Benoni-based industrial solutions company RHVI Group is marketing the safety-valve testing service AccuTEST for operating pressures of up to 140 bar to the South African mining industry, says RVHI sales manager Derek Coburn.
Leading to this development is RHVI Group’s successful two-year implementation of the AccuTEST solution at power plants in Mauritius.
The company is currently in consultation with a magnesium mine in South Africa to use the solution to verify its safety valves and expects other mines to follow suit once this deal has been finalised.
RHVI Group uses inspection, verification, testing and certification company US-headquartered AccuTEST’s safety-valve testing system (of the same name) to verify the operability of safety valves while they are on line, under full load and/or live.
The ability to test valves while they remain in operation is critical to mining clients, as they do not have to shut down or decrease the operating capacity of their plants.
Other methods of testing safety valves require the infrastructure linked to a safety valve to be shut down to facilitate either a hydraulic liquid or compressed air to be flushed through the system at high pressure to operate the safety valve according to its specified relief parameters or activating pressures. This results in downtime and more time needed to test each valve, whereas the AccuTEST solution can be installed at and used to test each valve, with no limitations being placed on the plant’s output.
Further, the solution can be operated by a two-person team – an operator and an assistant – reducing the time needed to test a single valve to about one-third of the time required when using other methods of safety-valve testing. Valve operation is facilitated by a digital platform using an electronic load cell and laptop.
RHVI Group has been using the AccuTEST solution to test all the safety valves thrice yearly at five Mauritius-based power stations as part of a three-year contract. The company is currently in its third year of the contract.
Coburn says the power utility enquired in 2014 as to whether the company had a system to test safety valves, with a key criteria being that the valves needed to be tested while the power station was operating under full load.
He adds that the AccuTEST solution has proven to be so successful that no client to date has turned down the testing of their safety valves using the system, owing to its efficiency, accuracy and low impact on productivity.
It is nonintrusive to the related valve infrastructure, as the battery-powered valve-testing mechanism only actuates the valve to the required level, which is low enough to ensure it meets its stipulated activating pressure.
Coburn notes that alternative safety-valve testing systems open the safety valves fully and this leads to significant noise being generated, as pressure escapes through the valve and may cause the valves to become contaminated by dust and dirt. “Dust entering a valve can unseat the valve and cause it to wear and leak, thereby compromising its integrity and leading to plant inefficiencies.”
The AccuTEST system registers an audible note once a safety valve has been activated and releases the valve immediately, thereby reducing noise and wear on the valve. It is also accurate to less than 0.5%, which is far more precise than hydraulic or compressed-air valve testing methods, Coburn highlights, adding that in many cases this is even more accurate than when safety valves are tested by their respective manufacturers.
The solution uses two sensors to register the actual lifting of the valve and acoustic recognition once the pressure is released from the system.
Further, human error is mitigated during every step of testing because AccuTEST operates on a digital system – this allows for updates to be uploaded when special or unusual valves are tested.
“If the valve does not open within its specified threshold, we adjust it and test the valve again to verify the new settings in line with the specified operating parameters,” explains Coburn, adding that once valves have passed the test, reporting logs are compiled and issued to the client. These logs detail the performance of each valve and any adjustments made by the RHVI Group technician after testing.
The system also enhances the safety of the testing technician, as valves can be tested from a distance, thereby mitigating any risk of injury such as burns from escaping steam.
RHVI Group has undertaken certification of the AccuTEST system through local conformity regulator the South African National Accreditation System to ensure the accuracy and traceability of results.
The system is also certified by the American Society of Mechanical Engineers.