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Influence of filter media on centrifuge vibration
 Abstract The vibration of fully automatic centrifuge is analyzed. The influence of filter medium on vibration and the way to solve the problem are put forward.
Keywords centrifuge filter media vibration
Our company in recent years installed a SGZ1000 three-foot unloading automatic centrifuge. During the trial production, it was found that the centrifuge runs smoothly at no-load and produces strong vibrations after feeding. Repeated test, all have this phenomenon. As a result, the centrifuge to conduct a comprehensive inspection, ruled out the centrifuge’s own mechanical reasons. then. Process for the ratio has been adjusted to reduce the concentration of slurry to reduce clogging, and the slurry feed line and sub
centrifuge feed the cloth after the rectification, to achieve these measures substantially continuous and uniform, but the elimination of vibration No significant results. At last. We are in the centrifuge plant polypropylene monofilament filter cloth superimposed on a layer of polyester 747 cloth. Thus basically eliminating the vibration, after nearly a year of practice, the effect is good.
1 Analysis of the reasons
1.1 Slurry Characteristics
The density of materials handled by our company is 1731kg / m. , And the larger particle size (3O ~ 40 / ~ m). Therefore, the
macro-mobility characteristics dominates. The main component of liquid petroleum ether, low viscosity, volatile. Slurry temperature is a 10 ~ 0 C, the viscosity decreases with decreasing temperature. and so. Slurry easily solid-liquid separation, with strong sedimentation.
1.2 filter media filter media using polypropylene filament filter cloth, high porosity. Than the resistance of the filter with a separation speed, easy to block, the closure effect is good and so on.
1.3 Centrifuge material distribution Slurry through the distributor to obtain a certain speed, to reach the filter surface speed again. Due to polypropylene filter cloth resistance is very small. Liquid quickly through the filter into the filtrate discharge, and the solid phase and liquid phase mobility decreased, quickly accumulate in the filter medium surface, with little flow. As the slurry settling big.So the concentration of slurry is not the same, a great difference. In fact, this situation is equivalent to the sudden bump in the feed, resulting in material distribution (thickness) is not balanced, that is caused by serious emphasis, when the most emphasis on …: the value of up to 1: 1.5 (Figure 1) . When generating a corresponding rotation of the centrifuge radially unbalanced centrifugal force, only in this case it is generally considered to cause severe vibration levels, but in fact the total vertical vibration
is accompanied by simultaneous horizontal vibration. In the radial imbalance centrifugal force. Chassis hanging on the boom will swing like a pendulum, resulting in a vertical position of the difference, repeat this exercise will lead to vertical vibration. The greater the radial unbalance force, the greater the horizontal and vertical vibrations. Vibration is generated.

2 solution 

How to eliminate or reduce this vibration? The fundamental solution is to reduce the radial imbalance centrifugal force. Centrifugal force and quality and speed is proportional to reduce the centrifuge speed while feeding can achieve this goal. But it also reduces separation efficiency. In actual production, due to the decrease of centrifugal force, the slurry falls from the lower discharge opening without separation under the action of gravity. Seriously affected the daily production.

Obviously, only the uniform distribution of materials to reduce the imbalance of centrifugal force in order to make the vibration can be completely resolved. In a normal three-legged centrifuge, we can solve this problem by feeding at rest. In a fully automatic discharge centrifuge, this obviously does not work. Know by the above analysis. The reason for the unbalanced distribution of the material is that the slurry is separated too fast on the surface of the filter net without a certain degree of fluidity. Add a layer of polyester
747 filter cloth, polyester filter cloth than the specific resistance than polypropylene filament filter cloth, it can extend the liquid phase in the filter medium residence time, so that the slurry to some extent, have a certain mobility. Under the action of centrifugal force and gravity flow to the thin layer of material. Make up for the slurry concentration caused by uneven distribution of the material. To reduce the radial imbalance centrifugal force thus eliminating the purpose of vibration. Practice has proved that the increase in separation difficulty caused by this method has little effect on production. And to avoid the centrifuge speed to reduce the leakage caused by the problem.

3 Conclusion 

In separation theory, the lower the specific resistance of the filter media. The better the effect of separation. However, in actual operation, the specific material is not analyzed in a specific way, blindly selecting a filter medium with a lower resistance than the filter medium, in order to pursue the separation speed, will adversely affect the separation machinery and its actual use. and so. In practice, we should pursue a reasonable comprehensive effect. This is the best way.