Which part is NOT typically used in a pump to increase pressure?

In a pump system, various components work together to increase the pressure of the fluid being pumped. The impeller, volute, and casing all play crucial roles in this process. The impeller is a rotating component that imparts kinetic energy to the fluid, thus increasing its velocity and pressure as it exits the pump. The volute is designed to convert the kinetic energy from the impeller into pressure by allowing the fluid to expand and slow down, further increasing pressure in a controlled manner. The casing serves to contain the fluid and maintain pressure while also facilitating the flow of the fluid through the pump.

On the other hand, the throttle valve is a control device rather than a pressure-increasing component. Its primary function is to regulate the flow of the fluid by constricting the passage, which can result in a drop in pressure downstream of the valve. While it plays a significant role in managing system pressure and flow, it does not contribute to increasing the pressure within the pump itself. Therefore, it is not categorized as a component that typically builds pressure in a pump system.