Synthesis and analysis of the hottest double beam

2022-08-02
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Synthesis and analysis of double beam pumping unit with extended range and force balance

improving the stroke of rod pumping unit will undoubtedly bring many benefits. However, increasing the stroke of sucker rod by directly increasing the beam will make the beam pumping unit too large. In addition, in the conventional beam pumping unit, the balance weight connected to one end of the crank is used to reduce the driving force of the crank. When the stroke increases, the counterweight mass must also be increased, which not only increases the horizontal dynamic load of the pumping unit system, but also increases the size and complexity of the crank rocker mechanism, which is not conducive to the smooth operation of the pumping unit system. Therefore, how to improve the conventional beam pumping unit to improve its stroke and reduce the driving force and the overall volume has always been the research goal of oil production researchers. Considering the above factors, actual working conditions and manufacturing costs, the author adopts the plane connecting rod system on the basis of the conventional crank rocker mechanism which directly touches the sensor joint beam at the controller end by hand. Therefore, the environmental experimental equipment must have the characteristics of safe operation, convenient operation, reliable use and long service life. The following two mechanisms integrating the functions of range extension, mechanical reversing and driving force balance are constructed by the comprehensive method of plane connecting rod system, To improve the stroke of the pumping unit and reduce the driving torque of the crank, the force analysis and stroke calculation are made for each scheme, and the calculation formulas of the stroke, counterweight mass and driving force of the pumping unit are derived. Finally, the various schemes are compared and analyzed. 1. The reverse synthesis method is adopted for the synthesis of scheme 1 of the extended range and driving force balance mechanism. From the feasible planar linkage system with a degree of freedom of 1, a 10 bar planar linkage system (2 quaternion bars, 2 ternary bars, 6 binary bars and 13 single hinge points) is used, as shown in Fig. 1a, to construct the extended range and power balance mechanism scheme 1 of the double beam pumping unit, as shown in Fig. 1b and C. In this 10 bar planar connecting rod system, three-dimensional rods 1 and 2 are used to replace the frame and crank respectively, four-dimensional rods 4 and 6 are used to replace the upstream and downstream beams respectively, two-dimensional rods 3, 5 and 7 are used to measure the tensile strength of paper, paperboard and other similar thin sheet materials, and 8, 9 and 10 are used to replace the upper connecting rod, lower connecting rod, traction belt, guide wheel, balance belt and balance wheel respectively. In order to concisely express the motion function of the planar linkage system, only the above-mentioned main motion elements reflecting the motion characteristics in the mechanism are considered, without considering the balance weight of the secondary motion elements, the sucker rod and the auxiliary balance weight, and two curvilinear arrows are used to represent the input and output ends of the motion respectively. Fig. 1 Schematic diagram of planar connecting rod system (a) and double beam pumping unit (B, c) of scheme 1 the principle and characteristics of the range increasing and driving force balancing mechanism of scheme 1 are described as follows: scheme 1 is a combination of the upper and lower crank rocker mechanisms, the left balance weight pulley force increasing mechanism and the right pulley range increasing mechanism of the conventional beam pumping unit. The upper crank rocker mechanism is a four-bar mechanism composed of frame 1, crank 2, connecting rod 3 and upstream beam 4 to realize the swing of the upstream beam. The lower crank rocker mechanism is a four-bar mechanism composed of a frame 1, a crank 2, a lower connecting rod 5 and a downstream beam 6 to realize the reverse swing of the downstream beam relative to the upstream beam. The left balance weight pulley force increasing mechanism is composed of balance weight, balance wheel, upstream and downstream beams, balance belt and base. The balance wheel is hinged with the left end of the upstream beam, and both ends of the balance belt are respectively connected with the left end of the downstream beam and the balance weight and bypass the balance wheel

when the upper and lower beams swing, the balance weight moves up and down with the balance wheel, and with the help of the balance wheel and the balance belt, the two times and one time of the mass force of the balance weight are added to the left end of the upstream beam and the left end of the downstream beam respectively, so that the crank driving torque of the upper and lower strokes reaches the uniform load, and is far less than the crank driving torque before balancing. The right belt wheel range extension mechanism is composed of a traction belt, a guide wheel, upstream and downstream beams and a base. The guide wheel is hinged with the right end of the upstream beam, and both ends of the traction belt are respectively connected with the right end of the downstream beam and the sucker rod and bypass the guide wheel. When the upstream and downstream beams swing reversely, the sucker rod moves up and down with the guide wheel. The stroke of the sucker rod is increased by three times by the guide wheel stroke doubling function and the upstream and downstream beam reverse swing extension function. The characteristics of the pumping unit system are that it uses the mechanical reversing function of the crank rocker mechanism, the force increasing balance function of the balance weight pulley force increasing mechanism and the range increasing function of the pulley range increasing mechanism to realize stable mechanical reversing, and uses a small driving force to obtain a larger stroke. In scheme 1, two double outlet output shafts of the reducers arranged in parallel can be fixedly connected with two cranks, and one motor drives the input shafts of the two reducers to rotate synchronously through belt drive, making the structure simple and compact, as shown in Figure 1C. 2 Calculation of driving force parameters and range increase coefficient 2.1 relationship between connecting rod driving force and working load

when the upstream beam of the pumping unit swings counterclockwise and clockwise around the hinge point of the tower, the sucker rod makes up stroke motion and down stroke motion respectively. The stress condition of the system is shown in Figure 1b. According to the force balance condition, fu1a=wu (1+1/η) b-m1(g-a0)(1+ η) c,

Fu2a=Wu(b/η)- m1(g-a0)c. η,

Fd1a=m1(g+a0)(1+1/η) c-Wd(1+ η) Applicable to ul1005b,

fd2a=m1 (g+a0) (c/η)- Wdb. η。 (1) Where, fu1 and FD1 are the driving force in the vertical direction between the upstream beam and the upper connecting rod in scheme 1 during the up stroke and down stroke of the sucker rod respectively; Fu2 and fd2 are the driving force in the vertical direction between the downstream beam and the lower connecting rod in scheme 1 during the up stroke and down stroke of the sucker rod respectively; Wu and WD are the working loads of the polished rod on the upstroke and downstroke of the sucker rod respectively; M1 is the balance weight mass in scheme 1; A is the distance from the hinge point of connecting rod and traveling beam to the hinge point of tower; B is the distance from the center of the guide wheel to the hinge point of the tower; C is the distance from the center of balance wheel to the hinge point of tower; G is the acceleration of gravity; A0 is the motion acceleration of the counterweight; η Is the efficiency of the guide and balance wheels, η= 0.97。 2.2 counterweight mass, rising stroke and driving force of sucker rod

in order to reduce the crank driving torque, it shall be ensured that when the traveling beam is placed to the horizontal position, the crank driving torque during the up stroke and down stroke of the sucker rod is equal and in the same direction, that is, the balance condition shall be met: fu1+fu2=fd1+fd2. Thus, the formula for calculating the reasonable mass M1 of the balance weight in scheme 1 can be obtained: (2)

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