Our reliable approach to Ejector Design
All Transvac Ejectors operate according to their ‘design point’, provided the process conditions (at the motive, suction and discharge connections of the Ejector) are as expected.
However, many industrial processes cannot provide completely ‘fixed’ process conditions at the motive, suction and discharge connections of the Ejector. There will be some ‘natural’ variations in flow, pressure, temperature or composition of the process streams. These variations will have some effect upon the performance of an Ejector as they move further away from the design point.
To address this, Transvac takes a safe, conservative approach to our process design by ensuring the Ejector will still operate as required – even in the ‘worst operating case’. To do this, we work with our Clients to establish, for each process stream, what (if any) variations can be expected. In simple terms, to determine this ‘worst operating case’ for the Ejector, we ask;
- What is the most ‘work’ your process requires the Ejector to do?
- What is the least amount of (motive) energy your process will provide to drive the Ejector?
These two questions can be answered by understanding;
- Lowest Motive Pressure (least amount of motive energy)
- Lowest Motive Flow (least amount of motive energy)
- Highest Suction Flow (most work for the Ejector)
- Lowest Suction Pressure (most work for the Ejector)
- Highest Discharge Pressure (most work for the Ejector)
- Variations in Motive and Suction Composition (effect varies by application)
- Variations in Motive and Suction Temperature (effect varies by application)
Be cautious, but realistic.
When determining ‘worst case’ process data for your Ejector application, it is important to be realistic in your assessment. It can be tempting to add extra ‘safety margin’ above and beyond the realistic worst case for each respective data point. This approach may result in an Ejector design that demands far more Motive energy than is actually required – worse still, it could make the whole Ejector application not viable, due to a lack of available Motive stream. Even if a Motive stream is available, in normal realistic operating conditions, the Ejector would be operating in a less efficient manner, needlessly wasting valuable energy.