Chemical centrifugal pump operation maintenance Notes: (1) lubrication centrifugal pump in operation, due to be transported medium, water and other substances may change into the tank, affecting the normal operation of the pump, therefore, should always check the quality of the lubricant and Oil level. Check the quality of lubricants can be observed with the naked eye and regular sampling and analysis. The amount of oil, as can be seen from the oil level mark. New pump running oil should be changed after a week, when the overhaul of the bearing pump should be changed. Because the new bearing and shaft running run-time foreign matter into the oil, you must change oil. After the oil change every quarter. Chemical pump used in grease and lubricants, to meet the quality requirements. (2) vibration pump in operation, due to the quality of spare parts and maintenance of poor quality, improper operation or pipeline vibration and other reasons, often produce vibration. If the vibration exceeds the allowable value, stop and overhaul to avoid damaging the machine. Table Centrifugal Pump Vibration Allowable Range Speed ​​/ r / min Bimodal Amplitude / mm Speed ​​/ r / min Bimodal Amplitude / mm Rolling Bearings Plain Bearings Rolling Bearings Plain Bearings 1800 or less 1801 to 4500 4501 to 6000 6000 or more Measurement Units Housing Shaft (3 ) Bearing temperature rise pump during operation, if the bearing temperature rise quickly, the bearing temperature is too high after the steady temperature rise, indicating the bearing in the manufacture or installation of quality problems; or bearing grease (grease) quality, quantity or lubrication non-compliant. If not handled in time, there is a risk of burning bearings. Centrifugal pump bearing temperature allowable value: Sliding bearing (4) Centrifugal pump performance Pump during operation, if no change in the liquid source, import and export pipeline valve opening unchanged, and the flow or import and export pressure has changed, indicating that There is a problem in the pump or in the pipe. To quickly identify the reasons, in time to rule out. Otherwise, it will have adverse consequences. Figure 2-44 for the centrifugal pump performance curve. Figure 2-44 in the curve is running at rated speed conditions, the performance analysis is as follows. There is a certain dependency between the flow rate Qv and the head H, which varies easily along the curve. Corresponding to a certain system resistance, there is a certain set of flow and lift. For example, the corresponding system resistance 07-1, there is flow gv, lift the greater the resistance of the H1 system, the greater the pump head, and the smaller the flow. For example, 07-2 resistance is greater than 107-1 resistance, then H2> H1, qv2 system resistance size, by adjusting the pump inlet and outlet valve opening to achieve. For a given pump system, when the outlet valve is fully open, the resistance of the system is minimized while the corresponding flow rate is maximum with the smallest lift and the highest power. When the outlet valve is shut down, the system resistance reaches a maximum value. At this point the flow is zero, the maximum lift (for a limited value), the minimum power. This can be summarized as follows. ①centrifugal pump at start-up, in order to avoid overloading the prime mover, the outlet valve should be closed first, and then slowly open the pump after the start. In this way, when the prime mover is started, a large starting load and a high power required by the pump when the outlet valve is fully opened can be avoided, causing the prime mover to overload. ② As long as the pump chamber is full of liquid (to avoid seal rings, shaft seals and other dry friction), the centrifugal pump in the outlet valve is closed, allowing a short period of operation. Unless the limited liquid in the pump chamber, under the action of the rotating impeller, the temperature rise is very fast and brings some adverse effects on the pump, there is no adverse effect on the prime mover. At this time, the prime mover load the lightest. ③ operation, you can adjust the outlet valve opening centrifugal pump performance within the scope of any set of flow and head. However, the pump is most efficient when it runs at the design operating point; the farther away from the design operating point, the lower the efficiency. (5) Unit sound pump sound emitted in the operation, some are normal, while others are not normal. For abnormal sound, to identify the reasons, in a timely manner to eliminate. Caused abnormal pump sound, roughly the following reasons. ①fluid reasons such as centrifugal pump inlet flow is insufficient, resulting in cavitation, noise; pump outlet pipeline nest gas, causing water hammer, issued by the impact of sound and so on. ② mechanical reasons bearing quality does not meet the requirements or damage; pump static and dynamic part of the gap is not suitable for causing friction; shaft bending caused by internal friction; parts damaged off; pump into the foreign body and so on.