The design of the spring hanger currently mostly adopts a hot zero hoisting scheme, that is, when the pipeline is in a hot state, the load of the spring hanger is equal to the working load assigned to the hanger point.
During the work of the spring hanger, there is a certain load change; the supporting point with large thermal displacement requires multiple springs in series, and the number of series is limited. Therefore, the spring hanger will not be able to meet the needs for strictly controlled load changes and large thermal displacements. But it has the advantage of simple structure, so it is still widely used. During the installation and use of the spring hanger, the following aspects should be paid attention to.
(1) According to the installation load provided by the user, the manufacturer uses the upper and lower positioning blocks to fix the indicator plate of the spring hanger at the position corresponding to the installation load, so that the spring hanger is temporarily in a rigid state.
(2) When the pipeline starts to run, first check whether the positioning block is closed and removed, and then check whether the indicator board is jammed during the displacement process from the installation load to the working load.
(3) After the pipeline is put into normal operation, check whether the displacement of the spring hanger under working load is consistent with the design. After the pipeline stops running, check whether the indicator board is reset to the position where the load is installed.
(4) After the pipeline is cleaned and water pressure tested, remove the upper and lower positioning blocks before putting the pipeline into use.
In the spring hanger, the load of the hanger is vertically directly balanced with the spring force, and the spring force is the product of the spring stiffness and the compression value. When the fulcrum point produces a vertical thermal displacement, the spring compression value also changes, and the load of the support frame also changes. If a suitable spring can be selected, the load change of the support frame will be limited to a certain allowable range. Inside, there will be no large change in load or no effort like a rigid hanger.