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Do you have these common complaints about pumps for crude, resid, petrochemicals, refined petroleum products, viscous and non-Newtonian fluids? 1) There's no way to change capacity. 2) Efficiency could be better. 3) They run so hot that you have to cool them. 4) When you want them to run really hot, there's no easy way to heat them. 5) You're in trouble when they lose their prime. 6) Noise and maintenance are real problems. Now there is a way to change capacity GTS (geared twin screw) pumps from De Laval have many features which cor- rect or bypass these difficulties. Take capacity, for example. The plot at right shows flow rate vs. speed for the five casing sizes available. What is impor- tant is that within each casing size, there are 4-6 capacities available. casing size nominal capacity (USgpm*) 133 100-950 208 400-290 268 1300-4500 320 2500-5800 400 3400-9000 *A P=O Capacities can be changed just by changing screw sets (since the capac- ity of a screw pump depends on the lead of the screws). GTS pumps also give you the opportunity of specifying reversibility with full rated flow in either direction. And you can get increased efficiency Several design and manufacturing fea- tures increase economy of operation of GTS pumps. First, the thread profile is a double epicycloid which minimizes internal slip. This adds efficiency points to any calculation. Second, since the profile is symmetrical, tighter machining tolerances are possible. This increases suction capability and adds to the over- all integrity of design. And finally, tim- ing gears are alloy steels, hardened and ground to reduce friction losses still more. All this adds up to fewer kilowatt hours used over the year. Temperature control is possible too Other design features make GTS pumps easy to keep cool or hot, as you desire. These are oversized bearings, the high efficiency timing gears and an extra- large oil reservoir which dissipates heat without the added expense of an exter- nal lube cooling system. But if you do want your pump to run hot to maintain fluidity, an integral heat chamber cast into the case can be readily adapted for either steam or hot oil. Complete steam jackets are also available for operating temperatures up to 600° F. You don't have to lose your prime Unlike conventional two-screw pumps, De Laval GTS pumps do not drain com- pletely even if suction lines are evacu- ated. Fluid retained in the pump keeps screws wetted and lets full suction develop at all times. (For product change-over, there is a plug which per- mits complete draining.) If the pump is run dry as in stripping tanks, retained fluid cools and lubri- cates the seals and packing, prevent- ing damage to shaft or seals. No dam- age to the screws occurs either, since there is no metal-to-metal contact be- tween the pumping elements. This last feature lets GTS pumps handle water and fluids of low lubricity and high vapor pressure. There's no need to shout when this pump is running The lack of direct screw contact and the unique profile of the screws which s ^ 1000 O •D w 500 O < % 200 O 100 / r /T < V* \u> \ -o 200 SOO 1U0U SPEED (RPM) minimizes fluid shear do a lot to reduce noise. GTS pumps operate below 85 dB(A). This has significance not just for OSHA compliance but also for keeping your neighbors friendly. There's no need to shout at it either Maintenance of GTS pumps is really low. If you're skeptical, ask our other customers. Shaft end angular contact ball bearings are grease-lubricated, timing gears and heavy duty roller bear- ings are oil bath-lubricated. All bear- ings and gears are external to the fluid being pumped. Mechanical seals are standard and if you need them, you can get tungsten carbide facings for abra- sive duty. (Double mechanical seals and stuffing boxes are also available.) Summing things up, if you need a pump to handle viscosities up to 4,500,000 SSU at discharge pressures up to 300 psig, capable of tolerating suction pressures up to 100 psia and suction lifts up to 26" Hg — a pump that comes in horizontal, vertical and deep well configuration, that's effi- cient, versatile and not overly de- manding of maintenance, that offers the reliability of IMO® three-screw pumps — it will pay you to find out more about the line of De Laval GTS pumps. For information, write IMO Pump Division, De Laval Turbine Inc., POB 321, Trenton, NJ 08602, or call 609: 587-5000. mechanical seals DEL306A built-in adjustable relief valve changeable screws hardened and ground gears May 15, 1977 11
