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Experts teach you how to choose a better steam trap

ISRI said that with the continuous development of high molecular materials and plastic products in Huddersfield and the performance of steam traps in Grangemouth (England) industrial plant, a formal announcement will be released in July for 7 years of monitoring and testing, Level I on the basis of the monitoring and experiment on the performance of the steam trap and the loss of fresh steam carried out by the laboratories of two manufacturers, the Royal chemical industry company of the United Kingdom finally revised the contents on the selection of steam trap in its engineering design guidance

the old model selection standard has many shortcomings, the most obvious is that it does not mention the type of equipment to be drained and the drainage method. The selected drain valve often does not match the actual load. In particular, the thermal power disc steam trap (the basis of the old model selection standard) was mistakenly regarded as a universal steam trap by people, especially those in the No. 1 production workshop

as early as 1980, Grangemouth factory began to use the performance of steam traps because engineering maintenance personnel complained that the service life of steam main drain valves was too short. Such products are often guaranteed to be monitored. Two years later, the Huddersfield factory did the same monitoring

during the monitoring, the first step is to investigate the steam traps, understand the types of existing steam traps, and check the load during model selection. At the same time, relevant tests were also carried out. The preliminary results were startling. The inspection results of 415 steam traps in a workshop show that 19% of the steam traps are effective, and 63% of the load models are mismatched

the inspection of 132 steam traps in the main steam pipe shows that 42% of the traps have been effective. The inspection of the service life of the steam trap was started in 1980 and has continued to this day. Table lists the average service life of various traps

in order to test the energy-saving benefits of various traps, people have tested the fresh steam loss of the traps being used in the laboratories of two manufacturers. The test is carried out in the laboratory, i.e. 20 ℃, still air. The test did not detect the heat loss of the steam trap valve body. During the test, the condensate load is the common kg/h (LB/h). The test results are summarized in the table. The most interesting point shown in these two tables is that as a general-purpose and most widely used thermal disc type drain valve, its energy-saving effect is the worst, and its service life is very short compared with the inverted bucket drain valve

when the heat demand is not high, replacing the thermal power disc drain valve with the thermal static drain valve will improve the energy-saving effect and ensure the service life

these experiments also reveal that mechanical traps (i.e. inverted bucket and floating ball traps) can ensure that the steam does not contain condensate no matter the condensate load is large or small, while the thermal static traps are easy to accumulate condensate when the load increases

in addition, the action of bimetallic drain valve is easy to be unstable

the revised new guidance includes the selection table of steam trap

current model selection recommendations:

inverted bucket drain valve:

as the first choice for all process loads and steam main line drain valves, that is, all occasions requiring steam drainage

floating ball thermostatic drain valve:

used for process drainage, especially in the application occasions with control load less than 3.5kg (50psig) or the occasions with high air content and problems in installing inverted bucket drain valve

balance pressure drain valve:

used as unimportant heat tracing or heating system

bimetallic sheet thermostatic steam trap:

used for low temperature or frost proof conditions of heat tracing pipeline or heating system. This type of steam trap can maximize the use of sensible heat in condensate or prevent product overheating. The valve body is all stainless steel

thermal power disc steam trap:

as long as its performance is proved to be good by previous experience, it can be used as a substitute for inverted bucket steam trap, which can be used on steam main pipe and heat tracing pipe with pressure below 17 kg, or as a product for higher steam pressure. It is not recommended because of its low energy efficiency and short service life

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