Can the setting pressure of the safety valve be reduced?
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I would like to ask an expert: The equipment is equipped with a safety valve of type A42Y-40P, with a nominal diameter of 50, a nominal pressure of 4.0 MPa, a pressure rating of 2.0–2.5 MPa, and a set pressure of 2.3 MPa; the medium handled is steam. With the current process adjustment and the reduced operating pressure of the equipment, is it possible to set the setting pressure of the safety valve at 1 MPa?
It can’t be adjusted, right? Could we use a different type of valve? For details, you can consult the valve manufacturer
It can be reduced; you can do this when checking the valve. But it cannot be increased.
This post was last edited by City Boy on 2017-4-5 16:07: Safety valves made of stainless steel for steam media? That’s way too extravagant. Replace the spring or the safety valve. Since ordinary people can’t replace the spring on their own, it’s better to buy a new one – it’s simpler that way
It’s possible to return it to the manufacturer and ask them to produce springs of a different grade; they might offer some financial subsidy, allowing one to buy another unit. The price is just too high.
Thank you. If we don’t replace the spring and only reduce the pressure, why can’t the safety valve be used?
This post was last edited by City Boy on 2017-4-5 at 20:16. Spring-type safety valves have a set range; they work within that range, but not when the pressure exceeds it. Your safety valve, with a pressure rating of 2.0–2.5 MPa, can only operate within that range of 2.0–2.5 MPa; it won’t work if the pressure is below or above this range. Setting it at 1 Mpa definitely won’t work – the spring is too thick
The set pressure of the safety valve depends on the operating pressure of the pipeline; PA = 1.1P = 2.75. An overpressure of 10% means 2.75*0.1 = 0.275. Thus, the discharge pressure PD = 2.75 + 0.275 = 3.025. Since the operating pressure of all equipment has decreased, it is necessary to recalculate the set pressure of the safety valve – the original range for this value can no longer be maintained. It is recommended to choose flushing. If it needs to be sent back to the factory, it should cost a few thousand yuan to fix it; a new safety valve, on the other hand, costs around over ten thousand yuan.
I’m not sure if your equipment has been replaced. If it hasn’t been replaced, I think there’s no need to adjust the safety valve – the design pressure of your equipment should be higher than the setting pressure of the safety valve. The purpose of a safety valve is to protect the equipment; since the equipment hasn’t been changed, there’s no need to change the safety valve either. However, in that case the safety valve won’t be very effective, as it will only activate when the pressure exceeds 2.3 MPa. If the equipment has been replaced, then a new safety valve is necessary... I’m not sure if what I’m saying is correct