A Record of Winter Night Shifts 1
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After the first snowfall last night, the temperature dropped; from 1:30 a.m. to 6:30 a.m., I dealt with 3 frozen surfaces, taking a 30-minute break in between. The first gauge was affected by steam generation in the air pocket; we used antifreeze to flush it. Upon arrival at the site, we found that both the positive and negative pressure sides were frozen, which was quite troublesome. We had to use steam to clear the pressure relief pipes, but the effect of using insulation material was reduced after that. When we tried flushing again with antifreeze, one side became unblocked. This gauge was located on the 14th floor, where the wind was very strong; fortunately, I didn’t feel cold at that time. We used steam from that side to discharge the fluid through the vent valve, gradually thawing out the frozen side as well. After that, we flushed the area with antifreeze to replace the fluid, and the gauge started working properly. It was 3:30 when this happened; at 4 o’clock, another gauge stopped working. Thankfully, one side was still functional, and we managed to unblock it using the same method. However, when we flushed it with antifreeze, the pressure didn’t drop, suggesting there might be a blockage. It was a tough situation. Later, after testing with the vent valve, we discovered that the industrial pressure gauge was broken and giving false readings. This led me to check the antifreeze pump room, thinking the pump wasn’t functioning properly. That gauge was also located at a height of over 20 meters, so I had to make an extra trip there. Once it was fixed, it worked normally. It was 5:40 when this happened. At 6 o’clock, we dealt with the third gauge, finding that there was a problem with its insulation; the heating system was working fine. Since there was no way to provide proper insulation, we used gas to thaw it temporarily. We would redo the insulation work during the day. By then it was almost 7 o’clock. The previous night, one of the control valve gaskets had leaked, and we also had to flush one of the flow meters. I only managed to sleep a little over 2 hours that night. Currently, the lowest temperature at night is around minus 11 degrees. There’s so much work to do; it seems like this winter will be a busy one. I’m recording all this so that I can share it with my colleagues who are working hard on maintaining instruments during the winter months. For me, it’s a great spiritual pleasure.
Bro, it’s tough working all night; winter is the worst season for working with instruments. However, knowing full well that temperatures are low in winter and this can cause instruments to freeze, why not carry out insulation and heating measures earlier? This would ensure smooth production, prevent instrument damage, and also reduce the workload on those instruments.
Antifreeze is particularly vulnerable to dilution by water in the fluid it’s used in. In our factory, during the very cold winters, freezing would occur at the valves located near the pressure sensing tubes. At first, we suspected various things such as the correct mixture of components in the antifreeze, insufficient amounts added, or poor insulation; but all these possibilities were ruled out one by one. Eventually, we changed our approach and considered the process itself – we realized that the fluid contained a small amount of water. As a result, during maintenance work, we installed heating elements along the section of pipe downstream from those valves, and since then there have been no more problems.
The main reason is that the pressure guide tube comes into contact with the medium, and there are various reasons for this. The most significant ones include leakage from the antifreeze valve, high pressure of the medium, and malfunctioning check valves. When ethylene glycol is mixed with water in the correct proportions, it won’t freeze; however, when the pressure guide tube no longer contains pure antifreeze, the mixture of the medium, rust, and antifreeze makes it prone to freezing, that is, its freezing point increases
All the necessary work is carried out before winter arrives. However, since the equipment is quite old, we usually replace the antifreeze before the temperature drops. Yet there are still issues with some pressure pipes and check valves, and in some cases, the antifreeze valves do not close properly
Yes, as you said, by working carefully to identify the root causes, the underlying problems can be solved. I have considerable experience with heating systems, antifreeze, and pressure guiding pipes; I deal with these issues every winter. To address the problem at its source, it’s necessary to install proper heating systems, replace certain pressure guiding pipes, as well as antifreeze valves and check valves. We use hot water for heating, but when temperatures drop below minus 20 degrees, the circulation of hot water becomes poor. Most of the heating pipes are made of carbon steel, and scale builds up inside them. I once spent 3 months carrying out maintenance work in a refinery in the north; there they used 10 kilograms of steam, and both the heating pipes and pressure guiding pipes were new (it was a newly built refinery). The surfaces didn’t freeze over during those 3 months, though there were a few instances of vaporization. Our older factories can’t compete with such facilities in this regard – we can only carry out minor repairs and hold out through the coldest two months or so. This happens every year, sigh
Hot water heating is a real hassle in the Northeast – the pressure is insufficient and the water temperature isn’t high; if the insulation isn’t good enough, the heating pipes freeze over even in deep winter. Insulation is particularly important for instrument pressure pipes in winter. Our factory made great efforts to carry out improvements because, for two consecutive years, equipment shutdowns occurred due to freezing of the instruments; bonuses were deducted from everyone, from technicians to managers, which prompted higher management to pay attention and invest heavily in repairs. In the old factory, the insulation had been damaged, and the insulating material had long lost its insulating properties; years of water infiltration had caused it to harden. When the insulation is redone, each piece of work must be signed off by a technician, and the result is excellent – problems that occur due to dry conditions throughout the night in winter no longer happen. It’s not the case that no money was spent; if any was spent, then it simply wasn’t spent properly
It is recommended to be a leader, so there’s no need to go to the site
Indeed, that’s exactly what you mean