Abnormal vibration of the centrifuge shaft, seeking help
Thread Content
For the MCO804 air compressor manufactured by Shenyang Blower, our unit is experiencing a gradual increase in vibration in its front support. The vibration level rose from around 20 in April to 55 at present. It has been observed that there are significant fluctuations in the temperature of the process gas over short periods of time – when the temperature is low, the vibration is low as well; conversely, there are no significant changes in oil temperature, oil pressure, outlet pressure of the unit, or load. We would appreciate it if experts could explain what this phenomenon is
The topic is centrifuges; the content deals with air compressors – it’s overwhelming
The issue is analyzed from three aspects: 1. Design problems – the range of temperature variations considered is too narrow, which does not correspond to reality, and the consideration was inadequate； 2. Quotation issues: When the quotation was requested initially, the basic conditions were not specified properly, which led to an inappropriate selection of the machine units ； 3. Manufacturing issues: The design requirements were not strictly followed during the manufacturing process. Suggestion for handling: Seek advice from SHENGU.
This post was last edited by Shutong on 2020-7-16 07:09. Please explain the concepts of centrifuges and centrifugal compressors in the reply above
The MCO804 compressor is a multi-stage centrifugal compressor with a horizontally split, externally mounted cantilevered casing. A compressor mainly consists of a stator (housing, diaphragm, seals, balance disk seals, end caps), a rotor (shaft, impeller, sleeve, balance disk, shaft sleeve, half coupling, etc.), as well as support bearings, thrust bearings, and shaft end seals. Auxiliary systems include the dry gas seal system, lubrication oil system, and electrical and instrumentation control system.
The MCO804 features a horizontal split design with an external cantilevered volute, three compression stages and four impellers; the diameter of the first-stage impeller is Φ900mm. The first stage has a cantilevered structure, while the second and third stage impellers are arranged back to back.
Definition: A centrifuge is a machine that uses centrifugal force to separate the various components in mixtures of liquids and solid particles, or of liquids together. Working principle: Centrifuges are primarily used to separate solid particles from liquids in a suspension ； Or to separate two liquids of different densities that are immiscible with each other in a suspension (for example, separating cream from milk) ； It can also be used to remove liquid from wet solids, such as spinning wet clothes in a washing machine ； Special supersonic tubular separators can also separate gas mixtures with different densities ； Taking advantage of the fact that solid particles with different densities or particle sizes have varying sedimentation speeds in a liquid, some sedimentation centrifuges can also sort solid particles based on their density or particle size
The topic of the post is centrifuges, while the question concerns centrifugal compressors; I’m not sure why there’s a mismatch between the topic and the content
First, let’s make some guesses regarding the various elements of the question, for reference only :) 1. Can “support vibration” be understood as the vertical vibration of the equipment’s foundation? ““The vibration in the front support has been increasing gradually.” The most likely cause of this phenomenon is an imbalance in dynamic balance. In other words, it is caused by scale buildup on the impeller. It is also possible that vibrations are caused by the gradual increase in bearing clearance. It is mainly due to the phrase “has been growing slowly” in “the vibration of the front support has been growing slowly”. 2. Is “from around 20 to the current 55” the measured vibration value? It’s best to indicate the unit. 3. Are the “ten points” for the temperature of the process gases below the range of temperature variation? “Low temperature means low vibration,” Is the factor of low temperature due to human control or changes in atmospheric temperature? Please make it explicit. One final piece of advice: it’s best to phrase questions in a more standardized manner, as this helps facilitate discussions on those questions; for your reference.
I work at Shenmu. Based on your description, 1. since the vibration increases gradually, it must be that impurities accumulate on the surface of the impeller during operation, disrupting the original balance.
I work at Shenmu. Based on your description, 1. since the vibration increases gradually, it must be that impurities accumulate on the surface of the impeller during operation, disrupting the original balance. This situation will not keep increasing. 2. Vibration increases as the temperature rises. According to fluid dynamics, at higher temperatures, gas molecules are more active, making it more difficult to compress the gas; as a result, minor rotational stall occurs inside the compressor. This is my rough guess based on your question; a detailed analysis will be necessary on-site.