WASTEWATER
By Rick Lallish
When connecting a pump and a motor, what are the two types of misalignment?
A. Polarity and conduction
B. Linear and polar
C. Parallel and angular
D. Vertical and horizontal
Answer: C. Proper alignment of pumps to motors is a critical concern. Misalignment will cause premature pump or motor failure. It is a frequent cause of vibration, and it may cause catastrophic related failures, such as broken shafts. Parallel alignment occurs when the pump and motor shafts are parallel to each other. Angular alignment occurs when the centerlines are not parallel but form an angle. More information may be found in the OWP, California State University at Sacramento textbook: Operation of Wastewater Treatment Plants Vol. 2 (7th ed.), Chapter 15.
DRINKING WATER
By Drew Hoelscher
What is adjusted to control leakage from the stuffing box of a pump?
A. Mechanical seal gland
B. Mechanical seal
C. Packing gland
D. Lantern ring
Answer: C. Packing glands are located on the back of the stuffing box and are designed to apply pressure to the mechanical packing. This pressure is necessary to ensure that the packing is pressed against the shaft and the inside of the stuffing box. The operator needs to make small adjustments to the packing gland as the packing becomes worn. It is also important to note that newly replaced packing will require the packing gland to be fairly loose (finger tight) during initial startup of the pump.
About the authors
Rick Lallish is water pollution control program director and Drew Hoelscher is program director of drinking water operations at the Environmental Resources Training Center of Southern Illinois University Edwardsville.
