Pumps and Maintenance Part Two Flashcards
What should be done to a pump before it is shut down for a long period of time and why?
The pump should be drained to prevent damage from corrosion, sedimentation and freezing. Also, the motor disconnect switch should be opened to disconnect the motor.
What should be checked if pump bearings are running hot?
Under or over lubrication. If properly lubricated, check the alignment of the pump (or motor) and check for badly worn bearings.
What are some common causes of shear pin failure in reciprocating pumps?
Shear pins commonly fail in reciprocating pumps because of solid objects lodged under the piston, a clogged discharge line or a stuck wedged valve.
Why would you use a stethoscope to check an electric motor?
To listen to an electric motor for whines, gratings or there is an uneven noise.
How would you clean belts on a belt drive system?
Belts are cleaned with a rag moistened with a non-oil solvent.
How can you determine if a chain in a chain-drive unit has the proper slack?
The proper slack in a chain can be achieved when a slight sag or looseness is observed on the -RETURN- run of the chain.
What maintenance is required on gate valves?
Oiling, tightening or replacing the stem stuffing box packing.
What maintenance is required on sluice gates?
Testing for proper operation, cleaning and painting, and adusting for proper clearance.
How would you maintain a portable gas detector?
Be sure the battery is charged periodically, and calibrate using known standard gas concentrations obtained from the detector manufacturer.
Why should inactive gate valves be operated periodically?
To prevent sticking.
What methods are available for clearing a plugged pipe?
They may be cleared by using pressure methods, cutting tools, high-velocity pressure units and, as a last resort, dismantling the plugged section and removing the obstruction.
How would you clean a plugged pump?
To clean a plugged pump, isolate the pump from the remainder of the plant by valving off the plugged pump and tagging and locking out the power supply to the pump. Remove the pump inspection plate and remove material causing blockage.
What is flow measurement?
The determination of the -RATE- of flow past a certain point, such as the inlet to the head-works structure of a treatment plant. Flow is measured and recorded as quantity (gallons or cubic feet) moving past a point during a specific time interval (seconds, minutes, hours or days). Thus, we obtain a flow rate or quantity in cu ft./sec or MGD.
What is the basic flow formula?
Quantity = cross sectional area x velocity, -OR- q = AxV.
If the flow meter does not read properly, what items should be checked as potential causes of error?
Foreign objects fouling the system or the meter may not be installed in the intended location. Also, check the primary sensor, transmitter, receiver and power supply.
