渣浆泵泵轴穿出泵壳时，在轴与壳之间存在着间隙，如不采取措施，间隙处就会有泄漏。当间隙处的液体压力大于大气压力(如单吸式离心泵)时，泵壳内的高压水就会通过此间隙向外大量泄漏;当间隙处的液体压力为真空(如双吸式离心泵)时，则大气就会从间隙处漏人泵内，从而降低泵的吸水性能。为此，需在轴与壳之间的间隙处设置密封装置，称之为轴封。目前，应用较多的轴封装置有填料密封、机械密封。

When the slurry pump shaft passes through the pump casing, there is a gap between the shaft and the casing. If no measures are taken, there will be leakage at the gap. When the liquid pressure at the gap is greater than atmospheric pressure (such as a single suction centrifugal pump), the high-pressure water inside the pump casing will leak a large amount outward through this gap; When the liquid pressure at the gap is vacuum (such as a double suction centrifugal pump), the atmosphere will leak into the pump from the gap, thereby reducing the pump's suction performance. To achieve this, a sealing device called a shaft seal needs to be installed at the gap between the shaft and the shell. At present, the commonly used shaft sealing devices include packing seals and mechanical seals.