Compressor fifth-stage overpressure
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We have an old machine with seven-stage compression (no air extraction between stages 3, 4, 5, and 6). Due to changes in operating conditions, the designed pressure at stage 5 is 6 MPa, but the actual pressure during operation is 7 MPa, which is highly unsafe. Do anyone have any ways to deal with this? Could it be solved by increasing the clearance at levels 3 and 4?
The five-stage overpressure in your compressor is likely caused by an increase in the outlet back pressure; the only solution is to reduce the outlet back pressure – there is no better way.
Increasing the diameter of the sixth cylinder can solve the problem, but we think it would be a bit complicated to do so.
What does the change in operating conditions referred to by the poster mean? If there is no inter-stage pumping, why does only the five-way pressure increase? Has the pressure at stage six increased? I think it’s better to look for the reason from a technical perspective. Make sure to thoroughly check whether the level 6 valve is damaged, whether the five-output pipeline is blocked, and how well the cooling water in stage 5 is functioning.
Are the pressures at level 6 and level 7 normal? Didn’t the pressure increase before level 5?
The most likely possibility is that the exhaust valve at level 5 is leaking or blocked, or that the intake valve at level 6 is leaking. Since there are multiple valve plates, the leakage is likely to be minimal, so there is not much change in flow rate!
The change in operating conditions means that instead of using the original method of sending the gas to a wet decarburization unit for treatment, it is now being processed through a two-stage conversion and series decarburization process. Many used units (from models 73 and 92) were purchased in haste; since there was little understanding of the machine’s original operating parameters, it was only after use that it became apparent that something was wrong. The air valve is fine; the pressure in the sixth and seventh stage delivery systems is also normal. This post was last edited by *aoye613 on 2009-2-10 08:25]
If the system pressure at the secondary outlet is high, it will also affect the outlet at position five. It can help reduce the pressure that arises in various places, which is beneficial for alleviating the issues that occur in five different areas.
Our compressor originally experienced overpressure in stage 5; after enlarging the cylinder diameter of stage 6, this overpressure issue in stage 5 was eliminated.
We have encountered this phenomenon as well: it involved two old Hongqi brand compressors. Before the system modification, there were not many problems, but after the modification, running both compressors at the same time caused a five-stage overpressure issue. The analysis indicated that this was due to an imbalance in suction and discharge volume.