Аngle grinder

How A Control Valve Can Avoid an Angle Grinder Attack

There is scale or spit residue in each pipeline after welding. Washing and blowing with steam at a rate of up to 90 m/sec. has the scale impact on the control valve as an angle grinder attack.

Two integrated steam converting valves, 1612-09 250/400, manufactured by HORA installed on the pipeline of a boiler of an 800 MW power generating unit under construction.

Сonverting клапаны

Two integrated steam converting valves

After a hydrostatic pressure test performed with the pipeline, two steam-converting valves look perfect on the outside, but the situation inside is different.

Scale or spit is an inevitable result of welding and scalping in the pipeline, and as soon as water comes inside, the control valve turns into a so-called strainer, entrapping the largest spit particles.

Spit inside the pipeline valve

Spit inside the pipeline valve

Fortunately, this valve suffered no major damage and is still in a condition to function reliably. The water rate in the pipeline is around 3 m/sec. and the valve material easily withstood the water fill-up under pressure, even with foreign particles present.

Yet, it is necessary to disassemble and to clean the valve. Otherwise, washing and blowing the pipeline with steam at a rate of up to 90 m/sec. will result in the scale impact on the valve construction comparable to an angle grinder attack, whose linear rate of the rotary disc may reach 80 m/sec.

Thus, VAPOR service experts took a control unit out of the valve and closed the valve body with a blind cover. The valve, empty inside, will easily suffer get through and blowing. After that, its operating part will be reassembled inside the valve body to control clean the steam flow. The plant warranty certificate will be valid even after the performance of this work.

Integrated valve trim

Integrated valve trim

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