Centrifugal Water Pump Operation

Operation of centrifugal pump

(1) Inspection of centrifugal pump

①Observe the pressure gauge: the pressure pointer is within the red line range, the pointer does not swing, and the total range of the pressure gauge is 1.5 to 3 times the pressure indication. [Pressure includes the outlet pressure gauge and the seal oil pressure gauge]

②Observe the current: the current pointer does not swing.

③Observe the circulating water: the circulating water inlet and outlet manual valves are open, and the rotor in the sight glass is in a rotating state.

④Observe the lubricating oil: there is oil gas coming out of the oil tank of the oil mist lubrication system; check the lubrication window of the oil mist lubrication system, the liquid level is between 1/2-2/3, and the lubricating oil is transparent and not turbid.

⑤Measure temperature: check the temperature of the front and rear bearings of the pump (at least 3 points), the motor end face temperature, and the motor body temperature.

⑥Measure vibration: check the vibration of the front and rear bearings of the pump (both horizontal and vertical), and the motor end face vibration (both horizontal and vertical).

⑦Check the leakage of the front and rear seals. ⑧ Check the preheating of the standby pump: the preheating line is turned on and the flow is normal. Check that the preheating line temperature is close to the oil temperature.

⑨ Listen to the sound, including the sound of the wheel, bearing, pump housing, and motor.

(2) Steps for switching hot oil centrifugal pumps.

① Confirm that the preheating is normal; [the preheating line temperature is close to the medium temperature]

② Check the anchor bolts, circulating water, oil mist lubrication (lubricating oil), etc.

③ Turn the pump over 540°. [Check for sticking]

④ Close the preheating line valve.

⑤ Start the standby pump motor.

⑥ After checking that the seal and vibration of the pump are normal, observe that the pump outlet pressure and current are normal, and then slowly open the outlet valve of the standby pump.

⑦ While slowly opening the outlet valve of the standby pump, gradually close the outlet valve of the original running pump to minimize the fluctuation of flow and pressure.

⑧ After the standby pump to be activated is running normally, confirm the pump flow. After it is normal, wait for the outlet valve of the switched pump to be closed and stop the pump.

⑨ Check the pump's seal, vibration, pump outlet pressure, current, etc. and confirm that there is no abnormality.

⑩ Open the preheating line valve of the stopped pump.

(3) High-temperature oil pump exits maintenance.

① Contact the electrician and shut down the pump.

② Close the pump inlet and outlet valves and confirm that they are tightly closed; [the high-temperature oil pump also needs to close the oil sealing valve and the white oil tank oil sealing valve, and slightly open the inlet and outlet cross-line] Close the pump circulating cooling water system water supply valve and return valve.

③ Observe the pump pressure to determine whether the pump has internal leakage in the inlet and outlet valves.

④Open the pump outlet 106# line and sweep the 106# line; [When sweeping the line, you need to turn the wheel several times] ⑤Open the inlet pump sweeping steam and sweep the line; [When sweeping the line, you need to pay attention to the running status of the running pump. If there is vacuum, immediately close the sweeping steam valve] ⑥Sweep the line for 5min-20min, check the pump outlet or pump body vent, and check whether the sweeping line is clean until the venting steam is oil-free.

(4) Preheat the pump.

①Open the vent, drain the water in the pump body, and close all vents; check the anchor bolts.

②Turn the wheel and check the cranking of the pump; (During the preheating process, it is required to turn the wheel 360°/15min each time).

③Slightly open the preheating line and the inlet valve to keep the pump flowing, observe the running status of the running pump, and control the preheating pump heating rate ≯50℃/h. ④ Confirm that the temperature difference between the pump body and the medium is less than 50℃, and fully open the preheating valve and the inlet valve.

(5) Preheating of high-temperature heavy oil centrifugal pump.

① Open the vent, drain the water in the pump body, and close all vents; check the anchor bolts.

② Turn the machine and check the cranking of the pump; (During the preheating process, the cranking is required to be 360°/15min).

③ Open the sealing oil of the high-temperature pump and inject the sealing oil into the front and rear seals.

④ Open the 106# line valve at the pump outlet, measure the temperature with a temperature gun, compare the front and rear temperatures, and close the small valve after the temperature reaches 100℃ to maintain flow.

⑤ Open the 106# line valve at the pump inlet (preheating 106# line valve), measure the temperature with a temperature gun, compare the front and rear temperatures, and close the small valve after the temperature reaches 100℃ to maintain flow.

⑥ Close the sealing oil, introduce hot oil into the pump from the preheating line, and withdraw the oil from the heavy dirty oil line or quenching oil line at the pump inlet.

