At SERTO AG in Frauenfeld, a whole team of technicians, designers and product managers work on the maintenance and further development of the product ranges. This includes monitoring the product dimensions as well as checking the technical specifications. We carry out relevant tests in our own test laboratory for these regular product range checks, for our own product developments and also on customer request. We would like to present a selection of our testing options to you here.
SERTO has good connections to independent institutes and higher education institutions for important tests and clarifications which we cannot carry out at our premises. The experts and experts assess, among other things, long-term developments of materials, regularly check the efficiency of our cleaning system and support us in new and further developments.
The most important tests at SERTO are as follows:
The helium leak probe is used to test out our metallic tube connections for their tightness, both for all material and supplier changes and for new designs, as well as on a regular basis for current orders. The union to be tested is assembled on a tube closed off on one side and then tested in a vacuum chamber. We have two different sizes of testing chamber available, optimally designed to cater for our range of unions. The test medium is helium, which is distributed quickly and correctly into the union at a pressure of 10 bar. The test device is able to measure leak rates between 10-4 and 10-9 mbar l/s.
DIN xy defines how the bending strength is tested. The load and number of load changes (107) are preset, but the amplitude and frequency are variable. Eight test units are filled with oil at 1.3 times the rated pressure of the union. Each inspection body is controlled separately. The top union is firmly clamped, with the lower one moving around on a rotary plate. A PC controls and monitors the test run, and a protocol documents the results. The test is regarded as having been passed according to DIN 3859-3 if all six test units have successfully passed the test.
The flow rate behaviour is measured here for valves, couplings or complete lines using all kinds of different settings. For this particular test, we use water as it can be heated, is incompressible and available at all times. What do the SERTO technicians assess? Noises and pressure differences. The inner form of the test units and the transitions in the media duct may give rise to turbulence, which causes noise emissions. The structure and design of the valve components and the fit and design of the spindles determine the resistance and loss in pressure of the media flow. The volumetric flow rate, input pressure and temperature may be varied for this test.
SERTO has worked in collaboration with FH Brugg to develop and build a vibration tester. We use this in particular to test out unions for their tightness when subject to vibrations for applications in transport. The swivelling clamping device enables a load to be transmitted in a vertical and horizontal direction. The amplitudes move within the millimetre range (0 to 2.5 mm), and the frequency can be adjusted up to max. 50 Hz. The test units are subjected to this test for a minimum of one hour. They are examined for their tight fit both before and after, and need to pass the SERTO tightness test in cases where industrial gas tightness is required.
In this particular test stand, we test out the pressure resistance of unions in accordance with the applicable ISO standard. There are different test options available: By using the bubble test, the test unit subjected to pressure is tested for its tightness in a basin filled with water. The test unit is connected to an air/gas circuit, the attached (internal) pressure may be adjusted up to 35 bar, or up to 550 bar if using nitrogen. Or we can test out a tube section with unions attached on both sides to failure up to max. 4,000 bar until the system is no longer sealed, the tube bursts or slips out of the union. Or we can test them using water pressure pulses of 20ms up to max. 240 bar.
In our catalogue, we have specified a safety factor of 4 for our pressure information, which means that we test out the pressure resistance of our range on a regular basis, subject to 4 times the rated pressure.
In our climatic test cabinet, we simulate realistic operational and environmental conditions and test out the tightness of products in all kinds of different materials. By doing so, we are able to assess their weather resistance on the one hand, as well as test the impact of (artificially caused) weathering processes, such as for plastics (brittleness) on the other hand. We expose our metallic items to temperature cycles between -70° and +180°C and statically test their tightness using water glycol and nitrogen directly in the climatic test cabinet. The tests for assessing the tightness of material combinations in the event of temperature fluctuations are of particular importance to us.
The extract test stand is particularly used by our technicians for compression ferrule developments and material comparisons. A mounted screw-in fitting is therefore strained in an axial direction, the tube and thread are fixed in place, and the resistance and/or holding force of the compression ferrule on the tube/hose is assessed.
This load test determines the tightness of valves following a defined number of operating cycles. Firstly, the 500th to 40,000th opening and closing of the valve is simulated. Tightness tests, whereby the wear and tear of the sealing element is assessed, are carried out before and at every 5,000 cycles.
Subject to optional compressed air up to 10 bar, couplings are coupled and decoupled; before the start of the test, and periodically during the course of the test, we will test out the tightness under water with air for plastic couplings, or with helium for metallic couplings, until the test unit fails.
This involves the goods issue inspection of our Jacoflon hoses. The customer is responsible for defining the number of test units and the test pressure (0.5 - 2x operating pressure). We carry out tests under water with nitrogen, the observation time is 1-5 minutes depending on the hose type.
