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How to deal with the vibration and noise of the melt gear pump?

1. The very high level of vibration of the melt gear pump is caused by the inhalation of gas in the gear pump.

When the gear pump is in operation, the vibration and noise are very much related to the entry of the steam into the pump at a very large level. There are many ways for the steam to enter the pump, and the key reasons are as follows:

(1) The airtightness of the suction pipe is not so good that the gas enters the pump body. It is very simple to deal with this common fault, and the leaking position is completely sealed.

(2) Generally, the pump casing of the gear pump and the bearing end covers on both sides are in direct contact with hard seals. If the flatness of the surface does not meet the requirements, the pump is very easy to suck in gas when it is working; the same, the bearing of the pump There is also direct contact between the end cap and the screw cap, and gas is very easy to invade; if the screw cap is made of plastic, it will be deformed due to its destruction or temperature change, and the gas will not be tightly closed. The way to explain this kind of common fault is: When the flatness of the pump casing or pump cover is not up to the required regulations, you can put gold steel grit on the tablet computer and grind it back and forth according to the "8" line. Cut on the tool grinder so that the plan view does not exceed 5 mm. And must ensure the flatness of the plan and hole regulations.

(3) For the water pump seal, use a gear pump with a frame-type skeleton seal to develop airtightness. If the spring of the clamped lips falls off, or the oil is sealed upside down, or the lips are bruised, the rear end of the frame seal will often be under negative pressure and air will be sucked in. Generally, the frame seal can be replaced with a new frame seal.

(4) If the remaining oil in the oil sump is insufficient or the oil suction pipe port is not found to be below the oil level, the pump will suck in gas. At this time, the hydraulic oil should be drained into the car oil tank to the oil road marking; if the oil return pipe shows the oil level, Sometimes the gas will be injected back into the system software due to the momentary negative pressure in the system software, so the return oil pipe port is generally inserted below the oil level.

(5) The installation position of the melt pump is too high from the oil level, especially when the pump speed ratio is reduced, because the necessary positive emptyness of the pump suction chamber cannot be ensured, the oil is not enough to suck in gas. At this time, the absolute height of the pump and the oil should be adjusted to take into account the requirements.

(6) The degreasing filter is blocked by waste or its volume is too small, causing the friction resistance of degreasing to expand and sucking in gas; in addition, the size of the oil inlet and outlet holes is very large, and it is very likely to bring in gas. At this time, you can clean the oil filter, or choose a large-volume oil filter with moderate access specifications. At this time, not only can avoid inhaling gas, but also avoid causing noise.

2. The vibration of the melt gear pump may also be caused by gear transmission.

(1) The connection between the gear pump and the coupling is not in compliance with the regulations, which causes the gear pump to vibrate and make noise. The coupling should be adjusted in accordance with the regulations.

(2) Noise is caused by damage to the transmission gear and other components due to the waste in the oil entering the pump. The hydraulic oil should be dismantled and replaced, the filter should be lifted, and the pump should be disassembled for cleaning; the more severely damaged transmission gear should be repaired or replaced.

(3) The damage or damage of the internal parts of the pump will cause vibration and noise: if the tooth profile deviation or the circumferential pitch deviation is large, the two transmission gears are not idle, the surface roughness of the shaft journal is high, the length deviation of the common normal line, and the tooth backlash If it is too small, there is no index circle in the contact area of ​​the two-tooth transmission gear. At this time, the rotation of the removable rolling bearing is blocked, causing noise from dynamic machinery and equipment. At this time, it is necessary to dismantle and repair the gear pump and dismantle and replace the cylindrical roller bearing.

(4) The mounting clearance of the shaft sleeve is too small; the internal hole of the transmission gear and the front, rear, left, and right bearing end caps are subject to kneading. Because the burrs of the transmission gear are not carefully and clearly before installation, the welding surface will be damaged during operation and internal leakage will be caused. Large, resulting in a decrease in the total output flow; waste enters the pump and wedges into the inner hole of the transmission gear and the gap between the front and rear, left and right dampens the mating surfaces, causing the high-pressure and low-pressure chambers to be connected due to axial pull or which pipe trench to make the output The total flow is reduced. The following countermeasures should be used to repair the above-mentioned situation: disassemble the gear pump, appropriately increase the radial clearance, that is, grind the inner hole of the transmission gear; use a tool grinder to grind the front, rear, left, and right inner holes and the inner hole of the transmission gear, and eliminate the transmission gear The burrs on the top (not rounded corners); the deep specifications of the front, rear, left, and right end surfaces after cutting in the plan view are also changed, and the total width is expanded as much as possible.


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