Mechanical relief of liquid hydrocarbon pumps
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This post was last edited by Black gold on 2011-11-28 at 16:50. Our factory has over twenty liquid hydrocarbon pumps, and during winter, when the standby pumps are rotated, seal leaks often occur; sometimes these leaks are severe, resulting in the destruction of the seals； Some people use steam to warm it up first, then operate it a few times to create a liquid film on the pump seal, and that solves the problem. In fact, it’s not correct to use steam directly on the pump, as uneven heating of the components can cause them to crack; I’ve encountered this situation before, where both the water jacket and the bearing housing cracked. When this happens, the only option is to use steam for heating, otherwise the leakage will be severe and difficult to control. Sometimes the inlet and outlet valves get stuck, which leads to pressure release, and this can help a bit. But these are not permanent solutions. I would like to ask those with more experience for some advice on preventive measures against freezing in hydrocarbon pumps during winter, as well as ways to deal with the tricky issue of pump seal leakage Thank you here!
Can’t we use hot water? Why do we have to use steam? Alternatively, you can just close the inlet valve of the pump to release the hydrocarbons from within the pump chamber
I’ve tried using hot water, as mentioned above; the machine’s seal leaks severely, with hydrocarbons leaking out and spraying around the mesh. Can hot water prevent this? Your second method is also good – I’ve tried it too. If the leakage is severe, that’s the only option left! Thank you!
Steam can be used; for liquefied gas, naphtha, and other light hydrocarbons here, in winter we tie rubber bands around the impeller, and using a little steam has worked well for four or five years now (I’m in North China)
Actually, the simplest method is also the most straightforward one: disassemble the pump.
Can electric heating be used, or can a small amount of reflux be taken from the pump outlet to keep it in a heated state?
This kind of issue occurs with your backup pump; injecting some backflow should be able to resolve it. Adding heat tracing will solve the problem once and for all, ensuring it doesn’t happen again!
The best approach is to add a bypass line at the pump’s outlet, one that goes straight past the pump’s check valve and gate valve. Similar to a hot oil pump, a preheating line should be installed at the outlet so that the fluid inside the pump remains in motion and at a certain temperature at all times. Only in this way can the pump’s seals remain in a expanded state, thus ensuring proper sealing and solving the problem of leakage in the shaft seals of standby pumps.
It’s better to add a pre-heating line; it’s more durable.
When stopping the pump, drain all the fluid from it. Keep the sealing water flowing continuously to prevent the fluid from crystallizing and damaging the seal. Also, turn the pump manually at the end of each shift; don’t be afraid of the hassle – it will definitely work.
Our workshop has also encountered similar situations; we can add a bypass valve in front of and behind the check valve, slightly open the outlet valve, fully open the inlet valve, and use the bypass valve to control the backflow volume. This approach works well – we have been using it for 2 years with no problems, and it doesn’t interfere with production while the machine is in operation. In my opinion, strengthening the turntable is not an effective solution, as the seal can easily be damaged by ice shards.
Just add a wire connected to the hot wire, just like in a hot oil pump! As there is a fluid flowing inside the pump, its temperature won’t drop too low; generally, the situation you described does not occur. I’ve seen some devices that use this method! They say the effect is very good!
Let’s install an electric heating system. :)
I’m not sure if your pumps are stored together; if they are, you can build a steel structure roof over them. If they are scattered, consider other suggestions. Hehe
Creating a return flow through a pipe leading from the pump’s outlet can increase the flow of the medium and prevent freezing blockages; combined with appropriate insulation measures, this approach can effectively counter the damage caused by low winter temperatures to the mechanical seal.
I work in the north, and our pumps are not installed outdoors like those in refineries in the south; they are all placed inside pump rooms. Therefore, the problem mentioned by the poster does not occur in winter