Pumps are the second most commonly used industrial equipment after electric motors. Currently, millions of pumps worldwide are in operation, conveying tens of thousands of different liquids. Selecting the appropriate pump from the multitude of available types is a highly complex task.
The pump selection process is largely about matching the capabilities of a specific pump with the system requirements and the characteristics of the liquid to be pumped. In this article, we will begin by examining the properties of the pumped fluid and the user's requirements, then proceed to discuss specific pump selection.
Basic Requirements
In any application, the first step is to understand the user's fundamental requirements for the pump. These include: inlet conditions, required flow rate, pressure differential, temperature, and fluid characteristics such as viscosity, abrasiveness, shear sensitivity, and corrosiveness. All these conditions must be fully determined before selecting a pump.
A pump operates optimally only under correct suction conditions. In fact, the most significant challenges encountered with pumps often stem from improper suction conditions. Since a pump's ability to discharge fluid far exceeds its suction capacity, inlet conditions must be maintained within the pump's operational limits.
Pressure differential is also a critical factor, particularly from the perspectives of energy efficiency and pump lifespan. While using smaller pipe diameters and longer pipeline lengths can reduce initial system costs, they may also result in higher pressure differentials for the pump. This increased pressure differential translates into energy consumption and can potentially shorten the pump's lifespan, leading to higher operating costs and lower efficiency.
The required liquid properties are typically known, and the critical aspect lies in understanding how a given pump affects these properties. The vast majority of users expect the pumped liquid to exit the pump in the same condition as when it entered. Material compatibility, viscosity, shear sensitivity, and the presence of specific substances or solids are all of paramount importance for proper pump selection.
