How to prevent freezing of the circulating fluid pipeline for “slurry-type shield pumps” in winter
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Dear experts, I would like to ask for your advice. As winter approaches, several \"slurry-type shield pumps\" are in operation here. Since they operate on a one-in-one-backup basis and need to be switched over daily, both the inlet and outlet main pipes of the backup pump are equipped with heating systems. The pumps themselves have circulation fluid pipelines (not cooling water pipelines), and the fluid within these pipelines freezes very easily during winter (within 2–3 hours). These circulation fluid pipelines are quite thin, and the fluid inside them is used primarily to lubricate the bearings and cool the motors; it is essential that the flow in these pipelines never stops, otherwise the bearings can be easily damaged. Since the medium in the circulating fluid pipeline does not come into contact with the medium at the turbine’s inlet and outlet, and circulation is carried out independently by a secondary impeller, it is not easy to empty this system. Is there any good way to ensure that the unit remains in good condition during winter? The current methods are as follows: 1. Before putting the pump into use, steam is used to purge the external circulation fluid pipelines, which is time-consuming and labor-intensive and creates a poor working environment; 2. When some pumps are in standby mode, steam is used for the internal circulation water pipelines, and the steam is turned off before starting up the circulation water. I would like to ask if there are any other economical, safe, and efficient ways to keep the pumps in good standby condition.
The circulating fluid pipeline is external, located above the pump body.
“The pump itself has a circulating fluid pipeline (not a circulating cooling water pipeline); the fluid in this pipeline freezes very easily in winter (within 2-3 hours). This circulating fluid pipeline is quite thin, and the liquid contained within it is used primarily to lubricate the bearings and cool the motor. It is essential that this flow of fluid never stop, otherwise the bearings can be easily damaged. ”What is the medium in this circulating liquid, and why was a medium that freezes easily chosen? Can’t an antifreeze medium (such as an ethylene glycol solution) be used?
The details of the layout of the on-site equipment and facilities are unclear; it would be best to send a video. If there is steam, should one consider installing insulated rooms or boxes? Is it feasible to use steam for insulation? Also, the relevant pipelines are heated using electric heat tracing or steam tracing. For reference.
Use a household car washing high-pressure hose as the steam tracing pipe, wrap it around the areas that need tracing. Locate the steam supply point within the device, select a low-pressure steam pipe, install a 20mm tee; fit 20mm threaded fittings on each of the two ports and attach 20mm internal thread ball valves to them. Install 20mm to 10mm copper adapters on the ball valves, and then connect the high-pressure hose to it. Steam can also be led to near the pump using 20-gauge galvanized pipes, and then connected to high-pressure hose pipes.
If there is steam available, it can be used as a steam tracing tube; if not, an electric tracing tape can be used for tracing
It’s not easy to make changes casually. The medium in the circulation fluid pipeline is the same as that in the main pipeline. To prevent damage to the mechanical seal, the fluids in the circulation fluid pipeline and the main pipeline are kept separate, so it’s not possible to change them easily. . .
There are many pumps and the space is large; insulation conditions are not available for now. Thank you