As shown in the figure, when the plunger rod reaches the leftmost position and the hydraulically controlled reversing valve is switched to the right position, the plunger can be moved to the right to work the left suction valve and the right discharge valve. Through the hydraulic control oil line, pressure oil can be applied to both ends of the pilot-operated reversing valve to achieve the change of the hydraulically controlled reversing valve to the right position. Since the right end of the pilot valve is larger than the left end, the spool of the pilot valve moves to the left.
If the plunger rod reaches the rightmost end, the hydraulically controlled reversing valve is shifted to the left position (through the pilot-operated oil circuit so that the right end is connected to the left end of the oil return port and is still the pressure oil) so that the plunger rod moves to the left and the left-row slurry valve is And the left suction pump work.
2.2 The working principle of the pneumatic reciprocating pump The working principle of the pneumatic reciprocating pump As shown in the figure, the position shown in the figure is when the piston reaches the rightmost end, the claw on the piston rod toggles the reversing mechanism consisting of a shift lever, a frame and a push rod. The action makes the right position of the stroke valve conduct, and the control gas path acts on the reversing valve to change its valve position so as to realize the leftward commutation motion of the piston, so that the right suction valve and the left platoon valve work; similarly, The rightward commutation movement of the piston is achieved, so that the left suction valve and the right discharge valve work.
At present, the reversing mechanism used in our country can be divided into three categories according to its structural characteristics: (1) hydraulic control or gas control reversing mechanism, such as the hydraulic control reversing mechanism; (2) motor-air control (or hydraulic control ) Reversing mechanism, such as the maneuver-pneumatic control reversing mechanism composed of a lever, a stroke valve and a reversing valve; 3) a maneuvering-electronically controlled reversing mechanism characterized by: when the piston arrives At the end of the stroke, the collision block that is linked with the piston rod collides with the mechanical contact, and the reversing valve is reversed by the electronic control system, thereby reversing the movement of the piston rod. The downhole electrical equipment must be riot proofed, bulky and costly, and should be used as little as possible.
3.1 Hydraulically controlled reciprocating pump Hydraulically controlled automatic reversing mechanism Hydraulically controlled reciprocating pump Hydraulically controlled automatic reversing mechanism For example, hydraulic cylinders have nine interfaces a, b, c, d, e, f, g, A, B, A The two ports B and B are the main ports, and a, b, c, d, e, f, and g are the control ports; the plunger rod and the hydraulic cylinder form two rings of S and Q to make the control circuit open; There are eight interfaces for h, i, j, k, C, D, O, and P on the valve cylinder body, where P is the oil inlet, O is the oil return port, and C and D are the hydraulic cylinder and the reversing valve. Connect the oil port, connect with A and B respectively, h, i, j, and k are the control. Connect the control port according to the figure c. The piston position on the piston rod reaches the leftmost end and the reversing valve spool. The two extreme positions of the right position are reached, that is, the rightward commutation motion of the piston is achieved through the leftward commutation movement of the directional valve spool. Because the right side of the valve core area is greater than the left side of the role of the area, as long as the spool and left and right ends are connected to the pressure port can make the spool to the left movement, can be achieved by the following process: pressure oil from the left end of P into the valve, role At the left end of the valve core; at the same time, the pressure oil reaches the right end of the valve core via i*a*S*crh*n, so that the valve core moves to the left. When the spool moves to the left and oil port h is blocked, the pressure oil acting on the right end of the spool is replaced by i*a*S*b*j, allowing the spool to continue to the left until it moves to the left. The spool is in the left position, the pressure oil is from P*m*C*A to the left piston chamber, and the piston in the right chamber is the pressure oil from B*D*O to the fuel tank, and the piston moves to the right. When the piston moves to the right and oil port b is blocked, the pressure oil acting on the right end of the valve plug is supplemented by g*j, maintaining the valve plug in the left position until the piston reaches the right end.
When the piston moves to the rightmost end, the annular groove Q communicates the three oil ports d, e, f. At this time, the oil port d communicates with the oil return port O via the oil port k, so it communicates with the oil ports f, e. The oil ports j and h are also connected to the oil port O, that is, the right end of the valve plug is connected to the oil return port O, and the valve plug moves to the right under the pressure oil at the left end until it moves to the right end. The spool is in the right position, the pressure oil is from the port P*l*D*B to the right chamber of the piston, and the low pressure oil in the left chamber of the piston is moved from the port A*C*O to the tank to move the piston to the left. Since the right end of the valve plug is always connected with the oil return port in this process, the valve plug is always in the right position, so that the piston can continue to move leftward until it reaches the leftmost position.
In this way, the reversing movement of the spool of the reversing valve is restarted by the hydraulically controlled oil passage, and automatic reciprocating movement of the plunger rod is realized.
