Energy-saving principle of the stepless air volume control system

The adjustment of the reciprocating machine can be achieved through a combination of override control and stepless air volume regulation; the two methods operate independently without interfering with each other. Override control involves manually regulating the compressor load using the stepless air volume system, with the pressure being controlled by a return valve. Continuous air volume control refers to the situation where the return valve is fully closed, and the continuous air volume control system automatically adjusts the load and pressure based on the load of the device. Due to the adjustment dead zone of the variable air volume control system, that is, below around 20% load the system is unable to make adjustments; in such cases, super-pool control can be used instead. Therefore, it can switch between override and variable air volume depending on the load level. Therefore, I believe that even when there is backpressure downstream, as long as the compressor load is at least 20%, the variable airflow control system should be able to adjust the load while simultaneously controlling the outlet pressure, thereby truly achieving energy savings through backflow.

Thank you for your guidance, but I have two new questions. They’re rather simple, and I hope you’ll still be kind enough to help me out. Thank you! First, when the load is above 20% and backpressure occurs downstream without switching to override control, if one wants to resolve this backpressure issue, can the cylinder be considered as a passage? If so, how can the problem of the exhaust valve opening be addressed? If not, is it possible to rely only on the return valve? ； Second, when the compressor load is below 20%, the compressor itself loses much of its significance. Is this a situation that often occurs in practice?

What was said above might be a bit incorrect; I think when the system experiences pressure buildup, it means that the load is already below 20%. At that point, it’s necessary to switch to override control in order to relieve pressure through the return valve and achieve pressure balance. And when the load is above 20%, the cylinder can be regarded as a passage at this time. A load of less than 20% should not be an operating condition.

The device I’m using features stepless adjustment of air volume; by controlling the duration for which the air valve is open or closed, it is possible to adjust the compressor load between 0% and 100% arbitrarily. Typically, compressors only have several load levels such as 0/25/50/75/100. As for the back-pressure issue you mentioned, I can’t understand it; if back-pressure occurs, how can a reciprocating compressor still be used? I work in diesel hydrogenation units, so it’s inevitable that my knowledge is limited.

From a process perspective, downstream pressure buildup as a fault condition must certainly be taken into account. If using a stepless air volume control system means that the return line may be closed, the system controls the air volume by adjusting the load, focusing only on the condition of the compressor itself. If the cylinder can be considered a passage, then there’s no problem, but in this case, how does the exhaust valve open to create a passage? Also, I would like to ask why a variable-frequency motor was not chosen in favor of an air volume control system, given that variable-frequency motors offer a much greater price advantage. I hope you can offer your guidance; thank you!

This post was last edited by A pot of fragrant tea on 2016-1-18 21:17. Watching this video will be helpful to you: http://wenku.baidu.com/view/e85061127cd184254b353566.html?from=search

I’ve learned from it – the explanation of the principle behind dynamically variable clearance chambers is excellent, and there are also many photos from the field. Thank you so much! But there are indeed some issues with the data provided. In the data from the first table, the energy consumption is already less than the useful energy required for compressing the corresponding gas; this is basically impossible. An objective evaluation shows that, compared to the control of intake valve opening and closing, its advantage lies in the lower precision requirements for the equipment, with potentially better reliability. Relative drawback 1/ Modification: Modifying the equipment is more complicated, and it’s still not possible to avoid the need for hydraulic systems (is there no option using electrical signals!? ), changes are also needed on-site. 2/ The clearance chamber means that the feedback speed of the moving components might be slower; it’s essentially equivalent to increasing the volume of the cylinder block as well as adding counter-pistons, and the energy consumption associated with this is likely to be significant. If relevant data is available, it can be discussed together. 3/ The control range is relatively small. Just my personal opinion; feel free to refute it, offer criticism whenever possible, and let’s improve together. Thank you so much! At the same time, I hope some friends can provide information on the application of variable-frequency motors in reciprocating machines. Let’s discuss it together

I also received the above information from the internet; the manufacturer states that only when the shaft power is high and the backflow is significant can the energy-saving effects be considered satisfactory. If you have any objections, feel free to contact the manufacturer.

Does that brother have any photos of the HydroCOM hydraulic oil station? I’d like to see what level of modification is required as a reference

It’s in the HydroCOM system training documents; you can take a look.