There are also instances where it makes sense to utilize ejectors and liquid ring pumps together. These systems are referred to as hybrid systems. When ejectors are staged in series with liquid ring pumps, advantages of each can be best utilized and their drawbacks mitigated. An example where a hybrid system may be attractive is when the suction pressure of the desired system is lower than what a liquid ring pump can achieve, given the service liquid supply temperature that is available. In this case using an ejector on the front end of the system can help achieve a deeper vacuum without putting the liquid ring pump in a position where it would cavitate. Another example may be an installation that is short on available steam or whose steam generation costs are very high. Utilizing a liquid ring pump at the tail end of the system in place of another stage of ejectors may in this instance be desirable as it would lower the steam consumption rate of that system.

While this article should provide a better understanding of the strengths and drawbacks of both ejectors and liquid ring pumps, it can still be difficult to determine exactly what technology and system layout is best for a particular application. In these instances, please do not hesitate to contract Graham as our engineers are available to help you work though those decisions.