non submersible slurry pump

verificacion de energia en bombas

PUMP SELECTION AND POWER VERIFICATION

Case Study Sample Prepared by Maurice Freivokh DRAGFLOWNORTH AMERICA The client provides information of how many m3 or Tons of solids he needs to move and how much time he has. We need to ask the availa ble wor king hrs/day, days/wee k, weeks per m onth and m onths per year discounting holidays. W ith t he tonnage information and total amount of hours available, we can determine how many Tons we need to move per hour (TPH). The client provides also with: In this case the client needs to move 200 TPH of coarse sand and gravel (with a Specific Gravity of 2.6 tons/m3), in a slurry with approx 50% (C w solids) concentration of solids by weight. With 200TPH of soli ds with a SG of 2.6 tons/m3 w e have 200 / 2.6 = 77 m3/h of solids For pump select ion we need to esti mate the Total Dynamic Head TDH TDH= H + H wet lift + H f Where H is Static Head, H wet lift Head due to submergence and H f is Head due to friction losses. To calculate H wet lift (Head due to submergence) we need to calcul ate the Specific Gravity of the slurry and the Concentration by Volume of the slurry With on Denver Charts we get o r if you have Cv slurry ………. SG slurry = C v solids x S G solids + C v water x S G water SG slurry =0.2778x2.6+0.7222X1=1.444 Now we can calculate the wet lift H wet lift = (SG slurry -S G water ) x S = (1.44 - 1)x15 = 0.44x15 = 6.6m To calculate H f Head due to friction losses., we need to determine the m3/h of slurry and the adequate Pipe Diameter to maintain min 2.0m/sec or 7feet/sec on the line to avoid sedimentation If the concentration by volume of solids is 27.78% then we have 77x100 / 27.78 = 277m3/h of slurry Using the friction losses charts of Cameron Hydraulic Data or the Abaco Flow vs. Pressure, pipe diameter and Line Velocity, for 277m3/h (+/-1,200USGPM) of slurry to avoid sedimentation we need a 8”DIA Pipe resulting on friction losses of f = 2.2% or 2m for each 100m If L = 70m Hf = (70x2.2 /100)x1.7 = 2.62m Then: TDH= H + H wet lift + H f TDH = 25 + 6.6 + 2.62 = 34.22m (Mini mum Head required at the pump) With TDH = 34m and C = 277m3/h we initially select the following pump: EL604 with 100HP To Verify Power: BHP = CxTDHxSG slurry / 270xη Where η is efficiency of pump and motor (Approx 0.5) BHP = (277x34 x1.444) /(270 x 0.5) = 100.73 HP This i s fi ne as the pum p has 100H P plus a SF of 1.3 but a better selection would be the EL604S wit h 120 HP Excavator Power should be 30% more than the Dragflow equipment needs. i.e.: for HY 85 + (2) EXH Y20 we need (85+ 20+20)*1.3=162.5 Hp Then we select a CAT 324 or 325 with 170 Hp H = 25m Static Head or difference in levels between the water surface and the discharge S =15m Submergence, difference in levels between the water surface and the bottom L = 70m total pipe length from pump to pipe discharge use When units are 270 m, HP, m3/H 360 m, kW, m3/H 3900 ft, HP, USG M We should consider a correction factor for slurry of: 1.4 For fi ne sand (C v 25%) 1.7 For coarse sand &gravel (C v 25%) C v slurry = 27.78% S G slurry = 1.444 S G solids = 2.6 C w solids = 50%