Four Types Of Pump Couplers
Couplings are found in pump systems and are one of the main components of the system. Anytime you purchase a new pump, you should consider which type of pump couplers you want to put inside of the pump. The couplers connect the pump shaft to the motor shaft and send power to the pump. If you don't choose the right couplers for your specific pump, it can have a negative impact on your pump's performance overall. It may even lower the life expectancy of the pump. Not sure which type of coupler to use? This guide walks you through the main types and where they are used.
Gear Couplers
Gear couplers are the oldest design for couplers. The original model was designed in the 1890s and is still used in some applications today. The gear couplers transmit high torque at very high speeds, so they are used for large motors and pumps. The couplers are flexible and allow for a slight misalignment between the motor and pump shafts, which is ideal since misalignment can cause issues with other coupler types. However, there are some cons of using the gear couplers. They aren't good in applications with high temperatures, they can fail without warning, and they cannot be repaired. They also have a low life expectancy, require a special lube, and the pump must be shut down for periodic inspections that the couplers require.
Grid Couplers
You will most likely use grid couplers on large pumps with big motors that need high torque. The grid couplers send the torque through a spring set. These couplers are not flexible like the gear couplers and they do not allow for misalignment. They require regular lubrication to keep them working properly, and the entire system has to be shut down first and the gears disassembled. Even with constant lubrication, the grid couplers wear down after so much metal rubbing against another piece of metal. Once the metal wears down, the dynamic balance is displaced and the gears need to be replaced.
Disc Couplers
When you need couplers for medium to high torque applications, you should use disc couplers. They are usually found in marine and power generation applications. The disc couplers allow for torsional rigidity and misalignment. The disc couplers don't require lubrication like the grid or gear couplers. They don't need maintenance either, which is a huge bonus. You simply inspect it using a portable strobe light and if it shows a problem, the disc couplers can be repaired without disassembling anything. The couplers do good in temperatures as high as 750 degrees Fahrenheit. They have a high life expectancy of 20 years.
Elastometric Couplers
The elastometric couplers are one of the most used couplers. You will find them in small to medium-sized pump systems. Many people prefer them simply because they are so easy and fast to install, but they have other benefits, too. The elastometric couplers can absorb shock, end float, and misalignment.
The design for the couplers is two pieces of metal hubs attached to the motor and pump shafts. In the middle of the hubs is an insert made out of urethane or rubber, depending on the manufacturer. The inserts keep the metal from rubbing, so no lubrication is needed for the elastometric couplers. Again, this also means no maintenance like the disc couplers. The insert does need to be replaced periodically due to normal wear and tear but it is fairly simple and cheap. The drawback to using elastometric couplers is the sensitivity to high torque applications, chemicals, and high temperatures.
As long as you keep your couplers properly aligned and maintenance, they should make it to their respective life expectancy. Check the couplers frequently for signs of problems, misalignment, or broken inserts. Work with suppliers like Kims International to learn more.
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