A plunger pump with a booster impeller capable of reducing inlet pressure pulsation

Abstract

This invention discloses a plunger pump with a booster impeller that reduces inlet pressure pulsation. The booster impeller is located at the inlet of the plunger pump and is mounted on the plunger pump's shaft, rotating coaxially with the plunger. The outlet of the booster impeller is connected to the oil inlet of the plunger via a volute and a connecting pipe. The number of blades on the booster impeller is equal to the number of plungers in the plunger pump. The assembly relationship between the booster impeller and the plungers satisfies the following condition: when any plunger is in a dead position, the outlet of one blade of the booster impeller is in the position of the tongue of the volute. This invention can increase the inlet pressure while reducing the pressure pulsation caused by the introduction of the booster impeller, without adding new components. The plunger pump has a simple and compact structure.

Description

Technical Field

[0001] This invention relates to the field of plunger pumps, and more specifically to a plunger pump with a booster impeller that can reduce inlet pressure pulsation. Background Technology

[0002] Piston pumps are widely used in hydraulic systems due to their high pressure and high flow rate. Piston pumps often experience cavitation due to insufficient inlet suction pressure. When air bubbles flow through high-pressure areas, they collapse due to the surge in pressure, damaging the structural surfaces and ultimately shortening the pump's lifespan. Therefore, to ensure the internal oil pressure is higher than the saturation pressure where cavitation occurs, the inlet pressure of the axial piston pump should be higher; this inlet pressure is the critical inlet pressure. To increase the inlet pressure, existing technology proposes adding a booster turbine at the inlet to ensure the suction oil pressure is higher than the critical pressure. However, the introduction of the booster turbine itself generates pressure pulsations during rotation, and the piston pump also generates pressure pulsations during periodic suction. The coupling of these two pressure pulsations can increase the inlet oil pressure pulsation, worsening inlet conditions and introducing instability into pump operation. This pulsation not only affects pump performance but also causes vibration, noise, and premature wear of system components. Existing technologies often employ physical vibration damping devices or the addition of accumulators to mitigate pulsation, but these methods are typically bulky, costly, and have limited effectiveness. Therefore, there is an urgent need for a simple and efficient low-pulsation design method to address the problem of pressure pulsation at the plunger pump inlet. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a plunger pump with a booster impeller that can reduce inlet pressure pulsation. This not only increases the inlet pressure of the plunger pump but also reduces the pressure pulsation caused by the introduction of the booster impeller.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A plunger pump with a booster impeller that can reduce inlet pressure pulsation, wherein the booster impeller is disposed at the inlet of the plunger pump and is mounted on the shaft of the plunger pump, rotating coaxially with the plunger of the plunger pump.

[0006] The outlet of the booster impeller is connected to the oil inlet of the plunger of the plunger pump through a volute and a connecting pipe.

[0007] The number of blades in the booster impeller is equal to the number of plungers in the plunger pump.

[0008] The assembly relationship between the booster impeller and the plunger satisfies:

[0009] When any plunger is in the dead position, the outlet of one of the blades of the booster impeller is in the tongue position of the volute.

[0010] Furthermore, the booster impeller is a centrifugal turbocharger impeller.

[0011] Furthermore, the booster pressure value p of the booster impeller is calculated using the following formula:

[0012] p = (1.1 ~ 1.3)(p k -p min )

[0013] Where, p min and p k The minimum pressure and critical pressure at which the plunger pump operates without a booster impeller are defined as the pressure at which cavitation does not occur.

[0014] Furthermore, the connecting pipe between the volute and the oil inlet of the plunger of the plunger pump is a streamlined connecting pipe.

[0015] The beneficial effects of this invention are as follows:

[0016] The present invention provides a plunger pump with a booster impeller that can reduce inlet pressure pulsation. By utilizing the controllability of the pulsation waveform generated by the booster impeller and the controllability of the pressure pulsation waveform generated by the plunger pump, the pressure pulsation at the plunger pump inlet is reduced. At the same time, by utilizing the controllability of the pressure pulsation waveform generated by the turbine and the pressure pulsation waveform generated by the plunger pump, the phase difference between the two pulsation waveforms is reasonably set by limiting the number of blades of the booster impeller and the installation position of the booster impeller and the plunger, the pressure pulsation is weakened by waveform superposition. No new parts are required. The plunger pump has a simple and compact structure and is easy to manufacture and install. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a plunger pump with a booster impeller that can reduce inlet pressure pulsation according to an embodiment of the present invention.

[0018] Figure 2 for Figure 1 AA sectional view and enlarged partial view.

[0019] Figure 3 for Figure 1 BB cross-sectional view.

