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Spring hangers – comprehensive service
Selection of hangers at the design stage
BTHU Thermex s.c. prides itself on highly qualified engineering staff. Knowledge, experience and broadly understood knowledge of the topic of hangers in the energy sector allowed us to introduce a comprehensive service, which is:

– selection of appropriate hangers at the design stage of suspended elements in power plants, cogeneration plants, waste incineration plants, etc.,

– design of a new spring assemblies based on design data of the loads for the designated attachment points of suspended mechanical systems (power boilers and its internal pressure components, pressure pipelines),

– design of a new spring assemblies and determination of the load value for individual hangers of the existing suspended mechanical systems based on the actual load measurements occurring in a given rod (in the absence of available technical documentation),

– delivery, assembly, measurement and adjustment of loads in new suspensions produced by BTHU Thermex s.c.,

Design and execution of the spring assemblies
Many years of experience gained during the measurement and load adjustment of the boiler hangers and other statically indeterminate systems occurring in the industry makes us one of the few, and possibly the only company on the market that offers such a service. Our adjustment works have repeatedly confirmed a significant difference between the design loads and their actual values, which confirms the validity of hydraulic measurements to determine the correct values of the reduced loads to which the hangers should be adjusted. This means that the design value of the load, which is given on the rating plate of the hangers supplied and installed on the object, is insufficient and requires correction based on measurements and load adjustment in all suspensions of a individual mechanical system.

Fig. 1. Examples of spring assemblies.

New spring units (fig. 1) are pre-compressed with the nominal load which is given from the documentation or pre-measurements and blocked with the safety pins (fig. 2).

Fig. 2. Testing a set of springs on a universal testing machine, including performance of the force-displacement relationship.
Replacement of spring suspensions on site.

Replacing hangers on the object is being executed consecutively on each hanger. After blocking the rod and unscrewing the main nut, the old unit is disassembled. The new spring assembly is installed immediately, along with the setting of the appropriate load (Fig. 3). The replacement is carried out with the use of a hydraulic system, which allows for precise adjustment of the load in the replaced hanger and eliminates the risk of damaging the rod thread when unscrewing the main nut under load. There is no need to block or additionally suspend the structure on which the work is carried out, which increases the safety of the entire procedure.
Fig. 3. THERMEX spring assemblies supporting the waterwalls of the BFB-110 boiler combustion chamber.