Is the range of the pressure gauge on the equipment taken into account with regard to the set pressure of the safety valve?
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For example, if the operating pressure of the equipment is 0.24 MpaG and the set pressure of the safety valve on the equipment is 0.68 MpaG, does that mean the range of my pressure gauge needs to cover 0.68 MpaG?
The appropriate selection range for a pressure gauge generally requires that the normal operating pressure fall between 1/3 and 2/3 of the gauge’s range. Three times 0.24 MPa is 0.72 MPa, which is higher than the set pressure of the safety valve, which is 0.68 MPa. In the range shown on the pressure gauge, the value above that is 1.0 MPa, which is too high; the value below is 0.6 MPa, which is more appropriate. Therefore, I think 0.6 MPa is sufficient, but considering the pressure setting of the safety valve, 1.0 MPa is also acceptable. But when there are more than one pressure gauge in the system, it’s better to use different range specifications at various locations.
It is better to use pressure gauges with different ranges depending on the location and pressure.
Of course it needs to be taken into consideration; not only the set pressure of the safety valve, but also the discharge pressure. At least, when the safety valve discharges, it shouldn’t exceed its rated range.
That’s how I think about it. I haven’t paid attention to this aspect in detail yet; I’ll look at it on-site when I get the chance. From what I understand, when a device is equipped both with a safety valve and a pressure gauge, if the range of the pressure gauge isn’t sufficient to cover the pressure at which the safety valve opens, could the gauge get damaged as a result? If it can be damaged, then it’s necessary to consider the pressure range appropriate for that safety valve. If the gauge isn’t affected by going beyond its range, then there’s no need to worry about it. I haven’t dealt with this situation personally; those who have experience can go and check the conditions on-site.
I don’t understand why the set pressure of your safety valves is so much higher than the operating pressure If this pressure gauge is located near the safety valve, it’s better to use one with a pressure range of 1 MPa; otherwise, the gauge may get damaged
Indeed, the design pressure is generally set at 1.1 times the maximum operating pressure, while the relief pressure is at most 1.21 times the design pressure. According to the range specified in ylb913, by setting the pressure at 0.7 and the relief pressure at 0.9, the entire range can be covered.
No need to consider it. Pressure gauges come in series; ask those who specialize in instruments
For this example, I will choose a range of 0.6 MpaG. The over-range capability of a pressure gauge is generally 1.3, meaning it can still return to normal readings even after reaching 0.78, without any impact on accuracy. Such examples are common in vacuum systems; for instance, the operating pressure is at -80 KPA under negative pressure, but the nitrogen pressure is maintained at 100 KPA gauge pressure, with the safety valve set at 150 KPa gauge pressure. When setting up a pressure gauge, it’s important to clarify the requirements: use a negative pressure gauge for operations that involve negative pressure, and a positive pressure gauge for those that involve N2 pressure maintenance. If a gauge with a composite range of -100---+150 KPA is used, readings cannot be taken accurately at either end.
There are regulatory requirements for liquefied hydrocarbon spheres as well