[0020] Figure 4 The waveform diagram shows the pressure pulsation generated at the outlet of the booster impeller and the pressure pulsation generated at the inlet of the plunger pump.

[0021] In the diagram, 1 is the booster impeller, 2 is the connecting pipe, 3 is the plunger pump inlet, 4 is the plunger pump outlet, 5 is the shaft, 6 is the plunger pump cylinder, 7 is the plunger, 8 is the slipper, and 9 is the swashplate. Detailed Implementation

[0022] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become clearer. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0023] like Figure 1 As shown, the plunger pump with a booster impeller in this embodiment, which can reduce inlet pressure pulsation, includes a booster impeller 1, a connecting pipe 2, a plunger inlet 3, a plunger outlet 4, a rotating shaft 5, a plunger pump cylinder 6, a plunger 7, a slipper 8, and a swashplate 9.

[0024] A booster impeller 1 is located at the inlet of the plunger pump and is splined onto the plunger pump shaft 5. The outlet of the booster impeller 1 is connected to the oil inlet of the plunger 7 via a volute and connecting pipe 2, thereby delivering the oil pressurized by the booster impeller 1 into the plunger 7. The shaft 5 is also splined to the plunger pump cylinder 6, and the shaft 5 drives the plunger pump cylinder 6 and the booster impeller 1 to rotate synchronously. The number of blades in the booster impeller 1 is equal to the number of plungers 7 in the plunger pump.

[0025] like Figure 2 and Figure 3 As shown, the assembly relationship between the booster impeller 1 and the plunger 7 satisfies:

[0026] When any plunger is in the dead position, the outlet of one of the blades of the booster impeller 1 is in the tongue position of the volute.

[0027] In this embodiment, the booster impeller 1 is a centrifugal turbo booster impeller, with 9 plungers 7 and 9 blades.

[0028] Connecting pipe 2 is a streamlined connecting pipe with a streamlined flow channel.

[0029] When there is no booster impeller 1, the pressure pulsation waveform at the plunger pump inlet is as follows: Figure 4 As shown by the solid line, when the plunger reaches the top dead center position, it switches from a pressure state to a suction state. Due to oil inertia, the oil at the plunger pump inlet cannot yet meet the suddenly increased suction demand. The waveform shows that the pressure at the plunger pump inlet is at its lowest at this point, and the pressure only recovers as the plunger chamber continues to rotate. Without considering the plunger pump, the outlet pressure pulsation waveform of the booster impeller is as follows: Figure 4As shown by the dashed line, when the impeller blades sweep across the volute tongue, they compress the oil, resulting in the highest pressure. Since pressure propagates in oil at the speed of sound, and the length of the oil outlet pipe connecting the booster impeller is much shorter than the speed of sound, it can be assumed that when the plunger pump is equipped with the booster impeller, the two pressure waves received by the plunger pump inlet channel arrive almost simultaneously. Pressure waves are mechanical waves, and their superposition is possible. In this embodiment, during the assembly of the plunger pump and the booster impeller, any plunger 7 is installed at the dead center position, and any blade of the booster impeller 1 is installed at the volute tongue position. This ensures that when any plunger is at the dead center position, the outlet of one blade of the booster impeller 1 is at the volute tongue position. At this time, the pressure pulsation wave generated by the booster impeller 1 and the pressure pulsation wave generated by the plunger pump are exactly half a cycle out of phase, meaning that the booster impeller generates the highest pressure when the plunger pump generates the lowest pressure. The superposition of the two waves suppresses most of the peak fluctuations. This achieves the goal of reducing pressure pulsation at the plunger pump inlet.

[0030] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A plunger pump with a booster impeller capable of reducing inlet pressure pulsation, characterized by, The booster impeller (1) is located at the inlet of the plunger pump. The booster impeller (1) is mounted on the shaft (5) of the plunger pump and rotates coaxially with the plunger (7) of the plunger pump. The outlet of the booster impeller (1) is connected to the oil inlet of the plunger (7) of the plunger pump through the volute and connecting pipe. The number of blades of the booster impeller (1) is equal to the number of plungers (7) of the plunger pump; The assembly relationship between the booster impeller (1) and the plunger (7) satisfies: When any plunger is in the dead position, the outlet of one of the blades of the booster impeller (1) is in the tongue position of the volute. The booster impeller (1) is a centrifugal turbo booster impeller; The booster pressure value p of the booster impeller is calculated by the following formula: p =(1.1~1.3)( p k - p min ) wherein p min and p k Pcrit is the critical pressure at which the pump operates without cavitation and without the plunger pump operating with the booster impeller. The connecting pipe that connects the volute and the oil inlet of the plunger (7) of the plunger pump is a streamlined connecting pipe.

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