Your Guide to Pumps and Compressors

Pumps and compressors are both widely used in industrial and commercial applications. Although both machines facilitate the movement of fluids through a transmission system, they differ in operating principles and media compatibility. By understanding the mechanics of these elements, buyers can best choose a product commensurate with their individual needs. In this blog, we do a deep dive into pumps and compressors, highlighting their function, uses, and distinguishing factors.

Pumps are devices that move fluids through a transmission apparatus. When discussing fluids in the context of industrial components, it is important to note that the term encompasses both condensed-phase (liquids) and non-condensed-phase (gasses) matter, since both follow the laws of fluid mechanics. Positive-displacement pumps employ a reciprocating piston, plunger, or diaphragm to draw and discharge a fluid. Meanwhile, centrifugal pumps transport media by means of rotational energy supplied from an associated energy source. For high-flow applications, an axial flow pump is commonly used. This variant relies on an axial impeller to transport fluids, which is supported by a right-angle drive shaft.

When discussing pump performance, it is necessary to understand the mathematical relationship between variables of interest. For example, the unitless quantity of efficiency can be calculated using the formula η=PQΔp?, where Q is the flow rate of the fluid, ΔP is the pressure produced by the pump, and p represents the power input. At any point along the transmission system, the velocity (V) of a fluid can also be calculated using V=Q/A, where Q is the flow rate and A is the pipe area. Finally, the change in pump temperature is equal to P/Cp*Q*p, where P is the break-power modified by pump efficiency, Cp is the specific heat of the matter being transported, Q is the flow rate, and p is the fluid density.

Unlike pumps which primarily deal with condensed-phase fluids, compressors are used to increase the pressure of a gas. Industrial compressors have the unique ability to be staged in which several units are strategically placed along a transmission system to continually increase the pressure of the gas as it travels. With each consecutive pass of the media, the temperature will also increase due to Gay-Lussac's law which states that the temperature of a compressible fluid is proportional to its temperature. Depending on the application, engineers may elect to also install one or more cooling stages.

One of the most critical metrics to consider when implementing a compressor into a system is the effect of cooling during the compression process. Although the rigorous mathematical definitions of each of the following processes will not be covered, it is important to note that an isentropic process involves no cooling, polytropic provides some cooling, and isothermal delivers maximal cooling. Another factor determining the power and efficiency of compressors is the type of drive motor associated with its installation, whether it be gas, steam, electric, or diesel. When choosing a product for a particular application, it is necessary to compare these power delivery options and decide which is an appropriate fit based on the operating environment and operational demand.

Whether you are in the market for a high-quality pump or compression device, Stacked Industrials has you covered with rapid turnaround times and competitive pricing on an inventory of over 2 billion components. We invite you to browse our several parts catalogs at your leisure, keeping in mind that you may initiate the purchasing process for any listed item using our Instant RFQ service. Our dedicated team of account managers are on standby 24/7x365 for customers, and they would be happy to provide you with a customized solution within 15 minutes or less. If you have questions about any of our products or the services we provide, please reach out by phone or email.