Industrial Valves

3Cavitation and Flashing

3.1 Introduction

Flow control, also known as regulation or throttling of fluids, is one application for some valves. Flow control valves adjust the amount of flow moving through the valve as well as the flow rate inside the valve; this impacts other parameters of the fluid process such as temperature, pressure, and level. Various sectors of the oil and gas industry have used globe valves extensively. Generally speaking, globe valves are covered by the American Petroleum Standard (API 602), which is titled “Gate, globe, and check valves for sizes DN 100 (4″) for the petroleum and natural gas industries.” Valves used for fluid control are susceptible to cavitation, which is a significant problem that is discussed in the following section.

3.2 Cavitation

3.2.1 What is Cavitation?

For oil and gas facilities and components such as pumps, valves, and piping, erosion or corrosion can be costly. Cavitation can be described as a type of erosion or erosion‐corrosion and is the most severe operational problem for controlling globe valves. In the oil and gas industry, T‐pattern (or tee‐pattern) globe valves (shown in Figure 3.1) are very common. A globe valve with an actuator is referred to as a control valve. The liquid flows into the valve shown in the figure from the left side and reaches the middle portion of the valve where the plug (disk) and seats are located. As the disk is off the seat, the fluid makes two 90° turns and leaves the valve from the outlet ...