Operating experience of horizontal screw centrifuge

The horizontal spiral discharge settling centrifuge (referred to as the horizontal spiral centrifuge) is an efficient centrifugal separation equipment that utilizes the solid-liquid liquid specific gravity difference and relies on the centrifugal force field to expand it several thousand times. The solid phase is settled under the centrifugal force, thus achieving solid-liquid separation and being separately discharged from the body under the action of a special mechanism.

The entire feeding and separation process is continuous, closed, and automatic.

As a high-speed rotating centrifuge, its advantages are still very obvious:

It has a great adaptability to materials and can separate a wide range of solid particle sizes ranging from 0.005 to 2mm. It can also be separated as usual even when the solid particle size is uneven;

Capable of automatic, continuous, and long-term operation, convenient maintenance, and capable of closed operation;

Large single machine production capacity, compact structure, and small footprint; It can achieve DCS control and so on.

Similarly, the fault mode is also very direct, and the vast majority of machine failures are manifested in the appearance of machine vibration. Therefore, as operators, it is necessary to have a basic understanding of machine vibration and dynamic balance. The drum and screw of the centrifuge must be balanced using dynamic balance method. Some dynamic balancing problems cannot be solved by oneself due to the lack of a balance straightening machine, such as deformation of the drum and screw. But during use, some can be prevented, such as:

Due to structural limitations, the stiffness of the centrifuge's drum and screw is not large, and they remain in a constant position for a long time. Due to their own weight, they bend and deform, causing vibration to be excited. For machines that are not used for a long time, they need to be cranked once every half a month.

Be sure to follow the prescribed startup and shutdown cleaning procedures.

Pay attention to the vibration and noise of the machine at all times, eliminate them in a timely manner, and do not work with diseases.

Common faults and solutions of horizontal screw centrifuge

Common Fault 1: Machine Blockage

The first phenomenon of centrifuge blockage is that it does not discharge slag for a long time. Under the same other feeding conditions, the discharged clear liquid gradually becomes turbid and dark, gradually approaching the color and state of the feed. With the increase of drum current and a significant decrease in drum speed, the slag discharge torque gradually increases and remains high. These all indicate the possibility of internal blockage in the centrifuge.

The slag cannot be pushed out in a timely manner, and the centrifuge drum forms a screw feeder that is blocked

In this situation, do not press the emergency button. The centrifuge is running at high speed and there is no braking device, and the emergency button cannot provide any assistance at this time.

We must first immediately cut off the feed to the centrifuge. In most cases, the centrifuge can rely on the screw pushing action to eliminate blockages. If it is not possible to push and remove blockages by itself, we should immediately reduce the speed of the drum or turn off the drum drive machine, but never turn off the screw motor. After the centrifuge drum slows down, the blocked solid residue may gradually relax and be discharged by the screw outside the machine.

For centrifuges that have indeed experienced blockage, after the drum has completely stopped rotating, we should still inject water into the machine and do everything possible to restore the operation of the spiral. As long as the screw can rotate, the centrifuge will not be truly blocked and there is still a possibility of returning to normal. Injecting water into the centrifuge and restoring spiral operation are the preferred methods for removing blockages in the centrifuge.

Common Fault 2: Abnormal Machine Vibration

The abnormal vibration of a centrifuge is a destructive force that can cause serious damage to the machine.

Machine vibration is divided into two types: chronic vibration and sudden vibration.

Chronic vibration mostly indicates wear and tear on the centrifuge, wear or detachment of external components, and gradual damage to the bearing system.

Sudden vibration often indicates internal material blockage, significant damage and detachment of internal components. In most cases, it is necessary to first check whether the slag discharge system has malfunctioned, causing solid slag accumulation to rise, and whether the clear liquid pipeline is blocked, causing liquid to spread back to the centrifuge drum body, etc.

Common Fault 3: Bearing Temperature Too High

When the bearing temperature is high, the first step is to check whether the amount of grease added to the bearing is too large, whether there is excessive vibration in the centrifuge, and whether there is abnormal noise during the bearing operation.

At the same time, we need to observe the color of the bearing waste grease. The normal color of the waste grease should be light gray. If the color of the bearing waste grease turns black, rusty yellow, or other abnormal colors, it indicates that the bearing may have been damaged and should be replaced in advance.

Regarding the issue of noise in the bearing area, not all noise indicates a problem with the machine. We pay special attention to distinguishing between a normal type of "oil layer stack ring" sharp noise. It is a grease lubricated friction component inside the bearing seat, and it emits a specific sharp sound during normal operation of the centrifuge. The characteristic is that the noise is intermittent. After performing the greasing action 1-2 times, the noise will temporarily disappear and then sound again later. This judgment relies on regular observation and continuous accumulation of experience.

Common Fault 4: Drum Manual Turning

The manual turning of the drum is one of the important methods for manually determining whether there is internal material accumulation and whether the drum can start smoothly when the centrifuge is stationary.

When we manually rotate a normal free drum, the rotation of the drum is very easy, and the drum can slow down until it stops. The stopping angle and position are random. If the rotation of the drum is very heavy, and after manually turning and releasing the hand, the drum will reverse and almost stay in the position before rotation. After repeatedly turning, each time the drum stays at an angle position, it indicates that there is solid slag accumulation inside the drum. At this time, if the drum is started to increase the speed, serious imbalance vibration will occur. When encountering this situation, please run the screw push while injecting water, empty the internal materials of the centrifuge, and then start it.