Parker Gear Pump : What are the hazards and preventive measures of the gun pump?
1 The vertical stroke of the vertical hydraulic cylinder rises (returns) and produces a strong vibration and a loud sound.
2 The vibration causes the connecting thread to loosen, causing serious oil leakage.
3 Vibration caused the hydraulic components and fittings to rupture and the pressure gauge to be damaged. The system may not be able to continue working, or even cause personal safety and equipment accidents.
The method to prevent the occurrence of the gunming phenomenon is to eliminate the pressure of the gunming phenomenon by first releasing the pressure on the upper chamber of the hydraulic cylinder, that is, the energy is slowly released, and then the pressure is released after the pressure is released (the cylinder is re-boosted to return the stroke) .
1 Use a small solenoid valve to relieve pressure. When the hydraulic cylinder is descending, the small solenoid valve 1 is not energized. When the master cylinder is squeezed, the solenoid valve 2 starts to change forward, and the valve 1 is first turned on for 2 to 3 seconds by means of the time relay; when the pressure of the upper chamber of the hydraulic cylinder drops to a predetermined value or zero, Reversing without pressure causes the hydraulic cylinder to go up, eliminating the "cannon". The unloading valve is used to control the pressure relief. The lower chamber of the master cylinder is an extrusion chamber (working chamber). When 2DT is energized, the pressure oil passes through the three-position four-electrolyte fluid reversing valve 1, the hydraulic control check valve 2, the gear pump enters the lower chamber of the main cylinder for extrusion, and the pressing force rises to the required tonnage, the electric contact pressure gauge 3 Send a letter, 2DT power off, slowly unscrew the special throttle valve 4 by operation, and gradually put the high pressure oil back into the fuel tank; when the pressure value shown in the pressure gauge 5 is reduced to 5 ~ 3MPa, the IDT is energized again, a large number of The low pressure oil flows back to the tank through the valve 2 and the valve 1. 2. The electro-hydraulic reversing valve K core function can be used for pressure relief. Give the signal, IDT is energized, and the pressure oil enters the upper chamber of the master cylinder through the three-position four-electrolyte hydraulic reversing valve 1 to press. When the pressure rises to the predetermined pressure, the electric contact pressure gauge 2 sends a letter, and the time relay is delayed. Pressure. After the pressure is maintained, the IDT is de-energized, and the valve 1 is delayed to the neutral position under the control of the damper with the damper. The high-pressure oil is gradually released through the small to large opening amount as the K-type spool moves. When the spool is moved to the full neutral position, the amount has been largely released. In this way, the "cannon" is greatly reduced. In order to ensure reliable commutation, a back pressure valve should be added at a in the figure.
2. The one-way throttle valve is used to control the pressure relief. After the extrusion signal of the working cycle is sent, the IDT and 2DT are energized, and the pressure oil is introduced into the master cylinder and the quick cylinder through the plug-in poppet valves 1, 2, respectively. After the extrusion is completed, the travel switch sends a letter to energize the 3DT, and the low pressure control pressure oil passes through the two-position three-way electromagnetic reversing valve 3: the one-way throttle valve 4, pushes the small pressure relief valve core of the liquid filling valve 5, and the high pressure The oil is relieved by the damping hole to which the spool belongs; at the same time, the stroke switch also delays the time relay by 1 to 2 s, the oil pressure of the master cylinder has been reduced to a low pressure, the large pressure relief spool has been opened, and the delay is over. 4DT is energized, the pressure oil passes through the valve 1, the one-way sequence valve 6, enters the lower cylinder of the quick cylinder, pushes the extruded beam back to the upper position, and the large amount of oil of the master cylinder is discharged back to the filling tank under the low pressure state to avoid the occurrence of " Cannon."
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