The pressure relief valve is damaged

Was there a problem during the selection process of the pressure relief valve? After the steam pressure is reduced, does its temperature also decrease?

The temperature I need is 130°C, and no measures have been taken to reduce the temperature on site; the pressure relief valve breaks after being used for a while.

Are there any requirements regarding traffic volume? Did the pipe diameter change before and after pressure reduction? On my end, the pressure is reduced from 5 MPa to 1 MPa; since the flow rate is very low, around 2 m3/h, the diameter at the pressure regulator changes from 80 to 40, which makes the pressure regulator quite stable.

The Y43H steam pressure regulator is not very effective; it is recommended to replace it with a high-performance regulator, the HYQ-16C

If you reduce the pressure from 12 kilograms to 4 kilograms, the gauge pressure will be 4 kilograms, while the absolute pressure will be 5 kilograms. The temperature corresponding to saturated steam at this pressure is 152 degrees Celsius, and the density is 2.679 kg/m3. If you need a temperature of 130°C, the pressure should be reduced to 2 bar; the temperature corresponding to this pressure is 134°C.

This post was last edited by Watt Energy Saving on 2019-6-19 at 11:09. When the steam flow is high, the pressure can still be controlled; once the steam flow decreases, not only does the pressure fluctuate greatly, but in some cases it even stops working entirely. Through on-site investigations conducted by Watt’s steam engineers, it was found that due to the significant fluctuations in actual steam load, the self-acting pressure control valve kept opening and closing frequently. On one hand, the delay in its response meant that the steam pressure did not meet the required levels for proper control, which in turn affected the quality of the painting applied to the products. On the other hand, the frequent opening and closing of the pressure relief valve lead to excessive wear and erosion of the valve element; moreover, the safety valve located after the pressure relief valve trips frequently, which not only wastes energy and affects production but also causes customers to consider such tripping of the safety valve as a problem. The pressure relief valve should be installed properly, in accordance with the requirements specified in the manual for the Watt PRV2000 pilot-diaphragm type pressure relief and stabilization valve. The typical installation method should refer to the standard setup for pressure reduction stations. The steam pipes before and after the pressure relief valve should be made of clean seamless steel tubes, and all welded areas should have any slag or other debris removed effectively. To prevent flow obstruction and ensure smooth flow before and after the pressure reducing valve, the pipe diameter downstream of the pressure reducing valve should be increased. For diameter changes, eccentric tees should be used to avoid the potential for water hammer and erosion caused by water accumulation. A GL200 steam-specific filter must be installed upstream of the pressure relief valve, with a 100-mesh double-layer stainless steel filter element. A Watt DT580 inverted drum steam trap must be installed upstream of the pressure relief valve, and a drain pipe should be provided in front of the trap ； If the steam transmission distance is long, it is recommended to install a steam-water separator. If there is a lift pipe downstream of the pressure relief valve, a Watt DT580 inverted drum steam trap should also be installed. The diameter of a steam pressure reducing valve cannot be simply equated to that of the steam pipeline; it must be carefully selected based on the steam flow rate, pressure, and pressure difference. If the pressure ratio exceeds 10:1, a series of pressure reduction stations should be used to reduce the pressure in stages. The operating opening degree of the pressure reducing valve should be between 20% and 80%. If the load flow fluctuates by more than 10:1, a parallel pressure reducing station should be used to achieve step-controlled pressure reduction.

130°C is my minimum temperature requirement, but to shorten production time, it is set at around 4 bar. But at the moment, the pressure relief valve breaks down after not lasting long.

The only suggestion is to replace it with a better pressure relief valve

I would like to ask how to calculate pipe diameter changes? Thank you!