Mr. 0 The Practical Problem Solver (December 01, 2010)

Pump alignment facts

Problem: We’re always fiddling with the alignment of one particular pump. Can we ignore it for a while?

Solution: The alignment of the pump shaft with the driver is a significant reliability factor for many applications, depending on the type of coupling and the speed of the pump.

For appropriate applications, taking the time to achieve precision alignment will pay dividends in avoided seal leakage and extended bearing life.

Conversely, precision aligning every pump may be more than is necessary. Precision alignment describes procedures that achieve tolerances less than 0.005 in. Before an assessment of the need for precision alignment is undertaken, a good understanding of shaft alignment concepts and procedures is in order.

Mr. O’s thanks for this tip go to the technical experts at the Electrical Apparatus Service Association (EASA).

Drive belt is cracking

Problem: This winter, we’re finding a few drive belts that run outdoors are failing. We’re located in western Canada, where temperatures had hit 30 below back in November.

Solution: As temperatures drop to low levels, rubber belt materials become stiffer until they reach a brittle point at about -36C (-32F). Cracking, the major cause of belt failure due to cold, occurs below this temperature.

Ways to avoid cold-temperature cracking include:

• Warming the drive enclosure or making a temporary enclosure and installing a quick-heating unit.

• Removing the belt and storing it in a warm place between uses.

• Keeping idle time to a minimum and arranging for continuous operating periods.

• Applying minimum torque or no load when starting a drive that has been idle for a long time.

• Using larger pulleys to reduce excess belt bending.

Mr. O’s thanks for this tip go to the technical experts at the Gates Corp.

Do you have a solution for a maintenance problem? Send it in and if it’s published, we’ll send you a Mr. O Problem Solver T-shirt. Include your address, telephone number, print complete details and, if possible, add a sketch to help explain your tip. Send your tips to Mr. O, Machinery & Equipment MRO, 12 Concorde Place, Suite 800, Toronto, ON M3C 4J2.