Triplex pump

The single-action pump is usually available with three, five and even seven pistons. The odd number of pistons allows the pump to be rotationally balanced, and the use of at least three pistons reduces the discharge pulsation of these single-acting pumps. A three piston pump single-action pump is called a triplex pump. A five piston, or seven piston single-acting pump is called a multiplex pump. 

Mud pumps consume more than 60% of all the horsepower used in rotary drilling. Mud pumps are used to circulate drilling fluid through the mud circulation system while drilling. A pump with two fluid cylinders, as shown in Figure 4-99, is called a duplex pump. A three-fluid-cylinder pump, as shown in Figure 4-100, is called a triplex pump. Duplex pumps are usually double action, and triplex pumps are usually single action. 

The charts showing the p>erformance of duplex pumps are shown in Table 4-38 [17]. The charts showing the performance of triplex pumps are shown in Table 4-39 [17]. A chart listing the pump output required for a given annular velocity is shown in Table 4-40 [18]. A chart listing the power input horsepower required for a given pump working pressure is shown in Table 4-41 [19]. 

Note For single action triplex pump, multiply table value by 0.75. Note Values In the table are calculated tor a pump efficiency of 0.85. Courtesy International Association of Drilling Contractors. 

Theoretical output (gal/min) for a single action triplex pump is... 

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

Determine the appropriate circulation flowrate to be used for the diamond bit, turbine motor combination and the appropriate liner size to be used in the triplex pump. Also, prepare the turbine motor performance graph for the chosen circulation flowrate. Determine the total flow area for the diamond bit. 

An increasing number of plant engineering companies are aware of the importance of life cycle costs and therefore require, together with the pump quotation, an additional cost proposal for a complete pump system. This trend is indicated by an increased demand for Diaphragm Pumps in particular for higher flow rates. Even ten years ago the maximal required flow rate for Triplex Pumps of unit construction has been approximately 50 KW. Today there are units available with nearly ten times the power. 

The rate of fluid discharge from the cylinder is zero at the beginning of a piston stroke and increases to a maximum value when the piston reaches full speed. If only one discharge cylinder is used, the flow rate will pulsate. These pulsations can be reduced by placing an air chamber on the discharge line or by using a number of delivery cylinders compounded. Simplex pumps have only one delivery cylinder, duplex pumps have two cylinders, and triplex pumps have three cylinders. 

Duplex pumps are available (triplex pumps for ORLITA HS4). In these instances, the maximal flow-rate must be multiplied by 2 or 3, respectively. 

In some instances it is possible to connect several heads to the same motor and to obtain duplex or triplex pumps. When each head of a duplex or triplex pump has its own flow adjustment, the pump can feed two or three independent chromatographic systems, Some pumps are equipped with a water-circulating device for cooling the solvent, in order to avoid a temperature increase due to the proximity of the motor and the compression of the liquid (Labotron pumps). 

As seen above, the flow of sinusoidal drive reciprocating pumps is greatly pulsed. Even when a triplex pump is used, a residual pulsation remains (Fig. 9b). Most detectors in general use, especially differential refractoineters, are flow sensitive, the pulses increasing the baseline noise, resulting in a poorer detection limit. Under certain conditions, the pulses can even affect the profile of the eluted peaks and thus the resolution, as the HETP is not a linear function of the actual flow-rate. For these reasons, pulse damping is often necessary. 

TABLE 9-2 Comparison between Duplex and Triplex Pumps ... 

For proper balancing, the pistons of duplex pumps are 180° out of phase (Figure 9-3), but for triplex pumps they are 120° out of phase with each other (Figure 9-4). 

Triplex pumps have a lower degree of oscillation than duplex units. The degree of... 

FIGURE 9-7 Triplex pump TPK 7" x 12"/1600. Driving power 1200 kW (1600 hp). (Courtesy of Wirth Pumps.)... 

Machines that cause one impulse per revolution are punch presses, shears, one-cylinder pumps or compressors, and one-cyhnder engines. Machines that cause a few impulses per revolution are duplex and triplex pumps or compressors, two-, three-, and four-cylinder internal combustion engines, and other reciprocating or cam-actuated machines. The effects of large cyclic loads often can be reduced by putting a fluid couphng or some other type of cushioning device in the drive. 

Figure 9.14 Pulsation reduction (a) simplex pump, (b) pulsation dampener, (c) triplex pump.

This paper introduces the actual performance of the production and surface flow systems and equipment, and points out the influence that the special rheologic characteristics, especially the viscous-elastic nature of the fluid, has on the system and the modification made. For example, there is a normal force acting on the beam pump sucker rods that causes pronounced eccentric mechanical wear on one side of the sucker rods and thereby very short service life for beam-pump wells. This normal force significantly lowers the efficiency of centrifugal pumps, increases the vibration and mechanical degradation in triplex pumps and the whole system, lowers the efficiency of maturing tanks and static mixers, etc. 

The modifications on the system and equipment and their results are shown. For example, the service life of beam pumps more than doubled mechanical degradation of polymer in the system and triplex pumps decreased more than 50 and 70%, respectively and the energy consumption of mixing equipment decreased 80%, among other results. 

Table 1 shows the vibration data at the inlet (suction) and outlet (discharge) side of triplex pumps under different conditions of... 

Problems With Triplex Pumps and Methods To Solve Them... 

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. 

For all these reasons the oxygen content in the water must be kept below 30 ppb. A triplex pump is used to raise the pressure to the injection level with a maximum of 150 bar. 

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