Multiple Pressure Test Bench (MPTB)

 

Introduction

OTECHOS has developed and constructed two advanced main systems for exposing objects to pressure pulses from a hydraulic liquid (MPTB), as well as for mechanical vibrations (ASVG) with relatively high frequencies. Both tests can be performed simultaneously or only one of them at the time.

The background for our own construction of this equipment was our demand for such tests in order to fulfill the requirements from DNV GL (Det Norske Veritas Germanisher Lloyd), - concerning type approval for OTECHOS’ new metallic seal for piping flanges (Delta V-Seal™).

Generally, most of the approval tests of piping components and pipe connections are similar. However, a thorough seek world-wide turned up with no usable facilities in laboratories or in general industries for relatively heavy test objects.

In accordance to class society requirements, our Multiple Pressure Test Bench exposed our metallic seals for 3 x 10 million cycles in addition 3 x 500.000 multiple level pulses, simulating many years of use in stressful and harsh environment, which our new Delta V-Seal™ endured successfully under DNV GL’s close supervision, making OTECHOS’ Delta V-Seal™ the world’s first DNV GL type approved seal in 2015.

MPTB Hydraulic Pulse Generating System

MPTB Hydraulic Pulse Generating System

The solenoid valves as well as the pressure censor are connected to an I/O equipment (Labview) which communicates with an ordinary computer, running the program for the actual test.

The MPTB can provide a number of pulse sequences with different pressure levels and the durations of each of them. The system, except for the parts in the valves, is free for mechanically moving parts that causes delay in acceleration. Therefore, very sharp flanks almost free for overshoot can be obtained.

The pressure pulses within the sequences ranges from 0 – 100 bar (gauge) with rising and falling flanks within 15 ms when the test objects has low ductility, and some higher on large and more ductile test objects. Higher pressure range requires exchanges of the pressure sensor and some other components in the system.

Using all four accumulators, the sequence also provides 4 pressure levels. Most used for piping components are two levels, hence only two accumulators are in service.

Several tests on components with MPTB has been carried out within the specifications provided by, supervised by and finally approved by DNV GL.

As mentioned above, the MPTB can be running tests simultaneous with our Adjustable Stroke Vibration Generator system (ASVG).

The Multiple Pressure Test Bench (MPTB) and the Testotech laboratory are from 2015 available for clients, such as technology producers, engineering companies, classification societies, universities and research institutes.