Gold Prospecting and Placer Mining Hand Powered Suction Dredges

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 M625 HD     M625 HD P

 M2125 2" Gold Hand Dredge Video

 Hand Powered Portable Suction Separator GOLD Dredge 

 US Patent 9,273,677 B2

Model 625 HD series Portable suction separator GOLD dredges, hand powered.

  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. Also, pulling the handle generate's more than double the mechanical force with the water compared to siphoning thereby improving gold recovery.

 A standard in/hg vacuum gauge was used to test the Model 625 HD assembled to be used as each of the available models. In the hands of an adult person of above average strength a constant sealed suction vacuum rating of greater than  minus -10 inches/hg was achieved and held consistently, that's over 1/3 of an atmosphere. For all of the models: standard HD Dredge, Dry Vac, Crevice Dredge, the Bilge dredge and the Aquarium Gravel Vacuum. 

   The per stroke capacity of the Model 625 HD is over 57 cubic inches per stroke.  For the test of the Model 625 HD, as the full size dredge, it was equipped with 24" of class 200 1 1/2 in. PVC pipe. Each 12 inch section of 1 1/2 inch class 200 PVC pipe is around 27 cubic inches or 15 fluid oz., each 12 inch section of 1 1/2 in ABS schedule 40 pipe holds 24 cubic inches. 
   Formulas:

   V = H x PI x (r x r)  volume 

   1 US fluid ounce = 1.8046875 cubic inches.

   1 atmosphere = 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 (area of circle in square inches)

    4.898 psi x 2.29658 sq. in.  =  11.24866 lbs.

 If this calculation is right that 11.25 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. This formula would suggest that the golden sniffer equipped with a 6 inch cone would be able to hold a 39.5 lb. bowling ball. Of course, the larger the volume of space that the vacuum is being created in, the shorter the duration of the vacuum effect once suctioning dredge material begins. So  apply this formula when trying to determine how fast you need to work any hand pump: 1 US fluid ounce = 1.8046875 cubic inches.