⑦ After 30 minutes, open the pump inlet to vent (keep the first steam valve closed, the second valve and the vent valve open), close the valve after seeing hot oil (use a temperature gun to measure the temperature, the vent line temperature is required to be above 100℃), use steam to sweep the vent line and close all steam-related valves.

⑧ Monitor the temperature at the flange in front of the pump inlet valve and record the temperature.

⑨ Close the inlet and outlet 106# line valves; close the main oil sealing valve.

⑩ Slightly open the preheating line, hold the pump body pressure to 0.4MPa, and then close the preheating line valve.

⑪ Slowly open the pump inlet valve, and stop opening the pump inlet valve immediately after the pump body pressure drops suddenly.

⑫ Slightly open the preheating line to allow it to flow; [If the running pump is evacuated, immediately close the pump outlet valve and stop preheating. At the same time, close the outlet valve of the running pump, and wait for the pressure to rise before opening the valve. ⑬ Use a temperature gun to monitor the temperature at the flange in front of the pump inlet valve, compare, and observe the temperature rise of the pump inlet; [When the temperature at each point on the flange in front of the inlet valve is lower than 105℃, it is forbidden to open the inlet valve)] ⑭ Open the inlet valve, there is no vacuum, open the preheating line valve for the second time, and observe the machine pump pressure. If the machine pump pressure rises, close the small valve to keep the pump body without pressure. ⑮ Confirm that the temperature difference between the pump body and the medium is less than 50℃, and fully open the preheating valve and the inlet valve. ⑯ Add sealing oil and fill the white oil tank with white oil. (6) Preparations before starting the centrifugal pump

① Check whether the pump body and inlet and outlet pipelines, auxiliary pipelines, valves, flanges, joints, and pressure gauges are leaking, whether the anchor screws and motor grounding wires are loose, whether the coupling is connected properly, and whether the center line of the pump shaft is aligned (the hot oil pump should be aligned after the pump is preheated).

② Check whether the pump outlet pressure gauge and the oil seal pressure gauge are installed well, whether the range selection is appropriate, and whether the pressure gauge, ammeter, and oil tank oil level are marked with a safety red line.

③ Fill the bearing oil tank with qualified lubricating oil according to the pump lubricating oil usage specifications and the three-stage filtration method. The oil tank must be cleaned with lubricating oil and the oil level is added to between 1/3 and 2/3 of the oil mark. Check whether the oil slinger ring has fallen off and whether the water baffle screws are tightened.

④ Check whether the rotor is flexible and easy, whether there is any abnormal sound and metal impact sound in the pump body, check whether the rotation direction of the motor is consistent with the rotation direction of the pump, and install the wheel guard. ⑤ Turn on the cooling water and sealing oil to make them circulate smoothly, adjust the cooling water flow and sealing oil pressure (the sealing oil pressure is generally 0.5-1.0kg/cm2 higher than the pump inlet pressure. If there is no pressure gauge on the pump inlet line, the appropriate sealing oil pressure should be found out in actual operation), and check the oil content in the cooling water leaking from the front and rear glands of the pump shaft. ⑥ Prime the pump, open the pump inlet valve and outlet pressure gauge condensate valve, and introduce oil to replace the air and moisture in the pump body (if the hot oil pump is disassembled for inspection, the fitter uses sealing oil to inject into the pump casing to check the leakage of the end cover flange and end face seal, and the sealing oil should be completely replaced out of the pump). Create a new process to introduce the oil tank pump before starting the pump. If it is not timely to replace the condensate pipeline from the pump outlet pressure, you can also open the pump outlet valve to push the outlet pipeline, and then close the pump outlet valve to start the pump, but it must be stated that preheating the standby pump or switching the pump is absolutely not allowed to do so, otherwise it will cause the running pump to be emptied.

⑦ The hot oil pump must be preheated before starting, and the preheating must be slow. The heating rate must not exceed 50℃/hour. Preheat to a temperature difference of 40-60℃ with the operating temperature. During the preheating process, turn the pump 180℃ every 10 minutes.

⑧Contact the electrician to supply power. For newly installed pumps or pumps after overhaul, start the pump to check whether the rotation direction of the pump is normal. If it is reversed, stop the pump immediately and contact the electrician to "change phase" of the cable head wiring.

⑨Prepare the oil pot, tools, thermometer, and stethoscope.

⑩When starting, there should be an operator present, and the process has been changed. The regulating valve has been remotely opened to a certain degree. The instrument worker has been contacted to start the primary meter and open the pump outlet pressure gauge pressure valve. If it is a newly installed pump or a pump after overhaul, it is necessary to contact the electrician and fitter to the site