3.2 The pneumatic reversing pump's motor reversing mechanism (a) is the reversing mechanism of the ordinary injection pump. Practice shows that it can basically meet the reversing requirements. However, it is found that it wears in use and it is easy to fail, and the push rod does not move. smooth. In order to find out the reason, through the analysis of the force situation, obtain PRi, R2Ri = (Q * putter load Ri, R2 * total reaction force acting on the push rod on both sides of the rail> 92 friction angle, pressure The angles P, Ri, and R2 all cause frictional wear of the moving pair, making the movement of the putter inflexible, that is, the reason for the failure of the reversing mechanism, and thus the optimum force condition is (a+9i)=0. The lever is made into a curved surface, and the push rod is made into a plane and converted into a (b) reversing mechanism, ie, a flat-bottom moving push rod disc cam mechanism. If the contact of the high-pair contact is ignored, that is, 9=0, although a=0 can be satisfied. The conditions, but for many cam profile curves, there is a force arm between the high contact point and the guide rail, there are also P, Ri, R2: therefore it is necessary to find the profile curve that makes L constant equal to zero.Because the centering cam only has the contour curve L = 0 can be satisfied for the circle, and it can not achieve the displacement of the push rod, so it should be studied from the offset cam mechanism, the involute gear rack mechanism in the meshing drive, the direction of force is always the same and along the meshing In the normal direction of the point, when the pressure angle is zero degrees, the direction of the rack movement and The force profile curve is designed to be involute, the pusher is flat, and the offset eccentricity is the involute base circle radius r/* which satisfies a and L constants of zero, and P=Q, Ri=R2=0 The push rod is best subjected to force. If the shift lever is rotated at equal angular speed, the push rod moves at the same speed as the speed, so the push rod moves smoothly.
4 Conclusion In the hydraulic control reversing mechanism, the oil pressure at both ends of the spool of the reversing valve is accurately changed by controlling the oil passage. If the oil pressure at both ends of the spool is equal, it will change its direction of movement by the difference in area between its two ends; if the oil pressure at the two ends of the spool is not equal, it will change its direction of movement by the pressure difference between its two ends. As a result, the reciprocating motion of the valve core is resumed, and an automatic reciprocating motion of the plunger is achieved. As a component of the BYZ-i20/i0 hydraulic reciprocating piston pump, the commutation frequency is 44 times/min. The pump has been built underground in the Xinwen Mine of Xinwen Mining Bureau, and it is in the Zaozhuang Mining Bureau. Huangbei mine was grouted and water plugged.
In the motor reversing mechanism, a zero-degree pressure angle involute cam mechanism is used as the reversing mechanism f21, and the cam acts as a motive element to make the push rod reversibly move. During the reversing motion, the pressure angle is always zero and the push rod is only By the thrust in the direction of movement, if the cam rotates at equal angular speed and the push rod moves at the same speed, the change of direction is smooth. As a component of the BYH-50/5 type pneumatic reciprocating piston pump, the frequency of commutation is 74 times/min. The pump has been built downhole in the Tangjiazhuang Mine of the Kailuan Mining Bureau. The use of these two reversing mechanisms indicates that the two reversing mechanisms have stable commutation, reliable operation, and long service life, especially when applied under explosion-proof conditions in the mine, and have obvious advantages (according to the search, there are no such two kinds at home and abroad. Reversing mechanism).
With a lower heat load (65% capacity of the design capacity), the heat exchanger can meet the heat transfer requirements while ensuring sufficient circulating cooling water flow.
In the case of high heat load (100% capacity of design capacity), the light pipe heat exchanger can guarantee the heat exchange requirements while ensuring high circulating cooling water flow of 150,000 kg/h, but it is difficult to guarantee such high cooling water under normal circumstances. flow.
The bellows heat exchanger can meet the high heat load working requirements in the case of general cooling water flow, but the pressure drop over the shell side is too large. In order to increase the flow rate of the cooling water in the tube side, the shell pressure is reduced and the sufficient heat exchange area can be ensured. The total number of tube bundles is reduced by 10% and the heat transfer effect is better.
The best working parameter of the bellows heat exchanger is the high heat load; the cooling water flow is 100000kg/h; the inlet and outlet temperature of the cooling water is 33~42. According to the calculation result, if the number of tubes of the bellows heat exchanger is still changed by the original light pipe With 1192 heat exchangers, the heat exchanger tube flow rate is low, the shell pressure drop is too high. In order to increase the water flow rate of the tube and reduce the pressure drop of the shell, the number of tubes of the bellows heat exchanger was reduced from 1192 to 1076, a reduction of 10%. The temperature of the inlet and outlet of the circulating water was controlled at 33~42*C. The pressure drop of the shell process can be reduced from 152.8 kPa to 137.3 kPa. The water flow rate is increased from 0. 299 m/s to 0.331 m/s. The heat transfer effect is expected to be significantly improved to meet the requirements of the device production process. Obviously, this will not only use the original equipment, but also save on the cost of renovation.
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