The effect of centrifugal pump mechanical seal device -

according to China's petrochemical industry statistics, more than 80% of the shenzhen adopts mechanical seal centrifugal pump manufacturer. Due to the different working conditions, the centrifugal water pump in the process of conveying material, frequently, materials of mechanical seal leakage, environmental pollution, waste of energy.

is one of the main vulnerable parts of centrifugal pump mechanical seal, so most of pump failure is caused by the seal failure. According to statistics, mechanical seal failure caused by pump failure accounted for more than 50% of the equipment failure rate, so it is necessary to analyze the centrifugal pump mechanical seal leakage and to improve, in order to reduce the failure rate of the pump.

a, the working principle of centrifugal pump, and the role of the mechanical seal device

a centrifugal pump with a high-speed rotating impeller motor and coupling. The liquid between the blades are driven leaf. Under the action of centrifugal force, pump the liquid from the center to throw around. When pump the liquid from the impeller center to the edge, the low pressure area in the center. Because of the liquid before entering the pump pressure is greater than the pump inlet pressure, under the action of pressure difference, liquid through continuous, in the suction pump suction pipe is to supplement the discharged liquid position. As long as the impeller to rotate, the liquid will be overtaken by suction and discharge.

when the pump shaft through the pump shell, when the gap between moving parts and parts, pump the liquid will leak out of the pump from the gap. If is vacuum suction side, the outside air leakage into the pump, the serious influence the operation of the pump. In order to reduce the leakage, the shaft end sealing device is generally installed in a static clearance. The shaft sealing device is an important component of the centrifugal pump, is directly related to the normal operation of the centrifugal water pump. Now generally adopts mechanical seal shaft sealing device.

2, the principle of mechanical seal

mechanical seal is a kind of axial end face sealing device, it relies on elastic element, and intermediate pressure compression static ring end face seal preload pressure of elastic element to realize seal.

mechanical seals are usually made of static ring, ring, compaction of components and packing element. Ring and static ring end face to form a pair of friction pair, ring through the liquid pressure in the sealed chamber to static ring end face of the pressure on the two rings on the end face of the two rings on the end face of the appropriate specific pressure, and maintain a very thin liquid film to achieve the purpose of sealing.

when the pump is not running, pressure produced by extrusion device can ensure the pump end face each other contact, to ensure that the sealing medium not leak, and to prevent debris from getting into the seals. The space between the sealing ring seal ring and shaft, seal static ring and the space between the gland, and buffer pump vibration and shock. Mechanical seal in the actual operation is not an isolated parts, it is combined with the other parts of the pump running.

three, mechanical seal auxiliary facilities - — Flusher

flushing device is the most important auxiliary facilities of mechanical seal. In the process of pump operation, must flush sealed cavity formed deposit or impurities. Otherwise, the static mechanical seal ring will lose its floatability, spring will be due to the crystallization and precipitation of granular impurities. What's more, wear particles and impurities into the friction pair will aggravate the wear, lead to mechanical seal failure quickly. Therefore, in general, the pump mechanical seal shall be flush.