There are several types of check valves available for the prevention of reverse flow in a hydraulic system. The simplest and often most reliable are the ubiquitous swing check valves, which should be carefully selected to ensure that their operational characteristics (such as closing time) are sufficient for the transient flow reversals that can occur in the system. Some transient flow reversal conditions can occur very rapidly; thus, if a check valve cannot respond quickly enough, it may slam closed and cause the valve or piping to fail.

Check valves that have moving discs and parts of significant mass have a higher inertia and therefore tend to close more slowly upon flow reversal. Check valves with lighter checking mechanisms have less inertia and therefore close more quickly. External counterweights present on some check valves (such as swing check valves) assist the valve closing following stoppage of flow. However, for systems that experience very rapid transient flow reversal, the additional inertia of the counterweight can slow the closing time of the valve. Spring-loaded check valves can be used to reduce closing time, but these valves have higher head loss characteristics and can induce an oscillatory phenomenon during some flow conditions.

It is important that the modeler understand the closing characteristics of the check valves being used. For example, ball check valves tend to close slowly, swing check valves close somewhat faster (unless they are adjusted otherwise), and nozzle check valves have the shortest closing times. Modeling the transient event with closing times corresponding to different types of check valves can indicate if a more expensive nozzle-type valve is worthwhile.

The following attributes describe the check valve behavior: