand dredging possible.
Get suctioning fast, add piping, fittings, hose and other accessories from the check list below. Click add to cart to automatically preview the price. Optionally "UN-BUILD" the dredge by selecting check box's with a negative value.
With a single elongation stroke of the pump, these hand powered suction separator dredges are capable of creating enormous suction at the nozzle end due to their sealed no leaks construction. What about wear and tear? No problem, replacement parts insure the hand dredge won't need to be replaced, but instead, rebuilt as needed, flappers the most common item.
The Model 625 when tested using a in/hg vacuum gage achieved and held a -10 in/hg that's more than 1/3 of an atmosphere. It was equipped with 24" of class 200 1 1/2 in. PVC pipe, yielding 55 cubic inches or 30 1/2 fluid ounces.
1 atmosphere (29.92 inches mercury) = 14.695948775 pounds per square inch
1/3 of 14.695948775 = 4.898
1.71 I.D. /2 = .855r
(.855r x .855r) x 3.14159 (pi) = 2.29658
4.898 psi x 2.29658 sq. in. = 11.24866lbs.
If this calculation is right that 11.2487 lbs.would be a lot of weight that could be held to the end of the 1.71 I.D. nozzle. Compare that to the world famous TV vacuum cleaner commercial that used a 16 pound bowling ball to prove their product and that was with a 6" cone so that created a larger area to apply vacuum over, still experts place the water lift of that vacuum at 65", so the model 625 is twice as powerful.
During the pump down phase that dischrges the slurry, the sand, gravel, and gold that was on the way up the hose/pipe looses momentum and might begin to fall back, but a rapid succession of pump strokes will keep it coming virtually walking the larger heavier values up, up and away much like a construction site pump capeable of passing solids. The Model 625 can pump over 25 gallons of water per a minute.
The Model 625 Hand Dredge, works like a typical recreational suction dredge, only the suction is direct, more like a "rocking piston pump" and not dependent upon a weaker power jet venturi that seeks to produce a more constant suction. Best of all, it's ported to easily pass very large 1 1/2" cobbles for when your in a FEVERED hurry, or accepts the large seive nozzle for suctioning and pumping massive amounts of pre-classified overburden material right through to a free flowing sluice or a catchment bucket.
A list of parts and accessories below allows for building a complete hand dredge. Placing a single check mark in any categories box will add that item. Items with negative value can be used to "REBUILD" the above "Basic" dredge.
