在直读式铁谱仪中，用一根玻璃沉淀管来作为玻璃基片。制备在试管中的分析油样在重力和虹吸作用下，经过毛细管而进人沉淀管。油样中的铁磁性磨粒在沉积管下面的高梯度强磁场作用下，会有序地沉积在玻璃管底部。大于5μm的大磨粒首先沉积，它们一般沉积在沉积管的入口区；1～2μm的小磨粒沉积在较远处。在大、小磨粒沉积位置分别设置有光束发射装置，光束穿过沉积管，被设置在沉积管另一侧的光电传感器所接收，可以直接测定磨粒浓度的读数。这一光电转换测量系统测出的是因磨粒沉积而覆盖沉积管底部而造成的光强衰减值，并用直读单位DL和DS在液晶数码管上直接显示。DL和DS两个光密度读数分别代表大、小磨粒的相对数量，用来表示摩擦副的磨损状态。磨粒在直读式铁谱仪中沉积管内的沉积排列由于磁场力的作用，大磨粒（＞5μm）在沉积管的入口区首先沉积，而小磨粒则按它们尺寸大小实现有序沉降、分布沉积。

In a direct reading spectrometer, a glass precipitation tube is used as a glass substrate. The analytical oil sample prepared in the test tube was injected into the precipitation tube through the capillary under gravity and siphon action. The ferromagnetic abrasive particles in the oil sample are deposited in the bottom of the glass tube under the high gradient and strong magnetic field below the deposition tube. More than 5 mu m large grains are first deposited, they generally deposited in the entrance area of the deposition tube; 1 ~ 2 m particles deposited in the distance. In large and small particles deposition position are respectively provided with a light emitting device, light beam passes through the deposition tube, photoelectric sensor is set on the other side of the deposition tube received, can direct determination of particle concentration readings. This photoelectric conversion measurement system measures the attenuation value of light intensity caused by the deposition of abrasive particles on the bottom of the deposition tube, and directly displays them on the LCD digital tube by direct reading unit DL and DS. DL and DS two optical density readings represent relatively large quantity, small particles, used to represent the wear state of the friction pairs. In the direct reading Ferrography Wear Particle Deposition tube apparatus arranged under the action of magnetic field force, large grains (> 5 m) in the entrance area of the deposition tube first deposited particles, and then according to their size to achieve the orderly settlement and distribution of deposition.