Local freezer and manufacturing method

Abstract

The invention relates to a local freezer which is used in city underground engineering freezing and can effectively reduce losses of refrigeration capacity at a non-freezing section and an implementation method thereof. The local freezer comprises a liquid inlet pipe, a liquid return pipe and a freezing pipe. The freezing pipe is mainly composed of a non-freezing section freezing pipe body, a freezing section freezing pipe body and a conical blade angle part. The liquid inlet pipe and the liquid return pipe are installed inside the freezing pipe, and the upper end of the liquid inlet pipe andthe upper end of the liquid return pipe extend out of the freezing pipe. The local freezer is further provided with a thermal insulation material, an insulated joint, a transition casing pipe, a trepanning partition plate and a heat preservation cotton. The losses of refrigeration capacity (heat conduction, heat convection and thermal radiation) at the non-freezing section can be reduced by takingthe measures of mounting the insulated joint on the freezing pipe, filling the thermal insulation material into the freezing pipe, laying the heat preservation cotton and the like, the cooling capacity utilization rate of the local freezer is increased, and it is of great significance indistribution power of a refrigerating machine, freezing closure time and soil mass excavation at the non-freezing section. The structural style of the freezing pipe is simple, field splicing and mounting can be facilitated and the local freezer and the manufacturing method can be widely applied to freezing engineering.

Description

technical field [0001] The invention relates to the field of partial freezing in the freezing technology of urban underground engineering, in particular to a partial freezer and a manufacturing method. Background technique [0002] With the development of urban modernization, people's demand for space is gradually increasing, so it is necessary to build underground railways, which is also an effective measure to alleviate traffic congestion. [0003] Taking the Beijing area as an example, it can be seen from the characteristics of the vertical distribution of strata in the Beijing area that as the excavation depth increases, pebbles and gravels gradually increase, and the groundwater content gradually increases. Traditional support methods such as underground diaphragm walls and water-stop drainage Problems such as poor applicability, increased cost, and inability to meet construction requirements have successively appeared in piles and well point precipitation, etc., making...

AI Technical Summary

Problems solved by technology

When the "pelvic floor" freezes, it is necessary to strictly control the thickness of the "pelvic floor" by using local freezing technology, which not only needs to avoid the problem of insufficient bearing capacity caused by the thickness of the "pelvic floor" being too thin, but also needs to avoid the problem of excessive thickness of the "pelvic floor". Large construction difficulties and uncontrollable later melt settlement displacement

[0005] At present, in the local freezing project, in order to reduce the cooling capacity loss of the non-freezing section, the main methods are to change the distance between the liquid inlet and return pipes, install partitions in the non-freezing section, vacuumize the non-freezing section, and keep the non-freezing section warm. Several structures are mostly used in local freezing projects in a single form, without considering the loss of cooling capacity in various situations, resulting in the actual distribution power of the freezing station in the actual local freezing project far exceeding the calculated value, and the non-frozen soil area eventually evolves into Permafrost areas increase construction costs and duration

In addition, in the current partial freezer structure, most of the structural forms block the radial heat conduction of the non-frozen section, and the cooling loss caused by the axial heat conduction from the frozen section to the non-freezing section and the heat radiation and heat convection of the non-freezing section There are few reports, and these three cold transfer methods occupy a certain proportion in the non-freezing section

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