Selection and optimisation of pressure vessel strength testing

The primary purpose of periodic inspection of a pressure vessel is to ensure safe operation throughout its entire service life – ensuring safety during operation. To achieve this, both the accredited body and the user must cooperate at the highest possible level of trust. The accredited inspection body offers the user comprehensive execution of prescribed types of periodic inspections of the pressure vessel. They found that strength tests could be further improved and thus optimised. In order to carry out strength tests with even higher quality, they desire ** electronic data recording capabilities** via pressure gauges.

Problem

The primary purpose of periodic inspection of a pressure vessel is to ensure safe operation throughout its entire service life – ensuring safety during operation. To achieve this, both the accredited body and the user must cooperate at the highest possible level of trust. The owner or user is fully responsible for ensuring that the pressure vessel operates normally.

Solution and method

The accredited inspection body offers the user comprehensive execution of prescribed types of periodic inspections of the pressure vessel. With professional assistance from the accredited body, the user ensures technically correct and safe operation of the pressure vessel. The diploma thesis described different types of strength tests. ** They identified the advantages and disadvantages** of each strength test.

They carried out only one type of strength test, namely pneumatic. The pneumatic test was carried out on their existing equipment, which is located at their facility in Črnuče. The work had to be adapted to the requirements set by the user of their pressure vessel. In doing so, they were not allowed to interrupt the energy supply from the pressure vessel.

The vessel is filled with compressed nitrogen, which serves as system protection when filling the cylinder with acetylene. They opted for this type of strength test due to several factors such as: The execution of the process itself is fairly quick and low-cost. Since the pressure vessel was not contaminated with moisture, it did not need to be dried after the test and was immediately ready for use.

With this test, they demonstrated the advantages of the execution itself.

Results

They found that strength tests could be further improved and thus optimised. In order to carry out strength tests with even higher quality, they desire electronic data recording capabilities via pressure gauges. Currently, data is only recorded manually, based on visual verification.

In the case of electronic data recording, they would have ongoing evidence for easier preparation of the final certificate of completed work. In the future, they are also considering introducing pressure vessel inspections using acoustic emission. The acquisition of such equipment is still too expensive for now, and their market is too small with strong competition.

They are also limited by knowledge, as execution with acoustic emission is fairly demanding. Above all, the work requires knowledge for evaluating results. Carrying out a strength test with acoustic emission certainly has many advantages, but also disadvantages.

The advantage lies primarily in the straightforward execution of the pressure vessel inspection itself. If they want to master and introduce new technology, additional training is required, but there is too little of it in their field in Slovenia, so they attend additional training mainly abroad. Training for work in their field is very important, as it enables them to acquire new knowledge or use new technologies in carrying out strength tests of pressure vessels.

They believe that only through continuous training can they achieve results that do not affect the safe execution of strength tests and will primarily assist them in further work. So far, they are satisfied because they are achieving the goals they set, but goals must be set realistically. Their main principle is not to deviate from legislation and regulations and to treat all clients equally, whether in the pharmaceutical field, food sector or other manufacturing industries.

The actual execution of the strength test differs according to individual requirements that apply to users of pressure vessels. It is very important not to endanger the safety of human and animal health and consequently not to endanger the impact on the environment in which they operate. Only a developed system of pressure vessel preparation for inspection and execution of the strength test enable efficient use of time and energy, environmentally acceptable factors, and consequently cost reduction and increased safety in carrying out the strength test of the pressure vessel.

Only quality and constant supervision of pressure vessels ensure safe work during the use of vessels at customers' premises.