【Daily Question 20090406-07】Regarding instrument air pressure
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There are several pressures of gauge air that you have seen. This post was last edited by wwxxss_1 on 2009-4-7 09:55]
The instrument air pressure required for the simplest self-regulating valves is 0.14 MPa, while that for regulating valves with diaphragm seals is 0.28 MPa. The on-off disc valve we are using now: instrument air pressure of 0.5~0.6 MPa.
Pressure of instrument air: There are generally two common types of control valves, with pressures of 0–0.14 MPaG and 0–0.28 MPaG. The latter option allows for a smaller size of the actuator, which facilitates installation. Pneumatic on-off valves generally require a pressure range of 0.45–0.7 MPaG.
The common pressures for instrument air supply are 0.14 and 0.28 MPa; other shut-off valves require a pressure of around 0.6 MPa, while backwashing requires a pressure of around 0.8 MPa.
The instrument air pressure required for the simplest self-regulating valves is 0.14 MPa, while that for regulating valves with diaphragm seals is 0.28 MPa. The on-off disc valve we are using now: instrument air pressure of 0.5~0.6 MPa.
Supply pressure: 0.7MPa； 0.6MPa ； 0.4MPa ； Operating pressure of 0.28 MPa control valve: 0.02~0.14 MPa ； 0.08~0.28MPa ； 0.35~0.7MPa
Pneumatic on-off valves generally require a pressure range of 0.45–0.7 MPaG, and have high requirements regarding moisture content
The air supply pressures for the control valves we have used are as follows: 1. The operating pressure of the diaphragm valve in Wuzhong is 0.02~0.14 MPa； 2. The operating pressure of Yamaki’s control valves is 0.02~0.14 MPa ； 0.08~0.28MPa ； 3. The operating pressure of the butterfly valve in KOSO Wuxi tooling is 0.35~0.7 MPa ； 4. The pneumatic ball valve of Gemi operates at a pressure range of 0.35~0.7 MPa ； 5. The operating pressure of the precision-controlled pneumatic ball valve is 0.35~0.7 MPa.
Section 4.2 on gas source pressure in the \"SH3020-2001 Standards for the Design of Gas Supply Systems for Petrochemical Instruments\" stipulates that after passing through filters and pressure regulators, the nominal pressure of the gas supply at the instrument input side can be 140 kPa, 160 kPa, 200 kPa, 260 kPa, 280 kPa, 350 kPa, 400 kPa, 550 kPa, or 700 kPa. The allowable pressure fluctuation range is ±10% of its nominal pressure.
The pressures of the used instrument air were 0.14, 0.28, 0.35, 0.45–0.7
We used 0.15 before, but now all the designs use 0.5
0.28 MPa is commonly used for control valves and shut-off valves.
The lower limit for the signal pressure of pneumatic instruments is specified as 0.02 MPa
The control valve range is 0.2MPa to 0.6MPa.
1. According to the requirements of pneumatic instruments, the output pressure range of the air supply unit is divided into the following two categories: 500–700 kPa (G) and 300–500 kPa (G). 2. The upper limit of the output pressure of the air supply unit should be the highest pressure it can deliver under normal operating conditions. When it meets the actual requirements of engineering design, additional pressurization measures can be taken. 3. The lower limit value of the output pressure of the air supply unit is the lowest pressure it can deliver; if the pressure falls below this value, an audio-visual alarm should be triggered. 4. After passing through the filter and pressure regulator, the nominal pressure of the air supply at the instrument input side is 1,400 kPa, 1,600 kPa, 2,000 kPa, 2,600 kPa, 2,800 kPa, 3,500 kPa, 4,000 kPa, 550 kPa, and 7,000 kPa. The allowable pressure fluctuation range is ±10% of its nominal pressure.
There are only two types of pressure gauges we use: those with an operating pressure range of 0.02~0.14 MPa and 0.08~0.28 MPa
The ones I’ve seen are 0.15 and 0.25 or 0.3 MPA
PSA switch valves for hydrogen production at 0.4~0.8 MPa; everything else has already been mentioned
I think they’re more or less the same; generally it’s 1.4 and 2.8 kilograms, with the total gas supply being around 6 kilograms
The exact value depends on the type of valve; for regular control valves, the spring range is usually around 0.14 MPa, while those with a larger spring range have a range of 0.24–0.28 MPa. For shut-off valves, the air pressure is generally between 0.5–0.7 MPa, with the overall supply pressure being 0.8 MPa!
Instrument air storage tank: Operating pressure: 0.8 MPag. Air buffer tank: Operating pressure: 0.9 MPag