Pumps volumetric efficiency

Calculate the optimal hydraulic parameters for the hole depth of 8,555 ft if the available data are as given below Type of pump Continental Emsco F-1600 with 97% pump volumetric efficiency. To prevent rapid pump wear, the pump pressure should not exceed about 80% of the maximum pump pressure at any liner size. The hole size is 12- - in. and the mud weight is 9.7 Ib/gal. 

Figure 7 shows the system net useful nitrogen flow and the turbine flow versus system pressure for 80 F and 500 F and for 70 per cent, 80 per cent, and 90 per cent pump volumetric efficiency. Present performance gives only 70 per... 

There are three main problems with triplex pumps designed to pump Newtonian fluids and that are also used for pumping fluids with elastic properties. First, there is serious vibration second, there is low pump volumetric efficiency (approximately 80 to 85% for PAM fluid, while for water it was higher than 95%) third, there is serious shear degradation (about 15%) to the PAM fluid. 

Ev = volumetric efficiency, ratio of actual pump capacity to the volume displaced/imit time... 

The slip of a pump is fraction or percent loss of capacity relative to theoretical. Slip is (1 — Cvoi), w here e oi is the volumetric efficiency. Volumetric efficiency is the actual liquid pumped (usually considered water) relative to that which should theoretically be pumped based on piston displacement. 

Volumetric efficiency, ratio of actual pump capacity to volume displaced per unit of time Pump efficiency with water, percent Pump efficiency with viscous fluid, percent Pump efficiency, fraction Pump efficiency with water, fraction Pump efficiency with viscous fluid, fraction Volumetric efficiency, fraction Maximum safe flowng efficiency, overall pump, fraction... 

These pumps require the maintenance of very close clearances between rubbing surfaces for continual volumetric efficiency. Some of the important pumps are discussed. 

Pump Discharge Voiume (Gai./Stroke) (Based on 100% Volumetric Efficiency)... 

The volumetric efficiency Ti for duplex pumps or triplex pumps is... 

The volumetric efficiency factor is about 0.95 for precharged pumps. 

Pump Limitations. Table 4-116 shows there are six possible liner sizes that can be used on the Model E-700 mud pump. Each liner size must be considered to obtain the optimum circulation flowrate and appropriate liner size. The maximum pressure available for each liner size will be reduced by a safety factor of 0.90. The maximum volumetric flowrate available for each liner size will also be reduced by a volumetric efficiency factor of 0.80 and an additional safety factor of 0.90. Thus, from Table 4-116, the allowable maximum pressures and allowable maximum volumetric flowrates will be those shown in Figures 4-207 through 4-212, which are the liner sizes 5j-, 6, 6-[, 6- and 7 in., respectively. Plotted on each of these figures are the total pressure losses for the various circulation flowrates considered. The horizontal straight line on each figure is... 

Figure 32.27 shows how a centrifugal pump is affected, particularly at low flow rates, and the behavior is typical of conventional centrifugal pumps. Figures 32.28 and 32.29 present well-known information on the effects of dissolved and entrained gas on the volumetric efficiency of a positive displacement pump. 

In theory, a pump delivers an amount of fluid equal to its displacement each cycle or revolution. In reality, the actual output is reduced because of internal leakage or slippage. As pressure increases, the leakage from the outlet to the inlet or to the drain also increases and the volumetric efficiency decreases. 

For example, if a pump theoretically should deliver 10 gpm by delivers only 9 gpm at 1000 psig, its volumetric efficiency at that pressure is 90 per cent. 

The main effects of a higher condensing temperature will be a drop in the refrigerating effect, since the liquid enters the expansion valve hotter, and a decrease in volume pumped due to the lower volumetric efficiency. There will also be an increase in the drive motor power. 

The theoretical delivery of a piston pump is equal to the total swept volume of the cylinders. The actual delivery may be less than the theoretical value because of leakage past the piston and the valves or because of inertia of the valves. In some cases, however, the actual discharge is greater than theoretical value because the momentum of the liquid in the delivery line and sluggishness in the operation of the delivery valve may result in continued delivery during a portion of the suction stroke. The volumetric efficiency, which is defined as the ratio of the actual discharge to the swept volume, is normally greater than 90 per cent. 

Another efficiency which is important for positive displacement pumps is the volumetric efficiency. This is the delivered capacity per cycle as a percentage of the true displacement per cycle. If no slip occurs, the volumetric efficiency of the pump is 100 per cent. For zero pressure difference across the pump, there is no slip and the delivered capacity is the true displacement. The volumetric efficiency of a pump is reduced by the presence of entrained air or gas in the pumped liquid. It is important to know the volumetric efficiency of a positive displacement pump when it is to be used for metering. 

Equation (2.16) implies that the compression k attainable with a Roots pump must always be less than the grading k, between Roots pump and backing pump since volumetric efficiency is always < 1. When combining equations (2.13) and (2.16) one obtains for the efficiency the well known expression... 

Brake, hydraulic, and recoil-cylinder fluids fall in much the same field of operating conditions. These are employed in systems in which operating units are exposed to low temperatures, and in practically all cases the connecting tubing lines are so exposed. Temperatures are not likely to go very high, but for aviation, temperatures as low as —70° F. may be frequent. Practically all brake systems and many hydraulic systems employ reciprocating units packed with synthetic rubbers. Hydraulic systems employ rotary pumps and often rotary motors these cannot be soft packed but are only capillary-sealed—i.e., close clearances. These pumps and motors drop in volumetric efficiency as viscosity falls. 

The fluid must not fall below a definite viscosity at, say, 160° F. so that the rotary pump and motor volumetric efficiency keeps above a minimum value to operate the system satisfactorily. 

A. Ishibashi, Studies of Volumetric Efficiency and Theoretical Delivery of Gear Pumps, Bull. Jp. Soc. Mech. Eng., 13, 688-696 (1970). 

The volumetric efficiency of the Roots pump is thus determined, leading to Seff. As ... 

The lower the volumetric efficiency and the higher the number of plungers, the lower the pulsation of the pump. 

Figure 1 shows a triplex plunger pump and its flow pulsation at a volumetric efficiency of 95 %. The volumetric efficiency, representing the ratio of the actual volume flow Q to the theoretical flow (equation (1)), depends essentially on the fluid and working chamber elasticity... 

The theoretical fluid displacement of a piston pump equals the total volume swept by the piston on each delivery stroke. Because of leakage past the piston and the valves and failure of the valves to close instantly, this theoretical displacement is not attained in actual practice. The volumetric efficiency, defined as the ratio of the actual displacement to the theoretical displacement, is usually in the range of 70 to 95 percent. 

Air saturation systems—The advance in dissolving air into water has come primarily from injecting air into pumps capable of handling water with entrained air. The operating pnmps work at higher pressure than standard centrifugal pumps, which increases both air satnra-tion and volumetric efficiency. 

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