Power transmission is an integral part of any mechanical process. Not only does it indicate the strength of a mechanical element, but it also has countless applications in all industries. For example, pump couplings are the mechanical devices employed for power transmission between the pump shafts.

Pump couplings are further categorized into different types based on their application. Still, their key purpose is transferring power between the pump shafts to compensate for any misalignment.

Types and Uses of Couplings

Following are some of the main types of couplings along with their functions:

1. Hydraulic Pump Couplings

Hydraulic pump couplings, as the name suggests, are couplings specifically designed for hydraulic pumps. The shafts installed in the hydraulic pumps provide a power transmission channel through these couplings. Moreover, they are installed in the pumps to provide smooth and hassle-free functioning and rotation of the shafts.

1. Jaw Couplings

Jaw coupling is a general-purpose power transmission coupling that can also be employed in motion control (servo) applications. Joining two shafts transmits torque while attenuating system vibrations and accommodating misalignment, safeguarding other parts from harm.

1. Sleeve Coupling

A Sleeve coupling is made up of cast iron. It is composed of an empty cylinder whose inner diameter matches the shaft's (sleeve). With the aid of a gib head key, it is secured over the ends of the two shafts. A key and a sleeve are used to transfer power from one shaft to another.

1. Disc Coupling

A disc coupling is a flexible shaft coupling that transfers torque tangentially on a shared bolt circle from a driving to a driven bolt. Thin stainless steel discs stacked in a pack transmit this torque between the bolts. These couplings' flexibility is due to the material between the bolts being deformed. Disk couplings can often manage speeds up to 10,000 rpm and are ideal for high-performance motion control applications.

1. Diaphragm Coupling

A diaphragm coupling is composed of one or more metallic membranes connected at the driving flange's outside diameter. They transmit torque radially through the membrane to an attachment's internal diameter.

How to Select the Right Coupling

It is very important to choose the coupling consistent with the application depending on the given information. There are manuals and guides for the selection process of the right coupling designed by the manufacturers. Not selecting the right coupling or not considering the required factors can not only damage the shaft to which it is attached but can affect the overall functioning of the mechanical device.

The following is the process of choosing the right coupling:

● Horsepower and Operating Speed: Torque must be calculated using the motor's horsepower and running speed to ensure that the coupling's maximum torque and RPM ratings are appropriate. Depending on the brand and coupling type, these ratings will vary.

● Working temperature: The materials a coupling is made of determining the minimum and maximum operating temperatures. On occasion, the components' thermal expansion and contraction, when coupled together, can also be a problem.

● Space restrictions: Each coupling has a range of DBSEs (Distance Between Shaft Ends) that it can accept, and the design of the pumping apparatus will determine the DBSEs that are needed or that will be most advantageous.

● Axial travel and criteria for tolerating misalignment: Depending on several variables, the amount of misalignment that certain couplings can tolerate varies. An excessive amount of misalignment will cause the coupling to fail prematurely.