Issues regarding turbine vacuum
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This post was last edited by Junior worker on 2019-3-13 at 10:00. Hangzhou Automobile: there is one main exhaust pump (on the east side), one backup exhaust pump (on the west side), and one auxiliary exhaust pump. The current exhaust pressure of the turbine is -64 kPa, which is too high; therefore, two sets of exhaust pumps are to be used to maintain a vacuum level. When the backup main exhaust pump (on the west side) was activated, the vacuum level started to rise slowly, so it was turned off again. Experts, what could be the reason for the increase in vacuum level when the main exhaust pump on the west side was in use? ? ? Please give some advice, one or two things,,,
This can only be determined if you provide a detailed description of the structural types of the main, backup, and auxiliary vacuum pumping equipment.
Steam ejector; currently, the computer doesn’t allow images to be uploaded,,,
The last edit to this post was made by symc on 2019-3-14 at 21:12. If all are suction pumps and the models of these pumps are the same, then generally, the following reasons can cause an increase in the vacuum level in the auxiliary pumping system: 1. The head and flow rate of the water pump are not sufficient to match the performance of the main pumping pump； 2. Poor sealing of the valve at the connection between the main exhaust pump and the condenser – This can be checked by closing the main exhaust pump valve while leaving the exhaust pump itself open; if the auxiliary exhaust pump is able to meet the vacuum requirements under these conditions, then the problem lies in the poor sealing of the valve at the main exhaust pump ； 3. The auxiliary extraction nozzle needs to be replaced... I just realized that I thought it referred to water jetting... :L For steam jetting, it’s the three points mentioned above; the first one should be changed to checking the steam pressure and the inter-stage condenser
Has the main pump been overhauled? Evaluate the exhaust performance. The main reason for the low vacuum in the condenser is poor cooling efficiency; cleaning the condenser and improving water quality are necessary solutions.
Based on the problem you described, it is initially suspected that the steam pressure, flow rate, or superheat level is insufficient. Please check whether the steam pressure decreases when the backup extractor is turned on. Our factory encountered this problem before: all the primary, secondary, and auxiliary pumps were connected through a single main pipe. As the number of users increased, the flow rate became insufficient, so it was necessary to expand the main pipe. The poor vacuum is also caused by water in the steam (low-pressure steam). Normally, one set is sufficient for operation; however, there are many factors to consider: 1. Is the second extraction working properly? ； 2. Is the liquid level in the intermediate condenser proper and is drainage unobstructed? 3. Is the system poorly sealed? 4. Cooling efficiency of the surface cooler. 5. Is the sealed steam of satisfactory quality, and is the pressure sufficient? Wait, if your coil coolers are also responsible for recovering various condensates, then a more thorough inspection is even necessary.
If yours is a fully condensing system, then the exhaust pressure in your system is too high… The efficiency is quite low… It’s necessary to conduct a thorough inspection, especially regarding the tightness and cleanliness of the condenser. Additionally, using steam jets for vacuum creation is quite wasteful of steam, as the thermal efficiency of this method is much lower than that of a turbine. Moreover, in most cases, using two steam jet systems simultaneously yields essentially the same results as using just one system; it’s only when the vacuum level achieved by a single steam jet system is not sufficient that using two systems becomes useful
It’s because the vacuum level was too high – at -64 kPa – when one set of exhaust pumps was in use; therefore, it was intended to use the backup exhaust pumps to maintain the vacuum level. However, the other set of pumps cannot be used at the moment. When that other set was activated, the vacuum level dropped temporarily, but then it started to rise again, so those pumps were turned off. It was also observed that the vacuum gauge on the secondary exhaust pumps indicated a negative pressure reading. How can there be a negative pressure reading if those pumps aren’t in use? Both the steam valve and the air valve are in the closed state,,,,
Were the valves not mixed up when switching?
The valve was definitely not used incorrectly during the switchover
The steam pressure of the extractor is 1.2 MPA, and it remains relatively stable; basically no liquid is discharged from the drain lines. Question: Can I modify the existing 3.8 MPA steam pipeline to connect an additional line that supplies steam to the extractor? ? ? Answer: 1. When the pressure at the first stage is -75 kPa, the pressure at the second stage is -80 kPa. 2. The drainage from the intermediate condenser is unobstructed, and the temperature of the pipelines can be felt to determine the flow rate. 3. It’s difficult to assess the system’s sealing performance; some areas are hard to inspect. How do you usually check vacuum systems? 4. The cooling effect of the surface cooler was poor before; it was cleaned during maintenance a couple of days ago, and the vacuum level improved somewhat, but it’s still not ideal. Now there is suspicion that the tubes might be blocked (the temperature of the condensate in the heat well has risen, as has the temperature of the exhaust cylinder). 5. The sealing steam is of satisfactory quality; it comes from the main steam. The pressure cannot be measured directly, so we judge its level based on the steam coming out of the shaft seal signal pipes