Mechanical principle of PARKER plunger pump in the United States

Mechanical principle of PARKER plunger pump in the United States

The total stroke L of the reciprocating motion of the PARKER plunger pump is constant and determined by the lift of the cam. The fuel supply amount per cycle of the plunger depends on the fuel supply stroke, which is variable and not controlled by the camshaft. The start time of fuel supply does not change with the variation of fuel supply stroke. Rotating the plunger can change the end time of fuel supply, thereby altering the fuel supply amount. When the plunger pump is working, the cam on the camshaft of the fuel injection pump and the plunger spring force the plunger to reciprocate up and down, thereby completing the pumping task. The pumping process can be divided into the following two stages.

Oil inlet process

When the convex part of the cam rotates, under the action of the spring force, the plunger moves downward, and the upper space of the plunger (called the pump oil chamber) generates a vacuum degree. When the upper end face of the plunger opens the oil inlet hole on the plunger sleeve, diesel filled in the oil passage of the upper body of the oil pump enters the pump oil chamber through the oil hole, and the plunger moves to the bottom dead center, and the oil inlet is completed

Return oil process

The PARKER plunger supplies oil upwards. When the inclined groove (stop supply edge) on the plunger is connected to the return hole on the sleeve, the low-pressure oil circuit in the pump chamber communicates with the middle hole, radial hole, and inclined groove on the plunger head. The oil pressure suddenly drops, and the outlet valve quickly closes under the action of the spring force, stopping the oil supply. Afterwards, the plunger will continue to move upwards. When the protruding part of the cam rotates past, under the action of the spring, the plunger will move downwards again. At this point, the next cycle begins. A plunger pump is introduced based on the principle of a plunger. There are two one-way valves on a plunger pump, and the directions are opposite. When the plunger moves in one direction, negative pressure appears in the cylinder. At this time, one one-way valve opens and the liquid is sucked into the cylinder. When the plunger moves in the other direction, the liquid is compressed and the other one-way valve is opened, and the liquid sucked into the cylinder is discharged. This working mode forms continuous fuel supply after continuous movement.

The plunger supplies oil upwards. When the inclined groove (stop supply edge) on the plunger is connected to the return hole on the sleeve, the low-pressure oil circuit in the pump chamber communicates with the middle hole, radial hole, and inclined groove of the plunger head. The oil pressure suddenly drops, and the oil outlet valve quickly closes under the action of the spring force, stopping the oil supply. Afterwards, the plunger will continue to move upwards. When the protruding part of the cam rotates past, under the action of the spring, the plunger will move downwards again. At this point, the next cycle begins. A plunger pump is introduced based on the principle of a plunger. There are two one-way valves on a plunger pump, and the directions are opposite. When the plunger moves in one direction, negative pressure appears in the cylinder. At this time, one one-way valve opens and the liquid is sucked into the cylinder. When the plunger moves in the other direction, the liquid is compressed and the other one-way valve is opened, and the liquid sucked into the cylinder is discharged. This working mode forms continuous fuel supply after continuous movement.

After using the plunger pump with a supplementary oil pump for oil supply for 3000 hours, the operator needs to check the plunger pump 1-2 times a day to check whether the hydraulic pump is operating normally and whether the sound is normal. If it is found that the speed of the hydraulic cylinder has decreased or the car is stuck, the oil replenishment pump should be disassembled and inspected to check whether there are scratches on the impeller edge and whether the clearance between the internal gear pump is too large. For self-priming plunger pumps, the oil in the hydraulic oil tank must not be lower than the lower limit of the oil gauge, and a sufficient amount of hydraulic oil must be maintained. The higher the cleanliness of hydraulic oil, the longer the service life of hydraulic pumps. The most important component of a plunger pump is the bearing. If there is clearance in the bearing, it cannot guarantee the normal clearance of the three pairs of friction pairs inside the hydraulic pump, and it will also damage the thickness of the static hydraulic support oil film of each friction pair, reducing the service life of the plunger pump bearing. According to the information provided by the hydraulic pump manufacturer, the average service life of the bearing is 10000 hours, and if it exceeds this value, a new port needs to be replaced. The clearance of the disassembled bearing cannot be detected without professional testing instruments, and can only be visually inspected. If scratches or discoloration are found on the roller surface, it must be replaced. When replacing bearings, attention should be paid to the English letters and models of the original bearings. Most plunger pump bearings use high load capacity bearings and should be purchased from the original manufacturer with the original specifications. If changing to another brand, experienced personnel should be consulted to check the table for replacement, in order to maintain the accuracy level and load capacity of the bearings. The service life of a plunger pump is related to regular maintenance, the quantity and quality of hydraulic oil, and the cleanliness of the oil. Avoiding particles in the oil from causing wear and tear on the friction pair of the plunger pump is also an effective way to extend the service life of the plunger pump.

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